EANM procedural guidelines for radionuclide myocardial perfusion imaging with SPECT and SPECT/CT: 2015 revision.

PubMed

Verberne, Hein J; Acampa, Wanda; Anagnostopoulos, Constantinos; Ballinger, Jim; Bengel, Frank; De Bondt, Pieter; Buechel, Ronny R; Cuocolo, Alberto; van Eck-Smit, Berthe L F; Flotats, Albert; Hacker, Marcus; Hindorf, Cecilia; Kaufmann, Philip A; Lindner, Oliver; Ljungberg, Michael; Lonsdale, Markus; Manrique, Alain; Minarik, David; Scholte, Arthur J H A; Slart, Riemer H J A; Trägårdh, Elin; de Wit, Tim C; Hesse, Birger

2015-11-01

Since the publication of the European Association of Nuclear Medicine (EANM) procedural guidelines for radionuclide myocardial perfusion imaging (MPI) in 2005, many small and some larger steps of progress have been made, improving MPI procedures. In this paper, the major changes from the updated 2015 procedural guidelines are highlighted, focusing on the important changes related to new instrumentation with improved image information and the possibility to reduce radiation exposure, which is further discussed in relation to the recent developments of new International Commission on Radiological Protection (ICRP) models. Introduction of the selective coronary vasodilator regadenoson and the use of coronary CT-contrast agents for hybrid imaging with SPECT/CT angiography are other important areas for nuclear cardiology that were not included in the previous guidelines. A large number of minor changes have been described in more detail in the fully revised version available at the EANM home page: http://eanm.org/publications/guidelines/2015_07_EANM_FINAL_myocardial_perfusion_guideline.pdf .

Incorporation of paramagnetic, fluorescent and PET/SPECT contrast agents into liposomes for multimodal imaging

PubMed Central

Mitchell, Nick; Kalber, Tammy L.; Cooper, Margaret S.; Sunassee, Kavitha; Chalker, Samantha L.; Shaw, Karen P.; Ordidge, Katherine L.; Badar, Adam; Janes, Samuel M.; Blower, Philip J.; Lythgoe, Mark F.; Hailes, Helen C.; Tabor, Alethea B.

2013-01-01

A series of metal-chelating lipid conjugates has been designed and synthesized. Each member of the series bears a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) macrocycle attached to the lipid head group, using short n-ethylene glycol (n-EG) spacers of varying length. Liposomes incorporating these lipids, chelated to Gd3+, 64Cu2+, or 111In3+, and also incorporating fluorescent lipids, have been prepared, and their application in optical, magnetic resonance (MR) and single-photon emission tomography (SPECT) imaging of cellular uptake and distribution investigated in vitro and in vivo. We have shown that these multimodal liposomes can be used as functional MR contrast agents as well as radionuclide tracers for SPECT, and that they can be optimized for each application. When shielded liposomes were formulated incorporating 50% of a lipid with a short n-EG spacer, to give nanoparticles with a shallow but even coverage of n-EG, they showed good cellular internalization in a range of tumour cells, compared to the limited cellular uptake of conventional shielded liposomes formulated with 7% 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(polyethyleneglycol)2000] (DSPE-PEG2000). Moreover, by matching the depth of n-EG coverage to the length of the n-EG spacers of the DOTA lipids, we have shown that similar distributions and blood half lives to DSPE-PEG2000-stabilized liposomes can be achieved. The ability to tune the imaging properties and distribution of these liposomes allows for the future development of a flexible tri-modal imaging agent. PMID:23131536

Multimodality imaging using SPECT/CT and MRI and ligand functionalized 99mTc-labeled magnetic microbubbles

PubMed Central

2013-01-01

Background In the present study, we used multimodal imaging to investigate biodistribution in rats after intravenous administration of a new 99mTc-labeled delivery system consisting of polymer-shelled microbubbles (MBs) functionalized with diethylenetriaminepentaacetic acid (DTPA), thiolated poly(methacrylic acid) (PMAA), chitosan, 1,4,7-triacyclononane-1,4,7-triacetic acid (NOTA), NOTA-super paramagnetic iron oxide nanoparticles (SPION), or DTPA-SPION. Methods Examinations utilizing planar dynamic scintigraphy and hybrid imaging were performed using a commercially available single-photon emission computed tomography (SPECT)/computed tomography (CT) system. For SPION containing MBs, the biodistribution pattern of 99mTc-labeled NOTA-SPION and DTPA-SPION MBs was investigated and co-registered using fusion SPECT/CT and magnetic resonance imaging (MRI). Moreover, to evaluate the biodistribution, organs were removed and radioactivity was measured and calculated as percentage of injected dose. Results SPECT/CT and MRI showed that the distribution of 99mTc-labeled ligand-functionalized MBs varied with the type of ligand as well as with the presence of SPION. The highest uptake was observed in the lungs 1 h post injection of 99mTc-labeled DTPA and chitosan MBs, while a similar distribution to the lungs and the liver was seen after the administration of PMAA MBs. The highest counts of 99mTc-labeled NOTA-SPION and DTPA-SPION MBs were observed in the lungs, liver, and kidneys 1 h post injection. The highest counts were observed in the liver, spleen, and kidneys as confirmed by MRI 24 h post injection. Furthermore, the results obtained from organ measurements were in good agreement with those obtained from SPECT/CT. Conclusions In conclusion, microbubbles functionalized by different ligands can be labeled with radiotracers and utilized for SPECT/CT imaging, while the incorporation of SPION in MB shells enables imaging using MR. Our investigation revealed that biodistribution may be modified using different ligands. Furthermore, using a single contrast agent with fusion SPECT/CT/MR multimodal imaging enables visualization of functional and anatomical information in one image, thus improving the diagnostic benefit for patients. PMID:23442550

Novel, dually radiolabeled peptides for simultaneous monitoring of enzymatic activity and protein targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Efrem Mebrahtu, Suzanne Lapi

2012-12-13

This application investigated a novel imaging approach to develop methods to incorporate multiple radionuclides into a single peptide at chemoselective sites for simultaneous monitoring of cell-bound protein targets as well as specific enzymatic activity, both of which are associated with enhanced tumor growth and metastasis. This imaging construct was synthesized in such a manner so that the PET radionuclide will remain associated with the tumor cells and the SPECT radionuclide was cleaved from the imaging agent. Measurement of the PET agent only will yield information about the tumor marker density while measurement of the amount of co-localization and mismatch ofmore » the two radionuclides will yield information about the enzymatic activity. This coincident measuring technique using both PET and SPECT agents allows us to draw correlations involving the interactions of enzymes (cathepsin, serine-protease urokinase (uPA) and matrix metalloproteases) and other cellular proteins which play a role in cancer growth and metastasis. This technique will allow for studies in xenograft or genetic models of cancer in the same animal at the same time, thus eliminating problems that may occur when trying to invoke comparisons across animals or timepoints. By using radionuclide imaging as opposed to other imaging modalities, this technique has the potential to be translatable and can exploit the high specific activity probes which can be generated with radiotracers. The proof of principle test of this system investigated simultaneous monitoring of matrix metalloprotease (MMP) activity in the extracellular matrix (ECM) as well as density of integrins on the cell surface, both of which can serve as tumor markers. The outcomes/deliverables of this project were as follows: 1. Peptides were synthesized dually labeled at chemospecific sites with PET and SPECT agents. 2. Stability (intrinsic and to radiolysis) and specific activity of these labeled compounds were determined. 3. The feasibility of using these agents for simultaneous monitoring of MMP-2 enzymatic activity and ²3 integrin density was demonstrated in several in vitro assays Radiotracers can be detected at concentrations up to 1000 fold lower than those labeled with non-radioactive markers (e.g. MRI contrast agents), thus using this technique has the advantage of very high sensitivity to measure these processes in vivo. Hence, the development of an efficient approach to the dual labeling of these molecular probes is embodied within this project, with the end result yielding a molecular imaging probe with the highest specific activity possible. An advantage to this dual labeling approach is the ability to measure two different biochemical processes at the same time, a benefit which is not possible in scans involving protocols utilizing two different radiolabeled agents injected sequentially. Another advantage to this technique is the ability to measure enzymatic activity in the form of substrate cleavage. This can only be achieved with a dually labeled compound as has been demonstrated in the case of FRET1. To our knowledge this is the first instance of a measurement of enzymatic substrate cleavage by a dually labeled PET/SPECT radionuclide imaging agent.« less

Multimodal molecular imaging reveals high target uptake and specificity of 111In and 68Ga labeled fibrin-binding probes for thrombus detection in rats

PubMed Central

Oliveira, Bruno L.; Blasi, Francesco; Rietz, Tyson A.; Rotile, Nicholas J.; Day, Helen; Caravan, Peter

2016-01-01

We recently showed the high target specificity and favorable imaging properties of 64Cu and Al18F positron emission tomography (PET) probes for non-invasive imaging of thrombosis. Here, our aim was to evaluate new derivatives labeled with either with 68Ga, 111In, or 99mTc as thrombus imaging agents for PET and single-photon emission computed tomography (SPECT). In this study, the feasibility and potential of these probes for thrombus imaging was assessed in detail in two animal models of arterial thrombosis. The specificity of the probes was further evaluated using a triple-isotope approach with multimodal SPECT/PET/CT imaging. Methods Radiotracers were synthesized using a known fibrin-binding peptide conjugated to NODAGA, DOTA-MA, or a diethylenetriamine ligand (DETA-PA), followed by labeling with 68Ga (FBP14, 68Ga-NODAGA), 111In (FBP15, 111In-DOTA-MA) or 99mTc (FBP16, 99mTc(CO)3-DETA-PA), respectively. PET or SPECT imaging, biodistribution, pharmacokinetics and metabolic stability were evaluated in rat models of mural and occlusive carotid artery thrombosis. In vivo target specificity was evaluated by comparing the distribution of the SPECT and PET probes with preformed 125I-labeled thrombi and with a non-binding control probe using SPECT/PET/CT imaging. Results All three radiotracers showed similar affinity to soluble fibrin fragment DD(E) (Ki = 0.53–0.83 μM). After the kidneys, the highest uptake of 68Ga-FBP14 and 111In-FBP15 was in the thrombus (1.0 ± 0.2% ID/g) with low off-target accumulation. Both radiotracers underwent fast systemic elimination (t1/2 = 8-15 min) through the kidneys, which led to highly conspicuous thrombi on PET and SPECT images. 99mTc-FBP16 displayed low target uptake and distribution consistent with aggregation and/or degradation. Triple isotope imaging experiments showed that both 68Ga-FBP14 and 111In-FBP15, but not the nonbinding derivative 64Cu-D-Cys-FBP8, detected the location of the 125I-labeled thrombus, confirming high target specificity. Conclusion 68Ga-FBP14 and 111In-FBP15 have high fibrin affinity and thrombus specificity, and represent useful PET and SPECT probes for thrombus detection. PMID:26251420

The ubiquitous DOTA and its derivatives: the impact of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid on biomedical imaging.

PubMed

Stasiuk, Graeme J; Long, Nicholas J

2013-04-07

Over the last twenty-five years 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) has made a significant impact on the field of diagnostic imaging. DOTA is not the only metal chelate in use in medical diagnostics, but it is the only one to significantly impact on all of the major imaging modalities Magnetic Resonance (MR), Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), and Fluorescence imaging. This crossover of modalities has been possible due to the versatility of DOTA firstly, to complex a variety of metal ions and secondly, the ease with which it can be modified for different disease states. This has driven research over the last two decades into the chemistry of DOTA and the modification of the substituent pendant arms of this macrocycle to create functional, targeted and dual-modal imaging agents. The primary use of DOTA has been with the lanthanide series of metals, gadolinium for MRI, europium and terbium for fluorescence and neodymium for near infra-red imaging. There are now many research groups dedicated to the use of lanthanides with DOTA although other chelates such as DTPA and NOTA are being increasingly employed. The ease with which DOTA can be conjugated to peptides has given rise to targeted imaging agents seen in the PET, SPECT and radiotherapy fields. These modalities use a variety of radiometals that complex with DOTA, e.g.(64)Cu and (68)Ga which are used in clinical PET scans, (111)In, and (90)Y for SPECT and radiotherapy. In this article, we will demonstrate the remarkable versatility of DOTA, how it has crossed the imaging modality boundaries and how it has been successfully transferred into the clinic.

Recent Trends in Soft Tissue Infection Imaging

PubMed Central

Petruzzi, Nicholas; Shanthly, Nylla; Thakur, Mathew

2009-01-01

This article discusses the current techniques and future directions of infection imaging with particular attention to respiratory, CNS, abdominal, and postoperative infections. The agents currently in use localize to areas of infection and inflammation. An infection specific imaging agent would greatly improve the utility of scintigraphy in imaging occult infections. The superior spatial resolution of 18F-FDG PET and its lack of reliance on a functional immune system, gives this agent certain advantages over the other radiopharmaceuticals. In respiratory infection imaging, an important advancement would be the ability to quantitatively delineate lung inflammation, allowing one to monitor the therapeutic response in a variety of conditions. Current studies suggest PET should be considered the most accurate quantitative method. Scintigraphy has much to offer in localizing abdominal infection as well as inflammation. We may begin to see a gradual increase in the usage of FDG PET in detecting occult abdominal infections. Commonly used modalities for imaging inflammatory bowel disease are scintigraphy with 111In-oxine/99mTc-HMPAO labeled autologous white blood cells. The literature on CNS infection imaging is relatively scarce. Few clinical studies have been performed and numerous new agents have been developed for this use with varying results. Further studies are needed to more clearly delineate the future direction of this field. In evaluating the post-operative spine, 99mTc-ciprofloxacin SPECT was reported to be >80% sensitive in patients more than 6 months post-surgery. FDG PET has also been suggested for this purpose and may play a larger role than originally thought. It appears PET/CT is gaining support, especially in imaging those with fever of unknown origin or nonfunctional immune systems. While an infection specific agent is lacking, the development of one would greatly advance our ability to detect, localize, and quantify infections. Overall, imaging such an agent via SPECT/CT or PET/CT will pave the way for greater clinical reliability in the localization of infection. PMID:19187804

3D SPECT/CT fusion using image data projection of bone SPECT onto 3D volume-rendered CT images: feasibility and clinical impact in the diagnosis of bone metastasis.

PubMed

Ogata, Yuji; Nakahara, Tadaki; Ode, Kenichi; Matsusaka, Yohji; Katagiri, Mari; Iwabuchi, Yu; Itoh, Kazunari; Ichimura, Akira; Jinzaki, Masahiro

2017-05-01

We developed a method of image data projection of bone SPECT into 3D volume-rendered CT images for 3D SPECT/CT fusion. The aims of our study were to evaluate its feasibility and clinical usefulness. Whole-body bone scintigraphy (WB) and SPECT/CT scans were performed in 318 cancer patients using a dedicated SPECT/CT systems. Volume data of bone SPECT and CT were fused to obtain 2D SPECT/CT images. To generate our 3D SPECT/CT images, colored voxel data of bone SPECT were projected onto the corresponding location of the volume-rendered CT data after a semi-automatic bone extraction. Then, the resultant 3D images were blended with conventional volume-rendered CT images, allowing to grasp the three-dimensional relationship between bone metabolism and anatomy. WB and SPECT (WB + SPECT), 2D SPECT/CT fusion, and 3D SPECT/CT fusion were evaluated by two independent reviewers in the diagnosis of bone metastasis. The inter-observer variability and diagnostic accuracy in these three image sets were investigated using a four-point diagnostic scale. Increased bone metabolism was found in 744 metastatic sites and 1002 benign changes. On a per-lesion basis, inter-observer agreements in the diagnosis of bone metastasis were 0.72 for WB + SPECT, 0.90 for 2D SPECT/CT, and 0.89 for 3D SPECT/CT. Receiver operating characteristic analyses for the diagnostic accuracy of bone metastasis showed that WB + SPECT, 2D SPECT/CT, and 3D SPECT/CT had an area under the curve of 0.800, 0.983, and 0.983 for reader 1, 0.865, 0.992, and 0.993 for reader 2, respectively (WB + SPECT vs. 2D or 3D SPECT/CT, p < 0.001; 2D vs. 3D SPECT/CT, n.s.). The durations of interpretation of WB + SPECT, 2D SPECT/CT, and 3D SPECT/CT images were 241 ± 75, 225 ± 73, and 182 ± 71 s for reader 1 and 207 ± 72, 190 ± 73, and 179 ± 73 s for reader 2, respectively. As a result, it took shorter time to read 3D SPECT/CT images than 2D SPECT/CT (p < 0.0001) or WB + SPECT images (p < 0.0001). 3D SPECT/CT fusion offers comparable diagnostic accuracy to 2D SPECT/CT fusion. The visual effect of 3D SPECT/CT fusion facilitates reduction of reading time compared to 2D SPECT/CT fusion.

Time course evaluation of myocardial perfusion after reperfusion therapy by 99mTc-tetrofosmin SPECT in patients with acute myocardial infarction.

PubMed

Tanaka, R; Nakamura, T

2001-09-01

Myocardial perfusion imaging with 99mTc-labeled agents immediately after reperfusion therapy can underestimate myocardial salvage. It is also conceivable that delayed imaging is useful for assessing the risk area. However, to our knowledge, very few studies have sequentially evaluated these image changes. We conducted 99mTc-tetrofosmin (TF) and 123I-beta-methyl-p-iodophenylpentadecanoic acid (BMIPP) SPECT before and after reperfusion to treat acute myocardial infarction and quantified changes in TF myocardial accumulation and reverse redistribution. Seventeen patients with a first myocardial infarction underwent successful reperfusion. We examined SPECT images obtained at the onset (preimage), those acquired 30 min (early image) and 6 h (delayed image) after TF injection, and images acquired 1, 4, 7, and 20 d after reperfusion (post-1-d, post-4-d, post-7-d, and post-20-d image, respectively). We also examined BMIPP SPECT images after 7 +/- 1.8 d (BMIPP image). Polar maps were divided into 48 segments to calculate percentage uptake, and time course changes in segment numbers below 60% were observed as abnormal area. Moreover, cardiac function was analyzed by gated TF SPECT on 1 and 20 d after reperfusion. In reference to the abnormal area on the early images, the post-1-d image was significantly improved compared with the preimage (P < 0.01) as was the post-7-d image compared with the post-1-d and post-4-d images (P < 0.05, respectively). However, post-20-d and post-7-d images did not significantly differ. Therefore, the improvement in myocardial accumulation reached a plateau 7 d after reperfusion. On the other hand, the abnormal area on the delayed images was significantly greater (P < 0.01) compared with that on the early images from 4 to 20 d after reperfusion, as the value was essentially constant. The correlations of the abnormal area between the preimage and the post-7-d delayed image, the preimage and the BMIPP image, and the post-7-d delayed image and the BMIPP image were very close (r = 0.963, r = 0.981, and r = 0.975, respectively). Gated TF SPECT revealed that the left ventricular ejection fraction was not significantly different (P = not significant) between 1 and 20 d after reperfusion, but regional wall motion was significantly different after reperfusion (P < 0.05). These results suggest that the interval between reperfusion therapy and TF SPECT should be 7 d to evaluate the salvage effect and that TF delayed and BMIPP images are both useful in estimation of risk area.

4-fluoroalkyl-3-halophenyl nortropanes

DOEpatents

Goodman, Mark M.; Chen, Ping

2002-06-04

A series of compounds in the 4-fluoroalkyl-3-halophenyl nortropanes family are described as diagnostic and therapeutic agents for diseases associated with serotonin transporter dysfunction. These compounds bind to serotonin transporter protein with high affinity and selectivity. The invention provides methods of synthesis which incorporate radioisotopic halogens at a last step which permit high radiochemical yield and maximum usable product life. The radiolabeled compounds of the invention are useful as imaging agents for visualizing the location and density of serotonin transporter by PET and SPECT imaging.

18F-positron-emitting/fluorescent labeled erythrocytes allow imaging of internal hemorrhage in a murine intracranial hemorrhage model

PubMed Central

Wang, Ye; An, Fei-Fei; Chan, Mark; Friedman, Beth; Rodriguez, Erik A; Tsien, Roger Y; Aras, Omer

2017-01-01

An agent for visualizing cells by positron emission tomography is described and used to label red blood cells. The labeled red blood cells are injected systemically so that intracranial hemorrhage can be visualized by positron emission tomography (PET). Red blood cells are labeled with 0.3 µg of a positron-emitting, fluorescent multimodal imaging probe, and used to non-invasively image cryolesion induced intracranial hemorrhage in a murine model (BALB/c, 2.36 × 108 cells, 100 µCi, <4 mm hemorrhage). Intracranial hemorrhage is confirmed by histology, fluorescence, bright-field, and PET ex vivo imaging. The low required activity, minimal mass, and high resolution of this technique make this strategy an attractive alternative for imaging intracranial hemorrhage. PET is one solution to a spectrum of issues that complicate single photon emission computed tomography (SPECT). For this reason, this application serves as a PET alternative to [99mTc]-agents, and SPECT technology that is used in 2 million annual medical procedures. PET contrast is also superior to gadolinium and iodide contrast angiography for its lack of clinical contraindications. PMID:28054494

High Resolution Pre-Clinical CT and SPECT Imaging Techniques for Investigating Flow and Transport Mechanisms in Porous Media

NASA Astrophysics Data System (ADS)

Dogan, M.; Moysey, S. M.; Mamun, A. A.; DeVol, T. A.; Powell, B. A.; Murdoch, L. C.

2017-12-01

Single Photon Emission Computed Tomography (SPECT) and x-ray Computed Tomography (CT) are both high-resolution imaging methods for investigating laboratory scale samples. We have recently conducted several experiments to determine the capabilities of two preclinical imaging systems; the imaging resolution of the two systems studied were found to be 0.2 mm for CT and 2-4 mm for SPECT depending on the tracer and scan times. While the resolution of these instruments is not sufficient for imaging the pore structure of most soils, it is sufficient to resolve macropore structures such as cracks and root channels and to observe their impact on transport. For example, we have used CT scans to monitor the formation of desiccation cracks within soils obtained from the Savannah River Site. We were then able to observe the interaction between the crack network and pore matrix during an infiltration experiment by spiking the infiltrating water with an iodide contrast agent as a tracer. We found a complex interaction between the flow systems, where flow shifted from matrix dominated at low flow rates to macropore dominated at high flow rates. SPECT imaging is capable of monitoring the distribution of gamma-ray emitting radionuclides in 3D. It is therefore also a useful tool for monitoring transport processes, but is particularly powerful when a redox sensitive isotope like 99mTc is used as the tracer. We show an example of a transport experiment where a 99mTc solution is passed through a column containing zones with different redox properties, i.e., a zone amended with titanomagnetite, another with anatase, and a third with silica flour. The 99mTc is captured by the strongly reducing materials, but not the zone with silica flour. The example illustrates how these imaging modalities can be used to discriminate between chemical and physical processes controlling fate and transport of the radionuclide. In particular, CT and SPECT can be used to image contaminant transport in lab scale columns by combining the structural information obtained from CT with the concentration distributions from SPECT.

Dual-radiolabeled nanoparticle probes for depth-independent in vivo imaging of enzyme activation

NASA Astrophysics Data System (ADS)

Black, Kvar C. L.; Zhou, Mingzhou; Sarder, Pinaki; Kuchuk, Maryna; Al-Yasiri, Amal Y.; Gunsten, Sean P.; Liang, Kexian; Hennkens, Heather M.; Akers, Walter J.; Laforest, Richard; Brody, Steven L.; Cutler, Cathy S.; Achilefu, Samuel

2018-02-01

Quantitative and noninvasive measurement of protease activities has remained an imaging challenge in deep tissues such as the lungs. Here, we designed a dual-radiolabeled probe for reporting the activities of proteases such as matrix metalloproteinases (MMPs) with multispectral single photon emission computed tomography (SPECT) imaging. A gold nanoparticle (NP) was radiolabeled with 125I and 111In and functionalized with an MMP9-cleavable peptide to form a multispectral SPECT imaging contrast agent. In another design, incorporation of 199Au radionuclide into the metal crystal structure of gold NPs provided a superior and stable reference signal in lungs, and 111In was linked to the NP surface via a protease-cleavable substrate, which can serve as an enzyme activity reporter. This work reveals strategies to correlate protease activities with diverse pathologies in a tissue-depth independent manner.

Tunable and noncytotoxic PET/SPECT-MRI multimodality imaging probes using colloidally stable ligand-free superparamagnetic iron oxide nanoparticles

PubMed Central

Pham, TH Nguyen; Lengkeek, Nigel A; Greguric, Ivan; Kim, Byung J; Pellegrini, Paul A; Bickley, Stephanie A; Tanudji, Marcel R; Jones, Stephen K; Hawkett, Brian S; Pham, Binh TT

2017-01-01

Physiologically stable multimodality imaging probes for positron emission tomography/single-photon emission computed tomography (PET/SPECT)-magnetic resonance imaging (MRI) were synthesized using the superparamagnetic maghemite iron oxide (γ-Fe2O3) nanoparticles (SPIONs). The SPIONs were sterically stabilized with a finely tuned mixture of diblock copolymers with either methoxypolyethylene glycol (MPEG) or primary amine NH2 end groups. The radioisotope for PET or SPECT imaging was incorporated with the SPIONs at high temperature. 57Co2+ ions with a long half-life of 270.9 days were used as a model for the radiotracer to study the kinetics of radiolabeling, characterization, and the stability of the radiolabeled SPIONs. Radioactive 67Ga3+ and Cu2+-labeled SPIONs were also produced successfully using the optimized conditions from the 57Co2+-labeling process. No free radioisotopes were detected in the aqueous phase for the radiolabeled SPIONs 1 week after dispersion in phosphate-buffered saline (PBS). All labeled SPIONs were not only well dispersed and stable under physiological conditions but also noncytotoxic in vitro. The ability to design and produce physiologically stable radiolabeled magnetic nanoparticles with a finely controlled number of functionalizable end groups on the SPIONs enables the generation of a desirable and biologically compatible multimodality PET/SPECT-MRI agent on a single T2 contrast MRI probe. PMID:28184160

Multimodality Molecular Imaging of [18F]-Fluorinated Carboplatin Derivative Encapsulated in [111In]-Labeled Liposomes

NASA Astrophysics Data System (ADS)

Lamichhane, Narottam

Platinum based chemotherapy is amongst the mainstream DNA-damaging agents used in clinical cancer therapy today. Agents such as cisplatin, carboplatin are clinically prescribed for the treatment of solid tumors either as single agents, in combination, or as part of multi-modality treatment strategy. Despite the potent anti-tumor activity of these drugs, overall effectiveness is still hampered by inadequate delivery and retention of drug in tumor and unwanted normal tissue toxicity, induced by non-selective accumulation of drug in normal cells and tissues. Utilizing molecular imaging and nanoparticle technologies, this thesis aims to contribute to better understanding of how to improve the profile of platinum based therapy. By developing a novel fluorinated derivative of carboplatin, incorporating a Flourine-18 (18F) moiety as an inherent part of the molecule, quantitative measures of drug concentration in tumors and normal tissues can be directly determined in vivo and within the intact individual environment. A potential impact of this knowledge will be helpful in predicting the overall response of individual patients to the treatment. Specifically, the aim of this project, therefore, is the development of a fluorinated carboplatin drug derivative with an inherent positron emission tomography (PET) imaging capability, so that the accumulation of the drug in the tumor and normal organs can be studied during the course of therapy . A secondary objective of this research is to develop a proof of concept for simultaneous imaging of a PET radiolabeled drug with a SPECT radiolabeled liposomal formulation, enabling thereby bi-modal imaging of drug and delivery vehicle in vivo. The approach is challenging because it involves development in PET radiochemistry, PET and SPECT imaging, drug liposomal encapsulation, and a dual-modal imaging of radiolabeled drug and radiolabeled vehicle. The principal development is the synthesis of fluorinated carboplatin 19F-FCP using 2-(5-fluoro-pentyl)-2-methyl malonic acid as the labeling agent to coordinate with the cisplatin aqua complex. It was then used to treat various cell lines and compared with cisplatin and carboplatin at different concentrations ranging from 0.001 microM to 100 microM for 72 hrs and 96 hrs. IC50 values calculated from cell viability indicated that 19F-FCP is a more potent drug than Carboplatin. Manual radiosynthesis and characterization of [18F]-FCP was performed using [18F]-2-(5-fluoro-pentyl)-2-methyl malonic acid with coordination with cisplatin aqua complex. Automated radiosynthesis of [18F]-FCP was optimized using the manual synthetic procedures and using them as macros for the radiosynthesizer. [18F]-FCP was evaluated in vivo with detailed biodistribution studies and PET imaging in normal and KB 3-1 and KB 8-5 tumor xenograft bearing nude mice. The biodistribution studies and PET imaging of [18F]-FCP showed major uptake in kidneys which attributes to the renal clearance of radiotracer. In vivo plasma and urine stability demonstrated intact [18F]-FCP. [ 111In]-Labeled Liposomes was synthesized and physiochemical properties were assessed with DLS. [111In]-Labeled Liposome was evaluated in vivo with detailed pharmacokinetic studies and SPECT imaging. The biodistribution and ROI analysis from SPECT imaging showed the spleen and liver uptake of [111In]-Labeled Liposome and subsequent clearance of activity with time. [18F]-FCP encapsulated [111In]-Labeled Liposome was developed and physiochemical properties were characterized with DLS. [18F]-FCP encapsulated [111In]-Labeled Liposome was used for in vivo dual tracer PET and SPECT imaging from the same nanoconstruct in KB 3-1 (sensitive) and COLO 205 (resistant) tumor xenograft bearing nude mice. PET imaging of [18F]-FCP in KB 3-1 (sensitive) and COLO 205 (resistant) tumor xenograft bearing nude mice was performed. Naked [18F]-FCP and [18F]-FCP encapsulated [ 111In]-Labeled Liposome showed different pharmacokinetic profiles. PET imaging of [18F]-FCP showed major uptake in kidneys and bladder. However, [18F]-FCP encapsulated [111In]-Labeled Liposome showed major uptake in RES in both PET and SPECT images. ROI analysis of SPECT image enabled by 111In corresponded with PET image enabled by 18F demonstrating the feasibility of dual tracer imaging from the single nanoconstruct. Future work involves the intensive in vitro characterization of [18F]-FCP encapsulated [ 111In]-Labeled Liposome and detailed in vivo evaluation of [ 18F]-FCP encapsulated [111In]-Labeled Liposome in various tumor models.

Multimodal Molecular Imaging Reveals High Target Uptake and Specificity of 111In- and 68Ga-Labeled Fibrin-Binding Probes for Thrombus Detection in Rats.

PubMed

Oliveira, Bruno L; Blasi, Francesco; Rietz, Tyson A; Rotile, Nicholas J; Day, Helen; Caravan, Peter

2015-10-01

We recently showed the high target specificity and favorable imaging properties of 64Cu and Al18F PET probes for noninvasive imaging of thrombosis. Here, our aim was to evaluate new derivatives labeled with either with 68Ga, 111In, or 99mTc as thrombus imaging agents for PET and SPECT. In this study, the feasibility and potential of these probes for thrombus imaging was assessed in detail in 2 animal models of arterial thrombosis. The specificity of the probes was further evaluated using a triple-isotope approach with multimodal SPECT/PET/CT imaging. Radiotracers were synthesized using a known fibrin-binding peptide conjugated to 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid monoamide (DOTA-MA), or a diethylenetriamine ligand (DETA-propanoic acid [PA]), followed by labeling with 68Ga (FBP14, 68Ga-NODAGA), 111In (FBP15, 111In-DOTA-MA), or 99mTc (FBP16, 99mTc(CO)3-DETA-PA), respectively. PET or SPECT imaging, biodistribution, pharmacokinetics, and metabolic stability were evaluated in rat models of mural and occlusive carotid artery thrombosis. In vivo target specificity was evaluated by comparing the distribution of the SPECT and PET probes with preformed 125I-labeled thrombi and with a nonbinding control probe using SPECT/PET/CT imaging. All 3 radiotracers showed affinity similar to soluble fibrin fragment DD(E) (inhibition constant=0.53-0.83 μM). After the kidneys, the highest uptake of 68Ga-FBP14 and 111In-FBP15 was in the thrombus (1.0±0.2 percentage injected dose per gram), with low off-target accumulation. Both radiotracers underwent fast systemic elimination (half-life, 8-15 min) through the kidneys, which led to highly conspicuous thrombi on PET and SPECT images. 99mTc-FBP16 displayed low target uptake and distribution consistent with aggregation or degradation. Triple-isotope imaging experiments showed that both 68Ga-FBP14 and 111In-FBP15, but not the nonbinding derivative 64Cu-D-Cys-FBP8, detected the location of the 125I-labeled thrombus, confirming high target specificity. 68Ga-FBP14 and 111In-FBP15 have high fibrin affinity and thrombus specificity and represent useful PET and SPECT probes for thrombus detection. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Can DCE-MRI Explain the Heterogeneity in Radiopeptide Uptake Imaged by SPECT in a Pancreatic Neuroendocrine Tumor Model?

PubMed Central

Groen, Harald C.; Niessen, Wiro J.; Bernsen, Monique R.; de Jong, Marion; Veenland, Jifke F.

2013-01-01

Although efficient delivery and distribution of treatment agents over the whole tumor is essential for successful tumor treatment, the distribution of most of these agents cannot be visualized. However, with single-photon emission computed tomography (SPECT), both delivery and uptake of radiolabeled peptides can be visualized in a neuroendocrine tumor model overexpressing somatostatin receptors. A heterogeneous peptide uptake is often observed in these tumors. We hypothesized that peptide distribution in the tumor is spatially related to tumor perfusion, vessel density and permeability, as imaged and quantified by DCE-MRI in a neuroendocrine tumor model. Four subcutaneous CA20948 tumor-bearing Lewis rats were injected with the somatostatin-analog 111In-DTPA-Octreotide (50 MBq). SPECT-CT and MRI scans were acquired and MRI was spatially registered to SPECT-CT. DCE-MRI was analyzed using semi-quantitative and quantitative methods. Correlation between SPECT and DCE-MRI was investigated with 1) Spearman’s rank correlation coefficient; 2) SPECT uptake values grouped into deciles with corresponding median DCE-MRI parametric values and vice versa; and 3) linear regression analysis for median parameter values in combined datasets. In all tumors, areas with low peptide uptake correlated with low perfusion/density/ /permeability for all DCE-MRI-derived parameters. Combining all datasets, highest linear regression was found between peptide uptake and semi-quantitative parameters (R2>0.7). The average correlation coefficient between SPECT and DCE-MRI-derived parameters ranged from 0.52-0.56 (p<0.05) for parameters primarily associated with exchange between blood and extracellular extravascular space. For these parameters a linear relation with peptide uptake was observed. In conclusion, the ‘exchange-related’ DCE-MRI-derived parameters seemed to predict peptide uptake better than the ‘contrast amount- related’ parameters. Consequently, fast and efficient diffusion through the vessel wall into tissue is an important factor for peptide delivery. DCE-MRI helps to elucidate the relation between vascular characteristics, peptide delivery and treatment efficacy, and may form a basis to predict targeting efficiency. PMID:24116203

Comparison of Dynamic Contrast Enhanced MRI and Quantitative SPECT in a Rat Glioma Model

PubMed Central

Skinner, Jack T.; Yankeelov, Thomas E.; Peterson, Todd E.; Does, Mark D.

2012-01-01

Pharmacokinetic modeling of dynamic contrast enhanced (DCE)-MRI data provides measures of the extracellular volume fraction (ve) and the volume transfer constant (Ktrans) in a given tissue. These parameter estimates may be biased, however, by confounding issues such as contrast agent and tissue water dynamics, or assumptions of vascularization and perfusion made by the commonly used model. In contrast to MRI, radiotracer imaging with SPECT is insensitive to water dynamics. A quantitative dual-isotope SPECT technique was developed to obtain an estimate of ve in a rat glioma model for comparison to the corresponding estimates obtained using DCE-MRI with a vascular input function (VIF) and reference region model (RR). Both DCE-MRI methods produced consistently larger estimates of ve in comparison to the SPECT estimates, and several experimental sources were postulated to contribute to these differences. PMID:22991315

Diagnostic role of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for early and atypical bone metastases.

PubMed

Chen, Xiao-Liang; Li, Qian; Cao, Lin; Jiang, Shi-Xi

2014-01-01

The bone metastasis appeared early before the bone imaging for most of the above patients. (99)Tc(m)-MDP ((99)Tc(m) marked methylene diphosphonate) bone imaging could diagnosis the bone metastasis with highly sensitivity, but with lower specificity. The aim of this study is to explore the diagnostic value of (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging for the early period atypical bone metastases. 15 to 30 mCi (99)Tc(m)-MDP was intravenously injected to the 34 malignant patients diagnosed as doubtful early bone metastases. SPECT, CT and SPECT/CT images were captured and analyzed consequently. For the patients diagnosed as early period atypical bone metastases by SPECT/CT, combining the SPECT/CT and MRI together as the SPECT/MRI integrated image. The obtained SPECT/MRI image was analyzed and compared with the pathogenic results of patients. The results indicated that 34 early period doubtful metastatic focus, including 34 SPECT positive focus, 17 focus without special changes by using CT method, 11 bone metastases focus by using SPECT/CT method, 23 doubtful bone metastases focus, 8 doubtful bone metastases focus, 14 doubtful bone metastases focus and 2 focus without clear image. Totally, SPECT/CT combined with SPECT/MRI method diagnosed 30 bone metastatic focus and 4 doubtfully metastatic focus. In conclusion, (99)Tc(m)-MDP SPECT/CT combined SPECT/MRI Multi modality imaging shows a higher diagnostic value for the early period bone metastases, which also enhances the diagnostic accuracy rate.

Technetium glucose complexes as potential cancer imaging agents.

PubMed

Dapueto, Rosina; Aguiar, Rodrigo B; Moreno, María; Machado, Camila M L; Marques, Fabio L N; Gambini, Juan P; Chammas, Roger; Cabral, Pablo; Porcal, Williams

2015-10-01

GLUT's (facilitative glucose transporters) over-expression in tumor cells has allowed the detection of several cancer types, using a glucose analogue ((18)F-FDG) with PET images, worldwide. New glucose analogs radiolabeled with (99m)Tc could be a less-expensive and more accessible alternative for diagnosis using SPECT imaging. d-Glucose ((99m)Tc-IDAG) and 2-d-deoxyglucose ((99m)Tc-AADG) organometallic complexes were proposed and studied as potential (18)F-FDG surrogates. The glucose complexes were prepared and evaluated as potential cancer imaging agents, in a melanoma tumor model. Iminodiacetic acid (IDA) and aminoacetate (AA) moieties were chosen as chelating system for radiolabeling with (99m)Tc. Tumor uptake of the formed complexes was evaluated in B16 murine cell line in vitro and in vivo in melanoma bearing C57BL/6 mice. In vitro and in vivo studies were conducted with (18)F-FDG in order to compare the uptake of (99m)Tc-glucose complexes in the tumor model. IDAG and AADG compounds were synthesized and radiolabeled with (99m)TcO4(-) to obtain the (99m)Tc-IDAG and (99m)Tc-AADG complexes in high yield and stability. In vitro cell studies showed maximum uptake at 60 min for complexes, (99m)Tc-IDAG and (99m)Tc-AADG, with 6% and 2%, respectively. Biodistribution studies showed high tumor uptake one hour post-injection, reaching tumor-to-muscle ratios of 12.1 ± 3.73 and 2.88 ± 1.40 for (99m)Tc-IDAG and (99m)Tc-AADG, respectively. SPECT and micro-SPECT-CT images acquired after the injection of (99m)Tc-IDAG showed accumulation in tumor sites, suggesting that this glucose complex would be a promising candidate for cancer imaging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of image quality, myocardial perfusion, and LV function between standard imaging and single-injection ultra-low-dose imaging using a high-efficiency SPECT camera: the MILLISIEVERT study

PubMed Central

Einstein, Andrew J.; Blankstein, Ron; Andrews, Howard; Fish, Mathews; Padgett, Richard; Hayes, Sean W.; Friedman, John D.; Qureshi, Mehreen; Rakotoarivelo, Harivony; Slomka, Piotr; Nakazato, Ryo; Bokhari, Sabahat; Di Carli, Marcello; Berman, Daniel S.

2015-01-01

SPECT myocardial perfusion imaging (MPI) plays a central role in coronary artery disease diagnosis; but concerns exist regarding its radiation burden. Compared to standard Anger-SPECT (A-SPECT) cameras, new high-efficiency (HE) cameras with specialized collimators and solid-state cadmium-zinc-telluride detectors offer potential to maintain image quality (IQ), while reducing administered activity and thus radiation dose to patients. No previous study has compared IQ, interpretation, total perfusion deficit (TPD), or ejection fraction (EF) in patients receiving both ultra-low-dose (ULD) imaging on a HE-SPECT camera and standard low-dose (SLD) A-SPECT imaging. Methods We compared ULD-HE-SPECT to SLD-A-SPECT imaging by dividing the rest dose in 101 patients at 3 sites scheduled to undergo clinical A-SPECT MPI using a same day rest/stress Tc-99m protocol. Patients received HE-SPECT imaging following an initial ~130 MBq (3.5mCi) dose, and SLD-A-SPECT imaging following the remainder of the planned dose. Images were scored visually by 2 blinded readers for IQ and summed rest score (SRS). TPD and EF were assessed quantitatively. Results Mean activity was 134 MBq (3.62 mCi) for ULD-HE-SPECT (effective dose 1.15 mSv) and 278 MBq (7.50 mCi, 2.39 mSv) for SLD-A-SPECT. Overall IQ was superior for ULD-HE-SPECT (p<0.0001), with twice as many studies graded excellent quality. Extracardiac activity and overall perfusion assessment were similar. Between-method correlations were high for SRS (r=0.87), TPD (r=0.91), and EF (r=0.88). Conclusion ULD-HE-SPECT rest imaging correlates highly with SLD-A-SPECT. It has improved image quality, comparable extracardiac activity, and achieves radiation dose reduction to 1 mSv for a single injection. PMID:24982439

The bone scan.

PubMed

Brenner, Arnold I; Koshy, June; Morey, Jose; Lin, Cheryl; DiPoce, Jason

2012-01-01

Bone imaging continues to be the second greatest-volume nuclear imaging procedure, offering the advantage of total body examination, low cost, and high sensitivity. Its power rests in the physiological uptake and pathophysiologic behavior of 99m technetium (99m-Tc) diphosphonates. The diagnostic utility, sensitivity, specificity, and predictive value of 99m-Tc bone imaging for benign conditions and tumors was established when only planar imaging was available. Currently, nearly all bone scans are performed as a planar study (whole-body, 3-phase, or regional), with the radiologist often adding single-photon emission computed tomography (SPECT) imaging. Here we review many current indications for planar bone imaging, highlighting indications in which the planar data are often diagnostically sufficient, although diagnosis may be enhanced by SPECT. (18)F sodium fluoride positron emission tomography (PET) is also re-emerging as a bone agent, and had been considered interchangeable with 99m-Tc diphosphonates in the past. In addition to SPECT, new imaging modalities, including (18)F fluorodeoxyglucose, PET/CT, CT, magnetic resonance, and SPECT/CT, have been developed and can aid in evaluating benign and malignant bone disease. Because (18)F fluorodeoxyglucose is taken up by tumor cells and Tc diphosphonates are taken up in osteoblastic activity or osteoblastic healing reaction, both modalities are complementary. CT and magnetic resonance may supplement, but do not replace, bone imaging, which often detects pathology before anatomic changes are appreciated. We also stress the importance of dose reduction by reducing the dose of 99m-Tc diphosphonates and avoiding unnecessary CT acquisitions. In addition, we describe an approach to image interpretation that emphasizes communication with referring colleagues and correlation with appropriate history to significantly improve our impact on patient care. Copyright © 2012 Elsevier Inc. All rights reserved.

Synthesis of 4-substituted-trans-1,2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and spect and pet imaging

DOEpatents

Mease, Ronnie C.; Kolsky, Kathryn L.; Mausner, Leonard F.; Srivastava, Suresh C.

1997-06-03

Cyclohexyl chelating agents useful in forming antibody-metal conjugates useful for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N, N, N', N'-tetra acetic acid.

Synthesis of 4-substituted-trans-1, 2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and spect and pet imaging

DOEpatents

Mease, Ronnie C.; Mausner, Leonard F.; Srivastava, Suresh C.

1994-01-01

Cyclo agents useful in forming antibody-metal conjugates useful for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N,N,N',N'-tetra acetic acid.

On the use of superparamagnetic hydroxyapatite nanoparticles as an agent for magnetic and nuclear in vivo imaging.

PubMed

Adamiano, Alessio; Iafisco, Michele; Sandri, Monica; Basini, Martina; Arosio, Paolo; Canu, Tamara; Sitia, Giovanni; Esposito, Antonio; Iannotti, Vincenzo; Ausanio, Giovanni; Fragogeorgi, Eirini; Rouchota, Maritina; Loudos, George; Lascialfari, Alessandro; Tampieri, Anna

2018-06-01

The identification of alternative biocompatible magnetic NPs for advanced clinical application is becoming an important need due to raising concerns about iron accumulation in soft issues associated to the administration of superparamagnetic iron oxide nanoparticles (NPs). Here, we report on the performance of previously synthetized iron-doped hydroxyapatite (FeHA) NPs as contrast agent for magnetic resonance imaging (MRI). The MRI contrast abilities of FeHA and Endorem® (dextran coated iron oxide NPs) were assessed by 1 H nuclear magnetic resonance relaxometry and their performance in healthy mice was monitored by a 7 Tesla scanner. FeHA applied a higher contrast enhancement, and had a longer endurance in the liver with respect to Endorem® at iron equality. Additionally, a proof of concept of FeHA use as scintigraphy imaging agent for positron emission tomography (PET) and single photon emission computed tomography (SPECT) was given labeling FeHA with 99m Tc-MDP by a straightforward surface functionalization process. Scintigraphy/x-ray fused imaging and ex vivo studies confirmed its dominant accumulation in the liver, and secondarily in other organs of the mononuclear phagocyte system. FeHA efficiency as MRI-T 2 and PET-SPECT imaging agent combined to its already reported intrinsic biocompatibility qualifies it as a promising material for innovative nanomedical applications. The ability of iron-doped hydroxyapatite nanoaprticles (FeHA) to work in vivo as imaging agents for magnetic resonance (MR) and nuclear imaging is demonstrated. FeHA applied an higher MR contrast in the liver, spleen and kidneys of mice with respect to Endorem®. The successful radiolabeling of FeHA allowed for scintigraphy/X-ray and ex vivo biodistribution studies, confirming MR results and envisioning FeHA application for dual-imaging. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Clinical results with beta-methyl-p-(123I)iodophenylpentadecanoic acid, single-photon emission computed tomography in cardiac disease.

PubMed

Nishimura, T; Uehara, T; Shimonagata, T; Nagata, S; Haze, K

1994-01-01

This study was undertaken to evaluate the relationships, between myocardial perfusion and metabolism. Simultaneous beta-methyl-p(123I)iodophenylpentadecanoic acid (123I-BMIPP) and thallium 201 myocardial single-photon emission computed tomography (SPECT) were performed in 25 patients with myocardial infarction (group A) and 16 patients with hypertrophic cardiomyopathy (group B). The severity scores of 123I-BMIPP and 201Tl myocardial SPECT images were evaluated semiquantitatively by segmental analysis. In Group A, dissociations between thallium- and 123I-BMIPP-imaged defects were frequently observed in patients with successful reperfusion compared with those with no reperfusion and those with reinfarction. In four patients with successful reperfusion, repeated 123I-BMIPP and 201Tl myocardial SPECT showed gradual improvement of the 123I-BMIPP severity score compared with the thallium severity score. In group B, dissociations between thallium- and 123I-BMIPP-imaged defects were also demonstrated in hypertrophic myocardium. In addition, nonhypertrophic myocardium also had decreased 123I-BMIPP uptake. In groups A and B, 123I-BMIPP severity scores correlated well with left ventricular function compared with thallium severity scores. These findings indicate that 123I-BMIPP is a suitable agent for the assessment of functional integrity, because left ventricular wall motion is energy dependent and 123I-BMIPP may reflect an aspect of myocardial energy production. This agent may be useful for the early detection and patient management of various heart diseases as an alternative to positron emission tomographic study.

A Multimodal Imaging Protocol, (123)I/(99)Tc-Sestamibi, SPECT, and SPECT/CT, in Primary Hyperparathyroidism Adds Limited Benefit for Preoperative Localization.

PubMed

Lee, Grace S; McKenzie, Travis J; Mullan, Brian P; Farley, David R; Thompson, Geoffrey B; Richards, Melanie L

2016-03-01

Focused parathyroidectomy in primary hyperparathyroidism (1°HPT) is possible with accurate preoperative localization and intraoperative PTH monitoring (IOPTH). The added benefit of multimodal imaging techniques for operative success is unknown. Patients with 1°HPT, who underwent parathyroidectomy in 2012-2014 at a single institution, were retrospectively reviewed. Only the patients who underwent the standardized multimodal imaging workup consisting of (123)I/(99)Tc-sestamibi subtraction scintigraphy, SPECT, and SPECT/CT were assessed. Of 360 patients who were identified, a curative operation was performed in 96%, using pre-operative imaging and IOPTH. Imaging analysis showed that (123)I/(99)Tc-sestamibi had a sensitivity of 86% (95% CI 82-90%), positive predictive value (PPV) 93%, and accuracy 81%, based on correct lateralization. SPECT had a sensitivity of 77% (95% CI 72-82%), PPV 92% and accuracy 72%. SPECT/CT had a sensitivity of 75% (95% CI 70-80%), PPV of 94%, and accuracy 71%. There were 3 of 45 (7%) patients with negative sestamibi imaging that had an accurate SPECT and SPECT/CT. Of 312 patients (87%) with positive uptake on sestamibi (93% true positive, 7% false positive), concordant findings were present in 86% SPECT and 84% SPECT/CT. In cases where imaging modalities were discordant, but at least one method was true-positive, (123)I/(99)Tc-sestamibi was significantly better than both SPECT and SPECT/CT (p < 0.001). The inclusion of SPECT and SPECT/CT in 1°HPT imaging protocol increases patient cost up to 2.4-fold. (123)I/(99)Tc-sestamibi subtraction imaging is highly sensitive for preoperative localization in 1°HPT. SPECT and SPECT/CT are commonly concordant with (123)I/(99)Tc-sestamibi and rarely increase the sensitivity. Routine inclusion of multimodality imaging technique adds minimal clinical benefit but increases cost to patient in high-volume setting.

MicroSPECT imaging of triple negative breast cancer cell tumor xenografted in athymic mice with radioiodinated anti-ICAM-1 monoclonal antibody.

PubMed

You, Linyi; Wang, Xiangyu; Guo, Zhide; Zhang, Deliang; Zhang, Pu; Li, Jindian; Su, Xinhui; Pan, Weimin; Zhang, Xianzhong

2018-04-04

Intercellular adhesion molecule-1(ICAM-1) is a potential molecular target and biomarker for triple negative breast cancer (TNBC) therapy and diagnosis. In this study, aICAM-1 was radioiodinated with 125 I/ 131 I in high radiochemical yield and the probes for TNBC tumor targeting and radioimmunotherapy were evaluated in tumor-bearing mice. High and specific accumulation of 125 I-aICAM1 in TNBC MDA-MB-231 tumor was observed in SPECT imaging and the tumor grew was inhibited obviously by 131 I-aICAM1. Thus, the radioiodinated aICAM1 could serve as potential agents for TNBC theranostics. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Clinical applications of molecular imaging methods for patients with ischemic stroke].

PubMed

Yamauchi, Hiroshi; Fukuyama, Hidenao

2007-02-01

Several molecular imaging methods have been developed to visualize pathophysiology of cerebral ischemia in humans in vivo. PET and SPECT with specific ligands have been mainly used as diagnostic tools for the clinical usage of molecular imaging in patients with ischemic stroke. Recently, cellular MR imaging with specific contrast agents has been developed to visualize targeted cells in human stroke patients. This article reviews the current status in the clinical applications of those molecular imaging methods for patients with ischemic stroke.

Simultaneous dual-radionuclide myocardial perfusion imaging with a solid-state dedicated cardiac camera.

PubMed

Ben-Haim, Simona; Kacperski, Krzysztof; Hain, Sharon; Van Gramberg, Dean; Hutton, Brian F; Erlandsson, Kjell; Sharir, Tali; Roth, Nathaniel; Waddington, Wendy A; Berman, Daniel S; Ell, Peter J

2010-08-01

We compared simultaneous dual-radionuclide (DR) stress and rest myocardial perfusion imaging (MPI) with a novel solid-state cardiac camera and a conventional SPECT camera with separate stress and rest acquisitions. Of 27 consecutive patients recruited, 24 (64.5+/-11.8 years of age, 16 men) were injected with 74 MBq of (201)Tl (rest) and 250 MBq (99m)Tc-MIBI (stress). Conventional MPI acquisition times for stress and rest are 21 min and 16 min, respectively. Rest (201)Tl for 6 min and simultaneous DR 15-min list mode gated scans were performed on a D-SPECT cardiac scanner. In 11 patients DR D-SPECT was performed first and in 13 patients conventional stress (99m)Tc-MIBI SPECT imaging was performed followed by DR D-SPECT. The DR D-SPECT data were processed using a spill-over and scatter correction method. DR D-SPECT images were compared with rest (201)Tl D-SPECT and with conventional SPECT images by visual analysis employing the 17-segment model and a five-point scale (0 normal, 4 absent) to calculate the summed stress and rest scores. Image quality was assessed on a four-point scale (1 poor, 4 very good) and gut activity was assessed on a four-point scale (0 none, 3 high). Conventional MPI studies were abnormal at stress in 17 patients and at rest in 9 patients. In the 17 abnormal stress studies DR D-SPECT MPI showed 113 abnormal segments and conventional MPI showed 93 abnormal segments. In the nine abnormal rest studies DR D-SPECT showed 45 abnormal segments and conventional MPI showed 48 abnormal segments. The summed stress and rest scores on conventional SPECT and DR D-SPECT were highly correlated (r=0.9790 and 0.9694, respectively). The summed scores of rest (201)Tl D-SPECT and DR-DSPECT were also highly correlated (r=0.9968, p<0.0001 for all). In six patients stress perfusion defects were significantly larger on stress DR D-SPECT images, and five of these patients were imaged earlier by D-SPECT than by conventional SPECT. Fast and high-quality simultaneous DR MPI is feasible with D-SPECT in a single imaging session with comparable diagnostic performance and image quality to conventional SPECT and to a separate rest (201)Tl D-SPECT acquisition.

Recent trends in soft-tissue infection imaging.

PubMed

Petruzzi, Nicholas; Shanthly, Nylla; Thakur, Mathew

2009-03-01

This article discusses the current techniques and future directions of infection imaging with particular attention to respiratory, central nervous system, abdominal, and postoperative infections. The agents currently in use localize to areas of infection and inflammation. An infection-specific imaging agent would greatly improve the utility of scintigraphy in imaging occult infections. The superior spatial resolution of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) and its lack of reliance on a functional immune system, gives this agent certain advantages over the other radiopharmaceuticals. In respiratory tract infection imaging, an important advancement would be the ability to quantitatively delineate lung inflammation, allowing one to monitor the therapeutic response in a variety of conditions. Current studies suggest PET should be considered the most accurate quantitative method. Scintigraphy has much to offer in localizing abdominal infection as well as inflammation. We may begin to see a gradual increase in the usage of (18)F-FDG-PET in detecting occult abdominal infections. Commonly used modalities for imaging inflammatory bowel disease are scintigraphy with (111)In-oxine/(99m)Tc-HMPAO labeled autologous white blood cells. The literature on central nervous system infection imaging is relatively scarce. Few clinical studies have been performed and numerous new agents have been developed for this use with varying results. Further studies are needed to more clearly delineate the future direction of this field. In evaluating the postoperative spine, (99m)Tc-ciprofloxacin single-photon emission computed tomography (SPECT) was reported to be >80% sensitive in patients more than 6 months after surgery. FDG-PET has also been suggested for this purpose and may play a larger role than originally thought. It appears PET/computed tomography (CT) is gaining support, especially in imaging those with fever of unknown origin or nonfunctional immune systems. Although an infection-specific agent is lacking, the development of one would greatly advance our ability to detect, localize, and quantify infections. Overall, imaging such an agent via SPECT/CT or PET/CT will pave the way for greater clinical reliability in the localization of infection.

Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT

NASA Astrophysics Data System (ADS)

Liu, Hui; Chan, Chung; Grobshtein, Yariv; Ma, Tianyu; Liu, Yaqiang; Wang, Shi; Stacy, Mitchel R.; Sinusas, Albert J.; Liu, Chi

2015-09-01

Due to the limited spatial resolution, partial volume effect has been a major degrading factor on quantitative accuracy in emission tomography systems. This study aims to investigate the performance of several anatomical-based partial volume correction (PVC) methods for a dedicated cardiac SPECT/CT system (GE Discovery NM/CT 570c) with focused field-of-view over a clinically relevant range of high and low count levels for two different radiotracer distributions. These PVC methods include perturbation geometry transfer matrix (pGTM), pGTM followed by multi-target correction (MTC), pGTM with known concentration in blood pool, the former followed by MTC and our newly proposed methods, which perform the MTC method iteratively, where the mean values in all regions are estimated and updated by the MTC-corrected images each time in the iterative process. The NCAT phantom was simulated for cardiovascular imaging with 99mTc-tetrofosmin, a myocardial perfusion agent, and 99mTc-red blood cell (RBC), a pure intravascular imaging agent. Images were acquired at six different count levels to investigate the performance of PVC methods in both high and low count levels for low-dose applications. We performed two large animal in vivo cardiac imaging experiments following injection of 99mTc-RBC for evaluation of intramyocardial blood volume (IMBV). The simulation results showed our proposed iterative methods provide superior performance than other existing PVC methods in terms of image quality, quantitative accuracy, and reproducibility (standard deviation), particularly for low-count data. The iterative approaches are robust for both 99mTc-tetrofosmin perfusion imaging and 99mTc-RBC imaging of IMBV and blood pool activity even at low count levels. The animal study results indicated the effectiveness of PVC to correct the overestimation of IMBV due to blood pool contamination. In conclusion, the iterative PVC methods can achieve more accurate quantification, particularly for low count cardiac SPECT studies, typically obtained from low-dose protocols, gated studies, and dynamic applications.

Ventilation/perfusion SPECT or SPECT/CT for lung function imaging in patients with pulmonary emphysema?

PubMed

Froeling, Vera; Heimann, Uwe; Huebner, Ralf-Harto; Kroencke, Thomas J; Maurer, Martin H; Doellinger, Felix; Geisel, Dominik; Hamm, Bernd; Brenner, Winfried; Schreiter, Nils F

2015-07-01

To evaluate the utility of attenuation correction (AC) of V/P SPECT images for patients with pulmonary emphysema. Twenty-one patients (mean age 67.6 years) with pulmonary emphysema who underwent V/P SPECT/CT were included. AC/non-AC V/P SPECT images were compared visually and semiquantitatively. Visual comparison of AC/non-AC images was based on a 5-point likert scale. Semiquantitative comparison assessed absolute counts per lung (aCpLu) and lung lobe (aCpLo) for AC/non-AC images using software-based analysis; percentage counts (PC = (aCpLo/aCpLu) × 100) were calculated. Correlation between AC/non-AC V/P SPECT images was analyzed using Spearman's rho correlation coefficient; differences were tested for significance with the Wilcoxon rank sum test. Visual analysis revealed high conformity for AC and non-AC V/P SPECT images. Semiquantitative analysis of PC in AC/non-AC images had an excellent correlation and showed no significant differences in perfusion (ρ = 0.986) or ventilation (ρ = 0.979, p = 0.809) SPECT/CT images. AC of V/P SPECT images for lung lobe-based function imaging in patients with pulmonary emphysema do not improve visual or semiquantitative image analysis.

The AdaptiSPECT Imaging Aperture

PubMed Central

Chaix, Cécile; Moore, Jared W.; Van Holen, Roel; Barrett, Harrison H.; Furenlid, Lars R.

2015-01-01

In this paper, we present the imaging aperture of an adaptive SPECT imaging system being developed at the Center for Gamma Ray Imaging (AdaptiSPECT). AdaptiSPECT is designed to automatically change its configuration in response to preliminary data, in order to improve image quality for a particular task. In a traditional pinhole SPECT imaging system, the characteristics (magnification, resolution, field of view) are set by the geometry of the system, and any modification can be accomplished only by manually changing the collimator and the distance of the detector to the center of the field of view. Optimization of the imaging system for a specific task on a specific individual is therefore difficult. In an adaptive SPECT imaging system, on the other hand, the configuration can be conveniently changed under computer control. A key component of an adaptive SPECT system is its aperture. In this paper, we present the design, specifications, and fabrication of the adaptive pinhole aperture that will be used for AdaptiSPECT, as well as the controls that enable autonomous adaptation. PMID:27019577

Three modality image registration of brain SPECT/CT and MR images for quantitative analysis of dopamine transporter imaging

NASA Astrophysics Data System (ADS)

Yamaguchi, Yuzuho; Takeda, Yuta; Hara, Takeshi; Zhou, Xiangrong; Matsusako, Masaki; Tanaka, Yuki; Hosoya, Kazuhiko; Nihei, Tsutomu; Katafuchi, Tetsuro; Fujita, Hiroshi

2016-03-01

Important features in Parkinson's disease (PD) are degenerations and losses of dopamine neurons in corpus striatum. 123I-FP-CIT can visualize activities of the dopamine neurons. The activity radio of background to corpus striatum is used for diagnosis of PD and Dementia with Lewy Bodies (DLB). The specific activity can be observed in the corpus striatum on SPECT images, but the location and the shape of the corpus striatum on SPECT images only are often lost because of the low uptake. In contrast, MR images can visualize the locations of the corpus striatum. The purpose of this study was to realize a quantitative image analysis for the SPECT images by using image registration technique with brain MR images that can determine the region of corpus striatum. In this study, the image fusion technique was used to fuse SPECT and MR images by intervening CT image taken by SPECT/CT. The mutual information (MI) for image registration between CT and MR images was used for the registration. Six SPECT/CT and four MR scans of phantom materials are taken by changing the direction. As the results of the image registrations, 16 of 24 combinations were registered within 1.3mm. By applying the approach to 32 clinical SPECT/CT and MR cases, all of the cases were registered within 0.86mm. In conclusions, our registration method has a potential in superimposing MR images on SPECT images.

System Integration of FastSPECT III, a Dedicated SPECT Rodent-Brain Imager Based on BazookaSPECT Detector Technology

PubMed Central

Miller, Brian W.; Furenlid, Lars R.; Moore, Stephen K.; Barber, H. Bradford; Nagarkar, Vivek V.; Barrett, Harrison H.

2010-01-01

FastSPECT III is a stationary, single-photon emission computed tomography (SPECT) imager designed specifically for imaging and studying neurological pathologies in rodent brain, including Alzheimer’s and Parkinsons’s disease. Twenty independent BazookaSPECT [1] gamma-ray detectors acquire projections of a spherical field of view with pinholes selected for desired resolution and sensitivity. Each BazookaSPECT detector comprises a columnar CsI(Tl) scintillator, image-intensifier, optical lens, and fast-frame-rate CCD camera. Data stream back to processing computers via firewire interfaces, and heavy use of graphics processing units (GPUs) ensures that each frame of data is processed in real time to extract the images of individual gamma-ray events. Details of the system design, imaging aperture fabrication methods, and preliminary projection images are presented. PMID:21218137

MR-based keyhole SPECT for small animal imaging

PubMed Central

Lee, Keum Sil; Roeck, Werner W; Gullberg, Grant T; Nalcioglu, Orhan

2011-01-01

The rationale for multi-modality imaging is to integrate the strengths of different imaging technologies while reducing the shortcomings of an individual modality. The work presented here proposes a limited-field-of-view (LFOV) SPECT reconstruction technique that can be implemented on a multi-modality MR/SPECT system that can be used to obtain simultaneous MRI and SPECT images for small animal imaging. The reason for using a combined MR/SPECT system in this work is to eliminate any possible misregistration between the two sets of images when MR images are used as a priori information for SPECT. In nuclear imaging the target area is usually smaller than the entire object; thus, focusing the detector on the LFOV results in various advantages including the use of a smaller nuclear detector (less cost), smaller reconstruction region (faster reconstruction) and higher spatial resolution when used in conjunction with pinhole collimators with magnification. The MR/SPECT system can be used to choose a region of interest (ROI) for SPECT. A priori information obtained by the full field-of-view (FOV) MRI combined with the preliminary SPECT image can be used to reduce the dimensions of the SPECT reconstruction by limiting the computation to the smaller FOV while reducing artifacts resulting from the truncated data. Since the technique is based on SPECT imaging within the LFOV it will be called the keyhole SPECT (K-SPECT) method. At first MRI images of the entire object using a larger FOV are obtained to determine the location of the ROI covering the target organ. Once the ROI is determined, the animal is moved inside the radiofrequency (rf) coil to bring the target area inside the LFOV and then simultaneous MRI and SPECT are performed. The spatial resolution of the SPECT image is improved by employing a pinhole collimator with magnification >1 by having carefully calculated acceptance angles for each pinhole to avoid multiplexing. In our design all the pinholes are focused to the center of the LFOV. K-SPECT reconstruction is accomplished by generating an adaptive weighting matrix using a priori information obtained by simultaneously acquired MR images and the radioactivity distribution obtained from the ROI region of the SPECT image that is reconstructed without any a priori input. Preliminary results using simulations with numerical phantoms show that the image resolution of the SPECT image within the LFOV is improved while minimizing artifacts arising from parts of the object outside the LFOV due to the chosen magnification and the new reconstruction technique. The root-mean-square-error (RMSE) in the out-of-field artifacts was reduced by 60% for spherical phantoms using the K-SPECT reconstruction technique and by 48.5–52.6% for the heart in the case with the MOBY phantom. The KSPECT reconstruction technique significantly improved the spatial resolution and quantification while reducing artifacts from the contributions outside the LFOV as well as reducing the dimension of the reconstruction matrix. PMID:21220840

Molecular imaging in drug development: Update and challenges for radiolabeled antibodies and nanotechnology.

PubMed

Colombo, Ilaria; Overchuk, Marta; Chen, Juan; Reilly, Raymond M; Zheng, Gang; Lheureux, Stephanie

2017-11-01

Despite the significant advancement achieved in understanding the molecular mechanisms responsible for cancer transformation and aberrant proliferation, leading to novel targeted cancer therapies, significant effort is still needed to "personalize" cancer treatment. Molecular imaging is an emerging field that has shown the ability to characterize in vivo the molecular pathways present at the cancer cell level, enabling diagnosis and personalized treatment of malignancies. These technologies, particularly SPECT and PET also permit the development of novel radiotheranostic probes, which provide capabilities for diagnosis and treatment with the same agent. The small therapeutic index of most anticancer agents is a limitation in the drug development process. Incorporation of molecular imaging in clinical research may help in overcoming this limitation and favouring selection of patient populations most likely to achieve benefit from targeted therapy. This review will focus on two of the most advanced theranostic approaches with promising potential for application in the clinic: 1) therapeutic monoclonal antibodies which may be linked to a radionuclide for SPECT or PET imaging to guide cancer diagnosis, staging, molecular characterization, and assessment of the response to treatment and 2) multifunctional nanotechnology that allows image guided drug delivery through encapsulation of multiple therapeutic, targeting and imaging agents into a single nanoparticle. Porphysome, a liposome-like nanoparticle, is an example of a novel and promising application of nanotechnology for cancer diagnosis and treatment. These technologies have proven to be effective in preclinical models, warranting further clinical investigation to advance their application for the benefit of cancer patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Generalized paired-agent kinetic model for in vivo quantification of cancer cell-surface receptors under receptor saturation conditions

NASA Astrophysics Data System (ADS)

Sadeghipour, N.; Davis, S. C.; Tichauer, K. M.

2017-01-01

New precision medicine drugs oftentimes act through binding to specific cell-surface cancer receptors, and thus their efficacy is highly dependent on the availability of those receptors and the receptor concentration per cell. Paired-agent molecular imaging can provide quantitative information on receptor status in vivo, especially in tumor tissue; however, to date, published approaches to paired-agent quantitative imaging require that only ‘trace’ levels of imaging agent exist compared to receptor concentration. This strict requirement may limit applicability, particularly in drug binding studies, which seek to report on a biological effect in response to saturating receptors with a drug moiety. To extend the regime over which paired-agent imaging may be used, this work presents a generalized simplified reference tissue model (GSRTM) for paired-agent imaging developed to approximate receptor concentration in both non-receptor-saturated and receptor-saturated conditions. Extensive simulation studies show that tumor receptor concentration estimates recovered using the GSRTM are more accurate in receptor-saturation conditions than the standard simple reference tissue model (SRTM) (% error (mean  ±  sd): GSRTM 0  ±  1 and SRTM 50  ±  1) and match the SRTM accuracy in non-saturated conditions (% error (mean  ±  sd): GSRTM 5  ±  5 and SRTM 0  ±  5). To further test the approach, GSRTM-estimated receptor concentration was compared to SRTM-estimated values extracted from tumor xenograft in vivo mouse model data. The GSRTM estimates were observed to deviate from the SRTM in tumors with low receptor saturation (which are likely in a saturated regime). Finally, a general ‘rule-of-thumb’ algorithm is presented to estimate the expected level of receptor saturation that would be achieved in a given tissue provided dose and pharmacokinetic information about the drug or imaging agent being used, and physiological information about the tissue. These studies suggest that the GSRTM is necessary when receptor saturation exceeds 20% and highlight the potential for GSRTM to accurately measure receptor concentrations under saturation conditions, such as might be required during high dose drug studies, or for imaging applications where high concentrations of imaging agent are required to optimize signal-to-noise conditions. This model can also be applied to PET and SPECT imaging studies that tend to suffer from noisier data, but require one less parameter to fit if images are converted to imaging agent concentration (quantitative PET/SPECT).

Synthesis of 4-substituted-trans-1, 2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and SPECT and PET imaging

DOEpatents

Mease, R.C.; Mausner, L.F.; Srivastava, S.C.

1994-03-08

Cyclo agents are described which are useful in forming antibody-metal conjugates which are used for diagnostic and therapeutic purposes. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2diamino cyclohexane-N,N,N',N'-tetra acetic acid. No Drawings

Synthesis of 4-substituted-trans-1,2-diaminocyclohexyl polyaminocarboxylate metal chelating agents for the preparation of stable radiometal antibody immunoconjugates for therapy and SPECT and PET imaging

DOEpatents

Mease, R.C.; Kolsky, K.L.; Mausner, L.F.; Srivastava, S.C.

1997-06-03

Cyclohexyl chelating agents useful in forming antibody-metal conjugates which are used for diagnostic and therapeutic purposes are synthesized. New compounds and processes of forming these compounds are disclosed including 4-haloacetamido-trans-1,2-diaminocyclohexyl polyaminocarboxylate and 4-isothiocyanato-trans-1,2-diamino cyclohexane-N,N,N{prime},N{prime}-tetra acetic acid.

Monte Carlo simulation of PET and SPECT imaging of {sup 90}Y

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Akihiko, E-mail: takahsr@hs.med.kyushu-u.ac.jp; Sasaki, Masayuki; Himuro, Kazuhiko

2015-04-15

Purpose: Yittrium-90 ({sup 90}Y) is traditionally thought of as a pure beta emitter, and is used in targeted radionuclide therapy, with imaging performed using bremsstrahlung single-photon emission computed tomography (SPECT). However, because {sup 90}Y also emits positrons through internal pair production with a very small branching ratio, positron emission tomography (PET) imaging is also available. Because of the insufficient image quality of {sup 90}Y bremsstrahlung SPECT, PET imaging has been suggested as an alternative. In this paper, the authors present the Monte Carlo-based simulation–reconstruction framework for {sup 90}Y to comprehensively analyze the PET and SPECT imaging techniques and to quantitativelymore » consider the disadvantages associated with them. Methods: Our PET and SPECT simulation modules were developed using Monte Carlo simulation of Electrons and Photons (MCEP), developed by Dr. S. Uehara. PET code (MCEP-PET) generates a sinogram, and reconstructs the tomography image using a time-of-flight ordered subset expectation maximization (TOF-OSEM) algorithm with attenuation compensation. To evaluate MCEP-PET, simulated results of {sup 18}F PET imaging were compared with the experimental results. The results confirmed that MCEP-PET can simulate the experimental results very well. The SPECT code (MCEP-SPECT) models the collimator and NaI detector system, and generates the projection images and projection data. To save the computational time, the authors adopt the prerecorded {sup 90}Y bremsstrahlung photon data calculated by MCEP. The projection data are also reconstructed using the OSEM algorithm. The authors simulated PET and SPECT images of a water phantom containing six hot spheres filled with different concentrations of {sup 90}Y without background activity. The amount of activity was 163 MBq, with an acquisition time of 40 min. Results: The simulated {sup 90}Y-PET image accurately simulated the experimental results. PET image is visually superior to SPECT image because of the low background noise. The simulation reveals that the detected photon number in SPECT is comparable to that of PET, but the large fraction (approximately 75%) of scattered and penetration photons contaminates SPECT image. The lower limit of {sup 90}Y detection in SPECT image was approximately 200 kBq/ml, while that in PET image was approximately 100 kBq/ml. Conclusions: By comparing the background noise level and the image concentration profile of both the techniques, PET image quality was determined to be superior to that of bremsstrahlung SPECT. The developed simulation codes will be very useful in the future investigations of PET and bremsstrahlung SPECT imaging of {sup 90}Y.« less

C-SPECT - a Clinical Cardiac SPECT/Tct Platform: Design Concepts and Performance Potential

PubMed Central

Chang, Wei; Ordonez, Caesar E.; Liang, Haoning; Li, Yusheng; Liu, Jingai

2013-01-01

Because of scarcity of photons emitted from the heart, clinical cardiac SPECT imaging is mainly limited by photon statistics. The sub-optimal detection efficiency of current SPECT systems not only limits the quality of clinical cardiac SPECT imaging but also makes more advanced potential applications difficult to be realized. We propose a high-performance system platform - C-SPECT, which has its sampling geometry optimized for detection of emitted photons in quality and quantity. The C-SPECT has a stationary C-shaped gantry that surrounds the left-front side of a patient’s thorax. The stationary C-shaped collimator and detector systems in the gantry provide effective and efficient detection and sampling of photon emission. For cardiac imaging, the C-SPECT platform could achieve 2 to 4 times the system geometric efficiency of conventional SPECT systems at the same sampling resolution. This platform also includes an integrated transmission CT for attenuation correction. The ability of C-SPECT systems to perform sequential high-quality emission and transmission imaging could bring cost-effective high-performance to clinical imaging. In addition, a C-SPECT system could provide high detection efficiency to accommodate fast acquisition rate for gated and dynamic cardiac imaging. This paper describes the design concepts and performance potential of C-SPECT, and illustrates how these concepts can be implemented in a basic system. PMID:23885129

Incremental value of 99mTc-HYNIC-TOC SPECT/CT over whole-body planar scintigraphy and SPECT in patients with neuroendocrine tumours.

PubMed

Trogrlic, Mate; Težak, Stanko

2017-06-12

The aim of this study was to evaluate the additional value of 99m Tc-HYNIC-TOC SPECT/CT over planar whole-body (WB) scintigraphy and SPECT alone in the detection and accurate localisation of neuroendocrine tumour (NET) lesions. This study included 65 patients with a definitive histological diagnosis of NET prior to scintigraphy. Planar WB scintigraphy, SPECT, and SPECT/CT images were acquired at 4 h post-administration of 670 MBq 99m Tc-HYNIC-TOC. Additional SPECT images at 10 min after tracer administration were also acquired. Clinical and imaging follow-up findings were considered as the reference standards (minimum follow-up period, 15 months). Patient and lesion-based analyses of the efficacies of the imaging modalities were performed. While 38 patients exhibited metastasis of NETs, 27 presented no evidence of metastasis. Upon patient-based analysis, the sensitivity and specificity of SPECT/CT were found to be 88.9 and 79.3 %, respectively. The diagnostic accuracies of WB scintigraphy, 4h-SPECT, and SPECT/CT were 72.3, 73.8, and 84.6 %, respectively. The area under curve (AUC) value for SPECT/CT (0.84) was the highest, followed by those for 4h-SPECT (0.75) and WB scintigraphy (0.74). The accuracy and AUC values of SPECT/CT were significantly better compared to those of WB scintigraphy (p < 0.001), 10 min-SPECT (p < 0.001), and 4 h-SPECT (p = 0.001). The findings of SPECT/CT led to the change in treatment plan of 11 patients (16.9 %). The sensitivity and diagnostic accuracy of SPECT/CT in the evaluation of NET lesions outperforms planar WB imaging or SPECT alone.

PCBs Alter Dopamine Mediated Function in Aging Workers

DTIC Science & Technology

2011-01-01

inhibitors, COX-2 inhibi- tors, other non - steroidal anti - inflammatory agents, opiate agonists, miscellaneous analgesics and antipyretics, thyroid...DA) similar to changes previously seen in PCB exposed adult non -human primates. To test that hypothesis we used [123I]β-CIT SPECT imaging to...adult non -human primates (Seegal et al., 1994a), also occur in occupationally exposed humans. In this study, we used in vivo molecular imaging of the

Imaging, autoradiography, and biodistribution of (188)Re-labeled PEGylated nanoliposome in orthotopic glioma bearing rat model.

PubMed

Huang, Feng-Yun J; Lee, Te-Wei; Kao, Chih-Hao K; Chang, Chih-Hsien; Zhang, Xiaoning; Lee, Wan-Yu; Chen, Wan-Jou; Wang, Shu-Chi; Lo, Jem-Mau

2011-12-01

The (188)Re-labeled pegylated nanoliposome (abbreviated as (188)Re-Liposome) was prepared and evaluated for its potential as a theragnostic agent for glioma. (188)Re-BMEDA complex was loaded into the pegylated liposome core with pH 5.5 ammonium sulfate gradient to produce (188)Re-Liposome. Orthotopic Fischer344/F98 glioma tumor-bearing rats were prepared and intravenously injected with (188)Re-Liposome. Biodistribution, pharmacokinetic study, autoradiography (ARG), histopathology, and nano-SPECT/CT imaging were conducted for the animal model. The result showed that (188)Re-Liposome accumulated in the brain tumor of the animal model from 0.28%±0.09% injected dose (ID)/g (n=3) at 1 hour to a maximum of 1.95%±0.35% ID/g (n=3) at 24 hours postinjection. The tumor-to-normal brain uptake ratio (T/N ratio) increased from 3.5 at 1 hour to 32.5 at 24 hours. Both ARG and histopathological images clearly showed corresponding tumor regions with high T/N ratios. Nano-SPECT/CT detected a very clear tumor image from 4 hours till 48 hours. This study reveals the potential of (188)Re-Liposome as a theragnostic agent for brain glioma.

A quantitative reconstruction software suite for SPECT imaging

NASA Astrophysics Data System (ADS)

Namías, Mauro; Jeraj, Robert

2017-11-01

Quantitative Single Photon Emission Tomography (SPECT) imaging allows for measurement of activity concentrations of a given radiotracer in vivo. Although SPECT has usually been perceived as non-quantitative by the medical community, the introduction of accurate CT based attenuation correction and scatter correction from hybrid SPECT/CT scanners has enabled SPECT systems to be as quantitative as Positron Emission Tomography (PET) systems. We implemented a software suite to reconstruct quantitative SPECT images from hybrid or dedicated SPECT systems with a separate CT scanner. Attenuation, scatter and collimator response corrections were included in an Ordered Subset Expectation Maximization (OSEM) algorithm. A novel scatter fraction estimation technique was introduced. The SPECT/CT system was calibrated with a cylindrical phantom and quantitative accuracy was assessed with an anthropomorphic phantom and a NEMA/IEC image quality phantom. Accurate activity measurements were achieved at an organ level. This software suite helps increasing quantitative accuracy of SPECT scanners.

Assessing Cardiac Injury in Mice With Dual Energy-MicroCT, 4D-MicroCT, and MicroSPECT Imaging After Partial Heart Irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Chang-Lung; Min, Hooney; Befera, Nicholas

Purpose: To develop a mouse model of cardiac injury after partial heart irradiation (PHI) and to test whether dual energy (DE)-microCT and 4-dimensional (4D)-microCT can be used to assess cardiac injury after PHI to complement myocardial perfusion imaging using micro-single photon emission computed tomography (SPECT). Methods and Materials: To study cardiac injury from tangent field irradiation in mice, we used a small-field biological irradiator to deliver a single dose of 12 Gy x-rays to approximately one-third of the left ventricle (LV) of Tie2Cre; p53{sup FL/+} and Tie2Cre; p53{sup FL/−} mice, where 1 or both alleles of p53 are deleted in endothelialmore » cells. Four and 8 weeks after irradiation, mice were injected with gold and iodinated nanoparticle-based contrast agents, and imaged with DE-microCT and 4D-microCT to evaluate myocardial vascular permeability and cardiac function, respectively. Additionally, the same mice were imaged with microSPECT to assess myocardial perfusion. Results: After PHI with tangent fields, DE-microCT scans showed a time-dependent increase in accumulation of gold nanoparticles (AuNp) in the myocardium of Tie2Cre; p53{sup FL/−} mice. In Tie2Cre; p53{sup FL/−} mice, extravasation of AuNp was observed within the irradiated LV, whereas in the myocardium of Tie2Cre; p53{sup FL/+} mice, AuNp were restricted to blood vessels. In addition, data from DE-microCT and microSPECT showed a linear correlation (R{sup 2} = 0.97) between the fraction of the LV that accumulated AuNp and the fraction of LV with a perfusion defect. Furthermore, 4D-microCT scans demonstrated that PHI caused a markedly decreased ejection fraction, and higher end-diastolic and end-systolic volumes, to develop in Tie2Cre; p53{sup FL/−} mice, which were associated with compensatory cardiac hypertrophy of the heart that was not irradiated. Conclusions: Our results show that DE-microCT and 4D-microCT with nanoparticle-based contrast agents are novel imaging approaches complementary to microSPECT for noninvasive assessment of the change in myocardial vascular permeability and cardiac function of mice in whom myocardial injury develops after PHI.« less

Novel multifunctional theranostic liposome drug delivery system: construction, characterization, and multimodality MR, near-infrared fluorescent, and nuclear imaging.

PubMed

Li, Shihong; Goins, Beth; Zhang, Lujun; Bao, Ande

2012-06-20

Liposomes are effective lipid nanoparticle drug delivery systems, which can also be functionalized with noninvasive multimodality imaging agents with each modality providing distinct information and having synergistic advantages in diagnosis, monitoring of disease treatment, and evaluation of liposomal drug pharmacokinetics. We designed and constructed a multifunctional theranostic liposomal drug delivery system, which integrated multimodality magnetic resonance (MR), near-infrared (NIR) fluorescent and nuclear imaging of liposomal drug delivery, and therapy monitoring and prediction. The premanufactured liposomes were composed of DSPC/cholesterol/Gd-DOTA-DSPE/DOTA-DSPE with the molar ratio of 39:35:25:1 and having ammonium sulfate/pH gradient. A lipidized NIR fluorescent tracer, IRDye-DSPE, was effectively postinserted into the premanufactured liposomes. Doxorubicin could be effectively postloaded into the multifunctional liposomes. The multifunctional doxorubicin-liposomes could also be stably radiolabeled with (99m)Tc or (64)Cu for single-photon emission computed tomography (SPECT) or positron emission tomography (PET) imaging, respectively. MR images displayed the high-resolution micro-intratumoral distribution of the liposomes in squamous cell carcinoma of head and neck (SCCHN) tumor xenografts in nude rats after intratumoral injection. NIR fluorescent, SPECT, and PET images also clearly showed either the high intratumoral retention or distribution of the multifunctional liposomes. This multifunctional drug carrying liposome system is promising for disease theranostics allowing noninvasive multimodality NIR fluorescent, MR, SPECT, and PET imaging of their in vivo behavior and capitalizing on the inherent advantages of each modality.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinilkin, I. G.; Chernov, V. I.; Medvedeva, A. A.

The purpose of the study was to evaluate the feasibility of using {sup 99m}Tc-Al{sub 2}O{sub 3}-based radiopharmaceutical, a novel molecular imaging agent for sentinel lymph node detection in patients with invasive cervical cancer. The study included 23 cervical cancer patients (T1aNxMx-T2bNxMx) treated at the Tomsk Cancer Research Institute. In the 18 hours before surgery, 80 MBq of the {sup 99m}Tc-Al{sub 2}O{sub 3} in peritumoral injected, followed by single-photon emission computed tomography (SPECT) of the pelvis and intraoperative SLN identification. Twenty-seven SLNs were detected by SPECT, and 34 SLNs were identified by intraoperative gamma probe. The total number of identified SLNsmore » per patient ranged from 1 to 3 (the mean number of SLNs was 1.4 per patient). The most common site for SLN detection was the external iliac region (57.2%), followed by the internal iliac (14%), obturator (14%), presacral and retrosacral regions (14%), and the parametrial region (1%). Sensitivity in detecting SLNs was 100% for intraoperative SLN identification and 79% for SPECT image.« less

Influence of the Pixel Sizes of Reference Computed Tomography on Single-photon Emission Computed Tomography Image Reconstruction Using Conjugate-gradient Algorithm.

PubMed

Okuda, Kyohei; Sakimoto, Shota; Fujii, Susumu; Ida, Tomonobu; Moriyama, Shigeru

The frame-of-reference using computed-tomography (CT) coordinate system on single-photon emission computed tomography (SPECT) reconstruction is one of the advanced characteristics of the xSPECT reconstruction system. The aim of this study was to reveal the influence of the high-resolution frame-of-reference on the xSPECT reconstruction. 99m Tc line-source phantom and National Electrical Manufacturers Association (NEMA) image quality phantom were scanned using the SPECT/CT system. xSPECT reconstructions were performed with the reference CT images in different sizes of the display field-of-view (DFOV) and pixel. The pixel sizes of the reconstructed xSPECT images were close to 2.4 mm, which is acquired as originally projection data, even if the reference CT resolution was varied. The full width at half maximum (FWHM) of the line-source, absolute recovery coefficient, and background variability of image quality phantom were independent on the sizes of DFOV in the reference CT images. The results of this study revealed that the image quality of the reconstructed xSPECT images is not influenced by the resolution of frame-of-reference on SPECT reconstruction.

Correction of nonuniform attenuation and image fusion in SPECT imaging by means of separate X-ray CT.

PubMed

Kashiwagi, Toru; Yutani, Kenji; Fukuchi, Minoru; Naruse, Hitoshi; Iwasaki, Tadaaki; Yokozuka, Koichi; Inoue, Shinichi; Kondo, Shoji

2002-06-01

Improvements in image quality and quantitation measurement, and the addition of detailed anatomical structures are important topics for single-photon emission tomography (SPECT). The goal of this study was to develop a practical system enabling both nonuniform attenuation correction and image fusion of SPECT images by means of high-performance X-ray computed tomography (CT). A SPECT system and a helical X-ray CT system were placed next to each other and linked with Ethernet. To avoid positional differences between the SPECT and X-ray CT studies, identical flat patient tables were used for both scans; body distortion was minimized with laser beams from the upper and lateral directions to detect the position of the skin surface. For the raw projection data of SPECT, a scatter correction was performed with the triple energy window method. Image fusion of the X-ray CT and SPECT images was performed automatically by auto-registration of fiducial markers attached to the skin surface. After registration of the X-ray CT and SPECT images, an X-ray CT-derived attenuation map was created with the calibration curve for 99mTc. The SPECT images were then reconstructed with scatter and attenuation correction by means of a maximum likelihood expectation maximization algorithm. This system was evaluated in torso and cylindlical phantoms and in 4 patients referred for myocardial SPECT imaging with Tc-99m tetrofosmin. In the torso phantom study, the SPECT and X-ray CT images overlapped exactly on the computer display. After scatter and attenuation correction, the artifactual activity reduction in the inferior wall of the myocardium improved. Conversely, the incresed activity around the torso surface and the lungs was reduced. In the abdomen, the liver activity, which was originally uniform, had recovered after scatter and attenuation correction processing. The clinical study also showed good overlapping of cardiac and skin surface outlines on the fused SPECT and X-ray CT images. The effectiveness of the scatter and attenuation correction process was similar to that observed in the phantom study. Because the total time required for computer processing was less than 10 minutes, this method of attenuation correction and image fusion for SPECT images is expected to become popular in clinical practice.

Detection of Sentinel Lymph Nodes in Gynecologic Tumours by Planar Scintigraphy and SPECT/CT

PubMed Central

Kraft, Otakar; Havel, Martin

2012-01-01

Objective: Assess the role of planar lymphoscintigraphy and fusion imaging of SPECT/CT in sentinel lymph node (SLN) detection in patients with gynecologic tumours. Material and Methods: Planar scintigraphy and hybrid modality SPECT/CT were performed in 64 consecutive women with gynecologic tumours (mean age 53.6 with range 30-77 years): 36 pts with cervical cancer (Group A), 21 pts with endometrial cancer (Group B), 7 pts with vulvar carcinoma (Group C). Planar and SPECT/CT images were interpreted separately by two nuclear medicine physicians. Efficacy of these two techniques to image SLN were compared. Results: Planar scintigraphy did not image SLN in 7 patients (10.9%), SPECT/CT was negative in 4 patients (6.3%). In 35 (54.7%) patients the number of SLNs captured on SPECT/CT was higher than on planar imaging. Differences in detection of SLN between planar and SPECT/CT imaging in the group of all 64 patients are statistically significant (p<0.05). Three foci of uptake (1.7% from totally visible 177 foci on planar images) in 2 patients interpreted on planar images as hot LNs were found to be false positive non-nodal sites of uptake when further assessed on SPECT/CT. SPECT/CT showed the exact anatomical location of all visualised sentinel nodes. Conclusion: In some patients with gynecologic cancers SPECT/CT improves detection of sentinel lymph nodes. It can image nodes not visible on planar scintigrams, exclude false positive uptake and exactly localise pelvic and paraaortal SLNs. It improves anatomic localization of SLNs. Conflict of interest:None declared. PMID:23486989

Molecular imaging of angiogenesis with SPECT

PubMed Central

Boerman, Otto C.

2010-01-01

Single-photon emission computed tomography (SPECT) and position emission tomography (PET) are the two main imaging modalities in nuclear medicine. SPECT imaging is more widely available than PET imaging and the radionuclides used for SPECT are easier to prepare and usually have a longer half-life than those used for PET. In addition, SPECT is a less expensive technique than PET. Commonly used gamma emitters are: 99mTc (Emax 141 keV, T1/2 6.02 h), 123I (Emax 529 keV, T1/2 13.0 h) and 111In (Emax 245 keV, T1/2 67.2 h). Compared to clinical SPECT, PET has a higher spatial resolution and the possibility to more accurately estimate the in vivo concentration of a tracer. In preclinical imaging, the situation is quite different. The resolution of microSPECT cameras (<0.5 mm) is higher than that of microPET cameras (>1.5 mm). In this report, studies on new radiolabelled tracers for SPECT imaging of angiogenesis in tumours are reviewed. PMID:20617435

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siman, W.; Mikell, J. K.; Kappadath, S. C., E-mail

Purpose: To develop a practical background compensation (BC) technique to improve quantitative {sup 90}Y-bremsstrahlung single-photon emission computed tomography (SPECT)/computed tomography (CT) using a commercially available imaging system. Methods: All images were acquired using medium-energy collimation in six energy windows (EWs), ranging from 70 to 410 keV. The EWs were determined based on the signal-to-background ratio in planar images of an acrylic phantom of different thicknesses (2–16 cm) positioned below a {sup 90}Y source and set at different distances (15–35 cm) from a gamma camera. The authors adapted the widely used EW-based scatter-correction technique by modeling the BC as scaled images.more » The BC EW was determined empirically in SPECT/CT studies using an IEC phantom based on the sphere activity recovery and residual activity in the cold lung insert. The scaling factor was calculated from 20 clinical planar {sup 90}Y images. Reconstruction parameters were optimized in the same SPECT images for improved image quantification and contrast. A count-to-activity calibration factor was calculated from 30 clinical {sup 90}Y images. Results: The authors found that the most appropriate imaging EW range was 90–125 keV. BC was modeled as 0.53× images in the EW of 310–410 keV. The background-compensated clinical images had higher image contrast than uncompensated images. The maximum deviation of their SPECT calibration in clinical studies was lowest (<10%) for SPECT with attenuation correction (AC) and SPECT with AC + BC. Using the proposed SPECT-with-AC + BC reconstruction protocol, the authors found that the recovery coefficient of a 37-mm sphere (in a 10-mm volume of interest) increased from 39% to 90% and that the residual activity in the lung insert decreased from 44% to 14% over that of SPECT images with AC alone. Conclusions: The proposed EW-based BC model was developed for {sup 90}Y bremsstrahlung imaging. SPECT with AC + BC gave improved lesion detectability and activity quantification compared to SPECT with AC only. The proposed methodology can readily be used to tailor {sup 90}Y SPECT/CT acquisition and reconstruction protocols with different SPECT/CT systems for quantification and improved image quality in clinical settings.« less

Comparison of TOF-PET and Bremsstrahlung SPECT Images of Yttrium-90: A Monte Carlo Simulation Study.

PubMed

Takahashi, Akihiko; Himuro, Kazuhiko; Baba, Shingo; Yamashita, Yasuo; Sasaki, Masayuki

2018-01-01

Yttrium-90 ( 90 Y) is a beta particle nuclide used in targeted radionuclide therapy which is available to both single-photon emission computed tomography (SPECT) and time-of-flight (TOF) positron emission tomography (PET) imaging. The purpose of this study was to assess the image quality of PET and Bremsstrahlung SPECT by simulating PET and SPECT images of 90 Y using Monte Carlo simulation codes under the same conditions and to compare them. In-house Monte Carlo codes, MCEP-PET and MCEP-SPECT, were employed to simulate images. The phantom was a torso-shaped phantom containing six hot spheres of various sizes. The background concentrations of 90 Y were set to 50, 100, 150, and 200 kBq/mL, and the concentrations of the hot spheres were 10, 20, and 40 times of those of the background concentrations. The acquisition time was set to 30 min, and the simulated sinogram data were reconstructed using the ordered subset expectation maximization method. The contrast recovery coefficient (CRC) and contrast-to-noise ratio (CNR) were employed to evaluate the image qualities. The CRC values of SPECT images were less than 40%, while those of PET images were more than 40% when the hot sphere was larger than 20 mm in diameter. The CNR values of PET images of hot spheres of diameter smaller than 20 mm were larger than those of SPECT images. The CNR values mostly exceeded 4, which is a criterion to evaluate the discernibility of hot areas. In the case of SPECT, hot spheres of diameter smaller than 20 mm were not discernable. On the contrary, the CNR values of PET images decreased to the level of SPECT, in the case of low concentration. In almost all the cases examined in this investigation, the quantitative indexes of TOF-PET 90 Y images were better than those of Bremsstrahlung SPECT images. However, the superiority of PET image became critical in the case of low activity concentrations.

A comparison of rat SPECT images obtained using (99m)Tc derived from 99Mo produced by an electron accelerator with that from a reactor.

PubMed

Galea, R; Wells, R G; Ross, C K; Lockwood, J; Moore, K; Harvey, J T; Isensee, G H

2013-05-07

Recent shortages of molybdenum-99 ((99)Mo) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce (99)Mo from which technetium-99m ((99m)Tc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced (99m)Tc with those obtained using (99m)Tc from a commercial generator were compared. Disks of (100)Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of (99)Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the (99m)Tc, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using (99m)Tc from a standard reactor (99)Mo generator. The efficiency of (99)Mo-(99m)Tc separation was typically greater than 90%. This study demonstrated the delivery of (99m)Tc from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced (99m)Tc were comparable. High-power electron accelerators are an attractive option for producing (99)Mo on a national scale.

Automatic and remote controlled ictal SPECT injection for seizure focus localization by use of a commercial contrast agent application pump.

PubMed

Feichtinger, Michael; Eder, Hans; Holl, Alexander; Körner, Eva; Zmugg, Gerda; Aigner, Reingard; Fazekas, Franz; Ott, Erwin

2007-07-01

In the presurgical evaluation of patients with partial epilepsy, the ictal single photon emission computed tomography (SPECT) is a useful noninvasive diagnostic tool for seizure focus localization. To achieve optimal SPECT scan quality, ictal tracer injection should be carried out as quickly as possible after the seizure onset and under highest safety conditions possible. Compared to the commonly used manual injection, an automatic administration of the radioactive tracer may provide higher quality standards for this procedure. In this study, therefore, we retrospectively analyzed efficiency and safety of an automatic injection system for ictal SPECT tracer application. Over a 31-month period, 26 patients underwent ictal SPECT by use of an automatic remote-controlled injection pump originally designed for CT-contrast agent application. Various factors were reviewed, including latency of ictal injection, radiation safety parameters, and ictal seizure onset localizing value. Times between seizure onset and tracer injection ranged between 3 and 48 s. In 21 of 26 patients ictal SPECT supported the localization of the epileptogenic focus in the course of the presurgical evaluation. In all cases ictal SPECT tracer injection was performed with a high degree of safety to patients and staff. Ictal SPECT by use of a remote-controlled CT-contrast agent injection system provides a high scan quality and is a safe and confirmatory presurgical evaluation technique in the epilepsy-monitoring unit.

The significance of 99mTc-MAA SPECT/CT liver perfusion imaging in treatment planning for 90Y-microsphere selective internal radiation treatment.

PubMed

Ahmadzadehfar, Hojjat; Sabet, Amir; Biermann, Kim; Muckle, Marianne; Brockmann, Holger; Kuhl, Christiane; Wilhelm, Kai; Biersack, Hans-Jürgen; Ezziddin, Samer

2010-08-01

Selective internal radiation therapy (SIRT), a catheter-based liver-directed modality for treating primary and metastatic liver cancer, requires appropriate planning to maximize its therapeutic response and minimize its side effects. (99m)Tc-macroaggregated albumin (MAA) scanning should precede the therapy to detect any extrahepatic shunting to the lung or gastrointestinal tract. Our aim was to compare the ability of SPECT/CT with that of planar imaging and SPECT in the detection and localization of extrahepatic (99m)Tc-MAA accumulation and to evaluate the impact of SPECT/CT on SIRT treatment planning and its added value to angiography in this setting. Ninety diagnostic hepatic angiograms with (99m)Tc-MAA were obtained for 76 patients with different types of cancer. All images were reviewed retrospectively for extrahepatic MAA deposition in the following order: planar, non-attenuation-corrected SPECT, and SPECT/CT. Review of angiograms and follow-up of patients with abdominal shunting served as reference standards. Extrahepatic accumulation was detected by planar imaging, SPECT, and SPECT/CT in 12%, 17%, and 42% of examinations, respectively. The sensitivity for detecting extrahepatic shunting with planar imaging, SPECT, and SPECT/CT was 32%, 41%, and 100%, respectively; specificity was 98%, 98%, and 93%, respectively. The respective positive predictive values were 92%, 93%, and 89%, and the respective negative predictive values were 71%, 73%, and 100%. The therapy plan was changed according to the results of planar imaging, SPECT, and SPECT/CT in 7.8%, 8.9%, and 29% of patients, respectively. In pre-SIRT planning, (99m)Tc-MAA SPECT/CT is valuable for identifying extrahepatic visceral sites at risk for postradioembolization complications.

Nuclear myocardial perfusion imaging using thallium-201 with a novel multifocal collimator SPECT/CT: IQ-SPECT versus conventional protocols in normal subjects.

PubMed

Matsuo, Shinro; Nakajima, Kenichi; Onoguchi, Masahisa; Wakabayash, Hiroshi; Okuda, Koichi; Kinuya, Seigo

2015-06-01

A novel multifocal collimator, IQ-SPECT (Siemens) consists of SMARTZOOM, cardio-centric and 3D iterative SPECT reconstruction and makes it possible to perform MPI scans in a short time. The aims are to delineate the normal uptake in thallium-201 ((201)Tl) SPECT in each acquisition method and to compare the distribution between new and conventional protocol, especially in patients with normal imaging. Forty patients (eight women, mean age of 75 years) who underwent myocardial perfusion imaging were included in the study. All patients underwent one-day protocol perfusion scan after an adenosine-stress test and at rest after administering (201)Tl and showed normal results. Acquisition was performed on a Symbia T6 equipped with a conventional dual-headed gamma camera system (Siemens ECAM) and with a multifocal SMARTZOOM collimator. Imaging was performed with a conventional system followed by IQ-SPECT/computed tomography (CT). Reconstruction was performed with or without X-ray CT-derived attenuation correction (AC). Two nuclear physicians blinded to clinical information interpreted all myocardial perfusion images. A semi-quantitative myocardial perfusion was analyzed by a 17-segment model with a 5-point visual scoring. The uptake of each segment was measured and left ventricular functions were analyzed by QPS software. IQ-SPECT provided good or excellent image quality. The quality of IQ-SPECT images without AC was similar to those of conventional LEHR study. Mid-inferior defect score (0.3 ± 0.5) in the conventional LEHR study was increased significantly in IQ-SPECT with AC (0 ± 0). IQ-SPECT with AC improved the mid-inferior decreased perfusion shown in conventional images. The apical tracer count in IQ-SPECT with AC was decreased compared to that in LEHR (0.1 ± 0.3 vs. 0.5 ± 0.7, p < 0.05). The left ventricular ejection fraction from IQ-SPECT was significantly higher than that from the LEHR collimator (p = 0.0009). The images of IQ-SPECT acquired in a short time are equivalent to that of conventional LEHR. The results indicated that the IQ-SPECT system with AC is capable of correcting inferior artifacts with high image quality.

Gated-SPECT myocardial perfusion imaging as a complementary technique to magnetic resonance imaging in chronic myocardial infarction patients.

PubMed

Cuberas-Borrós, Gemma; Pineda, Victor; Aguadé-Bruix, Santiago; Romero-Farina, Guillermo; Pizzi, M Nazarena; de León, Gustavo; Castell-Conesa, Joan; García-Dorado, David; Candell-Riera, Jaume

2013-09-01

The aim of this study was to compare magnetic resonance and gated-SPECT myocardial perfusion imaging in patients with chronic myocardial infarction. Magnetic resonance imaging and gated-SPECT were performed in 104 patients (mean age, 61 [12] years; 87.5% male) with a previous infarction. Left ventricular volumes and ejection fraction and classic late gadolinium enhancement viability criteria (<75% transmurality) were correlated with those of gated-SPECT (uptake >50%) in the 17 segments of the left ventricle. Motion, thickening, and ischemia on SPECT were analyzed in segments showing nonviable tissue or equivocal enhancement features (50%-75% transmurality). A good correlation was observed between the 2 techniques for volumes, ejection fraction (P<.05), and estimated necrotic mass (P<.01). In total, 82 of 264 segments (31%) with >75% enhancement had >50% single SPECT uptake. Of the 106 equivocal segments on magnetic resonance imaging, 68 (64%) had >50% uptake, 41 (38.7%) had normal motion, 46 (43.4%) had normal thickening, and 17 (16%) had ischemic criteria on SPECT. A third of nonviable segments on magnetic resonance imaging showed >50% uptake on SPECT. Gated-SPECT can be useful in the analysis of motion, thickening, and ischemic criteria in segments with questionable viability on magnetic resonance imaging. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition.

PubMed

Desbois, Nicolas; Pacquelet, Sandrine; Dubois, Adrien; Michelin, Clément; Gros, Claude P

2015-01-01

The Cu(I)-catalysed Huisgen cycloaddition, known as "click" reaction, has been applied to the synthesis of a range of triazole-linked porphyrin/corrole to DOTA/NOTA derivatives. Microwave irradiation significantly accelerates the reaction. The synthesis of heterobimetallic complexes was easily achieved in up to 60% isolated yield. Heterobimetallic complexes were easily prepared as potential MRI/PET (SPECT) bimodal contrast agents incorporating one metal (Mn, Gd) for the enhancement of contrast for MRI applications and one "cold" metal (Cu, Ga, In) for future radionuclear imaging applications. Preliminary relaxivity measurements showed that the reported complexes are promising contrast agents (CA) in MRI.

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition

PubMed Central

Desbois, Nicolas; Pacquelet, Sandrine; Dubois, Adrien; Michelin, Clément

2015-01-01

Summary The Cu(I)-catalysed Huisgen cycloaddition, known as “click” reaction, has been applied to the synthesis of a range of triazole-linked porphyrin/corrole to DOTA/NOTA derivatives. Microwave irradiation significantly accelerates the reaction. The synthesis of heterobimetallic complexes was easily achieved in up to 60% isolated yield. Heterobimetallic complexes were easily prepared as potential MRI/PET (SPECT) bimodal contrast agents incorporating one metal (Mn, Gd) for the enhancement of contrast for MRI applications and one “cold” metal (Cu, Ga, In) for future radionuclear imaging applications. Preliminary relaxivity measurements showed that the reported complexes are promising contrast agents (CA) in MRI. PMID:26664643

SPECT/CT in patients with lower back pain after lumbar fusion surgery.

PubMed

Sumer, Johannes; Schmidt, Daniela; Ritt, Philipp; Lell, Michael; Forst, Raimund; Kuwert, Torsten; Richter, Richard

2013-10-01

The aim of the study was to investigate the incremental diagnostic value of skeletal hybrid imaging with single-photon emission computed tomography and X-ray computed tomography (SPECT/CT) over conventional nuclear medical imaging in patients with lower back pain after lumbar fusion surgery (LFS). This retrospective study comprised 37 patients suffering from lower back pain after LFS in whom three-phase planar bone scintigraphies of the lumbar spine including SPECT/CT of that region had been performed. The findings visible on these imaging data sets were classified into the following five diagnostic categories: (a) metal loosening; (b) insufficient stabilizing function of the metal implants indicated by metabolically active facet joint arthritis and/or intervertebral osteochondrosis in the instrumented region; (c) adjacent instability defined as metabolically active degenerative disease in the segments adjacent to the instrumented region; (d) indeterminate; and (e) normal. In the case of eight patients no lesions were visible on their planar scintigraphy and SPECT (planar/SPECT) or SPECT/CT images. In the remaining 29 patients, planar/SPECT disclosed 62 pathological foci of uptake within the graft region and SPECT/CT revealed 55. The rate of reclassification by SPECT/CT compared with planar/SPECT was 5/12 for lesions categorized as metal loosening by planar/SPECT, 16/29 for foci with a planar/SPECT diagnosis of insufficient stabilizing function, 7/20 when the planar/SPECT diagnosis had been adjacent instability, and 1/1 for the lesions indeterminate on planar/SPECT. Two lesions had been detected on SPECT/CT only. The overall rate of reclassification was 45.2% (28/62) (95% confidence interval, 33.4-57.5%). Because of its significantly higher accuracy compared with planar/SPECT, SPECT/CT should be the conventional nuclear medical procedure of choice for patients with lower back pain after LFS.

A guide to SPECT equipment for brain imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffer, P.B.; Zubal, G.

1991-12-31

Single photon emission computed tomography (SPECT) was started by Kuhl and Edwards about 30 years ago. Their original instrument consisted of four focused Nal probes mounted on a moving gantry. During the 1980s, clinical SPECT imaging was most frequently performed using single-headed Anger-type cameras which were modified for rotational as well as static imaging. Such instruments are still available and may be useful in settings where there are few patients and SPECT is used only occasionally. More frequently, however, dedicated SPECT devices are purchased which optimize equipment potential while being user-friendly. Modern SPECT instrumentation incorporates improvements in the detector, computers,more » mathematical formulations, electronics and display systems. A comprehensive discussion of all aspects of SPECT is beyond the scope of this article. The authors, however, discuss general concepts of SPECT, the current state-of-the-art in clinical SPECT instrumentation, and areas of common misunderstanding. 9 refs.« less

Apparent CBF decrease with normal aging due to partial volume effects: MR-based partial volume correction on CBF SPECT.

PubMed

Inoue, Kentaro; Ito, Hiroshi; Goto, Ryoi; Nakagawa, Manabu; Kinomura, Shigeo; Sato, Tachio; Sato, Kazunori; Fukuda, Hiroshi

2005-06-01

Several studies using single photon emission tomography (SPECT) have shown changes in cerebral blood flow (CBF) with age, which were associated with partial volume effects by some authors. Some studies have also demonstrated gender-related differences in CBF. The present study aimed to examine age and gender effects on CBF SPECT images obtained using the 99mTc-ethyl cysteinate dimer and a SPECT scanner, before and after partial volume correction (PVC) using magnetic resonance (MR) imaging. Forty-four healthy subjects (29 males and 15 females; age range, 27-64 y; mean age, 50.0 +/- 9.8 y) participated. Each MR image was segmented to yield grey and white matter images and coregistered to a corresponding SPECT image, followed by convolution to approximate the SPECT spatial resolution. PVC-SPECT images were produced using the convoluted grey matter MR (GM-MR) and white matter MR images. The age and gender effects were assessed using SPM99. Decreases with age were detected in the anterolateral prefrontal cortex and in areas along the lateral sulcus and the lateral ventricle, bilaterally, in the GM-MR images and the SPECT images. In the PVC-SPECT images, decreases in CBF in the lateral prefrontal cortex lost their statistical significance. Decreases in CBF with age found along the lateral sulcus and the lateral ventricle, on the other hand, remained statistically significant, but observation of the spatially normalized MR images suggests that these findings are associated with the dilatation of the lateral sulcus and lateral ventricle, which was not completely compensated for by the spatial normalization procedure. Our present study demonstrated that age effects on CBF in healthy subjects could reflect morphological differences with age in grey matter.

MO-G-17A-02: Computer Simulation Studies for On-Board Functional and Molecular Imaging of the Prostate Using a Robotic Multi-Pinhole SPECT System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, L; Duke University Medical Center, Durham, NC; Fudan University Shanghai Cancer Center, Shanghai

Purpose: To investigate prostate imaging onboard radiation therapy machines using a novel robotic, 49-pinhole Single Photon Emission Computed Tomography (SPECT) system. Methods: Computer-simulation studies were performed for region-of-interest (ROI) imaging using a 49-pinhole SPECT collimator and for broad cross-section imaging using a parallel-hole SPECT collimator. A male XCAT phantom was computersimulated in supine position with one 12mm-diameter tumor added in the prostate. A treatment couch was added to the phantom. Four-minute detector trajectories for imaging a 7cm-diameter-sphere ROI encompassing the tumor were investigated with different parameters, including pinhole focal length, pinhole diameter and trajectory starting angle. Pseudo-random Poisson noise wasmore » included in the simulated projection data, and SPECT images were reconstructed by OSEM with 4 subsets and up to 10 iterations. Images were evaluated by visual inspection, profiles, and Root-Mean- Square-Error (RMSE). Results: The tumor was well visualized above background by the 49-pinhole SPECT system with different pinhole parameters while it was not visible with parallel-hole SPECT imaging. Minimum RMSEs were 0.30 for 49-pinhole imaging and 0.41 for parallelhole imaging. For parallel-hole imaging, the detector trajectory from rightto- left yielded slightly lower RMSEs than that from posterior to anterior. For 49-pinhole imaging, near-minimum RMSEs were maintained over a broader range of OSEM iterations with a 5mm pinhole diameter and 21cm focal length versus a 2mm diameter pinhole and 18cm focal length. The detector with 21cm pinhole focal length had the shortest rotation radius averaged over the trajectory. Conclusion: On-board functional and molecular prostate imaging may be feasible in 4-minute scan times by robotic SPECT. A 49-pinhole SPECT system could improve such imaging as compared to broadcross-section parallel-hole collimated SPECT imaging. Multi-pinhole imaging can be improved by considering pinhole focal length, pinhole diameter, and trajectory starting angle. The project is supported by the NIH grant 5R21-CA156390.« less

Use of molecular targeted agents for the diagnosis, staging and therapy of neuroendocrine malignancy

PubMed Central

2010-01-01

Abstract Imaging of neuroendocrine tumours (NET) poses significant challenges because of the heterogeneous biology of the tumours that are represented by this class of neoplasia. NET can range from benign lesions to highly aggressive cancers. Structural imaging techniques have suboptimal sensitivity in most published series and diagnosis is often delayed until metastatic disease is present. Current guidelines emphasise the importance of functional imaging for evaluating the extent of NET. The mainstay of this type of imaging has been somatostatin receptor scintigraphy (SRS) with [111In]diethylenetriaminepentaacetic acid-octreotide (Octreoscan™). Routine use of single-photon emission computed tomography (SPECT) and particularly of hybrid SPECT/computed tomography (CT) has significantly improved localisation of tumour sites and evaluation of somatostatin receptor (SSTR) expression, which is important for predicting the likelihood of response to somatostatin analogues (SSA). Positron emission tomography (PET) can also now be used for evaluating SSTR expression. There are a number of peptides that have been evaluated but [68Ga]tetraazocyclodecanetetraacetic acid (DOTA)-octreotate (GaTate) PET/CT, which has been shown to be significantly more sensitive for detecting small lesions than Octreoscan™, is now probably the preferred agent because high uptake in known sites of disease provides a diagnostic pair for assessing suitability of patients for [177Lu]DOTA-octreotate (LuTate) peptide receptor radionuclide therapy (PRRT). A range of other radiolabelled SSA has also been used for PRRT. Lesions without SSTR expression require alternative imaging and therapeutic strategies. Although fluorodeoxyglucose (FDG) uptake in low-grade NET is not generally increased relative to normal tissues, the loss of differentiation that often accompanies loss of SSTR expression may be associated with a significant increase in glycolytic metabolism and an accompanying improvement in the diagnostic sensitivity of FDG PET/CT. High FDG avidity is associated with a poorer prognosis but increases the likelihood of response to chemotherapy. Functioning tumours also require substrates for their secreted products. This can be exploited for NET imaging with amine precursor uptake being imaged using [18F]3,4-dihydrophenylalanine and serotonin-secreting tumours being sensitively detected using [11C]5-hydroxytryptamine. Both these agents are suitable for imaging with PET. [123I]meta-Iodo-benzyl-guanidine (MIBG) SPECT/CT may also be useful as a staging technique, particularly for NET of the sympathetic neuronal chain, and can identify patients who may be suitable for [131I]MIBG therapy. In the future, paradigms guided by clinical and biopsy features should allow personalised imaging paradigms aligned to therapeutic options. PMID:20880795

A combined static-dynamic single-dose imaging protocol to compare quantitative dynamic SPECT with static conventional SPECT.

PubMed

Sciammarella, Maria; Shrestha, Uttam M; Seo, Youngho; Gullberg, Grant T; Botvinick, Elias H

2017-08-03

SPECT myocardial perfusion imaging (MPI) is a clinical mainstay that is typically performed with static imaging protocols and visually or semi-quantitatively assessed for perfusion defects based upon the relative intensity of myocardial regions. Dynamic cardiac SPECT presents a new imaging technique based on time-varying information of radiotracer distribution, which permits the evaluation of regional myocardial blood flow (MBF) and coronary flow reserve (CFR). In this work, a preliminary feasibility study was conducted in a small patient sample designed to implement a unique combined static-dynamic single-dose one-day visit imaging protocol to compare quantitative dynamic SPECT with static conventional SPECT for improving the diagnosis of coronary artery disease (CAD). Fifteen patients (11 males, four females, mean age 71 ± 9 years) were enrolled for a combined dynamic and static SPECT (Infinia Hawkeye 4, GE Healthcare) imaging protocol with a single dose of 99m Tc-tetrofosmin administered at rest and a single dose administered at stress in a one-day visit. Out of 15 patients, eleven had selective coronary angiography (SCA), 8 within 6 months and the rest within 24 months of SPECT imaging, without intervening symptoms or interventions. The extent and severity of perfusion defects in each myocardial region was graded visually. Dynamically acquired data were also used to estimate the MBF and CFR. Both visually graded images and estimated CFR were tested against SCA as a reference to evaluate the validity of the methods. Overall, conventional static SPECT was normal in ten patients and abnormal in five patients, dynamic SPECT was normal in 12 patients and abnormal in three patients, and CFR from dynamic SPECT was normal in nine patients and abnormal in six patients. Among those 11 patients with SCA, conventional SPECT was normal in 5, 3 with documented CAD on SCA with an overall accuracy of 64%, sensitivity of 40% and specificity of 83%. Dynamic SPECT image analysis also produced a similar accuracy, sensitivity, and specificity. CFR was normal in 6, each with CAD on SCA with an overall accuracy of 91%, sensitivity of 80%, and specificity of 100%. The mean CFR was significantly lower for SCA detected abnormal than for normal patients (3.86±1.06 vs 1.94±0. 0.67, P < 0.001). The visually assessed image findings in static and dynamic SPECT are subjective, and may not reflect direct physiologic measures of coronary lesion based on SCA. The CFR measured with dynamic SPECT is fully objective, with better sensitivity and specificity, available only with the data generated from the dynamic SPECT method.

Design and performance of a multi-pinhole collimation device for small animal imaging with clinical SPECT and SPECT-CT scanners

PubMed Central

DiFilippo, Frank P.

2008-01-01

A multi-pinhole collimation device is developed that uses the gamma camera detectors of a clinical SPECT or SPECT-CT scanner to produce high resolution SPECT images. The device consists of a rotating cylindrical collimator having 22 tungsten pinholes with 0.9 mm diameter apertures and an animal bed inside the collimator that moves linearly to provide helical or ordered-subsets axial sampling. CT images also may be acquired on a SPECT-CT scanner for purposes of image co-registration and SPECT attenuation correction. The device is placed on the patient table of the scanner without attaching to the detectors or scanner gantry. The system geometry is calibrated in-place from point source data and is then used during image reconstruction. The SPECT imaging performance of the device is evaluated with test phantom scans. Spatial resolution from reconstructed point source images is measured to be 0.6 mm full width at half maximum or better. Micro-Derenzo phantom images demonstrate the ability to resolve 0.7 mm diameter rod patterns. The axial slabs of a Micro-Defrise phantom are visualized well. Collimator efficiency exceeds 0.05% at the center of the field of view, and images of a uniform phantom show acceptable uniformity and minimal artifact. The overall simplicity and relatively good imaging performance of the device make it an interesting low-cost alternative to dedicated small animal scanners. PMID:18635899

Design and performance of a multi-pinhole collimation device for small animal imaging with clinical SPECT and SPECT CT scanners

NASA Astrophysics Data System (ADS)

Di Filippo, Frank P.

2008-08-01

A multi-pinhole collimation device is developed that uses the gamma camera detectors of a clinical SPECT or SPECT-CT scanner to produce high-resolution SPECT images. The device consists of a rotating cylindrical collimator having 22 tungsten pinholes with 0.9 mm diameter apertures and an animal bed inside the collimator that moves linearly to provide helical or ordered-subsets axial sampling. CT images also may be acquired on a SPECT-CT scanner for purposes of image co-registration and SPECT attenuation correction. The device is placed on the patient table of the scanner without attaching to the detectors or scanner gantry. The system geometry is calibrated in-place from point source data and is then used during image reconstruction. The SPECT imaging performance of the device is evaluated with test phantom scans. Spatial resolution from reconstructed point source images is measured to be 0.6 mm full width at half maximum or better. Micro-Derenzo phantom images demonstrate the ability to resolve 0.7 mm diameter rod patterns. The axial slabs of a Micro-Defrise phantom are visualized well. Collimator efficiency exceeds 0.05% at the center of the field of view, and images of a uniform phantom show acceptable uniformity and minimal artifact. The overall simplicity and relatively good imaging performance of the device make it an interesting low-cost alternative to dedicated small animal scanners.

Development of an inflammation imaging tracer, 111In-DOTA-DAPTA, targeting chemokine receptor CCR5 and preliminary evaluation in an ApoE-/- atherosclerosis mouse model.

PubMed

Wei, Lihui; Petryk, Julia; Gaudet, Chantal; Kamkar, Maryam; Gan, Wei; Duan, Yin; Ruddy, Terrence D

2018-02-07

Chemokine receptor 5 (CCR5) plays an important role in atherosclerosis. Our objective was to develop a SPECT tracer targeting CCR5 for imaging plaque inflammation by radiolabeling D-Ala-peptide T-amide (DAPTA), a CCR5 antagonist, with 111 In. 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) conjugated DAPTA (DOTA-DAPTA) was labeled with 111 In. Cell uptake studies were conducted in U87-CD4-CCR5 and U87-MG cells. Biodistribution was determined in C57BL/6 mice. Autoradiography, en face and Oil Red O (ORO) imaging studies were performed in ApoE -/- mice. DOTA-DAPTA was radiolabeled with 111 In with high radiochemical purity (> 98%) and specific activity (70 MBq·nmol). 111 In-DOTA-DAPTA exhibited fast blood and renal clearance and high spleen uptake. The U87-CD4-CCR5 cells had significantly higher uptake in comparison to the U87-MG cells. The cell uptake was reduced by three times with DAPTA, indicating the receptor specificity of the uptake. Autoradiographic images showed significantly higher lesion uptake of 111 In-DOTA-DAPTA in ApoE -/- mice than that in C57BL/6 mice. The tracer uptake in 4 month old ApoE -/- high fat diet (HFD) mice with blocking agent was twofold lower than the same mice without the blocking agent, demonstrating the specificity of the tracer for the CCR5 receptor. 111 In-DOTA-DAPTA, specifically targeting chemokine receptor CCR5, is a potential SPECT agent for imaging inflammation in atherosclerosis.

Molecular Imaging of Pancreatic Cancer with Antibodies

PubMed Central

2015-01-01

Development of novel imaging probes for cancer diagnostics remains critical for early detection of disease, yet most imaging agents are hindered by suboptimal tumor accumulation. To overcome these limitations, researchers have adapted antibodies for imaging purposes. As cancerous malignancies express atypical patterns of cell surface proteins in comparison to noncancerous tissues, novel antibody-based imaging agents can be constructed to target individual cancer cells or surrounding vasculature. Using molecular imaging techniques, these agents may be utilized for detection of malignancies and monitoring of therapeutic response. Currently, there are several imaging modalities commonly employed for molecular imaging. These imaging modalities include positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance (MR) imaging, optical imaging (fluorescence and bioluminescence), and photoacoustic (PA) imaging. While antibody-based imaging agents may be employed for a broad range of diseases, this review focuses on the molecular imaging of pancreatic cancer, as there are limited resources for imaging and treatment of pancreatic malignancies. Additionally, pancreatic cancer remains the most lethal cancer with an overall 5-year survival rate of approximately 7%, despite significant advances in the imaging and treatment of many other cancers. In this review, we discuss recent advances in molecular imaging of pancreatic cancer using antibody-based imaging agents. This task is accomplished by summarizing the current progress in each type of molecular imaging modality described above. Also, several considerations for designing and synthesizing novel antibody-based imaging agents are discussed. Lastly, the future directions of antibody-based imaging agents are discussed, emphasizing the potential applications for personalized medicine. PMID:26620581

Implementation and assessment of an animal management system for small-animal micro-CT / micro-SPECT imaging

NASA Astrophysics Data System (ADS)

Holdsworth, David W.; Detombe, Sarah A.; Chiodo, Chris; Fricke, Stanley T.; Drangova, Maria

2011-03-01

Advances in laboratory imaging systems for CT, SPECT, MRI, and PET facilitate routine micro-imaging during pre-clinical investigations. Challenges still arise when dealing with immune-compromised animals, biohazardous agents, and multi-modality imaging. These challenges can be overcome with an appropriate animal management system (AMS), with the capability for supporting and monitoring a rat or mouse during micro-imaging. We report the implementation and assessment of a new AMS system for mice (PRA-3000 / AHS-2750, ASI Instruments, Warren MI), designed to be compatible with a commercial micro-CT / micro-SPECT imaging system (eXplore speCZT, GE Healthcare, London ON). The AMS was assessed under the following criteria: 1) compatibility with the imaging system (i.e. artifact generation, geometric dimensions); 2) compatibility with live animals (i.e. positioning, temperature regulation, anesthetic supply); 3) monitoring capabilities (i.e. rectal temperature, respiratory and cardiac monitoring); 4) stability of co-registration; and 5) containment. Micro-CT scans performed using a standardized live-animal protocol (90 kVp, 40 mA, 900 views, 16 ms per view) exhibited low noise (+/-19 HU) and acceptable artifact from high-density components within the AMS (e.g. ECG pad contacts). Live mice were imaged repeatedly (with removal and replacement of the AMS) and spatial registration was found to be stable to within +/-0.07 mm. All animals tolerated enclosure within the AMS for extended periods (i.e. > one hour) without distress, based on continuous recordings of rectal temperature, ECG waveform and respiratory rate. A sealed AMS system extends the capability of a conventional micro-imaging system to include immune-compromised and biosafety level 2 mouse-imaging protocols.

Investigation of SP94 Peptide as a Specific Probe for Hepatocellular Carcinoma Imaging and Therapy

PubMed Central

Li, Yanli; Hu, Yan; Xiao, Jie; Liu, Guobing; Li, Xiao; Zhao, Yanzhao; Tan, Hui; Shi, Hongcheng; Cheng, Dengfeng

2016-01-01

SP94 (SFSIIHTPILPL), a novel peptide, has shown specific binding to hepatocellular carcinoma (HCC) cells. We aimed to investigate the capability of SP94 as a targeting probe for HCC imaging and therapy following labeling with technetium-99m (99mTc) and rhenium-188 (188Re). HYNIC-SP94 was prepared by solid phase synthesis and then labeled with 99mTc. Cell competitive binding, internalization assay, in vitro and in vivo stability, biodistribution and micro-single photon emission computed tomography /computed tomography (SPECT/CT) imaging studies were performed to investigate the capability of 99mTc tricine-EDDA/HYNIC-SP94 as a specific HCC imaging probe. Initial promising targeting results inspired evaluation of its therapeutic effect when labeled by 188Re. HYNIC-SP94 was then labeled again with 188Re to perform cell apoptosis, microSPECT/CT imaging evaluation and immunohistochemistry. Huh-7 cells exhibited typical apoptotic changes after 188Re irradiation. According to 99mTc tricine-EDDA/HYNIC-SP94 microSPECT/CT imaging, tumor uptake was significantly decreased compared with that of pre-treatment with 188Re-HYNIC-SP94. The immunohistochemistry also displayed obvious necrosis and apoptosis as well as inhibition of proliferation in the 188Re-HYNIC-SP94 treatment group. The results supported that 99mTc tricine-EDDA/HYNIC-SP94 is able to target HCC cells and 188Re-HYNIC- SP94 holds potential as a therapeutic agent for HCC, making 99mTc/188Re-HYNIC-SP94 a promising targeting probe for HCC imaging and therapy. PMID:27649935

A Novel Multifunctional Theranostic Liposome Drug Delivery System: Construction, Characterization, and Multimodality MR, Near-infrared Fluorescent and Nuclear Imaging

PubMed Central

Li, Shihong; Goins, Beth; Zhang, Lujun; Bao, Ande

2012-01-01

Liposomes are effective lipid nanoparticle drug delivery systems, which can also be functionalized with non-invasive multimodality imaging agents with each modality providing distinct information and having synergistic advantages in diagnosis, monitoring of disease treatment, and evaluation of liposomal drug pharmacokinetics. We designed and constructed a multifunctional theranostic liposomal drug delivery system, which integrated multimodality magnetic resonance (MR), near-infrared (NIR) fluorescent and nuclear imaging of liposomal drug delivery, and therapy monitoring and prediction. The pre-manufactured liposomes were composed of DSPC/cholesterol/Gd-DOTADSPE/DOTA-DSPE with the molar ratio of 39:35:25:1 and having ammonium sulfate/pH gradient. A lipidized NIR fluorescent tracer, IRDye-DSPE, was effectively post-inserted into the pre-manufactured liposomes. Doxorubicin could be effectively post-loaded into the multifunctional liposomes. The multifunctional doxorubicin-liposomes could also be stably radiolabeled with 99mTc or 64Cu for single photon emission computed tomography (SPECT) or positron emission tomography (PET) imaging, respectively. MR images displayed the high resolution micro-intratumoral distribution of the liposomes in squamous cell carcinoma of head and neck (SCCHN) tumor xenografts in nude rats after intratumoral injection. NIR fluorescent, SPECT and PET images also clearly showed either the high intratumoral retention or distribution of the multifunctional liposomes. This multifunctional drug carrying liposome system is promising for disease theranostics allowing non-invasive multimodality NIR fluorescent, MR, SPECT and PET imaging of their in vivo behavior and capitalizing on the inherent advantages of each modality. PMID:22577859

Comparison of conventional and cadmium-zinc-telluride single-photon emission computed tomography for analysis of thallium-201 myocardial perfusion imaging: an exploratory study in normal databases for different ethnicities.

PubMed

Ishihara, Masaru; Onoguchi, Masahisa; Taniguchi, Yasuyo; Shibutani, Takayuki

2017-12-01

The aim of this study was to clarify the differences in thallium-201-chloride (thallium-201) myocardial perfusion imaging (MPI) scans evaluated by conventional anger-type single-photon emission computed tomography (conventional SPECT) versus cadmium-zinc-telluride SPECT (CZT SPECT) imaging in normal databases for different ethnic groups. MPI scans from 81 consecutive Japanese patients were examined using conventional SPECT and CZT SPECT and analyzed with the pre-installed quantitative perfusion SPECT (QPS) software. We compared the summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for the two SPECT devices. For a normal MPI reference, we usually use Japanese databases for MPI created by the Japanese Society of Nuclear Medicine, which can be used with conventional SPECT but not with CZT SPECT. In this study, we used new Japanese normal databases constructed in our institution to compare conventional and CZT SPECT. Compared with conventional SPECT, CZT SPECT showed lower SSS (p < 0.001), SRS (p = 0.001), and SDS (p = 0.189) using the pre-installed SPECT database. In contrast, CZT SPECT showed no significant difference from conventional SPECT in QPS analysis using the normal databases from our institution. Myocardial perfusion analyses by CZT SPECT should be evaluated using normal databases based on the ethnic group being evaluated.

Nanoparticles for cancer imaging: The good, the bad, and the promise

PubMed Central

Chapman, Sandra; Dobrovolskaia, Marina; Farahani, Keyvan; Goodwin, Andrew; Joshi, Amit; Lee, Hakho; Meade, Thomas; Pomper, Martin; Ptak, Krzysztof; Rao, Jianghong; Singh, Ravi; Sridhar, Srinivas; Stern, Stephan; Wang, Andrew; Weaver, John B.; Woloschak, Gayle; Yang, Lily

2014-01-01

Summary Recent advances in molecular imaging and nanotechnology are providing new opportunities for biomedical imaging with great promise for the development of novel imaging agents. The unique optical, magnetic, and chemical properties of materials at the scale of nanometers allow the creation of imaging probes with better contrast enhancement, increased sensitivity, controlled biodistribution, better spatial and temporal information, multi-functionality and multi-modal imaging across MRI, PET, SPECT, and ultrasound. These features could ultimately translate to clinical advantages such as earlier detection, real time assessment of disease progression and personalized medicine. However, several years of investigation into the application of these materials to cancer research has revealed challenges that have delayed the successful application of these agents to the field of biomedical imaging. Understanding these challenges is critical to take full advantage of the benefits offered by nano-sized imaging agents. Therefore, this article presents the lessons learned and challenges encountered by a group of leading researchers in this field, and suggests ways forward to develop nanoparticle probes for cancer imaging. Published by Elsevier Ltd. PMID:25419228

Quantitative Comparison of PET and Bremsstrahlung SPECT for Imaging the In Vivo Yttrium-90 Microsphere Distribution after Liver Radioembolization

PubMed Central

Elschot, Mattijs; Vermolen, Bart J.; Lam, Marnix G. E. H.; de Keizer, Bart; van den Bosch, Maurice A. A. J.; de Jong, Hugo W. A. M.

2013-01-01

Background After yttrium-90 (90Y) microsphere radioembolization (RE), evaluation of extrahepatic activity and liver dosimetry is typically performed on 90Y Bremsstrahlung SPECT images. Since these images demonstrate a low quantitative accuracy, 90Y PET has been suggested as an alternative. The aim of this study is to quantitatively compare SPECT and state-of-the-art PET on the ability to detect small accumulations of 90Y and on the accuracy of liver dosimetry. Methodology/Principal Findings SPECT/CT and PET/CT phantom data were acquired using several acquisition and reconstruction protocols, including resolution recovery and Time-Of-Flight (TOF) PET. Image contrast and noise were compared using a torso-shaped phantom containing six hot spheres of various sizes. The ability to detect extra- and intrahepatic accumulations of activity was tested by quantitative evaluation of the visibility and unique detectability of the phantom hot spheres. Image-based dose estimates of the phantom were compared to the true dose. For clinical illustration, the SPECT and PET-based estimated liver dose distributions of five RE patients were compared. At equal noise level, PET showed higher contrast recovery coefficients than SPECT. The highest contrast recovery coefficients were obtained with TOF PET reconstruction including resolution recovery. All six spheres were consistently visible on SPECT and PET images, but PET was able to uniquely detect smaller spheres than SPECT. TOF PET-based estimates of the dose in the phantom spheres were more accurate than SPECT-based dose estimates, with underestimations ranging from 45% (10-mm sphere) to 11% (37-mm sphere) for PET, and 75% to 58% for SPECT, respectively. The differences between TOF PET and SPECT dose-estimates were supported by the patient data. Conclusions/Significance In this study we quantitatively demonstrated that the image quality of state-of-the-art PET is superior over Bremsstrahlung SPECT for the assessment of the 90Y microsphere distribution after radioembolization. PMID:23405207

Performance of a high-sensitivity dedicated cardiac SPECT scanner for striatal uptake quantification in the brain based on analysis of projection data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Mi-Ae; Moore, Stephen C.; McQuaid, Sarah J.

Purpose: The authors have previously reported the advantages of high-sensitivity single-photon emission computed tomography (SPECT) systems for imaging structures located deep inside the brain. DaTscan (Isoflupane I-123) is a dopamine transporter (DaT) imaging agent that has shown potential for early detection of Parkinson disease (PD), as well as for monitoring progression of the disease. Realizing the full potential of DaTscan requires efficient estimation of striatal uptake from SPECT images. They have evaluated two SPECT systems, a conventional dual-head gamma camera with low-energy high-resolution collimators (conventional) and a dedicated high-sensitivity multidetector cardiac imaging system (dedicated) for imaging tasks related to PD.more » Methods: Cramer-Rao bounds (CRB) on precision of estimates of striatal and background activity concentrations were calculated from high-count, separate acquisitions of the compartments (right striata, left striata, background) of a striatal phantom. CRB on striatal and background activity concentration were calculated from essentially noise-free projection datasets, synthesized by scaling and summing the compartment projection datasets, for a range of total detected counts. They also calculated variances of estimates of specific-to-nonspecific binding ratios (BR) and asymmetry indices from these values using propagation of error analysis, as well as the precision of measuring changes in BR on the order of the average annual decline in early PD. Results: Under typical clinical conditions, the conventional camera detected 2 M counts while the dedicated camera detected 12 M counts. Assuming a normal BR of 5, the standard deviation of BR estimates was 0.042 and 0.021 for the conventional and dedicated system, respectively. For an 8% decrease to BR = 4.6, the signal-to-noise ratio were 6.8 (conventional) and 13.3 (dedicated); for a 5% decrease, they were 4.2 (conventional) and 8.3 (dedicated). Conclusions: This implies that PD can be detected earlier with the dedicated system than with the conventional system; therefore, earlier identification of PD progression should be possible with the high-sensitivity dedicated SPECT camera.« less

Effect of attenuation correction on image quality in emission tomography

NASA Astrophysics Data System (ADS)

Denisova, N. V.; Ondar, M. M.

2017-10-01

In this paper, mathematical modeling and computer simulations of myocardial perfusion SPECT imaging are performed. The main factors affecting the quality of reconstructed images in SPECT are anatomical structures, the diastolic volume of a myocardium and attenuation of gamma rays. The purpose of the present work is to study the effect of attenuation correction on image quality in emission tomography. The basic 2D model describing a Tc-99m distribution in a transaxial slice of the thoracic part of a patient body was designed. This model was used to construct four phantoms simulated various anatomical shapes: 2 male and 2 female patients with normal, obese and subtle physique were included in the study. Data acquisition model which includes the effect of non-uniform attenuation, collimator-detector response and Poisson statistics was developed. The projection data were calculated for 60 views in accordance with the standard myocardial perfusion SPECT imaging protocol. Reconstructions of images were performed using the OSEM algorithm which is widely used in modern SPECT systems. Two types of patient's examination procedures were simulated: SPECT without attenuation correction and SPECT/CT with attenuation correction. The obtained results indicate a significant effect of the attenuation correction on the SPECT images quality.

IQ-SPECT for thallium-201 myocardial perfusion imaging: effect of normal databases on quantification.

PubMed

Konishi, Takahiro; Nakajima, Kenichi; Okuda, Koichi; Yoneyama, Hiroto; Matsuo, Shinro; Shibutani, Takayuki; Onoguchi, Masahisa; Kinuya, Seigo

2017-07-01

Although IQ-single-photon emission computed tomography (SPECT) provides rapid acquisition and attenuation-corrected images, the unique technology may create characteristic distribution different from the conventional imaging. This study aimed to compare the diagnostic performance of IQ-SPECT using Japanese normal databases (NDBs) with that of the conventional SPECT for thallium-201 ( 201 Tl) myocardial perfusion imaging (MPI). A total of 36 patients underwent 1-day 201 Tl adenosine stress-rest MPI. Images were acquired with IQ-SPECT at approximately one-quarter of the standard time of conventional SPECT. Projection data acquired with the IQ-SPECT system were reconstructed via an ordered subset conjugate gradient minimizer method with or without scatter and attenuation correction (SCAC). Projection data obtained using the conventional SPECT were reconstructed via a filtered back projection method without SCAC. The summed stress score (SSS) was calculated using NDBs created by the Japanese Society of Nuclear Medicine working group, and scores were compared between IQ-SPECT and conventional SPECT using the acquisition condition-matched NDBs. The diagnostic performance of the methods for the detection of coronary artery disease was also compared. SSSs were 6.6 ± 8.2 for the conventional SPECT, 6.6 ± 9.4 for IQ-SPECT without SCAC, and 6.5 ± 9.7 for IQ-SPECT with SCAC (p = n.s. for each comparison). The SSS showed a strong positive correlation between conventional SPECT and IQ-SPECT (r = 0.921 and p < 0.0001), and the correlation between IQ-SPECT with and without SCAC was also good (r = 0.907 and p < 0.0001). Regarding diagnostic performance, the sensitivity, specificity, and accuracy were 80.8, 78.9, and 79.4%, respectively, for the conventional SPECT; 80.8, 80.3, and 82.0%, respectively, for IQ-SPECT without SCAC; and 88.5, 86.8, and 87.3%, respectively, for IQ-SPECT with SCAC, respectively. The area under the curve obtained via receiver operating characteristic analysis were 0.77, 0.80, and 0.86 for conventional SPECT, IQ-SPECT without SCAC, and IQ-SPECT with SCAC, respectively (p = n.s. for each comparison). When appropriate NDBs were used, the diagnostic performance of 201 Tl IQ-SPECT was comparable with that of the conventional system regardless of different characteristics of myocardial accumulation in the conventional system.

High-resolution single photon planar and spect imaging of brain and neck employing a system of two co-registered opposed gamma imaging heads

DOEpatents

Majewski, Stanislaw [Yorktown, VA; Proffitt, James [Newport News, VA

2011-12-06

A compact, mobile, dedicated SPECT brain imager that can be easily moved to the patient to provide in-situ imaging, especially when the patient cannot be moved to the Nuclear Medicine imaging center. As a result of the widespread availability of single photon labeled biomarkers, the SPECT brain imager can be used in many locations, including remote locations away from medical centers. The SPECT imager improves the detection of gamma emission from the patient's head and neck area with a large field of view. Two identical lightweight gamma imaging detector heads are mounted to a rotating gantry and precisely mechanically co-registered to each other at 180 degrees. A unique imaging algorithm combines the co-registered images from the detector heads and provides several SPECT tomographic reconstructions of the imaged object thereby improving the diagnostic quality especially in the case of imaging requiring higher spatial resolution and sensitivity at the same time.

The use of 99mTc-Al2O3 for detection of sentinel lymph nodes in cervical cancer patients

NASA Astrophysics Data System (ADS)

Sinilkin, I. G.; Chernov, V. I.; Lyapunov, A. Yu; Medvedeva, A. A.; Zelchan, R. V.; Chernyshova, A. L.; Kolomiets, L. A.

2016-06-01

The purpose of the study was to evaluate the feasibility of using 99mTc-Al2O3- based radiopharmaceutical, a novel molecular imaging agent for sentinel lymph node detection in patients with invasive cervical cancer. The study included 23 cervical cancer patients (TlaNxMx- T2bNxMx) treated at the Tomsk Cancer Research Institute. At 18 hours before surgery, 80 MBq of the 99mTc-Al2O3 were injected peritumorally, followed by single-photon emission computed tomography (SPECT) of the pelvis and intraoperative SLN identification. Twenty-seven SLNs were detected by SPECT, and 34 SLNs were identified by intraoperative gamma probe. The total number of identified SLNs per patient ranged from 1 to 3(the mean number of SLNs was 1.4 per patient). The most common site for SLN detection was the external iliac region (57.2%), followed by the internal iliac, obturator, presacral and retrosacral regions (they amounted to 14%, respectively),and the parametrial region (1%). Sensitivity in detecting SLNs was 100% for intraoperative SLN identification and 79% for SPECT image.

The first experience of using 99mTc-Al2O3-based radiopharmaceutical for the detection of sentinel lymph nodes in cervical cancer patients

NASA Astrophysics Data System (ADS)

Sinilkin, I. G.; Chernov, V. I.; Lyapunov, A. Yu.; Medvedeva, A. A.; Zelchan, R. V.; Chernyshova, A. L.; Kolomiets, L. A.

2016-08-01

The purpose of the study was to evaluate the feasibility of using 99mTc-Al2O3-based radiopharmaceutical, a novel molecular imaging agent for sentinel lymph node detection in patients with invasive cervical cancer. The study included 23 cervical cancer patients (T1aNxMx-T2bNxMx) treated at the Tomsk Cancer Research Institute. In the 18 hours before surgery, 80 MBq of the 99mTc-Al2O3 in peritumoral injected, followed by single-photon emission computed tomography (SPECT) of the pelvis and intraoperative SLN identification. Twenty-seven SLNs were detected by SPECT, and 34 SLNs were identified by intraoperative gamma probe. The total number of identified SLNs per patient ranged from 1 to 3 (the mean number of SLNs was 1.4 per patient). The most common site for SLN detection was the external iliac region (57.2%), followed by the internal iliac (14%), obturator (14%), presacral and retrosacral regions (14%), and the parametrial region (1%). Sensitivity in detecting SLNs was 100% for intraoperative SLN identification and 79% for SPECT image.

Comparison of 18F SPECT with PET in myocardial imaging: a realistic thorax-cardiac phantom study.

PubMed

Knešaurek, Karin; Machac, Josef

2006-10-31

Positron emission tomography (PET) imaging with fluorine-18 (18F) Fluorodeoxyglucose (FDG) and flow tracer such as Rubidium-82 (82Rb) is an established method for evaluating an ischemic but viable myocardium. However, the high cost of PET imaging restricts its wider clinical use. Therefore, less expensive 18F FDG single photon emission computed tomography (SPECT) imaging has been considered as an alternative to 18F FDG PET imaging. The purpose of the work is to compare SPECT with PET in myocardial perfusion/viability imaging. A nonuniform RH-2 thorax-heart phantom was used in the SPECT and PET acquisitions. Three inserts, 3 cm, 2 cm and 1 cm in diameter, were placed in the left ventricular (LV) wall to simulate infarcts. The phantom acquisition was performed sequentially with 7.4 MBq of 18F and 22.2 MBq of Technetium-99m (99mTc) in the SPECT study and with 7.4 MBq of 18F and 370 MBq of 82Rb in the PET study. SPECT and PET data were processed using standard reconstruction software provided by vendors. Circumferential profiles of the short-axis slices, the contrast and viability of the inserts were used to evaluate the SPECT and PET images. The contrast for 3 cm, 2 cm and 1 cm inserts were for 18F PET data, 1.0 +/- 0.01, 0.67 +/- 0.02 and 0.25 +/- 0.01, respectively. For 82Rb PET data, the corresponding contrast values were 0.61 +/- 0.02, 0.37 +/- 0.02 and 0.19 +/- 0.01, respectively. For 18F SPECT the contrast values were, 0.31 +/- 0.03 and 0.20 +/- 0.05 for 3 cm and 2 cm inserts, respectively. For 99mTc SPECT the contrast values were, 0.63 +/- 0.04 and 0.24 +/- 0.05 for 3 cm and 2 cm inserts respectively. In SPECT, the 1 cm insert was not detectable. In the SPECT study, all three inserts were falsely diagnosed as "viable", while in the PET study, only the 1 cm insert was diagnosed falsely "viable". For smaller defects the 99mTc/18F SPECT imaging cannot entirely replace the more expensive 82Rb/18F PET for myocardial perfusion/viability imaging, due to poorer image spatial resolution and poorer defect contrast.

SPECT data acquisition and image reconstruction in a stationary small animal SPECT/MRI system

NASA Astrophysics Data System (ADS)

Xu, Jingyan; Chen, Si; Yu, Jianhua; Meier, Dirk; Wagenaar, Douglas J.; Patt, Bradley E.; Tsui, Benjamin M. W.

2010-04-01

The goal of the study was to investigate data acquisition strategies and image reconstruction methods for a stationary SPECT insert that can operate inside an MRI scanner with a 12 cm bore diameter for simultaneous SPECT/MRI imaging of small animals. The SPECT insert consists of 3 octagonal rings of 8 MR-compatible CZT detectors per ring surrounding a multi-pinhole (MPH) collimator sleeve. Each pinhole is constructed to project the field-of-view (FOV) to one CZT detector. All 24 pinholes are focused to a cylindrical FOV of 25 mm in diameter and 34 mm in length. The data acquisition strategies we evaluated were optional collimator rotations to improve tomographic sampling; and the image reconstruction methods were iterative ML-EM with and without compensation for the geometric response function (GRF) of the MPH collimator. For this purpose, we developed an analytic simulator that calculates the system matrix with the GRF models of the MPH collimator. The simulator was used to generate projection data of a digital rod phantom with pinhole aperture sizes of 1 mm and 2 mm and with different collimator rotation patterns. Iterative ML-EM reconstruction with and without GRF compensation were used to reconstruct the projection data from the central ring of 8 detectors only, and from all 24 detectors. Our results indicated that without GRF compensation and at the default design of 24 projection views, the reconstructed images had significant artifacts. Accurate GRF compensation substantially improved the reconstructed image resolution and reduced image artifacts. With accurate GRF compensation, useful reconstructed images can be obtained using 24 projection views only. This last finding potentially enables dynamic SPECT (and/or MRI) studies in small animals, one of many possible application areas of the SPECT/MRI system. Further research efforts are warranted including experimentally measuring the system matrix for improved geometrical accuracy, incorporating the co-registered MRI image in SPECT reconstruction, and exploring potential applications of the simultaneous SPECT/MRI SA system including dynamic SPECT studies.

Onboard functional and molecular imaging: A design investigation for robotic multipinhole SPECT

PubMed Central

Bowsher, James; Yan, Susu; Roper, Justin; Giles, William; Yin, Fang-Fang

2014-01-01

Purpose: Onboard imaging—currently performed primarily by x-ray transmission modalities—is essential in modern radiation therapy. As radiation therapy moves toward personalized medicine, molecular imaging, which views individual gene expression, may also be important onboard. Nuclear medicine methods, such as single photon emission computed tomography (SPECT), are premier modalities for molecular imaging. The purpose of this study is to investigate a robotic multipinhole approach to onboard SPECT. Methods: Computer-aided design (CAD) studies were performed to assess the feasibility of maneuvering a robotic SPECT system about a patient in position for radiation therapy. In order to obtain fast, high-quality SPECT images, a 49-pinhole SPECT camera was designed which provides high sensitivity to photons emitted from an imaging region of interest. This multipinhole system was investigated by computer-simulation studies. Seventeen hot spots 10 and 7 mm in diameter were placed in the breast region of a supine female phantom. Hot spot activity concentration was six times that of background. For the 49-pinhole camera and a reference, more conventional, broad field-of-view (FOV) SPECT system, projection data were computer simulated for 4-min scans and SPECT images were reconstructed. Hot-spot localization was evaluated using a nonprewhitening forced-choice numerical observer. Results: The CAD simulation studies found that robots could maneuver SPECT cameras about patients in position for radiation therapy. In the imaging studies, most hot spots were apparent in the 49-pinhole images. Average localization errors for 10-mm- and 7-mm-diameter hot spots were 0.4 and 1.7 mm, respectively, for the 49-pinhole system, and 3.1 and 5.7 mm, respectively, for the reference broad-FOV system. Conclusions: A robot could maneuver a multipinhole SPECT system about a patient in position for radiation therapy. The system could provide onboard functional and molecular imaging with 4-min scan times. PMID:24387490

Onboard functional and molecular imaging: A design investigation for robotic multipinhole SPECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowsher, James, E-mail: james.bowsher@duke.edu; Giles, William; Yin, Fang-Fang

2014-01-15

Purpose: Onboard imaging—currently performed primarily by x-ray transmission modalities—is essential in modern radiation therapy. As radiation therapy moves toward personalized medicine, molecular imaging, which views individual gene expression, may also be important onboard. Nuclear medicine methods, such as single photon emission computed tomography (SPECT), are premier modalities for molecular imaging. The purpose of this study is to investigate a robotic multipinhole approach to onboard SPECT. Methods: Computer-aided design (CAD) studies were performed to assess the feasibility of maneuvering a robotic SPECT system about a patient in position for radiation therapy. In order to obtain fast, high-quality SPECT images, a 49-pinholemore » SPECT camera was designed which provides high sensitivity to photons emitted from an imaging region of interest. This multipinhole system was investigated by computer-simulation studies. Seventeen hot spots 10 and 7 mm in diameter were placed in the breast region of a supine female phantom. Hot spot activity concentration was six times that of background. For the 49-pinhole camera and a reference, more conventional, broad field-of-view (FOV) SPECT system, projection data were computer simulated for 4-min scans and SPECT images were reconstructed. Hot-spot localization was evaluated using a nonprewhitening forced-choice numerical observer. Results: The CAD simulation studies found that robots could maneuver SPECT cameras about patients in position for radiation therapy. In the imaging studies, most hot spots were apparent in the 49-pinhole images. Average localization errors for 10-mm- and 7-mm-diameter hot spots were 0.4 and 1.7 mm, respectively, for the 49-pinhole system, and 3.1 and 5.7 mm, respectively, for the reference broad-FOV system. Conclusions: A robot could maneuver a multipinhole SPECT system about a patient in position for radiation therapy. The system could provide onboard functional and molecular imaging with 4-min scan times.« less

TH-E-BRF-02: 4D-CT Ventilation Image-Based IMRT Plans Are Dosimetrically Comparable to SPECT Ventilation Image-Based Plans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kida, S; University of Tokyo Hospital, Bunkyo, Tokyo; Bal, M

Purpose: An emerging lung ventilation imaging method based on 4D-CT can be used in radiotherapy to selectively avoid irradiating highly-functional lung regions, which may reduce pulmonary toxicity. Efforts to validate 4DCT ventilation imaging have been focused on comparison with other imaging modalities including SPECT and xenon CT. The purpose of this study was to compare 4D-CT ventilation image-based functional IMRT plans with SPECT ventilation image-based plans as reference. Methods: 4D-CT and SPECT ventilation scans were acquired for five thoracic cancer patients in an IRB-approved prospective clinical trial. The ventilation images were created by quantitative analysis of regional volume changes (amore » surrogate for ventilation) using deformable image registration of the 4D-CT images. A pair of 4D-CT ventilation and SPECT ventilation image-based IMRT plans was created for each patient. Regional ventilation information was incorporated into lung dose-volume objectives for IMRT optimization by assigning different weights on a voxel-by-voxel basis. The objectives and constraints of the other structures in the plan were kept identical. The differences in the dose-volume metrics have been evaluated and tested by a paired t-test. SPECT ventilation was used to calculate the lung functional dose-volume metrics (i.e., mean dose, V20 and effective dose) for both 4D-CT ventilation image-based and SPECT ventilation image-based plans. Results: Overall there were no statistically significant differences in any dose-volume metrics between the 4D-CT and SPECT ventilation imagebased plans. For example, the average functional mean lung dose of the 4D-CT plans was 26.1±9.15 (Gy), which was comparable to 25.2±8.60 (Gy) of the SPECT plans (p = 0.89). For other critical organs and PTV, nonsignificant differences were found as well. Conclusion: This study has demonstrated that 4D-CT ventilation image-based functional IMRT plans are dosimetrically comparable to SPECT ventilation image-based plans, providing evidence to use 4D-CT ventilation imaging for clinical applications. Supported in part by Free to Breathe Young Investigator Research Grant and NIH/NCI R01 CA 093626. The authors thank Philips Radiation Oncology Systems for the Pinnacle3 treatment planning systems.« less

Blood-pool SPECT in addition to bone SPECT in the viability assessment in mandibular reconstruction.

PubMed

Aydogan, F; Akbay, E; Cevik, C; Kalender, E

2014-01-01

The assessment of the postoperative viability of vascularized and non-vascularized grafts used in the reconstruction of mandibular defects due to trauma and surgical reasons is a major problem in maxillofacial surgery. In the present study, we evaluated the feasibility and image quality of blood-pool SPECT, which is used for the first time in the literature here in the assessment of mandibular reconstruction, in addition to non-invasive bone scintigraphy and bone SPECT. We also evaluated whether it would be useful in clinical prediction. Micro-vascularized and non-vascularized bone grafts were used in 12 Syrian men with maxillofacial trauma. Between days 5-7 after surgery, three-phase bone scintigraphy, blood-pool SPECT and delayed bone SPECT scans were performed. After month 6, the patients were assessed by control CT scans. Of the non-vascularized grafts, one graft was reported as non-viable at week one. At month 6, graft resorption was demonstrated on the CT images. The remaining non-vascularized grafts and all of the micro-vascularized grafts were considered to be viable according to delayed bone SPECT and blood-pool SPECT images. However, only the anterior and posterior ends could be clearly assessed on delayed SPECT images, while blood-pool SPECT images allowed the clear assessment of the entire graft. The combined use of blood-pool and delayed SPECT scans could allow for better assessment of graft viability in the early period, and can provide more detailed information to clinicians about prognosis in the follow-up of patients undergoing mandibular graft reconstruction.

Patient- and clinician-reported satisfaction with pharmacological stress agents for single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).

PubMed

Hudgens, Stacie; Breeze, Janis; Spalding, James

2013-01-01

The objective of this study was to compare clinician and patient measures of satisfaction with two pharmacological stress agents (PSA), regadenoson and dipyridamole, used in Single Photon Emission Computed Tomography (SPECT) Myocardial Perfusion Imaging (MPI). This observational study included patients who had undergone SPECT MPI with regadenoson or dipyridamole, as well as the clinician/clinical technologist who performed the test. Mean scores for individual item and domain scores of the main outcome measures were computed as well as the effect sizes (ES) of the mean difference in scores between treatment groups. Statistical significance of the mean item and domain score differences were assessed via Mann-Whitney tests. Two self-report questionnaires which had beeb previously developed and validated: Patient Satisfaction/Preference Questionnaire (PSPQ) and Clinician Satisfaction/Preference Questionnaire (CSPQ). A total of 87 patients (68 received regadenoson, 19 received dipyridamole) and nine clinicians/clinical technologists took part in the study. Patients had a mean age of 66.8 ± 12.2 years, and 56.3% were male. Compared to dipyridamole, use of regadenoson was associated with greater clinician satisfaction on all items and domains of the CSPQ (p < 0.001 for all comparisons). Among patients, regadenoson was associated with less bother and greater satisfaction than dipyridamole for all items on the PSPQ. These patients reported less stinging at the injection site (ES = -0.66) and less nervousness during injection (ES = -0.60). The PSPQ found that regadenoson patients were more satisfied with their PSA than dipyridamole patients in all areas. This study utilized a relatively small sample size of dipyridamole patients and lacked an adenosine group. A broader sampling of professionals would also help demonstrate generalizability. Both patients and clinicians reported higher satisfaction with regadenoson compared to dipyridamole for SPECT-MPI. Clinicians were particularly satisfied with the preparation and administration aspects of the drug, while patients rated it highly on convenience and reduced incidence of side-effects.

SPECT/CT with 99mTc-MAA in radioembolization with 90Y microspheres in patients with hepatocellular cancer.

PubMed

Hamami, Monia E; Poeppel, Thorsten D; Müller, Stephan; Heusner, Till; Bockisch, Andreas; Hilgard, Philipp; Antoch, Gerald

2009-05-01

Radioembolization with (90)Y microspheres is a novel treatment for hepatic tumors. Generally, hepatic arteriography and (99m)Tc-macroaggregated albumin (MAA) scanning are performed before selective internal radiation therapy to detect extrahepatic shunting to the lung or the gastrointestinal tract. Whereas previous studies have used only planar or SPECT scans, the present study used (99m)Tc-MAA SPECT/CT scintigraphy (SPECT with integrated low-dose CT) to evaluate whether SPECT/CT and additional diagnostic contrast-enhanced CT before radioembolization with (90)Y microspheres are superior to SPECT or planar imaging alone for detection of gastrointestinal shunting. In a prospective study, we enrolled 58 patients (mean age, 66 y; SD, 12 y; 10 women and 48 men) with hepatocellular carcinoma who underwent hepatic arteriography and scintigraphy with (99m)Tc-MAA using planar imaging, SPECT, and SPECT with integrated low-dose CT of the upper abdomen (acquired with a hybrid SPECT/CT camera). The ability of the different imaging modalities to detect extrahepatic MAA shunting was compared. Patient follow-up of a mean of 180 d served as the standard of reference. Gastrointestinal shunting was revealed by planar imaging in 4, by SPECT in 9, and by SPECT/CT in 16 of the 68 examinations. For planar imaging, the sensitivity for detection of gastrointestinal shunting was 25%, the specificity 87%, and the accuracy 72%. For SPECT without CT, the sensitivity was 56%, the specificity 87%, and the accuracy 79%. SPECT with CT fusion had a sensitivity of 100%, a specificity of 94%, and an accuracy of 96%. In 3 patients, MAA deposits in the portal vein could accurately be attributed to tumor thrombus only with additional information from contrast-enhanced CT. The follow-up did not show any gastrointestinal complications. SPECT with integrated low-dose CT using (99m)Tc-MAA is beneficial in radioembolization with (90)Y microspheres because it increases the sensitivity and specificity of (99m)Tc-MAA SPECT when detecting extrahepatic arterial shunting. The overall low risk of gastrointestinal complications in radioembolization may therefore be further reduced by SPECT/CT.

Usefulness of Tc-99m MDP spine SPECT imaging in differentiating malignant from benign lesions in cancer patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryu, J.S.; Moon, D.H.; Shin, M.J.

1994-05-01

Solitary or a few spinal abnormalities on planar bone scan pose a dilemma in cancer patients. The purpose of this study was to evaluate the usefulness of spine SPECT imaging in differential diagnosis of malignant and benign lesion. Subjects were 54 adult patients with solitary or a few equivocal vertebral lesions on planar bone scan. Spine SPECT imaging was obtained by a triple head SPECT system (TRIAD, Trionix). The final diagnoses were based on data from biopsy, other imaging studies, or minimum 1 year of follow up. Two blind observers reviewed the planar image first, then both planar and SPECTmore » images. The uptake patterns on SPECT images were analyzed, and the diagnostic performance was evaluated by the ROC analysis. Thirty three lesions of 22 patients were malignant, and 60 lesions of 32 patients were benign. Common characteristic patterns of malignant lesions were focal or segmental hot uptake in the body, hot uptake in the body and pedicle, and cold defect with surrounding hot uptake in the vertebra. Whereas marginal protruding hot uptakes in endplate, and hot uptakes in facet joints were benign. The ROC analysis showed that SPECT improved the diagnostic performance (the area under the ROC curve of two observers for planar image 0.903 and 0.791, for the combination of planar and SPECT : 0.950 and 0.976). In conclusion, the uptake pattern recognition in spine SPECT provides useful information for differential diagnosis of malignant and benign lesions in vertebra. Spine SPECT is a valuable complement in cancer patients with inconclusive findings on planar bone scan.« less

Optimized 3D stitching algorithm for whole body SPECT based on transition error minimization (TEM)

NASA Astrophysics Data System (ADS)

Cao, Xinhua; Xu, Xiaoyin; Voss, Stephan

2017-02-01

Standard Single Photon Emission Computed Tomography (SPECT) has a limited field of view (FOV) and cannot provide a 3D image of an entire long whole body SPECT. To produce a 3D whole body SPECT image, two to five overlapped SPECT FOVs from head to foot are acquired and assembled using image stitching. Most commercial software from medical imaging manufacturers applies a direct mid-slice stitching method to avoid blurring or ghosting from 3D image blending. Due to intensity changes across the middle slice of overlapped images, direct mid-slice stitching often produces visible seams in the coronal and sagittal views and maximal intensity projection (MIP). In this study, we proposed an optimized algorithm to reduce the visibility of stitching edges. The new algorithm computed, based on transition error minimization (TEM), a 3D stitching interface between two overlapped 3D SPECT images. To test the suggested algorithm, four studies of 2-FOV whole body SPECT were used and included two different reconstruction methods (filtered back projection (FBP) and ordered subset expectation maximization (OSEM)) as well as two different radiopharmaceuticals (Tc-99m MDP for bone metastases and I-131 MIBG for neuroblastoma tumors). Relative transition errors of stitched whole body SPECT using mid-slice stitching and the TEM-based algorithm were measured for objective evaluation. Preliminary experiments showed that the new algorithm reduced the visibility of the stitching interface in the coronal, sagittal, and MIP views. Average relative transition errors were reduced from 56.7% of mid-slice stitching to 11.7% of TEM-based stitching. The proposed algorithm also avoids blurring artifacts by preserving the noise properties of the original SPECT images.

Radiolabeled Peptide Scaffolds for PET/SPECT - Optical in Vivo Imaging of Carbohydrate-Lectin Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deutscher, Susan

2014-09-30

The objective of this research is to develop phage display-selected peptides into radio- and fluoresecently- labeled scaffolds for the multimodal imaging of carbohydrate-lectin interactions. While numerous protein and receptor systems are being explored for the development of targeted imaging agents, the targeting and analysis of carbohydrate-lectin complexes in vivo remains relatively unexplored. Antibodies, nanoparticles, and peptides are being developed that target carbohydrate-lectin complexes in living systems. However, antibodies and nanoparticles often suffer from slow clearance and toxicity problems. Peptides are attractive alternative vehicles for the specific delivery of radionuclides or fluorophores to sites of interest in vivo, although, because ofmore » their size, uptake and retention may be less than antibodies. We have selected high affinity peptides that bind a specific carbohydrate-lectin complex involved in cell-cell adhesion and cross-linking using bacteriophage (phage) display technologies (1,2). These peptides have allowed us to probe the role of these antigens in cell adhesion. Fluorescent versions of the peptides have been developed for optical imaging and radiolabeled versions have been used in single photon emission computed tomography (SPECT) and positron emission tomography (PET) in vivo imaging (3-6). A benefit in employing the radiolabeled peptides in SPECT and PET is that these imaging modalities are widely used in living systems and offer deep tissue sensitivity. Radiolabeled peptides, however, often exhibit poor stability and high kidney uptake in vivo. Conversely, optical imaging is sensitive and offers good spatial resolution, but is not useful for deep tissue penetration and is semi-quantitative. Thus, multimodality imaging that relies on the strengths of both radio- and optical- imaging is a current focus for development of new in vivo imaging agents. We propose a novel means to improve the efficacy of radiolabeled and fluorescently labeled peptides, including our lectin/carbohydrate- targeting peptides, by displaying the targeting epitopes on small ~29 amino acid cyclic plant protein scaffolds known as cyclotides. Cyclotides are extremely stable molecules with long serum half-lives and low kidney uptake (7). More than one copy of the peptide can be engineered into the cyclotide loops, thus increasing the avidity of the peptide construct for its target.« less

Preclinical imaging characteristics and quantification of Platinum-195m SPECT.

PubMed

Aalbersberg, E A; de Wit-van der Veen, B J; Zwaagstra, O; Codée-van der Schilden, K; Vegt, E; Vogel, Wouter V

2017-08-01

In vivo biodistribution imaging of platinum-based compounds may allow better patient selection for treatment with chemo(radio)therapy. Radiolabeling with Platinum-195m ( 195m Pt) allows SPECT imaging, without altering the chemical structure or biological activity of the compound. We have assessed the feasibility of 195m Pt SPECT imaging in mice, with the aim to determine the image quality and accuracy of quantification for current preclinical imaging equipment. Enriched (>96%) 194 Pt was irradiated in the High Flux Reactor (HFR) in Petten, The Netherlands (NRG). A 0.05 M HCl 195m Pt-solution with a specific activity of 33 MBq/mg was obtained. Image quality was assessed for the NanoSPECT/CT (Bioscan Inc., Washington DC, USA) and U-SPECT + /CT (MILabs BV, Utrecht, the Netherlands) scanners. A radioactivity-filled rod phantom (rod diameter 0.85-1.7 mm) filled with 1 MBq 195m Pt was scanned with different acquisition durations (10-120 min). Four healthy mice were injected intravenously with 3-4 MBq 195m Pt. Mouse images were acquired with the NanoSPECT for 120 min at 0, 2, 4, or 24 h after injection. Organs were delineated to quantify 195m Pt concentrations. Immediately after scanning, the mice were sacrificed, and the platinum concentration was determined in organs using a gamma counter and graphite furnace - atomic absorption spectroscopy (GF-AAS) as reference standards. A 30-min acquisition of the phantom provided visually adequate image quality for both scanners. The smallest visible rods were 0.95 mm in diameter on the NanoSPECT and 0.85 mm in diameter on the U-SPECT + . The image quality in mice was visually adequate. Uptake was seen in the kidneys with excretion to the bladder, and in the liver, blood, and intestine. No uptake was seen in the brain. The Spearman correlation between SPECT and gamma counter was 0.92, between SPECT and GF-AAS it was 0.84, and between GF-AAS and gamma counter it was0.97 (all p < 0.0001). Preclinical 195m Pt SPECT is feasible with acceptable tracer doses and acquisition times, and provides good image quality and accurate signal quantification.

Noninvasive imaging of experimental lung fibrosis.

PubMed

Zhou, Yong; Chen, Huaping; Ambalavanan, Namasivayam; Liu, Gang; Antony, Veena B; Ding, Qiang; Nath, Hrudaya; Eary, Janet F; Thannickal, Victor J

2015-07-01

Small animal models of lung fibrosis are essential for unraveling the molecular mechanisms underlying human fibrotic lung diseases; additionally, they are useful for preclinical testing of candidate antifibrotic agents. The current end-point measures of experimental lung fibrosis involve labor-intensive histological and biochemical analyses. These measures fail to account for dynamic changes in the disease process in individual animals and are limited by the need for large numbers of animals for longitudinal studies. The emergence of noninvasive imaging technologies provides exciting opportunities to image lung fibrosis in live animals as often as needed and to longitudinally track the efficacy of novel antifibrotic compounds. Data obtained by noninvasive imaging provide complementary information to histological and biochemical measurements. In addition, the use of noninvasive imaging in animal studies reduces animal usage, thus satisfying animal welfare concerns. In this article, we review these new imaging modalities with the potential for evaluation of lung fibrosis in small animal models. Such techniques include micro-computed tomography (micro-CT), magnetic resonance imaging, positron emission tomography (PET), single photon emission computed tomography (SPECT), and multimodal imaging systems including PET/CT and SPECT/CT. It is anticipated that noninvasive imaging will be increasingly used in animal models of fibrosis to gain insights into disease pathogenesis and as preclinical tools to assess drug efficacy.

Creation and characterization of normal myocardial perfusion imaging databases using the IQ·SPECT system.

PubMed

Okuda, Koichi; Nakajima, Kenichi; Matsuo, Shinro; Kondo, Chisato; Sarai, Masayoshi; Horiguchi, Yoriko; Konishi, Takahiro; Onoguchi, Masahisa; Shimizu, Takeshi; Kinuya, Seigo

2017-01-03

Image acquisition by short-time single-photon emission-computed tomography (SPECT) has been made feasible by IQ·SPECT. The aim of this study was to generate normal databases (NDBs) of thallium-201 ( 201 Tl) myocardial perfusion imaging for IQ·SPECT, and characterize myocardial perfusion distribution. We retrospectively enrolled 159 patients with a low likelihood of cardiac diseases from four hospitals in Japan. All patients underwent short-time 201 Tl myocardial perfusion IQ·SPECT with or without attenuation and scatter correction (ACSC) in either supine or prone position. The mean myocardial counts were calculated using 17-segment polar maps. Three NDBs were derived from supine and prone images as well as supine images with ACSC. Differences between the supine and prone positions were observed in the uncorrected sex-segregated NDBs in the mid-inferolateral counts (p ≤ 0.016 for males and p ≤ 0.002 for females). Differences between IQ·SPECT and conventional SPECT were also observed in the mid-anterior, inferolateral, and apical lateral counts (p ≤ 0.009 for males and p ≤ 0.003 for females). Apical low counts attributed to myocardial thinning were observed in the apical anterior and apex segments in the supine IQ·SPECT NDB with ACSC. There were significant differences between uncorrected supine and prone NDBs, between uncorrected supine NDB and supine NDB with ACSC, and between uncorrected supine NDB and conventional SPECT NDB. Understanding the pattern of normal distribution in IQ-SPECT short-time acquisitions with and without ACSC will be helpful for interpretation of imaging findings in patients with coronary artery disease (CAD) or low likelihood of CAD and the NDBs will aid in quantitative analysis.

Value of a Lower-Limb Immobilization Device for Optimization of SPECT/CT Image Fusion.

PubMed

Machado, Joana do Mar F; Monteiro, Marina S; Vieira, Victor Fernandes; Collinot, Jean-Aybert; Prior, John O; Vieira, Lina; Pires-Jorge, José A

2015-06-01

The foot and the ankle are small structures commonly affected by disorders, and their complex anatomy represents a significant diagnostic challenge. By providing information on anatomic and bone structure that cannot be obtained from functional imaging, SPECT/CT image fusion can be particularly useful in increasing diagnostic certainty about bone pathology. However, because of the lengthy duration of a SPECT acquisition, a patient's involuntary movements may lead to misalignment between SPECT and CT images. Patient motion can be reduced using a dedicated patient support. We designed an ankle- and foot-immobilizing device and measured its efficacy at improving image fusion. We enrolled 20 patients who underwent SPECT/CT of the ankle and foot with and without a foot support. The misalignment between SPECT and CT images was computed by manually measuring 14 fiducial markers chosen among anatomic landmarks also visible on bone scintigraphy. ANOVA was performed for statistical analysis. The absolute average difference without and with support was 5.1 ± 5.2 mm (mean ± SD) and 3.1 ± 2.7 mm, respectively, which is significant (P < 0.001). The introduction of the foot support significantly decreased misalignment between SPECT and CT images, which may have a positive clinical influence in the precise localization of foot and ankle pathology. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Reconstruction of truncated TCT and SPECT data from a right-angle dual-camera system for myocardial SPECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsui, B.M.W.; Frey, E.C.; Lalush, D.S.

1996-12-31

We investigated methods to accurately reconstruct 180{degrees} truncated TCT and SPECT projection data obtained from a right-angle dual-camera SPECT system for myocardial SPECT with attenuation compensation. The 180{degrees} data reconstruction methods would permit substantial savings in transmission data acquisition time. Simulation data from the 3D MCAT phantom and clinical data from large patients were used in the evaluation study. Different transmission reconstruction methods including the FBP, transmission ML-EM, transmission ML-SA, and BIT algorithms with and without using the body contour as support, were used in the TCT image reconstructions. The accuracy of both the TCT and attenuation compensated SPECT imagesmore » were evaluated for different degrees of truncation and noise levels. We found that using the FBP reconstructed TCT images resulted in higher count density in the left ventricular (LV) wall of the attenuation compensated SPECT images. The LV wall count density obtained using the iteratively reconstructed TCT images with and without support were similar to each other and were more accurate than that using the FBP. However, the TCT images obtained with support show fewer image artifacts than without support. Among the iterative reconstruction algorithms, the ML-SA algorithm provides the most accurate reconstruction but is the slowest. The BIT algorithm is the fastest but shows the most image artifacts. We conclude that accurate attenuation compensated images can be obtained with truncated 180{degrees} data from large patients using a right-angle dual-camera SPECT system.« less

Design and development of MR-compatible SPECT systems for simultaneous SPECT-MR imaging of small animals

NASA Astrophysics Data System (ADS)

Tsui, Benjamin M. W.; Hugg, James W.; Xu, Jingyan; Chen, Si; Meier, Dirk; Edelstein, William; El-Sharkawy, Abdel; Wagenaar, Douglas J.; Patt, Bradley E.

2011-03-01

We describe a continuing design and development of MR-compatible SPECT systems for simultaneous SPECT-MR imaging of small animals. A first generation prototype SPECT system was designed and constructed to fit inside a MRI system with a gradient bore inner diameter of 12 cm. It consists of 3 angularly offset rings of 8 detectors (1"x1", 16x16 pixels MR-compatible solid-state CZT). A matching 24-pinhole collimator sleeve, made of a tungsten-compound, provides projections from a common FOV of ~25 mm. A birdcage RF coil for MRI data acquisition surrounds the collimator. The SPECT system was tested inside a clinical 3T MRI system. Minimal interference was observed on the simultaneously acquired SPECT and MR images. We developed a sparse-view image reconstruction method based on accurate modeling of the point response function (PRF) of each of the 24 pinholes to provide artifact-free SPECT images. The stationary SPECT system provides relatively low resolution of 3-5 mm but high geometric efficiency of 0.5- 1.2% for fast dynamic acquisition, demonstrated in a SPECT renal kinetics study using Tc-99m DTPA. Based on these results, a second generation prototype MR-compatible SPECT system with an outer diameter of 20 cm that fits inside a mid-sized preclinical MRI system is being developed. It consists of 5 rings of 19 CZT detectors. The larger ring diameter allows the use of optimized multi-pinhole collimator designs, such as high system resolution up to ~1 mm, high geometric efficiency, or lower system resolution without collimator rotation. The anticipated performance of the new system is supported by simulation data.

Morphology supporting function: attenuation correction for SPECT/CT, PET/CT, and PET/MR imaging

PubMed Central

Lee, Tzu C.; Alessio, Adam M.; Miyaoka, Robert M.; Kinahan, Paul E.

2017-01-01

Both SPECT, and in particular PET, are unique in medical imaging for their high sensitivity and direct link to a physical quantity, i.e. radiotracer concentration. This gives PET and SPECT imaging unique capabilities for accurately monitoring disease activity for the purposes of clinical management or therapy development. However, to achieve a direct quantitative connection between the underlying radiotracer concentration and the reconstructed image values several confounding physical effects have to be estimated, notably photon attenuation and scatter. With the advent of dual-modality SPECT/CT, PET/CT, and PET/MR scanners, the complementary CT or MR image data can enable these corrections, although there are unique challenges for each combination. This review covers the basic physics underlying photon attenuation and scatter and summarizes technical considerations for multimodal imaging with regard to PET and SPECT quantification and methods to address the challenges for each multimodal combination. PMID:26576737

Limited angle tomographic breast imaging: A comparison of parallel beam and pinhole collimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wessell, D.E.; Kadrmas, D.J.; Frey, E.C.

1996-12-31

Results from clinical trials have suggested no improvement in lesion detection with parallel hole SPECT scintimammography (SM) with Tc-99m over parallel hole planar SM. In this initial investigation, we have elucidated some of the unique requirements of SPECT SM. With these requirements in mind, we have begun to develop practical data acquisition and reconstruction strategies that can reduce image artifacts and improve image quality. In this paper we investigate limited angle orbits for both parallel hole and pinhole SPECT SM. Singular Value Decomposition (SVD) is used to analyze the artifacts associated with the limited angle orbits. Maximum likelihood expectation maximizationmore » (MLEM) reconstructions are then used to examine the effects of attenuation compensation on the quality of the reconstructed image. All simulations are performed using the 3D-MCAT breast phantom. The results of these simulation studies demonstrate that limited angle SPECT SM is feasible, that attenuation correction is needed for accurate reconstructions, and that pinhole SPECT SM may have an advantage over parallel hole SPECT SM in terms of improved image quality and reduced image artifacts.« less

A one-pot radioiodination of aryl amines via stable diazonium salts: preparation of 125I-imaging agents.

PubMed

Sloan, Nikki L; Luthra, Sajinder K; McRobbie, Graeme; Pimlott, Sally L; Sutherland, Andrew

2017-10-05

An operationally simple, one-pot, two-step tandem procedure that allows the incorporation of radioactive iodine into aryl amines via stable diazonium salts is described. The mild conditions are tolerant of various functional groups and substitution patterns, allowing late-stage, rapid access to a wide range of 125 I-labelled aryl compounds and SPECT radiotracers.

Optimization of SPECT-CT Hybrid Imaging Using Iterative Image Reconstruction for Low-Dose CT: A Phantom Study

PubMed Central

Grosser, Oliver S.; Kupitz, Dennis; Ruf, Juri; Czuczwara, Damian; Steffen, Ingo G.; Furth, Christian; Thormann, Markus; Loewenthal, David; Ricke, Jens; Amthauer, Holger

2015-01-01

Background Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) with computed tomography (CT). Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic applications. It was the aim of this study to investigate the influence of an iterative CT image reconstruction algorithm (ASIR) on the image quality of the low-dose CT images. Methodology/Principal Findings Examinations were performed with a SPECT-CT scanner with standardized CT and SPECT-phantom geometries and CT protocols with systematically reduced X-ray tube currents. Analyses included image quality with respect to photon flux. Results were compared to the standard FBP reconstructed images. The general impact of the CT-based attenuation maps used during SPECT reconstruction was examined for two SPECT phantoms. Using ASIR for image reconstructions, image noise was reduced compared to FBP reconstructions for the same X-ray tube current. The Hounsfield unit (HU) values reconstructed by ASIR were correlated to the FBP HU values(R2 ≥ 0.88) and the contrast-to-noise ratio (CNR) was improved by ASIR. However, for a phantom with increased attenuation, the HU values shifted for low X-ray tube currents I ≤ 60 mA (p ≤ 0.04). In addition, the shift of the HU values was observed within the attenuation corrected SPECT images for very low X-ray tube currents (I ≤ 20 mA, p ≤ 0.001). Conclusion/Significance In general, the decrease in X-ray tube current up to 30 mA in combination with ASIR led to a reduction of CT-related radiation exposure without a significant decrease in image quality. PMID:26390216

Coregistration of Magnetic Resonance and Single Photon Emission Computed Tomography Images for Noninvasive Localization of Stem Cells Grafted in the Infarcted Rat Myocardium

PubMed Central

Shen, Dinggang; Liu, Dengfeng; Cao, Zixiong; Acton, Paul D.; Zhou, Rong

2008-01-01

This paper demonstrates the application of mutual information based coregistration of radionuclide and magnetic resonance imaging (MRI) in an effort to use multimodality imaging for noninvasive localization of stem cells grafted in the infarcted myocardium in rats. Radionuclide imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) inherently has high sensitivity and is suitable for tracking of labeled stem cells, while high-resolution MRI is able to provide detailed anatomical and functional information of myocardium. Thus, coregistration of PET or SPECT images with MRI will map the location and distribution of stem cells on detailed myocardium structures. To validate this coregistration method, SPECT data were simulated by using a Monte Carlo-based projector that modeled the pinhole-imaging physics assuming nonzero diameter and photon penetration at the edge. Translational and rotational errors of the coregistration were examined with respect to various SPECT activities, and they are on average about 0.50 mm and 0.82°, respectively. Only the rotational error is dependent on activity of SPECT data. Stem cells were labeled with 111 Indium oxyquinoline and grafted in the ischemic myocardium of a rat model. Dual-tracer small-animal SPECT images were acquired, which allowed simultaneous detection of 111In-labeled stem cells and of [99mTc]sestamibi to assess myocardial perfusion deficit. The same animals were subjected to cardiac MRI. A mutual-information-based coregistration method was then applied to the SPECT and MRIs. By coregistration, the 111 In signal from labeled cells was mapped into the akinetic region identified on cine MRIs; the regional perfusion deficit on the SPECT images also coincided with the akinetic region on the MR image. PMID:17053860

SPECT reconstruction with nonuniform attenuation from highly under-sampled projection data

NASA Astrophysics Data System (ADS)

Li, Cuifen; Wen, Junhai; Zhang, Kangping; Shi, Donghao; Dong, Haixiang; Li, Wenxiao; Liang, Zhengrong

2012-03-01

Single photon emission computed tomography (SPECT) is an important nuclear medicine imaging technique and has been using in clinical diagnoses. The SPECT image can reflect not only organizational structure but also functional activities of human body, therefore diseases can be found much earlier. In SPECT, the reconstruction is based on the measurement of gamma photons emitted by the radiotracer. The number of gamma photons detected is proportional to the dose of radiopharmaceutical, but the dose is limited because of patient safety. There is an upper limit in the number of gamma photons that can be detected per unit time, so it takes a long time to acquire SPECT projection data. Sometimes we just can obtain highly under-sampled projection data because of the limit of the scanning time or imaging hardware. How to reconstruct an image using highly under-sampled projection data is an interesting problem. One method is to minimize the total variation (TV) of the reconstructed image during the iterative reconstruction. In this work, we developed an OSEM-TV SPECT reconstruction algorithm, which could reconstruct the image from highly under-sampled projection data with non-uniform attenuation. Simulation results demonstrate that the OSEM-TV algorithm performs well in SPECT reconstruction with non-uniform attenuation.

Fabrication of the pinhole aperture for AdaptiSPECT

PubMed Central

Kovalsky, Stephen; Kupinski, Matthew A.; Barrett, Harrison H.; Furenlid, Lars R.

2015-01-01

AdaptiSPECT is a pre-clinical pinhole SPECT imaging system under final construction at the Center for Gamma-Ray Imaging. The system is designed to be able to autonomously change its imaging configuration. The system comprises 16 detectors mounted on translational stages to move radially away and towards the center of the field-of-view. The system also possesses an adaptive pinhole aperture with multiple collimator diameters and pinhole sizes, as well as the possibility to switch between multiplexed and non-multiplexed imaging configurations. In this paper, we describe the fabrication of the AdaptiSPECT pinhole aperture and its controllers. PMID:26146443

Pulmonary Ventilation Imaging Based on 4-Dimensional Computed Tomography: Comparison With Pulmonary Function Tests and SPECT Ventilation Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamamoto, Tokihiro, E-mail: toyamamoto@ucdavis.edu; Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, California; Kabus, Sven

Purpose: 4-dimensional computed tomography (4D-CT)-based pulmonary ventilation imaging is an emerging functional imaging modality. The purpose of this study was to investigate the physiological significance of 4D-CT ventilation imaging by comparison with pulmonary function test (PFT) measurements and single-photon emission CT (SPECT) ventilation images, which are the clinical references for global and regional lung function, respectively. Methods and Materials: In an institutional review board–approved prospective clinical trial, 4D-CT imaging and PFT and/or SPECT ventilation imaging were performed in thoracic cancer patients. Regional ventilation (V{sub 4DCT}) was calculated by deformable image registration of 4D-CT images and quantitative analysis for regional volumemore » change. V{sub 4DCT} defect parameters were compared with the PFT measurements (forced expiratory volume in 1 second (FEV{sub 1}; % predicted) and FEV{sub 1}/forced vital capacity (FVC; %). V{sub 4DCT} was also compared with SPECT ventilation (V{sub SPECT}) to (1) test whether V{sub 4DCT} in V{sub SPECT} defect regions is significantly lower than in nondefect regions by using the 2-tailed t test; (2) to quantify the spatial overlap between V{sub 4DCT} and V{sub SPECT} defect regions with Dice similarity coefficient (DSC); and (3) to test ventral-to-dorsal gradients by using the 2-tailed t test. Results: Of 21 patients enrolled in the study, 18 patients for whom 4D-CT and either PFT or SPECT were acquired were included in the analysis. V{sub 4DCT} defect parameters were found to have significant, moderate correlations with PFT measurements. For example, V{sub 4DCT}{sup HU} defect volume increased significantly with decreasing FEV{sub 1}/FVC (R=−0.65, P<.01). V{sub 4DCT} in V{sub SPECT} defect regions was significantly lower than in nondefect regions (mean V{sub 4DCT}{sup HU} 0.049 vs 0.076, P<.01). The average DSCs for the spatial overlap with SPECT ventilation defect regions were only moderate (V{sub 4DCT}{sup HU}0.39 ± 0.11). Furthermore, ventral-to-dorsal gradients of V{sub 4DCT} were strong (V{sub 4DCT}{sup HU} R{sup 2} = 0.69, P=.08), which was similar to V{sub SPECT} (R{sup 2} = 0.96, P<.01). Conclusions: An 18-patient study demonstrated significant correlations between 4D-CT ventilation and PFT measurements as well as SPECT ventilation, providing evidence toward the validation of 4D-CT ventilation imaging.« less

TU-A-12A-02: Novel Lung Ventilation Imaging with Single Energy CT After Single Inhalation of Xenon: Comparison with SPECT Ventilation Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negahdar, M; Yamamoto, T; Shultz, D

Purpose: We propose a novel lung functional imaging method to determine the spatial distribution of xenon (Xe) gas in a single inhalation as a measure of regional ventilation. We compare Xe-CT ventilation to single-photon emission CT (SPECT) ventilation, which is the current clinical reference. Regional lung ventilation information may be useful for the diagnosis and monitoring of pulmonary diseases such as COPD, radiotherapy planning, and assessing the progression of toxicity after radiation therapy. Methods: In an IRB-approved clinical study, Xe-CT and SPECT ventilation scans were acquired for three patients including one patient with severe emphysema and two lung cancer patientsmore » treated with radiotherapy. For Xe- CT, we acquired two breath-hold single energy CT images of the entire lung with inspiration of 100% O2 and a mixture of 70% Xe and 30% O2, respectively. A video biofeedback system was used to achieve reproducible breath-holds. We used deformable image registration to align the breathhold images with each other to accurately subtract them, producing a map of the distribution of Xe as a surrogate of lung ventilation. We divided each lung into twelve parts and correlated the Hounsfield unit (HU) enhancement at each part with the SPECT ventilation count of the corresponding part of the lung. Results: The mean of the Pearson linear correlation coefficient values between the Xe-CT and ventilation SPECT count for all three patients were 0.62 (p<0.01). The Xe-CT image had a higher resolution than SPECT, and did not show central airway deposition artifacts that were present in the SPECT image. Conclusion: We developed a rapid, safe, clinically practical, and potentially widely accessible method for regional lung functional imaging. We demonstrated strong correlations between the Xe-CT ventilation image and SPECT ventilation image as the clinical reference. This ongoing study will investigate more patients to confirm this finding.« less

Initial Investigation of preclinical integrated SPECT and MR imaging.

PubMed

Hamamura, Mark J; Ha, Seunghoon; Roeck, Werner W; Wagenaar, Douglas J; Meier, Dirk; Patt, Bradley E; Nalcioglu, Orhan

2010-02-01

Single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high-spatial resolution anatomical information as well as complementary functional information. In this study, we utilized a dual modality SPECT/MRI (MRSPECT) system to investigate the integration of SPECT and MRI for improved image accuracy. The MRSPECT system consisted of a cadmium-zinc-telluride (CZT) nuclear radiation detector interfaced with a specialized radiofrequency (RF) coil that was placed within a whole-body 4 T MRI system. The importance of proper corrections for non-uniform detector sensitivity and Lorentz force effects was demonstrated. MRI data were utilized for attenuation correction (AC) of the nuclear projection data and optimized Wiener filtering of the SPECT reconstruction for improved image accuracy. Finally, simultaneous dual-imaging of a nude mouse was performed to demonstrated the utility of co-registration for accurate localization of a radioactive source.

Initial Investigation of Preclinical Integrated SPECT and MR Imaging

PubMed Central

Hamamura, Mark J.; Ha, Seunghoon; Roeck, Werner W.; Wagenaar, Douglas J.; Meier, Dirk; Patt, Bradley E.; Nalcioglu, Orhan

2014-01-01

Single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high-spatial resolution anatomical information as well as complementary functional information. In this study, we utilized a dual modality SPECT/MRI (MRSPECT) system to investigate the integration of SPECT and MRI for improved image accuracy. The MRSPECT system consisted of a cadmium-zinc-telluride (CZT) nuclear radiation detector interfaced with a specialized radiofrequency (RF) coil that was placed within a whole-body 4 T MRI system. The importance of proper corrections for non-uniform detector sensitivity and Lorentz force effects was demonstrated. MRI data were utilized for attenuation correction (AC) of the nuclear projection data and optimized Wiener filtering of the SPECT reconstruction for improved image accuracy. Finally, simultaneous dual-imaging of a nude mouse was performed to demonstrated the utility of co-registration for accurate localization of a radioactive source. PMID:20082527

A methodology for generating normal and pathological brain perfusion SPECT images for evaluation of MRI/SPECT fusion methods: application in epilepsy

NASA Astrophysics Data System (ADS)

Grova, C.; Jannin, P.; Biraben, A.; Buvat, I.; Benali, H.; Bernard, A. M.; Scarabin, J. M.; Gibaud, B.

2003-12-01

Quantitative evaluation of brain MRI/SPECT fusion methods for normal and in particular pathological datasets is difficult, due to the frequent lack of relevant ground truth. We propose a methodology to generate MRI and SPECT datasets dedicated to the evaluation of MRI/SPECT fusion methods and illustrate the method when dealing with ictal SPECT. The method consists in generating normal or pathological SPECT data perfectly aligned with a high-resolution 3D T1-weighted MRI using realistic Monte Carlo simulations that closely reproduce the response of a SPECT imaging system. Anatomical input data for the SPECT simulations are obtained from this 3D T1-weighted MRI, while functional input data result from an inter-individual analysis of anatomically standardized SPECT data. The method makes it possible to control the 'brain perfusion' function by proposing a theoretical model of brain perfusion from measurements performed on real SPECT images. Our method provides an absolute gold standard for assessing MRI/SPECT registration method accuracy since, by construction, the SPECT data are perfectly registered with the MRI data. The proposed methodology has been applied to create a theoretical model of normal brain perfusion and ictal brain perfusion characteristic of mesial temporal lobe epilepsy. To approach realistic and unbiased perfusion models, real SPECT data were corrected for uniform attenuation, scatter and partial volume effect. An anatomic standardization was used to account for anatomic variability between subjects. Realistic simulations of normal and ictal SPECT deduced from these perfusion models are presented. The comparison of real and simulated SPECT images showed relative differences in regional activity concentration of less than 20% in most anatomical structures, for both normal and ictal data, suggesting realistic models of perfusion distributions for evaluation purposes. Inter-hemispheric asymmetry coefficients measured on simulated data were found within the range of asymmetry coefficients measured on corresponding real data. The features of the proposed approach are compared with those of other methods previously described to obtain datasets appropriate for the assessment of fusion methods.

Clinical application of 3D arterial spin-labeled brain perfusion imaging for Alzheimer disease: comparison with brain perfusion SPECT.

PubMed

Takahashi, H; Ishii, K; Hosokawa, C; Hyodo, T; Kashiwagi, N; Matsuki, M; Ashikaga, R; Murakami, T

2014-05-01

Alzheimer disease is the most common neurodegenerative disorder with dementia, and a practical and economic biomarker for diagnosis of Alzheimer disease is needed. Three-dimensional arterial spin-labeling, with its high signal-to-noise ratio, enables measurement of cerebral blood flow precisely without any extrinsic tracers. We evaluated the performance of 3D arterial spin-labeling compared with SPECT, and demonstrated the 3D arterial spin-labeled imaging characteristics in the diagnosis of Alzheimer disease. This study included 68 patients with clinically suspected Alzheimer disease who underwent both 3D arterial spin-labeling and SPECT imaging. Two readers independently assessed both images. Kendall W coefficients of concordance (K) were computed, and receiver operating characteristic analyses were performed for each reader. The differences between the images in regional perfusion distribution were evaluated by means of statistical parametric mapping, and the incidence of hypoperfusion of the cerebral watershed area, referred to as "borderzone sign" in the 3D arterial spin-labeled images, was determined. Readers showed K = 0.82/0.73 for SPECT/3D arterial spin-labeled imaging, and the respective areas under the receiver operating characteristic curve were 0.82/0.69 for reader 1 and 0.80/0.69 for reader 2. Statistical parametric mapping showed that the perisylvian and medial parieto-occipital perfusion in the arterial spin-labeled images was significantly higher than that in the SPECT images. Borderzone sign was observed on 3D arterial spin-labeling in 70% of patients misdiagnosed with Alzheimer disease. The diagnostic performance of 3D arterial spin-labeling and SPECT for Alzheimer disease was almost equivalent. Three-dimensional arterial spin-labeled imaging was more influenced by hemodynamic factors than was SPECT imaging. © 2014 by American Journal of Neuroradiology.

Design and evaluation of corn starch-bonded Rhizophora spp. particleboard phantoms for SPECT/CT imaging

NASA Astrophysics Data System (ADS)

Hamid, Puteri Nor Khatijah Abd; Yusof, Mohd Fahmi Mohd; Aziz Tajuddin, Abd; Hashim, Rokiah; Zainon, Rafidah

2018-01-01

The aim of this study was to design and evaluate of corn starch-bonded Rhizophora spp. particleboards as phantom for SPECT/CT imaging. The phantom was designed according to the Jaszczak phantom commonly used in SPECT imaging with dimension of 22 cm diameter and 18 cm length. Six inserts with different diameter were made for insertion of vials filled with 1.6 µCi/ml of 99mTc unsealed source. The particleboard phantom was scanned using SPECT/CT imaging protocol. The contrast of each vial for particleboards phantom were calculated based on the ratio of counts in radionuclide volume and phantom background and compared to Perspex® and water phantom. The results showed that contrast values for each vial in particleboard phantomis near to 1.0 and in good agreement with Perspex® and water phantoms as common phantom materials for SPECT/CT. The paired sample t-test result showed no significant difference of contrast values between images in particleboard phantoms and that in water. The overall results showed the potential of corn starch-bonded Rhizophora spp. as phantom for quality control and dosimetry works in SPECT/CT imaging.

Navigation of a robot-integrated fluorescence laparoscope in preoperative SPECT/CT and intraoperative freehand SPECT imaging data: a phantom study

NASA Astrophysics Data System (ADS)

van Oosterom, Matthias Nathanaël; Engelen, Myrthe Adriana; van den Berg, Nynke Sjoerdtje; KleinJan, Gijs Hendrik; van der Poel, Henk Gerrit; Wendler, Thomas; van de Velde, Cornelis Jan Hadde; Navab, Nassir; van Leeuwen, Fijs Willem Bernhard

2016-08-01

Robot-assisted laparoscopic surgery is becoming an established technique for prostatectomy and is increasingly being explored for other types of cancer. Linking intraoperative imaging techniques, such as fluorescence guidance, with the three-dimensional insights provided by preoperative imaging remains a challenge. Navigation technologies may provide a solution, especially when directly linked to both the robotic setup and the fluorescence laparoscope. We evaluated the feasibility of such a setup. Preoperative single-photon emission computed tomography/X-ray computed tomography (SPECT/CT) or intraoperative freehand SPECT (fhSPECT) scans were used to navigate an optically tracked robot-integrated fluorescence laparoscope via an augmented reality overlay in the laparoscopic video feed. The navigation accuracy was evaluated in soft tissue phantoms, followed by studies in a human-like torso phantom. Navigation accuracies found for SPECT/CT-based navigation were 2.25 mm (coronal) and 2.08 mm (sagittal). For fhSPECT-based navigation, these were 1.92 mm (coronal) and 2.83 mm (sagittal). All errors remained below the <1-cm detection limit for fluorescence imaging, allowing refinement of the navigation process using fluorescence findings. The phantom experiments performed suggest that SPECT-based navigation of the robot-integrated fluorescence laparoscope is feasible and may aid fluorescence-guided surgery procedures.

Performance evaluation of a compact PET/SPECT/CT tri-modality system for small animal imaging applications

NASA Astrophysics Data System (ADS)

Wei, Qingyang; Wang, Shi; Ma, Tianyu; Wu, Jing; Liu, Hui; Xu, Tianpeng; Xia, Yan; Fan, Peng; Lyu, Zhenlei; Liu, Yaqiang

2015-06-01

PET, SPECT and CT imaging techniques are widely used in preclinical small animal imaging applications. In this paper, we present a compact small animal PET/SPECT/CT tri-modality system. A dual-functional, shared detector design is implemented which enables PET and SPECT imaging with a same LYSO ring detector. A multi-pinhole collimator is mounted on the system and inserted into the detector ring in SPECT imaging mode. A cone-beam CT consisting of a micro focus X-ray tube and a CMOS detector is implemented. The detailed design and the performance evaluations are reported in this paper. In PET imaging mode, the measured NEMA based spatial resolution is 2.12 mm (FWHM), and the sensitivity at the central field of view (CFOV) is 3.2%. The FOV size is 50 mm (∅)×100 mm (L). The SPECT has a spatial resolution of 1.32 mm (FWHM) and an average sensitivity of 0.031% at the center axial, and a 30 mm (∅)×90 mm (L) FOV. The CT spatial resolution is 8.32 lp/mm @10%MTF, and the contrast discrimination function value is 2.06% with 1.5 mm size cubic box object. In conclusion, a compact, tri-modality PET/SPECT/CT system was successfully built with low cost and high performance.

Comparison of SPECT/CT, MRI and CT in diagnosis of skull base bone invasion in nasopharyngeal carcinoma.

PubMed

Zhang, Shu-xu; Han, Peng-hui; Zhang, Guo-qian; Wang, Rui-hao; Ge, Yong-bin; Ren, Zhi-gang; Li, Jian-sheng; Fu, Wen-hai

2014-01-01

Early detection of skull base invasion in nasopharyngeal carcinoma (NPC) is crucial for correct staging, assessing treatment response and contouring the tumor target in radiotherapy planning, as well as improving the patient's prognosis. To compare the diagnostic efficacy of single photon emission computed tomography/computed tomography (SPECT/CT) imaging, magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of skull base invasion in NPC. Sixty untreated patients with histologically proven NPC underwent SPECT/CT imaging, contrast-enhanced MRI and CT. Of the 60 patients, 30 had skull base invasion confirmed by the final results of contrast-enhanced MRI, CT and six-month follow-up imaging (MRI and CT). The diagnostic efficacy of the three imaging modalities in detecting skull base invasion was evaluated. The rates of positive findings of skull base invasion for SPECT/CT, MRI and CT were 53.3%, 48.3% and 33.3%, respectively. The sensitivity, specificity and accuracy were 93.3%, 86.7% and 90.0% for SPECT/CT fusion imaging, 96.7%, 100.0% and 98.3% for contrast-enhanced MRI, and 66.7%, 100.0% and 83.3% for contrast-enhanced CT. MRI showed the best performance for the diagnosis of skull base invasion in nasopharyngeal carcinoma, followed closely by SPECT/CT. SPECT/CT had poorer specificity than that of both MRI and CT, while CT had the lowest sensitivity.

Pre-clinical and Clinical Evaluation of High Resolution, Mobile Gamma Camera and Positron Imaging Devices

DTIC Science & Technology

2009-10-01

Field-of-View, Mobile PET/SPECT System for Bedside Environments: A Dynamic Cardiac Phantom Study using 99mTc and 18F- FDG . Presented at the American...using Tc-99m tracers and viability imaging using F- 18 tracers [3]-[7]. For cardiac F-18 imaging in a bedside environment, the 511 keV SPECT approach...SPECT system may have difficulty imaging subtle myocardial defects with F-18 tracers , but it may effectively image moderate to severe defects. The

Effects of Glycosylation on Biodistribution and Imaging Quality of Necrotic Myocardium of Iodine-131-Labeled Sennidins.

PubMed

Li, Ling; Zhang, Dongjian; Yang, Shengwei; Song, Shaoli; Li, Jindian; Wang, Qin; Wang, Cong; Feng, Yuanbo; Ni, Yicheng; Zhang, Jian; Liu, Wei; Yin, Zhiqi

2016-12-01

Sennidins are necrosis-avid agents for noninvasive assessment of myocardial viability which is important for patients with myocardial infarction (MI). However, high accumulation of radioactivity in the liver interferes with the assessment of myocardial viability. In this study, we compared sennidins with sennosides to investigate the effects of glycosylation on biodistribution and imaging quality of sennidins. Sennidin A (SA), sennidin B (SB), sennoside A (SSA), and sennoside B (SSB) were labeled with I-131. In vitro binding to necrotic cells and hepatic cells and in vivo biodistribution in rats with muscular necrosis were evaluated by gamma counting, autoradiography, and histopathology. Single photon emission computed tomography/computed tomography (SPECT/CT) images were acquired in rats with acute MI. The uptake of [ 131 I]SA, [ 131 I]SSA, [ 131 I]SB, and [ 131 I]SSB in necrotic cells was significantly higher than that in viable cells (p < 0.05). Hepatic cells uptake of [ 131 I]SSA and [ 131 I]SSB were 7-fold and 10-fold lower than that of corresponding [ 131 I]SA and [ 131 I]SB, respectively. The biodistribution data showed that the radioactivities in the liver and feces were significantly lower with [ 131 I]sennosides than those with [ 131 I]sennidins (p < 0.01). Autoradiography showed preferential accumulation of these four radiotracers in necrotic areas of muscle, confirmed by histopathology. SPECT/CT imaging studies showed better image quality with [ 131 I]SSB than with [ 131 I]SB due to less liver interference. Glycosylation significantly decreased the liver uptake and improved the quality of cardiac imaging. [ 131 I]SSB may serve as a promising necrosis-avid agent for noninvasive assessment of myocardial viability.

Voxel-based correlation between coregistered single-photon emission computed tomography and dynamic susceptibility contrast magnetic resonance imaging in subjects with suspected Alzheimer disease.

PubMed

Cavallin, L; Axelsson, R; Wahlund, L O; Oksengard, A R; Svensson, L; Juhlin, P; Wiberg, M Kristoffersen; Frank, A

2008-12-01

Current diagnosis of Alzheimer disease is made by clinical, neuropsychologic, and neuroimaging assessments. Neuroimaging techniques such as magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) could be valuable in the differential diagnosis of Alzheimer disease, as well as in assessing prognosis. To compare SPECT and MRI in a cohort of patients examined for suspected dementia, including patients with no objective cognitive impairment (control group), mild cognitive impairment (MCI), and Alzheimer disease (AD). 24 patients, eight with AD, 10 with MCI, and six controls, were investigated with SPECT using (99m)Tc-hexamethylpropyleneamine oxime (HMPAO, Ceretec; GE Healthcare Ltd., Little Chalsont UK) and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with a contrast-enhancing gadobutrol formula (Gadovist; Bayer Schering Pharma, Berlin, Germany). Voxel-based correlation between coregistered SPECT and DSC-MR images was calculated. Region-of-interest (ROI) analyses were then performed in 24 different brain areas using brain registration and analysis of SPECT studies (BRASS; Nuclear Diagnostics AB, Stockholm, Sweden) on both SPECT and DSC-MRI. Voxel-based correlation between coregistered SPECT and DSC-MR showed a high correlation, with a mean correlation coefficient of 0.94. ROI analyses of 24 regions showed significant differences between the control group and AD patients in 10 regions using SPECT and five regions in DSC-MR. SPECT remains superior to DSC-MRI in differentiating normal from pathological perfusion, and DSC-MRI could not replace SPECT in the diagnosis of patients with Alzheimer disease.

Development of an MR-compatible SPECT system (MRSPECT) for simultaneous data acquisition.

PubMed

Hamamura, Mark J; Ha, Seunghoon; Roeck, Werner W; Muftuler, L Tugan; Wagenaar, Douglas J; Meier, Dirk; Patt, Bradley E; Nalcioglu, Orhan

2010-03-21

In medical imaging, single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high spatial resolution anatomical information as well as complementary functional information. In this study, we developed a miniaturized dual-modality SPECT/MRI (MRSPECT) system and demonstrated the feasibility of simultaneous SPECT and MRI data acquisition, with the possibility of whole-body MRSPECT systems through suitable scaling of components. For our MRSPECT system, a cadmium-zinc-telluride (CZT) nuclear radiation detector was interfaced with a specialized radiofrequency (RF) coil and placed within a whole-body 4 T MRI system. Various phantom experiments characterized the interaction between the SPECT and MRI hardware components. The metallic components of the SPECT hardware altered the B(0) field and generated a non-uniform reduction in the signal-to-noise ratio (SNR) of the MR images. The presence of a magnetic field generated a position shift and resolution loss in the nuclear projection data. Various techniques were proposed to compensate for these adverse effects. Overall, our results demonstrate that accurate, simultaneous SPECT and MRI data acquisition is feasible, justifying the further development of MRSPECT for either small-animal imaging or whole-body human systems by using appropriate components.

Development of an MR-compatible SPECT system (MRSPECT) for simultaneous data acquisition

NASA Astrophysics Data System (ADS)

Hamamura, Mark J.; Ha, Seunghoon; Roeck, Werner W.; Tugan Muftuler, L.; Wagenaar, Douglas J.; Meier, Dirk; Patt, Bradley E.; Nalcioglu, Orhan

2010-03-01

In medical imaging, single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high spatial resolution anatomical information as well as complementary functional information. In this study, we developed a miniaturized dual-modality SPECT/MRI (MRSPECT) system and demonstrated the feasibility of simultaneous SPECT and MRI data acquisition, with the possibility of whole-body MRSPECT systems through suitable scaling of components. For our MRSPECT system, a cadmium-zinc-telluride (CZT) nuclear radiation detector was interfaced with a specialized radiofrequency (RF) coil and placed within a whole-body 4 T MRI system. Various phantom experiments characterized the interaction between the SPECT and MRI hardware components. The metallic components of the SPECT hardware altered the B0 field and generated a non-uniform reduction in the signal-to-noise ratio (SNR) of the MR images. The presence of a magnetic field generated a position shift and resolution loss in the nuclear projection data. Various techniques were proposed to compensate for these adverse effects. Overall, our results demonstrate that accurate, simultaneous SPECT and MRI data acquisition is feasible, justifying the further development of MRSPECT for either small-animal imaging or whole-body human systems by using appropriate components.

Forensic applications of cerebral single photon emission computed tomography in mild traumatic brain injury.

PubMed

Wortzel, Hal S; Filley, Christopher M; Anderson, C Alan; Oster, Timothy; Arciniegas, David B

2008-01-01

Traumatic brain injury (TBI) is a substantial source of mortality and morbidity world wide. Although most such injuries are relatively mild, accurate diagnosis and prognostication after mild TBI are challenging. These problems are complicated further when considered in medicolegal contexts, particularly civil litigation. Cerebral single photon emission computed tomography (SPECT) may contribute to the evaluation and treatment of persons with mild TBI. Cerebral SPECT is relatively sensitive to the metabolic changes produced by TBI. However, such changes are not specific to this condition, and their presence on cerebral SPECT imaging does not confirm a diagnosis of mild TBI. Conversely, the absence of abnormalities on cerebral SPECT imaging does not exclude a diagnosis of mild TBI, although such findings may be of prognostic value. The literature does not demonstrate consistent relationships between SPECT images and neuropsychological testing or neuropsychiatric symptoms. Using the rules of evidence shaped by Daubert v. Merrell Dow Pharmaceuticals, Inc., and its progeny to analyze the suitability of SPECT for forensic purposes, we suggest that expert testimony regarding SPECT findings should be admissible only as evidence to support clinical history, neuropsychological test results, and structural brain imaging findings and not as stand-alone diagnostic data.

A hardware investigation of robotic SPECT for functional and molecular imaging onboard radiation therapy systems

PubMed Central

Yan, Susu; Bowsher, James; Tough, MengHeng; Cheng, Lin; Yin, Fang-Fang

2014-01-01

Purpose: To construct a robotic SPECT system and to demonstrate its capability to image a thorax phantom on a radiation therapy flat-top couch, as a step toward onboard functional and molecular imaging in radiation therapy. Methods: A robotic SPECT imaging system was constructed utilizing a gamma camera detector (Digirad 2020tc) and a robot (KUKA KR150 L110 robot). An imaging study was performed with a phantom (PET CT PhantomTM), which includes five spheres of 10, 13, 17, 22, and 28 mm diameters. The phantom was placed on a flat-top couch. SPECT projections were acquired either with a parallel-hole collimator or a single-pinhole collimator, both without background in the phantom and with background at 1/10th the sphere activity concentration. The imaging trajectories of parallel-hole and pinhole collimated detectors spanned 180° and 228°, respectively. The pinhole detector viewed an off-centered spherical common volume which encompassed the 28 and 22 mm spheres. The common volume for parallel-hole system was centered at the phantom which encompassed all five spheres in the phantom. The maneuverability of the robotic system was tested by navigating the detector to trace the phantom and flat-top table while avoiding collision and maintaining the closest possible proximity to the common volume. The robot base and tool coordinates were used for image reconstruction. Results: The robotic SPECT system was able to maneuver parallel-hole and pinhole collimated SPECT detectors in close proximity to the phantom, minimizing impact of the flat-top couch on detector radius of rotation. Without background, all five spheres were visible in the reconstructed parallel-hole image, while four spheres, all except the smallest one, were visible in the reconstructed pinhole image. With background, three spheres of 17, 22, and 28 mm diameters were readily observed with the parallel-hole imaging, and the targeted spheres (22 and 28 mm diameters) were readily observed in the pinhole region-of-interest imaging. Conclusions: Onboard SPECT could be achieved by a robot maneuvering a SPECT detector about patients in position for radiation therapy on a flat-top couch. The robot inherent coordinate frames could be an effective means to estimate detector pose for use in SPECT image reconstruction. PMID:25370663

A hardware investigation of robotic SPECT for functional and molecular imaging onboard radiation therapy systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Susu, E-mail: susu.yan@duke.edu; Tough, MengHeng; Bowsher, James

Purpose: To construct a robotic SPECT system and to demonstrate its capability to image a thorax phantom on a radiation therapy flat-top couch, as a step toward onboard functional and molecular imaging in radiation therapy. Methods: A robotic SPECT imaging system was constructed utilizing a gamma camera detector (Digirad 2020tc) and a robot (KUKA KR150 L110 robot). An imaging study was performed with a phantom (PET CT Phantom{sup TM}), which includes five spheres of 10, 13, 17, 22, and 28 mm diameters. The phantom was placed on a flat-top couch. SPECT projections were acquired either with a parallel-hole collimator ormore » a single-pinhole collimator, both without background in the phantom and with background at 1/10th the sphere activity concentration. The imaging trajectories of parallel-hole and pinhole collimated detectors spanned 180° and 228°, respectively. The pinhole detector viewed an off-centered spherical common volume which encompassed the 28 and 22 mm spheres. The common volume for parallel-hole system was centered at the phantom which encompassed all five spheres in the phantom. The maneuverability of the robotic system was tested by navigating the detector to trace the phantom and flat-top table while avoiding collision and maintaining the closest possible proximity to the common volume. The robot base and tool coordinates were used for image reconstruction. Results: The robotic SPECT system was able to maneuver parallel-hole and pinhole collimated SPECT detectors in close proximity to the phantom, minimizing impact of the flat-top couch on detector radius of rotation. Without background, all five spheres were visible in the reconstructed parallel-hole image, while four spheres, all except the smallest one, were visible in the reconstructed pinhole image. With background, three spheres of 17, 22, and 28 mm diameters were readily observed with the parallel-hole imaging, and the targeted spheres (22 and 28 mm diameters) were readily observed in the pinhole region-of-interest imaging. Conclusions: Onboard SPECT could be achieved by a robot maneuvering a SPECT detector about patients in position for radiation therapy on a flat-top couch. The robot inherent coordinate frames could be an effective means to estimate detector pose for use in SPECT image reconstruction.« less

TH-C-17A-06: A Hardware Implementation and Evaluation of Robotic SPECT: Toward Molecular Imaging Onboard Radiation Therapy Machines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, S; Touch, M; Bowsher, J

Purpose: To construct a robotic SPECT system and demonstrate its capability to image a thorax phantom on a radiation therapy flat-top couch. The system has potential for on-board functional and molecular imaging in radiation therapy. Methods: A robotic SPECT imaging system was developed utilizing a Digirad 2020tc detector and a KUKA KR150-L110 robot. An imaging study was performed with the PET CT Phantom, which includes 5 spheres: 10, 13, 17, 22 and 28 mm in diameter. Sphere-tobackground concentration ratio was 6:1 of Tc99m. The phantom was placed on a flat-top couch. SPECT projections were acquired with a parallel-hole collimator andmore » a single pinhole collimator. The robotic system navigated the detector tracing the flat-top table to maintain the closest possible proximity to the phantom. For image reconstruction, detector trajectories were described by six parameters: radius-of-rotation, x and z detector shifts, and detector rotation θ, tilt ϕ and twist γ. These six parameters were obtained from the robotic system by calibrating the robot base and tool coordinates. Results: The robotic SPECT system was able to maneuver parallel-hole and pinhole collimated SPECT detectors in close proximity to the phantom, minimizing impact of the flat-top couch on detector-to-COR (center-ofrotation) distance. In acquisitions with background at 1/6th sphere activity concentration, photopeak contamination was heavy, yet the 17, 22, and 28 mm diameter spheres were readily observed with the parallel hole imaging, and the single, targeted sphere (28 mm diameter) was readily observed in the pinhole region-of-interest (ROI) imaging. Conclusion: Onboard SPECT could be achieved by a robot maneuvering a SPECT detector about patients in position for radiation therapy on a flat-top couch. The robot inherent coordinate frame could be an effective means to estimate detector pose for use in SPECT image reconstruction. PHS/NIH/NCI grant R21-CA156390-01A1.« less

Molecular Imaging of Conscious, Unrestrained Mice with AwakeSPECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baba, Justin S; Endres, Christopher; Foss, Catherine

2013-01-01

We have developed a SPECT imaging system, AwakeSPECT, to enable molecular brain imaging of untrained mice that are conscious, unanesthetized, and unrestrained. We accomplished this with head tracking and motion correction techniques. Methods: The capability of the system for motion-corrected imaging was demonstrated with a 99mTc-pertechnetate phantom, 99mTcmethylene diphosphonate bone imaging, and measurement of the binding potential of the dopamine transporter radioligand 123I-ioflupane in mouse brain in the awake and anesthetized (isoflurane) states. Stress induced by imaging in the awake state was assessed through measurement of plasma corticosterone levels. Results: AwakeSPECT provided high-resolution bone images reminiscent of those obtained frommore » CT. The binding potential of 123I-ioflupane in the awake state was on the order of 50% of that obtained with the animal under anesthesia, consistent with previous studies in nonhuman primates. Levels of stress induced were on the order of those seen in other behavioral tasks and imaging studies of awake animals. Conclusion: These results demonstrate the feasibility of SPECT molecular brain imaging of mice in the conscious, unrestrained state and demonstrate the effects of isoflurane anesthesia on radiotracer uptake.« less

Molecular Imaging of Conscious, Unrestrained Mice with AwakeSPECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baba, Justin S.; Endres, Christopher J.; Foss, Catherine A.

2013-06-01

We have developed a SPECT imaging system, AwakeSPECT, to enable molecular brain imaging of untrained mice that are conscious, unanesthetized, and unrestrained. We accomplished this with head tracking and motion correction techniques. Methods: The capability of the system for motion-corrected imaging was demonstrated with a ^99mTc-pertechnetate phantom, ^99mTc-methylene diphosphonate bone imaging, and measurement of the binding potential of the dopamine transporter radioligand ^123I-ioflupane in mouse brain in the awake and anesthetized (isoflurane) states. Stress induced by imaging in the awake state was assessed through measurement of plasma corticosterone levels. Results: AwakeSPECT provided high-resolution bone images reminiscent of those obtained frommore » CT. The binding potential of ^123I-ioflupane in the awake state was on the order of 50% of that obtained with the animal under anesthesia, consistent with previous studies in nonhuman primates. Levels of stress induced were on the order of those seen in other behavioral tasks and imaging studies of awake animals. Conclusion: These results demonstrate the feasibility of SPECT molecular brain imaging of mice in the conscious, unrestrained state and demonstrate the effects of isoflurane anesthesia on radiotracer uptake.« less

The Use of Quantitative SPECT/CT Imaging to Assess Residual Limb Health

DTIC Science & Technology

2016-10-01

AWARD NUMBER: W81XWH-15-1-0669 TITLE: The Use of Quantitative SPECT/CT Imaging to Assess Residual Limb Health PRINCIPAL INVESTIGATOR...3. DATES COVERED 30 Sep 2015 - 29 Sep 2016 4. TITLE AND SUBTITLE The Use of Quantitative SPECT/CT Imaging to Assess Residual Limb Health 5a...amputation and subsequently evaluate the utility of non-invasive imaging for evaluating the impact of next-generation socket technologies on the health of

GATE simulation of a new design of pinhole SPECT system for small animal brain imaging

NASA Astrophysics Data System (ADS)

Uzun Ozsahin, D.; Bläckberg, L.; El Fakhri, G.; Sabet, H.

2017-01-01

Small animal SPECT imaging has gained an increased interest over the past decade since it is an excellent tool for developing new drugs and tracers. Therefore, there is a huge effort on the development of cost-effective SPECT detectors with high capabilities. The aim of this study is to simulate the performance characteristics of new designs for a cost effective, stationary SPECT system dedicated to small animal imaging with a focus on mice brain. The conceptual design of this SPECT system platform, Stationary Small Animal SSA-SPECT, is to use many pixelated CsI:TI detector modules with 0.4 mm × 0.4 mm pixels in order to achieve excellent intrinsic detector resolution where each module is backed by a single pinhole collimator with 0.3 mm hole diameter. In this work, we present the simulation results of four variations of the SSA-SPECT platform where the number of detector modules and FOV size is varied while keeping the detector size and collimator hole size constant. Using the NEMA NU-4 protocol, we performed spatial resolution, sensitivity, image quality simulations followed by a Derenzo-like phantom evaluation. The results suggest that all four SSA-SPECT systems can provide better than 0.063% system sensitivity and < 1.5 mm FWHM spatial resolution without resolution recovery or other correction techniques. Specifically, SSA-SPECT-1 showed a system sensitivity of 0.09% in combination with 1.1 mm FWHM spatial resolution.

203Pb-Labeled Alpha-Melanocyte-Stimulating Hormone Peptide as an Imaging Probe for Melanoma Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yubin, Miao; Figueroa, Said D.; Fisher, Darrell R.

2008-05-01

Abbreviations: a-MSH; alpha melanocyte stimulating hormone, DOTA; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, Re(Arg11)CCMSH; DOTA-[Cys3,4,10, D-Phe7, Arg11]a-MSH3-13, NDP; [Nle4,d-Phe7] a-MSH3-13. Abstract Peptide-targeted alpha therapy with 200 mCi of 212Pb-DOTA-Re(Arg11)CCMSH cured 45% of B16/F1 murine melanoma-bearing C57 mice in a 120-day study, highlighting its melanoma treatment potential. However, there is a need to develop an imaging surrogate for patient specific dosimetry and to monitor the tumor response to 212Pb-DOTA-Re(Arg11)CCMSH therapy. The purpose of this study was to evaluate the potential of 203Pb-DOTA-Re(Arg11)CCMSH as a matched-pair SPECT imaging agent for 212Pb-DOTA-Re(Arg11)CCMSH. Method: DOTA-Re(Arg11)CCMSH was labeled with 203Pb in 0.5 M NH4OAc buffer at pH 5.4. Themore » internalization and efflux of 203Pb-DOTA-Re(Arg11)CCMSH were determined in B16/F1 melanoma cells. The pharmacokinetics of 203Pb-DOTA-Re(Arg11)CCMSH were examined in B16/F1 melanoma-bearing C57 mice. A micro-SPECT/CT imaging study was performed with 203Pb-DOTA-Re(Arg11)CCMSH in a B16/F1 melanoma-bearing C57 mouse at 2 h post-injection. Results: 203Pb-DOTA-Re(Arg11)CCMSH was easily prepared in NH4OAc buffer and completely separated from the excess non-radiolabeled peptide by RP-HPLC. 203Pb-DOTA-Re(Arg11)CCMSH displayed fast internalization and extended retention in B16/F1 cells. Approximately 73% of 203Pb-DOTA-Re(Arg11)CCMSH activity internalized after a 20-min incubation at 25C. After incubating the cells in culture media for 20 min, 78% of internalized activity remained in the cells. 203Pb-DOTA-Re(Arg11)CCMSH exhibited similar biodistribution pattern with 212Pb-DOTA-Re(Arg11)CCMSH in B16/F1 melanoma-bearing mice. 203Pb-DOTA-Re(Arg11)CCMSH exhibited the peak tumor uptake of 12.00 +/- 3.20 %ID/g at 1 h post-injection. The tumor uptake gradually decreased to 3.43 +/- 1.12 %ID/g at 48 h post-injection. 203Pb-DOTA-Re(Arg11)CCMSH exhibited the peak tumor to kidney uptake ratio of 1.53 at 2 h post-injection. The absorbed doses to the tumor and kidneys were 432 and 435 cGy/mCi, respectively. Whole-body clearance of 203Pb-DOTA-Re(Arg11)CCMSH was fast, with approximately 89% of the activity cleared through urinary system by 2 h post-injection. 203Pb showed 1.6 mm SPECT imaging resolution, which was comparable to 99mTc. Melanoma lesions were visualized through SPECT/CT images of 203Pb-DOTA-Re(Arg11)CCMSH at 2 h post-injection. Conclusions: 203Pb-DOTA-Re(Arg11)CCMSH exhibited favorable pharmacokinetic and tumor imaging properties, highlighting its potential as a matched-pair SPECT imaging agent for 212Pb-DOTA-Re(Arg11)CCMSH melanoma treatment.« less

High-resolution brain SPECT imaging by combination of parallel and tilted detector heads.

PubMed

Suzuki, Atsuro; Takeuchi, Wataru; Ishitsu, Takafumi; Morimoto, Yuichi; Kobashi, Keiji; Ueno, Yuichiro

2015-10-01

To improve the spatial resolution of brain single-photon emission computed tomography (SPECT), we propose a new brain SPECT system in which the detector heads are tilted towards the rotation axis so that they are closer to the brain. In addition, parallel detector heads are used to obtain the complete projection data set. We evaluated this parallel and tilted detector head system (PT-SPECT) in simulations. In the simulation study, the tilt angle of the detector heads relative to the axis was 45°. The distance from the collimator surface of the parallel detector heads to the axis was 130 mm. The distance from the collimator surface of the tilted detector heads to the origin on the axis was 110 mm. A CdTe semiconductor panel with a 1.4 mm detector pitch and a parallel-hole collimator were employed in both types of detector head. A line source phantom, cold-rod brain-shaped phantom, and cerebral blood flow phantom were evaluated. The projection data were generated by forward-projection of the phantom images using physics models, and Poisson noise at clinical levels was applied to the projection data. The ordered-subsets expectation maximization algorithm with physics models was used. We also evaluated conventional SPECT using four parallel detector heads for the sake of comparison. The evaluation of the line source phantom showed that the transaxial FWHM in the central slice for conventional SPECT ranged from 6.1 to 8.5 mm, while that for PT-SPECT ranged from 5.3 to 6.9 mm. The cold-rod brain-shaped phantom image showed that conventional SPECT could visualize up to 8-mm-diameter rods. By contrast, PT-SPECT could visualize up to 6-mm-diameter rods in upper slices of a cerebrum. The cerebral blood flow phantom image showed that the PT-SPECT system provided higher resolution at the thalamus and caudate nucleus as well as at the longitudinal fissure of the cerebrum compared with conventional SPECT. PT-SPECT provides improved image resolution at not only upper but also at central slices of the cerebrum.

Initial experience with SPECT imaging of the brain using I-123 p-iodoamphetamine in focal epilepsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

LaManna, M.M.; Sussman, N.M.; Harner, R.N.

1989-06-01

Nineteen patients with complex partial seizures refractory to medical treatment were examined with routine electroencephalography (EEG), video EEG monitoring, computed tomography or magnetic resonance imaging, neuropsychological tests and interictal single photon emission computed tomography (SPECT) with I-123 iodoamphetamine (INT). In 18 patients, SPECT identified areas of focal reduction in tracer uptake that correlated with the epileptogenic focus identified on the EEG. In addition, SPECT disclosed other areas of neurologic dysfunction as elicited on neuropsychological tests. Thus, IMP SPECT is a useful tool for localizing epileptogenic foci and their associated dynamic deficits.

A 3-dimensional mathematic cylinder phantom for the evaluation of the fundamental performance of SPECT.

PubMed

Onishi, Hideo; Motomura, Nobutoku; Takahashi, Masaaki; Yanagisawa, Masamichi; Ogawa, Koichi

2010-03-01

Degradation of SPECT images results from various physical factors. The primary aim of this study was the development of a digital phantom for use in the characterization of factors that contribute to image degradation in clinical SPECT studies. A 3-dimensional mathematic cylinder (3D-MAC) phantom was devised and developed. The phantom (200 mm in diameter and 200 mm long) comprised 3 imbedded stacks of five 30-mm-long cylinders (diameters, 4, 10, 20, 40, and 60 mm). In simulations, the 3 stacks and the background were assigned radioisotope concentrations and attenuation coefficients. SPECT projection datasets that included Compton scattering effects, photoelectric effects, and gamma-camera models were generated using the electron gamma-shower Monte Carlo simulation program. Collimator parameters, detector resolution, total photons acquired, number of projections acquired, and radius of rotation were varied in simulations. The projection data were formatted in Digital Imaging and Communications in Medicine (DICOM) and imported to and reconstructed using commercial reconstruction software on clinical SPECT workstations. Using the 3D-MAC phantom, we validated that contrast depended on size of region of interest (ROI) and was overestimated when the ROI was small. The low-energy general-purpose collimator caused a greater partial-volume effect than did the low-energy high-resolution collimator, and contrast in the cold region was higher using the filtered backprojection algorithm than using the ordered-subset expectation maximization algorithm in the SPECT images. We used imported DICOM projection data and reconstructed these data using vendor software; in addition, we validated reconstructed images. The devised and developed 3D-MAC SPECT phantom is useful for the characterization of various physical factors, contrasts, partial-volume effects, reconstruction algorithms, and such, that contribute to image degradation in clinical SPECT studies.

Added value of SPECT/spiral CT versus SPECT or CT alone in diagnosing solitary skeletal lesions.

PubMed

Zhang, Yiqiu; Li, Beilei; Shi, Hongcheng; Yu, Haojun; Gu, Yushen; Xiu, Yan

2017-08-14

The aim of this study was to investigate the added value of SPECT/spiral CT versus SPECT or CT alone in the differential diagnosis of solitary skeletal lesions. This was a retrospective study on a total of 69 patients who had a solitary skeletal "hot spot" that could not be definitively diagnosed using planar scintigraphy. Thus, SPECT/spiral CT was performed on the indeterminate lesions. SPECT, CT and SPECT/spiral CT images were independently interpreted by two experienced doctors who have both identification of CT and nuclear medicine. Each lesion was graded on a 4-point diagnostic scale (1: benign, 2: likely benign, 3: likely malignant, 4: malignant). The final diagnosis of each lesion was based on pathological confirmation after surgery within 3 weeks of the bone scan. Final diagnoses based on the pathological results revealed that 43 of the 69 patients were diagnosed with malignancy, and the remaining 26 patients were diagnosed as having benign lesions. For SPECT and CT scans, both of the reviewers rated 55.1 % (38/69) and 37.7 % (26/69) of lesions as equivocal, with the help of SPECT/CT, 33.3 % (23/69) of lesions were rated as equivocal. The diagnostic accuracies of SPECT, CT alone and SPECT/CT were 66.7 % (46/69) ,82.6 % (57/69) and 85.5 %(59/69), respectively. The kappa scores for the degree of agreement between SPECT, CT alone or SPECT/CT with pathological results were 0.185 (p = 0.054) , 0.612 (p < 0.001) and 0.671 (p < 0.001), respectively. Compared with SPECT or imaging alone, SPECT/spiral CT imaging was more accurate and valuable in the differential diagnosis of solitary skeletal lesions and resulted in significantly fewer equivocal findings.

Dual tracer imaging of SPECT and PET probes in living mice using a sequential protocol

PubMed Central

Chapman, Sarah E; Diener, Justin M; Sasser, Todd A; Correcher, Carlos; González, Antonio J; Avermaete, Tony Van; Leevy, W Matthew

2012-01-01

Over the past 20 years, multimodal imaging strategies have motivated the fusion of Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) scans with an X-ray computed tomography (CT) image to provide anatomical information, as well as a framework with which molecular and functional images may be co-registered. Recently, pre-clinical nuclear imaging technology has evolved to capture multiple SPECT or multiple PET tracers to further enhance the information content gathered within an imaging experiment. However, the use of SPECT and PET probes together, in the same animal, has remained a challenge. Here we describe a straightforward method using an integrated trimodal imaging system and a sequential dosing/acquisition protocol to achieve dual tracer imaging with 99mTc and 18F isotopes, along with anatomical CT, on an individual specimen. Dosing and imaging is completed so that minimal animal manipulations are required, full trimodal fusion is conserved, and tracer crosstalk including down-scatter of the PET tracer in SPECT mode is avoided. This technique will enhance the ability of preclinical researchers to detect multiple disease targets and perform functional, molecular, and anatomical imaging on individual specimens to increase the information content gathered within longitudinal in vivo studies. PMID:23145357

High-Resolution 4D Imaging of Technetium Transport in Porous Media using Preclinical SPECT-CT

NASA Astrophysics Data System (ADS)

Dogan, M.; DeVol, T. A.; Groen, H.; Moysey, S. M.; Ramakers, R.; Powell, B. A.

2015-12-01

Preclinical SPECT-CT (single-photon emission computed tomography with integrated X-ray computed tomography) offers the potential to quantitatively image the dynamic three-dimensional distribution of radioisotopes with sub-millimeter resolution, overlaid with structural CT images (20-200 micron resolution), making this an attractive method for studying transport in porous media. A preclinical SPECT-CT system (U-SPECT4CT, MILabs BV. Utrecht, The Netherlands) was evaluated for imaging flow and transport of 99mTc (t1/2=6hrs) using a 46,5mm by 156,4mm column packed with individual layers consisting of <0.2mm diameter silica gel, 0.2-0.25, 0.5, 1.0, 2.0, 3.0, and 4.0mm diameter glass beads, and a natural soil sample obtained from the Savannah River Site. The column was saturated with water prior to injecting the 99mTc solution. During the injection the flow was interrupted intermittently for 10 minute periods to allow for the acquisition of a SPECT image of the transport front. Non-uniformity of the front was clearly observed in the images as well as the retarded movement of 99mTc in the soil layer. The latter is suggesting good potential for monitoring transport processes occurring on the timescale of hours. After breakthrough of 99mTc was achieved, the flow was stopped and SPECT data were collected in one hour increments to evaluate the sensitivity of the instrument as the isotope decayed. Fused SPECT- CT images allowed for improved interpretation of 99mTc distributions within individual pore spaces. With ~3 MBq remaining in the column, the lowest activity imaged, it was not possible to clearly discriminate any of the pore spaces.

Development of Realistic Striatal Digital Brain (SDB) Phantom for 123I-FP-CIT SPECT and Effect on Ventricle in the Brain for Semi-quantitative Index of Specific Binding Ratio.

PubMed

Furuta, Akihiro; Onishi, Hideo; Nakamoto, Kenta

This study aimed at developing the realistic striatal digital brain (SDB) phantom and to assess specific binding ratio (SBR) for ventricular effect in the 123 I-FP-CIT SPECT imaging. SDB phantom was constructed in to four segments (striatum, ventricle, brain parenchyma, and skull bone) using Percentile method and other image processing in the T2-weighted MR images. The reference image was converted into 128×128 matrixes to align MR images with SPECT images. The process image was reconstructed with projection data sets generated from reference images additive blurring, attenuation, scatter, and statically noise. The SDB phantom was evaluated to find the accuracy of calculated SBR and to find the effect of SBR with/without ventricular counts with the reference and process images. We developed and investigated the utility of the SDB phantom in the 123 I-FP-CIT SPECT clinical study. The true value of SBR was just marched to calculate SBR from reference and process images. The SBR was underestimated 58.0% with ventricular counts in reference image, however, was underestimated 162% with ventricular counts in process images. The SDB phantom provides an extremely convenient tool for discovering basic properties of 123 I-FP-CIT SPECT clinical study image. It was suggested that the SBR was susceptible to ventricle.

Design of a Multi-Pinhole Collimator for I-123 DaTscan Imaging on Dual-Headed SPECT Systems in Combination with a Fan-Beam Collimator.

PubMed

King, Michael A; Mukherjee, Joyeeta M; Könik, Arda; Zubal, I George; Dey, Joyoni; Licho, Robert

2016-02-01

For the 2011 FDA approved Parkinson's Disease (PD) SPECT imaging agent I-123 labeled DaTscan, the volume of interest (VOI) is the interior portion of the brain. However imaging of the occipital lobe is also required with PD for calculation of the striatal binding ratio (SBR), a parameter of significance in early diagnosis, differentiation of PD from other disorders with similar clinical presentations, and monitoring progression. Thus we propose the usage of a combination of a multi-pinhole (MPH) collimator on one head of the SPECT system and a fan-beam on the other. The MPH would be designed to provide high resolution and sensitivity for imaging of the interior portion of the brain. The fan-beam collimator would provide lower resolution but complete sampling of the brain addressing data sufficiency and allowing a volume-of-interest to be defined over the occipital lobe for calculation of SBR's. Herein we focus on the design of the MPH component of the combined system. Combined reconstruction will be addressed in a subsequent publication. An analysis of 46 clinical DaTscan studies was performed to provide information to define the VOI, and design of a MPH collimator to image this VOI. The system spatial resolution for the MPH was set to 4.7 mm, which is comparable to that of clinical PET systems, and significantly smaller than that of fan-beam collimators employed in SPECT. With this set, we compared system sensitivities for three aperture array designs, and selected the 3 × 3 array due to it being the highest of the three. The combined sensitivity of the apertures for it was similar to that of an ultra-high resolution fan-beam (LEUHRF) collimator, but smaller than that of a high-resolution fan-beam collimator (LEHRF). On the basis of these results we propose the further exploration of this design through simulations, and the development of combined MPH and fan-beam reconstruction.

Brain SPECT Imaging in Complex Psychiatric Cases: An Evidence-Based, Underutilized Tool

PubMed Central

Amen, Daniel G; Trujillo, Manuel; Newberg, Andrew; Willeumier, Kristen; Tarzwell, Robert; Wu, Joseph C; Chaitin, Barry

2011-01-01

Over the past 20 years brain Single Photon Emission Computed Tomography (SPECT) imaging has developed a substantial, evidence-based foundation and is now recommended by professional societies for numerous indications relevant to psychiatric practice. Unfortunately, SPECT in clinical practice is utilized by only a handful of clinicians. This article presents a rationale for a more widespread use of SPECT in clinical practice for complex cases, and includes seven clinical applications where it may help optimize patient care. PMID:21863144

SU-E-I-20: Dead Time Count Loss Compensation in SPECT/CT: Projection Versus Global Correction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siman, W; Kappadath, S

Purpose: To compare projection-based versus global correction that compensate for deadtime count loss in SPECT/CT images. Methods: SPECT/CT images of an IEC phantom (2.3GBq 99mTc) with ∼10% deadtime loss containing the 37mm (uptake 3), 28 and 22mm (uptake 6) spheres were acquired using a 2 detector SPECT/CT system with 64 projections/detector and 15 s/projection. The deadtime, Ti and the true count rate, Ni at each projection, i was calculated using the monitor-source method. Deadtime corrected SPECT were reconstructed twice: (1) with projections that were individually-corrected for deadtime-losses; and (2) with original projections with losses and then correcting the reconstructed SPECTmore » images using a scaling factor equal to the inverse of the average fractional loss for 5 projections/detector. For both cases, the SPECT images were reconstructed using OSEM with attenuation and scatter corrections. The two SPECT datasets were assessed by comparing line profiles in xyplane and z-axis, evaluating the count recoveries, and comparing ROI statistics. Higher deadtime losses (up to 50%) were also simulated to the individually corrected projections by multiplying each projection i by exp(-a*Ni*Ti), where a is a scalar. Additionally, deadtime corrections in phantoms with different geometries and deadtime losses were also explored. The same two correction methods were carried for all these data sets. Results: Averaging the deadtime losses in 5 projections/detector suffices to recover >99% of the loss counts in most clinical cases. The line profiles (xyplane and z-axis) and the statistics in the ROIs drawn in the SPECT images corrected using both methods showed agreement within the statistical noise. The count-loss recoveries in the two methods also agree within >99%. Conclusion: The projection-based and the global correction yield visually indistinguishable SPECT images. The global correction based on sparse sampling of projections losses allows for accurate SPECT deadtime loss correction while keeping the study duration reasonable.« less

Image Restoration Using Functional and Anatomical Information Fusion with Application to SPECT-MRI Images

PubMed Central

Benameur, S.; Mignotte, M.; Meunier, J.; Soucy, J. -P.

2009-01-01

Image restoration is usually viewed as an ill-posed problem in image processing, since there is no unique solution associated with it. The quality of restored image closely depends on the constraints imposed of the characteristics of the solution. In this paper, we propose an original extension of the NAS-RIF restoration technique by using information fusion as prior information with application in SPECT medical imaging. That extension allows the restoration process to be constrained by efficiently incorporating, within the NAS-RIF method, a regularization term which stabilizes the inverse solution. Our restoration method is constrained by anatomical information extracted from a high resolution anatomical procedure such as magnetic resonance imaging (MRI). This structural anatomy-based regularization term uses the result of an unsupervised Markovian segmentation obtained after a preliminary registration step between the MRI and SPECT data volumes from each patient. This method was successfully tested on 30 pairs of brain MRI and SPECT acquisitions from different subjects and on Hoffman and Jaszczak SPECT phantoms. The experiments demonstrated that the method performs better, in terms of signal-to-noise ratio, than a classical supervised restoration approach using a Metz filter. PMID:19812704

The GOSTT concept and hybrid mixed/virtual/augmented reality environment radioguided surgery.

PubMed

Valdés Olmos, R A; Vidal-Sicart, S; Giammarile, F; Zaknun, J J; Van Leeuwen, F W; Mariani, G

2014-06-01

The popularity gained by the sentinel lymph node (SLN) procedure in the last two decades did increase the interest of the surgical disciplines for other applications of radioguided surgery. An example is the gamma-probe guided localization of occult or difficult to locate neoplastic lesions. Such guidance can be achieved by intralesional delivery (ultrasound, stereotaxis or CT) of a radiolabelled agent that remains accumulated at the site of the injection. Another possibility rested on the use of systemic administration of a tumour-seeking radiopharmaceutical with favourable tumour accumulation and retention. On the other hand, new intraoperative imaging devices for radioguided surgery in complex anatomical areas became available. All this a few years ago led to the delineation of the concept Guided intraOperative Scintigraphic Tumour Targeting (GOSTT) to include the whole spectrum of basic and advanced nuclear medicine procedures required for providing a roadmap that would optimise surgery. The introduction of allied signatures using, e.g. hybrid tracers for simultaneous detection of the radioactive and fluorescent signals did amply the GOSTT concept. It was now possible to combine perioperative nuclear medicine imaging with the superior resolution of additional optical guidance in the operating room. This hybrid approach is currently in progress and probably will become an important model to follow in the coming years. A cornerstone in the GOSTT concept is constituted by diagnostic imaging technologies like SPECT/CT. SPECT/CT was introduced halfway the past decade and was immediately incorporated into the SLN procedure. Important reasons attributing to the success of SPECT/CT were its combination with lymphoscintigraphy, and the ability to display SLNs in an anatomical environment. This latter aspect has significantly been improved in the new generation of SPECT/CT cameras and provides the base for the novel mixed reality protocols of image-guided surgery. In these protocols the generated virtual SPECT/CT elements are visually superimposed in the body of the patient in the operating room to directly facilitate, by means of visualization on screen or using head-mounted devices, the localization of radioactive and/or fluorescent targets by minimal invasive approaches in areas of complex anatomy. All these technological advances will play an increasing role in the future extension and the clinical impact of the GOSTT concept.

Co-registered perfusion SPECT/CT: utility for prediction of improved postoperative outcome in lung volume reduction surgery candidates.

PubMed

Takenaka, Daisuke; Ohno, Yoshiharu; Koyama, Hisanobu; Nogami, Munenobu; Onishi, Yumiko; Matsumoto, Keiko; Yoshikawa, Takeshi; Matsumoto, Sumiaki; Sugimura, Kazuro

2010-06-01

To directly compare the capabilities of perfusion scan, SPECT, co-registered SPECT/CT, and quantitatively and qualitatively assessed MDCT (i.e. quantitative CT and qualitative CT) for predicting postoperative clinical outcome for lung volume reduction surgery (LVRS) candidates. Twenty-five consecutive candidates (19 men and six women, age range: 42-72 years) for LVRS underwent preoperative CT and perfusion scan with SPECT. Clinical outcome of LVRS for all subjects was also assessed by determining the difference between pre- and postoperative forced expiratory volume in 1s (FEV(1)) and 6-min walking distance (6MWD). All SPECT examinations were performed on a SPECT scanner, and co-registered to thin-section CT by using commercially available software. On planar imaging, SPECT and SPECT/CT, upper versus lower zone or lobe ratios (U/Ls) were calculated from regional uptakes between upper and lower lung fields in the operated lung. On quantitatively assessed CT, U/L for all subjects was assessed from regional functional lung volumes. On qualitatively assessed CT, planar imaging, SPECT and co-registered SPECT/CT, U/Ls were assessed with a 4-point visual scoring system. To compare capabilities of predicting clinical outcome, each U/L was statistically correlated with the corresponding clinical outcome. Significantly fair or moderate correlations were observed between quantitatively and qualitatively assessed U/Ls obtained with all four methods and clinical outcomes (-0.60

MIRD Pamphlet No. 23: Quantitative SPECT for Patient-Specific 3-Dimensional Dosimetry in Internal Radionuclide Therapy

PubMed Central

Dewaraja, Yuni K.; Frey, Eric C.; Sgouros, George; Brill, A. Bertrand; Roberson, Peter; Zanzonico, Pat B.; Ljungberg, Michael

2012-01-01

In internal radionuclide therapy, a growing interest in voxel-level estimates of tissue-absorbed dose has been driven by the desire to report radiobiologic quantities that account for the biologic consequences of both spatial and temporal nonuniformities in these dose estimates. This report presents an overview of 3-dimensional SPECT methods and requirements for internal dosimetry at both regional and voxel levels. Combined SPECT/CT image-based methods are emphasized, because the CT-derived anatomic information allows one to address multiple technical factors that affect SPECT quantification while facilitating the patient-specific voxel-level dosimetry calculation itself. SPECT imaging and reconstruction techniques for quantification in radionuclide therapy are not necessarily the same as those designed to optimize diagnostic imaging quality. The current overview is intended as an introduction to an upcoming series of MIRD pamphlets with detailed radionuclide-specific recommendations intended to provide best-practice SPECT quantification–based guidance for radionuclide dosimetry. PMID:22743252

Direct comparison of rest and adenosine stress myocardial perfusion CT with rest and stress SPECT

PubMed Central

Okada, David R.; Ghoshhajra, Brian B.; Blankstein, Ron; Rocha-Filho, Jose A.; Shturman, Leonid D.; Rogers, Ian S.; Bezerra, Hiram G.; Sarwar, Ammar; Gewirtz, Henry; Hoffmann, Udo; Mamuya, Wilfred S.; Brady, Thomas J.; Cury, Ricardo C.

2010-01-01

Introduction We have recently described a technique for assessing myocardial perfusion using adenosine-mediated stress imaging (CTP) with dual source computed tomography. SPECT myocardial perfusion imaging (SPECT-MPI) is a widely utilized and extensively validated method for assessing myocardial perfusion. The aim of this study was to determine the level of agreement between CTP and SPECT-MPI at rest and under stress on a per-segment, per-vessel, and per-patient basis. Methods Forty-seven consecutive patients underwent CTP and SPECT-MPI. Perfusion images were interpreted using the 17 segment AHA model and were scored on a 0 (normal) to 3 (abnormal) scale. Summed rest and stress scores were calculated for each vascular territory and patient by adding corresponding segmental scores. Results On a per-segment basis (n = 799), CTP and SPECT-MPI demonstrated excellent correlation: Goodman-Kruskall γ = .59 (P < .0001) for stress and .75 (P < .0001) for rest. On a per-vessel basis (n = 141), CTP and SPECT-MPI summed scores demonstrated good correlation: Pearson r = .56 (P < .0001) for stress and .66 (P < .0001) for rest. On a per-patient basis (n = 47), CTP and SPECT-MPI demonstrated good correlation: Pearson r = .60 (P < .0001) for stress and .76 (P < .0001) for rest. Conclusions CTP compares favorably with SPECT-MPI for detection, extent, and severity of myocardial perfusion defects at rest and stress. PMID:19936863

Incremental diagnostic accuracy of hybrid SPECT/CT coronary angiography in a population with an intermediate to high pre-test likelihood of coronary artery disease.

PubMed

Schaap, Jeroen; Kauling, Robert M; Boekholdt, S Matthijs; Nieman, Koen; Meijboom, W Bob; Post, Martijn C; Van der Heyden, Jan A; de Kroon, Thom L; van Es, H Wouter; Rensing, Benno J; Verzijlbergen, J Fred

2013-07-01

Hybrid myocardial perfusion imaging with single photon emission computed tomography (SPECT) and CT coronary angiography (CCTA) has the potential to play a major role in patients with non-conclusive SPECT or CCTA results. We evaluated the performance of hybrid SPECT/CCTA vs. standalone SPECT and CCTA for the diagnosis of significant coronary artery disease (CAD) in patients with an intermediate to high pre-test likelihood of CAD. In total, 98 patients (mean age 62.5 ± 10.1 years, 68.4% male) with stable anginal complaints and a median pre-test likelihood of 87% (range 22-95%) were prospectively included in this study. Hybrid SPECT/CCTA was performed prior to conventional coronary angiography (CA) including fractional flow reserve (FFR) measurements. Hybrid analysis was performed by combined interpretation of SPECT and CCTA images. The sensitivity, specificity, positive (PPV), and negative (NPV) predictive values were calculated for standalone SPECT, CCTA, and hybrid SPECT/CCTA on per patient level, using an FFR <0.80 as a reference for significant CAD. Significant CAD was demonstrated in 56 patients (57.9%). Non-conclusive SPECT or CCTA results were found in 32 (32.7%) patients. SPECT had a sensitivity of 93%, specificity 79%, PPV 85%, and NPV 89%. CCTA had a sensitivity of 98%, specificity 62%, PPV 77%, and NPV 96%. Hybrid analysis of SPECT and CCTA improved the overall performance: sensitivity, specificity, PPV, and NPV for the presence of significant CAD to 96, 95, 96, and 95%, respectively. In > 40% of the patients with a high pre-test likelihood no significant CAD was demonstrated, emphasizing the value of accurate pre-treatment cardiovascular imaging. Hybrid SPECT/CCTA was able to accurately diagnose and exclude significant CAD surpassing standalone myocardial SPECT and CCTA, vs. a reference standard of FFR measurements.

Progress in SPECT/CT imaging of prostate cancer.

PubMed

Seo, Youngho; Franc, Benjamin L; Hawkins, Randall A; Wong, Kenneth H; Hasegawa, Bruce H

2006-08-01

Prostate cancer is the most common type of cancer (other than skin cancer) among men in the United States. Although prostate cancer is one of the few cancers that grow so slowly that it may never threaten the lives of some patients, it can be lethal once metastasized. Indium-111 capromab pendetide (ProstaScint, Cytogen Corporation, Princeton, NJ) imaging is indicated for staging and recurrence detection of the disease, and is particularly useful to determine whether or not the disease has spread to distant metastatic sites. However, the interpretation of 111In-capromab pendetide is challenging without correlated structural information mostly because the radiopharmaceutical demonstrates nonspecific uptake in the normal vasculature, bowel, bone marrow, and the prostate gland. We developed an improved method of imaging and localizing 111In-Capromab pendetide using a SPECT/CT imaging system. The specific goals included: i) development and application of a novel iterative SPECT reconstruction algorithm that utilizes a priori information from coregistered CT; and ii) assessment of clinical impact of adding SPECT/CT for prostate cancer imaging with capromab pendetide utilizing the standard and novel reconstruction techniques. Patient imaging studies with capromab pendetide were performed from 1999 to 2004 using two different SPECT/CT scanners, a prototype SPECT/CT system and a commercial SPECT/CT system (Discovery VH, GE Healthcare, Waukesha, WI). SPECT projection data from both systems were reconstructed using an experimental iterative algorithm that compensates for both photon attenuation and collimator blurring. In addition, the data obtained from the commercial system were reconstructed with attenuation correction using an OSEM reconstruction supplied by the camera manufacturer for routine clinical interpretation. For 12 sets of patient data, SPECT images reconstructed using the experimental algorithm were interpreted separately and compared with interpretation of images obtained using the standard reconstruction technique. The experimental reconstruction algorithm improved spatial resolution, reduced streak artifacts, and yielded a better correlation with anatomic details of CT in comparison to conventional reconstruction methods (e.g., filtered back-projection or OSEM with attenuation correction only). Images produced with the experimental algorithm produced a subjective improvement in the confidence of interpretation for 11 of 12 studies. There were also changes in interpretations for 4 of 12 studies although the changes were not sufficient to alter prognosis or the patient treatment plan.

Evaluation of Timepix3 based CdTe photon counting detector for fully spectroscopic small animal SPECT imaging

NASA Astrophysics Data System (ADS)

Trojanova, E.; Jakubek, J.; Turecek, D.; Sykora, V.; Francova, P.; Kolarova, V.; Sefc, L.

2018-01-01

The imaging method of SPECT (Single Photon Emission Computed Tomography) is used in nuclear medicine for diagnostics of various diseases or organs malfunctions. The distribution of medically injected, inhaled, or ingested radionuclides (radiotracers) in the patient body is imaged using gamma-ray sensitive camera with suitable imaging collimator. The 3D image is then calculated by combining many images taken from different observation angles. Most of SPECT systems use scintillator based cameras. These cameras do not provide good energy resolution and do not allow efficient suppression of unwanted signals such as those caused by Compton scattering. The main goal of this work is evaluation of Timepix3 detector properties for SPECT method for functional imaging of small animals during preclinical studies. Advantageous Timepix3 properties such as energy and spatial resolution are exploited for significant image quality improvement. Preliminary measurements were performed on specially prepared plastic phantom with cavities filled by radioisotopes and then repeated with in vivo mouse sample.

[Development of a Striatal and Skull Phantom for Quantitative 123I-FP-CIT SPECT].

PubMed

Ishiguro, Masanobu; Uno, Masaki; Miyazaki, Takuma; Kataoka, Yumi; Toyama, Hiroshi; Ichihara, Takashi

123 Iodine-labelled N-(3-fluoropropyl) -2β-carbomethoxy-3β-(4-iodophenyl) nortropane ( 123 I-FP-CIT) single photon emission computerized tomography (SPECT) images are used for differential diagnosis such as Parkinson's disease (PD). Specific binding ratio (SBR) is affected by scattering and attenuation in SPECT imaging, because gender and age lead to changes in skull density. It is necessary to clarify and correct the influence of the phantom simulating the the skull. The purpose of this study was to develop phantoms that can evaluate scattering and attenuation correction. Skull phantoms were prepared based on the measuring the results of the average computed tomography (CT) value, average skull thickness of 12 males and 16 females. 123 I-FP-CIT SPECT imaging of striatal phantom was performed with these skull phantoms, which reproduced normal and PD. SPECT images, were reconstructed with scattering and attenuation correction. SBR with partial volume effect corrected (SBR act ) and conventional SBR (SBR Bolt ) were measured and compared. The striatum and the skull phantoms along with 123 I-FP-CIT were able to reproduce the normal accumulation and disease state of PD and further those reproduced the influence of skull density on SPECT imaging. The error rate with the true SBR, SBR act was much smaller than SBR Bolt . The effect on SBR could be corrected by scattering and attenuation correction even if the skull density changes with 123 I-FP-CIT on SPECT imaging. The combination of triple energy window method and CT-attenuation correction method would be the best correction method for SBR act .

Activity concentration measurements using a conjugate gradient (Siemens xSPECT) reconstruction algorithm in SPECT/CT.

PubMed

Armstrong, Ian S; Hoffmann, Sandra A

2016-11-01

The interest in quantitative single photon emission computer tomography (SPECT) shows potential in a number of clinical applications and now several vendors are providing software and hardware solutions to allow 'SUV-SPECT' to mirror metrics used in PET imaging. This brief technical report assesses the accuracy of activity concentration measurements using a new algorithm 'xSPECT' from Siemens Healthcare. SPECT/CT data were acquired from a uniform cylinder with 5, 10, 15 and 20 s/projection and NEMA image quality phantom with 25 s/projection. The NEMA phantom had hot spheres filled with an 8 : 1 activity concentration relative to the background compartment. Reconstructions were performed using parameters defined by manufacturer presets available with the algorithm. The accuracy of activity concentration measurements was assessed. A dose calibrator-camera cross-calibration factor (CCF) was derived from the uniform phantom data. In uniform phantom images, a positive bias was observed, ranging from ∼6% in the lower count images to ∼4% in the higher-count images. On the basis of the higher-count data, a CCF of 0.96 was derived. As expected, considerable negative bias was measured in the NEMA spheres using region mean values whereas positive bias was measured in the four largest NEMA spheres. Nonmonotonically increasing recovery curves for the hot spheres suggested the presence of Gibbs edge enhancement from resolution modelling. Sufficiently accurate activity concentration measurements can easily be measured on images reconstructed with the xSPECT algorithm without a CCF. However, the use of a CCF is likely to improve accuracy further. A manual conversion of voxel values into SUV should be possible, provided that the patient weight, injected activity and time between injection and imaging are all known accurately.

Radiotracer Imaging Allows for Noninvasive Detection and Quantification of Abnormalities in Angiosome Foot Perfusion in Diabetic Patients With Critical Limb Ischemia and Nonhealing Wounds

PubMed Central

Alvelo, Jessica L.; Papademetris, Xenophon; Mena-Hurtado, Carlos; Jeon, Sangchoon; Sumpio, Bauer E.; Sinusas, Albert J.

2018-01-01

Background: Single photon emission computed tomography (SPECT)/computed tomography (CT) imaging allows for assessment of skeletal muscle microvascular perfusion but has not been quantitatively assessed in angiosomes, or 3-dimensional vascular territories, of the foot. This study assessed and compared resting angiosome foot perfusion between healthy subjects and diabetic patients with critical limb ischemia (CLI). Additionally, the relationship between SPECT/CT imaging and the ankle–brachial index—a standard tool for evaluating peripheral artery disease—was assessed. Methods and Results: Healthy subjects (n=9) and diabetic patients with CLI and nonhealing ulcers (n=42) underwent SPECT/CT perfusion imaging of the feet. CT images were segmented into angiosomes for quantification of relative radiotracer uptake, expressed as standardized uptake values. Standardized uptake values were assessed in ulcerated angiosomes of patients with CLI and compared with whole-foot standardized uptake values in healthy subjects. Serial SPECT/CT imaging was performed to assess uptake kinetics of technetium-99m-tetrofosmin. The relationship between angiosome perfusion and ankle–brachial index was assessed via correlational analysis. Resting perfusion was significantly lower in CLI versus healthy subjects (P=0.0007). Intraclass correlation coefficients of 0.95 (healthy) and 0.93 (CLI) demonstrated excellent agreement between serial perfusion measurements. Correlational analysis, including healthy and CLI subjects, demonstrated a significant relationship between ankle–brachial index and SPECT/CT (P=0.01); however, this relationship was not significant for diabetic CLI patients only (P=0.2). Conclusions: SPECT/CT imaging assesses regional foot perfusion and detects abnormalities in microvascular perfusion that may be undetectable by conventional ankle–brachial index in patients with diabetes mellitus. SPECT/CT may provide a novel approach for evaluating responses to targeted therapies. PMID:29748311

Iodine-131 imaging using 284 keV photons with a small animal CZT-SPECT system dedicated to low-medium-energy photon detection.

PubMed

Kojima, Akihiro; Gotoh, Kumiko; Shimamoto, Masako; Hasegawa, Koki; Okada, Seiji

2016-02-01

Iodine-131 is widely used for radionuclide therapy because of its β-particle and for diagnostic imaging employing its principal gamma ray. Since that principal gamma ray has the relatively high energy of 364 keV, small animal single-photon emission computed tomography (SPECT) imaging systems may be required to possess the ability to image such higher energy photons. The aim of this study was to investigate the possibility of imaging I-131 using its 284 keV photons instead of its 364 keV photons in a small animal SPECT imaging system dedicated to the detection of low-medium-energy photons (below 300 keV). The imaging system used was a commercially available preclinical SPECT instrument with CZT detectors that was equipped with multi-pinhole collimators and was accompanied by a CT imager. An energy window for I-131 imaging was set to a photopeak of 284 keV with a low abundance compared with 364 keV photons. Small line sources and two mice, one of each of two types, that were injected with NaI-131 were scanned. Although higher counts occurred at the peripheral region of the reconstructed images due to the collimator penetration by the 364 keV photons, the shape of the small line sources could be well visualized. The measured spatial resolution was relatively poor (~1.9 mm for full width at half maximum and ~3.9 mm for full width at tenth maximum). However, a good linear correlation between SPECT values and the level of I-131 radioactivity was observed. Furthermore, the uptake of NaI-131 to the thyroid gland for the two mice was clearly identified in the 3D-SPECT image fused with the X-ray CT image. We conclude that the use of an energy window set on the photopeak of 284 keV and the multi-pinhole collimator may permit I-131 imaging for a preclinical CZT-SPECT system that does not have the ability to acquire images using the 364 keV photons.

Synthesis and Preclinical Evaluation of Radioiodinated Hypericin Dicarboxylic Acid as a Necrosis Avid Agent in Rat Models of Induced Hepatic, Muscular, and Myocardial Necroses.

PubMed

Li, Jindian; Zhang, Jian; Yang, Shengwei; Jiang, Cuihua; Zhang, DongJian; Jin, Qiaomei; Wang, Qin; Wang, Cong; Ni, Yicheng; Yin, Zhiqi; Song, Shaoli

2016-01-04

Myocardial infarction (MI) leads to substantial morbidity and mortality around the world. Accurate assessment of myocardial viability is essential to assist therapies and improve patient outcomes. (131)I-hypericin dicarboxylic acid ((131)I-HDA) was synthesized and evaluated as a potential diagnostic agent for earlier assessment of myocardium viability compared to its preceding counterpart (131)I-hypericin ((131)I-Hyp) with strong hydrophobic property, long plasma half-life, and high uptake in mononuclear phagocyte system (MPS). Herein, HDA was synthesized and characterized, and self-aggregation constant Kα was analyzed by spectrophotometry. Plasma half-life was determined in healthy rats by γ-counting. (131)I-HDA and (131)I-Hyp were prepared with iodogen as oxidant. In vitro necrosis avidity of (131)I-HDA and (131)I-Hyp was evaluated in necrotic cells induced by hyperthermia. Biodistribution was determined in rat models of induced necrosis using γ-counting, autoradiography, and histopathology. Earlier imaging of necrotic myocardium to assess myocardial viability was performed in rat models of reperfused myocardium infarction using single photon emission computed tomography/computed tomography (SPECT/CT). As a result, the self-aggregation constant Kα of HDA was lower than that of Hyp (105602 vs 194644, p < 0.01). (131)I-HDA displayed a shorter blood half-life compared with (131)I-Hyp (9.21 vs 31.20 h, p < 0.01). The necrotic-viable ratio in cells was higher with (131)I-HDA relative to that with (131)I-Hyp (5.48 vs 4.63, p < 0.05). (131)I-HDA showed a higher necrotic-viable myocardium ratio (7.32 vs 3.20, p < 0.01), necrotic myocardium-blood ratio (3.34 vs 1.74, p < 0.05), and necrotic myocardium-lung ratio (3.09 vs 0.61, p < 0.01) compared with (131)I-Hyp. (131)I-HDA achieved imaging of necrotic myocardium at 6 h postinjection (p.i.) with SPECT/CT, earlier than what (131)I-Hyp did. Therefore, (131)I-HDA may serve as a promising necrosis-avid diagnostic agent for earlier imaging of necrotic myocardium compared with (131)I-Hyp. This may support further development of radiopharmaceuticals ((123)I and (99m)Tc) based on HDA for SPECT/CT of necrotic myocardium.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

It has been five years since the last in-depth American College of Nuclear Physicians/Society of Nuclear Medicine Symposium on the subject of single photon emission computed tomography (SPECT) was held. Because this subject was nominated as the single most desired topic we have selected SPECT imaging as the basis for this year's program. The objectives of this symposium are to survey the progress of SPECT clinical applications that have taken place over the last five years and to provide practical and timely guidelines to users of SPECT so that this exciting imaging modality can be fully integrated into the evaluationmore » of pathologic processes. The first half was devoted to a consideration of technical factors important in SPECT acquisition and the second half was devoted to those organ systems about which sufficient clinical SPECT imaging data are available. With respect to the technical aspect of the program we have selected the key areas which demand awareness and attention in order to make SPECT operational in clinical practice. These include selection of equipment, details of uniformity correction, utilization of phantoms for equipment acceptance and quality assurance, the major aspect of algorithms, an understanding of filtered back projection and appropriate choice of filters and an awareness of the most commonly generated artifacts and how to recognize them. With respect to the acquisition and interpretation of organ images, the faculty will present information on the major aspects of hepatic, brain, cardiac, skeletal, and immunologic imaging techniques. Individual papers are processed separately for the data base. (TEM)« less

Impact of the Adaptive Statistical Iterative Reconstruction Technique on Radiation Dose and Image Quality in Bone SPECT/CT.

PubMed

Sibille, Louis; Chambert, Benjamin; Alonso, Sandrine; Barrau, Corinne; D'Estanque, Emmanuel; Al Tabaa, Yassine; Collombier, Laurent; Demattei, Christophe; Kotzki, Pierre-Olivier; Boudousq, Vincent

2016-07-01

The purpose of this study was to compare a routine bone SPECT/CT protocol using CT reconstructed with filtered backprojection (FBP) with an optimized protocol using low-dose CT images reconstructed with adaptive statistical iterative reconstruction (ASiR). In this prospective study, enrolled patients underwent bone SPECT/CT, with 1 SPECT acquisition followed by 2 randomized CT acquisitions: FBP CT (FBP; noise index, 25) and ASiR CT (70% ASiR; noise index, 40). The image quality of both attenuation-corrected SPECT and CT images was visually (5-point Likert scale, 2 interpreters) and quantitatively (contrast ratio [CR] and signal-to-noise ratio [SNR]) estimated. The CT dose index volume, dose-length product, and effective dose were compared. Seventy-five patients were enrolled in the study. Quantitative attenuation-corrected SPECT evaluation showed no inferiority for contrast ratio and SNR issued from FBP CT or ASiR CT (respectively, 13.41 ± 7.83 vs. 13.45 ± 7.99 and 2.33 ± 0.83 vs. 2.32 ± 0.84). Qualitative image analysis showed no difference between attenuation-corrected SPECT images issued from FBP CT or ASiR CT for both interpreters (respectively, 3.5 ± 0.6 vs. 3.5 ± 0.6 and 3.6 ± 0.5 vs. 3.6 ± 0.5). Quantitative CT evaluation showed no inferiority for SNR between FBP and ASiR CT images (respectively, 0.93 ± 0.16 and 1.07 ± 0.17). Qualitative image analysis showed no quality difference between FBP and ASiR CT images for both interpreters (respectively, 3.8 ± 0.5 vs. 3.6 ± 0.5 and 4.0 ± 0.1 vs. 4.0 ± 0.2). Mean CT dose index volume, dose-length product, and effective dose for ASiR CT (3.0 ± 2.0 mGy, 148 ± 85 mGy⋅cm, and 2.2 ± 1.3 mSv) were significantly lower than for FBP CT (8.5 ± 3.7 mGy, 365 ± 160 mGy⋅cm, and 5.5 ± 2.4 mSv). The use of 70% ASiR blending in bone SPECT/CT can reduce the CT radiation dose by 60%, with no sacrifice in attenuation-corrected SPECT and CT image quality, compared with the conventional protocol using FBP CT reconstruction technique. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Hybrid imaging by SPECT/CT for sentinel lymph node detection in patients with cancer of the uterine cervix.

PubMed

Martínez, A; Zerdoud, S; Mery, E; Bouissou, E; Ferron, G; Querleu, D

2010-12-01

Conventional lymphoscintigraphy provides planar images with little spatial information on location of pelvic sentinel lymph nodes (SLN). SPECT has better spatial resolution and, in combination with anatomic accuracy provided by CT improves SLN preoperative localization. The aim of the study was to report on the results of hybrid imaging of SLN in early cervical cancer patients treated at Claudius Regaud Cancer Center. Stages IA-IB1 cervical cancer patients undergoing preoperative SPECT/CT for SLN detection were analysed. Forty-one patients were included. A 100% SLN detection rate was achieved when a combined technique (radiotracer and blue dye) was used. At least one SLN was clearly visualized by SPECT/CT in 39 of 41 patients (95%) and full anatomic concordance with intraoperative anatomical location of SLN was found in 37 of the 39 patients with at least one SLN identified by SPECT/CT (95%). Location of removed SLN included the external and internal iliac area in 88% patients, the common iliac area in 10.5%, and the inframesenteric para-aortic area in 1.5%. No SLN was found in the infrarenal para-aortic region. Lymph node involvement was identified in 5 patients (12.1%). SLN correctly predicted lymph node involvement in all node-positive patients. However, SPECT/CT failed to identify 1 of the 5 metastatic SLN. SPECT/CT accurately detected preoperative SLN topography and enhanced diagnostic sensitivity of SLN imaging, improving surgical approach to patients with cervical cancer staging. Diagnostic quality of anatomic landmarks of CT images of SPECT/CT could be further improved by the use of contrast injected CT. Copyright © 2010 Elsevier Inc. All rights reserved.

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

NASA Astrophysics Data System (ADS)

Kowalczyk, L.; Goszczynska, H.; Zalewska, E.; Bajera, A.; Krolicki, L.

2014-04-01

This work was performed as part of a larger research concerning the feasibility of improving the localization of epileptic foci, as compared to the standard SPECT examination, by applying the technique of EEG mapping. The presented study extends our previous work on the development of a method for superposition of SPECT images and EEG 3D maps when these two examinations are performed simultaneously. Due to the lack of anatomical data in SPECT images it is a much more difficult task than in the case of MRI/EEG study where electrodes are visible in morphological images. Using the appropriate dose of radioisotope we mark five base electrodes to make them visible in the SPECT image and then approximate the coordinates of the remaining electrodes using properties of the 10-20 electrode placement system and the proposed nine-ellipses model. This allows computing a sequence of 3D EEG maps spanning on all electrodes. It happens, however, that not all five base electrodes can be reliably identified in SPECT data. The aim of the current study was to develop a method for determining the coordinates of base electrode(s) missing in the SPECT image. The algorithm for coordinates approximation has been developed and was tested on data collected for three subjects with all visible electrodes. To increase the accuracy of the approximation we used head surface models. Freely available model from Oostenveld research based on data from SPM package and our own model based on data from our EEG/SPECT studies were used. For data collected in four cases with one electrode not visible we compared the invisible base electrode coordinates approximation for Oostenveld and our models. The results vary depending on the missing electrode placement, but application of the realistic head model significantly increases the accuracy of the approximation.

Advances in PET myocardial perfusion imaging: F-18 labeled tracers.

PubMed

Rischpler, Christoph; Park, Min-Jae; Fung, George S K; Javadi, Mehrbod; Tsui, Benjamin M W; Higuchi, Takahiro

2012-01-01

Coronary artery disease and its related cardiac disorders represent the most common cause of death in the USA and Western world. Despite advancements in treatment and accompanying improvements in outcome with current diagnostic and therapeutic modalities, it is the correct assignment of these diagnostic techniques and treatment options which are crucial. From a diagnostic standpoint, SPECT myocardial perfusion imaging (MPI) using traditional radiotracers like thallium-201 chloride, Tc-99m sestamibi or Tc-99m tetrofosmin is the most utilized imaging technique. However, PET MPI using N-13 ammonia, rubidium-82 chloride or O-15 water is increasing in availability and usage as a result of the growing number of medical centers with new-generation PET/CT systems taking advantage of the superior imaging properties of PET over SPECT. The routine clinical use of PET MPI is still limited, in part because of the short half-life of conventional PET MPI tracers. The disadvantages of these conventional PET tracers include expensive onsite production and inconvenient on-scanner tracer administration making them unsuitable for physical exercise stress imaging. Recently, two F-18 labeled radiotracers with longer radioactive half-lives than conventional PET imaging agents have been introduced. These are flurpiridaz F 18 (formerly known as F-18 BMS747158-02) and F-18 fluorobenzyltriphenylphosphonium. These longer half-life F-18 labeled perfusion tracers can overcome the production and protocol limitations of currently used radiotracers for PET MPI.

A novel computer-assisted image analysis of [123I]β-CIT SPECT images improves the diagnostic accuracy of parkinsonian disorders.

PubMed

Goebel, Georg; Seppi, Klaus; Donnemiller, Eveline; Warwitz, Boris; Wenning, Gregor K; Virgolini, Irene; Poewe, Werner; Scherfler, Christoph

2011-04-01

The purpose of this study was to develop an observer-independent algorithm for the correct classification of dopamine transporter SPECT images as Parkinson's disease (PD), multiple system atrophy parkinson variant (MSA-P), progressive supranuclear palsy (PSP) or normal. A total of 60 subjects with clinically probable PD (n = 15), MSA-P (n = 15) and PSP (n = 15), and 15 age-matched healthy volunteers, were studied with the dopamine transporter ligand [(123)I]β-CIT. Parametric images of the specific-to-nondisplaceable equilibrium partition coefficient (BP(ND)) were generated. Following a voxel-wise ANOVA, cut-off values were calculated from the voxel values of the resulting six post-hoc t-test maps. The percentages of the volume of an individual BP(ND) image remaining below and above the cut-off values were determined. The higher percentage of image volume from all six cut-off matrices was used to classify an individual's image. For validation, the algorithm was compared to a conventional region of interest analysis. The predictive diagnostic accuracy of the algorithm in the correct assignment of a [(123)I]β-CIT SPECT image was 83.3% and increased to 93.3% on merging the MSA-P and PSP groups. In contrast the multinomial logistic regression of mean region of interest values of the caudate, putamen and midbrain revealed a diagnostic accuracy of 71.7%. In contrast to a rater-driven approach, this novel method was superior in classifying [(123)I]β-CIT-SPECT images as one of four diagnostic entities. In combination with the investigator-driven visual assessment of SPECT images, this clinical decision support tool would help to improve the diagnostic yield of [(123)I]β-CIT SPECT in patients presenting with parkinsonism at their initial visit.

Crossed Cerebellar Tracer Uptake on Acute-Stage 123I-Iomazenil SPECT Imaging Predicts 3-Month Functional Outcome in Patients With Nonfatal Hypertensive Putaminal or Thalamic Hemorrhage.

PubMed

Kojima, Daigo; Komoribayashi, Nobukazu; Omama, Shinichi; Oikawa, Kohki; Fujiwara, Shunrou; Kobayashi, Masakazu; Kubo, Yoshitaka; Terasaki, Kazunori; Ogasawara, Kuniaki

2018-06-01

Whereas SPECT images obtained 180 minutes after administration of I-iomazenil (IMZ) (late images) are proportional to the distribution of central benzodiazepine receptor-binding potential, SPECT images obtained within 30 minutes after I-IMZ administration (early images) correlate with regional brain perfusion. The aim of the present study was to determine whether crossed cerebellar tracer uptake on acute-stage I-IMZ SPECT imaging predicts 3-month functional outcome in patients with nonfatal hypertensive putaminal or thalamic hemorrhage. Forty-six patients underwent early and late SPECT imaging with I-IMZ within 7 days after the onset of hemorrhage. A region of interest was automatically placed in the bilateral cerebellar hemispheres using a 3-dimensional stereotaxic region-of-interest template, and the ratio of the value in the cerebellar hemisphere contralateral to the affected side to that in the ipsilateral cerebellar hemisphere (ARcbl) was calculated in each patient. Each patient's physical function was measured using the modified Rankin scale (mRS) score 3 months after onset. The ARcbl on early (ρ = -0.511, P = 0.0003) and late (ρ = -0.714, P < 0.0001) images correlated with the mRS 3 months after the onset of hemorrhage. Multivariate analysis showed that only a low ARcbl in late images was significantly associated with a poor functional outcome (mRS score ≥3 at 3 months after onset) (95% confidence interval, 0.001-0.003; P = 0.0212). Crossed cerebellar tracer uptake on acute-stage I-IMZ SPECT imaging predicts 3-month functional outcome in patients with nonfatal hypertensive putaminal or thalamic hemorrhage.

Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations.

PubMed

Montes, Carlos; Tamayo, Pilar; Hernandez, Jorge; Gomez-Caminero, Felipe; García, Sofia; Martín, Carlos; Rosero, Angela

2013-08-01

Hybrid imaging, such as SPECT/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose.

Novel SPECT Technologies and Approaches in Cardiac Imaging

PubMed Central

Slomka, Piotr; Hung, Guang-Uei; Germano, Guido; Berman, Daniel S.

2017-01-01

Recent novel approaches in myocardial perfusion single photon emission CT (SPECT) have been facilitated by new dedicated high-efficiency hardware with solid-state detectors and optimized collimators. New protocols include very low-dose (1 mSv) stress-only, two-position imaging to mitigate attenuation artifacts, and simultaneous dual-isotope imaging. Attenuation correction can be performed by specialized low-dose systems or by previously obtained CT coronary calcium scans. Hybrid protocols using CT angiography have been proposed. Image quality improvements have been demonstrated by novel reconstructions and motion correction. Fast SPECT acquisition facilitates dynamic flow and early function measurements. Image processing algorithms have become automated with virtually unsupervised extraction of quantitative imaging variables. This automation facilitates integration with clinical variables derived by machine learning to predict patient outcome or diagnosis. In this review, we describe new imaging protocols made possible by the new hardware developments. We also discuss several novel software approaches for the quantification and interpretation of myocardial perfusion SPECT scans. PMID:29034066

Towards simultaneous single emission microscopy and magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Cai, Liang

In recent years, the combined nuclear imaging and magnetic resonance imaging (MRI) has drawn extensive research effort. They can provide simultaneously acquired anatomical and functional information inside the human/small animal body in vivo. In this dissertation, the development of an ultrahigh resolution MR-compatible SPECT (Single Photon Emission Computed Tomography) system that can be operated inside a pre-existing clinical MR scanner for simultaneous dual-modality imaging of small animals will be discussed. This system is constructed with 40 small pixel CdTe detector modules assembled in a fully stationary ring SPECT geometry. Series of experiments have demonstrated that this system is capable of providing an imaging resolution of <500?m, when operated inside MR scanners. The ultrahigh resolution MR-compatible SPECT system is built around a small pixel CdTe detector module that we recently developed. Each module consists of CdTe detectors having an overall size of 2.2 cm x 1.1 cm, divided into 64 x 32 pixels of 350 mum in size. A novel hybrid pixel-waveform (HPWF) readout system is also designed to alleviate several challenges for using small-pixel CdTe detectors in ultrahigh-resolution SPECT imaging applications. The HPWF system utilizes a modified version of a 2048-channel 2-D CMOS ASIC to readout the anode pixel, and a digitizing circuitry to sample the signal waveform induced on the cathode. The cathode waveform acquired with the HPWF circuitry offers excellent spatial resolution, energy resolution and depth of interaction (DOI) information, even with the presence of excessive charge-sharing/charge-loss between the small anode pixels. The HPWF CdTe detector is designed and constructed with a minimum amount of ferromagnetic materials, to ensure the MR-compatibility. To achieve sub-500?m imaging resolution, two special designed SPECT apertures have been constructed with different pinhole sizes of 300?m and 500?m respectively. It has 40 pinhole inserts that are made of cast platinum (90%)-iridium (10%) alloy, which provides the maximum stopping power and are compatible with MR scanners. The SPECT system is installed on a non-metal gantry constructed with 3-D printing using nylon powder material. This compact system can work as a "low-cost" desktop ultrahigh resolution SPECT system. It can also be directly operated inside an MR scanner. Accurate system geometrical calibration and corresponding image reconstruction methods for the MRC-SPECT system is developed. In order to account for the magnetic field induced distortion in the SPECT image, a comprehensive charge collection model inside strong magnetic field is adopted to produce high resolution SPECT image inside MR scanner.

Present assessment of myocardial viability by nuclear imaging.

PubMed

Saha, G B; MacIntyre, W J; Brunken, R C; Go, R T; Raja, S; Wong, C O; Chen, E Q

1996-10-01

Prospective delineation of viable from nonviable myocardium in patients with coronary artery disease in an important factor in deciding whether a patient should be revascularized or treated medically. Two common techniques--single-photon emission computed tomography (SPECT) and positron-emission computed tomography (PET)--are used in nuclear medicine using various radiopharmaceuticals for the detection of myocardial viability in patients. Thallium-201 (201Tl) and technetium-99m (99mTc)-sestamibi are the common radiopharmaceuticals used in different protocols using SPECT, whereas fluoride-18 (18F)-fluorodeoxyglucose (FDG) and rubidium-82 (82Rb) are most widely used in PET. The SPECT protocols involve stress/redistribution, stress/redistribution/reinjection, and rest/redistribution imaging techniques. Many studies have compared the results of 201Tl and (99mTc)-sestamibi SPECT with those of FDG PET; in some studies, concordant results have been found between delayed thallium and FDG results, indicating that 201Tl, although considered a perfusion agent, shows myocardial viability. Discordant results in a number of studies have been found between sestamibi and FDG, suggesting that the efficacy of sestamibi as a viability marker has yet to be established. Radiolabeled fatty acids such as iodine-123 (123I)-para-iodophenylpentadecanoic acid and carbon-11 (11C)-palmitic acid have been used for the assessment of myocardial viability with limited success. 11C-labeled acetate is a good marker of oxidative metabolism in the heart and has been used to predict the reversibility of wall motion abnormalities. (18F)-FDG is considered the marker of choice for myocardial viability, although variable results are obtained under different physiological conditions. Detection of myocardial viability can be greatly improved by developing new equipment and radiopharmaceuticals of better quality.

Evaluation of (99m)Tc-HYNIC-TMTP1 as a tumor-homing imaging agent targeting metastasis with SPECT.

PubMed

Li, Fei; Cheng, Teng; Dong, Qingjian; Wei, Rui; Zhang, Zhenzhong; Luo, Danfeng; Ma, Xiangyi; Wang, Shixuan; Gao, Qinglei; Ma, Ding; Zhu, Xiaohua; Xi, Ling

2015-03-01

TMTP1 (NVVRQ) is a novel tumor-homing peptide, which specifically targets tumor metastases, even at the early stage of occult metastasis foci. Fusing TMTP1 to therapeutic peptides or proteins can increase its anti-cancer efficacy both in vivo and in vitro. Here, we labeled TMTP1 with (99m)Tc to evaluate its targeting properties in an ovarian cancer xenograft tumor mouse model and a gastric cancer xenograft mouse model. The invasion ability of SKOV3 and highly metastatic SKOV3.ip cell lines were performed by the Transwell Invasion Assays, and then Rhodamine-TMTP1 was used to detect its affinity to these two cells. Using the co-ligand ethylenediamine-N, N'-diacetic acid (EDDA) and the bifunctional chelator 6-hydrazinonicotinic acid (HYNIC), the TMTP1 peptide was labeled with (99m)Tc. A cell-binding assay was performed by incubating cancer cells with (99m)Tc-HYNIC-TMTP1 with or without an excess dose of cold HYNIC-TMTP1. To evaluate the probe in vivo, nude mice bearing SKOV3, SKOV3.ip and MNK-45 tumor cells were established and subjected to SPECT imaging after injection with (99m)Tc-HYNIC-TMTP1. Ex vivo γ-counting of dissected tissues from the mice was used to evaluate its biodistribution. (99m)Tc-HYNIC-TMTP1 was successfully synthesized. The radiotracer also exhibited high hydrophilicity and excellent stability in vitro and in vivo. It has strong affinity to highly metastatic cancer cell lines but not to poorly metastatic cell lines. After mice were injected with (99m)Tc-HYNIC-TMTP1, non-invasive SPECT imaging detected SKOV3.ip and MNK-45 xenograft tumors but not SKOV3 xenograft tumors. This result can be inhibited by excess HYNIC-TMTP1. The uptake of (99m)Tc-HYNIC-TMTP1 in SKOV3.ip xenograft tumors was 0.182±0.017% ID/g at 2h p.i. with high renal uptake (74.32±15.05% ID/g at 2h p.i.). (99m)Tc-HYNIC-TMTP1 biodistribution and SPECT imaging demonstrated its ability to target highly metastatic tumors. Therefore, metastasis can be non-invasively investigated by SPECT imaging using (99m)Tc-HYNIC-TMTP1. Meanwhile, this radiotracer has some shortages in the low % ID/g of tumors and high accumulation in the kidney. Copyright © 2014 Elsevier Inc. All rights reserved.

99mTc-MDM Brain SPECT for the Detection of Recurrent/Remnant Glioma-Comparison With ceMRI and 18F-FLT PET Imaging: Initial Results.

PubMed

Singh, Baljinder; Kumar, Narendra; Sharma, Sarika; Watts, Ankit; Hazari, Puja P; Rani, Nisha; Vyas, Sameer; Anish, Bhattacharya; Mishra, Anil K

2015-10-01

To evaluate the diagnostic use of an indigenously developed single vial ready to label (with Tc) kit preparation of bis-methionine-DTPA (Tc-MDM) for the detection of recurrent/residual glioma. We prospectively studied 32 patients (21 male and 11 female subjects aged 43.0±16.0 years) with clinical suspicion of postoperative recurrent/residual glioma. After radical radiotherapy (54.0-60.0 Gy) with or without concurrent temozolomide as indicated, Tc-MDM SPECT and ceMRI of the brain was performed in all the patients and F-FLT-PET imaging in 16 of 32 patients. MDM SPECT and ceMRI findings were concordant in 28 patients (15 positive and 13 negative). The findings were discordant in the remaining 5 patients, with positive ceMRI and negative MDM-SPECT in 2 patients and negative ceMRI and positive MDM-SPECT in 3 patients. Tc-MDM-SPECT, F-FLT PET, and ceMRI scan findings were positive in 9 of 16 and negative in 5 of 16 patients. In the remaining 2 of 16 patients, both F-FLT-PET and Tc-MDM-SPECT were positive, but ceMRI was negative. Sensitivity, specificity, PPV, NPV, and DA of Tc-MDM-SPECT for diagnosing recurrent/residual glioma were 88.24%, 81.25%, 83.3%, 86.7%, and 84.8%, respectively. The diagnostic accuracy of Tc-bis-methionine (MDM)-SPECT imaging was comparable with that of ceMRI and F-FLT-PET and may be useful in the management of glioma patients in the postsurgical follow-up period. This imaging technique may be of special interest in peripheral hospitals/developing countries lacking access to expensive PET/cyclotron technology. However, comparison with the existing "gold standard" PET tracers, especially with C-11-methionine-PET imaging and histopathological correlation, is warranted in a large cohort of glioma patients through multicentric studies.

Comparison of ( sup 99m Tc)HMPAO SPECT with ( sup 18 F)fluoromethane PET in cerebrovascular disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heiss, W.D.; Herholz, K.; Podreka, I.

1990-09-01

Positron emission tomography (PET) of (18F)fluoromethane (FM) and single-photon emission tomography (SPECT) of (99mTc)hexamethylpropyleneamine oxime (HMPAO) were performed under identical conditions within 2 h in 22 patients suffering from cerebrovascular disease (8 ischemic infarction, 2 intracerebral hemorrhages, 7 transient ischemic attacks, and 5 multi-infarct syndrome). While gross pathological changes could be seen in the images of either procedure, focal abnormalities corresponding to transient ischemic deficits or to lesions in multi-infarct syndrome and areas of functional deactivation were sometimes missed on SPECT images. Overall, HMPAO SPECT images showed less contrast between high and low activity regions than the FM PET images,more » and differences between lesions and contralateral regions were less pronounced (6.4 vs 13.3% difference). Regional cerebral blood flow (rCBF) was calculated from FM PET studies in 14 large territorial regions and the pathological lesion, and the regional values relative to mean flow were compared to the relative HMPAO uptake in an identical set of regions defined on the SPECT images. Among individual patients, the Spearman rank-correlation coefficient between relative rCBF and HMPAO uptake varied between 0.48 and 0.89, with a mean of 0.70. While an underestimation of high flow with SPECT--which was demonstrated in a curvilinear relationship between all relative regional PET and SPECT values--could be corrected by linearization taking into account HMPAO efflux from the brain before metabolic trapping, correspondence of SPECT data with PET rCBF values was not improved since this procedure also increased the variance in high flow areas. In the cerebellum, however, a high HMPAO uptake in SPECT always overestimated CBF in relation to forebrain values; this finding might be due to high capillary density in the cerebellum.« less

Affordable CZT SPECT with dose-time minimization (Conference Presentation)

NASA Astrophysics Data System (ADS)

Hugg, James W.; Harris, Brian W.; Radley, Ian

2017-03-01

PURPOSE Pixelated CdZnTe (CZT) detector arrays are used in molecular imaging applications that can enable precision medicine, including small-animal SPECT, cardiac SPECT, molecular breast imaging (MBI), and general purpose SPECT. The interplay of gamma camera, collimator, gantry motion, and image reconstruction determines image quality and dose-time-FOV tradeoffs. Both dose and exam time can be minimized without compromising diagnostic content. METHODS Integration of pixelated CZT detectors with advanced ASICs and readout electronics improves system performance. Because historically CZT was expensive, the first clinical applications were limited to small FOV. Radiation doses were initially high and exam times long. Advances have significantly improved efficiency of CZT-based molecular imaging systems and the cost has steadily declined. We have built a general purpose SPECT system using our 40 cm x 53 cm CZT gamma camera with 2 mm pixel pitch and characterized system performance. RESULTS Compared to NaI scintillator gamma cameras: intrinsic spatial resolution improved from 3.8 mm to 2.0 mm; energy resolution improved from 9.8% to <4 % at 140 keV; maximum count rate is <1.5 times higher; non-detection camera edges are reduced 3-fold. Scattered photons are greatly reduced in the photopeak energy window; image contrast is improved; and the optimal FOV is increased to the entire camera area. CONCLUSION Continual improvements in CZT detector arrays for molecular imaging, coupled with optimal collimator and image reconstruction, result in minimized dose and exam time. With CZT cost improving, affordable whole-body CZT general purpose SPECT is expected to enable precision medicine applications.

Molecular Platform for Design and Synthesis of Targeted Dual-Modality Imaging Probes

PubMed Central

2015-01-01

We report a versatile dendritic structure based platform for construction of targeted dual-modality imaging probes. The platform contains multiple copies of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) branching out from a 1,4,7-triazacyclononane-N,N′,N″-triacetic acid (NOTA) core. The specific coordination chemistries of the NOTA and DOTA moieties offer specific loading of 68/67Ga3+ and Gd3+, respectively, into a common molecular scaffold. The platform also contains three amino groups which can potentiate targeted dual-modality imaging of PET/MRI or SPECT/MRI (PET: positron emission tomography; SPECT: single photon emission computed tomography; MRI: magnetic resonance imaging) when further functionalized by targeting vectors of interest. To validate this design concept, a bimetallic complex was synthesized with six peripheral Gd-DOTA units and one Ga-NOTA core at the center, whose ion T1 relaxivity per gadolinium atom was measured to be 15.99 mM–1 s–1 at 20 MHz. Further, the bimetallic agent demonstrated its anticipated in vivo stability, tissue distribution, and pharmacokinetic profile when labeled with 67Ga. When conjugated with a model targeting peptide sequence, the trivalent construct was able to visualize tumors in a mouse xenograft model by both PET and MRI via a single dose injection. PMID:25615011

Slow-rotation dynamic SPECT with a temporal second derivative constraint.

PubMed

Humphries, T; Celler, A; Trummer, M

2011-08-01

Dynamic tracer behavior in the human body arises as a result of continuous physiological processes. Hence, the change in tracer concentration within a region of interest (ROI) should follow a smooth curve. The authors propose a modification to an existing slow-rotation dynamic SPECT reconstruction algorithm (dSPECT) with the goal of improving the smoothness of time activity curves (TACs) and other properties of the reconstructed image. The new method, denoted d2EM, imposes a constraint on the second derivative (concavity) of the TAC in every voxel of the reconstructed image, allowing it to change sign at most once. Further constraints are enforced to prevent other nonphysical behaviors from arising. The new method is compared with dSPECT using digital phantom simulations and experimental dynamic 99mTc -DTPA renal SPECT data, to assess any improvement in image quality. In both phantom simulations and healthy volunteer experiments, the d2EM method provides smoother TACs than dSPECT, with more consistent shapes in regions with dynamic behavior. Magnitudes of TACs within an ROI still vary noticeably in both dSPECT and d2EM images, but also in images produced using an OSEM approach that reconstructs each time frame individually, based on much more complete projection data. TACs produced by averaging over a region are similar using either method, even for small ROIs. Results for experimental renal data show expected behavior in images produced by both methods, with d2EM providing somewhat smoother mean TACs and more consistent TAC shapes. The d2EM method is successful in improving the smoothness of time activity curves obtained from the reconstruction, as well as improving consistency of TAC shapes within ROIs.

Performance index: A method for quantitative evaluation of filters used in clinical SPECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Contino, J.; Touya, J.J.; Corbus, H.F.

1984-01-01

The purpose of this study was to design a method for optimal filter selection during the reconstruction of clinical SPECT images. Hamming, Bartlett, Parzen and Butterworth filters were evaluated at different cutoff frequencies when applied to reconstruction of the Jaszczak phantom and liver SPECTs. The phantom filled with 6 mCi of Tc-99m was imaged following 4 different protocols which varied in matrix sizes (128 x 128 or 64 x 64) and in number of steps (128 or 64). Total imaging time in the 4 protocols was 24 minutes. A total of 160 reconstructions were analyzed. Liver SPECTs from 2 patientsmore » with small metastatic lesions from colon Ca were similarly studied. An ECT Performance Index (ECT PI) was defined as the product of the contrast efficiency function (ECT C) and uniformity (ECT U). ECT C as a function of the radius was measured following Rollo's approach. ECT U was measured as the ratio between min. and max. counts per pixel in a known uniform region. ECT PI was computed on a slice through the void spheres region of the phantom. In liver SPECTs the ECT U was measured over the spleen. The most favorable ECT PI (0.35, radius 7.9 mm) was obtained with images in 128 x 128 matrices, 128 steps, processed with a Butterworth cutoff frequency of 0.19, filter order 4. When images were acquired in 64 x 64 matrices using 64 steps the ECT PI was lower and influenced to a lesser degree by both choice of filter and cutoff frequency. Results in the two liver SPECT examinations were parallel to those found in the phantom studies confirming the clinical usefulness of the ECT PI in the evaluation of filters for reconstruction of SPECT images.« less

A patient with type I CD36 deficiency whose myocardium accumulated 123I-BMIPP after 4 years.

PubMed

Ito, K; Sugihara, H; Tanabe, T; Zen, K; Hikosaka, T; Adachi, Y; Katoh, S; Azuma, A; Nakagawa, M

2001-06-01

A 73-year-old man with aortic regurgitation was examined by 123I-alpha-methyl-p-iodophenylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) in 1995. Myocardial accumulation was not evident on either the early or the delayed image obtained 15 minutes and 3 hours, respectively, after injecting 123I-BMIPP. Flow cytometric analysis of CD36 expression in monocytes and platelets identified a type I CD36 deficiency. The patient was hospitalized for severe heart failure in 1999. Upon admission, the cardiothoracic ratio on chest X-rays was 73%, and the left ventricular end-diastolic diameter on echocardiograms was enlarged to 77 mm. On the second day, we performed 123I-BMIPP myocardial SPECT. Myocardial accumulation was evident in the delayed, but not in the early image. We repeated 123I-BMIPP myocardial SPECT on the 10th day after admission. Myocardial accumulation was evident on both early and delayed images. 99mTc-tetrofosmin myocardial SPECT was immediately performed after 123I-BMIPP myocardial SPECT to distinguish myocardial from pooling images in the left ventricle, but, because the images from both 99Tc-tetrofosmin and 123I-BMIPP myocardial SPECT were idential, we considered that the 123I-BMIPP myocardial SPECT images reflected the actual myocardial condition. The CD36 molecule transports long-chain fatty acid (LCFA) on the myocardial membrane, but 123I-BMIPP scintigraphy does not show any myocardial accumulation in patients with type I CD36 deficiency, indicating that myocardial LCFA uptake occurs through CD36 on the human myocardial membrane. Even though our patient had type I CD36 deficiency, BMIPP was uptaken by the myocardium during heart failure, suggesting a variant pathway on the human myocardial membrane for LCFA uptake.

SU-C-9A-05: A Medical Physics Approach to the Evaluation of a New Anti-Reflux Catheter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasciak, A; McElmurray, J

2014-06-01

Purpose: The Surefire Infusion System (SIS) is a coaxial microcatheter system with a pliant expanding tip designed to limit retrograde flow of administered intra-arterial embolic agents and resultant non-target embolization (NTE). A recent study suggests that the SIS may achieve relative arterial hypotension downstream to the catheter tip when compared to an end-hole catheter, potentially altering microsphere distribution. We have used a physics based approach to evaluate particulate distribution using both the SIS and standard end-hole microcatheter via a two-step same-day injection of Tc-99m MAA as a microsphere surrogate. Methods: Informed patient consent and IRB approval were obtained. Four patientsmore » with primary or secondary liver cancer underwent two sequential low-particulate infusions of Tc-99m MAA on the same day using both the SIS and a conventional end-hole catheter. Radiopharmaceutical dosages of approximately 1:8 were utilized in the first infusion relative to the second to eliminate the effect of residual activity on the images acquired after each step. SPECT imaging was obtained following each infusion, and MAA distribution was analyzed and compared. Archived fluoroscopic images confirmed near-identical catheter position for both infusions. Results: SPECT images from all four patients demonstrate qualitatively increased penetration of MAA distal to the site of infusion using the SIS when compared to a standard end-hole catheter. Quantitative evaluations corroborate these findings with some distal regions receiving between 33% to more than 200% greater relative activity when SIS was used. No appreciable NTE was identified in either patient subset. Conclusion: These preliminary data demonstrate the validity of this dual-infusion technique. Both qualitative and quantitative assessment of SPECT images and comparison with baseline contrast enhanced CT and PET/CT images indicate an improvement in MAA penetration into the target lesion with the SIS. However, the degree of improvement is highly dependent on tumor type and size. Financial support provided by Surefire Medical.« less

Perfluorocarbon Nanoparticles:. A Theranostic Platform Technology

NASA Astrophysics Data System (ADS)

Lanza, Gregory M.; Winter, Patrick M.; Caruthers, Shelton D.; Hughes, Michael S.; Hu, Grace; Pan, Dipanjan; Schmieder, Anne H.; Pham, Christine; Wickline, Samuel A.

2013-09-01

Nanomedicine clearly offers unique tools to address intractable medical problems in cancer and cardiovascular disease from entirely new perspectives. Among the theranostic options emerging in this new wave of biotechnology development, the perfluorocarbon nanoparticles have shown robust potential in vivo for diagnosing, characterizing, treating and following proliferating cancers, progressive atherosclerosis, rheumatoid arthritis and much more. These molecular imaging agents have been demonstrated for use with ultrasound, MRI, CT, and SPECT/CT. Moreover, the synergism of imaging for confirmation of therapeutic delivery, for dosimetry, and for noninvasively following early treatment responses is discussed. Image-guided drug delivery based on nanotechnology is emerging as a powerful clinical opportunity, and PFC nanoparticles are among the leading technologies reaching clinical testing today with this potential.

Technetium-99m-HMPAO labeled leukocyte single photon emission computerized tomography (SPECT) for assessing Crohn's disease extent and intestinal infiltration.

PubMed

Biancone, L; Schillaci, O; Capoccetti, F; Bozzi, R M; Fina, D; Petruzziello, C; Geremia, A; Simonetti, G; Pallone, F

2005-02-01

Scintigraphy using radiolabeled leukocytes is a useful technique for assessing intestinal infiltration in Crohn's disease (CD). However, limits of planar images include overlapping activity in other organs and low specificity. To investigate the usefulness of (99m)Tc-HMPAO (hexametyl propylene amine oxime) labeled leukocyte single photon emission computerized tomography (SPECT) for assessing CD lesions, in comparison with planar images. Twenty-two inflammatory bowel disease patients (19 CD; 2 ulcerative colitis, UC; 1 ileal pouch) assessed by conventional endoscopy or radiology were enrolled. Leukocytes were labeled with (99m)Tc-HMPAO. SPECT images were acquired at 2 h and planar images at 30 min and 2 h. Bowel uptake was quantitated in nine regions (score 0-3). Both SPECT and planar images detected a negative scintigraphy (score 0) in the UC patient with no pouchitis and a positive scintigraphy (score 1-3) in the 21 patients showing active inflammation by conventional techniques. SPECT showed a higher global score than planar images (0.71 +/- 0.09 vs 0.30 +/- 0.05; p < 0.001), and in particular in the right iliac fossa (p= 0.003), right and left flank (p < 0.001; p= 0.02), hypogastrium (p= 0.002), and mesogastrium (p < 0.001). SPECT provided a better visualization and a higher uptake than planar images in patients with ileal and ileocolonic CD (6.45 +/- 0.82 vs 2.8 +/- 0.55, p < 0.001; 5.5 +/- 1.6 vs 2.6 +/- 0.7, p= 0.03), and with perianal CD (6.6 +/- 1.6 vs 3.4 +/- 1.2; p= 0.03). (99m)Tc-HMPAO labeled leukocyte SPECT provides a more detailed visualization of CD lesions than planar images. This technique may better discriminate between intestinal and bone marrow uptake, thus being useful for assessing CD lesions within the pelvis, including perianal disease.

Which metabolic imaging, besides bone scan with 99mTc-phosphonates, for detecting and evaluating bone metastases in prostatic cancer patients? An open discussion.

PubMed

Bombardieri, E; Setti, L; Kirienko, M; Antunovic, L; Guglielmo, P; Ciocia, G

2015-12-01

Prostate cancer bone metastases occur frequently in advanced cancer and this is matter of particular attention, due to the great impact on patient's management and considering that a lot of new emerging therapeutic options have been recently introduced. Imaging bone metastases is essential to localize lesions, to establish their size and number, to study characteristics and changes during therapy. Besides radiological imaging, nuclear medicine modalities can image their features and offer additional information about their metabolic behaviour. They can be classified according to physical characteristics, type of detection, mechanism of uptake, availability for daily use. The physiopathology of metastases formation and the mechanisms of tracer uptake are essential to understand the interpretation of nuclear medicine images. Therefore, radiopharmaceuticals for bone metastases can be classified in agents targeting bone (99mTc-phosphonates, 18F-fluoride) and those targeting prostatic cancer cells (18F-fluoromethylcholine, 11C-choline, 18F-fluorodeoxyglucose). The modalities using the first group of tracers are planar bone scan, SPECT or SPECT/CT with 99mTc-diphosphonates, and 18F-fluoride PET/CT, while the modalities using the second group include 18F/11C-choline derivatives PET/CT, 18F-FDG PET/CT and PET/CT scans with several other radiopharmaceuticals described in the literature, such as 18F/11C-acetate derivatives, 18F-fluoro-5α-dihydrotestosterone (FDHT), 18F-anti-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC), 18F-2'-fluoro-5-methyl-1-β-D-arabinofuranosyluracil (FMAU) and 68Ga-labeled-prostate specific membrane antigen (PMSA) PET/TC. However, since data on clinical validation for these last novel modalities are not conclusive and/or are not still sufficient in number, at present they can be still considered as promising tools under evaluation. The present paper considers the nuclear modalities today available for the clinical routine. This overview wants to discuss the opportunities and the drawbacks of these current diagnostic tests in a scenario where planar scintigraphy and/or SPECT with phosphonates, is the only metabolic imaging recommended by the most important Guidelines of the Scientific Societies dealing with prostate cancer. Other nuclear medicine modalities are in very few cases just cited, never recommended except in rare situations. Is there space for agents other than 99mTc-phosphonates to image bone lesions from prostate cancer?

Diagnostic utility of 99mTc-EDDA-tricine-HYNIC-Tyr3-octreotate SPECT for differentiation of active from inactive pulmonary tuberculosis.

PubMed

Ahmadihosseini, Hossein; Abedi, Javad; Ghodsi Rad, Mohammad A; Zakavi, Seyed R; Knoll, Peter; Mirzaei, Siroos; Sadeghi, Ramin

2014-12-01

The current study was performed to evaluate the impact of Tc-EDDA-tricine-HYNIC-Tyr-octreotate in the differentiation of active from inactive pulmonary tuberculosis lesions. Ten consecutive patients (six male and four female, age range 24-83 years) with proven pulmonary tuberculosis (with a positive smear or culture) were enrolled in the study. At 120 min after injection of 740 MBq of Tc-EDDA-tricine-HYNIC-Tyr-octreotate, planar and single-photon emission computed tomography (SPECT) images of the thorax were taken. A semiquantitative evaluation of lesion and nonlesion areas was performed. The scan was repeated following the same protocol after standard treatment for tuberculosis after a negative sputum culture. Semiquantitative evaluation of the lesions showed a statistically significant higher uptake before treatment in both planar and SPECT images (P=0.005 and 0.007, respectively). Lesion-to-nonlesion ratios were also higher in the pretreatment sets on both planar and SPECT images (1.4±0.2 vs. 1.19±0.15, P=0.001, for planar images and 2.32±0.55 vs. 1.32±0.32, P=0.0001, for SPECT images). Tc-EDDA-tricine-HYNIC-Tyr-octreotate scintigraphy may help to differentiate between active and inactive pulmonary tuberculosis. SPECT imaging and semiquantitative evaluation are indispensable for increasing the diagnostic yield of this method. Larger studies are needed to corroborate our results.

SPECT/CT with radiolabeled somatostatin analogues in the evaluation of systemic granulomatous infections.

PubMed

Monteiro, Paulo Henrique Silva; de Souza, Thiago Ferreira; Moretti, Maria Luiza; Resende, Mariangela Ribeiro; Mengatti, Jair; de Lima, Mariana da Cunha Lopes; Santos, Allan Oliveira; Ramos, Celso Darío

2017-01-01

To evaluate SPECT/CT with radiolabeled somatostatin analogues (RSAs) in systemic granulomatous infections in comparison with gallium-67 ( 67 Ga) citrate scintigraphy. We studied 28 patients with active systemic granulomatous infections, including tuberculosis, paracoccidioidomycosis, pneumocystosis, cryptococcosis, aspergillosis, leishmaniasis, infectious vasculitis, and an unspecified opportunistic infection. Of the 28 patients, 23 had started specific treatment before the study outset. All patients underwent whole-body SPECT/CT imaging: 7 after injection of 99m Tc-EDDA-HYNIC-TOC, and 21 after injection of 111 In-DTPA-octreotide. All patients also underwent 67 Ga citrate imaging, except for one patient who died before the 67 Ga was available. In 20 of the 27 patients who underwent imaging with both tracers, 27 sites of active disease were detected by 67 Ga citrate imaging and by SPECT/CT with an RSA. Both tracers had negative results in the other 7 patients. RSA uptake was visually lower than 67 Ga uptake in 11 of the 20 patients with positive images and similar to 67 Ga uptake in the other 9 patients. The only patient who did not undergo 67 Ga scintigraphy underwent 99m Tc-EDDA-HYNIC-TOC SPECT/CT-guided biopsy of a lung cavity with focal RSA uptake, which turned to be positive for aspergillosis. SPECT/CT with 99m Tc-EDDA-HYNIC-TOC or 111 In-DTPA-octreotide seems to be a good alternative to 67 Ga citrate imaging for the evaluation of patients with systemic granulomatous disease.

Enhanced perfusion defect clarity and inhomogeneity in smokers' lungs with deep-inspiratory breath-hold perfusion SPECT images.

PubMed

Suga, Kazuyoshi; Yasuhiko, Kawakami; Iwanaga, Hideyuki; Hayashi, Norio; Yamashita, Tomio; Matsunaga, Naofumi

2005-09-01

Deep-inspiratory breath-hold (DIBrH) Tc-99m-macroaggregated albumin (MAA) SPECT images were developed to accurately evaluate perfusion impairment in smokers' lungs. DIBrH SPECT was performed in 28 smokers with or without low attenuation areas (LAA) on CT images, using a triple-headed SPECT system and a laser light respiratory tracking device. DIBrH SPECT images were reconstructed from every 4 degrees projection of five adequate 360 degrees projection data sets with almost the same respiratory dimension at 20 sec DIBrH. Perfusion defect clarity was assessed by the lesion (defect)-to-contralateral normal lung count ratios (L/N ratios). Perfusion inhomogeneity was assessed by the coefficient of variation (CV) values of pixel counts and correlated with the diffusing capacity of the lungs for carbon monoxide/alveolar volume (DLCO/VA) ratios. The results were compared with those on conventional images. Five DIBrH projection data sets with minimal dimension differences of 2.9+/-0.6 mm were obtained in all subjects. DIBrH images enhanced perfusion defects compared with conventional images, with significantly higher L/N ratios (P<0.0001), and detected a total of 109 (26.9%) additional detects (513 vs. 404), with excellent inter-observer agreement (kappa value of 0.816). CV values in the smokers' lungs on DIBrH images were also significantly higher compared with those on conventional images (0.31+/-0.10 vs. 0.19+/-0.06, P<0.0001). CV values in smokers on DIBrH images showed a significantly closer correlation with DLCO/VA ratios compared with conventional images (R = 0.872, P<0.0001 vs. R=0.499, P<0.01). By reducing adverse effect of respiratory motion, DIBrH SPECT images enhance perfusion defect clarity and inhomogeneity, and provide more accurate assessment of impaired perfusion in smokers' lungs compared with conventional images.

Relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism: assessment with breath-hold SPECT-CT pulmonary angiography fusion images.

PubMed

Suga, Kazuyoshi; Yasuhiko, Kawakami; Iwanaga, Hideyuki; Tokuda, Osamu; Matsunaga, Naofumi

2008-09-01

The relation between lung perfusion defects and intravascular clots in acute pulmonary thromboembolism (PTE) was comprehensively assessed on deep-inspiratory breath-hold (DIBrH) perfusion SPECT-computed tomographic pulmonary angiography (CTPA) fusion images. Subjects were 34 acute PTE patients, who had successfully performed DIBrH perfusion SPECT using a dual-headed SPECT and a respiratory tracking system. Automated DIBrH SPECT-CTPA fusion images were used to assess the relation between lung perfusion defects and intravascular clots detected by CTPA. DIBrH SPECT visualized 175 lobar/segmental or subsegmental defects in 34 patients, and CTPA visualized 61 intravascular clots at variable locations in 30 (88%) patients, but no clots in four (12%) patients. In 30 patients with clots, the fusion images confirmed that 69 (41%) perfusion defects (20 segmental, 45 subsegmental and 4 lobar defects) of total 166 defects were located in lung territories without clots, although the remaining 97 (58%) defects were located in lung territories with clots. Perfusion defect was absent in lung territories with clots (one lobar branch and three segmental branches) in four (12%) of these patients. In four patients without clots, nine perfusion defects including four segmental ones were present. Because of unexpected dissociation between intravascular clots and lung perfusion defects, the present fusion images will be a useful adjunct to CTPA in the diagnosis of acute PTE.

The value of 99mTc-MAA SPECT/CT for lung shunt estimation in 90Y radioembolization: a phantom and patient study.

PubMed

Allred, Jonathan D; Niedbala, Jeremy; Mikell, Justin K; Owen, Dawn; Frey, Kirk A; Dewaraja, Yuni K

2018-06-15

A major toxicity concern in radioembolization therapy of hepatic malignancies is radiation-induced pneumonitis and sclerosis due to hepatopulmonary shunting of 90 Y microspheres. Currently, 99m Tc macroaggregated albumin ( 99m Tc-MAA) imaging is used to estimate the lung shunt fraction (LSF) prior to treatment. The aim of this study was to evaluate the accuracy/precision of LSF estimated from 99m Tc planar and SPECT/CT phantom imaging, and within this context, to compare the corresponding LSF and lung-absorbed dose values from 99m Tc-MAA patient studies. Additionally, LSFs from pre- and post-therapy imaging were compared. A liver/lung torso phantom filled with 99m Tc to achieve three lung shunt values was scanned by planar and SPECT/CT imaging with repeat acquisitions to assess accuracy and precision. To facilitate processing of patient data, a workflow that relies on SPECT and CT-based auto-contouring to define liver and lung volumes for the LSF calculation was implemented. Planar imaging-based LSF estimates for 40 patients, obtained from their medical records, were retrospectively compared with SPECT/CT imaging-based calculations with attenuation and scatter correction. Additionally, in a subset of 20 patients, the pre-therapy estimates were compared with 90 Y PET/CT-based measurements. In the phantom study, improved accuracy in LSF estimation was achieved using SPECT/CT with attenuation and scatter correction (within 13% of the true value) compared with planar imaging (up to 44% overestimation). The results in patients showed a similar trend with planar imaging significantly overestimating LSF compared to SPECT/CT. There was no correlation between lung shunt estimates and the delay between 99m Tc-MAA administration and scanning, but off-target extra hepatic uptake tended to be more likely in patients with a longer delay. The mean lung absorbed dose predictions for the 28 patients who underwent therapy was 9.3 Gy (range 1.3-29.4) for planar imaging and 3.2 Gy (range 0.4-13.4) for SPECT/CT. For the patients with post-therapy imaging, the mean LSF from 90 Y PET/CT was 1.0%, (range 0.3-2.8). This value was not significantly different from the mean LSF estimate from 99m Tc-MAA SPECT/CT (mean 1.0%, range 0.4-1.6; p = 0.968), but was significantly lower than the mean LSF estimate based on planar imaging (mean 4.1%, range 1.2-15.0; p = 0.0002). The improved accuracy demonstrated by the phantom study, agreement with 90 Y PET/CT in patient studies, and the practicality of using auto-contouring for liver/lung definition suggests that 99m Tc-MAA SPECT/CT with scatter and attenuation corrections should be used for lung shunt estimation prior to radioembolization.

Initial In Vivo Quantification of Tc-99m Sestamibi Uptake as a Function of Tissue Type in Healthy Breasts Using Dedicated Breast SPECT-CT

PubMed Central

Mann, Steve D.; Perez, Kristy L.; McCracken, Emily K. E.; Shah, Jainil P.; Wong, Terence Z.; Tornai, Martin P.

2012-01-01

A pilot study is underway to quantify in vivo the uptake and distribution of Tc-99m Sestamibi in subjects without previous history of breast cancer using a dedicated SPECT-CT breast imaging system. Subjects undergoing diagnostic parathyroid imaging studies were consented and imaged as part of this IRB-approved breast imaging study. For each of the seven subjects, one randomly selected breast was imaged prone-pendant using the dedicated, compact breast SPECT-CT system underneath the shielded patient support. Iteratively reconstructed and attenuation and/or scatter corrected images were coregistered; CT images were segmented into glandular and fatty tissue by three different methods; the average concentration of Sestamibi was determined from the SPECT data using the CT-based segmentation and previously established quantification techniques. Very minor differences between the segmentation methods were observed, and the results indicate an average image-based in vivo Sestamibi concentration of 0.10 ± 0.16 μCi/mL with no preferential uptake by glandular or fatty tissues. PMID:22956950

Investigation of dynamic SPECT measurements of the arterial input function in human subjects using simulation, phantom and human studies

NASA Astrophysics Data System (ADS)

Winant, Celeste D.; Aparici, Carina Mari; Zelnik, Yuval R.; Reutter, Bryan W.; Sitek, Arkadiusz; Bacharach, Stephen L.; Gullberg, Grant T.

2012-01-01

Computer simulations, a phantom study and a human study were performed to determine whether a slowly rotating single-photon computed emission tomography (SPECT) system could provide accurate arterial input functions for quantification of myocardial perfusion imaging using kinetic models. The errors induced by data inconsistency associated with imaging with slow camera rotation during tracer injection were evaluated with an approach called SPECT/P (dynamic SPECT from positron emission tomography (PET)) and SPECT/D (dynamic SPECT from database of SPECT phantom projections). SPECT/P simulated SPECT-like dynamic projections using reprojections of reconstructed dynamic 94Tc-methoxyisobutylisonitrile (94Tc-MIBI) PET images acquired in three human subjects (1 min infusion). This approach was used to evaluate the accuracy of estimating myocardial wash-in rate parameters K1 for rotation speeds providing 180° of projection data every 27 or 54 s. Blood input and myocardium tissue time-activity curves (TACs) were estimated using spatiotemporal splines. These were fit to a one-compartment perfusion model to obtain wash-in rate parameters K1. For the second method (SPECT/D), an anthropomorphic cardiac torso phantom was used to create real SPECT dynamic projection data of a tracer distribution derived from 94Tc-MIBI PET scans in the blood pool, myocardium, liver and background. This method introduced attenuation, collimation and scatter into the modeling of dynamic SPECT projections. Both approaches were used to evaluate the accuracy of estimating myocardial wash-in parameters for rotation speeds providing 180° of projection data every 27 and 54 s. Dynamic cardiac SPECT was also performed in a human subject at rest using a hybrid SPECT/CT scanner. Dynamic measurements of 99mTc-tetrofosmin in the myocardium were obtained using an infusion time of 2 min. Blood input, myocardium tissue and liver TACs were estimated using the same spatiotemporal splines. The spatiotemporal maximum-likelihood expectation-maximization (4D ML-EM) reconstructions gave more accurate reconstructions than did standard frame-by-frame static 3D ML-EM reconstructions. The SPECT/P results showed that 4D ML-EM reconstruction gave higher and more accurate estimates of K1 than did 3D ML-EM, yielding anywhere from a 44% underestimation to 24% overestimation for the three patients. The SPECT/D results showed that 4D ML-EM reconstruction gave an overestimation of 28% and 3D ML-EM gave an underestimation of 1% for K1. For the patient study the 4D ML-EM reconstruction provided continuous images as a function of time of the concentration in both ventricular cavities and myocardium during the 2 min infusion. It is demonstrated that a 2 min infusion with a two-headed SPECT system rotating 180° every 54 s can produce measurements of blood pool and myocardial TACs, though the SPECT simulation studies showed that one must sample at least every 30 s to capture a 1 min infusion input function.

Performance Evaluation and Quantitative Accuracy of Multipinhole NanoSPECT/CT Scanner for Theranostic Lu-177 Imaging

NASA Astrophysics Data System (ADS)

Gupta, Arun; Kim, Kyeong Yun; Hwang, Donghwi; Lee, Min Sun; Lee, Dong Soo; Lee, Jae Sung

2018-06-01

SPECT plays important role in peptide receptor targeted radionuclide therapy using theranostic radionuclides such as Lu-177 for the treatment of various cancers. However, SPECT studies must be quantitatively accurate because the reliable assessment of tumor uptake and tumor-to-normal tissue ratios can only be performed using quantitatively accurate images. Hence, it is important to evaluate performance parameters and quantitative accuracy of preclinical SPECT systems for therapeutic radioisotopes before conducting pre- and post-therapy SPECT imaging or dosimetry studies. In this study, we evaluated system performance and quantitative accuracy of NanoSPECT/CT scanner for Lu-177 imaging using point source and uniform phantom studies. We measured recovery coefficient, uniformity, spatial resolution, system sensitivity and calibration factor for mouse whole body standard aperture. We also performed the experiments using Tc-99m to compare the results with that of Lu-177. We found that the recovery coefficient of more than 70% for Lu-177 at the optimum noise level when nine iterations were used. The spatial resolutions of Lu-177 with and without adding uniform background was comparable to that of Tc-99m in axial, radial and tangential directions. System sensitivity measured for Lu-177 was almost three times less than that of Tc-99m.

A restraint-free small animal SPECT imaging system with motion tracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisenberger, A.G.; Gleason, S.S.; Goddard, J.

2005-06-01

We report on an approach toward the development of a high-resolution single photon emission computed tomography (SPECT) system to image the biodistribution of radiolabeled tracers such as Tc-99m and I-125 in unrestrained/unanesthetized mice. An infrared (IR)-based position tracking apparatus has been developed and integrated into a SPECT gantry. The tracking system is designed to measure the spatial position of a mouse's head at a rate of 10-15 frames per second with submillimeter accuracy. The high-resolution, gamma imaging detectors are based on pixellated NaI(Tl) crystal scintillator arrays, position-sensitive photomultiplier tubes, and novel readout circuitry requiring fewer analog-digital converter (ADC) channels whilemore » retaining high spatial resolution. Two SPECT gamma camera detector heads based upon position-sensitive photomultiplier tubes have been built and installed onto the gantry. The IR landmark-based pose measurement and tracking system is under development to provide animal position data during a SPECT scan. The animal position and orientation data acquired by the tracking system will be used for motion correction during the tomographic image reconstruction.« less

Acceptance test of a commercially available software for automatic image registration of computed tomography (CT), magnetic resonance imaging (MRI) and 99mTc-methoxyisobutylisonitrile (MIBI) single-photon emission computed tomography (SPECT) brain images.

PubMed

Loi, Gianfranco; Dominietto, Marco; Manfredda, Irene; Mones, Eleonora; Carriero, Alessandro; Inglese, Eugenio; Krengli, Marco; Brambilla, Marco

2008-09-01

This note describes a method to characterize the performances of image fusion software (Syntegra) with respect to accuracy and robustness. Computed tomography (CT), magnetic resonance imaging (MRI), and single-photon emission computed tomography (SPECT) studies were acquired from two phantoms and 10 patients. Image registration was performed independently by two couples composed of one radiotherapist and one physicist by means of superposition of anatomic landmarks. Each couple performed jointly and saved the registration. The two solutions were averaged to obtain the gold standard registration. A new set of estimators was defined to identify translation and rotation errors in the coordinate axes, independently from point position in image field of view (FOV). Algorithms evaluated were local correlation (LC) for CT-MRI, normalized mutual information (MI) for CT-MRI, and CT-SPECT registrations. To evaluate accuracy, estimator values were compared to limiting values for the algorithms employed, both in phantoms and in patients. To evaluate robustness, different alignments between images taken from a sample patient were produced and registration errors determined. LC algorithm resulted accurate in CT-MRI registrations in phantoms, but exceeded limiting values in 3 of 10 patients. MI algorithm resulted accurate in CT-MRI and CT-SPECT registrations in phantoms; limiting values were exceeded in one case in CT-MRI and never reached in CT-SPECT registrations. Thus, the evaluation of robustness was restricted to the algorithm of MI both for CT-MRI and CT-SPECT registrations. The algorithm of MI proved to be robust: limiting values were not exceeded with translation perturbations up to 2.5 cm, rotation perturbations up to 10 degrees and roto-translational perturbation up to 3 cm and 5 degrees.

Synthesis, Characterization, and Application of Core–Shell Co0.16Fe2.84O4@NaYF4(Yb, Er) and Fe3O4@NaYF4(Yb, Tm) Nanoparticle as Trimodal (MRI, PET/SPECT, and Optical) Imaging Agents

PubMed Central

2015-01-01

Multimodal nanoparticulate materials are described, offering magnetic, radionuclide, and fluorescent imaging capabilities to exploit the complementary advantages of magnetic resonance imaging (MRI), positron emission tomography/single-photon emission commuted tomography (PET/SPECT), and optical imaging. They comprise Fe3O4@NaYF4 core/shell nanoparticles (NPs) with different cation dopants in the shell or core, including Co0.16Fe2.84O4@NaYF4(Yb, Er) and Fe3O4@NaYF4(Yb, Tm). These NPs are stabilized by bisphosphonate polyethylene glycol conjugates (BP-PEG), and then show a high transverse relaxivity (r2) up to 326 mM–1 s–1 at 3T, a high affinity to [18F]-fluoride or radiometal-bisphosphonate conjugates (e.g., 64Cu and 99mTc), and fluorescent emissions from 500 to 800 nm under excitation at 980 nm. The biodistribution of intravenously administered particles determined by PET/MR imaging suggests that negatively charged Co0.16Fe2.84O4@NaYF4(Yb, Er)-BP-PEG (10K) NPs cleared from the blood pool more slowly than positively charged NPs Fe3O4@NaYF4(Yb, Tm)-BP-PEG (2K). Preliminary results in sentinel lymph node imaging in mice indicate the advantages of multimodal imaging. PMID:26172432

Lutetium oxyorthosilicate (LSO) intrinsic activity correction and minimal detectable target activity study for SPECT imaging with a LSO-based animal PET scanner

NASA Astrophysics Data System (ADS)

Yao, Rutao; Ma, Tianyu; Shao, Yiping

2008-08-01

This work is part of a feasibility study to develop SPECT imaging capability on a lutetium oxyorthosilicate (LSO) based animal PET system. The SPECT acquisition was enabled by inserting a collimator assembly inside the detector ring and acquiring data in singles mode. The same LSO detectors were used for both PET and SPECT imaging. The intrinsic radioactivity of 176Lu in the LSO crystals, however, contaminates the SPECT data, and can generate image artifacts and introduce quantification error. The objectives of this study were to evaluate the effectiveness of a LSO background subtraction method, and to estimate the minimal detectable target activity (MDTA) of image object for SPECT imaging. For LSO background correction, the LSO contribution in an image study was estimated based on a pre-measured long LSO background scan and subtracted prior to the image reconstruction. The MDTA was estimated in two ways. The empirical MDTA (eMDTA) was estimated from screening the tomographic images at different activity levels. The calculated MDTA (cMDTA) was estimated from using a formula based on applying a modified Currie equation on an average projection dataset. Two simulated and two experimental phantoms with different object activity distributions and levels were used in this study. The results showed that LSO background adds concentric ring artifacts to the reconstructed image, and the simple subtraction method can effectively remove these artifacts—the effect of the correction was more visible when the object activity level was near or above the eMDTA. For the four phantoms studied, the cMDTA was consistently about five times of the corresponding eMDTA. In summary, we implemented a simple LSO background subtraction method and demonstrated its effectiveness. The projection-based calculation formula yielded MDTA results that closely correlate with that obtained empirically and may have predicative value for imaging applications.

Applications of iQID cameras

NASA Astrophysics Data System (ADS)

Han, Ling; Miller, Brian W.; Barrett, Harrison H.; Barber, H. Bradford; Furenlid, Lars R.

2017-09-01

iQID is an intensified quantum imaging detector developed in the Center for Gamma-Ray Imaging (CGRI). Originally called BazookaSPECT, iQID was designed for high-resolution gamma-ray imaging and preclinical gamma-ray single-photon emission computed tomography (SPECT). With the use of a columnar scintillator, an image intensifier and modern CCD/CMOS sensors, iQID cameras features outstanding intrinsic spatial resolution. In recent years, many advances have been achieved that greatly boost the performance of iQID, broadening its applications to cover nuclear and particle imaging for preclinical, clinical and homeland security settings. This paper presents an overview of the recent advances of iQID technology and its applications in preclinical and clinical scintigraphy, preclinical SPECT, particle imaging (alpha, neutron, beta, and fission fragment), and digital autoradiography.

Automated three-dimensional quantification of myocardial perfusion and brain SPECT.

PubMed

Slomka, P J; Radau, P; Hurwitz, G A; Dey, D

2001-01-01

To allow automated and objective reading of nuclear medicine tomography, we have developed a set of tools for clinical analysis of myocardial perfusion tomography (PERFIT) and Brain SPECT/PET (BRASS). We exploit algorithms for image registration and use three-dimensional (3D) "normal models" for individual patient comparisons to composite datasets on a "voxel-by-voxel basis" in order to automatically determine the statistically significant abnormalities. A multistage, 3D iterative inter-subject registration of patient images to normal templates is applied, including automated masking of the external activity before final fit. In separate projects, the software has been applied to the analysis of myocardial perfusion SPECT, as well as brain SPECT and PET data. Automatic reading was consistent with visual analysis; it can be applied to the whole spectrum of clinical images, and aid physicians in the daily interpretation of tomographic nuclear medicine images.

Prospective Evaluation of (99m)Tc-sestamibi SPECT/CT for the Diagnosis of Renal Oncocytomas and Hybrid Oncocytic/Chromophobe Tumors.

PubMed

Gorin, Michael A; Rowe, Steven P; Baras, Alexander S; Solnes, Lilja B; Ball, Mark W; Pierorazio, Phillip M; Pavlovich, Christian P; Epstein, Jonathan I; Javadi, Mehrbod S; Allaf, Mohamad E

2016-03-01

Nuclear imaging offers a potential noninvasive means of determining the histology of renal tumors. The aim of this study was to evaluate the accuracy of technetium-99m ((99m)Tc)-sestamibi single-photon emission computed tomography/x-ray computed tomography (SPECT/CT) for the differentiation of oncocytomas and hybrid oncocytic/chromophobe tumors (HOCTs) from other renal tumor histologies. In total, 50 patients with a solid clinical T1 renal mass were imaged with (99m)Tc-sestamibi SPECT/CT prior to surgical resection. Preoperative SPECT/CT scans were reviewed by two blinded readers, and their results were compared with centrally reviewed surgical pathology data. Following surgery, 6 (12%) tumors were classified as renal oncocytomas and 2 (4%) as HOCTs. With the exception of 1 (2%) angiomyolipoma, all other tumors were renal cell carcinomas (82%). (99m)Tc-sestamibi SPECT/CT correctly identified 5 of 6 (83.3%) oncocytomas and 2 of 2 (100%) HOCTs, resulting in an overall sensitivity of 87.5% (95% confidence interval [CI], 47.4-99.7%). Only two tumors were falsely positive on SPECT/CT, resulting in a specificity of 95.2% (95% CI, 83.8-99.4%). In summary, (99m)Tc-sestamibi SPECT/CT is a promising imaging test for the noninvasive diagnosis of renal oncocytomas and HOCTs. We found that the imaging test (99m)Tc-sestamibi SPECT/CT can be used to accurately diagnose two types of benign kidney tumors. This test may be eventually used to help better evaluate patients diagnosed with a renal tumor. Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Molecular Imaging: Current Status and Emerging Strategies

PubMed Central

Pysz, Marybeth A.; Gambhir, Sanjiv S.; Willmann, Jürgen K.

2011-01-01

In vivo molecular imaging has a great potential to impact medicine by detecting diseases in early stages (screening), identifying extent of disease, selecting disease- and patient-specific therapeutic treatment (personalized medicine), applying a directed or targeted therapy, and measuring molecular-specific effects of treatment. Current clinical molecular imaging approaches primarily use PET- or SPECT-based techniques. In ongoing preclinical research novel molecular targets of different diseases are identified and, sophisticated and multifunctional contrast agents for imaging these molecular targets are developed along with new technologies and instrumentation for multimodality molecular imaging. Contrast-enhanced molecular ultrasound with molecularly-targeted contrast microbubbles is explored as a clinically translatable molecular imaging strategy for screening, diagnosing, and monitoring diseases at the molecular level. Optical imaging with fluorescent molecular probes and ultrasound imaging with molecularly-targeted microbubbles are attractive strategies since they provide real-time imaging, are relatively inexpensive, produce images with high spatial resolution, and do not involve exposure to ionizing irradiation. Raman spectroscopy/microscopy has emerged as a molecular optical imaging strategy for ultrasensitive detection of multiple biomolecules/biochemicals with both in vivo and ex vivo versatility. Photoacoustic imaging is a hybrid of optical and ultrasound modalities involving optically-excitable molecularly-targeted contrast agents and quantitative detection of resulting oscillatory contrast agent movement with ultrasound. Current preclinical findings and advances in instrumentation such as endoscopes and microcatheters suggest that these molecular imaging modalities have numerous clinical applications and will be translated into clinical use in the near future. PMID:20541650

Cardiac sarcoidosis demonstrated by Tl-201 and Ga-67 SPECT imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taki, J.; Nakajima, K.; Bunko, H.

1990-09-01

Ga-67 and Tl-201 SPECT was performed to evaluate cardiac sarcoidosis in a 15-year-old boy. Tl-201 SPECT imaging showed decreased uptake in the inferior to lateral wall and Ga-67 accumulation in the area of decreased Tl-201 uptake. These findings suggested cardiac sarcoidosis, and cardiac biopsy confirmed this diagnosis. After corticosteroid therapy, myocardial uptake of Ga-67 disappeared and myocardial TI-201 uptake became more homogeneous.

The Added Value of a Single-photon Emission Computed Tomography-Computed Tomography in Sentinel Lymph Node Mapping in Patients with Breast Cancer and Malignant Melanoma.

PubMed

Bennie, George; Vorster, Mariza; Buscombe, John; Sathekge, Mike

2015-01-01

Single-photon emission computed tomography-computed tomography (SPECT-CT) allows for physiological and anatomical co-registration in sentinel lymph node (SLN) mapping and offers additional benefits over conventional planar imaging. However, the clinical relevance when considering added costs and radiation burden of these reported benefits remains somewhat uncertain. This study aimed to evaluate the possible added value of SPECT-CT and intra-operative gamma-probe use over planar imaging alone in the South African setting. 80 patients with breast cancer or malignant melanoma underwent both planar and SPECT-CT imaging for SLN mapping. We assessed and compared the number of nodes detected on each study, false positive and negative findings, changes in surgical approach and or patient management. In all cases where a sentinel node was identified, SPECT-CT was more accurate anatomically. There was a significant change in surgical approach in 30 cases - breast cancer (n = 13; P 0.001) and malignant melanoma (n = 17; P 0.0002). In 4 cases a node not identified on planar imaging was seen on SPECT-CT. In 16 cases additional echelon nodes were identified. False positives were excluded by SPECT-CT in 12 cases. The addition of SPECT-CT and use of intra-operative gamma-probe to planar imaging offers important benefits in patients who present with breast cancer and melanoma. These benefits include increased nodal detection, elimination of false positives and negatives and improved anatomical localization that ultimately aids and expedites surgical management. This has been demonstrated in the context of industrialized country previously and has now also been confirmed in the setting of a emerging-market nation.

SPECT/CT imaging in general orthopedic practice.

PubMed

Scharf, Stephen

2009-09-01

The availability of hybrid devices that combine the latest single-photon emission computed tomography (SPECT) imaging technology with multislice computed tomography (CT) scanning has allowed us to detect subtle, nonspecific abnormalities on bone scans and interpret them as specific focal areas of pathology. Abnormalities in the spine can be separated into those caused by pars fractures, facet joint arthritis, or osteophyte formation on vertebral bodies. Compression fractures can be distinguished from severe degenerative disease, both of which can cause intense activity across the spine on either planar or SPECT imaging. Localizing activity in patients who have had spinal fusion can provide tremendous insight into the causes of therapeutic failures. Infections of the spine now can be diagnosed with gallium SPECT/CT, despite the fact that gallium has long been abandoned because of its failure to detect spine infection on either planar or SPECT imaging. Small focal abnormalities in the feet and ankles can be localized well enough to make specific orthopedic diagnoses on the basis of their location. Moreover, when radiographic imaging provides equivocal or inadequate information, SPECT/CT can provide a road map for further diagnostic studies and has been invaluable in planning surgery. Our ability to localize activity within a bone or at an articular surface has allowed us to distinguish between fractures and joint disease. Increased activity associated with congenital anomalies, such as tarsal coalition and Bertolotti's syndrome have allowed us to understand the pathophysiology of these conditions, to confirm them as the cause of the patient's symptoms, and to provide information that is useful in determining appropriate clinical management. As our experience broadens, SPECT/CT will undoubtedly become an important tool in the evaluation and management of a wider variety of orthopedic patients.

SPECT/CT with radiolabeled somatostatin analogues in the evaluation of systemic granulomatous infections

PubMed Central

Monteiro, Paulo Henrique Silva; de Souza, Thiago Ferreira; Moretti, Maria Luiza; Resende, Mariangela Ribeiro; Mengatti, Jair; de Lima, Mariana da Cunha Lopes; Santos, Allan Oliveira; Ramos, Celso Darío

2017-01-01

Objective To evaluate SPECT/CT with radiolabeled somatostatin analogues (RSAs) in systemic granulomatous infections in comparison with gallium-67 (67Ga) citrate scintigraphy. Materials and Methods We studied 28 patients with active systemic granulomatous infections, including tuberculosis, paracoccidioidomycosis, pneumocystosis, cryptococcosis, aspergillosis, leishmaniasis, infectious vasculitis, and an unspecified opportunistic infection. Of the 28 patients, 23 had started specific treatment before the study outset. All patients underwent whole-body SPECT/CT imaging: 7 after injection of 99mTc-EDDA-HYNIC-TOC, and 21 after injection of 111In-DTPA-octreotide. All patients also underwent 67Ga citrate imaging, except for one patient who died before the 67Ga was available. Results In 20 of the 27 patients who underwent imaging with both tracers, 27 sites of active disease were detected by 67Ga citrate imaging and by SPECT/CT with an RSA. Both tracers had negative results in the other 7 patients. RSA uptake was visually lower than 67Ga uptake in 11 of the 20 patients with positive images and similar to 67Ga uptake in the other 9 patients. The only patient who did not undergo 67Ga scintigraphy underwent 99mTc-EDDA-HYNIC-TOC SPECT/CT-guided biopsy of a lung cavity with focal RSA uptake, which turned to be positive for aspergillosis. Conclusion SPECT/CT with 99mTc-EDDA-HYNIC-TOC or 111In-DTPA-octreotide seems to be a good alternative to 67Ga citrate imaging for the evaluation of patients with systemic granulomatous disease. PMID:29307928

Technical Considerations on Scanning and Image Analysis for Amyloid PET in Dementia.

PubMed

Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Yamamoto, Yasuji; Senda, Michio

2017-01-01

Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice.

Optical Imaging of Ionizing Radiation from Clinical Sources

PubMed Central

Shaffer, Travis M.; Drain, Charles Michael

2016-01-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. PMID:27688469

Imaging of gene expression in live pancreatic islet cell lines using dual-isotope SPECT.

PubMed

Tai, Joo Ho; Nguyen, Binh; Wells, R Glenn; Kovacs, Michael S; McGirr, Rebecca; Prato, Frank S; Morgan, Timothy G; Dhanvantari, Savita

2008-01-01

We are combining nuclear medicine with molecular biology to establish a sensitive, quantitative, and tomographic method with which to detect gene expression in pancreatic islet cells in vivo. Dual-isotope SPECT can be used to image multiple molecular events simultaneously, and coregistration of SPECT and CT images enables visualization of reporter gene expression in the correct anatomic context. We have engineered pancreatic islet cell lines for imaging with SPECT/CT after transplantation under the kidney capsule. INS-1 832/13 and alphaTC1-6 cells were stably transfected with a herpes simplex virus type 1-thymidine kinase-green fluorescent protein (HSV1-thymidine kinase-GFP) fusion construct (tkgfp). After clonal selection, radiolabel uptake was determined by incubation with 5-(131)I-iodo-1-(2-deoxy-2-fluoro-beta-d-arabinofuranosyl)uracil ((131)I-FIAU) (alphaTC1-6 cells) or (123)I-FIAU (INS-1 832/13 cells). For the first set of in vivo experiments, SPECT was conducted after alphaTC1-6/tkgfp cells had been labeled with either (131)I-FIAU or (111)In-tropolone and transplanted under the left kidney capsule of CD1 mice. Reconstructed SPECT images were coregistered to CT. In a second study using simultaneous acquisition dual-isotope SPECT, INS-1 832/13 clone 9 cells were labeled with (111)In-tropolone before transplantation. Mice were then systemically administered (123)I-FIAU and data for both (131)I and (111)In were acquired simultaneously. alphaTC1-6/tkgfp cells showed a 15-fold greater uptake of (131)I-FIAU, and INS-1/tkgfp cells showed a 12-fold greater uptake of (123)I-FIAU, compared with that of wild-type cells. After transplantation under the kidney capsule, both reporter gene expression and location of cells could be visualized in vivo with dual-isotope SPECT. Immunohistochemistry confirmed the presence of glucagon- and insulin-positive cells at the site of transplantation. Dual-isotope SPECT is a promising method to detect gene expression in and location of transplanted pancreatic cells in vivo.

Exercise thallium-201 tomographic scintigraphy in the diagnosis of coronary artery disease: emphasis on the effect of exercise level.

PubMed

Huang, P J; Chieng, P U; Lee, Y T; Chiang, F T; Tseng, Y Z; Liau, C S; Tseng, C D; Su, C T; Lien, W P

1992-11-01

Exercise thallium-201 imaging using single-photon emission computed tomography (SPECT) was evaluated in 154 patients with angiographically documented coronary artery disease (CAD) and in 25 normal subjects. Of the 154 patients with CAD, 134 (87%) had abnormal thallium images. By contrast, only 77 (50%) patients had ischemic ST-segment depression (p < 0.001). Among 25 normal subjects, 20 had normal exercise SPECT images. The specificity of exercise SPECT imaging (80% or 20/25) in excluding patients with CAD was not significantly higher than that of exercise electrocardiography (76% or 19/25). For the detection of individual vessel involvement by analysis of territories of perfusion abnormalities, the sensitivity and specificity of exercise SPECT were 72% and 96% for the left anterior descending, 78% and 85% for the right coronary, and 47% and 98% for the left circumflex artery. Ninety (group 1) of the 154 patients with CAD achieved adequate exercise end points (ischemic ST-segment depression or > 85% of maximal predicted heart rate) and 64 (group 2) did not. Exercise SPECT showed significantly more perfusion abnormalities in group 1 than in group 2 (96% vs 75%, p < 0.001). We conclude that: (1) exercise SPECT thallium imaging is more sensitive than exercise electrocardiography for detecting patients with CAD; (2) the sensitivity of the test is affected by the level of exercise; and (3) it is valuable in the identification of individual vessel involvement.

Investigations of (99m)Tc-labeled glucarate as a SPECT radiotracer for non-small cell lung cancer (NSCLC) and potential tumor uptake mechanism.

PubMed

Meng, Lanfang; Xiu, Yan; Li, Yanli; Xu, Xiaobo; Li, Shanqun; Li, Xiao; Pak, Koon Y; Shi, Hongcheng; Cheng, Dengfeng

2015-07-01

This study attempted to evaluate the feasibility of (99m)Tc-labeled glucarate ((99m)Tc-GLA) imaging in non-small cell lung cancer (NSCLC) and the potential tumor uptake mechanism. Cell lysates from two NSCLC cell lines, H292 and H1975, were immunoblotted with anti-glucose transporter 5 (GLUT5) antibody for Western blotting. Thereafter, the two cell lines were used to examine cellular uptake of (99m)Tc-GLA with or without fructose. SPECT/CT imaging studies were performed on small animals bearing H292 and H1975 tumors. Biodistribution studies were also conducted to achieve accurate tissue uptake of this tracer in two tumor models. Hematoxylin & eosin (H&E) staining and GLUT5, Ki67 and cytokeratin-7 (CK-7) immunohistochemistry (IHC) analysis were further investigated on tumor tissues. In Western blotting, H292 cells showed higher levels of GLUT5 compared to the H1975 cells. Meanwhile, the in vitro cell assays indicated GLUT5-dependent uptake of (99m)Tc-GLA in H292 and H1975 cells. The fructose competition assays showed a significant decrease in (99m)Tc-GLA uptake by H292 and H1975 cells when fructose was added. The (99m)Tc-GLA accumulation was as much as two-fold higher in H292 implanted tumors than in H1975 implanted tumors. (99m)Tc-GLA exhibited rapid clearance pharmacokinetics and reasonable uptake in human NSCLC H292 (1.69±0.37 ID%/g) and H1975 (0.89±0.06 ID%/g) implanted tumors at 30min post injection. Finally, the expression of GLUT5, Ki67 and CK-7 on tumor tissues also exhibited positive correlation with the in vitro cell test results and in vivo SPECT/CT imaging results in xenograft tumors. Both in vitro and ex vivo studies demonstrated that the uptake of (99m)Tc-GLA in NSCLC is highly related to GLUT5 expression. Imaging and further IHC results support that (99m)Tc-GLA could be a promising SPECT imaging agent for NSCLC diagnosis and prognosis evaluation. Copyright © 2015 Elsevier Inc. All rights reserved.

Performance of 3DOSEM and MAP algorithms for reconstructing low count SPECT acquisitions.

PubMed

Grootjans, Willem; Meeuwis, Antoi P W; Slump, Cornelis H; de Geus-Oei, Lioe-Fee; Gotthardt, Martin; Visser, Eric P

2016-12-01

Low count single photon emission computed tomography (SPECT) is becoming more important in view of whole body SPECT and reduction of radiation dose. In this study, we investigated the performance of several 3D ordered subset expectation maximization (3DOSEM) and maximum a posteriori (MAP) algorithms for reconstructing low count SPECT images. Phantom experiments were conducted using the National Electrical Manufacturers Association (NEMA) NU2 image quality (IQ) phantom. The background compartment of the phantom was filled with varying concentrations of pertechnetate and indiumchloride, simulating various clinical imaging conditions. Images were acquired using a hybrid SPECT/CT scanner and reconstructed with 3DOSEM and MAP reconstruction algorithms implemented in Siemens Syngo MI.SPECT (Flash3D) and Hermes Hybrid Recon Oncology (Hyrid Recon 3DOSEM and MAP). Image analysis was performed by calculating the contrast recovery coefficient (CRC),percentage background variability (N%), and contrast-to-noise ratio (CNR), defined as the ratio between CRC and N%. Furthermore, image distortion is characterized by calculating the aspect ratio (AR) of ellipses fitted to the hot spheres. Additionally, the performance of these algorithms to reconstruct clinical images was investigated. Images reconstructed with 3DOSEM algorithms demonstrated superior image quality in terms of contrast and resolution recovery when compared to images reconstructed with filtered-back-projection (FBP), OSEM and 2DOSEM. However, occurrence of correlated noise patterns and image distortions significantly deteriorated the quality of 3DOSEM reconstructed images. The mean AR for the 37, 28, 22, and 17mm spheres was 1.3, 1.3, 1.6, and 1.7 respectively. The mean N% increase in high and low count Flash3D and Hybrid Recon 3DOSEM from 5.9% and 4.0% to 11.1% and 9.0%, respectively. Similarly, the mean CNR decreased in high and low count Flash3D and Hybrid Recon 3DOSEM from 8.7 and 8.8 to 3.6 and 4.2, respectively. Regularization with smoothing priors could suppress these noise patterns at the cost of reduced image contrast. The mean N% was 6.4% and 6.8% for low count QSP and MRP MAP reconstructed images. Alternatively, regularization with an anatomical Bowhser prior resulted in sharp images with high contrast, limited image distortion, and low N% of 8.3% in low count images, although some image artifacts did occur. Analysis of clinical images suggested that the same effects occur in clinical imaging. Image quality of low count SPECT acquisitions reconstructed with modern 3DOSEM algorithms is deteriorated by the occurrence of correlated noise patterns and image distortions. The artifacts observed in the phantom experiments can also occur in clinical imaging. Copyright © 2015. Published by Elsevier GmbH.

Refining diagnosis of Parkinson's disease with deep learning-based interpretation of dopamine transporter imaging.

PubMed

Choi, Hongyoon; Ha, Seunggyun; Im, Hyung Jun; Paek, Sun Ha; Lee, Dong Soo

2017-01-01

Dopaminergic degeneration is a pathologic hallmark of Parkinson's disease (PD), which can be assessed by dopamine transporter imaging such as FP-CIT SPECT. Until now, imaging has been routinely interpreted by human though it can show interobserver variability and result in inconsistent diagnosis. In this study, we developed a deep learning-based FP-CIT SPECT interpretation system to refine the imaging diagnosis of Parkinson's disease. This system trained by SPECT images of PD patients and normal controls shows high classification accuracy comparable with the experts' evaluation referring quantification results. Its high accuracy was validated in an independent cohort composed of patients with PD and nonparkinsonian tremor. In addition, we showed that some patients clinically diagnosed as PD who have scans without evidence of dopaminergic deficit (SWEDD), an atypical subgroup of PD, could be reclassified by our automated system. Our results suggested that the deep learning-based model could accurately interpret FP-CIT SPECT and overcome variability of human evaluation. It could help imaging diagnosis of patients with uncertain Parkinsonism and provide objective patient group classification, particularly for SWEDD, in further clinical studies.

SPECT System Optimization Against A Discrete Parameter Space

PubMed Central

Meng, L. J.; Li, N.

2013-01-01

In this paper, we present an analytical approach for optimizing the design of a static SPECT system or optimizing the sampling strategy with a variable/adaptive SPECT imaging hardware against an arbitrarily given set of system parameters. This approach has three key aspects. First, it is designed to operate over a discretized system parameter space. Second, we have introduced an artificial concept of virtual detector as the basic building block of an imaging system. With a SPECT system described as a collection of the virtual detectors, one can convert the task of system optimization into a process of finding the optimum imaging time distribution (ITD) across all virtual detectors. Thirdly, the optimization problem (finding the optimum ITD) could be solved with a block-iterative approach or other non-linear optimization algorithms. In essence, the resultant optimum ITD could provide a quantitative measure of the relative importance (or effectiveness) of the virtual detectors and help to identify the system configuration or sampling strategy that leads to an optimum imaging performance. Although we are using SPECT imaging as a platform to demonstrate the system optimization strategy, this development also provides a useful framework for system optimization problems in other modalities, such as positron emission tomography (PET) and X-ray computed tomography (CT) [1, 2]. PMID:23587609

Infective endocarditis detection through SPECT/CT images digital processing

NASA Astrophysics Data System (ADS)

Moreno, Albino; Valdés, Raquel; Jiménez, Luis; Vallejo, Enrique; Hernández, Salvador; Soto, Gabriel

2014-03-01

Infective endocarditis (IE) is a difficult-to-diagnose pathology, since its manifestation in patients is highly variable. In this work, it was proposed a semiautomatic algorithm based on SPECT images digital processing for the detection of IE using a CT images volume as a spatial reference. The heart/lung rate was calculated using the SPECT images information. There were no statistically significant differences between the heart/lung rates values of a group of patients diagnosed with IE (2.62+/-0.47) and a group of healthy or control subjects (2.84+/-0.68). However, it is necessary to increase the study sample of both the individuals diagnosed with IE and the control group subjects, as well as to improve the images quality.

Pre-operative prediction of cervical nodal metastasis in papillary thyroid cancer by 99mTc-MIBI SPECT/CT; a pilot study.

PubMed

Tangjaturonrasme, Napadon; Vasavid, Pataramon; Sombuntham, Premsuda; Keelawat, Somboon

2013-06-01

Papillary thyroid cancer has a high prevalence of cervical nodal metastasis. There is no "gold standard" imaging for pre-operative diagnosis. The aim of the present study was to assess the accuracy of pre-operative 99mTc-MBI SPECT/CT in diagnosis of cervical nodal metastasis in patients with papillary thyroid cancer Fifteen patients were performed 99Tc-MlBI SPECT/CT pre-operatively. Either positive pathological report of neck dissection or positive post-treatment I-131 whole body scan with SPECT/CT of neck was concluded for definite neck metastasis. The PPV, NPV, and accuracy of 99mTc-MIBI SPECT/CT were analyzed. The PPV NPV and accuracy were 80%, 88.89%, and 85.71%, respectively. 99mTc-MIBI SPECT/CT could localize the abnormal lymph nodes groups correctly in most cases when compared with pathological results. However the authors found one false positive case with caseating granulomatous lymphadenitis and one false negative case with positive post-treatment 1-131 whole body scan with SPECT/CT of neck on cervical nodes zone II and IV CONCLUSION: 99mTc-MIBI SPECT/CTseem promising for pre-operative staging of cervical nodal involvement in patients with papillary thyroid cancer without the need of using iodinated contrast that may complicate subsequence 1-131 treatment. However, false positive result in granulomatous inflammatory nodes should be aware of especially in endemic areas. 99mTc-MIBI SPECT/CT scan shows a good result when compared with previous study of CT or MRI imaging. The comparative study between different imaging modality and the extension of neck dissection according to MIBI result seems interesting.

Development and validation of technique for in-vivo 3D analysis of cranial bone graft survival

NASA Astrophysics Data System (ADS)

Bernstein, Mark P.; Caldwell, Curtis B.; Antonyshyn, Oleh M.; Ma, Karen; Cooper, Perry W.; Ehrlich, Lisa E.

1997-05-01

Bone autografts are routinely employed in the reconstruction of facial deformities resulting from trauma, tumor ablation or congenital malformations. The combined use of post- operative 3D CT and SPECT imaging provides a means for quantitative in vivo evaluation of bone graft volume and osteoblastic activity. The specific objectives of this study were: (1) Determine the reliability and accuracy of interactive computer-assisted analysis of bone graft volumes based on 3D CT scans; (2) Determine the error in CT/SPECT multimodality image registration; (3) Determine the error in SPECT/SPECT image registration; and (4) Determine the reliability and accuracy of CT-guided SPECT uptake measurements in cranial bone grafts. Five human cadaver heads served as anthropomorphic models for all experiments. Four cranial defects were created in each specimen with inlay and onlay split skull bone grafts and reconstructed to skull and malar recipient sites. To acquire all images, each specimen was CT scanned and coated with Technetium doped paint. For purposes of validation, skulls were landmarked with 1/16-inch ball-bearings and Indium. This study provides a new technique relating anatomy and physiology for the analysis of cranial bone graft survival.

Hybrid-fusion SPECT/CT systems in parathyroid adenoma: Technological improvements and added clinical diagnostic value.

PubMed

Wong, K K; Chondrogiannis, S; Bowles, H; Fuster, D; Sánchez, N; Rampin, L; Rubello, D

Nuclear medicine traditionally employs planar and single photon emission computed tomography (SPECT) imaging techniques to depict the biodistribution of radiotracers for the diagnostic investigation of a range of disorders of endocrine gland function. The usefulness of combining functional information with anatomy derived from computed tomography (CT), magnetic resonance imaging (MRI), and high resolution ultrasound (US), has long been appreciated, either using visual side-by-side correlation, or software-based co-registration. The emergence of hybrid SPECT/CT camera technology now allows the simultaneous acquisition of combined multi-modality imaging, with seamless fusion of 3D volume datasets. Thus, it is not surprising that there is growing literature describing the many advantages that contemporary SPECT/CT technology brings to radionuclide investigation of endocrine disorders, showing potential advantages for the pre-operative locating of the parathyroid adenoma using a minimally invasive surgical approach, especially in the presence of ectopic glands and in multiglandular disease. In conclusion, hybrid SPECT/CT imaging has become an essential tool to ensure the most accurate diagnostic in the management of patients with hyperparathyroidism. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Fully automatic multi-atlas segmentation of CTA for partial volume correction in cardiac SPECT/CT

NASA Astrophysics Data System (ADS)

Liu, Qingyi; Mohy-ud-Din, Hassan; Boutagy, Nabil E.; Jiang, Mingyan; Ren, Silin; Stendahl, John C.; Sinusas, Albert J.; Liu, Chi

2017-05-01

Anatomical-based partial volume correction (PVC) has been shown to improve image quality and quantitative accuracy in cardiac SPECT/CT. However, this method requires manual segmentation of various organs from contrast-enhanced computed tomography angiography (CTA) data. In order to achieve fully automatic CTA segmentation for clinical translation, we investigated the most common multi-atlas segmentation methods. We also modified the multi-atlas segmentation method by introducing a novel label fusion algorithm for multiple organ segmentation to eliminate overlap and gap voxels. To evaluate our proposed automatic segmentation, eight canine 99mTc-labeled red blood cell SPECT/CT datasets that incorporated PVC were analyzed, using the leave-one-out approach. The Dice similarity coefficient of each organ was computed. Compared to the conventional label fusion method, our proposed label fusion method effectively eliminated gaps and overlaps and improved the CTA segmentation accuracy. The anatomical-based PVC of cardiac SPECT images with automatic multi-atlas segmentation provided consistent image quality and quantitative estimation of intramyocardial blood volume, as compared to those derived using manual segmentation. In conclusion, our proposed automatic multi-atlas segmentation method of CTAs is feasible, practical, and facilitates anatomical-based PVC of cardiac SPECT/CT images.

Chlorotoxin-Conjugated Multifunctional Dendrimers Labeled with Radionuclide 131I for Single Photon Emission Computed Tomography Imaging and Radiotherapy of Gliomas.

PubMed

Zhao, Lingzhou; Zhu, Jingyi; Cheng, Yongjun; Xiong, Zhijuan; Tang, Yueqin; Guo, Lilei; Shi, Xiangyang; Zhao, Jinhua

2015-09-09

Chlorotoxin-conjugated multifunctional dendrimers labeled with radionuclide 131I were synthesized and utilized for targeted single photon emission computed tomography (SPECT) imaging and radiotherapy of cancer. In this study, generation five amine-terminated poly(amidoamine) dendrimers were used as a platform to be sequentially conjugated with polyethylene glycol (PEG), targeting agent chlorotoxin (CTX), and 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO). This was followed by acetylation of the remaining dendrimer terminal amines and radiolabeling with 131I to form the targeted theranostic dendrimeric nanoplatform. We show that the dendrimer platform possessing approximately 7.7 CTX and 21.1 HPAO moieties on each dendrimer displays excellent cytocompatibility in a given concentration range (0-20 μM) and can specifically target cancer cells overexpressing matrix metallopeptidase 2 (MMP2) due to the attached CTX. With the attached HPAO moiety having the phenol group, the dendrimer platform can be effectively labeled with radioactive 131I with good stability and high radiochemical purity. Importantly, the 131I labeling renders the dendrimer platform with an ability to be used for targeted SPECT imaging and radiotherapy of an MMP2-overexpressing glioma model in vivo. The developed radiolabeled multifunctional dendrimeric nanoplatform may hold great promise to be used for targeted theranostics of human gliomas.

Optical Imaging of Ionizing Radiation from Clinical Sources.

PubMed

Shaffer, Travis M; Drain, Charles Michael; Grimm, Jan

2016-11-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Correlation-based perfusion mapping using time-resolved MR angiography: A feasibility study for patients with suspicions of steno-occlusive craniocervical arteries.

PubMed

Nam, Yoonho; Jang, Jinhee; Park, Sonya Youngju; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin; Kim, Bum-Soo

2018-05-22

To explore the feasibility of using correlation-based time-delay (CTD) maps produced from time-resolved MR angiography (TRMRA) to diagnose perfusion abnormalities in patients suspected to have steno-occlusive lesions in the craniocervical arteries. Twenty-seven patients who were suspected to have steno-occlusive lesions in the craniocervical arteries underwent both TRMRA and brain single-photon emission computed tomography (SPECT). TRMRA was performed on the supra-aortic area after intravenous injection of a 0.03 mmol/kg gadolinium-based contrast agent. Time-to-peak (TTP) maps and CTD maps of the brain were automatically generated from TRMRA data, and their quality was assessed. Detection of perfusion abnormalities was compared between CTD maps and the time-series maximal intensity projection (MIP) images from TRMRA and TTP maps. Correlation coefficients between quantitative changes in SPECT and parametric maps for the abnormal perfusion areas were calculated. The CTD maps were of significantly superior quality than TTP maps (p < 0.01). For perfusion abnormality detection, CTD maps (kappa 0.84, 95% confidence interval [CI] 0.67-1.00) showed better agreement with SPECT than TTP maps (0.66, 0.46-0.85). For perfusion deficit detection, CTD maps showed higher accuracy (85.2%, 95% CI 66.3-95.8) than MIP images (66.7%, 46-83.5), with marginal significance (p = 0.07). In abnormal perfusion areas, correlation coefficients between SPECT and CTD (r = 0.74, 95% CI 0.34-0.91) were higher than those between SPECT and TTP (r = 0.66, 0.20-0.88). CTD maps generated from TRMRA were of high quality and offered good diagnostic performance for detecting perfusion abnormalities associated with steno-occlusive arterial lesions in the craniocervical area. • Generation of perfusion parametric maps from time-resolved MR angiography is clinically useful. • Correlation-based delay maps can be used to detect perfusion abnormalities associated with steno-occlusive craniocervical arteries. • Estimation of correlation-based delay is robust for low signal-to-noise 4D MR data.

Spatially resolved assessment of hepatic function using 99mTc-IDA SPECT

PubMed Central

Wang, Hesheng; Cao, Yue

2013-01-01

Purpose: 99mTc-iminodiacetic acid (IDA) hepatobiliary imaging is usually quantified for hepatic function on the entire liver or regions of interest (ROIs) in the liver. The authors presented a method to estimate the hepatic extraction fraction (HEF) voxel-by-voxel from single-photon emission computed tomography (SPECT)/CT with a 99mTc-labeled IDA agent of mebrofenin and evaluated the spatially resolved HEF measurements with an independent physiological measurement. Methods: Fourteen patients with intrahepatic cancers were treated with radiation therapy (RT) and imaged by 99mTc-mebrofenin SPECT before and 1 month after RT. The dynamic SPECT volumes were with a resolution of 3.9 × 3.9 × 2.5 mm3. Throughout the whole liver with approximate 50 000 voxels, voxelwise HEF quantifications were estimated and compared between using arterial input function (AIF) from the heart and using vascular input function (VIF) from the spleen. The correlation between mean of the HEFs over the nontumor liver tissue and the overall liver function measured by Indocyanine green clearance half-time (T1/2) was assessed. Variation of the voxelwise estimation was evaluated in ROIs drawn in relatively homogeneous regions of the livers. The authors also examined effects of the time range parameter on the voxelwise HEF quantification. Results: Mean of the HEFs over the liver estimated using AIF significantly correlated with the physiological measurement T1/2 (r = 0.52, p = 0.0004), and the correlation was greatly improved by using VIF (r = 0.79, p < 0.0001). The parameter of time range for the retention phase did not lead to a significant difference in the means of the HEFs in the ROIs. Using VIF and a retention phase time range of 7–30 min, the relative variation of the voxelwise HEF in the ROIs was 10% ± 6% of respective mean HEF. Conclusions: The voxelwise HEF derived from 99mTc-IDA SPECT by the deconvolution analysis is feasible to assess the spatial distribution of hepatic function in the liver. PMID:24007177

Collimator design for a multipinhole brain SPECT insert for MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Audenhaege, Karen; Van Holen, Roel; Vanhove, Christian

Purpose: Brain single photon emission computed tomography (SPECT) imaging is an important clinical tool, with unique tracers for studying neurological diseases. Nowadays, most commercial SPECT systems are combined with x-ray computed tomography (CT) in so-called SPECT/CT systems to obtain an anatomical background for the functional information. However, while CT images have a high spatial resolution, they have a low soft-tissue contrast, which is an important disadvantage for brain imaging. Magnetic resonance imaging (MRI), on the other hand, has a very high soft-tissue contrast and does not involve extra ionizing radiation. Therefore, the authors designed a brain SPECT insert that canmore » operate inside a clinical MRI. Methods: The authors designed and simulated a compact stationary multipinhole SPECT insert based on digital silicon photomultiplier detector modules, which have shown to be MR-compatible and have an excellent intrinsic resolution (0.5 mm) when combined with a monolithic 2 mm thick LYSO crystal. First, the authors optimized the different parameters of the SPECT system to maximize sensitivity for a given target resolution of 7.2 mm in the center of the field-of-view, given the spatial constraints of the MR system. Second, the authors performed noiseless simulations of two multipinhole configurations to evaluate sampling and reconstructed resolution. Finally, the authors performed Monte Carlo simulations and compared the SPECT insert with a clinical system with ultrahigh-resolution (UHR) fan beam collimators, based on contrast-to-noise ratio and a visual comparison of a Hoffman phantom with a 9 mm cold lesion. Results: The optimization resulted in a stationary multipinhole system with a collimator radius of 150.2 mm and a detector radius of 172.67 mm, which corresponds to four rings of 34 diSPM detector modules. This allows the authors to include eight rings of 24 pinholes, which results in a system volume sensitivity of 395 cps/MBq. Noiseless simulations show sufficient axial sampling (in a Defrise phantom) and a reconstructed resolution of 5.0 mm (in a cold-rod phantom). The authors compared the 24-pinhole setup with a 34-pinhole system (with the same detector radius but a collimator radius of 156.63 mm) and found that 34 pinholes result in better uniformity but a worse reconstruction of the cold-rod phantom. The authors also compared the 24-pinhole system with a clinical triple-head UHR fan beam system based on contrast-to-noise ratio and found that the 24-pinhole setup performs better for the 6 mm hot and the 16 mm cold lesions and worse for the 8 and 10 mm hot lesions. Finally, the authors reconstructed noisy projection data of a Hoffman phantom with a 9 mm cold lesion and found that the lesion was slightly better visible on the multipinhole image compared to the fan beam image. Conclusions: The authors have optimized a stationary multipinhole SPECT insert for MRI and showed the feasibility of doing brain SPECT imaging inside a MRI with an image quality similar to the best clinical SPECT systems available.« less

Imaging discordance between hepatic angiography versus Tc-99m-MAA SPECT/CT: a case series, technical discussion and clinical implications.

PubMed

Kao, Yung Hsiang; Tan, Eik Hock; Teo, Terence Kiat Beng; Ng, Chee Eng; Goh, Soon Whatt

2011-11-01

During pre-therapy evaluation for yttrium-90 (Y-90) radioembolization, it is uncommon to find severe imaging discordance between hepatic angiography versus technetium-99m-macroaggregated albumin (Tc-99m-MAA) single photon emission computed tomography with integrated low-dose CT (SPECT/CT). The reasons for severe imaging discordance are unclear, and literature is scarce. We describe 3 patients with severe imaging discordance, whereby tumor angiographic contrast hypervascularity was markedly mismatched to the corresponding Tc-99m-MAA SPECT/CT, and its clinical impact. The incidence of severe imaging discordance at our institution was 4% (3 of 74 cases). We postulate that imaging discordance could be due to a combination of 3 factors: (1) different injection rates between soluble contrast molecules versus Tc-99m-MAA; (2) different arterial flow hemodynamics between soluble contrast molecules versus Tc-99m-MAA; (3) eccentric release position of Tc-99m-MAA due to microcatheter tip location, inadvertently selecting non-target microparticle trajectories. Tc-99m-MAA SPECT/CT more accurately represents hepatic microparticle biodistribution than soluble contrast hepatic angiography and should be a key criterion in patient selection for Y-90 radioembolization. Tc-99m-MAA SPECT/CT provides more information than planar scintigraphy to guide radiation planning and clinical decision making. Severe imaging discordance at pre-therapy evaluation is ominous and should be followed up by changes to the final vascular approach during Y-90 radioembolization.

Optimizing and Evaluating an Integrated SPECT-CmT System Dedicated to Improved 3-D Breast Cancer Imaging

DTIC Science & Technology

2009-05-01

sagittal slices of a breast cancer patient (42yrs, 68kg) with implant and biopsy clip and various identified tissues . Glandular Adipose Implant...Biopsy Clip 13 volumetric imaging to effectively differentiate between normal glandular, adipose tissue and the artificial implants. It is...impacting the lowered head section. A. SPECT Sub-System The main component of the SPECT sub-system is a compact 16x20cm2 field of view Cadmium - Zinc

Phospholipid ether analogs for the detection of colorectal tumors.

PubMed

Deming, Dustin A; Maher, Molly E; Leystra, Alyssa A; Grudzinski, Joseph P; Clipson, Linda; Albrecht, Dawn M; Washington, Mary Kay; Matkowskyj, Kristina A; Hall, Lance T; Lubner, Sam J; Weichert, Jamey P; Halberg, Richard B

2014-01-01

The treatment of localized colorectal cancer (CRC) depends on resection of the primary tumor with adequate margins and sufficient lymph node sampling. A novel imaging agent that accumulates in CRCs and the associated lymph nodes is needed. Cellectar Biosciences has developed a phospholipid ether analog platform that is both diagnostic and therapeutic. CLR1502 is a near-infrared fluorescent molecule, whereas 124/131I-CLR1404 is under clinical investigation as a PET tracer/therapeutic agent imaged by SPECT. We investigated the use of CLR1502 for the detection of intestinal cancers in a murine model and 131I-CLR1404 in a patient with metastatic CRC. Mice that develop multiple intestinal tumors ranging from adenomas to locally advanced adenocarcinomas were utilized. After 96 hours post CLR1502 injection, the intestinal tumors were analyzed using a Spectrum IVIS (Perkin Elmer) and a Fluobeam (Fluoptics). The intensity of the fluorescent signal was correlated with the histological characteristics for each tumor. Colon adenocarcinomas demonstrated increased accumulation of CLR1502 compared to non-invasive lesions (total radiant efficiency: 1.76×10(10) vs 3.27×10(9) respectively, p = 0.006). Metastatic mesenteric tumors and uninvolved lymph nodes were detected with CLR1502. In addition, SPECT imaging with 131I-CLR1404 was performed as part of a clinical trial in patients with advanced solid tumors. 131I-CLR1404 was shown to accumulate in metastatic tumors in a patient with colorectal adenocarcinoma. Together, these compounds might enhance our ability to properly resect CRCs through better localization of the primary tumor and improved lymph node identification as well as detect distant disease.

Phospholipid Ether Analogs for the Detection of Colorectal Tumors

PubMed Central

Deming, Dustin A.; Maher, Molly E.; Leystra, Alyssa A.; Grudzinski, Joseph P.; Clipson, Linda; Albrecht, Dawn M.; Washington, Mary Kay; Matkowskyj, Kristina A.; Hall, Lance T.; Lubner, Sam J.; Weichert, Jamey P.; Halberg, Richard B.

2014-01-01

The treatment of localized colorectal cancer (CRC) depends on resection of the primary tumor with adequate margins and sufficient lymph node sampling. A novel imaging agent that accumulates in CRCs and the associated lymph nodes is needed. Cellectar Biosciences has developed a phospholipid ether analog platform that is both diagnostic and therapeutic. CLR1502 is a near-infrared fluorescent molecule, whereas 124/131I-CLR1404 is under clinical investigation as a PET tracer/therapeutic agent imaged by SPECT. We investigated the use of CLR1502 for the detection of intestinal cancers in a murine model and 131I-CLR1404 in a patient with metastatic CRC. Mice that develop multiple intestinal tumors ranging from adenomas to locally advanced adenocarcinomas were utilized. After 96 hours post CLR1502 injection, the intestinal tumors were analyzed using a Spectrum IVIS (Perkin Elmer) and a Fluobeam (Fluoptics). The intensity of the fluorescent signal was correlated with the histological characteristics for each tumor. Colon adenocarcinomas demonstrated increased accumulation of CLR1502 compared to non-invasive lesions (total radiant efficiency: 1.76×1010 vs 3.27×109 respectively, p = 0.006). Metastatic mesenteric tumors and uninvolved lymph nodes were detected with CLR1502. In addition, SPECT imaging with 131I-CLR1404 was performed as part of a clinical trial in patients with advanced solid tumors. 131I-CLR1404 was shown to accumulate in metastatic tumors in a patient with colorectal adenocarcinoma. Together, these compounds might enhance our ability to properly resect CRCs through better localization of the primary tumor and improved lymph node identification as well as detect distant disease. PMID:25286226

A novel three-dimensional image reconstruction method for near-field coded aperture single photon emission computerized tomography

PubMed Central

Mu, Zhiping; Hong, Baoming; Li, Shimin; Liu, Yi-Hwa

2009-01-01

Coded aperture imaging for two-dimensional (2D) planar objects has been investigated extensively in the past, whereas little success has been achieved in imaging 3D objects using this technique. In this article, the authors present a novel method of 3D single photon emission computerized tomography (SPECT) reconstruction for near-field coded aperture imaging. Multiangular coded aperture projections are acquired and a stack of 2D images is reconstructed separately from each of the projections. Secondary projections are subsequently generated from the reconstructed image stacks based on the geometry of parallel-hole collimation and the variable magnification of near-field coded aperture imaging. Sinograms of cross-sectional slices of 3D objects are assembled from the secondary projections, and the ordered subset expectation and maximization algorithm is employed to reconstruct the cross-sectional image slices from the sinograms. Experiments were conducted using a customized capillary tube phantom and a micro hot rod phantom. Imaged at approximately 50 cm from the detector, hot rods in the phantom with diameters as small as 2.4 mm could be discerned in the reconstructed SPECT images. These results have demonstrated the feasibility of the authors’ 3D coded aperture image reconstruction algorithm for SPECT, representing an important step in their effort to develop a high sensitivity and high resolution SPECT imaging system. PMID:19544769

A COMPUTER MODEL OF LUNG MORPHOLOGY TO ANALYZE SPECT IMAGES

EPA Science Inventory

Measurement of the three-dimensional (3-D) spatial distribution of aerosol deposition can be performed using Single Photon Emission Computed Tomography (SPECT). The advantage of using 3-D techniques over planar gamma imaging is that deposition patterns can be related to real lun...

Head-to-Head Visual Comparison between Brain Perfusion SPECT and Arterial Spin-Labeling MRI with Different Postlabeling Delays in Alzheimer Disease.

PubMed

Kaneta, T; Katsuse, O; Hirano, T; Ogawa, M; Yoshida, K; Odawara, T; Hirayasu, Y; Inoue, T

2017-08-01

Arterial spin-labeling MR imaging has been recently developed as a noninvasive technique with magnetically labeled arterial blood water as an endogenous contrast medium for the evaluation of CBF. Our aim was to compare arterial spin-labeling MR imaging and SPECT in the visual assessment of CBF in patients with Alzheimer disease. In 33 patients with Alzheimer disease or mild cognitive impairment due to Alzheimer disease, CBF images were obtained by using both arterial spin-labeling-MR imaging with a postlabeling delay of 1.5 seconds and 2.5 seconds (PLD 1.5 and PLD 2.5 , respectively) and brain perfusion SPECT. Twenty-two brain regions were visually assessed, and the diagnostic confidence of Alzheimer disease was recorded. Among all arterial spin-labeling images, 84.9% of PLD 1.5 and 9% of PLD 2.5 images showed the typical pattern of advanced Alzheimer disease (ie, decreased CBF in the bilateral parietal, temporal, and frontal lobes). PLD 1.5 , PLD 2.5 , and SPECT imaging resulted in obviously different visual assessments. PLD 1.5 showed a broad decrease in CBF, which could have been due to an early perfusion. In contrast, PLD 2.5 did not appear to be influenced by an early perfusion but showed fewer pathologic findings than SPECT. The distinctions observed by us should be carefully considered in the visual assessments of Alzheimer disease. Further studies are required to define the patterns of change in arterial spin-labeling-MR imaging associated with Alzheimer disease. © 2017 by American Journal of Neuroradiology.

Validation of a Multimodality Flow Phantom and Its Application for Assessment of Dynamic SPECT and PET Technologies.

PubMed

Gabrani-Juma, Hanif; Clarkin, Owen J; Pourmoghaddas, Amir; Driscoll, Brandon; Wells, R Glenn; deKemp, Robert A; Klein, Ran

2017-01-01

Simple and robust techniques are lacking to assess performance of flow quantification using dynamic imaging. We therefore developed a method to qualify flow quantification technologies using a physical compartment exchange phantom and image analysis tool. We validate and demonstrate utility of this method using dynamic PET and SPECT. Dynamic image sequences were acquired on two PET/CT and a cardiac dedicated SPECT (with and without attenuation and scatter corrections) systems. A two-compartment exchange model was fit to image derived time-activity curves to quantify flow rates. Flowmeter measured flow rates (20-300 mL/min) were set prior to imaging and were used as reference truth to which image derived flow rates were compared. Both PET cameras had excellent agreement with truth ( [Formula: see text]). High-end PET had no significant bias (p > 0.05) while lower-end PET had minimal slope bias (wash-in and wash-out slopes were 1.02 and 1.01) but no significant reduction in precision relative to high-end PET (<15% vs. <14% limits of agreement, p > 0.3). SPECT (without scatter and attenuation corrections) slope biases were noted (0.85 and 1.32) and attributed to camera saturation in early time frames. Analysis of wash-out rates from non-saturated, late time frames resulted in excellent agreement with truth ( [Formula: see text], slope = 0.97). Attenuation and scatter corrections did not significantly impact SPECT performance. The proposed phantom, software and quality assurance paradigm can be used to qualify imaging instrumentation and protocols for quantification of kinetic rate parameters using dynamic imaging.

CT-based attenuation correction and resolution compensation for I-123 IMP brain SPECT normal database: a multicenter phantom study.

PubMed

Inui, Yoshitaka; Ichihara, Takashi; Uno, Masaki; Ishiguro, Masanobu; Ito, Kengo; Kato, Katsuhiko; Sakuma, Hajime; Okazawa, Hidehiko; Toyama, Hiroshi

2018-06-01

Statistical image analysis of brain SPECT images has improved diagnostic accuracy for brain disorders. However, the results of statistical analysis vary depending on the institution even when they use a common normal database (NDB), due to different intrinsic spatial resolutions or correction methods. The present study aimed to evaluate the correction of spatial resolution differences between equipment and examine the differences in skull bone attenuation to construct a common NDB for use in multicenter settings. The proposed acquisition and processing protocols were those routinely used at each participating center with additional triple energy window (TEW) scatter correction (SC) and computed tomography (CT) based attenuation correction (CTAC). A multicenter phantom study was conducted on six imaging systems in five centers, with either single photon emission computed tomography (SPECT) or SPECT/CT, and two brain phantoms. The gray/white matter I-123 activity ratio in the brain phantoms was 4, and they were enclosed in either an artificial adult male skull, 1300 Hounsfield units (HU), a female skull, 850 HU, or an acrylic cover. The cut-off frequency of the Butterworth filters was adjusted so that the spatial resolution was unified to a 17.9 mm full width at half maximum (FWHM), that of the lowest resolution system. The gray-to-white matter count ratios were measured from SPECT images and compared with the actual activity ratio. In addition, mean, standard deviation and coefficient of variation images were calculated after normalization and anatomical standardization to evaluate the variability of the NDB. The gray-to-white matter count ratio error without SC and attenuation correction (AC) was significantly larger for higher bone densities (p < 0.05). The count ratio error with TEW and CTAC was approximately 5% regardless of bone density. After adjustment of the spatial resolution in the SPECT images, the variability of the NDB decreased and was comparable to that of the NDB without correction. The proposed protocol showed potential for constructing an appropriate common NDB from SPECT images with SC, AC and spatial resolution compensation.

Myocardial viability assessment with dynamic low-dose iodine-123-iodophenylpentadecanoic acid metabolic imaging: comparison with myocardial biopsy and reinjection SPECT thallium after myocardial infarction.

PubMed

Murray, G L; Schad, N C; Magill, H L; Vander Zwaag, R

1994-04-01

Aggressive cardiac revascularization requires recognition of stunned and hibernating myocardium, and cost considerations may well govern the technique used. Dynamic low-dose (1 mCi) [123I]iodophenylpentadecanoic acid (IPPA) metabolic imaging is a potential alternative to PET using either 18FDG or 15O-water. Resting IPPA images were obtained from patients with severe ischemic cardiomyopathy, and transmural myocardial biopsies were obtained during coronary bypass surgery to confirm viability. Thirty-nine of 43 (91%) biopsies confirmed the results of the IPPA images with a sensitivity for viability of 33/36 (92%) and a specificity of 6/7 (86%). Postoperatively, wall motion improved in 80% of IPPA-viable, dysfunctional segments. Furthermore, when compared to reinjection thallium (SPECT-TI) scans after myocardial infarction, IPPA-SPECT-TI concordance occurred in 27/35 (77%) (K = 0.536, p = 0.0003). Similar to PET, IPPA demonstrated more viability than SPECT-TI, 26/35 (74%) versus 18/35 (51%) (p = 0.047). Metabolic IPPA cardiac viability imaging is a safe, inexpensive technique that may be a useful alternative to PET.

Influence of proton-pump inhibitors on stomach wall uptake of 99mTc-tetrofosmin in cadmium-zinc-telluride SPECT myocardial perfusion imaging.

PubMed

Mouden, Mohamed; Rijkee, Karlijn S; Schreuder, Nanno; Timmer, Jorik R; Jager, Pieter L

2015-02-01

Proton-pump inhibitors (PPIs) induce potentially interfering stomach wall activity in single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) with technetium-99m ((99m)Tc)-sestamibi. However, no data are available for (99m)Tc-tetrofosmin. We assessed the influence of prolonged (>2 weeks) PPI use on the stomach wall uptake of (99m)Tc-tetrofosmin in patients referred for stress MPI with a cadmium-zinc-telluride-based SPECT camera and its relation with dyspepsia symptoms. Consecutive patients (n=127) underwent a 1-day adenosine stress-first SPECT-MPI with (99m)Tc-tetrofosmin, of whom 54 (43%) patients had been on PPIs for more than 2 weeks. Stomach wall activity was identified on stress SPECT using computed tomographic attenuation maps and was scored using a four-point grading scale into clinically relevant (scores 2 or 3) or nonrelevant (scores 0 or 1).Patients on PPIs had stomach wall uptake more frequently as compared with patients not using PPIs (22 vs. 7%, P=0.017). Dyspepsia was similar in both groups. Prolonged use of PPIs is associated with stomach wall uptake of (99m)Tc-tetrofosmin in stress cadmium-zinc-telluride-SPECT images. Gastric symptoms were not associated with stomach wall uptake.

Experimental MRI-SPECT insert system with Hybrid Semiconductor detectors Timepix for MR animal scanner Bruker 47/20

NASA Astrophysics Data System (ADS)

Zajicek, J.; Burian, M.; Soukup, P.; Novak, V.; Macko, M.; Jakubek, J.

2017-01-01

Multimodal medical imaging based on Magnetic Resonance is mainly combinated with one of the scintigraphic method like PET or SPECT. These methods provide functional information whereas magnetic resonance imaging provides high spatial resolution of anatomical information or complementary functional information. Fusion of imaging modalities allows researchers to obtain complimentary information in a single measurement. The combination of MRI with SPECT is still relatively new and challenging in many ways. The main complication of using SPECT in MRI systems is the presence of a high magnetic field therefore (ferro)magnetic materials have to be eliminated. Furthermore the application of radiofrequency fields within the MR gantry does not allow for the use of conductive structures such as the common heavy metal collimators. This work presents design and construction of an experimental MRI-SPECT insert system and its initial tests. This unique insert system consists of an MR-compatible SPECT setup with CdTe pixelated sensors Timepix tungsten collimators and a radiofrequency coil. Measurements were performed on a gelatine and tissue phantom with an embedded radioisotopic source (57Co 122 keV γ ray) inside the RF coil by the Bruker BioSpec 47/20 (4.7 T) MR animal scanner. The project was performed in the framework of the Medipix Collaboration.

Potential advantage of studying the lymphatic drainage by sentinel node technique and SPECT-CT image fusion for pelvic irradiation of prostate cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krengli, Marco; Ballare, Andrea; Cannillo, Barbara

2006-11-15

Purpose: This study aims to investigate the in vivo drainage of lymphatic spread by using the sentinel node (SN) technique and single-photon emission computed tomography (SPECT)-computed tomography (CT) image fusion, and to analyze the impact of such information on conformal pelvic irradiation. Methods and Materials: Twenty-three prostate cancer patients, candidates for radical prostatectomy already included in a trial studying the SN technique, were enrolled. CT and SPECT images were obtained after intraprostate injection of 115 MBq of {sup 99m}Tc-nanocolloid, allowing identification of SN and other pelvic lymph nodes. Target and nontarget structures, including lymph nodes identified by SPECT, were drawnmore » on SPECT-CT fusion images. A three-dimensional conformal treatment plan was performed for each patient. Results: Single-photon emission computed tomography lymph nodal uptake was detected in 20 of 23 cases (87%). The SN was inside the pelvic clinical target volume (CTV{sub 2}) in 16 of 20 cases (80%) and received no less than the prescribed dose in 17 of 20 cases (85%). The most frequent locations of SN outside the CTV{sub 2} were the common iliac and presacral lymph nodes. Sixteen of the 32 other lymph nodes (50%) identified by SPECT were found outside the CTV{sub 2}. Overall, the SN and other intrapelvic lymph nodes identified by SPECT were not included in the CTV{sub 2} in 5 of 20 (25%) patients. Conclusions: The study of lymphatic drainage can contribute to a better knowledge of the in vivo potential pattern of lymph node metastasis in prostate cancer and can lead to a modification of treatment volume with consequent optimization of pelvic irradiation.« less

Prognostic evaluation in obese patients using a dedicated multipinhole cadmium-zinc telluride SPECT camera.

PubMed

De Lorenzo, Andrea; Peclat, Thais; Amaral, Ana Carolina; Lima, Ronaldo S L

2016-02-01

The purpose of this study is to evaluate the prognostic value of myocardial perfusion SPECT obtained in CZT cameras (CZT-SPECT) with multipinhole collimation in obese patients. CZT-SPECT may be technically challenging in the obese, and its prognostic value remains largely unknown. Patients underwent single-day, rest/stress (supine and prone) imaging. Images were visually inspected and graded as poor, fair or good/excellent. Summed stress and difference scores (SSS and SDS, respectively) were converted into percentages of total perfusion defect and of ischemic defect by division by the maximum possible score. Obesity was defined as a body mass index (BMI) ≥ 30 kg/m(2) and classified as class I (BMI 30-34.9 kg/m(2)), II (BMI 35-39.9 kg/m(2)), or III (BMI ≥ 40 kg/m(2)). Patients were followed-up by telephone interview for the occurrence of all-cause death, myocardial infarction or revascularization. A Cox proportional hazards analysis was used to assess the independent predictors of death. Among 1396 patients, 365 (26.1 %) were obese (mean BMI 33.9 ± 3.6; 17.5 % class I, 3.4 % class II, and 3.4 % class III). Image quality was good/excellent in 94.5 % of the obese patients. The annualized mortality rates were not significantly different among obese and non-obese patients, being <1 % with normal CZT-SPECT, and increased with the degree of scan abnormality in both obese and non-obese patients. Age, the use of pharmacologic stress and an abnormal CZT-SPECT, but not obesity, were independent predictors of death. In obese patients, single-day rest/stress CZT-SPECT with a multipinhole camera provides prognostic discrimination with high image quality.

SPECT Myocardial Blood Flow Quantitation Concludes Equivocal Myocardial Perfusion SPECT Studies to Increase Diagnostic Benefits.

PubMed

Chen, Lung-Ching; Lin, Chih-Yuan; Chen, Ing-Jou; Ku, Chi-Tai; Chen, Yen-Kung; Hsu, Bailing

2016-01-01

Recently, myocardial blood flow quantitation with dynamic SPECT/CT has been reported to enhance the detection of coronary artery disease in human. This advance has created important clinical applications to coronary artery disease diagnosis and management for areas where myocardial perfusion PET tracers are not available. We present 2 clinical cases that undergone a combined test of 1-day rest/dipyridamole-stress dynamic SPECT and ECG-gated myocardial perfusion SPECT scans using an integrated imaging protocol and demonstrate that flow parameters are capable to conclude equivocal myocardial perfusion SPECT studies, therefore increasing diagnostic benefits to add value in making clinical decisions.

Cardiac SPECT/CCTA hybrid imaging : One answer to two questions?

PubMed

Kaufmann, P A; Buechel, R R

2016-08-01

Noninvasive cardiac imaging has witnessed tremendous advances in the recent past, particularly with regard to coronary computed tomography angiography (CCTA) where substantial improvements in image quality have been achieved while at the same time patients' radiation dose exposure has been reduced to the sub-millisievert range. Similarly, for single-photon emission computed tomography (SPECT) the introduction of novel cadmium-zinc-telluride-based semiconductor detectors has significantly improved system sensitivity and image quality, enabling fast image acquisition within less than 2-3 min or reduction of radiation dose exposure to less than 5 mSv. However, neither imaging modality alone is able to fully cover the two aspects of coronary artery disease (CAD), that is, morphology and function. Both modalities have distinct advantages and shortcomings: While CCTA may prove a superb modality for excluding CAD through its excellent negative predictive value, it does not allow for assessment of hemodynamic relevance if obstructive coronary lesions are detected. Conversely, SPECT myocardial perfusion imaging cannot provide any information on the presence or absence of subclinical coronary atherosclerosis. This article aims to highlight the great potential of cardiac hybrid imaging that allows for a comprehensive evaluation of CAD through combination of both morphological and functional information by fusing SPECT with CCTA.

Wireless Synchronization of a Multi-Pinhole Small Animal SPECT Collimation Device With a Clinical Scanner

NASA Astrophysics Data System (ADS)

DiFilippo, Frank P.; Patel, Sagar

2009-06-01

A multi-pinhole collimation device for small animal single photon emission computed tomography (SPECT) uses the gamma camera detectors of a standard clinical SPECT scanner. The collimator and animal bed move independently of the detectors, and therefore their motions must be synchronized. One approach is manual triggering of the SPECT acquisition simultaneously with a programmed motion sequence for the device. However, some data blurring and loss of image quality result, and true electronic synchronization is preferred. An off-the-shelf digital gyroscope with integrated Bluetooth interface provides a wireless solution to device synchronization. The sensor attaches to the SPECT gantry and reports its rotational speed to a notebook computer controlling the device. Software processes the rotation data in real-time, averaging the signal and issuing triggers while compensating for baseline drift. Motion commands are sent to the collimation device with minimal delay, within approximately 0.5 second of the start of SPECT gantry rotation. Test scans of a point source demonstrate an increase in true counts and a reduction in background counts compared to manual synchronization. The wireless rotation sensor provides robust synchronization of the collimation device with the clinical SPECT scanner and enhances image quality.

High-throughput high-volume nuclear imaging for preclinical in vivo compound screening§.

PubMed

Macholl, Sven; Finucane, Ciara M; Hesterman, Jacob; Mather, Stephen J; Pauplis, Rachel; Scully, Deirdre; Sosabowski, Jane K; Jouannot, Erwan

2017-12-01

Preclinical single-photon emission computed tomography (SPECT)/CT imaging studies are hampered by low throughput, hence are found typically within small volume feasibility studies. Here, imaging and image analysis procedures are presented that allow profiling of a large volume of radiolabelled compounds within a reasonably short total study time. Particular emphasis was put on quality control (QC) and on fast and unbiased image analysis. 2-3 His-tagged proteins were simultaneously radiolabelled by 99m Tc-tricarbonyl methodology and injected intravenously (20 nmol/kg; 100 MBq; n = 3) into patient-derived xenograft (PDX) mouse models. Whole-body SPECT/CT images of 3 mice simultaneously were acquired 1, 4, and 24 h post-injection, extended to 48 h and/or by 0-2 h dynamic SPECT for pre-selected compounds. Organ uptake was quantified by automated multi-atlas and manual segmentations. Data were plotted automatically, quality controlled and stored on a collaborative image management platform. Ex vivo uptake data were collected semi-automatically and analysis performed as for imaging data. >500 single animal SPECT images were acquired for 25 proteins over 5 weeks, eventually generating >3500 ROI and >1000 items of tissue data. SPECT/CT images clearly visualized uptake in tumour and other tissues even at 48 h post-injection. Intersubject uptake variability was typically 13% (coefficient of variation, COV). Imaging results correlated well with ex vivo data. The large data set of tumour, background and systemic uptake/clearance data from 75 mice for 25 compounds allows identification of compounds of interest. The number of animals required was reduced considerably by longitudinal imaging compared to dissection experiments. All experimental work and analyses were accomplished within 3 months expected to be compatible with drug development programmes. QC along all workflow steps, blinding of the imaging contract research organization to compound properties and automation provide confidence in the data set. Additional ex vivo data were useful as a control but could be omitted from future studies in the same centre. For even larger compound libraries, radiolabelling could be expedited and the number of imaging time points adapted to increase weekly throughput. Multi-atlas segmentation could be expanded via SPECT/MRI; however, this would require an MRI-compatible mouse hotel. Finally, analysis of nuclear images of radiopharmaceuticals in clinical trials may benefit from the automated analysis procedures developed.

A Prototype Instrument for Adaptive SPECT Imaging

PubMed Central

Freed, Melanie; Kupinski, Matthew A.; Furenlid, Lars R.; Barrett, Harrison H.

2015-01-01

We have designed and constructed a small-animal adaptive SPECT imaging system as a prototype for quantifying the potential benefit of adaptive SPECT imaging over the traditional fixed geometry approach. The optical design of the system is based on filling the detector with the object for each viewing angle, maximizing the sensitivity, and optimizing the resolution in the projection images. Additional feedback rules for determining the optimal geometry of the system can be easily added to the existing control software. Preliminary data have been taken of a phantom with a small, hot, offset lesion in a flat background in both adaptive and fixed geometry modes. Comparison of the predicted system behavior with the actual system behavior is presented along with recommendations for system improvements. PMID:26346820

Radioactive Nanomaterials for Multimodality Imaging

PubMed Central

Chen, Daiqin; Dougherty, Casey A.; Yang, Dongzhi; Wu, Hongwei; Hong, Hao

2016-01-01

Nuclear imaging techniques, including primarily positron emission tomography (PET) and single-photon emission computed tomography (SPECT), can provide quantitative information for a biological event in vivo with ultra-high sensitivity, however, the comparatively low spatial resolution is their major limitation in clinical application. By convergence of nuclear imaging with other imaging modalities like computed tomography (CT), magnetic resonance imaging (MRI) and optical imaging, the hybrid imaging platforms can overcome the limitations from each individual imaging technique. Possessing versatile chemical linking ability and good cargo-loading capacity, radioactive nanomaterials can serve as ideal imaging contrast agents. In this review, we provide a brief overview about current state-of-the-art applications of radioactive nanomaterials in the circumstances of multimodality imaging. We present strategies for incorporation of radioisotope(s) into nanomaterials along with applications of radioactive nanomaterials in multimodal imaging. Advantages and limitations of radioactive nanomaterials for multimodal imaging applications are discussed. Finally, a future perspective of possible radioactive nanomaterial utilization is presented for improving diagnosis and patient management in a variety of diseases. PMID:27227167

Evaluating the effect of a third-party implementation of resolution recovery on the quality of SPECT bone scan imaging using visual grading regression.

PubMed

Hay, Peter D; Smith, Julie; O'Connor, Richard A

2016-02-01

The aim of this study was to evaluate the benefits to SPECT bone scan image quality when applying resolution recovery (RR) during image reconstruction using software provided by a third-party supplier. Bone SPECT data from 90 clinical studies were reconstructed retrospectively using software supplied independent of the gamma camera manufacturer. The current clinical datasets contain 120×10 s projections and are reconstructed using an iterative method with a Butterworth postfilter. Five further reconstructions were created with the following characteristics: 10 s projections with a Butterworth postfilter (to assess intraobserver variation); 10 s projections with a Gaussian postfilter with and without RR; and 5 s projections with a Gaussian postfilter with and without RR. Two expert observers were asked to rate image quality on a five-point scale relative to our current clinical reconstruction. Datasets were anonymized and presented in random order. The benefits of RR on image scores were evaluated using ordinal logistic regression (visual grading regression). The application of RR during reconstruction increased the probability of both observers of scoring image quality as better than the current clinical reconstruction even where the dataset contained half the normal counts. Type of reconstruction and observer were both statistically significant variables in the ordinal logistic regression model. Visual grading regression was found to be a useful method for validating the local introduction of technological developments in nuclear medicine imaging. RR, as implemented by the independent software supplier, improved bone SPECT image quality when applied during image reconstruction. In the majority of clinical cases, acquisition times for bone SPECT intended for the purposes of localization can safely be halved (from 10 s projections to 5 s) when RR is applied.

Objective evaluation of reconstruction methods for quantitative SPECT imaging in the absence of ground truth.

PubMed

Jha, Abhinav K; Song, Na; Caffo, Brian; Frey, Eric C

2015-04-13

Quantitative single-photon emission computed tomography (SPECT) imaging is emerging as an important tool in clinical studies and biomedical research. There is thus a need for optimization and evaluation of systems and algorithms that are being developed for quantitative SPECT imaging. An appropriate objective method to evaluate these systems is by comparing their performance in the end task that is required in quantitative SPECT imaging, such as estimating the mean activity concentration in a volume of interest (VOI) in a patient image. This objective evaluation can be performed if the true value of the estimated parameter is known, i.e. we have a gold standard. However, very rarely is this gold standard known in human studies. Thus, no-gold-standard techniques to optimize and evaluate systems and algorithms in the absence of gold standard are required. In this work, we developed a no-gold-standard technique to objectively evaluate reconstruction methods used in quantitative SPECT when the parameter to be estimated is the mean activity concentration in a VOI. We studied the performance of the technique with realistic simulated image data generated from an object database consisting of five phantom anatomies with all possible combinations of five sets of organ uptakes, where each anatomy consisted of eight different organ VOIs. Results indicate that the method provided accurate ranking of the reconstruction methods. We also demonstrated the application of consistency checks to test the no-gold-standard output.

Use of quantitative SPECT/CT reconstruction in 99mTc-sestamibi imaging of patients with renal masses.

PubMed

Jones, Krystyna M; Solnes, Lilja B; Rowe, Steven P; Gorin, Michael A; Sheikhbahaei, Sara; Fung, George; Frey, Eric C; Allaf, Mohamad E; Du, Yong; Javadi, Mehrbod S

2018-02-01

Technetium-99m ( 99m Tc)-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has previously been shown to allow for the accurate differentiation of benign renal oncocytomas and hybrid oncocytic/chromophobe tumors (HOCTs) apart from other malignant renal tumor histologies, with oncocytomas/HOCTs showing high uptake and renal cell carcinoma (RCC) showing low uptake based on uptake ratios from non-quantitative single-photon emission computed tomography (SPECT) reconstructions. However, in this study, several tumors fell close to the uptake ratio cutoff, likely due to limitations in conventional SPECT/CT reconstruction methods. We hypothesized that application of quantitative SPECT/CT (QSPECT) reconstruction methods developed by our group would provide more robust separation of hot and cold lesions, serving as an imaging framework on which quantitative biomarkers can be validated for evaluation of renal masses with 99m Tc-sestamibi. Single-photon emission computed tomography data were reconstructed using the clinical Flash 3D reconstruction and QSPECT methods. Two blinded readers then characterized each tumor as hot or cold. Semi-quantitative uptake ratios were calculated by dividing lesion activity by background renal activity for both Flash 3D and QSPECT reconstructions. The difference between median (mean) hot and cold tumor uptake ratios measured 0.655 (0.73) with the QSPECT method and 0.624 (0.67) with the conventional method, resulting in increased separation between hot and cold tumors. Sub-analysis of 7 lesions near the separation point showed a higher absolute difference (0.16) between QPSECT and Flash 3D mean uptake ratios compared to the remaining lesions. Our finding of improved separation between uptake ratios of hot and cold lesions using QSPECT reconstruction lays the foundation for additional quantitative SPECT techniques such as SPECT-UV in the setting of renal 99m Tc-sestamibi and other SPECT/CT exams. With robust quantitative image reconstruction and biomarker analysis, there may be an expanded role for SPECT/CT imaging in renal masses and other pathologic conditions.

Bone and Gallium Single-Photon Emission Computed Tomography-Computed Tomography is Equivalent to Magnetic Resonance Imaging in the Diagnosis of Infectious Spondylodiscitis: A Retrospective Study.

PubMed

Tamm, Alexander S; Abele, Jonathan T

2017-02-01

Spondylodiscitis has historically been a difficult clinical diagnosis. Two imaging techniques that address this problem are magnetic resonance imaging (MRI) and combined bone ( 99m Tc-methylene diphosphonate) and gallium-67 single-photon emission computed tomography-computed tomography (SPECT-CT). Their accuracies have not been adequately compared. The purpose of this study is to compare the sensitivities and specificities of bone and gallium SPECT-CT and MRI in infectious spondylodiscitis. This retrospective study assessed all patients who underwent a bone or gallium SPECT-CT of the spine to assess for infectious spondylodiscitis from January 1, 2010, to May 2, 2012, at a single tertiary care centre. Thirty-four patients (23 men; average 62 ± 14 years of age) were included. The results of the bone or gallium SPECT-CT were compared against MRI for all patients in the cohort who underwent an MRI within 12 weeks of the SPECT-CT. A diagnosis of spondylodiscitis in the discharge summary was considered the reference standard, and was based on a combination of clinical scenario, response to therapy, imaging, or microbiology. Spondylodiscitis was diagnosed in 18 patients and excluded in 16. Bone or gallium SPECT-CT and MRI had similar (P > .05; κ = 0.74) sensitivities (0.94 vs 0.94), specificities (1.00 vs 1.00), positive predictive values (1.00 vs 1.00), negative predictive values (0.94 vs 0.80), and accuracies (0.97 vs 0.95) when compared to the reference standard. Although MRI remains the initial modality of choice in diagnosing spondylodiscitis, bone and gallium SPECT-CT appears diagnostically equivalent and should be considered a viable supplementary or alternative imaging modality particularly if there is contraindication or inaccessibility to MRI. Copyright © 2016 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Nuclear medicine in breast cancer diagnostics: Primary tumor and lymphatic metastasis

NASA Astrophysics Data System (ADS)

Sinilkin, I.; Medvedeva, A.; Chernov, V.; Slonimskaya, E.; Zelchan, R.; Bragina, O.

2017-09-01

The purpose of the study: to assess the possibility of using nuclear medicine techniques at the stages of diagnosis and treatment of breast cancer. Materials and Methods: The study included 290 patients with breast cancer and 70 patients with benign breast tumors. The study was used as a radiopharmaceutical 99mTc-MIBI, 199Tl for imaging tumors and colloid 99mTc-Aloteh for visualization sentinel lymph nodes (SLN), colloid was injected peritumoral in four points to 80 MBq one day prior to the planned operation. Results: The sensitivity of SPECT using both 99mTc-MIBI and 199Tl for breast cancer detection was shown to be rather high, being 98.5% and 98%, respectively. It should be noted that the sensitivity of SPECT in detection of small tumors (less than 1 cm in diameter) and multicentric tumors was not high irrespective of the radioisotope used (60% and 65% with 99mTc-MIBI and 65% and 59% with 199Tl, respectively). The difference in the sensitivity was found between 99mTc-MIBI and 199T for the detection of regional lymph node metastasis (91% vs 70%). SLN were detected in 31 patients. The most commonly SLN were defined in the axillary region of 96.7%. In 22 (70.9%) patients there was no metastasis SLN. The sensitivity of the method was 91.2%, specificity of 100%. Conclusion: The specificity of SPECT with 199Tl was higher than that with 99mTc-MIBI. The data obtained show that SPECT with 199Tl can be recommended for its use as an additional breast cancer detection method in cases when other imaging techniques and histological findings are not accurate enough. The clinical study of 99mTc-Aloteh, a new radiopharmaceutical agent, has shown that the studied colloid has high uptake level in SLN and can be successfully used for visualization of SLN in patients with breast cancer.

Simulating patient-specific heart shape and motion using SPECT perfusion images with the MCAT phantom

NASA Astrophysics Data System (ADS)

Faber, Tracy L.; Garcia, Ernest V.; Lalush, David S.; Segars, W. Paul; Tsui, Benjamin M.

2001-05-01

The spline-based Mathematical Cardiac Torso (MCAT) phantom is a realistic software simulation designed to simulate single photon emission computed tomographic (SPECT) data. It incorporates a heart model of known size and shape; thus, it is invaluable for measuring accuracy of acquisition, reconstruction, and post-processing routines. New functionality has been added by replacing the standard heart model with left ventricular (LV) epicaridal and endocardial surface points detected from actual patient SPECT perfusion studies. LV surfaces detected from standard post-processing quantitation programs are converted through interpolation in space and time into new B-spline models. Perfusion abnormalities are added to the model based on results of standard perfusion quantification. The new LV is translated and rotated to fit within existing atria and right ventricular models, which are scaled based on the size of the LV. Simulations were created for five different patients with myocardial infractions who had undergone SPECT perfusion imaging. Shape, size, and motion of the resulting activity map were compared visually to the original SPECT images. In all cases, size, shape and motion of simulated LVs matched well with the original images. Thus, realistic simulations with known physiologic and functional parameters can be created for evaluating efficacy of processing algorithms.

Usefulness and pitfalls of MAA SPECT/CT in identifying digestive extrahepatic uptake when planning liver radioembolization.

PubMed

Lenoir, Laurence; Edeline, Julien; Rolland, Yann; Pracht, Marc; Raoul, Jean-Luc; Ardisson, Valérie; Bourguet, Patrick; Clément, Bruno; Boucher, Eveline; Garin, Etienne

2012-05-01

Identifying gastroduodenal uptake of (99m)Tc-macroaggregated albumin (MAA), which is associated with an increased risk of ulcer disease, is a crucial part of the therapeutic management of patients undergoing radioembolization for liver tumours. Given this context, the use of MAA single photon emission computed tomography (SPECT)/CT may be essential, but the procedure has still not been thoroughly evaluated. The aim of this retrospective study was to determine the effectiveness of MAA SPECT/CT in identifying digestive extrahepatic uptake, while determining potential diagnostic pitfalls. Overall, 139 MAA SPECT/CT scans were performed on 103 patients with different hepatic tumour types. Patients were followed up for at least 6 months according to standard requirements. Digestive, or digestive-like, uptake other than free pertechnetate was identified in 5.7% of cases using planar imaging and in 36.6% of cases using SPECT/CT. Uptake sites identified by SPECT/CT included the gastroduodenal region (3.6%), gall bladder (12.2%), portal vein thrombosis (6.5%), hepatic artery (6.5%), coil embolization site (2.1%) as well as falciform artery (5.0%). For 2.1% of explorations, a coregistration error between SPECT and CT imaging could have led to a false diagnosis by erroneously attributing an uptake site to the stomach or gall bladder, when the uptake actually occurred in the liver. SPECT/CT is more efficacious than planar imaging in identifying digestive extrahepatic uptake sites, with extrahepatic uptake observed in one third of scans using the former procedure. However, more than half of the uptake sites in our study were vascular in nature, without therapeutic implications. The risk of coregistration errors must also be kept in mind.

Diagnostic test accuracy study of 18F-sodium fluoride PET/CT, 99mTc-labelled diphosphonate SPECT/CT, and planar bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer

PubMed Central

Fonager, Randi F; Zacho, Helle D; Langkilde, Niels C; Fledelius, Joan; Ejlersen, June A; Haarmark, Christian; Hendel, Helle W; Lange, Mine Benedicte; Jochumsen, Mads R; Mortensen, Jesper C; Petersen, Lars J

2017-01-01

The aim of this study was to prospectively compare planar, bone scan (BS) versus SPECT/CT and NaF PET/CT in detecting bone metastases in prostate cancer. Thirty-seven consecutive, newly diagnosed, prostate cancer patients with prostate specific antigen (PSA) levels ≥ 50 ng/mL and who were considered eligible for androgen-deprivation therapy (ADT) were included in this study. BS, SPECT/CT, and NaF PET/CT, were performed prior to treatment and were repeated after six months of ADT. Baseline images from each index test were independently read by two experienced readers. The reference standard was based on a consensus decision made by a multidisciplinary team on the basis of baseline and follow-up images of the index tests, the findings of the baseline index tests by the experienced readers, and any available imaging, biochemical, and clinical data, including the response to ADT. Twenty-seven (73%) of the 37 patients had bone metastases according to the reference standard. The sensitivities for BS, SPECT/CT and NaF PET/CT were 78%, 89%, and 89%, respectively, and the specificities were 90%, 100%, and 90%, respectively. The positive predictive values of BS, SPECT/CT and NaF PET/CT were 96%, 100%, and 96%, respectively, and the negative predictive values were 60%, 77% and 75%, respectively. No statistically significant difference among the three imaging modalities was observed. All three imaging modalities showed high sensitivity and specificity. NaF PET/CT and SPECT/CT showed numerically improved, but not statistically superior, sensitivity compared with BS in this limited and selected patient cohort. PMID:29181269

Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography

PubMed Central

Wong, Ka-Kit; Gandhi, Arpit; Viglianti, Benjamin L; Fig, Lorraine M; Rubello, Domenico; Gross, Milton D

2016-01-01

AIM: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders. METHODS: We performed MEDLINE and PubMed searches using the terms: “SPECT/CT”; “functional anatomic mapping”; “transmission emission tomography”; “parathyroid adenoma”; “thyroid cancer”; “neuroendocrine tumor”; “adrenal”; “pheochromocytoma”; “paraganglioma”; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology. RESULTS: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for 99mTc-sestamibi parathyroid scintigraphy and 99mTc-pertechnetate thyroid scintigraphy, 123I- or 131I-radioiodine for staging of differentiated thyroid carcinoma, 111In- and 99mTc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, 131I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and 123I- or 131I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma. CONCLUSION: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy from CT, translating to improved diagnostic accuracy and meaningful impact on patient care. PMID:27358692

Final Report for "Boron and Tin in Nuclear Medicien: The Development of Reactive Solid-State Reagents for PET and SPECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

George W. Kabalka

The research program was directed at the use of functionalized organometallic reagents that would rapidly react with radiolabeled agents generated by a medical cyclotron or reactor. The radioisotopes included fluorine-18, oxgygen-15, nitrogen-13, carbon-11 and iodine-123; all short lived nuclides of importantce in nuclear medicine imaging studies utilizing emission tomography techniques. The early studies led to the development of extensive new isotope incorporation chemistry. These studies validated the feasibility of using reactive intermediates, such as the organoboranes, and acted as a catalyst for others to investigate organometallic agents based on mercury, tin, and silicon. A large number of radiolabeling techniques andmore » radiopharmaceuticals were developed. These included agents for use in oncology, neurology, and metabolism. The research resulted in the generation of one hundred and one journal articles, eighty seven refereed published abstracts and forty one invited lectures. Thirteen postdoctoral students, fourteen graduate students, and twenty eight undergraduate students were trained in the scientific aspects of nuclear medicine imaging under the asupices of this grant.« less

CT-based attenuation and scatter correction compared with uniform attenuation correction in brain perfusion SPECT imaging for dementia

NASA Astrophysics Data System (ADS)

Gillen, Rebecca; Firbank, Michael J.; Lloyd, Jim; O'Brien, John T.

2015-09-01

This study investigated if the appearance and diagnostic accuracy of HMPAO brain perfusion SPECT images could be improved by using CT-based attenuation and scatter correction compared with the uniform attenuation correction method. A cohort of subjects who were clinically categorized as Alzheimer’s Disease (n=38 ), Dementia with Lewy Bodies (n=29 ) or healthy normal controls (n=30 ), underwent SPECT imaging with Tc-99m HMPAO and a separate CT scan. The SPECT images were processed using: (a) correction map derived from the subject’s CT scan or (b) the Chang uniform approximation for correction or (c) no attenuation correction. Images were visually inspected. The ratios between key regions of interest known to be affected or spared in each condition were calculated for each correction method, and the differences between these ratios were evaluated. The images produced using the different corrections were noted to be visually different. However, ROI analysis found similar statistically significant differences between control and dementia groups and between AD and DLB groups regardless of the correction map used. We did not identify an improvement in diagnostic accuracy in images which were corrected using CT-based attenuation and scatter correction, compared with those corrected using a uniform correction map.

[Diagnosis of myocardial infarction by cine MR imaging--a comparative study with thallium-201 myocardial SPECT].

PubMed

Shiozaki, H

1993-01-25

The usefulness of cine magnetic resonance (MR) imaging was evaluated in 41 patients with acute (4 cases), subacute (21 cases) and chronic (16 cases) myocardial infarctions on the basis of the findings of thallium-201 myocardial SPECT. The overall rate of diagnostic accordance between cine MR imaging and SPECT was 85.0% (408/480). It was highest at the middle of the left ventricle (89.0%, 146/164) and lowest at the base (82.7%, 129/156). Measurement of wall thickness using the images printed on films was possible in 87.1% of segments (418/480). There was a significant difference in end-diastolic wall thickness and %-thickening between the infarcted and non-infarcted sites except for the base of the left ventricle. However, diastolic wall thinning was not remarkable in acute cases of less than one week after onset. In these cases %-thickening may be useful. Partial volume averaging on MR imaging and the inaccuracy of SPECT findings at the base also made meaningful comparison difficult. The most important diagnostic findings of myocardial infarction on cine MR imaging were end-diastolic wall thinning and abnormal motion such as akinesis and dyskinesis. It is concluded that cine MR imaging is a useful noninvasive examination method for evaluating the status of cardiac function in myocardial infarction.

Multi-pinhole collimator design for small-object imaging with SiliSPECT: a high-resolution SPECT

NASA Astrophysics Data System (ADS)

Shokouhi, S.; Metzler, S. D.; Wilson, D. W.; Peterson, T. E.

2009-01-01

We have designed a multi-pinhole collimator for a dual-headed, stationary SPECT system that incorporates high-resolution silicon double-sided strip detectors. The compact camera design of our system enables imaging at source-collimator distances between 20 and 30 mm. Our analytical calculations show that using knife-edge pinholes with small-opening angles or cylindrically shaped pinholes in a focused, multi-pinhole configuration in combination with this camera geometry can generate narrow sensitivity profiles across the field of view that can be useful for imaging small objects at high sensitivity and resolution. The current prototype system uses two collimators each containing 127 cylindrically shaped pinholes that are focused toward a target volume. Our goal is imaging objects such as a mouse brain, which could find potential applications in molecular imaging.

Technetium-99m and rhenium-188 complexes with one and two pendant bisphosphonate groups for imaging arterial calcification.

PubMed

Bordoloi, Jayanta Kumar; Berry, David; Khan, Irfan Ullah; Sunassee, Kavitha; de Rosales, Rafael Torres Martin; Shanahan, Catherine; Blower, Philip J

2015-03-21

The first (99m)Tc and (188)Re complexes containing two pendant bisphosphonate groups have been synthesised, based on the mononuclear M(v) nitride core with two dithiocarbamate ligands each with a pendant bisphosphonate. The structural identity of the (99)Tc and stable rhenium analogues as uncharged, mononuclear nitridobis(dithiocarbamate) complexes was determined by electrospray mass spectrometry. The (99m)Tc complex showed greater affinity for synthetic and biological hydroxyapatite, and greater stability in biological media, than the well-known but poorly-characterised and inhomogeneous bone imaging agent (99m)Tc-MDP. It gave excellent SPECT images of both bone calcification (mice and rats) and vascular calcification (rat model), but the improved stability and the availability of two pendant bisphosphonate groups conferred no dramatic advantage in imaging over the conventional (99m)Tc-MDP agent in which the bisphosphonate group is bound directly to Tc. The (188)Re complex also showed preferential uptake in bone. These tracers and the biological model of vascular calcification offer the opportunity to study the biological interpretation and clinical potential of radionuclide imaging of vascular calcification and to deliver radionuclide therapy to bone metastases.

Y-90 SPECT ML image reconstruction with a new model for tissue-dependent bremsstrahlung production using CT information: a proof-of-concept study

NASA Astrophysics Data System (ADS)

Lim, Hongki; Fessler, Jeffrey A.; Wilderman, Scott J.; Brooks, Allen F.; Dewaraja, Yuni K.

2018-06-01

While the yield of positrons used in Y-90 PET is independent of tissue media, Y-90 SPECT imaging is complicated by the tissue dependence of bremsstrahlung photon generation. The probability of bremsstrahlung production is proportional to the square of the atomic number of the medium. Hence, the same amount of activity in different tissue regions of the body will produce different numbers of bremsstrahlung photons. Existing reconstruction methods disregard this tissue-dependency, potentially impacting both qualitative and quantitative imaging of heterogeneous regions of the body such as bone with marrow cavities. In this proof-of-concept study, we propose a new maximum-likelihood method that incorporates bremsstrahlung generation probabilities into the system matrix, enabling images of the desired Y-90 distribution to be reconstructed instead of the ‘bremsstrahlung distribution’ that is obtained with existing methods. The tissue-dependent probabilities are generated by Monte Carlo simulation while bone volume fractions for each SPECT voxel are obtained from co-registered CT. First, we demonstrate the tissue dependency in a SPECT/CT imaging experiment with Y-90 in bone equivalent solution and water. Visually, the proposed reconstruction approach better matched the true image and the Y-90 PET image than the standard bremsstrahlung reconstruction approach. An XCAT phantom simulation including bone and marrow regions also demonstrated better agreement with the true image using the proposed reconstruction method. Quantitatively, compared with the standard reconstruction, the new method improved estimation of the liquid bone:water activity concentration ratio by 40% in the SPECT measurement and the cortical bone:marrow activity concentration ratio by 58% in the XCAT simulation.

Clinical evaluation of reducing acquisition time on single-photon emission computed tomography image quality using proprietary resolution recovery software.

PubMed

Aldridge, Matthew D; Waddington, Wendy W; Dickson, John C; Prakash, Vineet; Ell, Peter J; Bomanji, Jamshed B

2013-11-01

A three-dimensional model-based resolution recovery (RR) reconstruction algorithm that compensates for collimator-detector response, resulting in an improvement in reconstructed spatial resolution and signal-to-noise ratio of single-photon emission computed tomography (SPECT) images, was tested. The software is said to retain image quality even with reduced acquisition time. Clinically, any improvement in patient throughput without loss of quality is to be welcomed. Furthermore, future restrictions in radiotracer supplies may add value to this type of data analysis. The aims of this study were to assess improvement in image quality using the software and to evaluate the potential of performing reduced time acquisitions for bone and parathyroid SPECT applications. Data acquisition was performed using the local standard SPECT/CT protocols for 99mTc-hydroxymethylene diphosphonate bone and 99mTc-methoxyisobutylisonitrile parathyroid SPECT imaging. The principal modification applied was the acquisition of an eight-frame gated data set acquired using an ECG simulator with a fixed signal as the trigger. This had the effect of partitioning the data such that the effect of reduced time acquisitions could be assessed without conferring additional scanning time on the patient. The set of summed data sets was then independently reconstructed using the RR software to permit a blinded assessment of the effect of acquired counts upon reconstructed image quality as adjudged by three experienced observers. Data sets reconstructed with the RR software were compared with the local standard processing protocols; filtered back-projection and ordered-subset expectation-maximization. Thirty SPECT studies were assessed (20 bone and 10 parathyroid). The images reconstructed with the RR algorithm showed improved image quality for both full-time and half-time acquisitions over local current processing protocols (P<0.05). The RR algorithm improved image quality compared with local processing protocols and has been introduced into routine clinical use. SPECT acquisitions are now acquired at half of the time previously required. The method of binning the data can be applied to any other camera system to evaluate the reduction in acquisition time for similar processes. The potential for dose reduction is also inherent with this approach.

Design and evaluation of a mobile bedside PET/SPECT imaging system

NASA Astrophysics Data System (ADS)

Studenski, Matthew Thomas

Patients confined to an intensive care unit, the emergency room, or a surgical suite are managed without nuclear medicine procedures such as positron emission tomography (PET) or single photon emission computed tomography (SPECT). These studies have diagnostic value which can greatly benefit the physician's treatment of the patient but require that the patient is moved to a scanner. This dissertation examines the feasibility of an economical PET/SPECT system that can be brought to the bedside of an immobile patient for imaging. We chose to focus on cardiac SPECT imaging including perfusion imaging using 99mTc tracers and viability imaging using 18F tracers first because of problems arising from positioning a detector beneath a patient's bed, a requirement for the opposed detector orientation in PET imaging. Second, SPECT imaging acquiring over the anterior 180 degrees of the patient results in reduced attenuation effects due to the heart's location in the anterior portion of the body. Four studies were done to assess the clinical feasibility of the mobile system; 1) the performance of the system was evaluated in SPECT mode at both 140 keV (99mTc tracers) and 511 keV (positron emitting tracers), 2) a dynamic cardiac phantom was used to develop and test image acquisition and processing methods for the system at both energies, 3) a high energy pinhole collimator was designed to reduce the effects of high energy photon penetration through the parallel hole collimator, and 4) we estimated the radiation dose to persons that would be in the vicinity of a patient to ensure that the effective dose is below the regulatory limit. With these studies, we show that the mobile system provides an economical means of bringing nuclear medicine to an immobile patient while staying below the regulatory dose limit to other persons. The system performed well at both 140 keV and 511 keV and provided viable images of a phantom myocardium at both energies. The system does not achieve the same sensitivity and spatial resolution as a dedicated system but performs well in detecting severe myocardial defects that would otherwise go undetected.

SU-C-201-06: Utility of Quantitative 3D SPECT/CT Imaging in Patient Specific Internal Dosimetry of 153-Samarium with GATE Monte Carlo Package

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fallahpoor, M; Abbasi, M; Sen, A

Purpose: Patient-specific 3-dimensional (3D) internal dosimetry in targeted radionuclide therapy is essential for efficient treatment. Two major steps to achieve reliable results are: 1) generating quantitative 3D images of radionuclide distribution and attenuation coefficients and 2) using a reliable method for dose calculation based on activity and attenuation map. In this research, internal dosimetry for 153-Samarium (153-Sm) was done by SPECT-CT images coupled GATE Monte Carlo package for internal dosimetry. Methods: A 50 years old woman with bone metastases from breast cancer was prescribed 153-Sm treatment (Gamma: 103keV and beta: 0.81MeV). A SPECT/CT scan was performed with the Siemens Simbia-Tmore » scanner. SPECT and CT images were registered using default registration software. SPECT quantification was achieved by compensating for all image degrading factors including body attenuation, Compton scattering and collimator-detector response (CDR). Triple energy window method was used to estimate and eliminate the scattered photons. Iterative ordered-subsets expectation maximization (OSEM) with correction for attenuation and distance-dependent CDR was used for image reconstruction. Bilinear energy mapping is used to convert Hounsfield units in CT image to attenuation map. Organ borders were defined by the itk-SNAP toolkit segmentation on CT image. GATE was then used for internal dose calculation. The Specific Absorbed Fractions (SAFs) and S-values were reported as MIRD schema. Results: The results showed that the largest SAFs and S-values are in osseous organs as expected. S-value for lung is the highest after spine that can be important in 153-Sm therapy. Conclusion: We presented the utility of SPECT-CT images and Monte Carlo for patient-specific dosimetry as a reliable and accurate method. It has several advantages over template-based methods or simplified dose estimation methods. With advent of high speed computers, Monte Carlo can be used for treatment planning on a day to day basis.« less

NIR-Cyanine Dye Linker: a Promising Candidate for Isochronic Fluorescence Imaging in Molecular Cancer Diagnostics and Therapy Monitoring.

PubMed

Komljenovic, Dorde; Wiessler, Manfred; Waldeck, Waldemar; Ehemann, Volker; Pipkorn, Ruediger; Schrenk, Hans-Hermann; Debus, Jürgen; Braun, Klaus

2016-01-01

Personalized anti-cancer medicine is boosted by the recent development of molecular diagnostics and molecularly targeted drugs requiring rapid and efficient ligation routes. Here, we present a novel approach to synthetize a conjugate able to act simultaneously as an imaging and as a chemotherapeutic agent by coupling functional peptides employing solid phase peptide synthesis technologies. Development and the first synthesis of a fluorescent dye with similarity in the polymethine part of the Cy7 molecule whose indolenine-N residues were substituted with a propylene linker are described. Methylating agent temozolomide is functionalized with a tetrazine as a diene component whereas Cy7-cell penetrating peptide conjugate acts as a dienophilic reaction partner for the inverse Diels-Alder click chemistry-mediated ligation route yielding a theranostic conjugate, 3-mercapto-propionic-cyclohexenyl-Cy7-bis-temozolomide-bromide-cell penetrating peptide. Synthesis route described here may facilitate targeted delivery of the therapeutic compound to achieve sufficient local concentrations at the target site or tissue. Its versatility allows a choice of adequate imaging tags applicable in e.g. PET, SPECT, CT, near-infrared imaging, and therapeutic substances including cytotoxic agents. Imaging tags and therapeutics may be simultaneously bound to the conjugate applying click chemistry. Theranostic compound presented here offers a solid basis for a further improvement of cancer management in a precise, patient-specific manner.

NIR-Cyanine Dye Linker: a Promising Candidate for Isochronic Fluorescence Imaging in Molecular Cancer Diagnostics and Therapy Monitoring

PubMed Central

Komljenovic, Dorde; Wiessler, Manfred; Waldeck, Waldemar; Ehemann, Volker; Pipkorn, Ruediger; Schrenk, Hans-Hermann; Debus, Jürgen; Braun, Klaus

2016-01-01

Personalized anti-cancer medicine is boosted by the recent development of molecular diagnostics and molecularly targeted drugs requiring rapid and efficient ligation routes. Here, we present a novel approach to synthetize a conjugate able to act simultaneously as an imaging and as a chemotherapeutic agent by coupling functional peptides employing solid phase peptide synthesis technologies. Development and the first synthesis of a fluorescent dye with similarity in the polymethine part of the Cy7 molecule whose indolenine-N residues were substituted with a propylene linker are described. Methylating agent temozolomide is functionalized with a tetrazine as a diene component whereas Cy7-cell penetrating peptide conjugate acts as a dienophilic reaction partner for the inverse Diels-Alder click chemistry-mediated ligation route yielding a theranostic conjugate, 3-mercapto-propionic-cyclohexenyl-Cy7-bis-temozolomide-bromide-cell penetrating peptide. Synthesis route described here may facilitate targeted delivery of the therapeutic compound to achieve sufficient local concentrations at the target site or tissue. Its versatility allows a choice of adequate imaging tags applicable in e.g. PET, SPECT, CT, near-infrared imaging, and therapeutic substances including cytotoxic agents. Imaging tags and therapeutics may be simultaneously bound to the conjugate applying click chemistry. Theranostic compound presented here offers a solid basis for a further improvement of cancer management in a precise, patient-specific manner. PMID:26722379

An overview of contemporary nuclear cardiology.

PubMed

Lewin, Howard C; Sciammarella, Maria G; Watters, Thomas A; Alexander, Herbert G

2004-01-01

Myocardial perfusion single photon emission computed tomography (SPECT) is a widely utilized noninvasive imaging modality for the diagnosis, prognosis, and risk stratification of coronary artery disease. It is clearly superior to the traditional planar technique in terms of imaging contrast and consequent diagnostic and prognostic yield. The strength of SPECT images is largely derived from the three-dimensional, volumetric nature of its image. Thus, this modality permits three-dimensional assessment and quantitation of the perfused myocardium and functional assessment through electrocardiographic gating of the perfusion images.

Gender differences in the diagnostic accuracy of SPECT myocardial perfusion imaging: a bivariate meta-analysis.

PubMed

Iskandar, Aline; Limone, Brendan; Parker, Matthew W; Perugini, Andrew; Kim, Hyejin; Jones, Charles; Calamari, Brian; Coleman, Craig I; Heller, Gary V

2013-02-01

It remains controversial whether the diagnostic accuracy of single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) is different in men as compared to women. We performed a meta-analysis to investigate gender differences of SPECT MPI for the diagnosis of CAD (≥50% stenosis). Two investigators independently performed a systematic review of the MEDLINE and EMBASE databases from inception through January 2012 for English-language studies determining the diagnostic accuracy of SPECT MPI. We included prospective studies that compared SPECT MPI with conventional coronary angiography which provided sufficient data to calculate gender-specific true and false positives and negatives. Data from studies evaluating <20 patients of one gender were excluded. Bivariate meta-analysis was used to create summary receiver operating curves. Twenty-six studies met inclusion criteria, representing 1,148 women and 1,142 men. Bivariate meta-analysis yielded a mean sensitivity and specificity of 84.2% (95% confidence interval [CI] 78.7%-88.6%) and 78.7% (CI 70.0%-85.3%) for SPECT MPI in women and 89.1% (CI 84.0%-92.7%) and 71.2% (CI 60.8%-79.8%) for SPECT MPI in men. There was no significant difference in the sensitivity (P = .15) or specificity (P = .23) between male and female subjects. In a bivariate meta-analysis of the available literature, the diagnostic accuracy of SPECT MPI is similar for both men and women.

Differences in serotonin transporter binding affinity in patients with major depressive disorder and night eating syndrome.

PubMed

Lundgren, J D; Amsterdam, J; Newberg, A; Allison, K C; Wintering, N; Stunkard, A J

2009-03-01

We examined serotonin transporter (SERT) binding affinity using single photon emission computed tomography (SPECT) in patients with major depressive disorder (MDD) and night eating syndrome (NES). There are similarities between MDD and NES in affective symptoms, appetite disturbance, nighttime awakenings, and, particularly, response to selective serotonin reuptake inhibitors (SSRIs). Six non-depressed patients with NES and seven patients with MDD underwent SPECT brain imaging with 123I-ADAM, a radiopharmaceutical agent selective for SERT sites. Uptake ratios of 123I-ADAM SERT binding were obtained for the midbrain, basal ganglia, and temporal lobe regions compared to the cerebellum reference region. Patients with NES had significantly greater SERT uptake ratios (effect size range 0.64-0.84) in the midbrain, right temporal lobe, and left temporal lobe regions than those with MDD whom we had previously studied. Pathophysiological differences in SERT uptake between patients with NES and MDD suggest these are distinct clinical syndromes.

Functional mechanism of lung mosaic CT attenuation: assessment with deep-inspiration breath-hold perfusion SPECT-CT fusion imaging and non-breath-hold Technegas SPECT.

PubMed

Suga, K; Yasuhiko, K; Iwanaga, H; Tokuda, O; Matsunaga, N

2009-01-01

The functional mechanism of lung mosaic computed tomography attenuation (MCA) in pulmonary vascular disease (PVD) and obstructive airway disease (OAD) has not yet been fully clarified. To clarify the mechanism of MCA in these diseases by assessing the relationship between regional lung function and CT attenuation change at MCA sites with the use of automated deep-inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images and non-breath-hold Technegas SPECT. Subjects were 42 PVD patients (31 pulmonary thromboembolism, four primary/two secondary pulmonary hypertension, and five Takayasu arteritis), 12 OAD patients (five acute asthma, four obliterative bronchiolitis, and three bronchiectasis), and 12 normal controls, all of whom had MCA on DIBrH CT. The relationship between regional lung function and CT attenuation change at the lung slices with MCA was assessed using DIBrH perfusion SPECT-CT fusion images and non-breath-hold Technegas SPECT. The severity of perfusion defects with or without MCA was quantified by regions-of-interest analysis. On DIBrH CT and perfusion SPECT, in contrast to no noticeable CT attenuation abnormality and fairly uniform perfusion in controls, 60 MCA and 274 perfusion defects in PVD patients, and 18 MCA and 61 defects in OAD patients were identified, with a total of 77 ventilation defects on Technegas SPECT in all patients. SPECT-CT correlation showed that, throughout the 78 MCA sites of all patients, lung perfusion was persistently decreased at low CT attenuation and preserved at intervening high CT attenuation, while lung ventilation was poorly correlated with CT attenuation change. The radioactivity ratios of reduced perfusion and the intervening preserved perfusion at the 78 perfusion defects with MCA were significantly lower than those at the remaining 257 defects without MCA (P<0.0001). Although further validation is required, our results indicate that heterogeneous pulmonary arterial perfusion may be a dominant mechanism of MCA in PVD and OAD.

Assessment of Treatment Response by 99mTc-MIP-1404 SPECT/CT: A Pilot Study in Patients With Metastatic Prostate Cancer.

PubMed

Schmidkonz, Christian; Cordes, Michael; Beck, Michael; Goetz, Theresa Ida; Schmidt, Daniela; Prante, Olaf; Bäuerle, Tobias; Cavallaro, Alexander; Uder, Michael; Wullich, Bernd; Goebell, Peter; Kuwert, Torsten; Ritt, Philipp

2018-06-19

We investigated the role of Tc-MIP-1404 (Progenics Pharmaceuticals, Inc, New York, NY) SPECT/CT of PSMA expression in the assessment of treatment response in patients with metastatic prostate cancer. We retrospectively analyzed Tc-MIP-1404 SPECT/CT scans from 28 patients with metastatic prostate cancer examined before initiation and after completion of therapy. Eight of these patients had been treated with androgen deprivation therapy, 10 with docetaxel, and another 10 with external beam radiotherapy. On the CT images from SPECT/CT, treatment response was assessed according to RECIST 1.1 criteria; independently from that analysis, maximal standardized uptake values (SUVmax) were quantified in representative tumor lesions and treatment response assumed at differences in SUVmax greater than 30%. Radiographic response assessment was correlated to biochemical response (BR) based on prostate-specific antigen serum levels. The concordance rate between SPECT and BR was 75% (95% confidence interval [CI], 0.55-0.89) (Cohen κ = 0.57; 95% CI, 0.29-0.85; P ≤ 0.01), higher than for that between SPECT and CT with 57% (95% CI, 0.37-0.76) (κ = 0.40; 95% CI, 0.14-0.65; P ≤ 0.01), as well as that between CT and BR with 50% (95% CI, 0.31-0.69) (κ = 0.31; 95% CI, 0.06-0.57, P ≤ 0.05). Discordant findings between SPECT and CT were most likely due to limitations of CT in assessing metastases in lymph nodes, as well as bone involvement, which was sometimes not detectable on CT scans. The high agreement between treatment response, as assessed by Tc-MIP-1404 SPECT/CT and BR, suggests a possible role of that imaging tool for monitoring treatment in metastatic prostate cancer. Larger, ideally prospective trials are needed to help to reveal the full potential of SPECT imaging of PSMA expression in that regard.

Correlative studies of structural and functional imaging in primary progressive aphasia.

PubMed

Panegyres, P K; McCarthy, M; Campbell, A; Lenzo, N; Fallon, M; Thompson, J

2008-01-01

To compare and contrast structural and functional imaging in primary progressive aphasia (PPA). A cohort of 8 patients diagnosed with PPA presenting with nonfluency were prospectively evaluated. All patients had structural imaging in the form of MRI and in 1 patient CAT scanning on account of a cardiac pacemaker. All patients had single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging. SPECT and PET imaging had 100% correlation. Anatomical imaging was abnormal in only 6 of the 8 patients. Wernicke's area showed greater peak Z score reduction and extent of area affected than Broca's area (McNemar paired test: P = .008 for Z score reduction; P = .0003 for extent). PET scanning revealed significant involvement of the anterior cingulum. Functional imaging in PPA: (a) identified more patients correctly than anatomic imaging highlighting the importance of SPECT and PET in the diagnosis; and (b) demonstrated the heterogeneous involvement of disordered linguistic networks in PPA suggesting its syndromic nature.

Performance Evaluation of a Bedside Cardiac SPECT System

NASA Astrophysics Data System (ADS)

Studenski, Matthew T.; Gilland, David R.; Parker, Jason G.; Hammond, B.; Majewski, Stan; Weisenberger, Andrew G.; Popov, Vladimir

2009-06-01

This paper reports on the initial performance evaluation of a bedside cardiac PET/SPECT system. The system was designed to move within a hospital to image critically-ill patients, for example, those in intensive care unit (ICU) or emergency room settings, who cannot easily be transported to a conventional SPECT or PET facility. The system uses two compact (25 cm times 25 cm) detectors with pixilated NaI crystals and position sensitive PMTs. The performance is evaluated for both 140 keV (Tc-99m) and 511 keV (F-18) emitters with the system operating in single photon counting (SPECT) mode. The imaging performance metrics for both 140 keV and 511 keV included intrinsic energy resolution, spatial resolution (intrinsic, system, and reconstructed SPECT), detection sensitivity, count rate capability, and uniformity. Results demonstrated an intrinsic energy resolution of 31% at 140 keV and 23% at 511 keV, a planar intrinsic spatial resolution of 5.6 mm full width half-maximum (FWHM) at 140 keV and 6.3 mm FWHM at 511 keV, and a sensitivity of 4.15 countsmiddotmuCi-1 ldr s-1 at 140 keV and 0.67 counts ldr muCi-1 ldr s-1 at 511 keV. To further the study, a SPECT acquisition using a dynamic cardiac phantom was performed, and the resulting reconstructed images are presented.

Performance Evaluation of a Bedside Cardiac SPECT System

DOE Office of Scientific and Technical Information (OSTI.GOV)

M.T. Studenski, D.R. Gilland, J.G. Parker, B. Hammond, S. Majewski, A.G. Weisenberger, V. Popov

This paper reports on the initial performance evaluation of a bedside cardiac PET/SPECT system. The system was designed to move within a hospital to image critically-ill patients, for example, those in intensive care unit (ICU) or emergency room settings, who cannot easily be transported to a conventional SPECT or PET facility. The system uses two compact (25 cm times 25 cm) detectors with pixilated NaI crystals and position sensitive PMTs. The performance is evaluated for both 140 keV (Tc-99m) and 511 keV (F-18) emitters with the system operating in single photon counting (SPECT) mode. The imaging performance metrics for bothmore » 140 keV and 511 keV included intrinsic energy resolution, spatial resolution (intrinsic, system, and reconstructed SPECT), detection sensitivity, count rate capability, and uniformity. Results demonstrated an intrinsic energy resolution of 31% at 140 keV and 23% at 511 keV, a planar intrinsic spatial resolution of 5.6 mm full width half-maximum (FWHM) at 140 keV and 6.3 mm FWHM at 511 keV, and a sensitivity of 4.15 countsmiddotmuCi-1 ldr s-1 at 140 keV and 0.67 counts ldr muCi-1 ldr s-1 at 511 keV. To further the study, a SPECT acquisition using a dynamic cardiac phantom was performed, and the resulting reconstructed images are presented.« less

In vivo click reaction between Tc-99m-labeled azadibenzocyclooctyne-MAMA and 2-nitroimidazole-azide for tumor hypoxia targeting.

PubMed

Sun, Wenjing; Chu, Taiwei

2015-10-15

The bioactivity of nitroimidazole in Tc-99m-labeled 2-nitroimidazole, a traditional solid tumor hypoxia-imaging agent for single photon emission computed tomography (SPECT), is reduced by the presence of large ligand and metallic radionuclide, exhibiting lower tumor-to-nontumor ratios. In an effort to solve this general problem, a pretargeting strategy based on click chemistry (strain-promoted cyclooctyne-azide cycloaddition) was applied. The functional click synthons were synthesized as pretargeting components: an azide group linked to 2-nitroimidazole (2NIM-Az) serves for tumor hypoxia-targeting and azadibenzocyclooctyne conjugated with monoamine monoamide dithiol ligand (AM) functions as radiolabeling and binding group to azides in vivo. 2NIM-triazole-MAMA was obtained from in vitro click reaction with a reaction rate constant of 0.98M(-1)s(-1). AM and 2NIM-triazole-MAMA were radiolabeled with Tc-99m. The hypoxia-pretargeting biodistribution was studied in Kunming mice bearing S180 tumor; (99m)Tc-AM and (99m)Tc-triazole-2NIM were used as blank control and conventional control. Compared to the control groups, the pretargeting experiment exhibits the best radio-uptake and retention in tumor, with higher tumor-to-muscle and tumor-to-blood ratios (up to 8.55 and 1.44 at 8h post-(99m)Tc-complex-injection, respectively). To some extent, the pretargeting strategy protects the bioactivity of nitroimidazole and therefore provides an innovative approach for the development of tumor hypoxia-SPECT imaging agents. Copyright © 2015 Elsevier Ltd. All rights reserved.

A comparative study of brain perfusion single-photon emission computed tomography and magnetic resonance imaging in patients with post-traumatic anosmia.

PubMed

Atighechi, Saeid; Salari, Hadi; Baradarantar, Mohammad Hossein; Jafari, Rozita; Karimi, Ghasem; Mirjali, Mehdi

2009-01-01

Loss of smell is a problem that can occur in up to 30% of patients with head trauma. The olfactory function investigation methods so far in use have mostly relied on subjective responses given by patients. Recently, some studies have used magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) to evaluate patients with post-traumatic anosmia. The present study seeks to detect post-traumatic anosmia and the areas in the brain that are related to olfactory impairment by using SPECT and MRI as imaging techniques. The study was conducted on 21 patients suffering from head injury and consequently anosmia as defined by an olfactory identification test. Two control groups (traumatic normosmic and nontraumatic healthy individuals) were selected. Brain MRI, qualitative and semiquantitative SPECT with 99mtc-ethyl-cysteinate-dimer were taken from all the patients. Then the brain SPECT and MRI were compared with each other. Semi-quantitative assessment of the brain perfusion SPECT revealed frontal, left parietal, and left temporal hypoperfusion as compared with the two control groups. Eighty-five percent of the anosmic patients had abnormal brain MRI. Regarding the MRI, the main abnormality proved to be in the anterior inferior region of the frontal lobes and olfactory bulbs. The findings of this study suggest that damage to the frontal lobes and olfactory bulbs as shown in the brain MRI and hypoperfusion in the frontal, left parietal, and left temporal lobes in the semiquantitative SPECT corresponds to post-traumatic anosmia. Further neurophysiological and imaging studies are definitely needed to set the idea completely.

Ideal-observer analysis of lesion detectability in planar, conventional SPECT, and dedicated SPECT scintimammography using effective multi-dimensional smoothing

NASA Astrophysics Data System (ADS)

La Riviere, P. J.; Pan, X.; Penney, B. C.

1998-06-01

Scintimammography, a nuclear-medicine imaging technique that relies on the preferential uptake of Tc-99m-sestamibi and other radionuclides in breast malignancies, has the potential to provide differentiation of mammographically suspicious lesions, as well as outright detection of malignancies in women with radiographically dense breasts. In this work we use the ideal-observer framework to quantify the detectability of a 1-cm lesion using three different imaging geometries: the planar technique that is the current clinical standard, conventional single-photon emission computed tomography (SPECT), in which the scintillation cameras rotate around the entire torso, and dedicated breast SPECT, in which the cameras rotate around the breast alone. We also introduce an adaptive smoothing technique for the processing of planar images and of sinograms that exploits Fourier transforms to achieve effective multidimensional smoothing at a reasonable computational cost. For the detection of a 1-cm lesion with a clinically typical 6:1 tumor-background ratio, we find ideal-observer signal-to-noise ratios (SNR) that suggest that the dedicated breast SPECT geometry is the most effective of the three, and that the adaptive, two-dimensional smoothing technique should enhance lesion detectability in the tomographic reconstructions.

New Trends in Radionuclide Myocardial Perfusion Imaging

PubMed Central

Hung, Guang-Uei; Wang, Yuh-Feng; Su, Hung-Yi; Hsieh, Te-Chun; Ko, Chi-Lun; Yen, Ruoh-Fang

2016-01-01

Radionuclide myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) has been widely used clinically as one of the major functional imaging modalities for patients with coronary artery disease (CAD) for decades. Ample evidence has supported the use of MPI as a useful and important tool in the diagnosis, risk stratification and treatment planning for CAD. Although popular in the United States, MPI has become the most frequently used imaging modality among all nuclear medicine tests in Taiwan. However, it should be acknowledged that MPI SPECT does have its limitations. These include false-positive results due to certain artifacts, false-negative due to balanced ischemia, complexity and adverse reaction arising from current pharmacological stressors, time consuming nature of the imaging procedure, no blood flow quantitation and relatively high radiation exposure. The purpose of this article was to review the recent trends in nuclear cardiology, including the utilization of positron emission tomography (PET) for MPI, new stressor, new SPECT camera with higher resolution and higher sensitivity, dynamic SPECT protocol for blood flow quantitation, new software of phase analysis for evaluation of LV dyssynchrony, and measures utilized for reducing radiation exposure of MPI. PMID:27122946

CT-SPECT fusion plus conjugate views for determining dosimetry in iodine-131-monoclonal antibody therapy of lymphoma patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koral, K.F.; Zasadny, K.R.; Kessler, M.L.

A method of performing {sup 131}I quantitative SPECT imaging is described which uses the superimposition of markers placed on the skin to accomplish fusion of computed tomography (CT) and SPECT image sets. To calculate mean absorbed dose after administration of one of two {sup 131}I-labeled monoclonal antibodies (Mabs), the shape of the time-activity curve is measured by daily diagnostic conjugate views, the y-axis of that curve is normalized by a quantitative SPECT measurement (usually intra-therapy), and the tumor mass is deduced from a concurrent CT volume measurement. The method is applied to six B-cell non-Hodgkin`s lymphoma patients. For four tumorsmore » in three patients treated with the MB1 Mab, a correlation appears to be present between resulting mean absorbed dose and disease response. Including all dosimetric estimates for both antibodies, the range for the specific absorbed dose is within that found by others in treating B-cell lymphoma patients. Excluding a retreated anti-B1 patient, the tumor-specific absorbed dose during anti-B1 therapy is from 1.4 to 1.7 mGy/MBq. For the one anti-B1 patient, where quantitative SPECT and conjugate-view imaging was carried out back to back , the quantitative SPECT-measured activity was somewhat less for the spleen and much less for the tumor than that from conjugate views. The quantitative SPECT plus conjugate views method may be of general utility for macro-dosimetry of {sup 131}If therapies. 18 refs., 3 figs., 5 tabs.« less

SPECT-CT in routine clinical practice: increase in patient radiation dose compared with SPECT alone.

PubMed

Sharma, Punit; Sharma, Shekhar; Ballal, Sanjana; Bal, Chandrasekhar; Malhotra, Arun; Kumar, Rakesh

2012-09-01

To assess the patient radiation dose during routine clinical single-photon emission computed tomography-computed tomography (SPECT-CT) and measure the increase as compared with SPECT alone. Data pertaining to 357 consecutive patients who had undergone radioisotope imaging along with SPECT-CT of a selected volume were retrospectively evaluated. Dose of the injected radiopharmaceutical (MBq) was noted, and the effective dose (mSv) was calculated as per International Commission on Radiological Protection (ICRP) guidelines. The volume-weighted computed tomography dose index (CTDIvol) and dose length product of the CT were also assessed using standard phantoms. The effective dose (mSv) due to CT was calculated as the product of dose length product and a conversion factor depending on the region of investigation, using ICRP guidelines. The dose due to CT was compared among different investigations. The increase in effective dose was calculated as CT dose expressed as a percentage of radiopharmaceutical dose. The per-patient CT effective dose for different studies varied between 0.06 and 11.9 mSv. The mean CT effective dose was lowest for 99mTc-ethylene cysteine dimer brain SPECT-CT (0.9 ± 0.7) and highest for 99mTc-methylene diphosphonate bone SPECT-CT (4.2 ± 2.8). The increase in radiation dose (SPECT-CT vs. SPECT) varied widely (2.3-666.4% for 99mTc-tracers and 0.02-96.2% for 131I-tracers). However, the effective dose of CT in SPECT-CT was less than the values reported for conventional CT examinations of the same regions. Addition of CT to nuclear medicine imaging in the form of SPECT-CT increases the radiation dose to the patient, with the effective dose due to CT exceeding the effective dose of RP in many instances. Hence, appropriate utilization and optimization of the protocols of SPECT-CT is needed to maximize benefit to patients.

Dual-energy micro-CT imaging of pulmonary airway obstruction: correlation with micro-SPECT

NASA Astrophysics Data System (ADS)

Badea, C. T.; Befera, N.; Clark, D.; Qi, Y.; Johnson, G. A.

2014-03-01

To match recent clinical dual energy (DE) CT studies focusing on the lung, similar developments for DE micro-CT of the rodent lung are required. Our group has been actively engaged in designing pulmonary gating techniques for micro- CT, and has also introduced the first DE micro-CT imaging method of the rodent lung. The aim of this study was to assess the feasibility of DE micro-CT imaging for the evaluation of airway obstruction in mice, and to compare the method with micro single photon emission computed tomography (micro-SPECT) using technetium-99m labeled macroaggregated albumin (99mTc-MAA). The results suggest that the induced pulmonary airway obstruction causes either atelectasis, or air-trapping similar to asthma or chronic bronchitis. Atelectasis could only be detected at early time points in DE micro-CT images, and is associated with a large increase in blood fraction and decrease in air fraction. Air trapping had an opposite effect with larger air fraction and decreased blood fraction shown by DE micro-CT. The decrease in perfusion to the hypoventilated lung (hypoxic vasoconstriction) is also seen in micro-SPECT. The proposed DE micro-CT technique for imaging localized airway obstruction performed well in our evaluation, and provides a higher resolution compared to micro-SPECT. Both DE micro-CT and micro-SPECT provide critical, quantitative lung biomarkers for image-based anatomical and functional information in the small animal. The methods are readily linked to clinical methods allowing direct comparison of preclinical and clinical results.

5-HT Radioligands for Human Brain Imaging With PET and SPECT

PubMed Central

Paterson, Louise M.; Kornum, Birgitte R.; Nutt, David J.; Pike, Victor W.; Knudsen, Gitte M.

2014-01-01

The serotonergic system plays a key modulatory role in the brain and is the target for many drug treatments for brain disorders either through reuptake blockade or via interactions at the 14 subtypes of 5-HT receptors. This review provides the history and current status of radioligands used for positron emission tomography (PET) and single photon emission computerized tomography (SPECT) imaging of human brain serotonin (5-HT) receptors, the 5-HT transporter (SERT), and 5-HT synthesis rate. Currently available radioligands for in vivo brain imaging of the 5-HT system in humans include antagonists for the 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4 receptors, and for SERT. Here we describe the evolution of these radioligands, along with the attempts made to develop radioligands for additional serotonergic targets. We describe the properties needed for a radioligand to become successful and the main caveats. The success of a PET or SPECT radioligand can ultimately be assessed by its frequency of use, its utility in humans, and the number of research sites using it relative to its invention date, and so these aspects are also covered. In conclusion, the development of PET and SPECT radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to invaluable insight into normal and abnormal brain function, emphasizing the need for continued development of both SPECT and PET radioligands for human brain imaging. PMID:21674551

[Evaluation of left ventricular diastolic function using gated SPECT with 99mTc-MIBI].

PubMed

Toba, M; Kumita, S I; Mizumura, S; Cho, K; Kijima, T; Takahama, K; Kumazaki, T

1996-04-01

Development of 3 head SPECT system and 99mTc-labeled radiopharmaceuticals enable us to evaluate left ventricular systolic function on the basis of once gated SPECT routine. This study was focused on assessment of left ventricular diastolic function using 99mTc-MIBI gated SPECT data. Twenty nine patients with ischemic heart diseases underwent 99mTc-MIBI gated SPECT and 99mTc-HSAD ventriculographic assessment of left ventricular diastolic function within 1 month. Region of interests (ROI), simultaneously calculating counts per pixel within ROI, were placed over whole myocardium of 16 serial phasic images reconstructed from gated SPECT data, following selection of the central slice within short axial images. Then, 29 patients were classified into 3 patterns of phase count curve (normal, mixed, and delayed relaxation = diastolic dysfunction). Moreover, 1/3 Count Decreasing Fraction (1/3 CDF) was calculated on the same concept as 1/3 FF. The curve pattern showed significant differences between normal and abnormal group divided on the basis of established indices such as 1/3 FF and PFR, and 1/3 CDF has correlations with 1/3 FF (r = 0.61) and PFR (r = 0.58). We concluded that the new parameters drawn from 99mTc-MIBI gated SPECT data might be feasible for evaluation of diastolic function.

A Computer-Aided Analysis Method of SPECT Brain Images for Quantitative Treatment Monitoring: Performance Evaluations and Clinical Applications.

PubMed

Zheng, Xiujuan; Wei, Wentao; Huang, Qiu; Song, Shaoli; Wan, Jieqing; Huang, Gang

2017-01-01

The objective and quantitative analysis of longitudinal single photon emission computed tomography (SPECT) images are significant for the treatment monitoring of brain disorders. Therefore, a computer aided analysis (CAA) method is introduced to extract a change-rate map (CRM) as a parametric image for quantifying the changes of regional cerebral blood flow (rCBF) in longitudinal SPECT brain images. The performances of the CAA-CRM approach in treatment monitoring are evaluated by the computer simulations and clinical applications. The results of computer simulations show that the derived CRMs have high similarities with their ground truths when the lesion size is larger than system spatial resolution and the change rate is higher than 20%. In clinical applications, the CAA-CRM approach is used to assess the treatment of 50 patients with brain ischemia. The results demonstrate that CAA-CRM approach has a 93.4% accuracy of recovered region's localization. Moreover, the quantitative indexes of recovered regions derived from CRM are all significantly different among the groups and highly correlated with the experienced clinical diagnosis. In conclusion, the proposed CAA-CRM approach provides a convenient solution to generate a parametric image and derive the quantitative indexes from the longitudinal SPECT brain images for treatment monitoring.

SU-E-J-100: Reconstruction of Prompt Gamma Ray Three Dimensional SPECT Image From Boron Neutron Capture Therapy(BNCT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, D; Jung, J; Suh, T

2014-06-01

Purpose: Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography (SPECT) image from boron neutron capture therapy (BNCT) using Monte Carlo simulation. Methods: In case of simulation, the pixelated SPECT detector, collimator and phantom were simulated using Monte Carlo n particle extended (MCNPX) simulation tool. A thermal neutron source (<1 eV) was used to react with the boron uptake region (BUR) in the phantom. Each geometry had a spherical pattern, and three different BURs (A, B and C region, density: 2.08 g/cm3) were located in the middle of the brain phantom.more » The data from 128 projections for each sorting process were used to achieve image reconstruction. The ordered subset expectation maximization (OSEM) reconstruction algorithm was used to obtain a tomographic image with eight subsets and five iterations. The receiver operating characteristic (ROC) curve analysis was used to evaluate the geometric accuracy of reconstructed image. Results: The OSEM image was compared with the original phantom pattern image. The area under the curve (AUC) was calculated as the gross area under each ROC curve. The three calculated AUC values were 0.738 (A region), 0.623 (B region), and 0.817 (C region). The differences between length of centers of two boron regions and distance of maximum count points were 0.3 cm, 1.6 cm and 1.4 cm. Conclusion: The possibility of extracting a 3D BNCT SPECT image was confirmed using the Monte Carlo simulation and OSEM algorithm. The prospects for obtaining an actual BNCT SPECT image were estimated from the quality of the simulated image and the simulation conditions. When multiple tumor region should be treated using the BNCT, a reasonable model to determine how many useful images can be obtained from the SPECT could be provided to the BNCT facilities. This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, Information and Communication Technologies (ICT) and Future Planning (MSIP)(Grant No.200900420) and the Radiation Technology Research and Development program (Grant No.2013043498), Republic of Korea.« less

Correlation between clinical severity of central nervous system (CNS) lupus and findings on single photon emission computed tomographic (SPECT) images of the brain; preliminary results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverman, I.E.; Zeit, R.M.; Von Feldt, J.M.

1994-05-01

Systemic Lupus Erythematosis (SLE) commonly causes significant neuropsychiatric disorders. The purpose of this study was to review the brain SPECT studies of SLE patients with clinical evidence of CNS involvement and determine whether there is a correlation between the findings on SPECT images and the clinical manifestations of this serious phase of the disease. We enrolled 19 SLE patients and 12 normal controls in this study. The level of each patient`s disease activity was determined by the SLE Disease Activity Index (SLEDAI), an established method of scoring disease severity which is heavily weighted toward neuropsychiatric symptomatology, for 15 of themore » 19 SLE patients. The SLEDAI was calculated within a 10 day window of the date when the SPECT scan was obtained. SPECT scans were performed 30 minutes following the intravenous administration of 99mTc-HMPAO. Results are discussed.« less

New Mexico Center for Isotopes in Medicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burchiel, Scott W.

2012-12-13

The purpose of the New Mexico Center for Isotopes in Medicine (NMCIM) is to support research, education and service missions of the UNM College of Pharmacy Radiopharmaceutical Sciences Program (COP RSP) and the Cancer Research and Treatment Center (CRTC). NMCIM developed and coordinated unique translational research in cancer radioimaging and radiotherapy agents based on novel molecules developed at UNM and elsewhere. NMCIM was the primary interface for novel radioisotopes and radiochemistries developed at the Los Alamos National Laboratory (LANL) for SPECT/PET imaging and therapy. NMCIM coordinated the use of the small animal imaging facility with the CRTC provided support servicesmore » to assist investigators in their studies. NMCIM developed education and training programs that benefited professional, graduate, and postdoctoral students that utilized its unique facilities and technologies. UNM COP RSP has been active in writing research and training grants, as well as supporting contract research with industrial partners. The ultimate goal of NMCIM is to bring new radiopharmaceutical imaging and therapeutic agents into clinical trials that will benefit the health and well being of cancer and other patients in New Mexico and the U.S.« less

Synthesis, 99m Tc-labeling, and preliminary biological evaluation of DTPA-melphalan conjugates.

PubMed

Wang, Jianjun; Yang, Wenjiang; Xue, Jinquan; Zhang, Yanhua; Liu, Yu

2017-12-01

Melphalan (MFL) is a typical nitrogen mustard for the treatment of many types of cancer. For the purpose to develop novel 99m Tc-labeled tumor imaging agents with SPECT, MFL was directly labeled by 99m Tc using diethylene triamine pentacetate acid (DTPA) as bifunctional chelating agent. The novel ligands were successfully synthesized by conjugation of DTPA to MFL to get monosubstituted DTPA-MFL and bis-substituted DTPA-2MFL. Radiolabeling was performed in high yield to get 99m Tc-DTPA-MFL and 99m Tc-DTPA-2MFL, respectively, which were hydrophilic and stable at room temperature. The high initial tumor uptake with retention, good tumor/muscle ratios, and satisfactory scintigraphic images suggested the potential of 99m Tc-DTPA-MFL and 99m Tc-DTPA-2MFL for tumor imaging. However, the slow normal tissue clearance would be a great obstacle. Further modification on the linker and/or 99m Tc-chelate to improve the tumor targeting efficacy and in vivo kinetic profiles is currently in progress. Copyright © 2017 John Wiley & Sons, Ltd.

The effects of center of rotation errors on cardiac SPECT imaging

NASA Astrophysics Data System (ADS)

Bai, Chuanyong; Shao, Ling; Ye, Jinghan; Durbin, M.

2003-10-01

In SPECT imaging, center of rotation (COR) errors lead to the misalignment of projection data and can potentially degrade the quality of the reconstructed images. In this work, we study the effects of COR errors on cardiac SPECT imaging using simulation, point source, cardiac phantom, and patient studies. For simulation studies, we generate projection data using a uniform MCAT phantom first without modeling any physical effects (NPH), then with the modeling of detector response effect (DR) alone. We then corrupt the projection data with simulated sinusoid and step COR errors. For other studies, we introduce sinusoid COR errors to projection data acquired on SPECT systems. An OSEM algorithm is used for image reconstruction without detector response correction, but with nonuniform attenuation correction when needed. The simulation studies show that, when COR errors increase from 0 to 0.96 cm: 1) sinusoid COR errors in axial direction lead to intensity decrease in the inferoapical region; 2) step COR errors in axial direction lead to intensity decrease in the distal anterior region. The intensity decrease is more severe in images reconstructed from projection data with NPH than with DR; and 3) the effects of COR errors in transaxial direction seem to be insignificant. In other studies, COR errors slightly degrade point source resolution; COR errors of 0.64 cm or above introduce visible but insignificant nonuniformity in the images of uniform cardiac phantom; COR errors up to 0.96 cm in transaxial direction affect the lesion-to-background contrast (LBC) insignificantly in the images of cardiac phantom with defects, and COR errors up to 0.64 cm in axial direction only slightly decrease the LBC. For the patient studies with COR errors up to 0.96 cm, images have the same diagnostic/prognostic values as those without COR errors. This work suggests that COR errors of up to 0.64 cm are not likely to change the clinical applications of cardiac SPECT imaging when using iterative reconstruction algorithm without detector response correction.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Sui, E-mail: sshen@uabmc.edu; Jacob, Rojymon; Bender, Luvenia W.

Radiotherapy or stereotactic body radiosurgery (SBRT) requires a sufficient functional liver volume to tolerate the treatment. The current study extended the work of de Graaf et al. (2010) [3] on the use of {sup 99m}Tc-mebrofenin imaging for presurgery planning to radiotherapy planning for liver cancer or metastases. Patient was immobilized and imaged in an identical position on a single-photon emission computed tomography/computed tomography (SPECT-CT) system and a radiotherapy simulation CT system. {sup 99m}Tc-mebrofenin SPECT was registered to the planning CT through image registration of noncontrast CT from SPECT-CT system to the radiotherapy planning CT. The voxels with higher uptake ofmore » {sup 99m}Tc-mebrofenin were transferred to the planning CT as an avoidance structure in optimizing a 2-arc RapidArc plan for SBRT delivery. Excellent dose coverage to the target and sparing of the healthy remnant liver volume was achieved. This report illustrated a procedure for the use of {sup 99m}Tc-mebrofenin SPECT for optimizing radiotherapy for liver cancers and metastases.« less

A Silicon SPECT System for Molecular Imaging of the Mouse Brain.

PubMed

Shokouhi, Sepideh; Fritz, Mark A; McDonald, Benjamin S; Durko, Heather L; Furenlid, Lars R; Wilson, Donald W; Peterson, Todd E

2007-01-01

We previously demonstrated the feasibility of using silicon double-sided strip detectors (DSSDs) for SPECT imaging of the activity distribution of iodine-125 using a 300-micrometer thick detector. Based on this experience, we now have developed fully customized silicon DSSDs and associated readout electronics with the intent of developing a multi-pinhole SPECT system. Each DSSD has a 60.4 mm × 60.4 mm active area and is 1 mm thick. The strip pitch is 59 micrometers, and the readout of the 1024 strips on each side gives rise to a detector with over one million pixels. Combining four high-resolution DSSDs into a SPECT system offers an unprecedented space-bandwidth product for the imaging of single-photon emitters. The system consists of two camera heads with two silicon detectors stacked one behind the other in each head. The collimator has a focused pinhole system with cylindrical-shaped pinholes that are laser-drilled in a 250 μm tungsten plate. The unique ability to collect projection data at two magnifications simultaneously allows for multiplexed data at high resolution to be combined with lower magnification data with little or no multiplexing. With the current multi-pinhole collimator design, our SPECT system will be capable of offering high spatial resolution, sensitivity and angular sampling for small field-of-view applications, such as molecular imaging of the mouse brain.

The Diagnostic Efficiency of 99mTc-EDDA/HYNIC-Octreotate SPECT-CT in Comparison with 111In-Pentetrotide in the Detection of Neuroendocrine Tumours.

PubMed

Koçyiğit Deveci, Emel; Ocak, Meltem; Bozkurt, Murat Fani; Türker, Selcan; Kabasakal, Levent; Uğur, Omer

2013-12-01

The aim of this study was to assess the diagnostic efficiency of (99m)Tc-EDDA/HYNIC-Octreotate in comparison with (111)Inpentetrotide scintigraphy in the detection of neuroendocrine tumors. This study also evaluates the impact of SPECT-CT hybrid imaging on somatostatin receptor scintigraphy (SRS) interpretation and clinical management of these tumors. Fourteen patients were included in the study. All patients underwent a whole body and SPECT-CT imaging with both (99m)Tc- EDDA/HYNIC-octreotate and (111)In-pentetrotide. Images were evaluated both visually and semiquantitatively. On patient basis, the diagnostic results of both studies were similar. The number of lesions detected by (99m)Tc- EDDA/HYNICOctreotate were higher than the number of lesions detected by (111)In-pentetrotide however the difference was not significant (40/43( 93%), 36/43 (83%) p=0.109). Semiquantitative analysis showed higher tumor/organ count ratios for both whole-body and SPECT (99m)Tc- EDDA/HYNIC-Octreotate scans. The results of this study suggested that, (99m)Tc- EDDA/HYNIC-Octreotate may be a better alternative to (111)In- pentetrotide due to high image quality and lower radiation dose. SPECT/CT is a valuable tool for the assessment of neuroendocrine tumors by providing the precise anatomic localization of scintigraphic findings thus improving lesion detectability and characterization. None declared.

Experimental evaluation of radioiodinated sennoside B as a necrosis-avid tracer agent.

PubMed

Zhang, Dongjian; Huang, Dejian; Ji, Yun; Jiang, Cuihua; Li, Yue; Gao, Meng; Yao, Nan; Liu, Xuejiao; Shao, Haibo; Jing, Su; Ni, Yicheng; Yin, Zhiqi; Zhang, Jian

2015-02-01

Necrosis-avid agents are a class of compounds that selectively accumulate in the necrotic tissues after systemic administration, which can be used for in vivo necrosis imaging and targeted therapies. In order to search for a necrosis-avid tracer agent with improved drugability, we labelled iodine-131 on sennoside B (SB) as a naturally occurring median dianthrone compound. The necrosis targetability and clearance properties of (131)I-SB were evaluated in model rats with liver and muscle necrosis. On SPECT/CT images, a "hot spot" in the infarcted liver lobe and necrotic muscle was persistently observed at 24 h and 72 h post-injection (p.i.). Gamma counting of the tissues of interest revealed a radioactivity ratio of necrotic to viable liver at 4.6 and 3.4 and of necrotic to viable muscle at 7.0 and 8.8 at 24 h and 72 h p.i., respectively. The good match of autoradiographs and fluoromicroscopic images with corresponding histochemical staining suggested preferential uptake of (131)I-SB in necrotic tissue. Pharmacokinetic study revealed that (131)I-SB has an elimination half-life of 8.6 h. This study indicates that (131)I-SB shows not only prominent necrosis avidity but also favourable pharmacokinetics, which may serve as a potential necrosis-avid diagnostic agent for assessment of tissue viability.

Semi-Quantitative Analysis of Post-Transarterial Radioembolization (90)Y Microsphere Positron Emission Tomography Combined with Computed Tomography (PET/CT) Images in Advanced Liver Malignancy: Comparison With (99m)Tc Macroaggregated Albumin (MAA) Single Photon Emission Computed Tomography (SPECT).

PubMed

Rhee, Seunghong; Kim, Sungeun; Cho, Jaehyuk; Park, Jukyung; Eo, Jae Seon; Park, Soyeon; Lee, Eunsub; Kim, Yun Hwan; Choe, Jae-Gol

2016-03-01

The purpose of this study is to evaluate the correlation between pretreatment planning technetium-99m ((99m)Tc) macroaggregated albumin (MAA) SPECT images and posttreatment transarterial radioembolization (TARE) yttirum-90 ((90)Y) PET/CT images by comparing the ratios of tumor-to-normal liver counts. Fifty-two patients with advanced hepatic malignancy who underwent (90)Y microsphere radioembolization from January 2010 to December 2012 were retrospectively reviewed. Patients had undergone (99m)Tc MAA intraarterial injection SPECT for a pretreatment evaluation of microsphere distribution and therapy planning. After the administration of (90)Y microspheres, the patients underwent posttreatment (90)Y PET/CT within 24 h. For semiquantitative analysis, the tumor-to-normal uptake ratios in (90)Y PET/CT (TNR-yp) and (99m)Tc MAA SPECT (TNR-ms) as well as the tumor volumes measured in angiographic CT were obtained and analyzed. The relationship of TNR-yp and TNR-ms was evaluated by Spearman's rank correlation and Wilcoxon's matched pairs test. In a total of 79 lesions of 52 patients, the distribution of microspheres was well demonstrated in both the SPECT and PET/CT images. A good correlation was observed of between TNR-ms and TNR-yp (rho value = 0.648, p < 0.001). The TNR-yp (median 2.78, interquartile range 2.43) tend to show significantly higher values than TNR-ms (median 2.49, interquartile range of 1.55) (p = 0.012). The TNR-yp showed weak correlation with tumor volume (rho = 0.230, p = 0.041). The (99m)Tc MAA SPECT showed a good correlation with (90)Y PET/CT in TNR values, suggesting that (99m)Tc MAA can be used as an adequate pretreatment evaluation method. However, the (99m)Tc MAA SPECT image consistently shows lower TNR values compared to (90)Y PET/CT, which means the possibility of underestimation of tumorous uptake in the partition dosimetry model using (99m)Tc MAA SPECT. Considering that (99m)Tc MAA is the only clinically available surrogate marker for distribution of microsphere, we recommend measurement of tumorous uptake using (90)Y PET/CT should be included routinely in the posttherapeutic evaluation.

SPECT3D - A multi-dimensional collisional-radiative code for generating diagnostic signatures based on hydrodynamics and PIC simulation output

NASA Astrophysics Data System (ADS)

MacFarlane, J. J.; Golovkin, I. E.; Wang, P.; Woodruff, P. R.; Pereyra, N. A.

2007-05-01

SPECT3D is a multi-dimensional collisional-radiative code used to post-process the output from radiation-hydrodynamics (RH) and particle-in-cell (PIC) codes to generate diagnostic signatures (e.g. images, spectra) that can be compared directly with experimental measurements. This ability to post-process simulation code output plays a pivotal role in assessing the reliability of RH and PIC simulation codes and their physics models. SPECT3D has the capability to operate on plasmas in 1D, 2D, and 3D geometries. It computes a variety of diagnostic signatures that can be compared with experimental measurements, including: time-resolved and time-integrated spectra, space-resolved spectra and streaked spectra; filtered and monochromatic images; and X-ray diode signals. Simulated images and spectra can include the effects of backlighters, as well as the effects of instrumental broadening and time-gating. SPECT3D also includes a drilldown capability that shows where frequency-dependent radiation is emitted and absorbed as it propagates through the plasma towards the detector, thereby providing insights on where the radiation seen by a detector originates within the plasma. SPECT3D has the capability to model a variety of complex atomic and radiative processes that affect the radiation seen by imaging and spectral detectors in high energy density physics (HEDP) experiments. LTE (local thermodynamic equilibrium) or non-LTE atomic level populations can be computed for plasmas. Photoabsorption rates can be computed using either escape probability models or, for selected 1D and 2D geometries, multi-angle radiative transfer models. The effects of non-thermal (i.e. non-Maxwellian) electron distributions can also be included. To study the influence of energetic particles on spectra and images recorded in intense short-pulse laser experiments, the effects of both relativistic electrons and energetic proton beams can be simulated. SPECT3D is a user-friendly software package that runs on Windows, Linux, and Mac platforms. A parallel version of SPECT3D is supported for Linux clusters for large-scale calculations. We will discuss the major features of SPECT3D, and present example results from simulations and comparisons with experimental data.

Segmented slant hole collimator for stationary cardiac SPECT: Monte Carlo simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mao, Yanfei, E-mail: ymao@ucair.med.utah.edu; Yu, Zhicong; Zeng, Gengsheng L.

2015-09-15

Purpose: This work is a preliminary study of a stationary cardiac SPECT system. The goal of this research is to propose a stationary cardiac SPECT system using segmented slant-hole collimators and to perform computer simulations to test the feasibility. Compared to the rotational SPECT, a stationary system has a benefit of acquiring temporally consistent projections. The most challenging issue in building a stationary system is to provide sufficient projection view-angles. Methods: A GATE (GEANT4 application for tomographic emission) Monte Carlo model was developed to simulate a two-detector stationary cardiac SPECT that uses segmented slant-hole collimators. Each detector contains seven segmentedmore » slant-hole sections that slant to a common volume at the rotation center. Consequently, 14 view-angles over 180° were acquired without any gantry rotation. The NCAT phantom was used for data generation and a tailored maximum-likelihood expectation-maximization algorithm was used for image reconstruction. Effects of limited number of view-angles and data truncation were carefully evaluated in the paper. Results: Simulation results indicated that the proposed segmented slant-hole stationary cardiac SPECT system is able to acquire sufficient data for cardiac imaging without a loss of image quality, even when the uptakes in the liver and kidneys are high. Seven views are acquired simultaneously at each detector, leading to 5-fold sensitivity gain over the conventional dual-head system at the same total acquisition time, which in turn increases the signal-to-noise ratio by 19%. The segmented slant-hole SPECT system also showed a good performance in lesion detection. In our prototype system, a short hole-length was used to reduce the dead zone between neighboring collimator segments. The measured sensitivity gain is about 17-fold over the conventional dual-head system. Conclusions: The GATE Monte Carlo simulations confirm the feasibility of the proposed stationary cardiac SPECT system with segmented slant-hole collimators. The proposed collimator consists of combined parallel and slant holes, and the image on the detector is not reduced in size.« less

[Importance of parathyroid SPECT and 99mTc scintigraphy, and of clinical, laboratorial, ultrasonographic and citologic correlation in the pre-operative localization of the parathyroid adenoma - pictorial assay].

PubMed

Oliveira, Marco Antônio Condé de; Maeda, Sérgio Setsuo; Dreyer, Patrícia; Lobo, Alberto; Andrade, Victor Piana de; Hoff, Ana O; Biscolla, Rosa Paula Mello; Smanio, Paola; Brandão, Cynthia M A; Vieira, José G

2010-06-01

In patients with primary hyperparathyroidism, candidates for surgical intervention, the parathyroid pre-operative localization is of fundamental importance in planning the appropriate surgical approach. The additional acquisition of SPECT and Technetium-99m images, during parathyroid scintigraphy with Sestamibi, is not common practice. Usually, only planar image acquisition, 15 minutes prior and 2 hours after radiopharmaceutical administration, is performed. In our experience, the complete protocol in parathyroid scintigraphy increases the accuracy of pre-operative parathyroid localization. The complete utilization of all available nuclear medicine methods (SPECT e 99mTc) and image interpretation in a multidisciplinary context can improve the accuracy of parathyroid scintigraphy.

Hybrid SPECT/CT imaging in neurology.

PubMed

Ciarmiello, Andrea; Giovannini, Elisabetta; Meniconi, Martina; Cuccurullo, Vincenzo; Gaeta, Maria Chiara

2014-01-01

In recent years, the SPECT/CT hybrid modality has led to a rapid development of imaging techniques in nuclear medicine, opening new perspectives for imaging staff and patients as well. However, while, the clinical role of positron emission tomography-computed tomography (PET-CT) is well consolidated, the diffusion and the consequent value of single-photon emission tomography-computed tomography (SPECT-CT) has yet to be weighed, Hence, there is a need for a careful analysis, comparing the "potential" benefits of the hybrid modality with the "established" ones of the standalone machine. The aim of this article is to analyze the impact of this hybrid tool on the diagnosis of diseases of the central nervous system, comparing strengths and weaknesses of both modalities through the use of SWOT analysis.

Toward Quantitative Small Animal Pinhole SPECT: Assessment of Quantitation Accuracy Prior to Image Compensations

PubMed Central

Chen, Chia-Lin; Wang, Yuchuan; Lee, Jason J. S.; Tsui, Benjamin M. W.

2011-01-01

Purpose We assessed the quantitation accuracy of small animal pinhole single photon emission computed tomography (SPECT) under the current preclinical settings, where image compensations are not routinely applied. Procedures The effects of several common image-degrading factors and imaging parameters on quantitation accuracy were evaluated using Monte-Carlo simulation methods. Typical preclinical imaging configurations were modeled, and quantitative analyses were performed based on image reconstructions without compensating for attenuation, scatter, and limited system resolution. Results Using mouse-sized phantom studies as examples, attenuation effects alone degraded quantitation accuracy by up to −18% (Tc-99m or In-111) or −41% (I-125). The inclusion of scatter effects changed the above numbers to −12% (Tc-99m or In-111) and −21% (I-125), respectively, indicating the significance of scatter in quantitative I-125 imaging. Region-of-interest (ROI) definitions have greater impacts on regional quantitation accuracy for small sphere sources as compared to attenuation and scatter effects. For the same ROI, SPECT acquisitions using pinhole apertures of different sizes could significantly affect the outcome, whereas the use of different radii-of-rotation yielded negligible differences in quantitation accuracy for the imaging configurations simulated. Conclusions We have systematically quantified the influence of several factors affecting the quantitation accuracy of small animal pinhole SPECT. In order to consistently achieve accurate quantitation within 5% of the truth, comprehensive image compensation methods are needed. PMID:19048346

New Radiotracers for Imaging of Vascular Targets in Angiogenesis-related Diseases

PubMed Central

Hong, Hao; Chen, Feng; Zhang, Yin; Cai, Weibo

2014-01-01

Tremendous advances over the last several decades in positron emission tomography (PET) and single photon emission computed tomography (SPECT) allow for targeted imaging of molecular and cellular events in the living systems. Angiogenesis, a multistep process regulated by the network of different angiogenic factors, has attracted world-wide interests, due to its pivotal role in the formation and progression of different diseases including cancer, cardiovascular diseases (CVD), and inflammation. In this review article, we will summarize the recent progress in PET or SPECT imaging of a wide variety of vascular targets in three major angiogenesis-related diseases: cancer, cardiovascular diseases, and inflammation. Faster drug development and patient stratification for a specific therapy will become possible with the facilitation of PET or SPECT imaging and it will be critical for the maximum benefit of patients. PMID:25086372

Subacute cardiac rubidium-82 positron emission tomography (82Rb-PET) to assess myocardial area at risk, final infarct size, and myocardial salvage after STEMI.

PubMed

Ghotbi, Adam Ali; Kjaer, Andreas; Nepper-Christensen, Lars; Ahtarovski, Kiril Aleksov; Lønborg, Jacob Thomsen; Vejlstrup, Niels; Kyhl, Kasper; Christensen, Thomas Emil; Engstrøm, Thomas; Kelbæk, Henning; Holmvang, Lene; Bang, Lia E; Ripa, Rasmus Sejersten; Hasbak, Philip

2018-06-01

Determining infarct size and myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI) is important when assessing the efficacy of new reperfusion strategies. We investigated whether rest 82 Rb-PET myocardial perfusion imaging can estimate area at risk, final infarct size, and myocardial salvage index when compared to cardiac SPECT and magnetic resonance (CMR). Twelve STEMI patients were injected with 99m Tc-Sestamibi intravenously immediate prior to reperfusion. SPECT, 82 Rb-PET, and CMR imaging were performed post-reperfusion and at a 3-month follow-up. An automated algorithm determined area at risk, final infarct size, and hence myocardial salvage index. SPECT, CMR, and PET were performed 2.2 ± 0.5, 34 ± 8.5, and 32 ± 24.4 h after reperfusion, respectively. Mean (± SD) area at risk were 35.2 ± 16.6%, 34.7 ± 11.3%, and 28.1 ± 16.1% of the left ventricle (LV) in SPECT, CMR, and PET, respectively, P = 0.04 for difference. Mean final infarct size estimates were 12.3 ± 15.4%, 13.7 ± 10.4%, and 11.9 ± 14.6% of the LV in SPECT, CMR, and PET imaging, respectively, P = .72. Myocardial salvage indices were 0.64 ± 0.33 (SPECT), 0.65 ± 0.20 (CMR), and 0.63 ± 0.28 (PET), (P = .78). 82 Rb-PET underestimates area at risk in patients with STEMI when compared to SPECT and CMR. However, our findings suggest that PET imaging seems feasible when assessing the clinical important parameters of final infarct size and myocardial salvage index, although with great variability, in a selected STEMI population with large infarcts. These findings should be confirmed in a larger population.

Quantitative PET and SPECT performance characteristics of the Albira Trimodal pre-clinical tomograph

NASA Astrophysics Data System (ADS)

Spinks, T. J.; Karia, D.; Leach, M. O.; Flux, G.

2014-02-01

The Albira Trimodal pre-clinical scanner comprises PET, SPECT and CT sub-systems and thus provides a range of pre-clinical imaging options. The PET component consists of three rings of single-crystal LYSO detectors with axial/transverse fields-of-view (FOVs) of 148/80 mm. The SPECT component has two opposing CsI detectors (100 × 100 mm2) with single-pinhole (SPH) or multi(9)-pinhole (MPH) collimators; the detectors rotate in 6° increments and their spacing can be adjusted to provide different FOVs (25 to 120 mm). The CT sub-system provides ‘low’ (200 µA, 35 kVp) or ‘high’ (400 µA, 45 kVp) power x-rays onto a flat-panel CsI detector. This study examines the performance characteristics and quantitative accuracy of the PET and SPECT components. Using the NEMA NU 4-2008 specifications (22Na point source), the PET spatial resolution is 1.5 + 0.1 mm on axis and sensitivity 6.3% (axial centre) and 4.6% (central 70 mm). The usable activity range is ≤ 10 MBq (18F) over which good linearity (within 5%) is obtained for a uniform cylinder spanning the axial FOV; increasing deviation from linearity with activity is, however, observed for the NEMA (mouse) line source phantom. Image uniformity axially is within 5%. Spatial resolution (SPH/MPH) for the minimum SPECT FOV used for mouse imaging (50 mm) is 1.5/1.7 mm and point source sensitivity 69/750 cps MBq-1. Axial uniformity of SPECT images (%CV of regions-of-interest counts along the axis) is mostly within 8% although there is a range of 30-40% for the largest FOV. The variation is significantly smaller within the central 40 mm. Instances of count rate nonlinearity (PET) and axial non-uniformity (SPECT) were found to be reproducible and thus amenable to empirical correction.

Diagnostic and prognostic value of additional SPECT/CT in sentinel lymph node mapping in breast cancer patients.

PubMed

Stanzel, Susanne; Pernthaler, Birgit; Schwarz, Thomas; Bjelic-Radisic, Vesna; Kerschbaumer, Stefan; Aigner, Reingard M

2018-06-01

of the study was to demonstrate the diagnostic and prognostic value of SPECT/CT in sentinel lymph node mapping (SLNM) in patients with invasive breast cancer. 114 patients with invasive breast cancer with clinically negative lymph nodes were included in this retrospective study as they were referred for SLNM with 99m Tc-nanocolloid. Planar image acquisition was accomplished in a one-day or two-day protocol depending on the schedule of the surgical procedure. Low dose SPECT/CT was performed after the planar images. The sentinel lymph node biopsy (SLNB) was considered false negative if a primary recurrence developed within 12 months after SLNB in the axilla from which a tumor-free SLN had been removed. Between December 2009 and December 2011, 114 patients (pts.) underwent SLNM with additional SPECT/CT. Planar imaging identified in 109 pts. 139 SLNs, which were tumor-positive in 42 nodes (n = 41 pts.). SPECT/CT identified in 81 pts. 151 additional SLNs, of which 19 were tumor-positive and led to therapy change (axillary lymph node dissection) in 11 pts. (9.6 %). Of overall 61 tumor-positive SLNs (n = 52 pts.) SPECT/CT detected all, whereas planar imaging detected only 42 of 61 ( P < 0.0001). No patient had lymph node metastasis within 12 months after SLNB in the axilla from which a tumor-free SLN had been removed resulting in a false-negative rate of 0 %. The local relapse rate was 1.8 % leading to a 4-year disease-free survival rate of 90 %. Among patients with breast cancer, the use of SPECT/CT-aided SLNM correlated due to a better anatomical localization and identification of planar not visible SLNs with a higher detection rate of SLNs. This led to therapeutic consequences and an excellent false-negative and 4-year disease-free survival rate. Schattauer GmbH.

Using the NEMA NU 4 PET image quality phantom in multipinhole small-animal SPECT.

PubMed

Harteveld, Anita A; Meeuwis, Antoi P W; Disselhorst, Jonathan A; Slump, Cornelis H; Oyen, Wim J G; Boerman, Otto C; Visser, Eric P

2011-10-01

Several commercial small-animal SPECT scanners using multipinhole collimation are presently available. However, generally accepted standards to characterize the performance of these scanners do not exist. Whereas for small-animal PET, the National Electrical Manufacturers Association (NEMA) NU 4 standards have been defined in 2008, such standards are still lacking for small-animal SPECT. In this study, the image quality parameters associated with the NEMA NU 4 image quality phantom were determined for a small-animal multipinhole SPECT scanner. Multiple whole-body scans of the NEMA NU 4 image quality phantom of 1-h duration were performed in a U-SPECT-II scanner using (99m)Tc with activities ranging between 8.4 and 78.2 MBq. The collimator contained 75 pinholes of 1.0-mm diameter and had a bore diameter of 98 mm. Image quality parameters were determined as a function of average phantom activity, number of iterations, postreconstruction spatial filter, and scatter correction. In addition, a mouse was injected with (99m)Tc-hydroxymethylene diphosphonate and was euthanized 6.5 h after injection. Multiple whole-body scans of this mouse of 1-h duration were acquired for activities ranging between 3.29 and 52.7 MBq. An increase in the number of iterations was accompanied by an increase in the recovery coefficients for the small rods (RC(rod)), an increase in the noise in the uniform phantom region, and a decrease in spillover ratios for the cold-air- and water-filled scatter compartments (SOR(air) and SOR(wat)). Application of spatial filtering reduced image noise but lowered RC(rod). Filtering did not influence SOR(air) and SOR(wat). Scatter correction reduced SOR(air) and SOR(wat). The effect of total phantom activity was primarily seen in a reduction of image noise with increasing activity. RC(rod), SOR(air), and SOR(wat) were more or less constant as a function of phantom activity. The relation between acquisition and reconstruction settings and image quality was confirmed in the (99m)Tc-hydroxymethylene diphosphonate mouse scans. Although developed for small-animal PET, the NEMA NU 4 image quality phantom was found to be useful for small-animal SPECT as well, allowing for objective determination of image quality parameters and showing the trade-offs between several of these parameters on variation of acquisition and reconstruction settings.

A case of Cotard syndrome: (123)I-IBZM SPECT imaging of striatal D(2) receptor binding.

PubMed

De Risio, Sergio; De Rossi, Giuseppe; Sarchiapone, Marco; Camardese, Giovanni; Carli, Vladimir; Cuomo, Chiara; Satta, Maria Antonietta; Di Giuda, Daniela

2004-01-15

A case of 'dèlire de nègation' that suddenly appeared in a 43-year-old male is presented. No alteration in regional cerebral blood, as measured by (99m)Tc-HMPAO-SPECT, was found, but (123)I-IBZM-SPECT analysis showed reduced striatal D(2) receptor binding that further decreased after treatment.

Technetium-99m-HMPAO SPECT in the evaluation of patients with a remote history of traumatic brain injury: a comparison with x-ray computed tomography.

PubMed

Gray, B G; Ichise, M; Chung, D G; Kirsh, J C; Franks, W

1992-01-01

The functional imaging modality has potential for demonstrating parenchymal abnormalities not detectable by traditional morphological imaging. Fifty-three patients with a remote history of traumatic brain injury (TBI) were studied with SPECT using 99mTc-hexamethylpropyleneamineoxime (HMPAO) and x-ray computed tomography (CT). Overall, 42 patients (80%) showed regional cerebral blood flow (rCBF) deficits by HMPAO SPECT, whereas 29 patients (55%) showed morphological abnormalities by CT. Out of 20 patients with minor head injury, 12 patients (60%) showed rCBF deficits and 5 patients (25%) showed CT abnormalities. Of 33 patients with major head injury, 30 patients (90%) showed rCBF deficits and 24 patients (72%) showed CT abnormalities. Thus, HMPAO SPECT was more sensitive than CT in detecting abnormalities in patients with a history of TBI, particularly in the minor head injury group. In the major head injury group, three patients showed localized cortical atrophy by CT and normal rCBF by HMPAO SPECT. In the evaluation of TBI patients, HMPAO SPECT is a useful technique to demonstrate regional brain dysfunction in the presence of morphological integrity as assessed by CT.

Additional value of hybrid SPECT/CT systems in neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas.

PubMed

Wong, K K; Chondrogiannis, S; Fuster, D; Ruiz, C; Marzola, M C; Giammarile, F; Colletti, P M; Rubello, D

The aim of this review was to evaluate the potential advantages of SPECT/CT hybrid imaging in the management of neuroendocrine tumors, adrenal tumors, pheochromocytomas and paragangliomas. From the collected data, the superiority of fused images was observed as providing both functional/molecular and morphological imaging compared to planar imaging. This provided an improvement in diagnostic imaging, with significant advantages as regards: (1) precise locating of the lesions; (2) an improvement in characterization of the findings, resulting higher specificity, improved sensitivity, and overall greater accuracy, (3) additional anatomical information derived from the CT component; (4) CT-based attenuation correction and potential for volumetric dosimetry calculations, and (5) improvement on the impact on patient management (e.g. in better defining treatment plans, in shortening surgical operating times). It can be concluded that SPECT/CT hybrid imaging provides the nuclear medicine physician with a powerful imaging modality in comparison to planar imaging, providing essential information about the location of lesions, and high quality homogeneous images. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

I-123 iomazenil single photon emission computed tomography for detecting loss of neuronal integrity in patients with traumatic brain injury.

PubMed

Abiko, Kagari; Ikoma, Katsunori; Shiga, Tohru; Katoh, Chietsugu; Hirata, Kenji; Kuge, Yuji; Kobayashi, Kentaro; Tamaki, Nagara

2017-12-01

Traumatic brain injury (TBI) causes brain dysfunction in many patients. Using C-11 flumazenil (FMZ) positron emission tomography (PET), we have detected and reported the loss of neuronal integrity, leading to brain dysfunction in TBI patients. Similarly to FMZ PET, I-123 iomazenil (IMZ) single photon emission computed tomography (SPECT) is widely used to determine the distribution of the benzodiazepine receptor (BZR) in the brain cortex. The purpose of this study is to examine whether IMZ SPECT is as useful as FMZ PET for evaluating the loss of neuronal integrity in TBI patients. The subjects of this study were seven patients who suffered from neurobehavioral disability. They underwent IMZ SPECT and FMZ PET. Nondisplaceable binding potential (BP ND ) was calculated from FMZ PET images. The uptake of IMZ was evaluated on the basis of lesion-to-pons ratio (LPR). The locations of low uptake levels were visually evaluated both in IMZ SPECT and FMZ PET images. We compared FMZ BP ND and (LPR-1) of IMZ SPECT. In the visual assessment, FMZ BP ND decreased in 11 regions. In IMZ SPECT, low uptake levels were observed in eight of the 11 regions. The rate of concordance between FMZ PET and IMZ SPECT was 72.7%. The mean values IMZ (LPR-1) (1.95 ± 1.01) was significantly lower than that of FMZ BP ND (2.95 ± 0.80 mL/mL). There was good correlation between FMZ BP ND and IMZ (LPR-1) (r = 0.80). IMZ SPECT findings were almost the same as FMZ PET findings in TBI patients. The results indicated that IMZ SPECT is useful for evaluating the loss of neuronal integrity. Because IMZ SPECT can be performed in various facilities, IMZ SPECT may become widely adopted for evaluating the loss of neuronal integrity.

A template-based approach to semi-quantitative SPECT myocardial perfusion imaging: Independent of normal databases.

PubMed

Hughes, Tyler; Shcherbinin, Sergey; Celler, Anna

2011-07-01

Normal patient databases (NPDs) are used to distinguish between normal and abnormal perfusion in SPECT myocardial perfusion imaging (MPI) and have gained wide acceptance in the clinical environment, yet there are limitations to this approach. This study introduces a template-based method for semi-quantitative MPI, which attempts to overcome some of the NPD limitations. Our approach involves the construction of a 3D digital healthy heart template from the delineation of the patient's left ventricle in the SPECT image. This patient-specific template of the heart, filled with uniform activity, is then analytically projected and reconstructed using the same algorithm as the original image. Subsequent to generating bulls-eye maps for the patient image (PB) and the template image (TB), a ratio (PB/TB) is calculated, which produces a reconstruction-artifact corrected image (CB). Finally, a threshold is used to define defects within CB enabling measurements of the perfusion defect extent (EXT). The SPECT-based template (Ts) measurements were compared to those of a CT-based "ideal" template (TI). Twenty digital phantoms were simulated: male and female, each with one healthy heart and nine hearts with various defects. Four physical phantom studies were performed modeling a healthy heart and three hearts with different defects. The phantom represented a thorax with spine, lung, and left ventricle inserts. Images were acquired on General Electric's (GE) Infinia Hawkeye SPECT/CT camera using standard clinical MPI protocol. Finally, our method was applied to 14 patient MPI rest/stress studies acquired on the GE Infinia Hawkeye SPECT/CT camera and compared to the results obtained from Cedars-Sinai's QPS software. In the simulation studies, the true EXT correlated well with the TI (slope= 1.08; offset = -0.40%; r = 0.99) and Ts (slope = 0.90; offset = 0.27%; r = 0.99) methods with no significant differences between them. Similarly, strong correlations were measured for EXT obtained from QPS and the template method for patient studies (slope =0.91; offset = 0.45%; r = 0.98). Mean errors in extent for the Ts method using simulation, physical phantom, and patient data were 2.7% +/- 2.4%, 0.9% +/- 0.5%, 2.0% +/- 2.7%, respectively. The authors introduced a method for semi-quantitative SPECT MPI, which offers a patient-specific approach to define the perfusion defect regions within the heart, as opposed to the patient-averaged NPD methodology.

Assessment of left ventricular mechanical dyssynchrony by phase analysis of gated-SPECT myocardial perfusion imaging and tissue Doppler imaging: comparison between QGS and ECTb software packages.

PubMed

Rastgou, Fereydoon; Shojaeifard, Maryam; Amin, Ahmad; Ghaedian, Tahereh; Firoozabadi, Hasan; Malek, Hadi; Yaghoobi, Nahid; Bitarafan-Rajabi, Ahmad; Haghjoo, Majid; Amouzadeh, Hedieh; Barati, Hossein

2014-12-01

Recently, the phase analysis of gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has become feasible via several software packages for the evaluation of left ventricular mechanical dyssynchrony. We compared two quantitative software packages, quantitative gated SPECT (QGS) and Emory cardiac toolbox (ECTb), with tissue Doppler imaging (TDI) as the conventional method for the evaluation of left ventricular mechanical dyssynchrony. Thirty-one patients with severe heart failure (ejection fraction ≤35%) and regular heart rhythm, who referred for gated-SPECT MPI, were enrolled. TDI was performed within 3 days after MPI. Dyssynchrony parameters derived from gated-SPECT MPI were analyzed by QGS and ECTb and were compared with the Yu index and septal-lateral wall delay measured by TDI. QGS and ECTb showed a good correlation for assessment of phase histogram bandwidth (PHB) and phase standard deviation (PSD) (r = 0.664 and r = 0.731, P < .001, respectively). However, the mean value of PHB and PSD by ECTb was significantly higher than that of QGS. No significant correlation was found between ECTb and QGS and the Yu index. Nevertheless, PHB, PSD, and entropy derived from QGS revealed a significant (r = 0.424, r = 0.478, r = 0.543, respectively; P < .02) correlation with septal-lateral wall delay. Despite a good correlation between QGS and ECTb software packages, different normal cut-off values of PSD and PHB should be defined for each software package. There was only a modest correlation between phase analysis of gated-SPECT MPI and TDI data, especially in the population of heart failure patients with both narrow and wide QRS complex.

Stroma Targeting Nuclear Imaging and Radiopharmaceuticals

PubMed Central

Shetty, Dinesh; Jeong, Jae-Min; Shim, Hyunsuk

2012-01-01

Malignant transformation of tumor accompanies profound changes in the normal neighboring tissue, called tumor stroma. The tumor stroma provides an environment favoring local tumor growth, invasion, and metastatic spreading. Nuclear imaging (PET/SPECT) measures biochemical and physiologic functions in the human body. In oncology, PET/SPECT is particularly useful for differentiating tumors from postsurgical changes or radiation necrosis, distinguishing benign from malignant lesions, identifying the optimal site for biopsy, staging cancers, and monitoring the response to therapy. Indeed, PET/SPECT is a powerful, proven diagnostic imaging modality that displays information unobtainable through other anatomical imaging, such as CT or MRI. When combined with coregistered CT data, [18F]fluorodeoxyglucose ([18F]FDG)-PET is particularly useful. However, [18F]FDG is not a target-specific PET tracer. This paper will review the tumor microenvironment targeting oncologic imaging such as angiogenesis, invasion, hypoxia, growth, and homing, and also therapeutic radiopharmaceuticals to provide a roadmap for additional applications of tumor imaging and therapy. PMID:22685650

Imaging characterization of a new gamma ray detector based on CRY019 scintillation crystal for PET and SPECT applications

NASA Astrophysics Data System (ADS)

Polito, C.; Pani, R.; Trigila, C.; Cinti, M. N.; Fabbri, A.; Frantellizzi, V.; De Vincentis, G.; Pellegrini, R.; Pani, R.

2017-02-01

In the last 40 years, in the field of Molecular Medicine imaging there has been a huge growth in the employment and in the improvement of detectors for PET and SPECT applications in order to reach accurate diagnosis of the diseases. The most important feature required to these detectors is an high quality of images that is usually obtained benefitting from the development of a wide number of new scintillation crystals with high imaging performances. In this contest, features like high detection efficiency, short decay time, great spectral match with photodetectors, absence of afterglow and low costs are surely attractive. However, there are other factors playing an important role in the realization of high quality images such as energy and spatial resolutions, position linearity and contrast resolution. With the aim to realize an high performace gamma ray detector for PET and SPECT applications, this work is focused on the evaluation of the imaging characteristics of a recently developed scintillation crystal, CRY019.

Use Of Clinical Decision Analysis In Predicting The Efficacy Of Newer Radiological Imaging Modalities: Radioscintigraphy Versus Single Photon Transverse Section Emission Computed Tomography

NASA Astrophysics Data System (ADS)

Prince, John R.

1982-12-01

Sensitivity, specificity, and predictive accuracy have been shown to be useful measures of the clinical efficacy of diagnostic tests and can be used to predict the potential improvement in diagnostic certitude resulting from the introduction of a competing technology. This communication demonstrates how the informal use of clinical decision analysis may guide health planners in the allocation of resources, purchasing decisions, and implementation of high technology. For didactic purposes the focus is on a comparison between conventional planar radioscintigraphy (RS) and single photon transverse section emission conputed tomography (SPECT). For example, positive predictive accuracy (PPA) for brain RS in a specialist hospital with a 50% disease prevalance is about 95%. SPECT should increase this predicted accuracy to 96%. In a primary care hospital with only a 15% disease prevalance the PPA is only 77% and SPECT may increase this accuracy to about 79%. Similar calculations based on published data show that marginal improvements are expected with SPECT in the liver. It is concluded that: a) The decision to purchase a high technology imaging modality such as SPECT for clinical purposes should be analyzed on an individual organ system and institutional basis. High technology may be justified in specialist hospitals but not necessarily in primary care hospitals. This is more dependent on disease prevalance than procedure volume; b) It is questionable whether SPECT imaging will be competitive with standard RS procedures. Research should concentrate on the development of different medical applications.

A single CT for attenuation correction of both rest and stress SPECT myocardial perfusion imaging: a retrospective feasibility study

PubMed Central

Ahlman, Mark A; Nietert, Paul J; Wahlquist, Amy E; Serguson, Jill M; Berry, Max W; Suranyi, Pal; Liu, Songtao; Spicer, Kenneth M

2014-01-01

Purpose: In the effort to reduce radiation exposure to patients undergoing myocardial perfusion imaging (MPI) with SPECT/CT, we evaluate the feasibility of a single CT for attenuation correction (AC) of single-day rest (R)/stress (S) perfusion. Methods: Processing of 20 single isotope and 20 dual isotope MPI with perfusion defects were retrospectively repeated in three steps: (1) the standard method using a concurrent R-CT for AC of R-SPECT and S-CT for S-SPECT; (2) the standard method repeated; and (3) with the R-CT used for AC of S-SPECT, and the S-CT used for AC of R-SPECT. Intra-Class Correlation Coefficients (ICC) and Choen’s kappa were used to measure intra-operator variability in sum scoring. Results: The highest level of intra-operator reliability was seen with the reproduction of the sum rest score (SRS) and sum stress score (SSS) (ICC > 95%). ICCs were > 85% for SRS and SSS when alternate CTs were used for AC, but when sum difference scores were calculated, ICC values were much lower (~22% to 27%), which may imply that neither CT substitution resulted in a reproducible difference score. Similar results were seen when evaluating dichotomous outcomes (sum scores difference of ≥ 4) when comparing different processing techniques (kappas ~0.32 to 0.43). Conclusions: When a single CT is used for AC of both rest and stress SPECT, there is disproportionately high variability in sum scoring that is independent of user error. This information can be used to direct further investigation in radiation reduction for common imaging exams in nuclear medicine. PMID:24482701

Quantifying regional cerebral blood flow by N-isopropyl-P-[I-123]iodoamphetamine (IMP) using a ring type single-photon emission computed tomography system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, N.; Odano, I.; Ohkubo, M.

1994-05-01

We developed a more accurate quantitative measurement of regional cerebral blood flow (rCBF) with the microsphere model using N-isopropyl-p-[I-123] iodoamphetamine (IMP) and a ring type single photon emission computed tomography (SPECT) system. SPECT studies were performed in 17 patients with brain diseases. A dose of 222 MBq (6 mCi) of [I-123]IMP was injected i.v., at the same time a 5 min period of arterial blood withdrawal was begun. SPECT data were acquired from 25 min to 60 min after tracer injection. For obtaining the brain activity concentration at 5 min after IMP injection, total brain counts collections and one minutemore » period short time SPECT studies were performed at 5, 20, and 60 min. Measurement of the values of rCBF was calculated using short time SPECT images at 5 min (rCBF), static SPECT images corrected with total cerebral counts (rCBF{sub Ct}.) and those corrected with reconstructed counts on short time SPECT images (rCBF{sub Cb}). There was a good relationship (r=0.69) between rCBF and rCBF{sub Ct}, however, rCBF{sub Ct} tends to be underestimated in high flow areas and overestimated in low flow areas. There was better relationship between rCBF and rCBF{sub Cb}(r=0.92). The overestimation and underestimation shown in rCBF{sub Ct} was considered to be due to the correction of reconstructed counts using a total cerebral time activity curve, because of the kinetic behavior of [I-123]IMP was different in each region. We concluded that more accurate rCBF values could be obtained using the regional time activity curves.« less

An evaluation to design high performance pinhole array detector module for four head SPECT: a simulation study

NASA Astrophysics Data System (ADS)

Rahman, Tasneem; Tahtali, Murat; Pickering, Mark R.

2014-09-01

The purpose of this study is to derive optimized parameters for a detector module employing an off-the-shelf X-ray camera and a pinhole array collimator applicable for a range of different SPECT systems. Monte Carlo simulations using the Geant4 application for tomographic emission (GATE) were performed to estimate the performance of the pinhole array collimators and were compared to that of low energy high resolution (LEHR) parallel-hole collimator in a four head SPECT system. A detector module was simulated to have 48 mm by 48 mm active area along with 1mm, 1.6mm and 2 mm pinhole aperture sizes at 0.48 mm pitch on a tungsten plate. Perpendicular lead septa were employed to verify overlapping and non-overlapping projections against a proper acceptance angle without lead septa. A uniform shape cylindrical water phantom was used to evaluate the performance of the proposed four head SPECT system of the pinhole array detector module. For each head, 100 pinhole configurations were evaluated based on sensitivity and detection efficiency for 140 keV γ-rays, and compared to LEHR parallel-hole collimator. SPECT images were reconstructed based on filtered back projection (FBP) algorithm where neither scatter nor attenuation corrections were performed. A better reconstruction algorithm development for this specific system is in progress. Nevertheless, activity distribution was well visualized using the backprojection algorithm. In this study, we have evaluated several quantitative and comparative analyses for a pinhole array imaging system providing high detection efficiency and better system sensitivity over a large FOV, comparing to the conventional four head SPECT system. The proposed detector module is expected to provide improved performance in various SPECT imaging.

Ejection fraction in myocardial perfusion imaging assessed with a dynamic phantom: comparison between IQ-SPECT and LEHR.

PubMed

Hippeläinen, Eero; Mäkelä, Teemu; Kaasalainen, Touko; Kaleva, Erna

2017-12-01

Developments in single photon emission tomography instrumentation and reconstruction methods present a potential for decreasing acquisition times. One of such recent options for myocardial perfusion imaging (MPI) is IQ-SPECT. This study was motivated by the inconsistency in the reported ejection fraction (EF) and left ventricular (LV) volume results between IQ-SPECT and more conventional low-energy high-resolution (LEHR) collimation protocols. IQ-SPECT and LEHR quantitative results were compared while the equivalent number of iterations (EI) was varied. The end-diastolic (EDV) and end-systolic volumes (ESV) and the derived EF values were investigated. A dynamic heart phantom was used to produce repeatable ESVs, EDVs and EFs. Phantom performance was verified by comparing the set EF values to those measured from a gated multi-slice X-ray computed tomography (CT) scan (EF True ). The phantom with an EF setting of 45, 55, 65 and 70% was imaged with both IQ-SPECT and LEHR protocols. The data were reconstructed with different EI, and two commonly used clinical myocardium delineation software were used to evaluate the LV volumes. The CT verification showed that the phantom EF settings were repeatable and accurate with the EF True being within 1% point from the manufacture's nominal value. Depending on EI both MPI protocols can be made to produce correct EF estimates, but IQ-SPECT protocol produced on average 41 and 42% smaller EDV and ESV when compared to the phantom's volumes, while LEHR protocol underestimated volumes by 24 and 21%, respectively. The volume results were largely similar between the delineation methods used. The reconstruction parameters can greatly affect the volume estimates obtained from perfusion studies. IQ-SPECT produces systematically smaller LV volumes than the conventional LEHR MPI protocol. The volume estimates are also software dependent.

Avoiding full corrections in dynamic SPECT images impacts the performance of SPECT myocardial blood flow quantitation.

PubMed

Wang, Lei; Wu, Dayong; Yang, Yong; Chen, Ing-Jou; Lin, Chih-Yuan; Hsu, Bailing; Fang, Wei; Tang, Yi-Da

2017-08-01

This study investigated the performance of SPECT myocardial blood flow (MBF) quantitation lacking full physical corrections (All Corr) in dynamic SPECT (DySPECT) images. Eleven healthy normal volunteers (HVT) and twenty-four patients with angiography-documented CAD were assessed. All Corr in 99m Tc-sestamibi DySPECT encompassed noise reduction (NR), resolution recovery (RR), and corrections for scatter (SC) and attenuation (AC), otherwise no correction (NC) or only partial corrections. The performance was evaluated by quality index (R 2 ) and blood-pool spillover index (FBV) in kinetic modeling, and by rest flow (RMBF) and stress flow (SMBF) compared with those of All Corr. In HVT group, NC diminished 2-fold flow uniformity with the most degraded quality (15%-18% reduced R 2 ) and elevated spillover effect (45%-50% increased FBV). Consistently higher RMBF and SMBF were discovered in both groups (HVT 1.54/2.31 higher; CAD 1.60/1.72; all P < .0001). Bland-Altman analysis revealed positive flow bias (HVT 0.9-2.6 mL/min/g; CAD 0.7-1.3) with wide ranges of 95% CI of agreement (HVT NC -1.9-7.1; NR -0.4-4.4; NR + SC -1.1-4.3; NR + SC + RR -0.7-2.5) (CAD NC -1.2-3.8; NR -1.0-2.8; NR + SC -1.0-2.5; NR + SC + RR -1.1-2.6). Uncorrected physical interference in DySPECT images can extensively impact the performance of MBF quantitation. Full physical corrections should be considered to warrant this tool for clinical utilization.

Rapid Synthesis of 68Ga-labeled macroaggregated human serum albumin (MAA) for routine application in perfusion imaging using PET/CT.

PubMed

Mueller, D; Kulkarni, Harshad; Baum, Richard P; Odparlik, Andreas

2017-04-01

99m Tc-labeled MAA is commonly used for single photon emission computed tomography SPECT. In contrast, positron emission tomography/CT (PET/CT) delivers images with significantly higher resolution. The generator produced radionuclide 68 Ga is widely used for PET/CT imaging agents and 68 Ga-labeled MAA represents an attractive alternative to 99m Tc-labeled MAA. We report a simple and rapid NaCl based labeling procedure for the labeling of MAA with 68 Ga using a commercially available MAA labeling kit for 99m Tc. The procedure delivers 68 Ga-labeled MAA with a high specific activity and a high labeling efficiency (>99%). The synthesis does not require a final step of separation or the use of organic solvents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Automatic estimation of detector radial position for contoured SPECT acquisition using CT images on a SPECT/CT system.

PubMed

Liu, Ruijie Rachel; Erwin, William D

2006-08-01

An algorithm was developed to estimate noncircular orbit (NCO) single-photon emission computed tomography (SPECT) detector radius on a SPECT/CT imaging system using the CT images, for incorporation into collimator resolution modeling for iterative SPECT reconstruction. Simulated male abdominal (arms up), male head and neck (arms down) and female chest (arms down) anthropomorphic phantom, and ten patient, medium-energy SPECT/CT scans were acquired on a hybrid imaging system. The algorithm simulated inward SPECT detector radial motion and object contour detection at each projection angle, employing the calculated average CT image and a fixed Hounsfield unit (HU) threshold. Calculated radii were compared to the observed true radii, and optimal CT threshold values, corresponding to patient bed and clothing surfaces, were found to be between -970 and -950 HU. The algorithm was constrained by the 45 cm CT field-of-view (FOV), which limited the detected radii to < or = 22.5 cm and led to occasional radius underestimation in the case of object truncation by CT. Two methods incorporating the algorithm were implemented: physical model (PM) and best fit (BF). The PM method computed an offset that produced maximum overlap of calculated and true radii for the phantom scans, and applied that offset as a calculated-to-true radius transformation. For the BF method, the calculated-to-true radius transformation was based upon a linear regression between calculated and true radii. For the PM method, a fixed offset of +2.75 cm provided maximum calculated-to-true radius overlap for the phantom study, which accounted for the camera system's object contour detect sensor surface-to-detector face distance. For the BF method, a linear regression of true versus calculated radius from a reference patient scan was used as a calculated-to-true radius transform. Both methods were applied to ten patient scans. For -970 and -950 HU thresholds, the combined overall average root-mean-square (rms) error in radial position for eight patient scans without truncation were 3.37 cm (12.9%) for PM and 1.99 cm (8.6%) for BF, indicating BF is superior to PM in the absence of truncation. For two patient scans with truncation, the rms error was 3.24 cm (12.2%) for PM and 4.10 cm (18.2%) for BF. The slightly better performance of PM in the case of truncation is anomalous, due to FOV edge truncation artifacts in the CT reconstruction, and thus is suspect. The calculated NCO contour for a patient SPECT/CT scan was used with an iterative reconstruction algorithm that incorporated compensation for system resolution. The resulting image was qualitatively superior to the image obtained by reconstructing the data using the fixed radius stored by the scanner. The result was also superior to the image reconstructed using the iterative algorithm provided with the system, which does not incorporate resolution modeling. These results suggest that, under conditions of no or only mild lateral truncation of the CT scan, the algorithm is capable of providing radius estimates suitable for iterative SPECT reconstruction collimator geometric resolution modeling.

In vivo features of melanocytic lesions: multimode hyperspectral dermoscopy, reflectance confocal microscopy, and histopathologic correlates (Conference Presentation)

NASA Astrophysics Data System (ADS)

Vasefi, Fartash; MacKinnon, Nicholas B.; Jain, Manu; Cordova, Miguel A.; Kose, Kivanc; Rajadhyaksha, Milind; Halpern, Allan C.; Farkas, Daniel L.

2017-02-01

Motivation and background: Melanoma, the fastest growing cancer worldwide, kills more than one person every hour in the United States. Determining the depth and distribution of dermal melanin and hemoglobin adds physio-morphologic information to the current diagnostic standard, cellular morphology, to further develop noninvasive methods to discriminate between melanoma and benign skin conditions. Purpose: To compare the performance of a multimode dermoscopy system (SkinSpect), which is designed to quantify and map in three dimensions, in vivo melanin and hemoglobin in skin, and to validate this with histopathology and three dimensional reflectance confocal microscopy (RCM) imaging. Methods: Sequentially capture SkinSpect and RCM images of suspect lesions and nearby normal skin and compare this with histopathology reports, RCM imaging allows noninvasive observation of nuclear, cellular and structural detail in 1-5 μm-thin optical sections in skin, and detection of pigmented skin lesions with sensitivity of 90-95% and specificity of 70-80%. The multimode imaging dermoscope combines polarization (cross and parallel), autofluorescence and hyperspectral imaging to noninvasively map the distribution of melanin, collagen and hemoglobin oxygenation in pigmented skin lesions. Results: We compared in vivo features of ten melanocytic lesions extracted by SkinSpect and RCM imaging, and correlated them to histopathologic results. We present results of two melanoma cases (in situ and invasive), and compare with in vivo features from eight benign lesions. Melanin distribution at different depths and hemodynamics, including abnormal vascularity, detected by both SkinSpect and RCM will be discussed. Conclusion: Diagnostic features such as dermal melanin and hemoglobin concentration provided in SkinSpect skin analysis for melanoma and normal pigmented lesions can be compared and validated using results from RCM and histopathology.

Clinical utility of indigenously formulated single-vial lyophilized HYNIC-TOC kit in evaluating Gastro-entero Pancreatic neuro endocrine tumours

PubMed Central

Shinto, Ajit S; Kamaleshwaran, K; Vyshak, K; Sudhakar, Natarajan; Banerjee, Sharmila; Korde, Aruna; Samuel, Grace; Mallia, Madhav

2014-01-01

Objective(s): The objective of this study was to evaluate the performance and utility of 99mTc HYNIC-TOC planar scintigraphy and SPECT/CT in the diagnosis, staging and management of gastroenteropancreatic neuroendocrine tumors (GPNETs). Methods: 22 patients (median age, 46 years) with histologically proven gastro- entero- pancreatic NETs underwent 99mTc HYNIC-TOC whole body scintigraphy and regional SPECT/CT as indicated. Scanning was performed after injection of 370-550 MBq (10-15 mCi) of 99mTc HYNIC-TOC intravenously. Images were evaluated by two experienced nuclear medicine physicians both qualitatively as well as semi quantitatively (tumor to background and tumor to normal liver ratios on SPECT -CT images). Results of SPECT/CT were compared with the results of conventional imaging. Histopathology results and follow-up somatostatin receptor scintigraphy with 99mTc HYNIC TOC or conventional imaging with biochemical markers were considered to be the reference standards. Results: 99mTc HYNIC TOC showed sensitivity and specificity of 87.5% and 85.7%, respectively, for primary tumor and 100% and 86% for metastases. It was better than conventional imaging modalities for the detection of both primary tumor (P<0.001) and metastases (P<0.0001). It changed the management strategy in 6 patients (31.8%) and supported management decisions in 8 patients (36.3%). Conclusion: 99mTc HYNIC TOC SPECT/CT appears to be a highly sensitive and specific modality for the detection and staging of GPNETs. It is better than conventional imaging for the evaluation of GPNETs and can have a significant impact on patient management and planning further therapeutic options. PMID:27408857

Clinical utility of indigenously formulated single-vial lyophilized HYNIC-TOC kit in evaluating Gastro-entero Pancreatic neuro endocrine tumours.

PubMed

Shinto, Ajit S; Kamaleshwaran, K; Vyshak, K; Sudhakar, Natarajan; Banerjee, Sharmila; Korde, Aruna; Samuel, Grace; Mallia, Madhav

2014-01-01

The objective of this study was to evaluate the performance and utility of (99m)Tc HYNIC-TOC planar scintigraphy and SPECT/CT in the diagnosis, staging and management of gastroenteropancreatic neuroendocrine tumors (GPNETs). 22 patients (median age, 46 years) with histologically proven gastro- entero- pancreatic NETs underwent (99m)Tc HYNIC-TOC whole body scintigraphy and regional SPECT/CT as indicated. Scanning was performed after injection of 370-550 MBq (10-15 mCi) of (99m)Tc HYNIC-TOC intravenously. Images were evaluated by two experienced nuclear medicine physicians both qualitatively as well as semi quantitatively (tumor to background and tumor to normal liver ratios on SPECT -CT images). Results of SPECT/CT were compared with the results of conventional imaging. Histopathology results and follow-up somatostatin receptor scintigraphy with (99m)Tc HYNIC TOC or conventional imaging with biochemical markers were considered to be the reference standards. (99m)Tc HYNIC TOC showed sensitivity and specificity of 87.5% and 85.7%, respectively, for primary tumor and 100% and 86% for metastases. It was better than conventional imaging modalities for the detection of both primary tumor (P<0.001) and metastases (P<0.0001). It changed the management strategy in 6 patients (31.8%) and supported management decisions in 8 patients (36.3%). (99m)Tc HYNIC TOC SPECT/CT appears to be a highly sensitive and specific modality for the detection and staging of GPNETs. It is better than conventional imaging for the evaluation of GPNETs and can have a significant impact on patient management and planning further therapeutic options.

Task Equivalence for Model and Human-Observer Comparisons in SPECT Localization Studies

NASA Astrophysics Data System (ADS)

Sen, Anando; Kalantari, Faraz; Gifford, Howard C.

2016-06-01

While mathematical model observers are intended for efficient assessment of medical imaging systems, their findings should be relevant for human observers as the primary clinical end users. We have investigated whether pursuing equivalence between the model and human-observer tasks can help ensure this goal. A localization receiver operating characteristic (LROC) study tested prostate lesion detection in simulated In-111 SPECT imaging with anthropomorphic phantoms. The test images were 2D slices extracted from reconstructed volumes. The iterative ordered sets expectation-maximization (OSEM) reconstruction algorithm was used with Gaussian postsmoothing. Variations in the number of iterations and the level of postfiltering defined the test strategies in the study. Human-observer performance was compared with that of a visual-search (VS) observer, a scanning channelized Hotelling observer, and a scanning channelized nonprewhitening (CNPW) observer. These model observers were applied with precise information about the target regions of interest (ROIs). ROI knowledge was a study variable for the human observers. In one study format, the humans read the SPECT image alone. With a dual-modality format, the SPECT image was presented alongside an anatomical image slice extracted from the density map of the phantom. Performance was scored by area under the LROC curve. The human observers performed significantly better with the dual-modality format, and correlation with the model observers was also improved. Given the human-observer data from the SPECT study format, the Pearson correlation coefficients for the model observers were 0.58 (VS), -0.12 (CH), and -0.23 (CNPW). The respective coefficients based on the human-observer data from the dual-modality study were 0.72, 0.27, and -0.11. These results point towards the continued development of the VS observer for enhancing task equivalence in model-observer studies.

Correlation of myocardial p-(123)I-iodophenylpentadecanoic acid retention with (18)F-FDG accumulation during experimental low-flow ischemia.

PubMed

Shi, Cindy Q; Young, Lawrence H; Daher, Edouard; DiBella, Edward V R; Liu, Yi-Hwa; Heller, Eliot N; Zoghbi, Sami; Wackers, Frans J Th; Soufer, Robert; Sinusas, Albert J

2002-03-01

Myocardial ischemia is associated with reduced free fatty acid (FFA) beta-oxidation and increased glucose utilization. This study evaluated the potential of dynamic SPECT imaging of a FFA analog, p-(123)I-iodophenylpentadecanoic acid (IPPA), for detection of ischemia and compares retention of IPPA with (18)F-FDG accumulation. In a canine model of regional low-flow ischemia (n = 9), serial IPPA SPECT images (2 min per image) were acquired over 52--90 min. In a subset of dogs (n = 6), (18)F-FDG was injected after completing SPECT imaging and allowed to accumulate for 40 min before killing the animals. Flow was assessed with radiolabeled microspheres. Myocardial metabolism was evaluated independently by selective coronary arterial and venous sampling. Serial IPPA SPECT images showed an initial defect in the ischemic region (0.70% plus minus 0.03% ischemic-to-nonischemic ratio), which normalized within 48 min because of the slower IPPA clearance from the ischemic region (t(1/2) = 54.2 plus minus 3.3 min) relative to the nonischemic region (t(1/2) = 36.7 plus minus 5.6 min) (P < 0.05). Delayed myocardial IPPA and (18)F-FDG activities were correlated (r = 0.70; n = 576 segments), and both were maximally increased in segments with a moderate flow reduction (IPPA, 151% of nonischemic; (18)F-FDG, 450% of nonischemic; P < 0.05). Serial SPECT imaging showed delayed myocardial clearance of IPPA in ischemic regions with moderate flow reduction, which lead to increased late myocardial retention of IPPA. Retention of IPPA correlated with (18)F-FDG accumulation, supporting the potential of IPPA as a noninvasive marker of ischemic myocardium.

SU-E-I-81: Targeting of HER2-Expressing Tumors with Dual PET-MR Imaging Probes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, P; Peng, Y; Sun, M

2015-06-15

Purpose: The detection of human epidermal growth factor receptor type 2 (HER2) expression in malignant tumors provides important information influencing patient management. Radionuclide in vivo imaging of HER2 may permit the detection of HER2 in both primary tumors and metastases by a single noninvasive procedure. Trastuzumab, effective in about 15 % of women with breast cancer, downregulates signalling through the Akt/PI3K and MAPK pathways.These pathways modulate metabolism which can be monitored by positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: The relationship between response of HER2 overexpressing tumours and changes in imaging PET or SPECT and MRI willmore » be examined by a integrated bimodal imaging probe.Small (7 kDa) high-affinity anti-HER2 Affibody molecules and KCCYSL targeting peptide may be suitable tracers for visualization of HER2-expressing tumors. Peptide-conjugated iron oxide nanoparticles (Fe3O4 NPs) as MRI imaging and CB-TE2A as PET imaging are integrated into a single synthetic molecule in the HER2 positive cancer. Results: One of targeted contrast bimodal imaging probe agents was synthesized and evaluated to target HER2-expressing tumors in a HER2 positive rat model. We will report the newest results regarding the development of bimodal imaging probes. Conclusion: The preliminary results of the bimodal imaging probe presents high correlation of MRI signal and PET imaging intensity in vivo. This unique feature can hardly be obtained by single model contrast agents. It is envisioned that this bimodal agents can hold great potential for accurate detection of HER2-expressing tumors which are critical for clinical management of the disease.« less

Recovered neuronal viability revealed by Iodine-123-iomazenil SPECT following traumatic brain injury.

PubMed

Koizumi, Hiroyasu; Fujisawa, Hirosuke; Kurokawa, Tetsu; Suehiro, Eiichi; Iwanaga, Hideyuki; Nakagawara, Jyoji; Suzuki, Michiyasu

2010-10-01

We evaluated cortical damages following traumatic brain injury (TBI) in the acute phase with [(123)I] iomazenil (IMZ) single photon emission computed tomography (SPECT). In all, 12 patients with cerebral contusion following TBI were recruited. All patients underwent IMZ SPECT within 1 week after TBI. To investigate the changes in distribution of IMZ in the cortex in the chronic phase, after conventional treatment, patients underwent IMZ SPECT again. A decrease in the accumulation of radioligand for the central benzodiazepine receptor in the cortex corresponding to the contusion revealed with computed tomography (CT) scans and magnetic resonance imaging (MRI) were shown on IMZ SPECT in the acute phase in all patients. In 9 of 12 patients (75%), images of IMZ SPECT obtained in the chronic phase of TBI showed that areas with a decreased distribution of IMZ were remarkably reduced in comparison with those obtained in the acute phase. Both CT scans and MRI showed a normal appearance of the cortex morphologically, where the binding potential of IMZ recovered in the chronic phase. Reduced binding potential of radioligand for the central benzodiazepine receptor is considered to be an irreversible reaction; however, in this study, IMZ accumulation in the cortex following TBI was recovered in the chronic phase in several patients. [(123)I] iomazenil SPECT may have a potential to disclose a reversible vulnerability of neurons following TBI.

Recovered neuronal viability revealed by Iodine-123-iomazenil SPECT following traumatic brain injury

PubMed Central

Koizumi, Hiroyasu; Fujisawa, Hirosuke; Kurokawa, Tetsu; Suehiro, Eiichi; Iwanaga, Hideyuki; Nakagawara, Jyoji; Suzuki, Michiyasu

2010-01-01

We evaluated cortical damages following traumatic brain injury (TBI) in the acute phase with [123I] iomazenil (IMZ) single photon emission computed tomography (SPECT). In all, 12 patients with cerebral contusion following TBI were recruited. All patients underwent IMZ SPECT within 1 week after TBI. To investigate the changes in distribution of IMZ in the cortex in the chronic phase, after conventional treatment, patients underwent IMZ SPECT again. A decrease in the accumulation of radioligand for the central benzodiazepine receptor in the cortex corresponding to the contusion revealed with computed tomography (CT) scans and magnetic resonance imaging (MRI) were shown on IMZ SPECT in the acute phase in all patients. In 9 of 12 patients (75%), images of IMZ SPECT obtained in the chronic phase of TBI showed that areas with a decreased distribution of IMZ were remarkably reduced in comparison with those obtained in the acute phase. Both CT scans and MRI showed a normal appearance of the cortex morphologically, where the binding potential of IMZ recovered in the chronic phase. Reduced binding potential of radioligand for the central benzodiazepine receptor is considered to be an irreversible reaction; however, in this study, IMZ accumulation in the cortex following TBI was recovered in the chronic phase in several patients. [123I] iomazenil SPECT may have a potential to disclose a reversible vulnerability of neurons following TBI. PMID:20683454

Value of automatic patient motion detection and correction in myocardial perfusion imaging using a CZT-based SPECT camera.

PubMed

van Dijk, Joris D; van Dalen, Jorn A; Mouden, Mohamed; Ottervanger, Jan Paul; Knollema, Siert; Slump, Cornelis H; Jager, Pieter L

2018-04-01

Correction of motion has become feasible on cadmium-zinc-telluride (CZT)-based SPECT cameras during myocardial perfusion imaging (MPI). Our aim was to quantify the motion and to determine the value of automatic correction using commercially available software. We retrospectively included 83 consecutive patients who underwent stress-rest MPI CZT-SPECT and invasive fractional flow reserve (FFR) measurement. Eight-minute stress acquisitions were reformatted into 1.0- and 20-second bins to detect respiratory motion (RM) and patient motion (PM), respectively. RM and PM were quantified and scans were automatically corrected. Total perfusion deficit (TPD) and SPECT interpretation-normal, equivocal, or abnormal-were compared between the noncorrected and corrected scans. Scans with a changed SPECT interpretation were compared with FFR, the reference standard. Average RM was 2.5 ± 0.4 mm and maximal PM was 4.5 ± 1.3 mm. RM correction influenced the diagnostic outcomes in two patients based on TPD changes ≥7% and in nine patients based on changed visual interpretation. In only four of these patients, the changed SPECT interpretation corresponded with FFR measurements. Correction for PM did not influence the diagnostic outcomes. Respiratory motion and patient motion were small. Motion correction did not appear to improve the diagnostic outcome and, hence, the added value seems limited in MPI using CZT-based SPECT cameras.

(⁹⁹m)Tc-MAA overestimates the absorbed dose to the lungs in radioembolization: a quantitative evaluation in patients treated with ¹⁶⁶Ho-microspheres.

PubMed

Elschot, Mattijs; Nijsen, Johannes F W; Lam, Marnix G E H; Smits, Maarten L J; Prince, Jip F; Viergever, Max A; van den Bosch, Maurice A A J; Zonnenberg, Bernard A; de Jong, Hugo W A M

2014-10-01

Radiation pneumonitis is a rare but serious complication of radioembolic therapy of liver tumours. Estimation of the mean absorbed dose to the lungs based on pretreatment diagnostic (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) imaging should prevent this, with administered activities adjusted accordingly. The accuracy of (99m)Tc-MAA-based lung absorbed dose estimates was evaluated and compared to absorbed dose estimates based on pretreatment diagnostic (166)Ho-microsphere imaging and to the actual lung absorbed doses after (166)Ho radioembolization. This prospective clinical study included 14 patients with chemorefractory, unresectable liver metastases treated with (166)Ho radioembolization. (99m)Tc-MAA-based and (166)Ho-microsphere-based estimation of lung absorbed doses was performed on pretreatment diagnostic planar scintigraphic and SPECT/CT images. The clinical analysis was preceded by an anthropomorphic torso phantom study with simulated lung shunt fractions of 0 to 30 % to determine the accuracy of the image-based lung absorbed dose estimates after (166)Ho radioembolization. In the phantom study, (166)Ho SPECT/CT-based lung absorbed dose estimates were more accurate (absolute error range 0.1 to -4.4 Gy) than (166)Ho planar scintigraphy-based lung absorbed dose estimates (absolute error range 9.5 to 12.1 Gy). Clinically, the actual median lung absorbed dose was 0.02 Gy (range 0.0 to 0.7 Gy) based on posttreatment (166)Ho-microsphere SPECT/CT imaging. Lung absorbed doses estimated on the basis of pretreatment diagnostic (166)Ho-microsphere SPECT/CT imaging (median 0.02 Gy, range 0.0 to 0.4 Gy) were significantly better predictors of the actual lung absorbed doses than doses estimated on the basis of (166)Ho-microsphere planar scintigraphy (median 10.4 Gy, range 4.0 to 17.3 Gy; p < 0.001), (99m)Tc-MAA SPECT/CT imaging (median 2.5 Gy, range 1.2 to 12.3 Gy; p < 0.001), and (99m)Tc-MAA planar scintigraphy (median 5.5 Gy, range 2.3 to 18.2 Gy; p < 0.001). In clinical practice, lung absorbed doses are significantly overestimated by pretreatment diagnostic (99m)Tc-MAA imaging. Pretreatment diagnostic (166)Ho-microsphere SPECT/CT imaging accurately predicts lung absorbed doses after (166)Ho radioembolization.

SPECT imaging in evaluating extent of malignant external otitis: case report

DOE Office of Scientific and Technical Information (OSTI.GOV)

English, R.J.; Tu'Meh, S.S.; Piwnica-Worms, D.

1987-03-01

Otitis externa, a benign inflammatory process of the external auditory canal, is general responsive to local therapy. Some patients however, develop a less controllable disease leading to chondritis and osteomyelitis of the base of the skull. The direct invasive characteristic of the disease has led to the descriptive term malignant external otitis (MEO), more appropriately called necrotizing or invasive external otitis. Malignant external otitis is caused by an aggressive pseudomonas or proteus infection that almost exclusively occurs in elderly diabetic patients. The primary imaging modalities previously used in the diagnosis and evaluation of MEO were standard planar scintigraphic techniques withmore » technetium-99M (/sup 99m/Tc) bone agents and gallium-67 (/sup 67/Ga), and pluridirectional tomography. The advent of high resolution computed tomography (CT) effectively allowed demonstration of the soft tissue extension and bone destruction associated with MEO, but still suffered from the low sensitivity constraints of all radiographic techniques in determining early inflammatory bone involvement. Recent work suggests that scintigraphic detection of MEO with /sup 99m/Tc-MDP and /sup 67/Ga, combined with the cross-sectional resolution of single photon emission computed tomography (SPECT) may be of value in planning treatment of this inflammatory condition.« less

Simulation study of the second-generation MR-compatible SPECT system based on the inverted compound-eye gamma camera design

NASA Astrophysics Data System (ADS)

Lai, Xiaochun; Meng, Ling-Jian

2018-02-01

In this paper, we present simulation studies for the second-generation MRI compatible SPECT system, MRC-SPECT-II, based on an inverted compound eye (ICE) gamma camera concept. The MRC-SPECT-II system consists of a total of 1536 independent micro-pinhole-camera-elements (MCEs) distributed in a ring with an inner diameter of 6 cm. This system provides a FOV of 1 cm diameter and a peak geometrical efficiency of approximately 1.3% (the typical levels of 0.1%-0.01% found in modern pre-clinical SPECT instrumentations), while maintaining a sub-500 μm spatial resolution. Compared to the first-generation MRC-SPECT system (MRC-SPECT-I) (Cai 2014 Nucl. Instrum. Methods Phys. Res. A 734 147-51) developed in our lab, the MRC-SPECT-II system offers a similar resolution with dramatically improved sensitivity and greatly reduced physical dimension. The latter should allow the system to be placed inside most clinical and pre-clinical MRI scanners for high-performance simultaneous MRI and SPECT imaging.

Evaluation of 209At as a theranostic isotope for 209At-radiopharmaceutical development using high-energy SPECT

NASA Astrophysics Data System (ADS)

Crawford, J. R.; Robertson, A. K. H.; Yang, H.; Rodríguez-Rodríguez, C.; Esquinas, P. L.; Kunz, P.; Blinder, S.; Sossi, V.; Schaffer, P.; Ruth, T. J.

2018-02-01

The development of alpha-emitting radiopharmaceuticals using 211At requires quantitative determination of the time-dependent nature of the 211At biodistribution. However, imaging-based methods for acquiring this information with 211At have not found wide-spread use because of its low abundance of decay emissions suitable for external detection. In this publication we demonstrate the theranostic abilities of the 211At/209At isotope pair and present the first-ever 209At SPECT images. The VECTor microSPECT/PET/CT scanner was used to image 209At with a collimator suitable for the 511 keV annihilation photons of PET isotopes. Data from distinct photopeaks of the 209At energy spectrum (195 keV (22.6%), 239 keV (12.4 %), 545 keV (91.0 %), a combined 782/790 keV peak (147 %), and 209Po x-rays (139.0 %)) were independently evaluated for use in image reconstructions using Monte Carlo (GATE) simulations and phantom studies. 209At-imaging in vivo was demonstrated in a healthy mouse injected with 10 MBq of free [209At]astatide. Image-based measurements of 209At uptake in organs of interest—acquired in 5 min intervals—were compared to ex vivo gamma counter measurements of the same organs. Simulated and measured data indicated that—due to the large amount of scatter from high energy (>750 keV) gammas—reconstructed images using the x-ray peak outperformed those obtained from other peaks in terms of image uniformity and spatial resolution, determined to be  <0.85 mm. 209At imaging using the x-ray peak revealed a biodistribution that matched the known distribution of free astatide, and in vivo image-based measurements of 209At uptake in organs of interest matched ex vivo measurements within 10%. We have acquired the first 209At SPECT images and demonstrated the ability of quantitative SPECT imaging with 209At to accurately determine astatine biodistributions with high spatial and temporal resolution.

Comparison of SPECT/CT and Planar Lympho-scintigraphy in Sentinel Node Biopsies of Oral Cavity Squamous Cell Carcinomas.

PubMed

Chandra, Piyush; Dhake, Sanket; Shah, Sneha; Agrawal, Archi; Purandare, Nilendu; Rangarajan, Venkatesh

2017-01-01

Evidence supporting the use of Sentinel node biopsy (SNB) for nodal staging of early oral squamous cell carcinomas (OSCC) appears to be very promising. Pre-operative lymphatic mapping using planar lymphoscinitigraphy (PL) with or without SPECT/CT in the SNB procedure is useful in sentinel node localization and for planning appropriate surgery. Recently, a large prospective multi-centric study evaluating SNB in cutaneous melanoma, breast and pelvic malignancies, demonstrated that adding SPECT to PL leads to surgical adjustments in a considerable number of patients. Our aim of this study was to evaluate the incremental value of additional SPECT/CT over PL alone in SNB for OSCC. This was a retrospective analysis of 44 patients (40- tongue, 4- buccal mucosa) with T1-T2, clinically N0 oral cavity SCC who underwent sentinel node biopsy procedure. PL and SPECT lymphoscinitigraphy images were compared for pre-operative mapping of sentinel nodes. Using a handheld gamma probe, a total of 179 sentinel nodes were harvested, with a mean of 4.06 per patient. PL revealed 75 hotspots with a mean of 1.70 per patient, and SPECT/CT revealed 92 hotspots with a mean of 2.09 per patient. Additional hotpots were identified in 14 patients on SPECT/CT, which included 4 patients, where PL did not detect any sentinel nodes. Pre-operative SPECT/CT in addition to planar lympho-scinitigraphy in sentinel node biopsies of oral cavity SCC detects more number of sentinel nodes compared to planar imaging alone. The higher sensitivity of SPECT combined with better anatomical localization using diagnostic CT may further improve the precision of SNB procedure.

The predictive value of single-photon emission computed tomography/computed tomography for sentinel lymph node localization in head and neck cutaneous malignancy.

PubMed

Remenschneider, Aaron K; Dilger, Amanda E; Wang, Yingbing; Palmer, Edwin L; Scott, James A; Emerick, Kevin S

2015-04-01

Preoperative localization of sentinel lymph nodes in head and neck cutaneous malignancies can be aided by single-photon emission computed tomography/computed tomography (SPECT/CT); however, its true predictive value for identifying lymph nodes intraoperatively remains unquantified. This study aims to understand the sensitivity, specificity, and positive and negative predictive values of SPECT/CT in sentinel lymph node biopsy for cutaneous malignancies of the head and neck. Blinded retrospective imaging review with comparison to intraoperative gamma probe confirmed sentinel lymph nodes. A consecutive series of patients with a head and neck cutaneous malignancy underwent preoperative SPECT/CT followed by sentinel lymph node biopsy with a gamma probe. Two nuclear medicine physicians, blinded to clinical data, independently reviewed each SPECT/CT. Activity within radiographically defined nodal basins was recorded and compared to intraoperative gamma probe findings. Sensitivity, specificity, and negative and positive predictive values were calculated with subgroup stratification by primary tumor site. Ninety-two imaging reads were performed on 47 patients with cutaneous malignancy who underwent SPECT/CT followed by sentinel lymph node biopsy. Overall sensitivity was 73%, specificity 92%, positive predictive value 54%, and negative predictive value 96%. The predictive ability of SPECT/CT to identify the basin or an adjacent basin containing the single hottest node was 92%. SPECT/CT overestimated uptake by an average of one nodal basin. In the head and neck, SPECT/CT has higher reliability for primary lesions of the eyelid, scalp, and cheek. SPECT/CT has high sensitivity, specificity, and negative predictive value, but may overestimate relevant nodal basins in sentinel lymph node biopsy. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

Low-dose computed tomography scans with automatic exposure control for patients of different ages undergoing cardiac PET/CT and SPECT/CT.

PubMed

Yang, Ching-Ching; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin; Liu, Shu-Hsin

2017-06-01

This study aimed to evaluate the efficacy of automatic exposure control (AEC) in order to optimize low-dose computed tomography (CT) protocols for patients of different ages undergoing cardiac PET/CT and single-photon emission computed tomography/computed tomography (SPECT/CT). One PET/CT and one SPECT/CT were used to acquire CT images for four anthropomorphic phantoms representative of 1-year-old, 5-year-old and 10-year-old children and an adult. For the hybrid systems investigated in this study, the radiation dose and image quality of cardiac CT scans performed with AEC activated depend mainly on the selection of a predefined image quality index. Multiple linear regression methods were used to analyse image data from anthropomorphic phantom studies to investigate the effects of body size and predefined image quality index on CT radiation dose in cardiac PET/CT and SPECT/CT scans. The regression relationships have a coefficient of determination larger than 0.9, indicating a good fit to the data. According to the regression models, low-dose protocols using the AEC technique were optimized for patients of different ages. In comparison with the standard protocol with AEC activated for adult cardiac examinations used in our clinical routine practice, the optimized paediatric protocols in PET/CT allow 32.2, 63.7 and 79.2% CT dose reductions for anthropomorphic phantoms simulating 10-year-old, 5-year-old and 1-year-old children, respectively. The corresponding results for cardiac SPECT/CT are 8.4, 51.5 and 72.7%. AEC is a practical way to reduce CT radiation dose in cardiac PET/CT and SPECT/CT, but the AEC settings should be determined properly for optimal effect. Our results show that AEC does not eliminate the need for paediatric protocols and CT examinations using the AEC technique should be optimized for paediatric patients to reduce the radiation dose as low as reasonably achievable.

Synthesis and Biological Evaluation of Cyclic [99mTc]-HYNIC-CGPRPPC as a Fibrin-Binding Peptide for Molecular Imaging of Thrombosis and Its Comparison with [99mTc]-HYNIC-GPRPP.

PubMed

Rezaeianpour, Sedigheh; Bozorgi, Atefeh Hajiagha; Moghimi, Abolghasem; Almasi, Ameneh; Balalaie, Saeed; Ramezanpour, Sorour; Nasoohi, Sanaz; Mazidi, Seyed Mohammad; Geramifar, Parham; Bitarafan-Rajabi, Ahmad; Shahhosseini, Soraya

2017-04-01

Many patients worldwide suffer from cardiovascular diseases for which an underlying factor is thrombosis. Devising a molecular imaging technique for early detection of thrombosis in a clinical setting is highly recommended. Because fibrin is a major constituent of clots and is present in all types of thrombi but absent in circulation, it is a highly specific and sensitive target for molecular imaging of thrombi. It is assumed that cyclization of peptides will improve the receptor binding affinity and stability of the peptide. In the present study, we have developed linear and cyclic fibrin-binding peptides for thrombus imaging and compared their biological properties. Linear HYNIC-GPRPP and cyclic HYNIC-CGPRPPC peptides were synthesized using a standard Fmoc strategy and radiolabeled with Tc-99m. The stability of the radiolabeled peptides in human plasma and their affinity for fibrin and blood clots were determined. Blood clearance and biodistribution were evaluated in rats and mice, respectively. The peptide with the highest affinity was injected to a live rabbit femoral thrombosis model, and scintigraphic images were obtained. In vitro studies show that peptides are stable in human plasma and have a high affinity for human fibrin. They also demonstrated fast blood clearance in rats and high thrombus uptake in the Balb/c mice femoral thrombosis model. Femoral thrombosis was visualized 30 min postinjection of cyclic peptide in a live rabbit model using single photon emission computed tomography (SPECT)/X-ray computed tomography. The results indicate that the cyclic peptide is a promising agent for molecular imaging of fibrin using SPECT.

Hybrid SPECT-CT and PET-CT imaging of differentiated thyroid carcinoma.

PubMed

Wong, K K; Zarzhevsky, N; Cahill, J M; Frey, K A; Avram, A M

2009-10-01

Hybrid imaging modalities such as radioiodine single photon emission CT with integrated CT ((131)I SPECT-CT) and 2-(fluorine-18)-fluoro-2-deoxy-D-glucose positron emission tomography with integrated CT (FDG PET-CT) allow the rapid and efficient fusion of functional and anatomic images, and provide diagnostic information that may influence management decisions in patients with differentiated thyroid carcinoma (DTC). Diagnostic localisation and therapy of these tumours are dependent upon their capacity to concentrate radioiodine ((131)I) via uptake through the sodium-iodide symporter and retention within the tumour. The prognosis for most patients with DTC is favourable, although controversy exists regarding the role of post-operative (131)I therapy in patients at low-risk for disease. Accurate identification of functional thyroid tissue (benign or malignant) using diagnostic (131)I planar scintigraphy complemented by SPECT-CT imaging enables the completion of post-operative staging and patient risk stratification prior to (131)I therapy administration. In patients with non-iodine-avid tumours (negative (131)I scan but elevated thyroglobulin indicative of persistent or recurrent disease), FDG PET-CT is used to identify tumours with enhanced glucose metabolism and to localise the source of thyroglobulin production. The CT component of this hybrid technology provides anatomic localisation of activity and allows CT-based attenuation correction of PET images. Images from 15 patients illustrate the applications of (131)I SPECT-CT and FDG PET-CT.

Kit formulated asialoglycoprotein receptor targeting tracer based on copolymer for liver SPECT imaging.

PubMed

Liu, Chang; Guo, Zhide; Zhang, Pu; Song, Manli; Zhao, Zuoquan; Wu, Xiaowei; Zhang, Xianzhong

2014-08-01

Specific targeting of galactose-carrying molecule to ASGP-R in normal hepatocytes has been demonstrated before. In this study, galactosyl polystyrene was synthesized from controllable ratio of functional monomers and radio-labelled with (99m)Tc by formulated kit for SPECT imaging of hepatic function. p(VLA-co-VNI)(46:54) was synthesized by free-radical copolymerization initiated by AIBN, purified by dialysis, lyophilized to kit with Tricine and TPPTS as co-ligands for (99m)Tc labeling. Radiotracer (99m)Tc-p(VLA-co-VNI)(46:54)(Tricine)(TPPTS) was prepared and evaluated by in vitro stability, in vivo metabolism, ex vivo biodistribution and microSPECT/CT imaging in normal KM mice. MicroSPECT/CT and microMRI imaging were also performed in C57BL/b6 mice with xenograft hepatic carcinoma for hepatic function evaluation. (99m)Tc-p(VLA-co-VNI)(46:54)(Tricine)(TPPTS) was obtained in high radio chemical purity (RCP) (>99%) by using instant kit without further purification and excellent in vitro and in vivo stability. The result of biodistribution showed that liver had high uptake (90.49±10.68 ID%/g) at 30 min after injection and was blocked significantly by cold copolymer. MicroSPECT imaging in normal KM mice at 1h and 4h after injection showed good liver retention and targeting properties. Significant defect of activity was observed in the tumor site which was confirmed by MRI imaging. (99m)Tc-p(VLA-co-VNI)(46:54)(Tricine)(TPPTS) with lower ratio of targeting moiety has no observable effect on the specific binding affinity and liver uptake. This makes it possible to introduce more imaging units for multi-modality imaging. Furthermore, the instant kit preparation of (99m)Tc-labeling provides great potential for the evaluation of hepatocyte function in clinical application. Copyright © 2014 Elsevier Inc. All rights reserved.

Tc-99m Radiolabeled Peptide p5 + 14 is an Effective Probe for SPECT Imaging of Systemic Amyloidosis.

PubMed

Kennel, Stephen J; Stuckey, Alan; McWilliams-Koeppen, Helen P; Richey, Tina; Wall, Jonathan S

2016-08-01

Systemic peripheral amyloidosis is a rare disease in which misfolded proteins deposit in various organs. We have previously developed I-124 labeled peptide p5 + 14 as a tracer for positron emission tomography imaging of amyloid in patients. In this report, we now document the labeling efficiency, bioactivity, and stability of Tc-99m labeled p5 + 14 for single-photon emission computed tomography (SPECT) imaging of amyloidosis, validated in a mouse model of systemic amyloidosis. Radiochemical yield, purity, and biological activity of [(99m)Tc]p5 + 14 were documented by instant thin-layer chromatography (ITLC), SDS-PAGE and a quantitative amyloid fibril pulldown assay. The efficacy and stability were documented in serum amyloid protein A (AA) amyloid-bearing or wild-type (WT) control mice imaged with SPECT/X-ray computed tomography (CT) at two time points. The uptake and retention of [(99m)Tc]p5 + 14 in hepatosplenic amyloid was evaluated using region of interest (ROI) and tissue counting measurements. Tc-99m p5 + 14 was produced with a radiochemical yield of 75 % with greater than 90 % purity and biological activity comparable to that of radioiodinated peptide. AA amyloid was visualized by SPECT/CT imaging with specific uptake seen in amyloid-laden organs at levels ∼5 folds higher than in healthy mice. ROI analyses of decay-corrected SPECT/CT images showed <20 % loss of radiolabel from the 1 to 4 h imaging time points. Biodistribution data confirmed the specificity of the probe accumulation by amyloid-laden organs as compared to non-diseased tissues. [(99m)Tc]p5 + 14 is a specific and stable radiotracer for systemic amyloid in mice and may provide a convenient and inexpensive alternative to imaging of peripheral amyloidosis in patients.

Vertebral Uptake of Tc-99m Macroaggregated Albumin (MAA) with SPECT/CT Occurring in Superior Vena Cava Obstruction.

PubMed

Karls, Shawn; Hassoun, Hani; Derbekyan, Vilma

2016-09-01

A 67-year-old male presented with dyspnea for which lung scintigraphy was ordered to rule out pulmonary embolus. Planar images demonstrated abnormal midline uptake of Tc-99m macroaggregated albumin, which SPECT/CT localized to several thoracic vertebrae. Thoracic vertebral uptake on perfusion lung scintigraphy was previously described on planar imaging. Radionuclide venography and contrast-enhanced CT subsequently demonstrated superior vena cava (SVC) obstruction with collateralization through the azygous/hemiazygous system and vertebral venous plexus. SPECT/CT differentiated residual esophageal/tracheal ventilation activity, a clinically insignificant finding, from vertebral uptake indicative of SVC obstruction, a potentially life-threatening condition.

Brain single-photon emission CT physics principles.

PubMed

Accorsi, R

2008-08-01

The basic principles of scintigraphy are reviewed and extended to 3D imaging. Single-photon emission computed tomography (SPECT) is a sensitive and specific 3D technique to monitor in vivo functional processes in both clinical and preclinical studies. SPECT/CT systems are becoming increasingly common and can provide accurately registered anatomic information as well. In general, SPECT is affected by low photon-collection efficiency, but in brain imaging, not all of the large FOV of clinical gamma cameras is needed: The use of fan- and cone-beam collimation trades off the unused FOV for increased sensitivity and resolution. The design of dedicated cameras aims at increased angular coverage and resolution by minimizing the distance from the patient. The corrections needed for quantitative imaging are challenging but can take advantage of the relative spatial uniformity of attenuation and scatter. Preclinical systems can provide submillimeter resolution in small animal brain imaging with workable sensitivity.

SpectraPLOT, Visualization Package with a User-Friendly Graphical Interface

NASA Astrophysics Data System (ADS)

Sebald, James; Macfarlane, Joseph; Golovkin, Igor

2017-10-01

SPECT3D is a collisional-radiative spectral analysis package designed to compute detailed emission, absorption, or x-ray scattering spectra, filtered images, XRD signals, and other synthetic diagnostics. The spectra and images are computed for virtual detectors by post-processing the results of hydrodynamics simulations in 1D, 2D, and 3D geometries. SPECT3D can account for a variety of instrumental response effects so that direct comparisons between simulations and experimental measurements can be made. SpectraPLOT is a user-friendly graphical interface for viewing a wide variety of results from SPECT3D simulations, and applying various instrumental effects to the simulated images and spectra. We will present SpectraPLOT's ability to display a variety of data, including spectra, images, light curves, streaked spectra, space-resolved spectra, and drilldown plasma property plots, for an argon-doped capsule implosion experiment example. Future SpectraPLOT features and enhancements will also be discussed.

Imaging of striatal dopamine transporters in rat brain with single pinhole SPECT and co-aligned MRI is highly reproducible.

PubMed

Booij, Jan; de Bruin, Kora; de Win, Maartje M L; Lavini, Cristina; den Heeten, Gerard J; Habraken, Jan B A

2003-08-01

A recently developed pinhole high-resolution SPECT system was used to measure striatal to non-specific binding ratios in rats (n = 9), after injection of the dopamine transporter ligand (123)I-FP-CIT, and to assess its test/retest reproducibility. For co-alignment purposes, the rat brain was imaged on a 1.5 Tesla clinical MRI scanner using a specially developed surface coil. The SPECT images showed clear striatal uptake. On the MR images, cerebral and extra-cerebral structures could be easily delineated. The mean striatal to non-specific [(123)I]FP-CIT binding ratios of the test/retest studies were 1.7 +/- 0.2 and 1.6 +/- 0.2, respectively. The test/retest variability was approximately 9%. We conclude that the assessment of striatal [(123)I]FP-CIT binding ratios in rats is highly reproducible.

Differential diagnosis of bilateral parietal abnormalities in I-123 IMP SPECT imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuwabara, Y.; Ichiya, Y.; Otsuka, M.

1990-12-01

This report discusses the clinical significance of bilateral parietal abnormalities on I-123 IMP SPECT imaging in 158 patients with cerebral disorders. This pattern was seen in 15 out of 21 patients with Alzheimer's disease; it was also seen in 4 out of 5 patients with Parkinson's disease with dementia, in 3 out of 17 patients with vascular dementia, in 1 out of 36 patients with cerebral infarction without dementia, in 1 out of 2 patients with hypoglycemia, and in 1 out of 2 patients with CO intoxication. Detection of bilateral parietal abnormalities is a useful finding in the diagnosis ofmore » Alzheimer's disease, but one should keep in mind that other cerebral disorders may also show a similar pattern with I-123 IMP SPECT imaging.« less

Fuzzy C-mean clustering on kinetic parameter estimation with generalized linear least square algorithm in SPECT

NASA Astrophysics Data System (ADS)

Choi, Hon-Chit; Wen, Lingfeng; Eberl, Stefan; Feng, Dagan

2006-03-01

Dynamic Single Photon Emission Computed Tomography (SPECT) has the potential to quantitatively estimate physiological parameters by fitting compartment models to the tracer kinetics. The generalized linear least square method (GLLS) is an efficient method to estimate unbiased kinetic parameters and parametric images. However, due to the low sensitivity of SPECT, noisy data can cause voxel-wise parameter estimation by GLLS to fail. Fuzzy C-Mean (FCM) clustering and modified FCM, which also utilizes information from the immediate neighboring voxels, are proposed to improve the voxel-wise parameter estimation of GLLS. Monte Carlo simulations were performed to generate dynamic SPECT data with different noise levels and processed by general and modified FCM clustering. Parametric images were estimated by Logan and Yokoi graphical analysis and GLLS. The influx rate (K I), volume of distribution (V d) were estimated for the cerebellum, thalamus and frontal cortex. Our results show that (1) FCM reduces the bias and improves the reliability of parameter estimates for noisy data, (2) GLLS provides estimates of micro parameters (K I-k 4) as well as macro parameters, such as volume of distribution (Vd) and binding potential (BP I & BP II) and (3) FCM clustering incorporating neighboring voxel information does not improve the parameter estimates, but improves noise in the parametric images. These findings indicated that it is desirable for pre-segmentation with traditional FCM clustering to generate voxel-wise parametric images with GLLS from dynamic SPECT data.

The Diagnostic Efficiency of 99mTc-EDDA/HYNIC-Octreotate SPECT-CT in Comparison with 111In-Pentetrotide in the Detection of Neuroendocrine Tumours

PubMed Central

Koçyiğit Deveci, Emel; Ocak, Meltem; Bozkurt, Murat Fani; Türker, Selcan; Kabasakal, Levent; Uğur, Ömer

2013-01-01

Objective: The aim of this study was to assess the diagnostic efficiency of 99mTc-EDDA/HYNIC-Octreotate in comparison with 111Inpentetrotide scintigraphy in the detection of neuroendocrine tumors. This study also evaluates the impact of SPECT-CT hybrid imaging on somatostatin receptor scintigraphy (SRS) interpretation and clinical management of these tumors. Methods: Fourteen patients were included in the study. All patients underwent a whole body and SPECT-CT imaging with both 99mTc- EDDA/HYNIC-octreotate and 111In-pentetrotide. Images were evaluated both visually and semiquantitatively. Results: On patient basis, the diagnostic results of both studies were similar. The number of lesions detected by 99mTc- EDDA/HYNICOctreotate were higher than the number of lesions detected by 111In-pentetrotide however the difference was not significant (40/43( 93%), 36/43 (83%) p=0.109). Semiquantitative analysis showed higher tumor/organ count ratios for both whole-body and SPECT 99mTc- EDDA/HYNIC-Octreotate scans. Conclusion: The results of this study suggested that, 99mTc- EDDA/HYNIC-Octreotate may be a better alternative to 111In- pentetrotide due to high image quality and lower radiation dose. SPECT/CT is a valuable tool for the assessment of neuroendocrine tumors by providing the precise anatomic localization of scintigraphic findings thus improving lesion detectability and characterization. Conflict of interest:None declared. PMID:24416622

Diagnostic accuracy and functional parameters of myocardial perfusion scintigraphy using accelerated cardiac acquisition with IQ SPECT technique in comparison to conventional imaging.

PubMed

Pirich, Christian; Keinrath, Peter; Barth, Gabriele; Rendl, Gundula; Rettenbacher, Lukas; Rodrigues, Margarida

2017-03-01

IQ SPECT consists of a new pinhole-like collimator, cardio-centric acquisition, and advanced 3D iterative SPECT reconstruction. The aim of this paper was to compare diagnostic accuracy and functional parameters obtained with IQ SPECT versus conventional SPECT in patients undergoing myocardial perfusion scintigraphy with adenosine stress and at rest. Eight patients with known or suspected coronary artery disease underwent [99mTc] tetrofosmin gated SPECT. Acquisition was performed on a Symbia T6 equipped with IQ SPECT and on a conventional gamma camera system. Gated SPECT data were used to calculate functional parameters. Scores analysis was performed on a 17-segment model. Coronary angiography and clinical follow-up were considered as diagnostic reference standard. Mean acquisition time was 4 minutes with IQ SPECT and 21 minutes with conventional SPECT. Agreement degree on the diagnostic accuracy between both systems was 0.97 for stress studies, 0.91 for rest studies and 0.96 for both studies. Perfusion abnormalities scores obtained by using IQ SPECT and conventional SPECT were not significant different: SSS, 9.7±8.8 and 10.1±6.4; SRS, 7.1±6.1 and 7.5±7.3; SDS, 4.0±6.1 and 3.9±4.3, respectively. However, a significant difference was found in functional parameters derived from IQ SPECT and conventional SPECT both after stress and at rest. Mean LVEF was 8% lower using IQ SPECT. Differences in LVEF were found in patients with normal LVEF and patients with reduced LVEF. Functional parameters using accelerated cardiac acquisition with IQ SPECT are significantly different to those obtained with conventional SPECT, while agreement for clinical interpretation of myocardial perfusion scintigraphy with both techniques is high.

High Sensitivity SPECT for Small Animals and Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, Gregory S.

Imaging systems using single gamma-ray emitting radioisotopes typically implement collimators in order to form the images. However, a tradeoff in sensitivity is inherent in the use of collimators, and modern preclinical single-photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma-rays (<0.3%). We have built a collimator-less system, which can reach sensitivity of 40% for 99mTc imaging, while still producing images of sufficient spatial resolution for certain applications in thin objects such as mice, small plants, and well plates used for in vitro experiments.

Using the Wiener estimator to determine optimal imaging parameters in a synthetic-collimator SPECT system used for small animal imaging

NASA Astrophysics Data System (ADS)

Lin, Alexander; Johnson, Lindsay C.; Shokouhi, Sepideh; Peterson, Todd E.; Kupinski, Matthew A.

2015-03-01

In synthetic-collimator SPECT imaging, two detectors are placed at different distances behind a multi-pinhole aperture. This configuration allows for image detection at different magnifications and photon energies, resulting in higher overall sensitivity while maintaining high resolution. Image multiplexing the undesired overlapping between images due to photon origin uncertainty may occur in both detector planes and is often present in the second detector plane due to greater magnification. However, artifact-free image reconstruction is possible by combining data from both the front detector (little to no multiplexing) and the back detector (noticeable multiplexing). When the two detectors are used in tandem, spatial resolution is increased, allowing for a higher sensitivity-to-detector-area ratio. Due to variability in detector distances and pinhole spacings found in synthetic-collimator SPECT systems, a large parameter space must be examined to determine optimal imaging configurations. We chose to assess image quality based on the task of estimating activity in various regions of a mouse brain. Phantom objects were simulated using mouse brain data from the Magnetic Resonance Microimaging Neurological Atlas (MRM NeAt) and projected at different angles through models of a synthetic-collimator SPECT system, which was developed by collaborators at Vanderbilt University. Uptake in the different brain regions was modeled as being normally distributed about predetermined means and variances. We computed the performance of the Wiener estimator for the task of estimating activity in different regions of the mouse brain. Our results demonstrate the utility of the method for optimizing synthetic-collimator system design.

Variability of serial same-day left ventricular ejection fraction using quantitative gated SPECT.

PubMed

Vallejo, Enrique; Chaya, Hugo; Plancarte, Gerardo; Victoria, Diana; Bialostozky, David

2002-01-01

The accuracy of quantitative gated single photon emission computed tomography (SPECT) (QGS) and the potential limitations for estimation of left ventricular ejection fraction (LVEF) have been extensively evaluated. However, few studies have focused on the serial variability of QGS. This study was conducted to assess the serial variability of QGS for determination of LVEF between 2 sequential technetium 99m sestamibi-gated SPECT acquisitions at rest in both healthy and unhealthy subjects. The study population consisted of 2 groups: group I included 21 volunteers with a low likelihood of CAD, and group II included 22 consecutive patients with documented CAD. Both groups underwent serial SPECT imaging. The overall correlation between sequential images was high (r = 0.94, SEE = 5.3%), and the mean serial variability of LVEF was 5.15% +/- 3.51%. Serial variability was lower for images with high counts (3.45% +/- 3.23%) than for images with low counts (6.85% +/- 3.77%). The mean serial variability was not different between normal and abnormal high-dose images (3.0% +/- 1.56% vs 3.9% +/- 2.77%). However, mean serial variability for images derived from abnormal low-dose images was significantly greater than that derived from normal low-dose images (9.6% +/- 2.22% vs 3.1% +/- 2.12%, P <.05). Although QGS is an efficacious method to approximate LVEF values and is extremely valuable for incremental risk stratification of patients with coronary artery disease, it has significant variability in the estimation of LVEF on serial images. This should be taken into account when used for serial evaluation of LVEF.

Improved Diagnostic Accuracy of SPECT Through Statistical Analysis and the Detection of Hot Spots at the Primary Sensorimotor Area for the Diagnosis of Alzheimer Disease in a Community-Based Study: "The Osaki-Tajiri Project".

PubMed

Kaneta, Tomohiro; Nakatsuka, Masahiro; Nakamura, Kei; Seki, Takashi; Yamaguchi, Satoshi; Tsuboi, Masahiro; Meguro, Kenichi

2016-01-01

SPECT is an important diagnostic tool for dementia. Recently, statistical analysis of SPECT has been commonly used for dementia research. In this study, we evaluated the accuracy of visual SPECT evaluation and/or statistical analysis for the diagnosis (Dx) of Alzheimer disease (AD) and other forms of dementia in our community-based study "The Osaki-Tajiri Project." Eighty-nine consecutive outpatients with dementia were enrolled and underwent brain perfusion SPECT with 99mTc-ECD. Diagnostic accuracy of SPECT was tested using 3 methods: visual inspection (SPECT Dx), automated diagnostic tool using statistical analysis with easy Z-score imaging system (eZIS Dx), and visual inspection plus eZIS (integrated Dx). Integrated Dx showed the highest sensitivity, specificity, and accuracy, whereas eZIS was the second most accurate method. We also observed that a higher than expected rate of SPECT images indicated false-negative cases of AD. Among these, 50% showed hypofrontality and were diagnosed as frontotemporal lobar degeneration. These cases typically showed regional "hot spots" in the primary sensorimotor cortex (ie, a sensorimotor hot spot sign), which we determined were associated with AD rather than frontotemporal lobar degeneration. We concluded that the diagnostic abilities were improved by the integrated use of visual assessment and statistical analysis. In addition, the detection of a sensorimotor hot spot sign was useful to detect AD when hypofrontality is present and improved the ability to properly diagnose AD.

Estimation of sensitivity and specificity of brain magnetic resonance imaging and single photon emission computed tomography in the diagnosis of olfactory dysfunction after head traumas.

PubMed

Atighechi, Saeid; Zolfaghari, Aliasghar; Baradaranfar, Mohammadhossein; Dadgarnia, Mohammadhossein

2013-01-01

Olfactory dysfunction has an incidence of 5-10% after head injury. Several objective and subjective tests had been proposed. Recent studies showed that brain single photon emission computed tomography (SPECT) and brain magnetic resonance imaging (MRI) have good diagnostic value in this era in which the most common sites of involvement were olfactory bulb and olfactory nerve in MRI and frontal lobe in SPECT. This study aimed to estimate the sensitivity and specificity of brain MRI and brain SPECT in the diagnosis of traumatic hyposmia and anosmia. From February 2009 to March 2011, 63 patients with head injury and smell complaint were selected for this study. Using an identification test and a threshold smell test, 28 were anosmic and 27 had hyposmia and the remaining 8 were normosmic. All of them underwent brain MRI and SPECT. The sensitivity of SPECT was 81.5 and 85.7% in hyposmia and anosmia, respectively. Its specificity was 87.5% in anosmia and 87.7% in anosmia. MRI sensitivity was 66.7% in hyposmia but 82.1% in anosmia. Its specificity was 85.7% in anosmia and 87.7% in anosmia. If MRI and SPECT were considered together, the sensitivity was 92.3% in hyposmia and 92% in anosmia, but the specificity was 87% in both cases. According to our study, both brain MRI and SPECT have high sensitivity and specificity in the diagnosis of traumatic anosmia, although brain SPECT is slightly superior to MRI. If the two techniques are applied together, the accuracy will be increased.

Tracing and quantification of pharmaceuticals using MR imaging and spectroscopy at clinical MRI system

NASA Astrophysics Data System (ADS)

Jeong, Eun-Kee; Liu, Xin; Shi, Xianfeng; Yu, Y. Bruce; Lu, Zeng-Rong

2012-10-01

Magnetic resonance imaging (MRI) and spectroscopy (MRS) is very powerful modality for imaging and localized investigation of biological tissue. Medical MRI measures nuclear magnetization of the water protons, which consists of 70 % of our body. MRI provides superior contrast among different soft tissues to all other existing medical imaging modalities, including ultrasound, X-ray CT, PET, and SPECT. In principle, MRI/S may be an ideal non-invasive tool for drug delivery research. However, because of its low sensitivity, a large dose is required for tracing pharmaceuticals. Therefore, its use for imaging of pharmaceuticals is very limited mostly to molecules that contain a paramagnetic metal ion, such as gadolinium (Gd3+) and manganese (Mn2+). The paramagnetic metal ion provides a large fluctuating magnetic field at the proton in the water molecule via a coordinate site. The measurement of local drug concentration is the first step for further quantification. Local concentration of the paramagnetic-ion based MRI contrast agent can be indirectly measured via the change in the water signal intensity. 19F MRI/S of fluorinated complex may be an option for drug delivery and tracing agent, because the fluorinated molecule may be directly detected due to its large magnetic moment (94 % of proton) and 100 % abundance.

A parallel Monte Carlo code for planar and SPECT imaging: implementation, verification and applications in (131)I SPECT.

PubMed

Dewaraja, Yuni K; Ljungberg, Michael; Majumdar, Amitava; Bose, Abhijit; Koral, Kenneth F

2002-02-01

This paper reports the implementation of the SIMIND Monte Carlo code on an IBM SP2 distributed memory parallel computer. Basic aspects of running Monte Carlo particle transport calculations on parallel architectures are described. Our parallelization is based on equally partitioning photons among the processors and uses the Message Passing Interface (MPI) library for interprocessor communication and the Scalable Parallel Random Number Generator (SPRNG) to generate uncorrelated random number streams. These parallelization techniques are also applicable to other distributed memory architectures. A linear increase in computing speed with the number of processors is demonstrated for up to 32 processors. This speed-up is especially significant in Single Photon Emission Computed Tomography (SPECT) simulations involving higher energy photon emitters, where explicit modeling of the phantom and collimator is required. For (131)I, the accuracy of the parallel code is demonstrated by comparing simulated and experimental SPECT images from a heart/thorax phantom. Clinically realistic SPECT simulations using the voxel-man phantom are carried out to assess scatter and attenuation correction.

High-sensitivity brain SPECT system using cadmium telluride (CdTe) semiconductor detector and 4-pixel matched collimator.

PubMed

Suzuki, Atsuro; Takeuchi, Wataru; Ishitsu, Takafumi; Tsuchiya, Katsutoshi; Morimoto, Yuichi; Ueno, Yuichiro; Kobashi, Keiji; Kubo, Naoki; Shiga, Tohru; Tamaki, Nagara

2013-11-07

For high-sensitivity brain imaging, we have developed a two-head single-photon emission computed tomography (SPECT) system using a CdTe semiconductor detector and 4-pixel matched collimator (4-PMC). The term, '4-PMC' indicates that the collimator hole size is matched to a 2 × 2 array of detector pixels. By contrast, a 1-pixel matched collimator (1-PMC) is defined as a collimator whose hole size is matched to one detector pixel. The performance of the higher-sensitivity 4-PMC was experimentally compared with that of the 1-PMC. The sensitivities of the 1-PMC and 4-PMC were 70 cps/MBq/head and 220 cps/MBq/head, respectively. The SPECT system using the 4-PMC provides superior image resolution in cold and hot rods phantom with the same activity and scan time to that of the 1-PMC. In addition, with half the usual scan time the 4-PMC provides comparable image quality to that of the 1-PMC. Furthermore, (99m)Tc-ECD brain perfusion images of healthy volunteers obtained using the 4-PMC demonstrated acceptable image quality for clinical diagnosis. In conclusion, our CdTe SPECT system equipped with the higher-sensitivity 4-PMC can provide better spatial resolution than the 1-PMC either in half the imaging time with the same administered activity, or alternatively, in the same imaging time with half the activity.

SPECT detectors: the Anger Camera and beyond

PubMed Central

Peterson, Todd E.; Furenlid, Lars R.

2011-01-01

The development of radiation detectors capable of delivering spatial information about gamma-ray interactions was one of the key enabling technologies for nuclear medicine imaging and, eventually, single-photon emission computed tomography (SPECT). The continuous NaI(Tl) scintillator crystal coupled to an array of photomultiplier tubes, almost universally referred to as the Anger Camera after its inventor, has long been the dominant SPECT detector system. Nevertheless, many alternative materials and configurations have been investigated over the years. Technological advances as well as the emerging importance of specialized applications, such as cardiac and preclinical imaging, have spurred innovation such that alternatives to the Anger Camera are now part of commercial imaging systems. Increased computing power has made it practical to apply advanced signal processing and estimation schemes to make better use of the information contained in the detector signals. In this review we discuss the key performance properties of SPECT detectors and survey developments in both scintillator and semiconductor detectors and their readouts with an eye toward some of the practical issues at least in part responsible for the continuing prevalence of the Anger Camera in the clinic. PMID:21828904

Iofetamine hydrochloride I 123: a new radiopharmaceutical for cerebral perfusion imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Druckenbrod, R.W.; Williams, C.C.; Gelfand, M.J.

1989-01-01

Iofetamine hydrochloride I-123 permits cerebral blood perfusion imaging with single photon emission computed tomography (SPECT). SPECT is more widely available than positron emission tomography, and complements anatomic visualization with X-ray computed tomography (CT) or magnetic resonance imaging. Iofetamine is an amphetamine analog that is rapidly taken up by the lungs, then redistributed principally to the liver and brain. The precise mechanism of localization has not been determined, but is believed to result from nonspecific receptor binding. Brain uptake peaks at 30 minutes postinjection and remains relatively constant through 60 minutes. The drug is metabolized and excreted in the urine, withmore » negligible activity remaining at 48 hours. When compared with CT in stroke patients, visualization may be performed sooner after symptom onset and a larger zone of involvement may be evident with iofetamine. Localization of seizure foci and diagnosis of Alzheimer's disease may also be possible. As CT has revolutionized noninvasive imaging of brain anatomy, SPECT with iofetamine permits routine cerebral blood flow imaging. 36 references.« less

The Contribution of SPECT/CT in the Diagnosis of Stress Fracture of the Proximal Tibia.

PubMed

Okudan, Berna; Coşkun, Nazım; Arıcan, Pelin

2018-02-01

Stress fractures are injuries most commonly seen in the lower limbs and are usually caused by repetitive stress. While the distal and middle third of the tibia is the most frequent site for stress fractures (almost 50%), stress fractures of the proximal tibia is relatively rare and could be confused with other types of tibial fractures, thus altering management plans for the clinician. Early diagnosis of stress fractures is also important to avoid complications. Imaging plays an important role in the diagnosis of stress fractures, especially bone scan. Combined with single-photon emission computed tomography/computed tomography (SPECT/CT) it is an important imaging technique for stress fractures in both upper and lower extremities, and is widely preferred over other imaging techniques. In this case, we present the case of a 39-year-old male patient diagnosed with stress fracture of the proximal tibia and demonstrate the contribution of CT scan fused with SPECT imaging in the early diagnosis of stress fracture prior to other imaging modalities.

Towards Personalized Treatment of Prostate Cancer: PSMA I&T, a Promising Prostate-Specific Membrane Antigen-Targeted Theranostic Agent

PubMed Central

Chatalic, Kristell L.S.; Heskamp, Sandra; Konijnenberg, Mark; Molkenboer-Kuenen, Janneke D.M.; Franssen, Gerben M.; Clahsen-van Groningen, Marian C.; Schottelius, Margret; Wester, Hans-Jürgen; van Weerden, Wytske M.; Boerman, Otto C.; de Jong, Marion

2016-01-01

Prostate-specific membrane antigen (PSMA) is a well-established target for nuclear imaging and therapy of prostate cancer (PCa). Radiolabeled small-molecule PSMA inhibitors are excellent candidates for PCa theranostics—they rapidly and efficiently localize in tumor lesions. However, high tracer uptake in kidneys and salivary glands are major concerns for therapeutic applications. Here, we present the preclinical application of PSMA I&T, a DOTAGA-chelated urea-based PSMA inhibitor, for SPECT/CT imaging and radionuclide therapy of PCa. 111In-PSMA I&T showed dose-dependent uptake in PSMA-expressing tumors, kidneys, spleen, adrenals, lungs and salivary glands. Coadministration of 2-(phosphonomethyl)pentane-1,5-dioic acid (2-PMPA) efficiently reduced PSMA-mediated renal uptake of 111In-PSMA I&T, with the highest tumor/kidney radioactivity ratios being obtained using a dose of 50 nmol 2-PMPA. SPECT/CT clearly visualized subcutaneous tumors and sub-millimeter intraperitoneal metastases; however, high renal and spleen uptake in control mice (no 2-PMPA) interfered with visualization of metastases in the vicinity of those organs. Coadministration of 2-PMPA increased the tumor-to-kidney absorbed dose ratio during 177Lu-PSMA I&T radionuclide therapy. Hence, at equivalent absorbed dose to the tumor (36 Gy), coinjection of 2-PMPA decreased absorbed dose to the kidneys from 30 Gy to 12 Gy. Mice injected with 177Lu-PSMA I&T only, showed signs of nephrotoxicity at 3 months after therapy, whereas mice injected with 177Lu-PSMA I&T + 2-PMPA did not. These data indicate that PSMA I&T is a promising theranostic tool for PCa. PSMA-specific uptake in kidneys can be successfully tackled using blocking agents such as 2-PMPA. PMID:27162555

Development of a combined microSPECT/CT system for small animal imaging

NASA Astrophysics Data System (ADS)

Sun, Mingshan

Modern advances in the biomedical sciences have placed increased attention on small animals such as mice and rats as models of human biology and disease in biological research and pharmaceutical development. Their small size and fast breeding rate, their physiologic similarity to human, and, more importantly, the availability of sophisticated genetic manipulations, all have made mice and rats the laboratory mammals of choice in these experimental studies. However, the increased use of small animals in biomedical research also calls for new instruments that can measure the anatomic and metabolic information noninvasively with adequate spatial resolution and measurement sensitivity to facilitate these studies. This dissertation describes the engineering development of a combined single photon emission computed tomography (SPECT) and X-ray computed tomography (CT) system dedicated for small animals imaging. The system aims to obtain both the anatomic and metabolic images with submillimeter spatial resolution in a way that the data can be correlated to provide improved image quality and to offer more complete biological evaluation for biomedical studies involving small animals. The project requires development of complete microSPECT and microCT subsystems. Both subsystems are configured with a shared gantry and animal bed with integrated instrumentation for data acquisition and system control. The microCT employs a microfocus X-ray tube and a CCD-based detector for low noise, high resolution imaging. The microSPECT utilizes three semiconductor detectors coupled with pinhole collimators. A significant contribution of this dissertation project is the development of iterative algorithms with geometrical compensation that allows radionuclide images to be reconstructed at submillimeter spatial resolution, but with significantly higher detection efficiency than conventional methods. Both subsystems are capable of helical scans, offering lengthened field of view and improved axial resolution. System performance of both modalities is characterized with phantoms and animals. The microSPECT shows 0.6 mm resolution and 60 cps/MBq detection efficiency for imaging mice with 0.5 mm pinholes. The microCT achieves 120 mum spatial resolution on detector but with a relatively low detective quantum efficiency of 0.2 at the zero frequency. The combined system demonstrates a flexible platform for instrumentation development and a valuable tool for biomedical research. In summary, this dissertation describes the development of a combined SPECT/CT system for imaging the physiological function and anatomical structure in small animals.

Applications of penetrating radiation for small animal imaging

NASA Astrophysics Data System (ADS)

Hasegawa, Bruce H.; Wu, Max C.; Iwata, Koji; Hwang, Andrew B.; Wong, Kenneth H.; Barber, William C.; Dae, Michael W.; Sakdinawat, Anne E.

2002-11-01

Researchers long have relied on research involving small animals to unravel scientific mysteries in the biological sciences, and to develop new diagnostic and therapeutic techniques in the medical and health sciences. Within the past 2 decades, new techniques have been developed to manipulate the genome of the mouse, allowing the development of transgenic and knockout models of mammalian and human disease, development, and physiology. Traditionally, much biological research involving small animals has relied on the use of invasive methods such as organ harvesting, tissue sampling, and autoradiography during which the animal was sacrificed to perform a single measurement. More recently, imaging techniques have been developed that assess anatomy and physiology in the intact animal, in a way that allows the investigator to follow the progression of disease, or to monitor the response to therapeutic interventions. Imaging techniques that use penetrating radiation at millimeter or submillimeter levels to image small animals include x-ray computed tomography (microCT), single-photon emission computed tomography (microSPECT), and imaging positron emission computed tomography (microPET). MicroCT generates cross-sectional slices which reveal the structure of the object with spatial resolution in the range of 50 to 100 microns. MicroSPECT and microPET are radionuclide imaging techniques in which a radiopharmaceutical is injected into the animal that is accumulated to metabolism, blood flow, bone remodeling, tumor growth, or other biological processes. Both microSPECT and microPET offer spatial resolutions in the range of 1-2 millimeters. However, microPET records annihilation photons produced by a positron-emitting radiopharmaceutical using electronic coincidence, and has a sensitivity approximately two orders of magnitude better than microSPECT, while microSPECT is compatible with gamma-ray emitting radiopharmaceuticals that are less expensive and more readily available than those used with microPET. High-resolution dual-modality imaging systems now are being developed that combine microPET or microSPECT with microCT in a way that facilitates more direct correlation of anatomy and physiology in the same animal. Small animal imaging allows researchers to perform experiments that are not possible with conventional invasive techniques, and thereby are becoming increasingly important tools for discovery of fundamental biological information, and development of new diagnostic and therapeutic techniques in the biomedical sciences.

SPECT brain perfusion findings in mild or moderate traumatic brain injury.

PubMed

Abu-Judeh, H H; Parker, R; Aleksic, S; Singh, M L; Naddaf, S; Atay, S; Kumar, M; Omar, W; El-Zeftawy, H; Luo, J Q; Abdel-Dayem, H M

2000-01-01

The purpose of this manuscript is to present the findings in the largest series of SPECT brain perfusion imaging reported to date for mild or moderate traumatic brain injury. This is a retrospective evaluation of 228 SPECT brain perfusion-imaging studies of patients who suffered mild or moderate traumatic brain injury with or without loss of consciousness (LOC). All patients had no past medical history of previous brain trauma, neurological, or psychiatric diseases, HIV, alcohol or drug abuse. The patient population included 135 males and 93 females. The ages ranged from 11-88 years (mean 40.8). The most common complaints were characteristic of the postconcussion syndrome: headaches 139/228 (61%); dizziness 61/228 (27%); and memory problems 63/228 (28%). LOC status was reported to be positive in 121/228 (53%), negative in 41/228 (18%), and unknown for 63/228 (28%). Normal studies accounted for 52/228 (23%). For abnormal studies (176/228 or 77%) the findings were as follows: basal ganglia hypoperfusion 338 lesions (55.2%); frontal lobe hypoperfusion 146 (23.8%); temporal lobes hypoperfusion 80 (13%); parietal lobes hypoperfusion 20 (3.7%); insular and or occipital lobes hypoperfusion 28 (4.6%). Patients' symptoms correlated with the SPECT brain perfusion findings. The SPECT BPI studies in 122/228 (54%) were done early within 3 months of the date of the accident, and for the remainder, 106/228 (46%) over 3 months and less than 3 years from the date of the injury. In early imaging, 382 lesions were detected; in 92 patients (average 4.2 lesions per study) imaging after 3 months detected 230 lesions: in 84 patients (average 2.7 lesions per study). Basal ganglia hypoperfusion is the most common abnormality following mild or moderate traumatic brain injury (p = 0.006), and is more common in patients complaining of memory problem (p = 0.0005) and dizziness (p = 0.003). Early imaging can detect more lesions than delayed imaging (p = 0.0011). SPECT brain perfusion abnormalities can occur in the absence of LOC.

Technetium-99m-HMPAO SPECT, CT and MRI in the evaluation of patients with chronic traumatic brain injury: a correlation with neuropsychological performance.

PubMed

Ichise, M; Chung, D G; Wang, P; Wortzman, G; Gray, B G; Franks, W

1994-02-01

The purposes of this study were: (1) to compare 99mTc-hexamethylpropyleneamineoxime (HMPAO) SPECT with CT and MRI in chronic traumatic brain injury (TBI) patients and (2) to correlate both functional and structural neuroimaging measurements of brain damage with neuropsychological (NP) performance. Twenty-nine patients (minor TBI, n = 15 and major TBI, n = 14) and 17 normal controls (NC) underwent HMPAO SPECT, CT, MRI and NP testing. Imaging data were analyzed both visually and quantitatively. Nineteen (66%) patients showed 42 abnormalities on SPECT images, whereas 13 (45%) and 10 (34%) patients showed 29 abnormalities on MRI and 24 abnormalities on CT. SPECT detected relatively more abnormalities than CT or MRI in the minor TBI subgroup. The TBI group showed impairment on 11 tests for memory, attention and executive function. Of these, the anterior-posterior ratio (APR) correlated with six tests, whereas the ventricle-to-brain ratio (VBR), a known structural index of a poor NP outcome, correlated with only two tests. In evaluating chronic TBI patients, HMPAO SPECT, as a complement to CT or MRI, may play a useful role by demonstrating brain dysfunction in morphologically intact brain regions and providing objective evidence for some of the impaired NP performance.

SPECT imaging with Tl-201 and Ga-67 in myocardial sarcoidosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurata, C.; Sakata, K.; Taguchi, T.

1990-06-01

Two patients with myocardial sarcoidosis are presented, both of whom underwent SPECT imaging with Tl-201 and Ga-67. The first had Ga-67 myocardial uptake with a Tl-201 defect, which disappeared with corticosteroid therapy. The second had multiple Tl-201 defects without Ga-67 uptake, which persisted despite corticosteroid therapy. Therefore, the combination of Tl-201 and Ga-67 imaging may be useful for recognizing myocardial sarcoidosis and for predicting the response to corticosteroid therapy.

Micro-CT of rodents: state-of-the-art and future perspectives

PubMed Central

Clark, D. P.; Badea, C. T.

2014-01-01

Micron-scale computed tomography (micro-CT) is an essential tool for phenotyping and for elucidating diseases and their therapies. This work is focused on preclinical micro-CT imaging, reviewing relevant principles, technologies, and applications. Commonly, micro-CT provides high-resolution anatomic information, either on its own or in conjunction with lower-resolution functional imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). More recently, however, advanced applications of micro-CT produce functional information by translating clinical applications to model systems (e.g. measuring cardiac functional metrics) and by pioneering new ones (e.g. measuring tumor vascular permeability with nanoparticle contrast agents). The primary limitations of micro-CT imaging are the associated radiation dose and relatively poor soft tissue contrast. We review several image reconstruction strategies based on iterative, statistical, and gradient sparsity regularization, demonstrating that high image quality is achievable with low radiation dose given ever more powerful computational resources. We also review two contrast mechanisms under intense development. The first is spectral contrast for quantitative material discrimination in combination with passive or actively targeted nanoparticle contrast agents. The second is phase contrast which measures refraction in biological tissues for improved contrast and potentially reduced radiation dose relative to standard absorption imaging. These technological advancements promise to develop micro-CT into a commonplace, functional and even molecular imaging modality. PMID:24974176

Myocardial multilayer strain does not provide additional value for detection of myocardial viability assessed by SPECT imaging over and beyond standard strain.

PubMed

Orloff, Elisabeth; Fournier, Pauline; Bouisset, Frédéric; Moine, Thomas; Cournot, Maxime; Elbaz, Meyer; Carrié, Didier; Galinier, Michel; Lairez, Olivier; Cognet, Thomas

2018-05-14

The aim of this study was to evaluate the value of multilayer strain analysis to the assessment of myocardial viability (MV) through the comparison of both speckle tracking echocardiography and single-photon emission computed tomography (SPECT) imaging. We also intended to determine which segmental longitudinal strain (LS) cutoff value would be optimal to discriminate viable myocardium. We included 47 patients (average age: 61 ± 11 years) referred to our cardiac imaging center for MV evaluation. All patients underwent transthoracic echocardiography with measures of LS, SPECT, and coronary angiography. In all, 799 segments were analyzed. We correlated myocardial tracer uptake by SPECT with sub-endocardial, sub-epicardial, and mid-segmental LS values with r = .514 P < .0001, r = .501 P < .0001, and r = .520 P < .0001, respectively. The measurements of each layer strain (sub-endocardial, sub-epicardial, and mid) had the same performance to predict MV viability as defined by SPECT with areas under curve of 0.819 [0.778-0.861, P < .0001], 0.809 [0.764-0.854, P < .0001], and 0.817 [0.773-0.860, P < .0001], respectively. The receiver-operating characteristic analysis yielded a cutoff value of -6.5% for mid-segmental LS with a sensitivity of 76% and specificity of 76% to predict segmental MV as defined by SPECT. Multilayer strain analysis does not evaluate MV with more accuracy than standard segmental LS analysis. © 2018 Wiley Periodicals, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turkington, T.

This education session will cover the physics and operation principles of gamma cameras and PET scanners. The first talk will focus on PET imaging. An overview of the principles of PET imaging will be provided, including positron decay physics, and the transition from 2D to 3D imaging. More recent advances in hardware and software will be discussed, such as time-of-flight imaging, and improvements in reconstruction algorithms that provide for options such as depth-of-interaction corrections. Quantitative applications of PET will be discussed, as well as the requirements for doing accurate quantitation. Relevant performance tests will also be described. Learning Objectives: Bemore » able to describe basic physics principles of PET and operation of PET scanners. Learn about recent advances in PET scanner hardware technology. Be able to describe advances in reconstruction techniques and improvements Be able to list relevant performance tests. The second talk will focus on gamma cameras. The Nuclear Medicine subcommittee has charged a task group (TG177) to develop a report on the current state of physics testing of gamma cameras, SPECT, and SPECT/CT systems. The report makes recommendations for performance tests to be done for routine quality assurance, annual physics testing, and acceptance tests, and identifies those needed satisfy the ACR accreditation program and The Joint Commission imaging standards. The report is also intended to be used as a manual with detailed instructions on how to perform tests under widely varying conditions. Learning Objectives: At the end of the presentation members of the audience will: Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of gamma cameras for planar imaging. Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of SPECT systems. Be familiar with the tests of a SPECT/CT system that include the CT images for SPECT reconstructions. Become knowledgeable of items to be included in annual acceptance testing reports including CT dosimetry and PACS monitor measurements. T. Turkington, GE Healthcare.« less

Accelerated GPU based SPECT Monte Carlo simulations.

PubMed

Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

2016-06-07

Monte Carlo (MC) modelling is widely used in the field of single photon emission computed tomography (SPECT) as it is a reliable technique to simulate very high quality scans. This technique provides very accurate modelling of the radiation transport and particle interactions in a heterogeneous medium. Various MC codes exist for nuclear medicine imaging simulations. Recently, new strategies exploiting the computing capabilities of graphical processing units (GPU) have been proposed. This work aims at evaluating the accuracy of such GPU implementation strategies in comparison to standard MC codes in the context of SPECT imaging. GATE was considered the reference MC toolkit and used to evaluate the performance of newly developed GPU Geant4-based Monte Carlo simulation (GGEMS) modules for SPECT imaging. Radioisotopes with different photon energies were used with these various CPU and GPU Geant4-based MC codes in order to assess the best strategy for each configuration. Three different isotopes were considered: (99m) Tc, (111)In and (131)I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational efficiency of SPECT imaging simulations.

Dynamic imaging in mild traumatic brain injury: support for the theory of medial temporal vulnerability.

PubMed

Umile, Eric M; Sandel, M Elizabeth; Alavi, Abass; Terry, Charles M; Plotkin, Rosette C

2002-11-01

To determine whether patients with mild traumatic brain injury (TBI) and persistent postconcussive symptoms have evidence of temporal lobe injury on dynamic imaging. Case series. An academic medical center. Twenty patients with a clinical diagnosis of mild TBI and persistent postconcussive symptoms were referred for neuropsychologic evaluation and dynamic imaging. Fifteen (75%) had normal magnetic resonance imaging (MRI) and/or computed tomography (CT) scans at the time of injury. Neuropsychologic testing, positron-emission tomography (PET), and single-photon emission-computed tomography (SPECT). Temporal lobe findings on static imaging (MRI, CT) and dynamic imaging (PET, SPECT); neuropsychologic test findings on measures of verbal and visual memory. Testing documented neurobehavioral deficits in 19 patients (95%). Dynamic imaging documented abnormal findings in 18 patients (90%). Fifteen patients (75%) had temporal lobe abnormalities on PET and SPECT (primarily in medial temporal regions); abnormal findings were bilateral in 10 patients (50%) and unilateral in 5 (25%). Six patients (30%) had frontal abnormalities, and 8 (40%) had nonfrontotemporal abnormalities. Correlations between neuropsychologic testing and dynamic imaging could be established but not consistently across the whole group. Patients with mild TBI and persistent postconcussive symptoms have a high incidence of temporal lobe injury (presumably involving the hippocampus and related structures), which may explain the frequent finding of memory disorders in this population. The abnormal temporal lobe findings on PET and SPECT in humans may be analogous to the neuropathologic evidence of medial temporal injury provided by animal studies after mild TBI. Copyright 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Evaluation of (188)Re-labeled NGR-VEGI protein for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts.

PubMed

Ma, Wenhui; Shao, Yahui; Yang, Weidong; Li, Guiyu; Zhang, Yingqi; Zhang, Mingru; Zuo, Changjing; Chen, Kai; Wang, Jing

2016-07-01

Vascular endothelial growth inhibitor (VEGI) is an anti-angiogenic protein, which includes three isoforms: VEGI-174, VEGI-192, and VEGI-251. The NGR (asparagine-glycine-arginine)-containing peptides can specifically bind to CD13 (Aminopeptidase N) receptor which is overexpressed in angiogenic blood vessels and tumor cells. In this study, a novel NGR-VEGI fusion protein was prepared and labeled with (188)Re for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts. Single photon emission computerized tomography (SPECT) imaging results revealed that (188)Re-NGR-VEGI exhibits good tumor-to-background contrast in CD13-positive HT-1080 tumor xenografts. The CD13 specificity of (188)Re-NGR-VEGI was further verified by significant reduction of tumor uptake in HT-1080 tumor xenografts with co-injection of the non-radiolabeled NGR-VEGI protein. The biodistribution results demonstrated good tumor-to-muscle ratio (4.98 ± 0.25) of (188)Re-NGR-VEGI at 24 h, which is consistent with the results from SPECT imaging. For radiotherapy, 18.5 MBq of (188)Re-NGR-VEGI showed excellent tumor inhibition effect in HT-1080 tumor xenografts with no observable toxicity, which was confirmed by the tumor size change and hematoxylin and eosin (H&E) staining of major mouse organs. In conclusion, these data demonstrated that (188)Re-NGR-VEGI has the potential as a theranostic agent for CD13-targeted tumor imaging and therapy.

LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome.

PubMed

Chen, Chun; Li, Dianfu; Miao, Changqing; Feng, Jianlin; Zhou, Yanli; Cao, Kejiang; Lloyd, Michael S; Chen, Ji

2012-07-01

The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2-3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4%) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p < 0.05). RFA improved LV synchrony in the entire cohort and in the patients with septal APs (p < 0.01). Phase analysis of gated SPECT MPI demonstrated that LV mechanical dyssynchrony can be present in patients with WPW syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI.

Development of a practical image-based scatter correction method for brain perfusion SPECT: comparison with the TEW method.

PubMed

Shidahara, Miho; Watabe, Hiroshi; Kim, Kyeong Min; Kato, Takashi; Kawatsu, Shoji; Kato, Rikio; Yoshimura, Kumiko; Iida, Hidehiro; Ito, Kengo

2005-10-01

An image-based scatter correction (IBSC) method was developed to convert scatter-uncorrected into scatter-corrected SPECT images. The purpose of this study was to validate this method by means of phantom simulations and human studies with 99mTc-labeled tracers, based on comparison with the conventional triple energy window (TEW) method. The IBSC method corrects scatter on the reconstructed image I(mub)AC with Chang's attenuation correction factor. The scatter component image is estimated by convolving I(mub)AC with a scatter function followed by multiplication with an image-based scatter fraction function. The IBSC method was evaluated with Monte Carlo simulations and 99mTc-ethyl cysteinate dimer SPECT human brain perfusion studies obtained from five volunteers. The image counts and contrast of the scatter-corrected images obtained by the IBSC and TEW methods were compared. Using data obtained from the simulations, the image counts and contrast of the scatter-corrected images obtained by the IBSC and TEW methods were found to be nearly identical for both gray and white matter. In human brain images, no significant differences in image contrast were observed between the IBSC and TEW methods. The IBSC method is a simple scatter correction technique feasible for use in clinical routine.

Quantitative cardiac SPECT reconstruction with reduced image degradation due to patient anatomy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsui, B.M.W.; Zhao, X.D.; Gregoriou, G.K.

1994-12-01

Patient anatomy has complicated effects on cardiac SPECT images. The authors investigated reconstruction methods which substantially reduced these effects for improved image quality. A 3D mathematical cardiac-torso (MCAT) phantom which models the anatomical structures in the thorax region were used in the study. The phantom was modified to simulate variations in patient anatomy including regions of natural thinning along the myocardium, body size, diaphragmatic shape, gender, and size and shape of breasts for female patients. Distributions of attenuation coefficients and Tl-201 uptake in different organs in a normal patient were also simulated. Emission projection data were generated from the phantomsmore » including effects of attenuation and detector response. The authors have observed the attenuation-induced artifacts caused by patient anatomy in the conventional FBP reconstructed images. Accurate attenuation compensation using iterative reconstruction algorithms and attenuation maps substantially reduced the image artifacts and improved quantitative accuracy. They conclude that reconstruction methods which accurately compensate for non-uniform attenuation can substantially reduce image degradation caused by variations in patient anatomy in cardiac SPECT.« less

Resting functional imaging tools (MRS, SPECT, PET and PCT).

PubMed

Van Der Naalt, J

2015-01-01

Functional imaging includes imaging techniques that provide information about the metabolic and hemodynamic status of the brain. Most commonly applied functional imaging techniques in patients with traumatic brain injury (TBI) include magnetic resonance spectroscopy (MRS), single photon emission computed tomography (SPECT), positron emission tomography (PET) and perfusion CT (PCT). These imaging modalities are used to determine the extent of injury, to provide information for the prediction of outcome, and to assess evidence of cerebral ischemia. In TBI, secondary brain damage mainly comprises ischemia and is present in more than 80% of fatal cases with traumatic brain injury (Graham et al., 1989; Bouma et al., 1991; Coles et al., 2004). In particular, while SPECT measures cerebral perfusion and MRS determines metabolism, PET is able to assess both perfusion and cerebral metabolism. This chapter will describe the application of these techniques in traumatic brain injury separately for the major groups of severity comprising the mild and moderate to severe group. The application in TBI and potential difficulties of each technique is described. The use of imaging techniques in children will be separately outlined. © 2015 Elsevier B.V. All rights reserved.

The impacts of acute carbon monoxide poisoning on the brain: Longitudinal clinical and 99mTc ethyl cysteinate brain SPECT characterization of patients with persistent and delayed neurological sequelae.

PubMed

Tsai, Chung-Fen; Yip, Ping-Keung; Chen, Shao-Yuan; Lin, Jen-Cheng; Yeh, Zai-Ting; Kung, Lan-Yu; Wang, Cheng-Yi; Fan, Yu-Ming

2014-04-01

Acute carbon monoxide (CO) poisoning poses a significant threat to the central nervous system. It can cause brain injury and diverse neurological deficits including persistent neurological sequelae (PNS) and delayed neurological sequelae (DNS). The study aimed to investigate the long-term impacts of acute CO poisoning on brain perfusion and neurological function, and to explore potential differences between PNS and DNS patients. We evaluated brain perfusion using (99m)Tc ethyl cysteinate (ECD) brain single photon emission computed tomography (SPECT) and assessed clinical neurological symptoms and signs one month following acute poisoning. For DNS patients, ECD SPECT and clinical evaluation were performed when their delayed symptoms appeared. All patients had follow-up SPECT imaging, along with clinical assessments six months following poisoning. 12 PNS and 12 DNS patients were recruited between 2007 and 2010. Clinically, the main characteristic presentations were cognitive decline, emotional instability, and gait disturbance. SPECT imaging demonstrated consistent frontal hypoperfusion of varying severities in all patients, which decreased in severity at follow-up imaging. DNS patients usually had more severe symptoms and perfusion defects, along with worse clinical outcomes than the PNS group. These results suggest that acute CO poisoning might lead to long term brain injuries and neurological sequelae, particularly in DNS patients. Copyright © 2014 Elsevier B.V. All rights reserved.

Image-Guided Drug Delivery with Single-Photon Emission Computed Tomography: A Review of Literature

PubMed Central

Chakravarty, Rubel; Hong, Hao; Cai, Weibo

2014-01-01

Tremendous resources are being invested all over the world for prevention, diagnosis, and treatment of various types of cancer. Successful cancer management depends on accurate diagnosis of the disease along with precise therapeutic protocol. The conventional systemic drug delivery approaches generally cannot completely remove the competent cancer cells without surpassing the toxicity limits to normal tissues. Therefore, development of efficient drug delivery systems holds prime importance in medicine and healthcare. Also, molecular imaging can play an increasingly important and revolutionizing role in disease management. Synergistic use of molecular imaging and targeted drug delivery approaches provides unique opportunities in a relatively new area called `image-guided drug delivery' (IGDD). Single-photon emission computed tomography (SPECT) is the most widely used nuclear imaging modality in clinical context and is increasingly being used to guide targeted therapeutics. The innovations in material science have fueled the development of efficient drug carriers based on, polymers, liposomes, micelles, dendrimers, microparticles, nanoparticles, etc. Efficient utilization of these drug carriers along with SPECT imaging technology have the potential to transform patient care by personalizing therapy to the individual patient, lessening the invasiveness of conventional treatment procedures and rapidly monitoring the therapeutic efficacy. SPECT-IGDD is not only effective for treatment of cancer but might also find utility in management of several other diseases. Herein, we provide a concise overview of the latest advances in SPECT-IGDD procedures and discuss the challenges and opportunities for advancement of the field. PMID:25182469

An Adaptation of the Distance Driven Projection Method for Single Pinhole Collimators in SPECT Imaging

NASA Astrophysics Data System (ADS)

Ihsani, Alvin; Farncombe, Troy

2016-02-01

The modelling of the projection operator in tomographic imaging is of critical importance especially when working with algebraic methods of image reconstruction. This paper proposes a distance-driven projection method which is targeted to single-pinhole single-photon emission computed tomograghy (SPECT) imaging since it accounts for the finite size of the pinhole, and the possible tilting of the detector surface in addition to other collimator-specific factors such as geometric sensitivity. The accuracy and execution time of the proposed method is evaluated by comparing to a ray-driven approach where the pinhole is sub-sampled with various sampling schemes. A point-source phantom whose projections were generated using OpenGATE was first used to compare the resolution of reconstructed images with each method using the full width at half maximum (FWHM). Furthermore, a high-activity Mini Deluxe Phantom (Data Spectrum Corp., Durham, NC, USA) SPECT resolution phantom was scanned using a Gamma Medica X-SPECT system and the signal-to-noise ratio (SNR) and structural similarity of reconstructed images was compared at various projection counts. Based on the reconstructed point-source phantom, the proposed distance-driven approach results in a lower FWHM than the ray-driven approach even when using a smaller detector resolution. Furthermore, based on the Mini Deluxe Phantom, it is shown that the distance-driven approach has consistently higher SNR and structural similarity compared to the ray-driven approach as the counts in measured projections deteriorates.

Area at risk can be assessed by iodine-123-meta-iodobenzylguanidine single-photon emission computed tomography after myocardial infarction: a prospective study.

PubMed

Hedon, Christophe; Huet, Fabien; Ben Bouallegue, Fayçal; Vernhet, Hélène; Macia, Jean-Christophe; Cung, Thien-Tri; Leclercq, Florence; Cade, Stéphane; Cransac, Frédéric; Lattuca, Benoit; Vandenberghe, D'Arcy; Bourdon, Aurélie; Benkiran, Meriem; Vauchot, Fabien; Gervasoni, Richard; D'estanque, Emmanuel; Mariano-Goulart, Denis; Roubille, François

2018-02-01

Myocardial salvage is an important surrogate endpoint to estimate the impact of treatments in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study was to evaluate the correlation between cardiac sympathetic denervation area assessed by single-photon emission computed tomography (SPECT) using iodine-123-meta-iodobenzylguanidine (I-MIBG) and myocardial area at risk (AAR) assessed by cardiac magnetic resonance (CMR) (gold standard). A total of 35 postprimary reperfusion STEMI patients were enrolled prospectively to undergo SPECT using I-MIBG (evaluates cardiac sympathetic denervation) and thallium-201 (evaluates myocardial necrosis), and to undergo CMR imaging using T2-weighted spin-echo turbo inversion recovery for AAR and postgadolinium T1-weighted phase sensitive inversion recovery for scar assessment. I-MIBG imaging showed a wider denervated area (51.1±16.0% of left ventricular area) in comparison with the necrosis area on thallium-201 imaging (16.1±14.4% of left ventricular area, P<0.0001). CMR and SPECT provided similar evaluation of the transmural necrosis (P=0.10) with a good correlation (R=0.86, P<0.0001). AAR on CMR was not different compared with the denervated area (P=0.23) and was adequately correlated (R=0.56, P=0.0002). Myocardial salvage evaluated by SPECT imaging (mismatch denervated but viable myocardium) was significantly higher than by CMR (P=0.02). In patients with STEMI, I-MIBG SPECT, assessing cardiac sympathetic denervation may precisely evaluate the AAR, providing an alternative to CMR for AAR assessment.

Correlation between 99Tcm-HMPAO-SPECT brain image and a history of decompression illness or extent of diving experience in commercial divers.

PubMed Central

Shields, T G; Duff, P M; Evans, S A; Gemmell, H G; Sharp, P F; Smith, F W; Staff, R T; Wilcock, S E

1997-01-01

OBJECTIVES: To explore the use of 99technetiumm-hexamethyl propylene amine oxime single photon computed tomography (HMPAO-SPECT) of the brain as a means of detecting nervous tissue damage in divers and to determine if there is any correlation between brain image and a diver's history of diving or decompression illness (DCI). METHODS: 28 commercial divers with a history of DCI, 26 divers with no history of DCI, and 19 non-diving controls were examined with brain HMPAO-SPECT. Results were classified by observer assessment as normal (I) or as a pattern variants (II-V). The brain images of a subgroup of these divers (n = 44) and the controls (n = 17) were further analysed with a first order texture analysis technique based on a grey level histogram. RESULTS: 15 of 54 commercial divers (28%) were visually assessed as having HMPAO-SPECT images outside normal limits compared with 15.8% in appropriately identified non-diver control subjects. 18% of divers with a history of DCI were classified as having a pattern different from the normal image compared with 38% with no history of DCI. No association was established between the presence of a pattern variant from the normal image and history of DCI, diving, or other previous possible neurological insult. On texture analysis of the brain images, divers had a significantly lower mean grey level (MGL) than non-divers. Divers with a history of DCI (n = 22) had a significantly lower MGL when compared with divers with no history of DCI (n = 22). Divers with > 14 years professional diving or > 100 decompression days a year had a significantly lower MGL value. CONCLUSIONS: Observer assessment of HMPAO-SPECT brain images can lead to disparity in results. Texture analysis of the brain images supplies both an objective and consistent method of measurement. A significant correlation was found between a low measure of MGL and a history of DCI. There was also an indication that diving itself had an effect on texture measurement, implying that it had caused subclinical nervous tissue damage. PMID:9166130

Task-based design of a synthetic-collimator SPECT system used for small animal imaging.

PubMed

Lin, Alexander; Kupinski, Matthew A; Peterson, Todd E; Shokouhi, Sepideh; Johnson, Lindsay C

2018-05-07

In traditional multipinhole SPECT systems, image multiplexing - the overlapping of pinhole projection images - may occur on the detector, which can inhibit quality image reconstructions due to photon-origin uncertainty. One proposed system to mitigate the effects of multiplexing is the synthetic-collimator SPECT system. In this system, two detectors, a silicon detector and a germanium detector, are placed at different distances behind the multipinhole aperture, allowing for image detection to occur at different magnifications and photon energies, resulting in higher overall sensitivity while maintaining high resolution. The unwanted effects of multiplexing are reduced by utilizing the additional data collected from the front silicon detector. However, determining optimal system configurations for a given imaging task requires efficient parsing of the complex parameter space, to understand how pinhole spacings and the two detector distances influence system performance. In our simulation studies, we use the ensemble mean-squared error of the Wiener estimator (EMSE W ) as the figure of merit to determine optimum system parameters for the task of estimating the uptake of an 123 I-labeled radiotracer in three different regions of a computer-generated mouse brain phantom. The segmented phantom map is constructed by using data from the MRM NeAt database and allows for the reduction in dimensionality of the system matrix which improves the computational efficiency of scanning the system's parameter space. To contextualize our results, the Wiener estimator is also compared against a region of interest estimator using maximum-likelihood reconstructed data. Our results show that the synthetic-collimator SPECT system outperforms traditional multipinhole SPECT systems in this estimation task. We also find that image multiplexing plays an important role in the system design of the synthetic-collimator SPECT system, with optimal germanium detector distances occurring at maxima in the derivative of the percent multiplexing function. Furthermore, we report that improved task performance can be achieved by using an adaptive system design in which the germanium detector distance may vary with projection angle. Finally, in our comparative study, we find that the Wiener estimator outperforms the conventional region of interest estimator. Our work demonstrates how this optimization method has the potential to quickly and efficiently explore vast parameter spaces, providing insight into the behavior of competing factors, which are otherwise very difficult to calculate and study using other existing means. © 2018 American Association of Physicists in Medicine.

An introduction to Na(18)F bone scintigraphy: basic principles, advanced imaging concepts, and case examples.

PubMed

Bridges, Robert L; Wiley, Chris R; Christian, John C; Strohm, Adam P

2007-06-01

Na(18)F, an early bone scintigraphy agent, is poised to reenter mainstream clinical imaging with the present generations of stand-alone PET and PET/CT hybrid scanners. (18)F PET scans promise improved imaging quality for both benign and malignant bone disease, with significantly improved sensitivity and specificity over conventional planar and SPECT bone scans. In this article, basic acquisition information will be presented along with examples of studies related to oncology, sports medicine, and general orthopedics. The use of image fusion of PET bone scans with CT and MRI will be demonstrated. The objectives of this article are to provide the reader with an understanding of the history of early bone scintigraphy in relation to Na(18)F scanning, a familiarity with basic imaging techniques for PET bone scanning, an appreciation of the extent of disease processes that can be imaged with PET bone scanning, an appreciation for the added value of multimodality image fusion with bone disease, and a recognition of the potential role PET bone scanning may play in clinical imaging.

Automated MicroSPECT/MicroCT Image Analysis of the Mouse Thyroid Gland.

PubMed

Cheng, Peng; Hollingsworth, Brynn; Scarberry, Daniel; Shen, Daniel H; Powell, Kimerly; Smart, Sean C; Beech, John; Sheng, Xiaochao; Kirschner, Lawrence S; Menq, Chia-Hsiang; Jhiang, Sissy M

2017-11-01

The ability of thyroid follicular cells to take up iodine enables the use of radioactive iodine (RAI) for imaging and targeted killing of RAI-avid thyroid cancer following thyroidectomy. To facilitate identifying novel strategies to improve 131 I therapeutic efficacy for patients with RAI refractory disease, it is desired to optimize image acquisition and analysis for preclinical mouse models of thyroid cancer. A customized mouse cradle was designed and used for microSPECT/CT image acquisition at 1 hour (t1) and 24 hours (t24) post injection of 123 I, which mainly reflect RAI influx/efflux equilibrium and RAI retention in the thyroid, respectively. FVB/N mice with normal thyroid glands and TgBRAF V600E mice with thyroid tumors were imaged. In-house CTViewer software was developed to streamline image analysis with new capabilities, along with display of 3D voxel-based 123 I gamma photon intensity in MATLAB. The customized mouse cradle facilitates consistent tissue configuration among image acquisitions such that rigid body registration can be applied to align serial images of the same mouse via the in-house CTViewer software. CTViewer is designed specifically to streamline SPECT/CT image analysis with functions tailored to quantify thyroid radioiodine uptake. Automatic segmentation of thyroid volumes of interest (VOI) from adjacent salivary glands in t1 images is enabled by superimposing the thyroid VOI from the t24 image onto the corresponding aligned t1 image. The extent of heterogeneity in 123 I accumulation within thyroid VOIs can be visualized by 3D display of voxel-based 123 I gamma photon intensity. MicroSPECT/CT image acquisition and analysis for thyroidal RAI uptake is greatly improved by the cradle and the CTViewer software, respectively. Furthermore, the approach of superimposing thyroid VOIs from t24 images to select thyroid VOIs on corresponding aligned t1 images can be applied to studies in which the target tissue has differential radiotracer retention from surrounding tissues.

Performance evaluation of a novel high performance pinhole array detector module using NEMA NU-4 image quality phantom for four head SPECT Imaging

NASA Astrophysics Data System (ADS)

Rahman, Tasneem; Tahtali, Murat; Pickering, Mark R.

2015-03-01

Radiolabeled tracer distribution imaging of gamma rays using pinhole collimation is considered promising for small animal imaging. The recent availability of various radiolabeled tracers has enhanced the field of diagnostic study and is simultaneously creating demand for high resolution imaging devices. This paper presents analyses to represent the optimized parameters of a high performance pinhole array detector module using two different characteristics phantoms. Monte Carlo simulations using the Geant4 application for tomographic emission (GATE) were executed to assess the performance of a four head SPECT system incorporated with pinhole array collimators. The system is based on a pixelated array of NaI(Tl) crystals coupled to an array of position sensitive photomultiplier tubes (PSPMTs). The detector module was simulated to have 48 mm by 48 mm active area along with different pinhole apertures on a tungsten plate. The performance of this system has been evaluated using a uniform shape cylindrical water phantom along with NEMA NU-4 image quality (IQ) phantom filled with 99mTc labeled radiotracers. SPECT images were reconstructed where activity distribution is expected to be well visualized. This system offers the combination of an excellent intrinsic spatial resolution, good sensitivity and signal-to-noise ratio along with high detection efficiency over an energy range between 20-160 keV. Increasing number of heads in a stationary system configuration offers increased sensitivity at a spatial resolution similar to that obtained with the current SPECT system design with four heads.

SU-E-I-23: Design and Clinical Application of External Marking Body in Multi- Mode Medical Images Registration and Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Z; Gong, G

2014-06-01

Purpose: To design an external marking body (EMB) that could be visible on computed tomography (CT), magnetic resonance (MR), positron emission tomography (PET) and single-photon emission computed tomography (SPECT) images and to investigate the use of the EMB for multiple medical images registration and fusion in the clinic. Methods: We generated a solution containing paramagnetic metal ions and iodide ions (CT'MR dual-visible solution) that could be viewed on CT and MR images and multi-mode image visible solution (MIVS) that could be obtained by mixing radioactive nuclear material. A globular plastic theca (diameter: 3–6 mm) that mothball the MIVS and themore » EMB was brought by filling MIVS. The EMBs were fixed on the patient surface and CT, MR, PET and SPECT scans were obtained. The feasibility of clinical application and the display and registration error of EMB among different image modalities were investigated. Results: The dual-visible solution was highly dense on CT images (HU>700). A high signal was also found in all MR scanning (T1, T2, STIR and FLAIR) images, and the signal was higher than subcutaneous fat. EMB with radioactive nuclear material caused a radionuclide concentration area on PET and SPECT images, and the signal of EMB was similar to or higher than tumor signals. The theca with MIVS was clearly visible on all the images without artifact, and the shape was round or oval with a sharp edge. The maximum diameter display error was 0.3 ± 0.2mm on CT and MRI images, and 1.0 ± 0.3mm on PET and SPECT images. In addition, the registration accuracy of the theca center among multi-mode images was less than 1mm. Conclusion: The application of EMB with MIVS improves the registration and fusion accuracy of multi-mode medical images. Furthermore, it has the potential to ameliorate disease diagnosis and treatment outcome.« less

New cardiac cameras: single-photon emission CT and PET.

PubMed

Slomka, Piotr J; Berman, Daniel S; Germano, Guido

2014-07-01

Nuclear cardiology instrumentation has evolved significantly in the recent years. Concerns about radiation dose and long acquisition times have propelled developments of dedicated high-efficiency cardiac SPECT scanners. Novel collimator designs, such as multipinhole or locally focusing collimators arranged in geometries that are optimized for cardiac imaging, have been implemented to enhance photon-detection sensitivity. Some of these new SPECT scanners use solid-state photon detectors instead of photomultipliers to improve image quality and to reduce the scanner footprint. These new SPECT devices allow dramatic up to 7-fold reduction in acquisition times or similar reduction in radiation dose. In addition, new hardware for photon attenuation correction allowing ultralow radiation doses has been offered by some vendors. To mitigate photon attenuation artifacts for the new SPECT scanners not equipped with attenuation correction hardware, 2-position (upright-supine or prone-supine) imaging has been proposed. PET hardware developments have been primarily driven by the requirements of oncologic imaging, but cardiac imaging can benefit from improved PET image quality and improved sensitivity of 3D systems. The time-of-flight reconstruction combined with resolution recovery techniques is now implemented by all major PET vendors. These new methods improve image contrast and image resolution and reduce image noise. High-sensitivity 3D PET without interplane septa allows reduced radiation dose for cardiac perfusion imaging. Simultaneous PET/MR hybrid system has been developed. Solid-state PET detectors with avalanche photodiodes or digital silicon photomultipliers have been introduced, and they offer improved imaging characteristics and reduced sensitivity to electromagnetic MR fields. Higher maximum count rate of the new PET detectors allows routine first-pass Rb-82 imaging, with 3D PET acquisition enabling clinical utilization of dynamic imaging with myocardial flow measurements for this tracer. The availability of high-end CT component in most PET/CT configurations enables hybrid multimodality cardiac imaging protocols with calcium scoring or CT angiography or both. Copyright © 2014. Published by Elsevier Inc.

Comparison of quantitative Y-90 SPECT and non-time-of-flight PET imaging in post-therapy radioembolization of liver cancer

PubMed Central

Yue, Jianting; Mauxion, Thibault; Reyes, Diane K.; Lodge, Martin A.; Hobbs, Robert F.; Rong, Xing; Dong, Yinfeng; Herman, Joseph M.; Wahl, Richard L.; Geschwind, Jean-François H.; Frey, Eric C.

2016-01-01

Purpose: Radioembolization with yttrium-90 microspheres may be optimized with patient-specific pretherapy treatment planning. Dose verification and validation of treatment planning methods require quantitative imaging of the post-therapy distribution of yttrium-90 (Y-90). Methods for quantitative imaging of Y-90 using both bremsstrahlung SPECT and PET have previously been described. The purpose of this study was to compare the two modalities quantitatively in humans. Methods: Calibration correction factors for both quantitative Y-90 bremsstrahlung SPECT and a non-time-of-flight PET system without compensation for prompt coincidences were developed by imaging three phantoms. The consistency of these calibration correction factors for the different phantoms was evaluated. Post-therapy images from both modalities were obtained from 15 patients with hepatocellular carcinoma who underwent hepatic radioembolization using Y-90 glass microspheres. Quantitative SPECT and PET images were rigidly registered and the total liver activities and activity distributions estimated for each modality were compared. The activity distributions were compared using profiles, voxel-by-voxel correlation and Bland–Altman analyses, and activity-volume histograms. Results: The mean ± standard deviation of difference in the total activity in the liver between the two modalities was 0% ± 9% (range −21%–18%). Voxel-by-voxel comparisons showed a good agreement in regions corresponding roughly to treated tumor and treated normal liver; the agreement was poorer in regions with low or no expected activity, where PET appeared to overestimate the activity. The correlation coefficients between intrahepatic voxel pairs for the two modalities ranged from 0.86 to 0.94. Cumulative activity volume histograms were in good agreement. Conclusions: These data indicate that, with appropriate reconstruction methods and measured calibration correction factors, either Y-90 SPECT/CT or Y-90 PET/CT can be used for quantitative post-therapy monitoring of Y-90 activity distribution following hepatic radioembolization. PMID:27782730

Dynamic single photon emission computed tomography—basic principles and cardiac applications

PubMed Central

Gullberg, Grant T; Reutter, Bryan W; Sitek, Arkadiusz; Maltz, Jonathan S; Budinger, Thomas F

2011-01-01

The very nature of nuclear medicine, the visual representation of injected radiopharmaceuticals, implies imaging of dynamic processes such as the uptake and wash-out of radiotracers from body organs. For years, nuclear medicine has been touted as the modality of choice for evaluating function in health and disease. This evaluation is greatly enhanced using single photon emission computed tomography (SPECT), which permits three-dimensional (3D) visualization of tracer distributions in the body. However, to fully realize the potential of the technique requires the imaging of in vivo dynamic processes of flow and metabolism. Tissue motion and deformation must also be addressed. Absolute quantification of these dynamic processes in the body has the potential to improve diagnosis. This paper presents a review of advancements toward the realization of the potential of dynamic SPECT imaging and a brief history of the development of the instrumentation. A major portion of the paper is devoted to the review of special data processing methods that have been developed for extracting kinetics from dynamic cardiac SPECT data acquired using rotating detector heads that move as radiopharmaceuticals exchange between biological compartments. Recent developments in multi-resolution spatiotemporal methods enable one to estimate kinetic parameters of compartment models of dynamic processes using data acquired from a single camera head with slow gantry rotation. The estimation of kinetic parameters directly from projection measurements improves bias and variance over the conventional method of first reconstructing 3D dynamic images, generating time–activity curves from selected regions of interest and then estimating the kinetic parameters from the generated time–activity curves. Although the potential applications of SPECT for imaging dynamic processes have not been fully realized in the clinic, it is hoped that this review illuminates the potential of SPECT for dynamic imaging, especially in light of new developments that enable measurement of dynamic processes directly from projection measurements. PMID:20858925

Comparison of quantitative Y-90 SPECT and non-time-of-flight PET imaging in post-therapy radioembolization of liver cancer.

PubMed

Yue, Jianting; Mauxion, Thibault; Reyes, Diane K; Lodge, Martin A; Hobbs, Robert F; Rong, Xing; Dong, Yinfeng; Herman, Joseph M; Wahl, Richard L; Geschwind, Jean-François H; Frey, Eric C

2016-10-01

Radioembolization with yttrium-90 microspheres may be optimized with patient-specific pretherapy treatment planning. Dose verification and validation of treatment planning methods require quantitative imaging of the post-therapy distribution of yttrium-90 (Y-90). Methods for quantitative imaging of Y-90 using both bremsstrahlung SPECT and PET have previously been described. The purpose of this study was to compare the two modalities quantitatively in humans. Calibration correction factors for both quantitative Y-90 bremsstrahlung SPECT and a non-time-of-flight PET system without compensation for prompt coincidences were developed by imaging three phantoms. The consistency of these calibration correction factors for the different phantoms was evaluated. Post-therapy images from both modalities were obtained from 15 patients with hepatocellular carcinoma who underwent hepatic radioembolization using Y-90 glass microspheres. Quantitative SPECT and PET images were rigidly registered and the total liver activities and activity distributions estimated for each modality were compared. The activity distributions were compared using profiles, voxel-by-voxel correlation and Bland-Altman analyses, and activity-volume histograms. The mean ± standard deviation of difference in the total activity in the liver between the two modalities was 0% ± 9% (range -21%-18%). Voxel-by-voxel comparisons showed a good agreement in regions corresponding roughly to treated tumor and treated normal liver; the agreement was poorer in regions with low or no expected activity, where PET appeared to overestimate the activity. The correlation coefficients between intrahepatic voxel pairs for the two modalities ranged from 0.86 to 0.94. Cumulative activity volume histograms were in good agreement. These data indicate that, with appropriate reconstruction methods and measured calibration correction factors, either Y-90 SPECT/CT or Y-90 PET/CT can be used for quantitative post-therapy monitoring of Y-90 activity distribution following hepatic radioembolization.

TOPICAL REVIEW: Dynamic single photon emission computed tomography—basic principles and cardiac applications

NASA Astrophysics Data System (ADS)

Gullberg, Grant T.; Reutter, Bryan W.; Sitek, Arkadiusz; Maltz, Jonathan S.; Budinger, Thomas F.

2010-10-01

The very nature of nuclear medicine, the visual representation of injected radiopharmaceuticals, implies imaging of dynamic processes such as the uptake and wash-out of radiotracers from body organs. For years, nuclear medicine has been touted as the modality of choice for evaluating function in health and disease. This evaluation is greatly enhanced using single photon emission computed tomography (SPECT), which permits three-dimensional (3D) visualization of tracer distributions in the body. However, to fully realize the potential of the technique requires the imaging of in vivo dynamic processes of flow and metabolism. Tissue motion and deformation must also be addressed. Absolute quantification of these dynamic processes in the body has the potential to improve diagnosis. This paper presents a review of advancements toward the realization of the potential of dynamic SPECT imaging and a brief history of the development of the instrumentation. A major portion of the paper is devoted to the review of special data processing methods that have been developed for extracting kinetics from dynamic cardiac SPECT data acquired using rotating detector heads that move as radiopharmaceuticals exchange between biological compartments. Recent developments in multi-resolution spatiotemporal methods enable one to estimate kinetic parameters of compartment models of dynamic processes using data acquired from a single camera head with slow gantry rotation. The estimation of kinetic parameters directly from projection measurements improves bias and variance over the conventional method of first reconstructing 3D dynamic images, generating time-activity curves from selected regions of interest and then estimating the kinetic parameters from the generated time-activity curves. Although the potential applications of SPECT for imaging dynamic processes have not been fully realized in the clinic, it is hoped that this review illuminates the potential of SPECT for dynamic imaging, especially in light of new developments that enable measurement of dynamic processes directly from projection measurements.

[Image fusion of gated-SPECT and CT angiography in coronary artery disease. Importance of anatomic-functional correlation].

PubMed

Nazarena Pizzi, M; Aguadé Bruix, S; Cuéllar Calabria, H; Aliaga, V; Candell Riera, J

2010-01-01

A 77-year old patient was admitted for acute coronary syndrome without ST elevation. His risk was stratified using the myocardial perfusion gated SPECT, mild inferior ischemia being observed. Thus, medical therapy was optimized and the patient was discharged. He continued with exertional dyspnea so a coronary CT angiography was performed. It revealed severe lesions in the proximal RCA. SPECT-CT fusion images correlated the myocardial perfusion defect with a posterior descending artery from the RCA, in a co-dominant coronary area. Subsequently, cardiac catheterism was indicated for his treatment. The current use of image fusion studies is limited to patients in whom it is difficult to attribute a perfusion defect to a specific coronary artery. In our patient, the fusion images helped to distinguish between the RCA and the circumflex artery as the culprit artery of ischemia. Copyright © 2010 Elsevier España, S.L. y SEMNIM. All rights reserved.

Longitudinal Evaluation of Fatty Acid Metabolism in Normal and Spontaneously Hypertensive Rat Hearts with Dynamic MicroSPECT Imaging

DOE PAGES

Reutter, Bryan W.; Huesman, Ronald H.; Brennan, Kathleen M.; ...

2011-01-01

The goal of this project is to develop radionuclide molecular imaging technologies using a clinical pinhole SPECT/CT scanner to quantify changes in cardiac metabolism using the spontaneously hypertensive rat (SHR) as a model of hypertensive-related pathophysiology. This paper quantitatively compares fatty acid metabolism in hearts of SHR and Wistar-Kyoto normal rats as a function of age and thereby tracks physiological changes associated with the onset and progression of heart failure in the SHR model. The fatty acid analog, 123 I-labeled BMIPP, was used in longitudinal metabolic pinhole SPECT imaging studies performed every seven months for 21 months. The uniqueness ofmore » this project is the development of techniques for estimating the blood input function from projection data acquired by a slowly rotating camera that is imaging fast circulation and the quantification of the kinetics of 123 I-BMIPP by fitting compartmental models to the blood and tissue time-activity curves.« less

Diagnostic value of thallium-201 myocardial perfusion IQ-SPECT without and with computed tomography-based attenuation correction to predict clinically significant and insignificant fractional flow reserve

PubMed Central

Tanaka, Haruki; Takahashi, Teruyuki; Ohashi, Norihiko; Tanaka, Koichi; Okada, Takenori; Kihara, Yasuki

2017-01-01

Abstract The aim of this study was to clarify the predictive value of fractional flow reserve (FFR) determined by myocardial perfusion imaging (MPI) using thallium (Tl)-201 IQ-SPECT without and with computed tomography-based attenuation correction (CT-AC) for patients with stable coronary artery disease (CAD). We assessed 212 angiographically identified diseased vessels using adenosine-stress Tl-201 MPI-IQ-SPECT/CT in 84 consecutive, prospectively identified patients with stable CAD. We compared the FFR in 136 of the 212 diseased vessels using visual semiquantitative interpretations of corresponding territories on MPI-IQ-SPECT images without and with CT-AC. FFR inversely correlated most accurately with regional summed difference scores (rSDS) in images without and with CT-AC (r = −0.584 and r = −0.568, respectively, both P < .001). Receiver-operating characteristics analyses using rSDS revealed an optimal FFR cut-off of <0.80 without and with CT-AC. Although the diagnostic accuracy of FFR <0.80 did not significantly differ, FFR ≥0.82 was significantly more accurate with, than without CT-AC. Regions with rSDS ≥2 without or with CT-AC predicted FFR <0.80, and those with rSDS ≤1 without and with CT-AC predicted FFR ≥0.81, with 73% and 83% sensitivity, 84% and 67% specificity, and 79% and 75% accuracy, respectively. Although limited by the sample size and the single-center design, these findings showed that the IQ-SPECT system can predict FFR at an optimal cut-off of <0.80, and we propose a novel application of CT-AC to MPI-IQ-SPECT for predicting clinically significant and insignificant FFR even in nonobese patients. PMID:29390486

Myocardial Uptake of 7′-(Z)-[123I]Iodorotenone During Vasodilator Stress in Dogs With Critical Coronary Stenoses

PubMed Central

Broisat, Alexis; Ruiz, Mirta; Goodman, Norman C.; Hanrahan, Stephen M.; Reutter, Bryan W.; Brennan, Kathleen M.; Janabi, Mustafa; Schaefer, Saul; Watson, Denny D.; Beller, George A.; VanBrocklin, Henry F.; Glover, David K.

2013-01-01

Background There is a well-recognized need for a new generation of single photon emission computed tomography (SPECT) perfusion tracers with improved myocardial extraction over a wide flow range. Radiotracers that target complex I of the mitochondrial electron transport chain have been proposed as a new class of myocardial perfusion imaging agents. 7-(Z)-[125I]iodorotenone (125I-ZIROT) has demonstrated superior myocardial extraction and retention characteristics in rats and in isolated perfused rabbit hearts. We sought to fully characterize the biodistribution and myocardial extraction versus flow relationship of 123I-ZIROT in an intact large-animal model. Methods and Results The 123I-ZIROT was administered during adenosine A2A agonist-induced hyperemia in 5 anesthetized dogs with critical left anterior descending (LAD) stenoses. When left circumflex (LCx) flow was maximal, 123I-ZIROT and microspheres were coinjected and the dogs were euthanized 5 minutes later. 123I-ZIROT biodistribution was evaluated in 2 additional dogs by in vivo planar imaging. At 123I-ZIROT injection, transmural LAD flow was unchanged from baseline (mean±SEM, 0.90±0.22 versus 0.87±0.11 mL/[min · g]; P=0.92), whereas LCx zone flow increased significantly (mean±SEM, 3.25±0.51 versus 1.00±0.17 mL/[min · g]; P<0.05). Myocardial 123I-ZIROT extraction tracked regional myocardial flow better than either thallium-201 or 99mTc-sestamibi from previous studies using a similar model. Furthermore, the 123I-ZIROT LAD/LCx activity ratios by ex vivo imaging or well counting (mean±SEM, 0.42±0.08 and 0.45±0.1, respectively) only slightly underestimated the LAD/LCx microsphere flow ratio (0.32±0.09). Conclusions The ability of 123I-ZIROT to more linearly track blood flow over a wide range makes it a promising new SPECT myocardial perfusion imaging agent with potential for improved coronary artery disease detection and better quantitative estimation of the severity of flow impairment. PMID:21917783

SPECT and PET in ischemic heart failure.

PubMed

Angelidis, George; Giamouzis, Gregory; Karagiannis, Georgios; Butler, Javed; Tsougos, Ioannis; Valotassiou, Varvara; Giannakoulas, George; Dimakopoulos, Nikolaos; Xanthopoulos, Andrew; Skoularigis, John; Triposkiadis, Filippos; Georgoulias, Panagiotis

2017-03-01

Heart failure is a common clinical syndrome associated with significant morbidity and mortality worldwide. Ischemic heart disease is the leading cause of heart failure, at least in the industrialized countries. Proper diagnosis of the syndrome and management of patients with heart failure require anatomical and functional information obtained through various imaging modalities. Nuclear cardiology techniques play a main role in the evaluation of heart failure. Myocardial single photon emission computed tomography (SPECT) with thallium-201 or technetium-99 m labelled tracers offer valuable data regarding ventricular function, myocardial perfusion, viability, and intraventricular synchronism. Moreover, positron emission tomography (PET) permits accurate evaluation of myocardial perfusion, metabolism, and viability, providing high-quality images and the ability of quantitative analysis. As these imaging techniques assess different parameters of cardiac structure and function, variations of sensitivity and specificity have been reported among them. In addition, the role of SPECT and PET guided therapy remains controversial. In this comprehensive review, we address these controversies and report the advances in patient's investigation with SPECT and PET in ischemic heart failure. Furthermore, we present the innovations in technology that are expected to strengthen the role of nuclear cardiology modalities in the investigation of heart failure.

Left ventricular functional parameters by gated SPECT myocardial perfusion imaging in a Latin American country.

PubMed

Kapitan, Miguel; Beltran, Alvaro; Beretta, Mario; Mut, Fernando

2018-04-01

There is paucity of data on left ventricular (LV) functional parameters using gated SPECT myocardial perfusion imaging (MPI) from the Latin American region. This study provides detailed information in low-risk patients both at rest and during exercise. We studied 90 patients (50 men) with a very low likelihood of coronary artery disease. Gated-SPECT MPI was performed with Tc-99m MIBI using a 2-day protocol, with 16 frames/R-R cycle. The LV ejection fraction and volumes were not different between the rest and post-stress images. LVEF was 68 ± 7% post-stress and 70 ± 7% at rest in women, and 62 ± 7% and 63 ± 7%, respectively, in men (P = .19, .26). LV volumes were larger in men than women (P < .01). There were no differences in most variables obtained at rest or post-stress. Transient ischemic dilatation was similar, with upper limits of 1.20 and 1.19 in women and men, respectively (P = NS). These data could prove helpful for the interpretation of gated SPECT MPI data in Latin America using identical protocol as used in this study.

A Monte Carlo study on the performance evaluation of a parallel hole collimator for a HiReSPECT: A dedicated small-animal SPECT.

PubMed

Abbaspour, Samira; Tanha, Kaveh; Mahmoudian, Babak; Assadi, Majid; Pirayesh Islamian, Jalil

2018-04-22

Collimator geometry has an important contribution on the image quality in SPECT imaging. The purpose of this study was to investigate the effect of parallel hole collimator hole-size on the functional parameters (including the spatial resolution and sensitivity) and the image quality of a HiReSPECT imaging system using SIMIND Monte Carlo program. To find a proper trade-off between the sensitivity and spatial resolution, the collimator with hole diameter ranges of 0.3-1.5 mm (in steps of 0.3 mm) were used with a fixed septal and hole thickness values (0.2 mm and 34 mm, respectively). Lead, Gold, and Tungsten as the LEHR collimator material were also investigated. The results on a 99m Tc point source scanning with the experimental and also simulated systems were matched to validate the simulated imaging system. The results on the simulation showed that decreasing the collimator hole size, especially in the Gold collimator, improved the spatial resolution to 18% and 3.2% compared to the Lead and the Tungsten, respectively. Meanwhile, the Lead collimator provided a good sensitivity in about of 7% and 8% better than that of Tungsten and Gold, respectively. Overall, the spatial resolution and sensitivity showed small differences among the three types of collimator materials assayed within the defined energy. By increasing the hole size, the Gold collimator produced lower scatter and penetration fractions than Tungsten and Lead collimator. The minimum detectable size of hot rods in micro-Jaszczak phantom on the iterative maximum-likelihood expectation maximization (MLEM) reconstructed images, were determined in the sectors of 1.6, 1.8, 2.0, 2.4 and 2.6 mm for scanning with the collimators in hole sizes of 0.3, 0.6, 0.9, 1.2 and 1.5 mm at a 5 cm distance from the phantom. The Gold collimator with hole size of 0.3 mm provided a better image quality with the HiReSPECT imaging. Copyright © 2018 Elsevier Ltd. All rights reserved.

SPECT brain perfusion abnormalities in mild or moderate traumatic brain injury.

PubMed

Abdel-Dayem, H M; Abu-Judeh, H; Kumar, M; Atay, S; Naddaf, S; El-Zeftawy, H; Luo, J Q

1998-05-01

The purpose of this atlas is to present a review of the literature showing the advantages of SPECT brain perfusion imaging (BPI) in mild or moderate traumatic brain injury (TBI) over other morphologic imaging modalities such as x-ray CT or MRI. The authors also present the technical recommendations for SPECT brain perfusion currently practiced at their center. For the radiopharmaceutical of choice, a comparison between early and delayed images using Tc-99m HMPAO and Tc-99m ECD showed that Tc-99m HMPAO is more stable in the brain with no washout over time. Therefore, the authors feel that Tc-99m HMPAO is preferable to Tc-99m ECD. Recommendations regarding standardizing intravenous injection, the acquisition, processing parameters, and interpretation of scans using a ten grade color scale, and use of the cerebellum as the reference organ are presented. SPECT images of 228 patients (age range, 11 to 88; mean, 40.8 years) with mild or moderate TBI and no significant medical history that interfered with the results of the SPECT BP were reviewed. The etiology of the trauma was in the following order of frequency: motor vehicle accidents (45%) followed by blow to the head (36%) and a fall (19%). Frequency of the symptoms was headache (60.9%), memory problems (27.6%), dizziness (26.7%), and sleep disorders (8.7%). Comparison between patients imaged early (<3 months) versus those imaged delayed (>3 months) from the time of the accident, showed that early imaging detected more lesions (4.2 abnormal lesions per study compared to 2.7 in those imaged more than 3 months after the accident). Of 41 patients who had mild traumatic injury without loss of consciousness and had normal CT, 28 studies were abnormal. Focal areas of hypoperfusion were seen in 77% (176 patients, 612 lesions) of the group of 228 patients. The sites of abnormalities were in the following order: basal ganglia and thalami, 55.2%, frontal lobes, 23.8%, temporal lobes, 13%, parietal, 3.7%, insular and occipital lobes together, 4.6%.

Reliability evaluation of I-123 ADAM SPECT imaging using SPM software and AAL ROI methods

NASA Astrophysics Data System (ADS)

Yang, Bang-Hung; Tsai, Sung-Yi; Wang, Shyh-Jen; Su, Tung-Ping; Chou, Yuan-Hwa; Chen, Chia-Chieh; Chen, Jyh-Cheng

2011-08-01

The level of serotonin was regulated by serotonin transporter (SERT), which is a decisive protein in regulation of serotonin neurotransmission system. Many psychiatric disorders and therapies were also related to concentration of cerebral serotonin. I-123 ADAM was the novel radiopharmaceutical to image SERT in brain. The aim of this study was to measure reliability of SERT densities of healthy volunteers by automated anatomical labeling (AAL) method. Furthermore, we also used statistic parametric mapping (SPM) on a voxel by voxel analysis to find difference of cortex between test and retest of I-123 ADAM single photon emission computed tomography (SPECT) images.Twenty-one healthy volunteers were scanned twice with SPECT at 4 h after intravenous administration of 185 MBq of 123I-ADAM. The image matrix size was 128×128 and pixel size was 3.9 mm. All images were obtained through filtered back-projection (FBP) reconstruction algorithm. Region of interest (ROI) definition was performed based on the AAL brain template in PMOD version 2.95 software package. ROI demarcations were placed on midbrain, pons, striatum, and cerebellum. All images were spatially normalized to the SPECT MNI (Montreal Neurological Institute) templates supplied with SPM2. And each image was transformed into standard stereotactic space, which was matched to the Talairach and Tournoux atlas. Then differences across scans were statistically estimated on a voxel by voxel analysis using paired t-test (population main effect: 2 cond's, 1 scan/cond.), which was applied to compare concentration of SERT between the test and retest cerebral scans.The average of specific uptake ratio (SUR: target/cerebellum-1) of 123I-ADAM binding to SERT in midbrain was 1.78±0.27, pons was 1.21±0.53, and striatum was 0.79±0.13. The cronbach's α of intra-class correlation coefficient (ICC) was 0.92. Besides, there was also no significant statistical finding in cerebral area using SPM2 analysis. This finding might help us to understand reliability of I-123 ADAM SPECT imaging and further develop new strategy for the treatment of psychiatric disorders.

[Study of dopamine transporter imaging on the brain of children with autism].

PubMed

Sun, Xiaomian; Yue, Jing; Zheng, Chongxun

2008-04-01

This study was conducted to evaluate the applicability of 99mTc-2beta-[ N, N'-bis (2-mercaptoethyl) ethylenediamino]methyl,3beta(4-chlorophenyl)tropane(TRODAT-1) dopamine transporter(DAT) SPECT imaging in children with autism, and thus to provide an academic basis for the etiology, mechanism and clinical therapy of autism. Ten autistic children and ten healthy controls were examined with 99mTc-TRODAT-1 DAT SPECT imaging. Striatal specific uptake of 99mTc-TRODAT-1 was calculated with region of interest analysis according to the ratics between striatum and cerebellum [(STR-BKG)/BKG]. There was no statistically significant difference in semiquantitative dopamine transporter between the bilateral striata of autistic children (P=0.562), and between those of normal controls (p=0.573); Dopamine transporter in the brain of patients with autism increased significantly as compared with that in the brain of normal controls (P=0.017). Dopaminergic nervous system is dysfunctioning in the brain of children with autism, and DAT 99mTc-TRODAT-1 SPECT imaging on the brain will help the imaging diagnosis of childhcod autism.

LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome

PubMed Central

Chen, Chun; Miao, Changqing; Feng, Jianlin; Zhou, Yanli; Cao, Kejiang; Lloyd, Michael S.; Chen, Ji

2013-01-01

Purpose The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Methods Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2–3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Results Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4 %) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p<0.05). RFA improved LV synchrony in the entire cohort and in the patients with septal APs (p<0.01). Conclusion Phase analysis of gated SPECT MPI demonstrated that LV mechanical dyssynchrony can be present in patients with WPW syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI. PMID:22532253

Utility of ⁹⁹mTc-human serum albumin diethylenetriamine pentaacetic acid SPECT for evaluating endoleak after endovascular abdominal aortic aneurysm repair.

PubMed

Nakai, Motoki; Sato, Hirotatsu; Sato, Morio; Ikoma, Akira; Sonomura, Tetsuo; Nishimura, Yoshiharu; Okamura, Yoshitaka

2015-01-01

The purpose of this study was to assess the utility of (99m)Tc-human serum albumin diethylenetriamine pentaacetic acid ((99m)Tc-HSAD) SPECT in the detection of endoleaks after endovascular abdominal aortic aneurysm repair. Fifteen patients (11 men, four women) with aneurysm sac expansion of 5 mm or greater after endovascular abdominal aortic aneurysm repair underwent three-phase CT, (99m)Tc-HSAD SPECT, and CT during aortography. Sensitivity calculations for three-phase CT and (99m)Tc-HSAD SPECT were performed with CT during aortography as the reference standard. The volume of each endoleak was measured with CT during aortography. Seven subjects underwent embolization with N-butyl cyanoacrylate (NBCA)-Lipiodol (ethiodized oil, Guerbet and metallic coils. Three-phase CT and (99m)Tc-HSAD SPECT were repeated after embolization to assess their efficacy. Endoleaks were interpreted as perigraft radioisotope accumulation in 12 patients (80.0%) on (99m)Tc-HSAD SPECT images, in 13 patients (86.7%) on three-phase CT images, and in 15 patients (100%) on CT during aortography. The mean endoleak volume visualized with (99m)Tc-HSAD SPECT was 8.37 cm(3) (range, 5.2-15.1 cm(3)), and the volume not visualized was 3.47 cm(3) (2.5-4.6 cm(3)), a statistically significant difference (p = 0.019). In two patients, (99m)Tc-HSAD SPECT depicted endoleaks evident at delayed phase CT during aortography but not at three-phase CT, suggesting they were slow-filling endoleaks. Accumulation of (99m)Tc-HSAD corresponding to endoleaks disappeared after embolization, but CT evaluation of embolization was impeded by artifacts of NBCA-Lipiodol and metallic coils. Technetium-99m-labeled HSAD SPECT proved less sensitive than three-phase CT but depicted endoleaks with volumes 5.2 cm(3) or greater as perigraft radioisotope accumulation. Slow-filling endoleaks can be visualized with (99m)Tc-HSAD SPECT, which can be used to evaluate the efficacy of embolization.

Noise correlation in PET, CT, SPECT and PET/CT data evaluated using autocorrelation function: a phantom study on data, reconstructed using FBP and OSEM.

PubMed

Razifar, Pasha; Sandström, Mattias; Schnieder, Harald; Långström, Bengt; Maripuu, Enn; Bengtsson, Ewert; Bergström, Mats

2005-08-25

Positron Emission Tomography (PET), Computed Tomography (CT), PET/CT and Single Photon Emission Tomography (SPECT) are non-invasive imaging tools used for creating two dimensional (2D) cross section images of three dimensional (3D) objects. PET and SPECT have the potential of providing functional or biochemical information by measuring distribution and kinetics of radiolabelled molecules, whereas CT visualizes X-ray density in tissues in the body. PET/CT provides fused images representing both functional and anatomical information with better precision in localization than PET alone. Images generated by these types of techniques are generally noisy, thereby impairing the imaging potential and affecting the precision in quantitative values derived from the images. It is crucial to explore and understand the properties of noise in these imaging techniques. Here we used autocorrelation function (ACF) specifically to describe noise correlation and its non-isotropic behaviour in experimentally generated images of PET, CT, PET/CT and SPECT. Experiments were performed using phantoms with different shapes. In PET and PET/CT studies, data were acquired in 2D acquisition mode and reconstructed by both analytical filter back projection (FBP) and iterative, ordered subsets expectation maximisation (OSEM) methods. In the PET/CT studies, different magnitudes of X-ray dose in the transmission were employed by using different mA settings for the X-ray tube. In the CT studies, data were acquired using different slice thickness with and without applied dose reduction function and the images were reconstructed by FBP. SPECT studies were performed in 2D, reconstructed using FBP and OSEM, using post 3D filtering. ACF images were generated from the primary images, and profiles across the ACF images were used to describe the noise correlation in different directions. The variance of noise across the images was visualised as images and with profiles across these images. The most important finding was that the pattern of noise correlation is rotation symmetric or isotropic, independent of object shape in PET and PET/CT images reconstructed using the iterative method. This is, however, not the case in FBP images when the shape of phantom is not circular. Also CT images reconstructed using FBP show the same non-isotropic pattern independent of slice thickness and utilization of care dose function. SPECT images show an isotropic correlation of the noise independent of object shape or applied reconstruction algorithm. Noise in PET/CT images was identical independent of the applied X-ray dose in the transmission part (CT), indicating that the noise from transmission with the applied doses does not propagate into the PET images showing that the noise from the emission part is dominant. The results indicate that in human studies it is possible to utilize a low dose in transmission part while maintaining the noise behaviour and the quality of the images. The combined effect of noise correlation for asymmetric objects and a varying noise variance across the image field significantly complicates the interpretation of the images when statistical methods are used, such as with statistical estimates of precision in average values, use of statistical parametric mapping methods and principal component analysis. Hence it is recommended that iterative reconstruction methods are used for such applications. However, it is possible to calculate the noise analytically in images reconstructed by FBP, while it is not possible to do the same calculation in images reconstructed by iterative methods. Therefore for performing statistical methods of analysis which depend on knowing the noise, FBP would be preferred.

Noninvasive visualization of tumoral fibrin deposition using a peptidic fibrin-binding single photon emission computed tomography tracer.

PubMed

Starmans, Lucas W E; van Mourik, Tiemen; Rossin, Raffaella; Verel, Iris; Nicolay, Klaas; Grüll, Holger

2015-06-01

Fibrin deposition plays an important role in the formation of mature tumor stroma and provides a facilitating scaffold for tumor angiogenesis. This study investigates the potential of the (111)In-labeled fibrin-binding peptide EPep for SPECT imaging of intratumoral fibrin deposition. (111)In-EPep and negative control (111)In-NCEPep were synthesized and characterized in vitro. In vivo SPECT images and ex vivo biodistribution profiles and autoradiographs were obtained in a fibrin-rich BT-20 breast cancer mouse model. Furthermore, biodistribution profiles were obtained in the fibrin-poor MDA-MD-231 model. In vitro, (111)In-EPep displayed significantly more binding than (111)In-NCEPep toward human and mouse derived fibrin. SPECT/CT images displayed a marked SPECT signal in the tumor area for BT-20 tumor bearing mice injected with EPep but not for mice injected with NCEPep. Biodistribution profiles of BT-20 tumor bearing mice 3 h post-tracer injection showed significantly higher tumor uptake for EPep with respect to NCEPep (0.39 ± 0.14 and 0.11 ± 0.03% ID g(-1), respectively), whereas uptake in other organs was similar for EPep and NCEPep. Autoradiography of BT-20 tumor sections displayed a high signal for EPep which colocalized with intratumoral fibrin deposits. Histological evaluation of MDA-MB-231 tumor sections displayed no significant tumor stroma and only minute fibrin deposits. Biodistribution profiles in MDA-MB-231 tumor bearing mice 3 h post-injection showed EPep tumor uptake (0.14 ± 0.04% ID g(-1)) which was significantly lower with respect to EPep BT-20 tumor uptake, indicating fibrin-specificity of EPep tumoral uptake. In conclusion, this work demonstrates the potential of EPep SPECT imaging for visualization of tumoral fibrin deposition.

High-resolution clustered pinhole (131)Iodine SPECT imaging in mice.

PubMed

van der Have, Frans; Ivashchenko, Oleksandra; Goorden, Marlies C; Ramakers, Ruud M; Beekman, Freek J

2016-08-01

High-resolution pre-clinical (131)I SPECT can facilitate development of new radioiodine therapies for cancer. To this end, it is important to limit resolution-degrading effects of pinhole edge penetration by the high-energy γ-photons of iodine. Here we introduce, optimize and validate (131)I SPECT performed with a dedicated high-energy clustered multi-pinhole collimator. A SPECT-CT system (VECTor/CT) with stationary gamma-detectors was equipped with a tungsten collimator with clustered pinholes. Images were reconstructed with pixel-based OSEM, using a dedicated (131)I system matrix that models the distance- and energy-dependent resolution and sensitivity of each pinhole, as well as the intrinsic detector blurring and variable depth of interaction in the detector. The system performance was characterized with phantoms and in vivo static and dynamic (131)I-NaI scans of mice. Reconstructed image resolution reached 0.6mm, while quantitative accuracy measured with a (131)I filled syringe reaches an accuracy of +3.6±3.5% of the gold standard value. In vivo mice scans illustrated a clear shape of the thyroid and biodistribution of (131)I within the animal. Pharmacokinetics of (131)I was assessed with 15-s time frames from the sequence of dynamic images and time-activity curves of (131)I-NaI. High-resolution quantitative and fast dynamic (131)I SPECT in mice is possible by means of a high-energy collimator and optimized system modeling. This enables analysis of (131)I uptake even within small organs in mice, which can be highly valuable for development and optimization of targeted cancer therapies. Copyright © 2016 Elsevier Inc. All rights reserved.

Quantitative high-efficiency cadmium-zinc-telluride SPECT with dedicated parallel-hole collimation system in obese patients: results of a multi-center study.

PubMed

Nakazato, Ryo; Slomka, Piotr J; Fish, Mathews; Schwartz, Ronald G; Hayes, Sean W; Thomson, Louise E J; Friedman, John D; Lemley, Mark; Mackin, Maria L; Peterson, Benjamin; Schwartz, Arielle M; Doran, Jesse A; Germano, Guido; Berman, Daniel S

2015-04-01

Obesity is a common source of artifact on conventional SPECT myocardial perfusion imaging (MPI). We evaluated image quality and diagnostic performance of high-efficiency (HE) cadmium-zinc-telluride parallel-hole SPECT MPI for coronary artery disease (CAD) in obese patients. 118 consecutive obese patients at three centers (BMI 43.6 ± 8.9 kg·m(-2), range 35-79.7 kg·m(-2)) had upright/supine HE-SPECT and invasive coronary angiography > 6 months (n = 67) or low likelihood of CAD (n = 51). Stress quantitative total perfusion deficit (TPD) for upright (U-TPD), supine (S-TPD), and combined acquisitions (C-TPD) was assessed. Image quality (IQ; 5 = excellent; < 3 nondiagnostic) was compared among BMI 35-39.9 (n = 58), 40-44.9 (n = 24) and ≥45 (n = 36) groups. ROC curve area for CAD detection (≥50% stenosis) for U-TPD, S-TPD, and C-TPD were 0.80, 0.80, and 0.87, respectively. Sensitivity/specificity was 82%/57% for U-TPD, 74%/71% for S-TPD, and 80%/82% for C-TPD. C-TPD had highest specificity (P = .02). C-TPD normalcy rate was higher than U-TPD (88% vs 75%, P = .02). Mean IQ was similar among BMI 35-39.9, 40-44.9 and ≥45 groups [4.6 vs 4.4 vs 4.5, respectively (P = .6)]. No patient had a nondiagnostic stress scan. In obese patients, HE-SPECT MPI with dedicated parallel-hole collimation demonstrated high image quality, normalcy rate, and diagnostic accuracy for CAD by quantitative analysis of combined upright/supine acquisitions.

Quantitative High-Efficiency Cadmium-Zinc-Telluride SPECT with Dedicated Parallel-Hole Collimation System in Obese Patients: Results of a Multi-Center Study

PubMed Central

Nakazato, Ryo; Slomka, Piotr J.; Fish, Mathews; Schwartz, Ronald G.; Hayes, Sean W.; Thomson, Louise E.J.; Friedman, John D.; Lemley, Mark; Mackin, Maria L.; Peterson, Benjamin; Schwartz, Arielle M.; Doran, Jesse A.; Germano, Guido; Berman, Daniel S.

2014-01-01

Background Obesity is a common source of artifact on conventional SPECT myocardial perfusion imaging (MPI). We evaluated image quality and diagnostic performance of high-efficiency (HE) cadmium-zinc-telluride (CZT) parallel-hole SPECT-MPI for coronary artery disease (CAD) in obese patients. Methods and Results 118 consecutive obese patients at 3 centers (BMI 43.6±8.9 kg/m2, range 35–79.7 kg/m2) had upright/supine HE-SPECT and ICA >6 months (n=67) or low-likelihood of CAD (n=51). Stress quantitative total perfusion deficit (TPD) for upright (U-TPD), supine (S-TPD) and combined acquisitions (C-TPD) was assessed. Image quality (IQ; 5=excellent; <3 nondiagnostic) was compared among BMI 35–39.9 (n=58), 40–44.9 (n=24) and ≥45 (n=36) groups. ROC-curve area for CAD detection (≥50% stenosis) for U-TPD, S-TPD, and C-TPD were 0.80, 0.80, and 0.87, respectively. Sensitivity/specificity was 82%/57% for U-TPD, 74%/71% for S-TPD, and 80%/82% for C-TPD. C-TPD had highest specificity (P=.02). C-TPD normalcy rate was higher than U-TPD (88% vs. 75%, P=.02). Mean IQ was similar among BMI 35–39.9, 40–44.9 and ≥45 groups [4.6 vs. 4.4 vs. 4.5, respectively (P=.6)]. No patient had a non-diagnostic stress scan. Conclusions In obese patients, HE-SPECT MPI with dedicated parallel-hole collimation demonstrated high image quality, normalcy rate, and diagnostic accuracy for CAD by quantitative analysis of combined upright/supine acquisitions. PMID:25388380

The Effect of the Presence of EEG Leads on Image Quality in Cerebral Perfusion SPECT and FDG PET/CT.

PubMed

Zhang, Lulu; Yen, Stephanie P; Seltzer, Marc A; Thomas, George P; Willis, Kristen; Siegel, Alan

2018-06-08

Rationale: Cerebral perfusion SPECT and 18 F-FDG PET/CT are commonly performed diagnostic procedures for patients suffering from epilepsy. Individuals receiving these tests are often in-patients undergoing examinations with EEG leads. We have routinely removed these leads before these tests due to concerns that they would lead to imaging artifacts. The leads would then be replaced at the conclusion of the scan. The goal of our study was to determine if the EEG leads actually do cause artifacts that could lead to erroneous scan interpretation or make the scan uninterpretable. Methods: PET/CT with 18 F-FDG and SPECT with technetium-99m ECD were performed on a two dimensional brain phantom. The phantom was scanned with standard leads, CT/MR compatible leads and with no leads. The scans were interpreted by three experienced nuclear medicine physicians who were asked to rank the images by quality and then to determine if they could differentiate each of the scans from a scan in which it was indicated that no leads were present. Results: No differences could be detected between SPECT or PET scans performed without leads or with either set of leads. The standard EEG leads did create an artifact in the CT portion of the PET/CT while the CT/MR compatible leads did not. Conclusion: This phantom study suggest that EEG leads, standard or CT/MR compatible do not need to be removed for SPECT or for PET. Further study evaluating the effect on patients scan would be of value to support this conclusion. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Monitoring Cerebrovascular Reactivity through the Use of Arterial Spin Labeling in Patients with Moyamoya Disease.

PubMed

Yun, Tae Jin; Paeng, Jin Chul; Sohn, Chul-Ho; Kim, Jeong Eun; Kang, Hyun-Seung; Yoon, Byung-Woo; Choi, Seung Hong; Kim, Ji-hoon; Lee, Ho-Young; Han, Moon Hee; Zaharchuk, Greg

2016-01-01

To assess arterial spin labeling in the identification of impaired cerebrovascular reactivity in patients with moyamoya disease. The institutional review board approved this prospective study, and written informed consent was obtained from all patients. A prospective study was conducted in 78 subjects with moyamoya disease (of whom 31 underwent unilateral direct arterial anastomosis). The concordance between the cerebrovascular reactivity index values from arterial spin labeling and single photon emission computed tomography (SPECT) was assessed by using Bland-Altman analysis, and the area under the receiver operating characteristic curve was used to evaluate the diagnostic accuracy of arterial spin labeling to depict impaired cerebrovascular reactivity (in which the cerebrovascular reactivity index value is less than 0% on SPECT images). The cerebrovascular reactivity index from arterial spin labeling had a lower value than that from SPECT (mean difference, -4.2%). The area under the receiver operating characteristic curve for arterial spin labeling in the detection of impaired cerebrovascular reactivity was at least 0.85. On the anastomotic side, a significant increase was found between the cerebrovascular reactivity index values on arterial spin labeling images obtained preoperatively and those obtained 6 months after surgery, as well as on SPECT images (mean ± standard deviation values of cerebrovascular reactivity index increased by 5.9% ± 10.9 and 3.0% ± 6.3 for arterial spin labeling and SPECT, respectively). Arterial spin labeling has excellent performance in the identification of impaired cerebrovascular reactivity in patients with moyamoya disease, and it has the potential to serve as a noninvasive imaging tool to monitor cerebrovascular reactivity in patients with moyamoya disease. © RSNA, 2015

Segmentation of acute pyelonephritis area on kidney SPECT images using binary shape analysis

NASA Astrophysics Data System (ADS)

Wu, Chia-Hsiang; Sun, Yung-Nien; Chiu, Nan-Tsing

1999-05-01

Acute pyelonephritis is a serious disease in children that may result in irreversible renal scarring. The ability to localize the site of urinary tract infection and the extent of acute pyelonephritis has considerable clinical importance. In this paper, we are devoted to segment the acute pyelonephritis area from kidney SPECT images. A two-step algorithm is proposed. First, the original images are translated into binary versions by automatic thresholding. Then the acute pyelonephritis areas are located by finding convex deficiencies in the obtained binary images. This work gives important diagnosis information for physicians and improves the quality of medical care for children acute pyelonephritis disease.

Radiolabeled mannosylated dextran derivatives bearing an NIR-fluorophore for sentinel lymph node imaging.

PubMed

Morais, Maurício; Campello, Maria P C; Xavier, Catarina; Heemskerk, Johannes; Correia, João D G; Lahoutte, Tony; Caveliers, Vicky; Hernot, Sophie; Santos, Isabel

2014-11-19

Current methods for sentinel lymph node (SLN) mapping involve the use of radioactivity detection with technetium-99m sulfur colloid and/or visually guided identification using a blue dye. To overcome the kinetic variations of two individual imaging agents through the lymphatic system, we report herein on two multifunctional macromolecules, 5a and 6a, that contain a radionuclide ((99m)Tc or (68)Ga) and a near-infrared (NIR) reporter for pre- and/or intraoperative SLN mapping by nuclear and NIR optical imaging techniques. Both bimodal probes are dextran-based polymers (10 kDa) functionalized with pyrazole-diamine (Pz) or 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelating units for labeling with fac-[(99m)Tc(CO)3](+) or (68)Ga(III), respectively, mannose units for receptor targeting, and NIR fluorophore units for optical imaging. The probes allowed a clear visualization of the popliteal node by single-photon emission computed tomography (SPECT/CT) or positron emission tomography (PET/CT), as well as real-time optically guided excision. Biodistribution studies confirmed that both macromolecules present a significant accumulation in the popliteal node (5a: 3.87 ± 0.63% IA/organ; 6a: 1.04 ± 0.26% IA/organ), with minimal spread to other organs. The multifunctional nanoplatforms display a popliteal extraction efficiency >90%, highlighting their potential to be further explored as dual imaging agents.

Applications of Molecular Imaging

PubMed Central

Galbán, Craig; Galbán, Stefanie; Van Dort, Marcian; Luker, Gary D.; Bhojani, Mahaveer S.; Rehemtualla, Alnawaz; Ross, Brian D.

2015-01-01

Today molecular imaging technologies play a central role in clinical oncology. The use of imaging techniques in early cancer detection, treatment response and new therapy development is steadily growing and has already significantly impacted clinical management of cancer. In this chapter we will overview three different molecular imaging technologies used for the understanding of disease biomarkers, drug development, or monitoring therapeutic outcome. They are (1) optical imaging (bioluminescence and fluorescence imaging) (2) magnetic resonance imaging (MRI), and (3) nuclear imaging (e.g, single photon emission computed tomography (SPECT) and positron emission tomography (PET)). We will review the use of molecular reporters of biological processes (e.g. apoptosis and protein kinase activity) for high throughput drug screening and new cancer therapies, diffusion MRI as a biomarker for early treatment response and PET and SPECT radioligands in oncology. PMID:21075334

Comparison of LDPI to SPECT perfusion imaging using (99m)Tc-sestamibi and (99m)Tc-pyrophosphate in a murine ischemic hind limb model of neovascularization.

PubMed

Hendrikx, Geert; Vries, Mark H; Bauwens, Matthias; De Saint-Hubert, Marijke; Wagenaar, Allard; Guillaume, Joël; Boonen, Levinia; Post, Mark J; Mottaghy, Felix M

2016-12-01

We aimed to determine the accuracy of laser Doppler perfusion imaging (LDPI) in an animal model for hind limb ischemia. We used a murine (C57Bl/6 mice) ischemic hind limb model in which we compared LDPI with the clinically used (99m)Tc-sestamibi SPECT perfusion imaging (n = 7). In addition, we used the SPECT tracer (99m)Tc-pyrophosphate ((99m)Tc-PyP) to image muscular damage (n = 6). LDPI indicated a quick and prominent decrease in perfusion immediately after ligation, subsequently recovering to 21.9 and 25.2 % 14 days later in the (99m)Tc-sestamibi and (99m)Tc-PyP group, respectively. (99m)Tc-sestamibi SPECT scans also showed a quick decrease in perfusion. However, nearly full recovery was reached 7 days post ligation. Muscular damage, indicated by the uptake of (99m)Tc-PyP, was highest at day 3 and recovered to baseline levels at day 14 post ligation. Postmortem histology supported these findings, as a significantly increased collateral diameter was found 7 and 14 days after ligation and peak macrophage infiltration and TUNEL positivity was found on day 3 after ligation. Here, we indicate that LDPI strongly underestimates perfusion recovery in a hind limb model for profound ischemia.

Simulation of realistic abnormal SPECT brain perfusion images: application in semi-quantitative analysis

NASA Astrophysics Data System (ADS)

Ward, T.; Fleming, J. S.; Hoffmann, S. M. A.; Kemp, P. M.

2005-11-01

Simulation is useful in the validation of functional image analysis methods, particularly when considering the number of analysis techniques currently available lacking thorough validation. Problems exist with current simulation methods due to long run times or unrealistic results making it problematic to generate complete datasets. A method is presented for simulating known abnormalities within normal brain SPECT images using a measured point spread function (PSF), and incorporating a stereotactic atlas of the brain for anatomical positioning. This allows for the simulation of realistic images through the use of prior information regarding disease progression. SPECT images of cerebral perfusion have been generated consisting of a control database and a group of simulated abnormal subjects that are to be used in a UK audit of analysis methods. The abnormality is defined in the stereotactic space, then transformed to the individual subject space, convolved with a measured PSF and removed from the normal subject image. The dataset was analysed using SPM99 (Wellcome Department of Imaging Neuroscience, University College, London) and the MarsBaR volume of interest (VOI) analysis toolbox. The results were evaluated by comparison with the known ground truth. The analysis showed improvement when using a smoothing kernel equal to system resolution over the slightly larger kernel used routinely. Significant correlation was found between effective volume of a simulated abnormality and the detected size using SPM99. Improvements in VOI analysis sensitivity were found when using the region median over the region mean. The method and dataset provide an efficient methodology for use in the comparison and cross validation of semi-quantitative analysis methods in brain SPECT, and allow the optimization of analysis parameters.

Radionuclide bone scan SPECT-CT: lowering the dose of CT significantly reduces radiation dose without impacting CT image quality

PubMed Central

Gupta, Sandeep Kumar; Trethewey, Scott; Brooker, Bree; Rutherford, Natalie; Diffey, Jenny; Viswanathan, Suresh; Attia, John

2017-01-01

The CT component of SPECT-CT is required for attenuation correction and anatomical localization of the uptake on SPECT but there is no guideline about the optimal CT acquisition parameters. In our department, a standard CT acquisition protocol was changed in 2013 to give lower radiation dose to the patient. In this study, we retrospectively compared the effects on patient dose as well as the CT image quality with current versus older CT protocols. Ninety nine consecutive patients [n=51 Standard dose ‘old’ protocol (SDP); n=48 lower dose ‘new’ protocol (LDP)] with lumbar spine SPECT-CT for bone scan were examined. The main differences between the two protocols were that SDP used 130 kVp tube voltage and reference current-time product of 70 mAs whereas the LDP used 110 kVp and 40 mAs respectively. Various quantitative parameters from the CT images were obtained and the images were also rated blindly by two experienced nuclear medicine physicians for bony definition and noise. The mean calculated dose length product of the LDP group (121.5±39.6 mGy.cm) was significantly lower compared to the SDP group patients (266.9±96.9 mGy.cm; P<0.0001). This translated into a significant reduction in the mean effective dose to 1.8 mSv from 4.0 mSv. The physicians reported better CT image quality for the bony structures in LDP group although for soft tissue structures, the SDP group had better image quality. The optimized new CT acquisition protocol significantly reduced the radiation dose to the patient and in-fact improved CT image quality for the assessment of bony structures. PMID:28533938

Development and Validation of a Monte Carlo Simulation Tool for Multi-Pinhole SPECT

PubMed Central

Mok, Greta S. P.; Du, Yong; Wang, Yuchuan; Frey, Eric C.; Tsui, Benjamin M. W.

2011-01-01

Purpose In this work, we developed and validated a Monte Carlo simulation (MCS) tool for investigation and evaluation of multi-pinhole (MPH) SPECT imaging. Procedures This tool was based on a combination of the SimSET and MCNP codes. Photon attenuation and scatter in the object, as well as penetration and scatter through the collimator detector, are modeled in this tool. It allows accurate and efficient simulation of MPH SPECT with focused pinhole apertures and user-specified photon energy, aperture material, and imaging geometry. The MCS method was validated by comparing the point response function (PRF), detection efficiency (DE), and image profiles obtained from point sources and phantom experiments. A prototype single-pinhole collimator and focused four- and five-pinhole collimators fitted on a small animal imager were used for the experimental validations. We have also compared computational speed among various simulation tools for MPH SPECT, including SimSET-MCNP, MCNP, SimSET-GATE, and GATE for simulating projections of a hot sphere phantom. Results We found good agreement between the MCS and experimental results for PRF, DE, and image profiles, indicating the validity of the simulation method. The relative computational speeds for SimSET-MCNP, MCNP, SimSET-GATE, and GATE are 1: 2.73: 3.54: 7.34, respectively, for 120-view simulations. We also demonstrated the application of this MCS tool in small animal imaging by generating a set of low-noise MPH projection data of a 3D digital mouse whole body phantom. Conclusions The new method is useful for studying MPH collimator designs, data acquisition protocols, image reconstructions, and compensation techniques. It also has great potential to be applied for modeling the collimator-detector response with penetration and scatter effects for MPH in the quantitative reconstruction method. PMID:19779896

18F-FDG SPECT/CT in the diagnosis of differentiated thyroid carcinoma with elevated thyroglobulin and negative iodine-131 scans.

PubMed

Ma, C; Wang, X; Shao, M; Zhao, L; Jiawei, X; Wu, Z; Wang, H

2015-06-01

Aim of the present study was to investigate the usefulness of 18F-FDG SPECT/CT in differentiated thyroid cancer (DTC) with elevated serum thyroglobulin (Tg) but negative iodine-131 scan. This retrospective review of patients with DTC recurrence who had 18F-FDG SPECT/CT and 18F-FDG PET/CT for elevated serum Tg but negative iodine-131 scan (March 2007-October 2012). After total thyroidectomy followed by radioiodine ablation, 86 consecutive patients with elevated Tg levels underwent 18F-FDG SPECT/CT or 18F-FDG PET/CT. Of these, 45 patients had 18F-FDG SPECT/CT, the other 41 patients had 18F-FDG PET/CT 3-4weeks after thyroid hormone withdrawal. The results of 18F-FDG PET/CT and SPECT/CT were correlated with patient follow-up information, which included the results from subsequent imaging modalities such as neck ultrasound, MRI and CT, Tg levels, and histologic examination of surgical specimens. The diagnostic accuracy of the two imaging modalities was evaluated. In 18F-FDG SPECT/CT scans, 24 (24/45) patients had positive findings, 22 true positive in 24 patients, false positive in 2 patients, true-negative and false-negative in 6, 15 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG SPECT/CT were 59.5%, 75% and 62.2%, respectively. Twenty six patients had positive findings on 18F-FDG PET/CT scans, 23 true positive in 26 (26/41) patients, false positive in 3 patients, true-negative and false-negative in 9, 6 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG PET/CT were 79.3%, 81.8% and 78.1%, respectively. Clinical management changed for 13 (29%) of 45 patients by 18F-FDG SPECT/CT, 14 (34%) of 41 patients by 18F-FDG PET/CT including surgery, radiation therapy, or multikinase inhibitor. Based on the retrospective analysis of 86 patients, 18F-FDG SPECT/CT has lower sensitivity in the diagnosis of DTC recurrence with elevated Tg and negative iodine-131scan to 18F-FDG PET/CT. The clinical application of FDG SPECT/CT is then limited and cannot replace PET/CT.

Reproducibility of Lobar Perfusion and Ventilation Quantification Using SPECT/CT Segmentation Software in Lung Cancer Patients.

PubMed

Provost, Karine; Leblond, Antoine; Gauthier-Lemire, Annie; Filion, Édith; Bahig, Houda; Lord, Martin

2017-09-01

Planar perfusion scintigraphy with 99m Tc-labeled macroaggregated albumin is often used for pretherapy quantification of regional lung perfusion in lung cancer patients, particularly those with poor respiratory function. However, subdividing lung parenchyma into rectangular regions of interest, as done on planar images, is a poor reflection of true lobar anatomy. New tridimensional methods using SPECT and SPECT/CT have been introduced, including semiautomatic lung segmentation software. The present study evaluated inter- and intraobserver agreement on quantification using SPECT/CT software and compared the results for regional lung contribution obtained with SPECT/CT and planar scintigraphy. Methods: Thirty lung cancer patients underwent ventilation-perfusion scintigraphy with 99m Tc-macroaggregated albumin and 99m Tc-Technegas. The regional lung contribution to perfusion and ventilation was measured on both planar scintigraphy and SPECT/CT using semiautomatic lung segmentation software by 2 observers. Interobserver and intraobserver agreement for the SPECT/CT software was assessed using the intraclass correlation coefficient, Bland-Altman plots, and absolute differences in measurements. Measurements from planar and tridimensional methods were compared using the paired-sample t test and mean absolute differences. Results: Intraclass correlation coefficients were in the excellent range (above 0.9) for both interobserver and intraobserver agreement using the SPECT/CT software. Bland-Altman analyses showed very narrow limits of agreement. Absolute differences were below 2.0% in 96% of both interobserver and intraobserver measurements. There was a statistically significant difference between planar and SPECT/CT methods ( P < 0.001) for quantification of perfusion and ventilation for all right lung lobes, with a maximal mean absolute difference of 20.7% for the right middle lobe. There was no statistically significant difference in quantification of perfusion and ventilation for the left lung lobes using either method; however, absolute differences reached 12.0%. The total right and left lung contributions were similar for the two methods, with a mean difference of 1.2% for perfusion and 2.0% for ventilation. Conclusion: Quantification of regional lung perfusion and ventilation using SPECT/CT-based lung segmentation software is highly reproducible. This tridimensional method yields statistically significant differences in measurements for right lung lobes when compared with planar scintigraphy. We recommend that SPECT/CT-based quantification be used for all lung cancer patients undergoing pretherapy evaluation of regional lung function. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Multimodal fusion imaging ensemble for targeted sentinel lymph node management: initial results of an innovative promising approach for anatomically difficult lymphatic drainage in different tumour entities.

PubMed

Maza, Sofiane; Taupitz, Mathias; Taymoorian, Kasra; Winzer, Klaus Jürgen; Rückert, Jens; Paschen, Christian; Räber, Gert; Schneider, Sylke; Trefzer, Uwe; Munz, Dieter L

2007-03-01

There are situations where exact identification and localisation of sentinel lymph nodes (SLNs) are very difficult using lymphoscintigraphy, a hand-held gamma probe and vital dye, either a priori or a posteriori. We developed a new method using a simultaneous injection of two lymphotropic agents for exact topographical tomographic localisation and biopsy of draining SLNs. The purpose of this prospective pilot study was to investigate the feasibility and efficacy of this method ensemble. Fourteen patients with different tumour entities were enrolled. A mixture of (99m)Tc-nanocolloid and a dissolved superparamagnetic iron oxide was injected interstitially. Dynamic, sequential static lymphoscintigraphy and SPECT served as pathfinders. MR imaging was performed 2 h after injection. SPECT, contrast MRI and, if necessary, CT scan data sets were fused and evaluated with special regard to the topographical location of SLNs. The day after injection, nine patients underwent SLN biopsy and, in the presence of SLN metastasis, an elective lymph node dissection. Twenty-five SLNs were localised in the 14 patients examined. A 100% fusion correlation was achieved in all patients. The anatomical sites of SLNs detected during surgery showed 100% agreement with those localised on the multimodal fusion images. SLNs could be excised in 11/14 patients, six of whom had nodal metastasis. Our novel approach of multimodal fusion imaging for targeted SLN management in primary tumours with lymphatic drainage to anatomically difficult regions enables SLN biopsy even in patients with lymphatic drainage to obscure regions. Currently, we are testing its validity in larger patient groups and other tumour entities.

Synthesis and evaluation of novel radioiodinated nicotinamides for malignant melanoma.

PubMed

Liu, Xiang; Pham, Tien Q; Berghofer, Paula; Chapman, Janette; Greguric, Ivan; Mitchell, Peter; Mattner, Filomena; Loc'h, Christian; Katsifis, Andrew

2008-10-01

A series of iodonicotinamides based on the melanin-binding iodobenzamide compound N-2-diethylaminoethyl-4-iodobenzamide was prepared and evaluated for the potential imaging and staging of disseminated metastatic melanoma. [(123)I]Iodonicotinamides were prepared by iododestannylation reactions using no-carrier-added iodine-123 and evaluated in vivo by biodistribution and competition studies and by single photon emission computed tomography (SPECT) imaging in black and albino nude mice bearing B16F0 murine melanotic and A375 human amelanotic melanoma tumours, respectively. The iodonicotinamides displayed low-affinity binding for sigma(1)-sigma(2) receptors (K(i)>300 nM). In biodistribution studies in mice, N-(2-(diethylamino)ethyl)-5-[(123)I]iodonicotinamide ([(123)I]1) exhibited the fastest and highest uptake of the nicotinamide series in the B16F0 tumour at 1 h ( approximately 8% ID/g), decreasing slowly over time. No uptake was observed in the A375 tumour. Clearance from the animals by urinary excretion was more rapid for N-alkyl-nicotinamides than for piperazinyl derivatives. At 1 h postinjection, the urinary excretion was 66% ID for [(123)I]1, while the gastrointestinal tract amounted to 17% ID. Haloperidol was unable to reduce the uptake of [(123)I]1 in pigmented mice, indicating that this uptake was likely due to an interaction with melanin. SPECT imaging of [(123)I]1 in black mice bearing the B16F0 melanoma indicated that the radioactivity was predominately located in the tumour and eyes. No specific localisation was observed in nude mice bearing A375 amelanotic tumours. These findings suggest that [(123)I]1, which displays high tumour uptake with rapid clearance from the body, could be a promising imaging agent for the detection of melanotic tumours.

Development of (99m)Tc-labeled asymmetric urea derivatives that target prostate-specific membrane antigen for single-photon emission computed tomography imaging.

PubMed

Kimura, Hiroyuki; Sampei, Sotaro; Matsuoka, Daiko; Harada, Naoya; Watanabe, Hiroyuki; Arimitsu, Kenji; Ono, Masahiro; Saji, Hideo

2016-05-15

Prostate-specific membrane antigen (PSMA) is expressed strongly in prostate cancers and is, therefore, an attractive diagnostic and radioimmunotherapeutic target. In contrast to previous reports of PMSA-targeting (99m)Tc-tricarbonyl complexes that are cationic or lack a charge, no anionic (99m)Tc-tricarbonyl complexes have been reported. Notably, the hydrophilicity conferred by both cationic and anionic charges leads to rapid hepatobiliary clearance, whereas an anionic charge might better enhance renal clearance relative to a cationic charge. Therefore, an improvement in rapid clearance would be expected with either cationic or anionic charges, particularly anionic charges. In this study, we designed and synthesized a novel anionic (99m)Tc-tricarbonyl complex ([(99m)Tc]TMCE) and evaluated its use as a single-photon emission computed tomography (SPECT) imaging probe for PSMA detection. Direct synthesis of [(99m)Tc]TMCE from dimethyl iminodiacetate, which contains both the asymmetric urea and succinimidyl moiety important for PSMA binding, was performed using our microwave-assisted one-pot procedure. The chelate formation was successfully achieved even though the precursor included a complicated bioactive moiety. The radiochemical yield of [(99m)Tc]TMCE was 12-17%, with a radiochemical purity greater than 98% after HPLC purification. [(99m)Tc]TMCE showed high affinity in vitro, with high accumulation in LNCaP tumors and low hepatic retention in biodistribution and SPECT/CT studies. These findings warrant further evaluation of [(99m)Tc]TMCE as an imaging agent and support the benefit of this strategy for the design of other PSMA imaging probes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Theranostics Using Antibodies and Antibody-Related Therapeutics.

PubMed

Moek, Kirsten L; Giesen, Danique; Kok, Iris C; de Groot, Derk Jan A; Jalving, Mathilde; Fehrmann, Rudolf S N; Lub-de Hooge, Marjolijn N; Brouwers, Adrienne H; de Vries, Elisabeth G E

2017-09-01

In theranostics, radiolabeled compounds are used to determine a treatment strategy by combining therapeutics and diagnostics in the same agent. Monoclonal antibodies (mAbs) and antibody-related therapeutics represent a rapidly expanding group of cancer medicines. Theranostic approaches using these drugs in oncology are particularly interesting because antibodies are designed against specific targets on the tumor cell membrane and immune cells as well as targets in the tumor microenvironment. In addition, these drugs are relatively easy to radiolabel. Noninvasive molecular imaging techniques, such as SPECT and PET, provide information on the whole-body distribution of radiolabeled mAbs and antibody-related therapeutics. Molecular antibody imaging can potentially elucidate drug target expression, tracer uptake in the tumor, tumor saturation, and heterogeneity for these parameters within the tumor. These data can support drug development and may aid in patient stratification and monitoring of the treatment response. Selecting a radionuclide for theranostic purposes generally starts by matching the serum half-life of the mAb or antibody-related therapeutic and the physical half-life of the radionuclide. Furthermore, PET imaging allows better quantification than the SPECT technique. This information has increased interest in theranostics using PET radionuclides with a relatively long physical half-life, such as 89 Zr. In this review, we provide an overview of ongoing research on mAbs and antibody-related theranostics in preclinical and clinical oncologic settings. We identified 24 antibodies or antibody-related therapeutics labeled with PET radionuclides for theranostic purposes in patients. For this approach to become integrated in standard care, further standardization with respect to the procedures involved is required. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

MO-AB-206-02: Testing Gamma Cameras Based On TG177 WG Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halama, J.

2016-06-15

This education session will cover the physics and operation principles of gamma cameras and PET scanners. The first talk will focus on PET imaging. An overview of the principles of PET imaging will be provided, including positron decay physics, and the transition from 2D to 3D imaging. More recent advances in hardware and software will be discussed, such as time-of-flight imaging, and improvements in reconstruction algorithms that provide for options such as depth-of-interaction corrections. Quantitative applications of PET will be discussed, as well as the requirements for doing accurate quantitation. Relevant performance tests will also be described. Learning Objectives: Bemore » able to describe basic physics principles of PET and operation of PET scanners. Learn about recent advances in PET scanner hardware technology. Be able to describe advances in reconstruction techniques and improvements Be able to list relevant performance tests. The second talk will focus on gamma cameras. The Nuclear Medicine subcommittee has charged a task group (TG177) to develop a report on the current state of physics testing of gamma cameras, SPECT, and SPECT/CT systems. The report makes recommendations for performance tests to be done for routine quality assurance, annual physics testing, and acceptance tests, and identifies those needed satisfy the ACR accreditation program and The Joint Commission imaging standards. The report is also intended to be used as a manual with detailed instructions on how to perform tests under widely varying conditions. Learning Objectives: At the end of the presentation members of the audience will: Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of gamma cameras for planar imaging. Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of SPECT systems. Be familiar with the tests of a SPECT/CT system that include the CT images for SPECT reconstructions. Become knowledgeable of items to be included in annual acceptance testing reports including CT dosimetry and PACS monitor measurements. T. Turkington, GE Healthcare.« less

MO-AB-206-00: Nuclear Medicine Physics and Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This education session will cover the physics and operation principles of gamma cameras and PET scanners. The first talk will focus on PET imaging. An overview of the principles of PET imaging will be provided, including positron decay physics, and the transition from 2D to 3D imaging. More recent advances in hardware and software will be discussed, such as time-of-flight imaging, and improvements in reconstruction algorithms that provide for options such as depth-of-interaction corrections. Quantitative applications of PET will be discussed, as well as the requirements for doing accurate quantitation. Relevant performance tests will also be described. Learning Objectives: Bemore » able to describe basic physics principles of PET and operation of PET scanners. Learn about recent advances in PET scanner hardware technology. Be able to describe advances in reconstruction techniques and improvements Be able to list relevant performance tests. The second talk will focus on gamma cameras. The Nuclear Medicine subcommittee has charged a task group (TG177) to develop a report on the current state of physics testing of gamma cameras, SPECT, and SPECT/CT systems. The report makes recommendations for performance tests to be done for routine quality assurance, annual physics testing, and acceptance tests, and identifies those needed satisfy the ACR accreditation program and The Joint Commission imaging standards. The report is also intended to be used as a manual with detailed instructions on how to perform tests under widely varying conditions. Learning Objectives: At the end of the presentation members of the audience will: Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of gamma cameras for planar imaging. Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of SPECT systems. Be familiar with the tests of a SPECT/CT system that include the CT images for SPECT reconstructions. Become knowledgeable of items to be included in annual acceptance testing reports including CT dosimetry and PACS monitor measurements. T. Turkington, GE Healthcare.« less

Single photon emission computed tomography (SPECT) in epilepsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leroy, R.F.

1991-12-31

Epilepsy is a common neurologic disorder which has just begun to be studied with single photon emission computerized tomography (SPECT). Epilepsy usually is studied with electroencephalographic (EEG) techniques that demonstrate the physiologic changes that occur during seizures, and with neuroimaging techniques that show the brain structures where seizures originate. Neither method alone has been adequate to describe the pathophysiology of the patient with epilepsy. EEG techniques lack anatomic sensitivity, and there are no structural abnormalities shown by neuroimaging which are specific for epilepsy. Functional imaging (FI) has developed as a physiologic tool with anatomic sensitivity, and SPECT has been promotedmore » as a FI technique because of its potentially wide availability. However, SPECT is early in its development and its clinical utility for epilepsy still has to be demonstrated. To understand this role of SPECT, consideration must be given to the pathophysiology of epilepsy, brain physiology, types of seizure, epileptic syndromes, and the SPECT technique itself. 44 refs., 2 tabs.« less

Prompt gamma-ray imaging for small animals

NASA Astrophysics Data System (ADS)

Xu, Libai

Small animal imaging is recognized as a powerful discovery tool for small animal modeling of human diseases, which is providing an important clue to complete understanding of disease mechanisms and is helping researchers develop and test new treatments. The current small animal imaging techniques include positron emission tomography (PET), single photon emission tomography (SPECT), computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US). A new imaging modality called prompt gamma-ray imaging (PGI) has been identified and investigated primarily by Monte Carlo simulation. Currently it is suggested for use on small animals. This new technique could greatly enhance and extend the present capabilities of PET and SPECT imaging from ingested radioisotopes to the imaging of selected non-radioactive elements, such as Gd, Cd, Hg, and B, and has the great potential to be used in Neutron Cancer Therapy to monitor neutron distribution and neutron-capture agent distribution. This approach consists of irradiating small animals in the thermal neutron beam of a nuclear reactor to produce prompt gamma rays from the elements in the sample by the radiative capture (n, gamma) reaction. These prompt gamma rays are emitted in energies that are characteristic of each element and they are also produced in characteristic coincident chains. After measuring these prompt gamma rays by surrounding spectrometry array, the distribution of each element of interest in the sample is reconstructed from the mapping of each detected signature gamma ray by either electronic collimations or mechanical collimations. In addition, the transmitted neutrons from the beam can be simultaneously used for very sensitive anatomical imaging, which provides the registration for the elemental distributions obtained from PGI. The primary approach is to use Monte Carlo simulation methods either with the specific purpose code CEARCPG, developed at NC State University or with the general purpose codes GEANT4 or MCNP5, to predict results and investigate the feasibility of this new imaging idea. Benchmark experiments have been conducted to test the capability of the code to simulate prompt gamma rays, which are produced by following the nuclear structures of each irradiated isotope, and coincidence counting techniques, which are considered the most important improvement in neutron-related gamma-ray detection applications to reduce gamma background and improve system signal-to-noise ratios. With coincidence prompt gamma rays available, two major imaging techniques, electronic collimations and mechanic collimations, are implemented in the simulation to illustrate the feasibility of imaging elemental distribution by this new technique. The expectation maximization algorithm is employed in electronic collimation to reconstruct images. The common SPECT imaging algorithms are used in mechanical collimation to get an image. Several critical topics concerning practical applications have already been discussed, such as the radiation dose to the mouse and the detection efficiency of high-energy gamma rays. The funding of this work is provided by the Center for Engineering Application of Radioisotopes (CEAR) at North Carolina State University (NCSU) and Nuclear Engineering Education Research.

Performance characterization of a new CZT-based preclinical SPECT system: a comparative study of different collimators

NASA Astrophysics Data System (ADS)

Yu, A. R.; Park, S.-J.; Choi, Y. Y.; Kim, K. M.; Kim, H.-J.

2015-09-01

Triumph X-SPECT is a newly released CZT-based preclinical small-animal SPECT system with interchangeable collimators. The purpose of this work was to evaluate and systematically compare the imaging performances of three different collimators in the CZT-based preclinical small-animal system: a single-pinhole collimator (SPH), a multi-pinhole collimator (MPH) and a parallel-hole collimator. We measured the spatial resolutions and sensitivities of the three collimators with 99mTc sources, considering three distinct energy window widths (5, 10, and 20%), and used the NEMA NU4-2008 Image Quality phantom to test the imaging performance of the three collimators in terms of uniformity and spill-over ratio (SOR) for each energy window. With a 10% energy window width at a radius of rotation (ROR) of 30 mm, the system resolution of the SPH, MPH and parallel-hole collimators was 0.715, 0.855 and 3.270 mm FWHM, respectively. For the same energy window, the sensitivity of the system with SPH, MPH and parallel-hole collimators was 32.860, 152.514 and 49.205 counts/sec/MBq at a 100 mm source-to-detector distance and 6.790, 33.376 and 49.038 counts/sec/MBq at a 130 mm source-to-detector distance, respectively. The image noise and SORair for the three collimators were 20.137, 12.278 and 11.232 (%STDunif) and 0.106, 0.140 and 0.161, respectively. Overall, the results show that the SPH had better spatial resolution than the other collimators. The MPH had the highest sensitivity at 100 mm source-to-collimator distance, and the parallel-hole collimator had the highest sensitivity at 130 mm-source-to-detector distance. Therefore, the proper collimator for Triumph X-SPECT system must be determined by the task. These results provide valuable reference data and insight into the imaging performance of various collimators in CZT-based preclinical small-animal SPECT.

Review of running injuries of the foot and ankle: clinical presentation and SPECT-CT imaging patterns

PubMed Central

Pelletier-Galarneau, Matthieu; Martineau, Patrick; Gaudreault, Maxime; Pham, Xuan

2015-01-01

Distance running is among the fastest growing sports, with record registration to marathons worldwide. It is estimated that more than half of recreational runners will experience injuries related to the practice of their sport. Three-phase bone scintigraphy is a very sensitive tool to identify sports injury, allowing imaging of hyperemia, stress reaction, enthesopathy and fractures, often before abnormalities can be detected on conventional anatomical modalities. In this article, we review the most common running related injuries and their imaging findings on bone scintigraphy with SPECT-CT. PMID:26269770

Design and assessment of a novel SPECT system for desktop open-gantry imaging of small animals: A simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeraatkar, Navid; Farahani, Mohammad Hossein; Rahmim, Arman

Purpose: Given increasing efforts in biomedical research utilizing molecular imaging methods, development of dedicated high-performance small-animal SPECT systems has been growing rapidly in the last decade. In the present work, we propose and assess an alternative concept for SPECT imaging enabling desktop open-gantry imaging of small animals. Methods: The system, PERSPECT, consists of an imaging desk, with a set of tilted detector and pinhole collimator placed beneath it. The object to be imaged is simply placed on the desk. Monte Carlo (MC) and analytical simulations were utilized to accurately model and evaluate the proposed concept and design. Furthermore, a dedicatedmore » image reconstruction algorithm, finite-aperture-based circular projections (FABCP), was developed and validated for the system, enabling more accurate modeling of the system and higher quality reconstructed images. Image quality was quantified as a function of different tilt angles in the acquisition and number of iterations in the reconstruction algorithm. Furthermore, more complex phantoms including Derenzo, Defrise, and mouse whole body were simulated and studied. Results: The sensitivity of the PERSPECT was 207 cps/MBq. It was quantitatively demonstrated that for a tilt angle of 30°, comparable image qualities were obtained in terms of normalized squared error, contrast, uniformity, noise, and spatial resolution measurements, the latter at ∼0.6 mm. Furthermore, quantitative analyses demonstrated that 3 iterations of FABCP image reconstruction (16 subsets/iteration) led to optimally reconstructed images. Conclusions: The PERSPECT, using a novel imaging protocol, can achieve comparable image quality performance in comparison with a conventional pinhole SPECT with the same configuration. The dedicated FABCP algorithm, which was developed for reconstruction of data from the PERSPECT system, can produce high quality images for small-animal imaging via accurate modeling of the system as incorporated in the forward- and back-projection steps. Meanwhile, the developed MC model and the analytical simulator of the system can be applied for further studies on development and evaluation of the system.« less

Integration of SimSET photon history generator in GATE for efficient Monte Carlo simulations of pinhole SPECT.

PubMed

Chen, Chia-Lin; Wang, Yuchuan; Lee, Jason J S; Tsui, Benjamin M W

2008-07-01

The authors developed and validated an efficient Monte Carlo simulation (MCS) workflow to facilitate small animal pinhole SPECT imaging research. This workflow seamlessly integrates two existing MCS tools: simulation system for emission tomography (SimSET) and GEANT4 application for emission tomography (GATE). Specifically, we retained the strength of GATE in describing complex collimator/detector configurations to meet the anticipated needs for studying advanced pinhole collimation (e.g., multipinhole) geometry, while inserting the fast SimSET photon history generator (PHG) to circumvent the relatively slow GEANT4 MCS code used by GATE in simulating photon interactions inside voxelized phantoms. For validation, data generated from this new SimSET-GATE workflow were compared with those from GATE-only simulations as well as experimental measurements obtained using a commercial small animal pinhole SPECT system. Our results showed excellent agreement (e.g., in system point response functions and energy spectra) between SimSET-GATE and GATE-only simulations, and, more importantly, a significant computational speedup (up to approximately 10-fold) provided by the new workflow. Satisfactory agreement between MCS results and experimental data were also observed. In conclusion, the authors have successfully integrated SimSET photon history generator in GATE for fast and realistic pinhole SPECT simulations, which can facilitate research in, for example, the development and application of quantitative pinhole and multipinhole SPECT for small animal imaging. This integrated simulation tool can also be adapted for studying other preclinical and clinical SPECT techniques.

A new SPECT/CT reconstruction algorithm: reliability and accuracy in clinical routine for non-oncologic bone diseases.

PubMed

Delcroix, Olivier; Robin, Philippe; Gouillou, Maelenn; Le Duc-Pennec, Alexandra; Alavi, Zarrin; Le Roux, Pierre-Yves; Abgral, Ronan; Salaun, Pierre-Yves; Bourhis, David; Querellou, Solène

2018-02-12

xSPECT Bone® (xB) is a new reconstruction algorithm developed by Siemens® in bone hybrid imaging (SPECT/CT). A CT-based tissue segmentation is incorporated into SPECT reconstruction to provide SPECT images with bone anatomy appearance. The objectives of this study were to assess xB/CT reconstruction diagnostic reliability and accuracy in comparison with Flash 3D® (F3D)/CT in clinical routine. Two hundred thirteen consecutive patients referred to the Brest Nuclear Medicine Department for non-oncological bone diseases were evaluated retrospectively. Two hundred seven SPECT/CT were included. All SPECT/CT were independently interpreted by two nuclear medicine physicians (a junior and a senior expert) with xB/CT then with F3D/CT three months later. Inter-observer agreement (IOA) and diagnostic confidence were determined using McNemar test, and unweighted Kappa coefficient. The study objectives were then re-assessed for validation through > 18 months of clinical and paraclinical follow-up. No statistically significant differences between IOA xB and IOA F3D were found (p = 0.532). Agreement for xB after categorical classification of the diagnoses was high (κ xB = 0.89 [95% CI 0.84 -0.93]) but without statistically significant difference F3D (κ F3D = 0.90 [95% CI 0.86 - 0.94]). Thirty-one (14.9%) inter-reconstruction diagnostic discrepancies were observed of which 21 (10.1%) were classified as major. The follow-up confirmed the diagnosis of F3D in 10 cases, xB in 6 cases and was non-contributory in 5 cases. xB reconstruction algorithm was found reliable, providing high interobserver agreement and similar diagnostic confidence to F3D reconstruction in clinical routine.

Post traumatic brain perfusion SPECT analysis using reconstructed ROI maps of radioactive microsphere derived cerebral blood flow and statistical parametric mapping

PubMed Central

McGoron, Anthony J; Capille, Michael; Georgiou, Michael F; Sanchez, Pablo; Solano, Juan; Gonzalez-Brito, Manuel; Kuluz, John W

2008-01-01

Background Assessment of cerebral blood flow (CBF) by SPECT could be important in the management of patients with severe traumatic brain injury (TBI) because changes in regional CBF can affect outcome by promoting edema formation and intracranial pressure elevation (with cerebral hyperemia), or by causing secondary ischemic injury including post-traumatic stroke. The purpose of this study was to establish an improved method for evaluating regional CBF changes after TBI in piglets. Methods The focal effects of moderate traumatic brain injury (TBI) on cerebral blood flow (CBF) by SPECT cerebral blood perfusion (CBP) imaging in an animal model were investigated by parallelized statistical techniques. Regional CBF was measured by radioactive microspheres and by SPECT 2 hours after injury in sham-operated piglets versus those receiving severe TBI by fluid-percussion injury to the left parietal lobe. Qualitative SPECT CBP accuracy was assessed against reference radioactive microsphere regional CBF measurements by map reconstruction, registration and smoothing. Cerebral hypoperfusion in the test group was identified at the voxel level using statistical parametric mapping (SPM). Results A significant area of hypoperfusion (P < 0.01) was found as a response to the TBI. Statistical mapping of the reference microsphere CBF data confirms a focal decrease found with SPECT and SPM. Conclusion The suitability of SPM for application to the experimental model and ability to provide insight into CBF changes in response to traumatic injury was validated by the SPECT SPM result of a decrease in CBP at the left parietal region injury area of the test group. Further study and correlation of this characteristic lesion with long-term outcomes and auxiliary diagnostic modalities is critical to developing more effective critical care treatment guidelines and automated medical imaging processing techniques. PMID:18312639

Post traumatic brain perfusion SPECT analysis using reconstructed ROI maps of radioactive microsphere derived cerebral blood flow and statistical parametric mapping.

PubMed

McGoron, Anthony J; Capille, Michael; Georgiou, Michael F; Sanchez, Pablo; Solano, Juan; Gonzalez-Brito, Manuel; Kuluz, John W

2008-02-29

Assessment of cerebral blood flow (CBF) by SPECT could be important in the management of patients with severe traumatic brain injury (TBI) because changes in regional CBF can affect outcome by promoting edema formation and intracranial pressure elevation (with cerebral hyperemia), or by causing secondary ischemic injury including post-traumatic stroke. The purpose of this study was to establish an improved method for evaluating regional CBF changes after TBI in piglets. The focal effects of moderate traumatic brain injury (TBI) on cerebral blood flow (CBF) by SPECT cerebral blood perfusion (CBP) imaging in an animal model were investigated by parallelized statistical techniques. Regional CBF was measured by radioactive microspheres and by SPECT 2 hours after injury in sham-operated piglets versus those receiving severe TBI by fluid-percussion injury to the left parietal lobe. Qualitative SPECT CBP accuracy was assessed against reference radioactive microsphere regional CBF measurements by map reconstruction, registration and smoothing. Cerebral hypoperfusion in the test group was identified at the voxel level using statistical parametric mapping (SPM). A significant area of hypoperfusion (P < 0.01) was found as a response to the TBI. Statistical mapping of the reference microsphere CBF data confirms a focal decrease found with SPECT and SPM. The suitability of SPM for application to the experimental model and ability to provide insight into CBF changes in response to traumatic injury was validated by the SPECT SPM result of a decrease in CBP at the left parietal region injury area of the test group. Further study and correlation of this characteristic lesion with long-term outcomes and auxiliary diagnostic modalities is critical to developing more effective critical care treatment guidelines and automated medical imaging processing techniques.

High spatial resolution technique for SPECT using a fan-beam collimator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ichihar, T.; Nambu, K.; Motomura, N.

1993-08-01

The physical characteristics of the collimator cause degradation of resolution with increasing distance from the collimator surface. A new convolutional backprojection algorithm has been derived for fanbeam SPECT data without rebinding into parallel beam geometry. The projections are filtered and then backprojected into the area within an isosceles triangle whose vertex is the focal point of the fan-beam and whose base is the fan-beam collimator face, and outside of the circle whose center is located midway between the focal point and the center of rotation and whose diameter is the distance between the focal point and the center of rotation.more » Consequently the backprojected area is close to the collimator surface. This algorithm has been implemented on a GCA-9300A SPECT system showing good results with both phantom and patient studies. The SPECT transaxial resolution was 4.6mm FWHM (reconstructed image matrix size of 256x256) at the center of SPECT FOV using UHR (ultra-high-resolution) fan beam collimators for brain study. Clinically, Tc-99m HMPAO and Tc-99m ECD brain data were reconstructed using this algorithm. The reconstruction results were compared with MRI images of the same slice position and showed significantly improved over results obtained with standard reconstruction algorithms.« less

Image quality phantom and parameters for high spatial resolution small-animal SPECT

NASA Astrophysics Data System (ADS)

Visser, Eric P.; Harteveld, Anita A.; Meeuwis, Antoi P. W.; Disselhorst, Jonathan A.; Beekman, Freek J.; Oyen, Wim J. G.; Boerman, Otto C.

2011-10-01

At present, generally accepted standards to characterize small-animal single photon emission tomographs (SPECT) do not exist. Whereas for small-animal positron emission tomography (PET), the NEMA NU 4-2008 guidelines are available, such standards are still lacking for small-animal SPECT. More specifically, a dedicated image quality (IQ) phantom and corresponding IQ parameters are absent. The structures of the existing PET IQ phantom are too large to fully characterize the sub-millimeter spatial resolution of modern multi-pinhole SPECT scanners, and its diameter will not fit into all scanners when operating in high spatial resolution mode. We therefore designed and constructed an adapted IQ phantom with smaller internal structures and external diameter, and a facility to guarantee complete filling of the smallest rods. The associated IQ parameters were adapted from NEMA NU 4. An additional parameter, effective whole-body sensitivity, was defined since this was considered relevant in view of the variable size of the field of view and the use of multiple bed positions as encountered in modern small-animal SPECT scanners. The usefulness of the phantom was demonstrated for 99mTc in a USPECT-II scanner operated in whole-body scanning mode using a multi-pinhole mouse collimator with 0.6 mm pinhole diameter.

New SPECT and PET Radiopharmaceuticals for Imaging Cardiovascular Disease

PubMed Central

Sogbein, Oyebola O.; Pelletier-Galarneau, Matthieu; Schindler, Thomas H.; Wei, Lihui; Wells, R. Glenn; Ruddy, Terrence D.

2014-01-01

Nuclear cardiology has experienced exponential growth within the past four decades with converging capacity to diagnose and influence management of a variety of cardiovascular diseases. Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with technetium-99m radiotracers or thallium-201 has dominated the field; however new hardware and software designs that optimize image quality with reduced radiation exposure are fuelling a resurgence of interest at the preclinical and clinical levels to expand beyond MPI. Other imaging modalities including positron emission tomography (PET) and magnetic resonance imaging (MRI) continue to emerge as powerful players with an expanded capacity to diagnose a variety of cardiac conditions. At the forefront of this resurgence is the development of novel target vectors based on an enhanced understanding of the underlying pathophysiological process in the subcellular domain. Molecular imaging with novel radiopharmaceuticals engineered to target a specific subcellular process has the capacity to improve diagnostic accuracy and deliver enhanced prognostic information to alter management. This paper, while not comprehensive, will review the recent advancements in radiotracer development for SPECT and PET MPI, autonomic dysfunction, apoptosis, atherosclerotic plaques, metabolism, and viability. The relevant radiochemistry and preclinical and clinical development in addition to molecular imaging with emerging modalities such as cardiac MRI and PET-MR will be discussed. PMID:24901002

NOTE: Implementation of angular response function modeling in SPECT simulations with GATE

NASA Astrophysics Data System (ADS)

Descourt, P.; Carlier, T.; Du, Y.; Song, X.; Buvat, I.; Frey, E. C.; Bardies, M.; Tsui, B. M. W.; Visvikis, D.

2010-05-01

Among Monte Carlo simulation codes in medical imaging, the GATE simulation platform is widely used today given its flexibility and accuracy, despite long run times, which in SPECT simulations are mostly spent in tracking photons through the collimators. In this work, a tabulated model of the collimator/detector response was implemented within the GATE framework to significantly reduce the simulation times in SPECT. This implementation uses the angular response function (ARF) model. The performance of the implemented ARF approach has been compared to standard SPECT GATE simulations in terms of the ARF tables' accuracy, overall SPECT system performance and run times. Considering the simulation of the Siemens Symbia T SPECT system using high-energy collimators, differences of less than 1% were measured between the ARF-based and the standard GATE-based simulations, while considering the same noise level in the projections, acceleration factors of up to 180 were obtained when simulating a planar 364 keV source seen with the same SPECT system. The ARF-based and the standard GATE simulation results also agreed very well when considering a four-head SPECT simulation of a realistic Jaszczak phantom filled with iodine-131, with a resulting acceleration factor of 100. In conclusion, the implementation of an ARF-based model of collimator/detector response for SPECT simulations within GATE significantly reduces the simulation run times without compromising accuracy.

Technological advances in hybrid imaging and impact on dose.

PubMed

Mattsson, Sören; Andersson, Martin; Söderberg, Marcus

2015-07-01

New imaging technologies utilising X-rays and radiopharmaceuticals have developed rapidly. Clinical application of computed tomography (CT) has revolutionised medical imaging and plays an enormous role in medical care. Due to technical improvements, spatial, contrast and temporal resolutions have continuously improved. In spite of significant reduction of CT doses during recent years, CT is still a dominating source of radiation exposure to the population. Combinations with single photon emission computed tomography (SPECT) and positron emission tomography (PET) and especially the use of SPECT/CT and PET/CT, provide important additional information about physiology as well as cellular and molecular events. However, significant dose contributions from SPECT and PET occur, making PET/CT and SPECT/CT truly high dose procedures. More research should be done to find optimal activities of radiopharmaceuticals for various patient groups and investigations. The implementation of simple protocol adjustments, including individually based administration, encouraged hydration, forced diuresis and use of optimised voiding intervals, laxatives, etc., can reduce the radiation exposure to the patients. New data about staff doses to fingers, hands and eye lenses indicate that finger doses could be a problem, but not doses to the eye lenses and to the whole body. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Validation of the Monte Carlo simulator GATE for indium-111 imaging.

PubMed

Assié, K; Gardin, I; Véra, P; Buvat, I

2005-07-07

Monte Carlo simulations are useful for optimizing and assessing single photon emission computed tomography (SPECT) protocols, especially when aiming at measuring quantitative parameters from SPECT images. Before Monte Carlo simulated data can be trusted, the simulation model must be validated. The purpose of this work was to validate the use of GATE, a new Monte Carlo simulation platform based on GEANT4, for modelling indium-111 SPECT data, the quantification of which is of foremost importance for dosimetric studies. To that end, acquisitions of (111)In line sources in air and in water and of a cylindrical phantom were performed, together with the corresponding simulations. The simulation model included Monte Carlo modelling of the camera collimator and of a back-compartment accounting for photomultiplier tubes and associated electronics. Energy spectra, spatial resolution, sensitivity values, images and count profiles obtained for experimental and simulated data were compared. An excellent agreement was found between experimental and simulated energy spectra. For source-to-collimator distances varying from 0 to 20 cm, simulated and experimental spatial resolution differed by less than 2% in air, while the simulated sensitivity values were within 4% of the experimental values. The simulation of the cylindrical phantom closely reproduced the experimental data. These results suggest that GATE enables accurate simulation of (111)In SPECT acquisitions.

ROC evaluation of SPECT myocardial lesion detectability with and without single iteration non-uniform Chang attenuation compensation using an anthropomorphic female phantom

NASA Astrophysics Data System (ADS)

Jang, Sunyoung; Jaszczak, R. J.; Tsui, B. M. W.; Metz, C. E.; Gilland, D. R.; Turkington, T. G.; Coleman, R. E.

1998-08-01

The purpose of this work was to evaluate lesion detectability with and without nonuniform attenuation compensation (AC) in myocardial perfusion SPECT imaging in women using an anthropomorphic phantom and receiver operating characteristics (ROC) methodology. Breast attenuation causes artifacts in reconstructed images and may increase the difficulty of diagnosis of myocardial perfusion imaging in women. The null hypothesis tested using the ROC study was that nonuniform AC does not change the lesion detectability in myocardial perfusion SPECT imaging in women. The authors used a filtered backprojection (FBP) reconstruction algorithm and Chang's (1978) single iteration method for AC. In conclusion, with the authors' proposed myocardial defect model nuclear medicine physicians demonstrated no significant difference for the detection of the anterior wall defect; however, a greater accuracy for the detection of the inferior wall defect was observed without nonuniform AC than with it (P-value=0.0034). Medical physicists did not demonstrate any statistically significant difference in defect detection accuracy with or without nonuniform AC in the female phantom.

Radionuclide 131I-labeled multifunctional dendrimers for targeted SPECT imaging and radiotherapy of tumors

NASA Astrophysics Data System (ADS)

Zhu, Jingyi; Zhao, Lingzhou; Cheng, Yongjun; Xiong, Zhijuan; Tang, Yueqin; Shen, Mingwu; Zhao, Jinhua; Shi, Xiangyang

2015-10-01

We report the synthesis, characterization, and utilization of radioactive 131I-labeled multifunctional dendrimers for targeted single-photon emission computed tomography (SPECT) imaging and radiotherapy of tumors. In this study, amine-terminated poly(amidoamine) dendrimers of generation 5 (G5.NH2) were sequentially modified with 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO) and folic acid (FA) linked with polyethylene glycol (PEG), followed by acetylation modification of the dendrimer remaining surface amines and labeling of radioactive iodine-131 (131I). The generated multifunctional 131I-G5.NHAc-HPAO-PEG-FA dendrimers were characterized via different methods. We show that prior to 131I labeling, the G5.NHAc-HPAO-PEG-FA dendrimers conjugated with approximately 9.4 HPAO moieties per dendrimer are noncytotoxic at a concentration up to 20 μM and are able to target cancer cells overexpressing FA receptors (FAR), thanks to the modified FA ligands. In the presence of a phenol group, radioactive 131I is able to be efficiently labeled onto the dendrimer platform with good stability and high radiochemical purity, and render the platform with an ability for targeted SPECT imaging and radiotherapy of an FAR-overexpressing xenografted tumor model in vivo. The designed strategy to use the facile dendrimer nanotechnology may be extended to develop various radioactive theranostic nanoplatforms for targeted SPECT imaging and radiotherapy of different types of cancer.We report the synthesis, characterization, and utilization of radioactive 131I-labeled multifunctional dendrimers for targeted single-photon emission computed tomography (SPECT) imaging and radiotherapy of tumors. In this study, amine-terminated poly(amidoamine) dendrimers of generation 5 (G5.NH2) were sequentially modified with 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO) and folic acid (FA) linked with polyethylene glycol (PEG), followed by acetylation modification of the dendrimer remaining surface amines and labeling of radioactive iodine-131 (131I). The generated multifunctional 131I-G5.NHAc-HPAO-PEG-FA dendrimers were characterized via different methods. We show that prior to 131I labeling, the G5.NHAc-HPAO-PEG-FA dendrimers conjugated with approximately 9.4 HPAO moieties per dendrimer are noncytotoxic at a concentration up to 20 μM and are able to target cancer cells overexpressing FA receptors (FAR), thanks to the modified FA ligands. In the presence of a phenol group, radioactive 131I is able to be efficiently labeled onto the dendrimer platform with good stability and high radiochemical purity, and render the platform with an ability for targeted SPECT imaging and radiotherapy of an FAR-overexpressing xenografted tumor model in vivo. The designed strategy to use the facile dendrimer nanotechnology may be extended to develop various radioactive theranostic nanoplatforms for targeted SPECT imaging and radiotherapy of different types of cancer. Electronic supplementary information (ESI) available: Part of the experimental details and additional experimental results. See DOI: 10.1039/c5nr05585g

Regional lung ventilation and perfusion by electrical impedance tomography compared to single-photon emission computed tomography.

PubMed

Hentze, Benjamin; Muders, Thomas; Luepschen, Henning; Maripuu, Enn; Hedenstierna, Göran; Putensen, Christian; Walter, Marian; Leonhardt, Steffen

2018-06-20

Electrical impedance tomography (EIT) is a noninvasive imaging modality that allows real-time monitoring of regional lung ventilation ([Formula: see text]) in intensive care patients at bedside. However, for improved guidance of ventilation therapy it would be beneficial to obtain regional ventilation-to-perfusion ratio ([Formula: see text]) by EIT. In order to further explore the feasibility, we first evaluate a model-based approach, based on semi-negative matrix factorization and a gamma-variate model, to extract regional lung perfusion ([Formula: see text]) from EIT measurements. Subsequently, a combined validation of both [Formula: see text] and [Formula: see text] measured by EIT against single-photon emission computed tomography (SPECT) is performed on data acquired as part of a porcine animal trial. Four pigs were ventilated at two different levels of positive end-expiratory pressure (PEEP 0 and 15 cm H 2 O, respectively) in randomized order. Repeated injections of an EIT contrast agent (NaCl 10%) and simultaneous SPECT measurements of [Formula: see text] (81 m Kr gas) and [Formula: see text] (99 m Tc-labeled albumin) were performed. Both [Formula: see text] and [Formula: see text] from EIT and SPECT were compared by correlation analysis. Very strong (r 2   =  0.94 to 0.95) correlations were found for [Formula: see text] and [Formula: see text] in the dorsal-ventral direction at both PEEP levels. Moderate (r 2   =  0.36 to 0.46) and moderate to strong (r 2   =  0.61 to 0.82) correlations resulted for [Formula: see text] and [Formula: see text] in the right-left direction, respectively. The results of combined validation indicate that monitoring of [Formula: see text] and [Formula: see text] by EIT is possible. However, care should be taken when trying to quantify [Formula: see text] by EIT, as imaging artefacts and model bias may void necessary spatial matching.

(99m)Tc-3PRGD 2 SPECT/CT predicts the outcome of advanced nonsquamous non-small cell lung cancer receiving chemoradiotherapy plus bevacizumab.

PubMed

Ma, Qingjie; Min, Kaiyin; Wang, Ting; Chen, Bin; Wen, Qiang; Wang, Fan; Ji, Tiefeng; Gao, Shi

2015-07-01

Functional imaging can help clinicians assess the individual response of advanced nonsquamous non-small cell lung cancer (NSCLC) to chemoradiation therapy plus bevacizumab. Our purpose is to investigate the ability of (99m)Tc-3PRGD2 single photon emission computed tomography/computed tomography (SPECT/CT) in predicting the early response to treatment. Patients with advanced nonsquamous NSCLC diagnosed by histological or cytological examination were imaged with (99m)Tc-3PRGD2 SPECT/CT at 3 time points: 1-3 days before the start of treatment (SPECT1), 40 Gy radiotherapy with 2 cycles of chemotherapy plus bevacizumab (SPECT2) and 4 weeks after chemoradiotherapy plus bevacizumab (SPECT3). The images were evaluated semiquantitatively by measuring the tumor to non-tumor ratio (T/N) and calculating the percentage change in T/N ratio. Short-term outcome was assessed by the treatment response evaluation according to the Response Evaluation Criteria in Solid Tumors criteria as: complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD). Patients were divided two groups: responders (CR and PR) and nonresponders (SD and PD). To determine a threshold for percent reduction in T/N ratios, receiver-operating characteristic (ROC) curve analysis was used. Patients were grouped again based on the threshold of P1 (the change percentage from SPECT1 to SPECT2) and P2 (the change percentage from SPECT1 to SPECT3): P1 responders and P1 nonresponders; P2 responders and P2 nonresponders. Patients were followed up starting 4 weeks after completion of therapy and then every 3 months for the first 2 years and every 6 months after 2 years. OS of P1 responders, P1 nonresponders, P2 responders and P2 nonresponders was estimated and graphically illustrated using the Kaplan-Meier method and the log-rank test was used to test the null hypotheses of equal OS in subgroups of patients. A total of 28 patients completed all imaging and treatment. All primary lung tumors were well visualized on SPECT1. The mean T/N ratio of SPECT1 in responders and nonresponders was not statistically different (2.73 ± 0.59 vs. 2.59 ± 0.52, p > 0.05). At SPECT2 and SPECT3, the mean T/N ratios were both lower in the responders compared with the nonresponders and had statistical significance (p < 0.05). P1 and P2 in the responders was larger than the nonresponders with significant difference (P1: 34.18 ± 21.55 % vs. 9.02 ± 14.02 %, p < 0.05; P2: 53.02 ± 15.50 % vs. 7.74 ± 37.95 %, p < 0.05). The optimal threshold of P1 that can discriminate between P1 responders and P1 nonresponders was greater than 25.9 % reduction, and that of P2 that can discriminate between P2 responders and P2 nonresponders was 34.0 % reduction. The area under the ROC curve (AUC) of P1 and P2 for determining residual disease was 0.856 and 0.909, respectively; but there was no statistical significance between them (p > 0.05). There was a significant difference for OS between P1 responders and P1 nonresponders (p < 0.05), and also for OS between P2 responders and P2 nonresponders (p < 0.05). But there was no difference between the P1 responders and P2 responders (p > 0.05), or between the P1 nonresponders and P2 nonresponders (p > 0.05). A (99m)Tc-3PRGD2 SPECT/CT after two cycles of chemoradiotherapy plus bevacizumab can predict patients who will have a better response to treatment and survival.

Improving the convergence rate in affine registration of PET and SPECT brain images using histogram equalization.

PubMed

Salas-Gonzalez, D; Górriz, J M; Ramírez, J; Padilla, P; Illán, I A

2013-01-01

A procedure to improve the convergence rate for affine registration methods of medical brain images when the images differ greatly from the template is presented. The methodology is based on a histogram matching of the source images with respect to the reference brain template before proceeding with the affine registration. The preprocessed source brain images are spatially normalized to a template using a general affine model with 12 parameters. A sum of squared differences between the source images and the template is considered as objective function, and a Gauss-Newton optimization algorithm is used to find the minimum of the cost function. Using histogram equalization as a preprocessing step improves the convergence rate in the affine registration algorithm of brain images as we show in this work using SPECT and PET brain images.

Evaluation of reconstruction techniques in regional cerebral blood flow SPECT using trade-off plots: a Monte Carlo study.

PubMed

Olsson, Anna; Arlig, Asa; Carlsson, Gudrun Alm; Gustafsson, Agnetha

2007-09-01

The image quality of single photon emission computed tomography (SPECT) depends on the reconstruction algorithm used. The purpose of the present study was to evaluate parameters in ordered subset expectation maximization (OSEM) and to compare systematically with filtered back-projection (FBP) for reconstruction of regional cerebral blood flow (rCBF) SPECT, incorporating attenuation and scatter correction. The evaluation was based on the trade-off between contrast recovery and statistical noise using different sizes of subsets, number of iterations and filter parameters. Monte Carlo simulated SPECT studies of a digital human brain phantom were used. The contrast recovery was calculated as measured contrast divided by true contrast. Statistical noise in the reconstructed images was calculated as the coefficient of variation in pixel values. A constant contrast level was reached above 195 equivalent maximum likelihood expectation maximization iterations. The choice of subset size was not crucial as long as there were > or = 2 projections per subset. The OSEM reconstruction was found to give 5-14% higher contrast recovery than FBP for all clinically relevant noise levels in rCBF SPECT. The Butterworth filter, power 6, achieved the highest stable contrast recovery level at all clinically relevant noise levels. The cut-off frequency should be chosen according to the noise level accepted in the image. Trade-off plots are shown to be a practical way of deciding the number of iterations and subset size for the OSEM reconstruction and can be used for other examination types in nuclear medicine.

Ischaemic memory imaging using metabolic radiopharmaceuticals: overview of clinical settings and ongoing investigations.

PubMed

Yoshinaga, Keiichiro; Naya, Masanao; Shiga, Tohru; Suzuki, Eriko; Tamaki, Nagara

2014-02-01

"Ischaemic memory" is defined as a prolonged functional and/or biochemical alteration remaining after a particular episode of severe myocardial ischaemia. The biochemical alteration has been reported as metabolic stunning. Metabolic imaging has been used to detect the footprint left by previous ischaemic episodes evident due to delayed recovery of myocardial metabolism (persistent dominant glucose utilization with suppression of fatty acid oxidation). β-Methyl-p-[(123)I]iodophenylpentadecanoic acid (BMIPP) is a single-photon emission computed tomography (SPECT) radiotracer widely used for metabolic imaging in clinical settings in Japan. In patients with suspected coronary artery disease but no previous myocardial infarction, BMIPP has shown acceptable diagnostic accuracy. In particular, BMIPP plays an important role in the identification of prior ischaemic insult in patients arriving at emergency departments with acute chest pain syndrome. Recent data also show the usefulness of (123)I-BMIPP SPECT for predicting cardiovascular events in patients undergoing haemodialysis. Similarly, SPECT or PET imaging with (18)F-FDG injected during peak exercise or after exercise under fasting conditions shows an increase in FDG uptake in postischaemic areas. This article will overview the roles of ischaemic memory imaging both under established indications and in ongoing investigations.

Radiolabelled leucocyte scintigraphy versus conventional radiological imaging for the management of late, low-grade vascular prosthesis infections.

PubMed

Erba, P A; Leo, G; Sollini, M; Tascini, C; Boni, R; Berchiolli, R N; Menichetti, F; Ferrari, M; Lazzeri, E; Mariani, G

2014-02-01

In this study we evaluated the diagnostic performance of (99m)Tc-HMPAO-leucocyte ((99m)Tc-HMPAO-WBC) scintigraphy in a consecutive series of 55 patients (46 men and 9 women, mean age 71 ± 9 years, range 50 - 88 years) with a suspected late or a low-grade late vascular prosthesis infection (VPI), also comparing the diagnostic accuracy of WBC with that of other radiological imaging methods. All patients suspected of having VPI underwent clinical examination, blood tests, microbiology, US and CT, and were classified according to the Fitzgerald criteria. A final diagnosis of VPI was established in 47 of the 55 patients, with microbiological confirmation after surgical removal of the prosthesis in 36 of the 47. In the 11 patients with major contraindications to surgery, the final diagnosis was based on microbiology and clinical follow-up of at least 18 months. (99m)Tc-HMPAO-WBC planar, SPECT and SPECT/CT imaging identified VPI in 43 of 47 patients (20 of these also showed infection at extra-prosthetic sites). In the remaining eight patients without VPI, different sites of infections were found. The use of SPECT/CT images led to a significant reduction in the number of false-positive findings in 37% of patients (sensitivity and specificity 100 %, versus 85.1% and 62.5% for stand-alone SPECT). Sensitivity and specificity were 34% and 75% for US, 48.9% and 83.3% for CT, and 68.1% and 62.5% for the FitzGerald classification. Perioperative mortality was 5.5%, mid-term mortality 12%, and long-term mortality 27%. Survival rates were similar in patients treated with surgery and antimicrobial therapy compared to patients treated with antimicrobial therapy alone (61% versus 63%, respectively), while infection eradication at 12 months was significantly higher following surgery (83.3% versus 45.5%). (99m)Tc-HMPAO-WBC SPECT/CT is useful for detecting, localizing and defining the extent of graft infection in patients with late and low-grade late VPI with inconclusive radiological findings. (99m)Tc-HMPAO-WBC SPECT/CT might be used to optimize patient management.

The usefulness of the ivy sign on fluid-attenuated intensity recovery images in improved brain hemodynamic changes after superficial temporal artery-middle cerebral artery anastomosis in adult patients with moyamoya disease.

PubMed

Lee, Jung Keun; Yoon, Byul Hee; Chung, Seung Young; Park, Moon Sun; Kim, Seong Min; Lee, Do Sung

2013-10-01

MR perfusion and single photon emission computerized tomography (SPECT) are well known imaging studies to evaluate hemodynamic change between prior to and following superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease. But their side effects and invasiveness make discomfort to patients. We evaluated the ivy sign on MR fluid attenuated inversion recovery (FLAIR) images in adult patients with moyamoya disease and compared it with result of SPECT and MR perfusion images. We enrolled twelve patients (thirteen cases) who were diagnosed with moyamoya disease and underwent STA-MCA anastomosis at our medical institution during a period ranging from September of 2010 to December of 2012. The presence of the ivy sign on MR FLAIR images was classified as Negative (0), Minimal (1), and Positive (2). Regions were classified into four territories: the anterior cerebral artery (ACA), the anterior MCA, the posterior MCA and the posterior cerebral artery. Ivy signs on preoperative and postoperative MR FLAIR were improved (8 and 4 in the ACA regions, 13 and 4 in the anterior MCA regions and 19 and 9 in the posterior MCA regions). Like this result, the cerebrovascular reserve (CVR) on SPECT was significantly increased in the sum of CVR in same regions after STA-MCA anastomosis. After STA-MCA anastomosis, ivy signs were decreased in the cerebral hemisphere. As compared with conventional diagnostic modalities such as SPECT and MR perfusion images, the ivy sign on MR FLAIR is considered as a useful indicator in detecting brain hemodynamic changes between preoperatively and postoperatively in adult moyamoya patients.

The Usefulness of the Ivy Sign on Fluid-Attenuated Intensity Recovery Images in Improved Brain Hemodynamic Changes after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis in Adult Patients with Moyamoya Disease

PubMed Central

Lee, Jung Keun; Yoon, Byul Hee; Park, Moon Sun; Kim, Seong Min; Lee, Do Sung

2013-01-01

Objective MR perfusion and single photon emission computerized tomography (SPECT) are well known imaging studies to evaluate hemodynamic change between prior to and following superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease. But their side effects and invasiveness make discomfort to patients. We evaluated the ivy sign on MR fluid attenuated inversion recovery (FLAIR) images in adult patients with moyamoya disease and compared it with result of SPECT and MR perfusion images. Methods We enrolled twelve patients (thirteen cases) who were diagnosed with moyamoya disease and underwent STA-MCA anastomosis at our medical institution during a period ranging from September of 2010 to December of 2012. The presence of the ivy sign on MR FLAIR images was classified as Negative (0), Minimal (1), and Positive (2). Regions were classified into four territories: the anterior cerebral artery (ACA), the anterior MCA, the posterior MCA and the posterior cerebral artery. Results Ivy signs on preoperative and postoperative MR FLAIR were improved (8 and 4 in the ACA regions, 13 and 4 in the anterior MCA regions and 19 and 9 in the posterior MCA regions). Like this result, the cerebrovascular reserve (CVR) on SPECT was significantly increased in the sum of CVR in same regions after STA-MCA anastomosis. Conclusion After STA-MCA anastomosis, ivy signs were decreased in the cerebral hemisphere. As compared with conventional diagnostic modalities such as SPECT and MR perfusion images, the ivy sign on MR FLAIR is considered as a useful indicator in detecting brain hemodynamic changes between preoperatively and postoperatively in adult moyamoya patients. PMID:24294453

The use of combined single photon emission computed tomography and X-ray computed tomography to assess the fate of inhaled aerosol.

PubMed

Fleming, John; Conway, Joy; Majoral, Caroline; Tossici-Bolt, Livia; Katz, Ira; Caillibotte, Georges; Perchet, Diane; Pichelin, Marine; Muellinger, Bernhard; Martonen, Ted; Kroneberg, Philipp; Apiou-Sbirlea, Gabriela

2011-02-01

Gamma camera imaging is widely used to assess pulmonary aerosol deposition. Conventional planar imaging provides limited information on its regional distribution. In this study, single photon emission computed tomography (SPECT) was used to describe deposition in three dimensions (3D) and combined with X-ray computed tomography (CT) to relate this to lung anatomy. Its performance was compared to planar imaging. Ten SPECT/CT studies were performed on five healthy subjects following carefully controlled inhalation of radioaerosol from a nebulizer, using a variety of inhalation regimes. The 3D spatial distribution was assessed using a central-to-peripheral ratio (C/P) normalized to lung volume and for the right lung was compared to planar C/P analysis. The deposition by airway generation was calculated for each lung and the conducting airways deposition fraction compared to 24-h clearance. The 3D normalized C/P ratio correlated more closely with 24-h clearance than the 2D ratio for the right lung [coefficient of variation (COV), 9% compared to 15% p < 0.05]. Analysis of regional distribution was possible for both lungs in 3D but not in 2D due to overlap of the stomach on the left lung. The mean conducting airways deposition fraction from SPECT for both lungs was not significantly different from 24-h clearance (COV 18%). Both spatial and generational measures of central deposition were significantly higher for the left than for the right lung. Combined SPECT/CT enabled improved analysis of aerosol deposition from gamma camera imaging compared to planar imaging. 3D radionuclide imaging combined with anatomical information from CT and computer analysis is a useful approach for applications requiring regional information on deposition.

Determination of Three-Dimensional Left Ventricle Motion to Analyze Ventricular Dyssyncrony in SPECT Images

NASA Astrophysics Data System (ADS)

Rebelo, Marina de Sá; Aarre, Ann Kirstine Hummelgaard; Clemmesen, Karen-Louise; Brandão, Simone Cristina Soares; Giorgi, Maria Clementina; Meneghetti, José Cláudio; Gutierrez, Marco Antonio

2009-12-01

A method to compute three-dimension (3D) left ventricle (LV) motion and its color coded visualization scheme for the qualitative analysis in SPECT images is proposed. It is used to investigate some aspects of Cardiac Resynchronization Therapy (CRT). The method was applied to 3D gated-SPECT images sets from normal subjects and patients with severe Idiopathic Heart Failure, before and after CRT. Color coded visualization maps representing the LV regional motion showed significant difference between patients and normal subjects. Moreover, they indicated a difference between the two groups. Numerical results of regional mean values representing the intensity and direction of movement in radial direction are presented. A difference of one order of magnitude in the intensity of the movement on patients in relation to the normal subjects was observed. Quantitative and qualitative parameters gave good indications of potential application of the technique to diagnosis and follow up of patients submitted to CRT.

Evaluation of 111In-labeled EPep and FibPep as tracers for fibrin SPECT imaging.

PubMed

Starmans, Lucas W E; van Duijnhoven, Sander M J; Rossin, Raffaella; Berben, Monique; Aime, Silvio; Daemen, Mat J A P; Nicolay, Klaas; Grüll, Holger

2013-11-04

Fibrin targeting is an attractive strategy for nuclear imaging of thrombosis, atherosclerosis and cancer. Recently, FibPep, an (111)In-labeled fibrin-binding peptide, was established as a tracer for fibrin SPECT imaging and was reported to allow sensitive detection of minute thrombi in mice using SPECT. In this study, we developed EPep, a novel (111)In-labeled fibrin-binding peptide containing the fibrin-binding domain of the clinically verified EP-2104R peptide, and sought to compare the potential of EPep and FibPep as tracers for fibrin SPECT imaging. In vitro, both EPep and FibPep showed high stability in serum, but were less stable in liver and kidney homogenate assays. Both peptide probes displayed comparable affinities toward human and mouse derived fibrin (Kd ≈ 1 μM), and similarly to FibPep, EPep showed fast blood clearance, low nontarget uptake and high thrombus uptake (6.8 ± 1.2% ID g(-1)) in a mouse carotid artery thrombosis model. Furthermore, EPep showed a similar affinity toward rat derived fibrin (Kd ≈ 1 μM), displayed high thrombus uptake in a rat carotid artery thrombosis model (0.74 ± 0.39% ID g(-1)), and allowed sensitive detection of thrombosis in rats using SPECT. In contrast, FibPep displayed a significantly lower affinity toward rat derived fibrin (Kd ≈ 14 μM) and low uptake in rat thrombi (0.06 ± 0.02% ID g(-1)) and did not allow clear visualization of carotid artery thrombosis in rats using SPECT. These results were confirmed ex vivo by autoradiography, which showed a 7-fold higher ratio of activity in the thrombus over the contralateral carotid artery for EPep in comparison to FibPep. These findings suggest that the FibPep binding fibrin epitope is not fully homologous between humans and rats, and that preclinical rat models of disease should not be employed to gauge the clinical potential of FibPep. In conclusion, both peptides showed approximately similar metabolic stability and affinity toward human and mouse derived fibrin, and displayed high thrombus uptake in a mouse carotid artery thrombosis model. Therefore, both EPep and FibPep are promising fibrin targeted tracers for translation into clinical settings to serve as novel tools for molecular imaging of fibrin.

Development of a Novel SPECT Tracer to Image c-Met Expression in Non-Small Cell Lung Cancer in a Human Tumor Xenograft.

PubMed

Han, Zhaoguo; Xiao, Yadi; Wang, Kai; Yan, Ji; Xiao, Zunyu; Fang, Fang; Jin, Zhongnan; Liu, Yang; Sun, Xilin; Shen, Baozhong

2018-05-18

Rationale: Elevated expression of the c-Met receptor plays a crucial role in cancers. In non-small cell lung cancer (NSCLC), aberrant activation of c-Met signaling pathway contributes to tumorigenesis and cancer progression, and may mediate acquired resistance to epidermal growth factor receptor-targeted therapy. c-Met is therefore emerging as a promising therapeutic target for treating NSCLC, and the methods for noninvasive in vivo assessment of c-Met expression will improve NSCLC treatment and diagnosis. Methods: A new peptide-based (cMBP) radiotracer targeting c-Met, 99m Tc-hydrazine nicotinamide (HYNIC)-cMBP, was developed for single photon emission computed tomography (SPECT) imaging. Cell uptake assays were performed on two NSCLC cell lines with different c-Met expression: H1993 (high expression) and H1299 (no expression). In vivo tumor specificity was assessed by SPECT imaging in tumor-bearing mice at 0.5, 1, 2 and 4 h after injection of the probe. Blocking assays, biodistribution and autoradiography were also conducted to determine probe specificity. Results: 99m Tc-HYNIC-cMBP was prepared with high efficiency and showed higher uptake in H1993 cells than H1299 cells. Biodistribution and autoradiography also showed significantly higher accumulation of 99m Tc-HYNIC-cMBP in H1993 tumors than H1299 (H1993: 4.74±1.43 %ID/g and H1299: 1.00±0.37 %ID/g at 0.5h, p<0.05). H1993 tumors were clearly visualized at 0.5h in SPECT images, whereas H1299 tumors were not observed at any time. Specificity of 99m Tc-HYNIC-cMBP to c-Met was demonstrated by competitive block with excess un-radiolabeled peptide. Conclusion: We developed a novel SPECT tracer, 99m Tc-HYNIC-cMBP, for c-Met-targeted imaging in NSCLC that specifically bound to c-Met with favorable pharmacokinetics in vitro and in vivo. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Imaging in primary hyperparathyroidism: focus on the evidence-based diagnostic performance of different methods.

PubMed

Treglia, Giorgio; Trimboli, Pierpaolo; Huellner, Martin; Giovanella, Luca

2018-06-01

Primary hyperparathyroidism (PHPT) is a common endocrine disorder usually due to hyperfunctioning parathyroid glands (HP). Surgical removal of HP is the main treatment in PHPT, particularly in symptomatic patients. The correct detection and localization of HP is challenging and crucial as it may guide surgical treatment in patients with PHPT. To date, different imaging methods have been used to detect and localize HP in patients with PHPT including radiology, nuclear medicine and hybrid techniques. This review was focused to describe the diagnostic performance of several imaging methods used in detecting HP in patients with PHPT. We have summarized the diagnostic performance of different imaging methods used in detecting HP in patients with PHPT taking into account recent evidence-based articles published in the literature. To this regard, findings of recently published meta-analyses on the diagnostic accuracy of imaging methods in PHPT were reported. Furthermore, a suggested imaging strategy taking into account the diagnostic performance and further consideration has been described. Cervical ultrasound (US) and parathyroid scintigraphy using 99mTc-MIBI are the most commonly employed first-line investigations in patients with PHPT, with many institutions using both methods in combination. The diagnostic performance of US and planar 99mTc-MIBI scintigraphy seems to be similar. The use of tomographic imaging (SPECT and SPECT/CT) increases the detection rate of HP compared to planar 99mTc-MIBI scintigraphy. Whereas traditional computed tomography (CT) has limited usefulness in PHPT, four dimensional CT (4D-CT) has similar diagnostic performance compared to tomographic parathyroid scintigraphy but a higher radiation dose. Although initial encouraging results, to date there is insufficient evidence to recommend the routine use of MRI or positron emission tomography (PET) with several radiopharmaceuticals in patients with PHPT. However, they could be useful alternatives in cases with negative or discordant findings at first-line imaging methods. Patients with PHPT who are candidates for parathyroidectomy should be referred to an expert clinician to decide which imaging studies to perform based on regional imaging capabilities. The imaging techniques with higher diagnostic performance in detecting and localizing HP seems to be 99mTc-MIBI SPECT/CT and 4D-CT. Taking into account several data beyond the diagnostic performance, the combination of cervical US performed by an experienced parathyroid sonographer and 99mTc-MIBI SPECT or SPECT//CT seems to be an optimal first-line strategy in the preoperative planning of patients with PHPT.

Usefulness of parametric renal clearance images in the assessment of basic risk factors for renalnal clearance images in the assessment of basic risk factors for renal scarring in children with recurrent urinary tract infections.

PubMed

Pietrzak-Stelasiak, Ewa; Bieńkiewicz, Małgorzata; Woźnicki, Wojciech; Bubińska, Krystyna; Kowalewska-Pietrzak, Magdalena; Płachcińska, Anna; Kuśmierek, Jacek

2017-01-01

Clinically confirmed incidents of acute pyelonephritis (APN) following recurrent infections of urinary tract (UTI) form basic risk factors for renal scarring in children. Vesico-uretheral reflux (VUR) of higher grade is additional risk factor for this scarring. Opinions on diagnostic value of summed sequential images of renal uptake phase (SUM) of dynamic renal scintigraphy in detection of renal scars are diverse. However, several publications point to higher diagnostic efficacy of clearance parametric images (PAR) generated from this study. To establish a clinical value of parametric renal clearance images in detection of renal scarring. A prospective study was performed in a group of 91 children at the age of 4 to 18 years with recurrent UTI. Clinically documented incidents of APN were noted in 32 children: in 8 cases - one and in the remaining 24 - 2 to 5 (mean 3) incidents. In the remaining 59 patients only infections of the lower part of urinary tract were diagnosed. Static renal 99mTc-DMSA SPECT study and after 2-4 days dynamic renal studies (99mTc-EC) were performed in every patient not earlier than 6 months after the last documented incident of UTI. PAR images generated from a dynamic study by in-house developed software and SUM images were compared with a gold standard SPECT study. Percentages of children with detected renal scar(s) with SPECT and PAR methods amounted to 55% and 54%, respectively and were statistically significantly higher (p < 0.0001) than with SUM method - 31%. Scars in children with history of APN detected with SPECT and PAR methods were significantly more frequent than with infections of only lower part of urinary tract (72% vs. 46%; p = 0.017 and 69% vs. 46%; p = 0.036, respectively). A SUM method did not reveal statistically significant differences between frequencies of detection of scars in groups specified above - 38% vs. 27% (p = 0.31). Both SPECT and PAR methods showed also that frequencies of occurrence of renal scars in children with higher grades of VUR were higher than without or with lower grades of VUR: 79% vs. 50% (p = 0.048) and 79% vs. 49% (p = 0.04). A SUM method did not reveal higher frequency of renal scars in children with high VUR grades: 36% vs. 30% (p = 0.44). Results obtained with PAR and SPECT methods were similar. An advantage of PAR over SUM images obtained from a dynamic renal scintigraphy in detection of renal scars in children with UTI was confirmed.

Fast GPU-based Monte Carlo code for SPECT/CT reconstructions generates improved 177Lu images.

PubMed

Rydén, T; Heydorn Lagerlöf, J; Hemmingsson, J; Marin, I; Svensson, J; Båth, M; Gjertsson, P; Bernhardt, P

2018-01-04

Full Monte Carlo (MC)-based SPECT reconstructions have a strong potential for correcting for image degrading factors, but the reconstruction times are long. The objective of this study was to develop a highly parallel Monte Carlo code for fast, ordered subset expectation maximum (OSEM) reconstructions of SPECT/CT images. The MC code was written in the Compute Unified Device Architecture language for a computer with four graphics processing units (GPUs) (GeForce GTX Titan X, Nvidia, USA). This enabled simulations of parallel photon emissions from the voxels matrix (128 3 or 256 3 ). Each computed tomography (CT) number was converted to attenuation coefficients for photo absorption, coherent scattering, and incoherent scattering. For photon scattering, the deflection angle was determined by the differential scattering cross sections. An angular response function was developed and used to model the accepted angles for photon interaction with the crystal, and a detector scattering kernel was used for modeling the photon scattering in the detector. Predefined energy and spatial resolution kernels for the crystal were used. The MC code was implemented in the OSEM reconstruction of clinical and phantom 177 Lu SPECT/CT images. The Jaszczak image quality phantom was used to evaluate the performance of the MC reconstruction in comparison with attenuated corrected (AC) OSEM reconstructions and attenuated corrected OSEM reconstructions with resolution recovery corrections (RRC). The performance of the MC code was 3200 million photons/s. The required number of photons emitted per voxel to obtain a sufficiently low noise level in the simulated image was 200 for a 128 3 voxel matrix. With this number of emitted photons/voxel, the MC-based OSEM reconstruction with ten subsets was performed within 20 s/iteration. The images converged after around six iterations. Therefore, the reconstruction time was around 3 min. The activity recovery for the spheres in the Jaszczak phantom was clearly improved with MC-based OSEM reconstruction, e.g., the activity recovery was 88% for the largest sphere, while it was 66% for AC-OSEM and 79% for RRC-OSEM. The GPU-based MC code generated an MC-based SPECT/CT reconstruction within a few minutes, and reconstructed patient images of 177 Lu-DOTATATE treatments revealed clearly improved resolution and contrast.

Is prophylactic embolization of the hepatic falciform artery needed before radioembolization in patients with 99mTc-MAA accumulation in the anterior abdominal wall?

PubMed

Ahmadzadehfar, Hojjat; Möhlenbruch, Markus; Sabet, Amir; Meyer, Carsten; Muckle, Marianne; Haslerud, Torjan; Wilhelm, Kai; Schild, Hans Heinz; Biersack, Hans Jürgen; Ezziddin, Samer

2011-08-01

While influx of chemoembolic agents into the hepatic falciform artery (HFA) from the hepatic artery can cause supraumbilical skin rash, epigastric pain and even skin necrosis, the significance of a patent HFA in patients undergoing radioembolization is not completely clear. Furthermore, the presence of tracer in the anterior abdominal wall seen in (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) images, which is generally performed prior to radioembolization, has been described as a sign of a patent HFA. The aim of this retrospective study was to evaluate the incidence and consequences of (99m)Tc-MAA accumulation in the anterior abdominal wall, indicating a patent HFA, in patients undergoing radioembolization of liver tumours. A total of 224 diagnostic hepatic angiograms combined with (99m)Tc-MAA SPECT/CT were acquired in 192 patients with different types of cancer, of whom 142 were treated with a total of 214 radioembolization procedures. All patients received a whole-body scan, and planar and SPECT/CT scans of the abdomen. Only patients with extrahepatic (99m)Tc-MAA accumulation in the anterior abdominal wall were included in this study. Posttreatment bremsstrahlung SPECT/CT and follow-up results for at least 3 months served as reference standards. Tracer accumulation in the anterior abdominal wall was present in pretreatment (99m)Tc-MAA SPECT/CT images of 18 patients (9.3%). The HFA was found and embolized by radiologists before treatment in one patient. In the remaining patients radioembolization was performed without any modification in the treatment plan despite the previously mentioned extrahepatic accumulation. Only one patient experienced abdominal muscle pain above the navel, which started 24 h after treatment and lasted for 48 h without any skin changes. The remaining patients did not experience any relevant side effects during the follow-up period. Side effects after radioembolization in patients with tracer accumulation in the anterior abdominal wall on (99m)Tc-MAA scans indicating a patent HFA are neither common nor severe. Thus, there is no absolute need for prophylactic embolization of the HFA or modification of the treatment plan if the HFA is not detectable on angiography.

A SPECT Scanner for Rodent Imaging Based on Small-Area Gamma Cameras

NASA Astrophysics Data System (ADS)

Lage, Eduardo; Villena, José L.; Tapias, Gustavo; Martinez, Naira P.; Soto-Montenegro, Maria L.; Abella, Mónica; Sisniega, Alejandro; Pino, Francisco; Ros, Domènec; Pavia, Javier; Desco, Manuel; Vaquero, Juan J.

2010-10-01

We developed a cost-effective SPECT scanner prototype (rSPECT) for in vivo imaging of rodents based on small-area gamma cameras. Each detector consists of a position-sensitive photomultiplier tube (PS-PMT) coupled to a 30 x 30 Nal(Tl) scintillator array and electronics attached to the PS-PMT sockets for adapting the detector signals to an in-house developed data acquisition system. The detector components are enclosed in a lead-shielded case with a receptacle to insert the collimators. System performance was assessed using 99mTc for a high-resolution parallel-hole collimator, and for a 0.75-mm pinhole collimator with a 60° aperture angle and a 42-mm collimator length. The energy resolution is about 10.7% of the photopeak energy. The overall system sensitivity is about 3 cps/μCi/detector and planar spatial resolution ranges from 2.4 mm at 1 cm source-to-collimator distance to 4.1 mm at 4.5 cm with parallel-hole collimators. With pinhole collimators planar spatial resolution ranges from 1.2 mm at 1 cm source-to-collimator distance to 2.4 mm at 4.5 cm; sensitivity at these distances ranges from 2.8 to 0.5 cps/μCi/detector. Tomographic hot-rod phantom images are presented together with images of bone, myocardium and brain of living rodents to demonstrate the feasibility of preclinical small-animal studies with the rSPECT.

Addition of atropine to submaximal exercise stress testing in patients evaluated for suspected ischaemia with SPECT imaging: a randomized, placebo-controlled trial.

PubMed

Manganelli, Fiore; Spadafora, Marco; Varrella, Paola; Peluso, Giuseppina; Sauro, Rosario; Di Lorenzo, Emilio; Rosato, Giuseppe; Daniele, Stefania; Cuocolo, Alberto

2011-02-01

To evaluate the effects of the addition of atropine to exercise testing in patients who failed to achieve their target heart rate (HR) during stress myocardial perfusion imaging with single-photon emission computed tomography (SPECT). The study was a prospective, randomized, placebo-controlled design. Patients with suspected or known coronary artery disease who failed to achieve a target HR (≥85% of maximal predicted HR) during exercise SPECT imaging were randomized to receive intravenous atropine (n=100) or placebo (n=101). The two groups of patients did not differ with respect to demographic or clinical characteristics. A higher proportion of patients in the atropine group achieved the target HR compared to the placebo group (60% versus 3%, p<0.0001). SPECT imaging was abnormal in a higher proportion of patients in the atropine group as compared to the placebo group (57% versus 42%, p<0.05). Stress-induced myocardial ischaemia was present in more patients in the atropine group as compared to placebo (47% versus 29%, p<0.01). In both groups of patients, no major side effects occurred. The addition of atropine at the end of exercise testing is more effective than placebo in raising HR to adequate levels, without additional risks of complications. The use of atropine in patients who initially failed to achieve their maximal predicted HR is associated with a higher probability of achieving a diagnostic myocardial perfusion study.

Anatomy guided automated SPECT renal seed point estimation

NASA Astrophysics Data System (ADS)

Dwivedi, Shekhar; Kumar, Sailendra

2010-04-01

Quantification of SPECT(Single Photon Emission Computed Tomography) images can be more accurate if correct segmentation of region of interest (ROI) is achieved. Segmenting ROI from SPECT images is challenging due to poor image resolution. SPECT is utilized to study the kidney function, though the challenge involved is to accurately locate the kidneys and bladder for analysis. This paper presents an automated method for generating seed point location of both kidneys using anatomical location of kidneys and bladder. The motivation for this work is based on the premise that the anatomical location of the bladder relative to the kidneys will not differ much. A model is generated based on manual segmentation of the bladder and both the kidneys on 10 patient datasets (including sum and max images). Centroid is estimated for manually segmented bladder and kidneys. Relatively easier bladder segmentation is followed by feeding bladder centroid coordinates into the model to generate seed point for kidneys. Percentage error observed in centroid coordinates of organs from ground truth to estimated values from our approach are acceptable. Percentage error of approximately 1%, 6% and 2% is observed in X coordinates and approximately 2%, 5% and 8% is observed in Y coordinates of bladder, left kidney and right kidney respectively. Using a regression model and the location of the bladder, the ROI generation for kidneys is facilitated. The model based seed point estimation will enhance the robustness of kidney ROI estimation for noisy cases.

Comparison of Gated SPECT Myocardial Perfusion Imaging with Echocardiography for the Measurement of Left Ventricular Volumes and Ejection Fraction in Patients With Severe Heart Failure

PubMed Central

Shojaeifard, Maryam; Ghaedian, Tahereh; Yaghoobi, Nahid; Malek, Hadi; Firoozabadi, Hasan; Bitarafan-Rajabi, Ahmad; Haghjoo, Majid; Amin, Ahmad; Azizian, Nasrin; Rastgou, Feridoon

2015-01-01

Background: Gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is known as a feasible tool for the measurement of left ventricular ejection fraction (EF) and volumes, which are of great importance in the management and follow-up of patients with coronary artery diseases. However, considering the technical shortcomings of SPECT in the presence of perfusion defect, the accuracy of this method in heart failure patients is still controversial. Objectives: The aim of the present study was to compare the results from gated SPECT MPI with those from echocardiography in heart failure patients to compare echocardiographically-derived left ventricular dimension and function data to those from gated SPECT MPI in heart failure patients. Patients and Methods: Forty-one patients with severely reduced left ventricular systolic function (EF ≤ 35%) who were referred for gated SPECT MPI were prospectively enrolled. Quantification of EF, end-diastolic volume (EDV), and end-systolic volume (ESV) was performed by using quantitative gated spect (QGS) (QGS, version 0.4, May 2009) and emory cardiac toolbox (ECTb) (ECTb, revision 1.0, copyright 2007) software packages. EF, EDV, and ESV were also measured with two-dimensional echocardiography within 3 days after MPI. Results: A good correlation was found between echocardiographically-derived EF, EDV, and ESV and the values derived using QGS (r = 0.67, r = 0.78, and r = 0.80 for EF, EDV, and ESV, respectively; P < 0.001) and ECTb (r = 0.68, 0.79, and r = 0.80 for EF, EDV, and ESV, respectively; P < 0.001). However, Bland-Altman plots indicated significantly different mean values for EF, 11.4 and 20.9 using QGS and ECTb, respectively, as compared with echocardiography. ECTb-derived EDV was also significantly higher than the EDV measured with echocardiography and QGS. The highest correlation between echocardiography and gated SPECT MPI was found for mean values of ESV different. Conclusions: Gated SPECT MPI has a good correlation with echocardiography for the measurement of left ventricular EF, EDV, and ESV in patients with severe heart failure. However, the absolute values of these functional parameters from echocardiography and gated SPECT MPI measured with different software packages should not be used interchangeably. PMID:26889455

Validation of gated blood-pool SPECT cardiac measurements tested using a biventricular dynamic physical phantom.

PubMed

De Bondt, Pieter; Nichols, Kenneth; Vandenberghe, Stijn; Segers, Patrick; De Winter, Olivier; Van de Wiele, Christophe; Verdonck, Pascal; Shazad, Arsalan; Shoyeb, Abu H; De Sutter, Johan

2003-06-01

We have developed a biventricular dynamic physical cardiac phantom to test gated blood-pool (GBP) SPECT image-processing algorithms. Such phantoms provide absolute values against which to assess accuracy of both right and left computed ventricular volume and ejection fraction (EF) measurements. Two silicon-rubber chambers driven by 2 piston pumps simulated crescent-shaped right ventricles wrapped partway around ellopsoid left ventricles. Twenty experiments were performed at Ghent University, for which right and left ventricular true volume and EF ranges were 65-275 mL and 55-165 mL and 7%-49% and 12%-69%, respectively. Resulting 64 x 64 simulated GBP SPECT images acquired at 16 frames per R-R interval were sent to Columbia University, where 2 observers analyzed images independently of each other, without knowledge of true values. Algorithms automatically segmented right ventricular activity volumetrically from left ventricular activity. Automated valve planes, midventricular planes, and segmentation regions were presented to observers, who accepted these choices or modified them as necessary. One observer repeated measurements >1 mo later without reference to previous determinations. Linear correlation coefficients (r) of the mean of the 3 GBP SPECT observations versus true values for right and left ventricles were 0.80 and 0.94 for EF and 0.94 and 0.95 for volumes, respectively. Correlations for right and left ventricles were 0.97 and 0.97 for EF and 0.96 and 0.89 for volumes, respectively, for interobserver agreement and 0.97 and 0.98 for EF and 0.96 and 0.90 for volumes, respectively, for intraobserver agreement. No trends were detected, though volumes and right ventricular EFs were significantly higher than true values. Overall, GBP SPECT measurements correlated strongly with true values. The phantom evaluated shows considerable promise for helping to guide algorithm developments for improved GBP SPECT accuracy.

Early detection of radiation-induced heart disease using (99m)Tc-MIBI SPECT gated myocardial perfusion imaging in patients with oesophageal cancer during radiotherapy.

PubMed

Zhang, Peng; Hu, Xudong; Yue, Jinbo; Meng, Xue; Han, Dali; Sun, Xindong; Yang, Guoren; Wang, Shijiang; Wang, Xiaohui; Yu, Jinming

2015-05-01

The primary aim of this prospective study was to investigate the value of (99m)Tc-methoxyisobutylisonitrile (MIBI) single photon emission computed tomography (SPECT) gated myocardial perfusion imaging (GMPI) in the detection of radiation-induced heart disease (RIHD) as early as during radiotherapy (RT) for oesophageal cancer (EC). The second aim was to analyse the correlation between cardiac toxicity and the dose-volume factors. The (99m)Tc-MIBI SPECT GMPI was performed both pre-RT and during RT (40Gray). The results of the SPECT were quantitatively analysed with QGS/QPS software and read by two experienced nuclear medicine physicians. The correlation between the changes in the SPECT parameters and the RT dosimetric data was analysed. Eighteen patients with locally advanced EC were enrolled in the study. Compared with the baseline, the imaging during RT showed not only significant decreases in the wall motion (WM) (1/20 segments), wall thickening (WT) (2/20 segments), end-diastolic perfusion (EDP) (5/20 segments) and end-systolic perfusion (ESP) (8/20 segments) (p<0.05) but also a significant increase in the heart rate (74.63±7.79 vs 81.49±9.90, p=0.036). New myocardial perfusion defects were observed in 8 of the 18 patients. The V37-V40 was significantly higher (p<0.05) in the patients with the new perfusion defects during RT than in the patients who did not exhibit these defects. Radiotherapy for EC induces cardiac damage from an early stage. (99m)Tc-MIBI SPECT GMPI can detect the occurrence of cardiac impairment during RT. The WM, WT, EDP and ESP may be valuable as early indicators of RIHD. The percentage of the heart volume that receives a high dose is an important factor that is correlated with RIHD. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Fluorescence-enhanced optical tomography and nuclear imaging system for small animals

NASA Astrophysics Data System (ADS)

Tan, I.-Chih; Lu, Yujie; Darne, Chinmay; Rasmussen, John C.; Zhu, Banghe; Azhdarinia, Ali; Yan, Shikui; Smith, Anne M.; Sevick-Muraca, Eva M.

2012-03-01

Near-infrared (NIR) fluorescence is an alternative modality for molecular imaging that has been demonstrated in animals and recently in humans. Fluorescence-enhanced optical tomography (FEOT) using continuous wave or frequency domain photon migration techniques could be used to provide quantitative molecular imaging in vivo if it could be validated against "gold-standard," nuclear imaging modalities, using dual-labeled imaging agents. Unfortunately, developed FEOT systems are not suitable for incorporation with CT/PET/SPECT scanners because they utilize benchtop devices and require a large footprint. In this work, we developed a miniaturized fluorescence imaging system installed in the gantry of the Siemens Inveon PET/CT scanner to enable NIR transillumination measurements. The system consists of a CCD camera equipped with NIR sensitive intensifier, a diode laser controlled by a single board compact controller, a 2-axis galvanometer, and RF circuit modules for homodyne detection of the phase and amplitude of fluorescence signals. The performance of the FEOT system was tested and characterized. A mouse-shaped solid phantom of uniform optical properties with a fluorescent inclusion was scanned using CT, and NIR fluorescence images at several projections were collected. The method of high-order approximation to the radioactive transfer equation was then used to reconstruct the optical images. Dual-labeled agents were also used on a tumor bearing mouse to validate the results of the FEOT against PET/CT image. The results showed that the location of the fluorophore obtained from the FEOT matches the location of tumor obtained from the PET/CT images. Besides validation of FEOT, this hybrid system could allow multimodal molecular imaging (FEOT/PET/CT) for small animal imaging.

Double match of 18F-fluorodeoxyglucose-PET and iomazenil-SPECT improves outcomes of focus resection surgery.

PubMed

Fujimoto, Ayataka; Okanishi, Tohru; Kanai, Sotaro; Sato, Keishiro; Itamura, Shinji; Baba, Shimpei; Nishimura, Mitsuyo; Masui, Takayuki; Enoki, Hideo

2018-06-01

When the results of electroencephalography (EEG), magnetic resonance imaging (MRI), and seizure semiology are discordant or no structural lesion is evident on MRI, single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are important examinations for lateralization or localization of epileptic regions. We hypothesized that the concordance between interictal 2-[ 18 F]fluoro-2-deoxy-D-glucose ( 18 FDG)-PET and iomazenil (IMZ)-SPECT could suggest the epileptogenic lobe in patients with non-lesional findings on MRI. Fifty-nine patients (31 females, 28 males; mean age, 29 years; median age, 27 years; range, 7-56 years) underwent subdural electrode implantation followed by focus resection. All patients underwent 18 FDG-PET, IMZ-SPECT, and focus resection surgery. Follow-up was continued for ≥ 2 years. We evaluated surgical outcomes as seizure-free or not and analyzed correlations between outcomes and concordances of low-uptake lobes on PET, SPECT, or both PET and SPECT to the resection lobes. We used uni- and multivariate logistic regression analyses. In univariate analyses, all three concordances correlated significantly with seizure-free outcomes (PET, p = 0.017; SPECT, p = 0.030; both PET and SPECT, p = 0.006). In multivariate analysis, concordance between resection and low-uptake lobes in both PET and SPECT correlated significantly with seizure-free outcomes (p = 0.004). The odds ratio was 6.0. Concordance between interictal 18 FDG-PET and IMZ-SPECT suggested that the epileptogenic lobe is six times better than each examination alone among patients with non-lesional findings on MRI. IMZ-SPECT and 18 FDG-PET are complementary examinations in the assessment of localization-related epilepsy.

Studying Spatial Resolution of CZT Detectors Using Sub-Pixel Positioning for SPECT

NASA Astrophysics Data System (ADS)

Montémont, Guillaume; Lux, Silvère; Monnet, Olivier; Stanchina, Sylvain; Verger, Loïck

2014-10-01

CZT detectors are the basic building block of a variety of new SPECT systems. Their modularity allows adapting system architecture to specific applications such as cardiac, breast, brain or small animal imaging. In semiconductors, a high number of electron-hole pairs is produced by a single interaction. This direct conversion process allows better energy and spatial resolutions than usual scintillation detectors based on NaI(Tl). However, it remains often unclear if SPECT imaging can really benefit of that performance gain. We investigate the system performance of a detection module, which is based on 5 mm thick CZT with a segmented anode having a 2.5 mm pitch by simulation and experimentation. This pitch allows an easy assembly of the crystal on the readout board and limits the space occupied by electronics without significantly degrading energy and spatial resolution.

An incidentally found inflamed uterine myoma causing low abdominal pain, using Tc-99m-tektrotyd single photon emission computed tomography-CT hybrid imaging.

PubMed

Zandieh, Shahin; Schütz, Matthias; Bernt, Reinhard; Zwerina, Jochen; Haller, Joerg

2013-01-01

We report the case of a 50-year-old woman presented with a history of right hemicolectomy due to an ileocecal neuroendocrine tumor and left breast metastasis. Owing to a slightly elevated chromogranin A-level and lower abdominal pain, single photon emission computed tomography-computer tomography (SPECT-CT) was performed. There were no signs of recurrence on the SPECT-CT scan, but the patient was incidentally found to have an inflamed intramural myoma. We believe that the slightly elevated chromogranin A-level was caused by the hypertension that the patient presented. In the clinical context, this is a report of an inflamed uterine myoma seen as a false positive result detected by TC-99m-Tc-EDDA/HYNIC-Tyr3-Octreotide (Tektrotyd) SPECT-CT hybrid imaging.

SPECT in patients with cortical visual loss.

PubMed

Silverman, I E; Galetta, S L; Gray, L G; Moster, M; Atlas, S W; Maurer, A H; Alavi, A

1993-09-01

Single-photon emission computed tomography (SPECT) with 99mTc-hexamethylpropyleneamine oxime (HMPAO) was used to investigate changes in cerebral blood flow in seven patients with cortical visual impairment. Traumatic brain injury (TBI) was the cause of cortical damage in two patients, cerebral ischemia in two patients and carbon monoxide (CO) poisoning, status epilepticus and Alzheimer's Disease (AD) each in three separate patients. The SPECT scans of the seven patients were compared to T2-weighted magnetic resonance image (MRI) scans of the brain to determine the correlation between functional and anatomical findings. In six of the seven patients, the qualitative interpretation of the SPECT studies supported the clinical findings (i.e., the visual field defect) by revealing altered regional cerebral blood flow (rCBF) in the appropriate regions of the visual pathway. MR scans in all of the patients, on the other hand, were either normal or disclosed smaller lesions than those detected by SPECT. We conclude that SPECT may reveal altered rCBF in patients with cortical visual impairment of various etiologies, even when MRI studies are normal or nondiagnostic.

An automatic alignment tool to improve repeatability of left ventricular function and dyssynchrony parameters in serial gated myocardial perfusion SPECT studies

PubMed Central

Zhou, Yanli; Faber, Tracy L.; Patel, Zenic; Folks, Russell D.; Cheung, Alice A.; Garcia, Ernest V.; Soman, Prem; Li, Dianfu; Cao, Kejiang; Chen, Ji

2013-01-01

Objective Left ventricular (LV) function and dyssynchrony parameters measured from serial gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) using blinded processing had a poorer repeatability than when manual side-by-side processing was used. The objective of this study was to validate whether an automatic alignment tool can reduce the variability of LV function and dyssynchrony parameters in serial gated SPECT MPI. Methods Thirty patients who had undergone serial gated SPECT MPI were prospectively enrolled in this study. Thirty minutes after the first acquisition, each patient was repositioned and a gated SPECT MPI image was reacquired. The two data sets were first processed blinded from each other by the same technologist in different weeks. These processed data were then realigned by the automatic tool, and manual side-by-side processing was carried out. All processing methods used standard iterative reconstruction and Butterworth filtering. The Emory Cardiac Toolbox was used to measure the LV function and dyssynchrony parameters. Results The automatic tool failed in one patient, who had a large, severe scar in the inferobasal wall. In the remaining 29 patients, the repeatability of the LV function and dyssynchrony parameters after automatic alignment was significantly improved from blinded processing and was comparable to manual side-by-side processing. Conclusion The automatic alignment tool can be an alternative method to manual side-by-side processing to improve the repeatability of LV function and dyssynchrony measurements by serial gated SPECT MPI. PMID:23211996

Nuclear medicine imaging of locally advanced laryngeal and hypopharyngeal cancer

NASA Astrophysics Data System (ADS)

Medvedeva, A.; Chernov, V.; Zeltchan, R.; Sinilkin, I.; Bragina, O.; Chijevskaya, S.; Choynzonov, E.; Goldberg, A.

2017-09-01

The diagnostic capabilities of nuclear medicine imaging in the detection and assessment of the spread of laryngeal/hypopharyngeal cancer were studied. A total of 40 patients with histologically verified laryngeal and hypopharyngeal cancer and 20 patients with benign laryngeal lesions were included into the study. Submucosal injections of 99mTc-MIBI and 99mTc-Alotech were made around the tumor. Single photon emission computed tomography (SPECT) was performed 20 minutes after the injection of 99mTc-MIBI. Sentinel lymph nodes (SLNs) were detected in 26 patients. In 18 hours after the injection of 99mTc-Alotech, SPECT was performed. In 24 hours after the injection of 99mTc-Alotech, intraoperative SLN detection was performed using Gamma Finder II. SPECT with 99mTc-MIBI revealed laryngeal and hypopharyngeal tumors in 38 of the 40 patients. The 99mTc-MIBI uptake in metastatic lymph nodes was visualized in 2 (17%) of the 12 patients. Twenty eight SLNs were detected by SPECT and 31 SLNs were identified using the intraoperative gamma probe. The percentage of 99mTc-Alotech in the SLN was 5-10% of the radioactivity in the injection site by SPECT and 18-33% by intraoperative gamma probe detection. Thus, SPECT with 99mTc-MIBI is an effective tool for the diagnosis of laryngeal/hypopharyngeal cancer. The sensitivity, specificity and accuracy of this technique were 95%, 80% and 92%, respectively. The use of 99mTc-Alotech for the detection of SLNs in patients with laryngeal/hypopharyngeal cancer is characterized by 92.8% sensitivity.

Extension of the International Atomic Energy Agency phantom study in image quantification: results of multicentre evaluation in Croatia.

PubMed

Grošev, Darko; Gregov, Marin; Wolfl, Miroslava Radić; Krstonošić, Branislav; Debeljuh, Dea Dundara

2018-06-07

To make quantitative methods of nuclear medicine more available, four centres in Croatia participated in the national intercomparison study, following the materials and methods used in the previous international study organized by the International Atomic Energy Agency (IAEA). The study task was to calculate the activities of four Ba sources (T1/2=10.54 years; Eγ=356 keV) using planar and single-photon emission computed tomography (SPECT) or SPECT/CT acquisitions of the sources inside a water-filled cylindrical phantom. The sources were previously calibrated by the US National Institute of Standards and Technology. Triple-energy window was utilized for scatter correction. Planar studies were corrected for attenuation correction (AC) using the conjugate-view method. For SPECT/CT studies, data from X-ray computed tomography were used for attenuation correction (CT-AC), whereas for SPECT-only acquisition, the Chang-AC method was applied. Using the lessons learned from the IAEA study, data were acquired according to the harmonized data acquisition protocol, and the acquired images were then processed using centralized data analysis. The accuracy of the activity quantification was evaluated as the ratio R between the calculated activity and the value obtained from National Institute of Standards and Technology. For planar studies, R=1.06±0.08; for SPECT/CT study using CT-AC, R=1.00±0.08; and for Chang-AC, R=0.89±0.12. The results are in accordance with those obtained within the larger IAEA study and confirm that SPECT/CT method is the most appropriate for accurate activity quantification.

Macrocyclic polyaminocarboxylates for stable radiometal antibody conjugates for therapy, spect and pet imaging

DOEpatents

Mease, Ronnie C.; Mausner, Leonard F.; Srivastava, Suresh C.

1997-06-17

A simple method for the synthesis of 1,4,7, 10-tetraazacyclododecane N,N'N",N'"-tetraacetic acid and 1,4,8,11-tetraazacyclotetradecane N,N',N",N'"-tetraacetic acid involves cyanomethylating 1,4,7, 10-tetraazacyclododecane or 1,4,8,11-tetraazacyclotetradecane to form a tetranitrile and hydrolyzing the tetranitrile. These macrocyclic compounds are functionalized through one of the carboxylates and then conjugated to various biological molecules including monoclonal antibodies. The resulting conjugated molecules are labeled with radiometals for SPECT and PET imaging and for radiotherapy.

SU-E-J-104: Single Photon Image From PET with Insertable SPECT Collimator for Boron Neutron Capture Therapy: A Feasibility Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, J; Yoon, D; Suh, T

2014-06-01

Purpose: The aim of our proposed system is to confirm the feasibility of extraction of two types of images from one positron emission tomography (PET) module with an insertable collimator for brain tumor treatment during the BNCT. Methods: Data from the PET module, neutron source, and collimator was entered in the Monte Carlo n-particle extended (MCNPX) source code. The coincidence events were first compiled on the PET detector, and then, the events of the prompt gamma ray were collected after neutron emission by using a single photon emission computed tomography (SPECT) collimator on the PET. The obtaining of full widthmore » at half maximum (FWHM) values from the energy spectrum was performed to collect effective events for reconstructed image. In order to evaluate the images easily, five boron regions in a brain phantom were used. The image profiles were extracted from the region of interest (ROI) of a phantom. The image was reconstructed using the ordered subsets expectation maximization (OSEM) reconstruction algorithm. The image profiles and the receiver operating characteristic (ROC) curve were compiled for quantitative analysis from the two kinds of reconstructed image. Results: The prompt gamma ray energy peak of 478 keV appeared in the energy spectrum with a FWHM of 41 keV (6.4%). On the basis of the ROC curve in Region A to Region E, the differences in the area under the curve (AUC) of the PET and SPECT images were found to be 10.2%, 11.7%, 8.2% (center, Region C), 12.6%, and 10.5%, respectively. Conclusion: We attempted to acquire the PET and SPECT images simultaneously using only PET without an additional isotope. Single photon images were acquired using an insertable collimator on a PET detector. This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, Information and Communication Technologies (ICT) and Future Planning (MSIP)(Grant No.2009 00420) and the Radiation Technology R and D program (Grant No.2013M2A2A7043498), Republic of Korea.« less

Dual-radiotracer translational SPECT neuroimaging. Comparison of three methods for the simultaneous brain imaging of D2/3 and 5-HT2A receptors.

PubMed

Tsartsalis, Stergios; Tournier, Benjamin B; Habiby, Selim; Ben Hamadi, Meriem; Barca, Cristina; Ginovart, Nathalie; Millet, Philippe

2018-04-30

SPECT imaging with two radiotracers at the same time is feasible if two different radioisotopes are employed, given their distinct energy emission spectra. In the case of 123 I and 125 I, dual SPECT imaging is not straightforward: 123 I emits photons at a principal energy emission spectrum of 143.1-179.9 keV. However, it also emits at a secondary energy spectrum (15-45 keV) that overlaps with the one of 125 I and the resulting cross-talk of emissions impedes the accurate quantification of 125 I. In this paper, we describe three different methods for the correction of this cross-talk and the simultaneous in vivo [ 123 I]IBZM and [ 125 I]R91150 imaging of D 2/3 and 5-HT 2A receptors in the rat brain. Three methods were evaluated for the correction of the effect of cross-talk in a series of simultaneous, [ 123 I]IBZM and [ 125 I]R91150 in vivo and phantom SPECT scans. Method 1 employs a dual-energy window (DEW) approach, in which the cross-talk on 125 I is considered a stable fraction of the energy emitted from 123 I at the principal emission spectrum. The coefficient describing the relationship between the emission of 123 I at the principal and the secondary spectrum was estimated from a series of single-radiotracer [ 123 I]IBZM SPECT studies. In Method 2, spectral factor analysis (FA) is applied to separate the radioactivity from 123 I and 125 I on the basis of their distinct emission patterns across the energy spectrum. Method 3 uses a modified simplified reference tissue model (SRTM C ) to describe the kinetics of [ 125 I]R91150. It includes the coefficient describing the cross-talk on 125 I from 123 I in the model parameters. The results of the correction of cross-talk on [ 125 I]R91150 binding potential (BP ND ) with each of the three methods, using cerebellum as the reference region, were validated against the results of a series of single-radiotracer [ 123 I]R91150 SPECT studies. In addition, the DEW approach (Method 1), considered to be the most straightforward to apply of the three, was further applied in a dual-radiotracer SPECT study of the relationship between D 2/3 and 5-HT 2A receptor binding in the striatum, both at the voxel and at the regional level. Average regional BP ND values of [ 125 I]R91150, estimated on the cross-talk corrected dual-radiotracer SPECT studies provided satisfactory correlations with the BP ND values for [ 123 I]R91150 from single-radiotracer studies: r = 0.92, p < 0.001 for Method 1, r = 0.92, p < 0.001 for Method 2, r = 0.92, p < 0.001, for Method 3. The coefficient describing the ratio of the 123 I-emitted radioactivity at the 125 I-emission spectrum to the radioactivity that it emits at its principal emission spectrum was 0.34 in vivo. Dual-radiotracer in vivo SPECT studies corrected with Method 1 demonstrated a positive correlation between D 2/3 and 5-HT 2A receptor binding in the rat nucleus accumbens at the voxel level. At the VOI-level, a positive correlation was confirmed in the same region (r = 0.78, p < 0.01). Dual-radiotracer SPECT imaging using 123 I and 125 I-labeled radiotracers is feasible if the cross-talk of 123 I on the 125 I emission spectrum is properly corrected. The most straightforward approach is Method 1, in which a fraction (34%) of the radioactivity emitted from 123 I at its principal energy spectrum is subtracted from the measured radioactivity at the spectrum of 125 I. With this method, a positive correlation between the binding of [ 123 I]IBZM and [ 125 I]R91150 was demonstrated in the rat nucleus accumbens. This result highlights the interest of dual-radiotracer SPECT imaging to study multiple neurotransmitter systems at the same time and under the same biological conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

[Regional cerebral blood flow measured by three-dimensional stereotactic surface projections (3D-SSP) of 123I-IMP SPECT in Parkinson disease patients with cognitive impairment].

PubMed

Sakai, Toshiyuki; Kuzuhara, Shigeki

2003-04-01

We investigated the regional cerebral blood flow (rCBF) in 8 patients with Parkinson disease (PD) with cognitive impairment (age; 64-82 years, Mini-Mental State Examination score = MMSE score; 22-6 points, Yahr stage; III-V), with the standard transaxial images and the Z-score images using the three-dimensional stereotactic surface projections (3D-SSP) of 123I-IMP SPECT. A contrast database was created by averaging extracted database sets of the contrast group (numbers; 14 cases, age; 64-82 years, MMSE score; > or = 29 points). The regions of the perfusion reduction shown on the standard transaxial images were similarly demonstrated on the Z-score images in 6 of the 8 patients, and only the Z-score images demonstrated definite regions of perfusion reduction in remaining 2 patients. Both the standard transaxial and Z-score images demonstrated the perfusion reduction in the temporo-parietal regions in all of the patients, and the Z-score images but not the standard transaxial ones detected the reduction in the posterior cingulate gyrus and precuneus in 3 patients. 3D-SSP images of 123I-IMP SPECT are thus more sensitive in detecting rCBF of the medial aspect of the parietal cortex than the standard transaxial images, and can be used as a diagnostic tool to objectively evaluate the cognitive function of PD patients.

[Time consumption and quality of an automated fusion tool for SPECT and MRI images of the brain].

PubMed

Fiedler, E; Platsch, G; Schwarz, A; Schmiedehausen, K; Tomandl, B; Huk, W; Rupprecht, Th; Rahn, N; Kuwert, T

2003-10-01

Although the fusion of images from different modalities may improve diagnostic accuracy, it is rarely used in clinical routine work due to logistic problems. Therefore we evaluated performance and time needed for fusing MRI and SPECT images using a semiautomated dedicated software. PATIENTS, MATERIAL AND METHOD: In 32 patients regional cerebral blood flow was measured using (99m)Tc ethylcystein dimer (ECD) and the three-headed SPECT camera MultiSPECT 3. MRI scans of the brain were performed using either a 0,2 T Open or a 1,5 T Sonata. Twelve of the MRI data sets were acquired using a 3D-T1w MPRAGE sequence, 20 with a 2D acquisition technique and different echo sequences. Image fusion was performed on a Syngo workstation using an entropy minimizing algorithm by an experienced user of the software. The fusion results were classified. We measured the time needed for the automated fusion procedure and in case of need that for manual realignment after automated, but insufficient fusion. The mean time of the automated fusion procedure was 123 s. It was for the 2D significantly shorter than for the 3D MRI datasets. For four of the 2D data sets and two of the 3D data sets an optimal fit was reached using the automated approach. The remaining 26 data sets required manual correction. The sum of the time required for automated fusion and that needed for manual correction averaged 320 s (50-886 s). The fusion of 3D MRI data sets lasted significantly longer than that of the 2D MRI data. The automated fusion tool delivered in 20% an optimal fit, in 80% manual correction was necessary. Nevertheless, each of the 32 SPECT data sets could be merged in less than 15 min with the corresponding MRI data, which seems acceptable for clinical routine use.

Spatial correspondence of 4D CT ventilation and SPECT pulmonary perfusion defects in patients with malignant airway stenosis

NASA Astrophysics Data System (ADS)

Castillo, Richard; Castillo, Edward; McCurdy, Matthew; Gomez, Daniel R.; Block, Alec M.; Bergsma, Derek; Joy, Sarah; Guerrero, Thomas

2012-04-01

To determine the spatial overlap agreement between four-dimensional computed tomography (4D CT) ventilation and single photon emission computed tomography (SPECT) perfusion hypo-functioning pulmonary defect regions in a patient population with malignant airway stenosis. Treatment planning 4D CT images were obtained retrospectively for ten lung cancer patients with radiographically demonstrated airway obstruction due to gross tumor volume. Each patient also received a SPECT perfusion study within one week of the planning 4D CT, and prior to the initiation of treatment. Deformable image registration was used to map corresponding lung tissue elements between the extreme component phase images, from which quantitative three-dimensional (3D) images representing the local pulmonary specific ventilation were constructed. Semi-automated segmentation of the percentile perfusion distribution was performed to identify regional defects distal to the known obstructing lesion. Semi-automated segmentation was similarly performed by multiple observers to delineate corresponding defect regions depicted on 4D CT ventilation. Normalized Dice similarity coefficient (NDSC) indices were determined for each observer between SPECT perfusion and 4D CT ventilation defect regions to assess spatial overlap agreement. Tidal volumes determined from 4D CT ventilation were evaluated versus measurements obtained from lung parenchyma segmentation. Linear regression resulted in a linear fit with slope = 1.01 (R2 = 0.99). Respective values for the average DSC, NDSC1 mm and NDSC2 mm for all cases and multiple observers were 0.78, 0.88 and 0.99, indicating that, on average, spatial overlap agreement between ventilation and perfusion defect regions was comparable to the threshold for agreement within 1-2 mm uncertainty. Corresponding coefficients of variation for all metrics were similarly in the range: 0.10%-19%. This study is the first to quantitatively assess 3D spatial overlap agreement between clinically acquired SPECT perfusion and specific ventilation from 4D CT. Results suggest high correlation between methods within the sub-population of lung cancer patients with malignant airway stenosis.

99mTc-Nanocolloid SPECT/MRI Fusion for the Selective Assessment of Nonenlarged Sentinel Lymph Nodes in Patients with Early-Stage Cervical Cancer.

PubMed

Hoogendam, Jacob P; Zweemer, Ronald P; Hobbelink, Monique G G; van den Bosch, Maurice A A J; Verheijen, René H M; Veldhuis, Wouter B

2016-04-01

We aimed to explore the accuracy of (99m)Tc SPECT/MRI fusion for the selective assessment of nonenlarged sentinel lymph nodes (SLNs) for diagnosing metastases in early-stage cervical cancer patients. We consecutively included stage IA1-IIB1 cervical cancer patients who presented to our tertiary referral center between March 2011 and February 2015. Patients with enlarged lymph nodes (short axis ≥ 10 mm) on MRI were excluded. Patients underwent an SLN procedure with preoperative (99m)Tc-nanocolloid SPECT/CT-based SLN mapping. When fused datasets of the SPECT and MR images were created, SLNs could be identified on the MR image with accurate correlation to the histologic result of each individual SLN. An experienced radiologist, masked to histology, retrospectively reviewed all fused SPECT/MR images and scored morphologic SLN parameters on a standardized case report form. Logistic regression and receiver-operating curves were used to model the parameters against the SLN status. In 75 cases, 136 SLNs were eligible for analysis, of which 13 (9.6%) contained metastases (8 cases). Three parameters-short-axis diameter, long-axis diameter, and absence of sharp demarcation-significantly predicted metastatic invasion of nonenlarged SLNs, with quality-adjusted odds ratios of 1.42 (95% confidence interval [CI], 1.01-1.99), 1.28 (95% CI, 1.03-1.57), and 7.55 (95% CI, 1.09-52.28), respectively. The area under the curve of the receiver-operating curves combining these parameters was 0.749 (95% CI, 0.569-0.930). Heterogeneous gadolinium enhancement, cortical thickness, round shape, or SLN size, compared with the nearest non-SLN, showed no association with metastases (P= 0.055-0.795). In cervical cancer patients without enlarged lymph nodes, selective evaluation of only the SLNs-for size and absence of sharp demarcation-can be used to noninvasively assess the presence of metastases. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Machine-learning model observer for detection and localization tasks in clinical SPECT-MPI

NASA Astrophysics Data System (ADS)

Parages, Felipe M.; O'Connor, J. Michael; Pretorius, P. Hendrik; Brankov, Jovan G.

2016-03-01

In this work we propose a machine-learning MO based on Naive-Bayes classification (NB-MO) for the diagnostic tasks of detection, localization and assessment of perfusion defects in clinical SPECT Myocardial Perfusion Imaging (MPI), with the goal of evaluating several image reconstruction methods used in clinical practice. NB-MO uses image features extracted from polar-maps in order to predict lesion detection, localization and severity scores given by human readers in a series of 3D SPECT-MPI. The population used to tune (i.e. train) the NB-MO consisted of simulated SPECT-MPI cases - divided into normals or with lesions in variable sizes and locations - reconstructed using filtered backprojection (FBP) method. An ensemble of five human specialists (physicians) read a subset of simulated reconstructed images, and assigned a perfusion score for each region of the left-ventricle (LV). Polar-maps generated from the simulated volumes along with their corresponding human scores were used to train five NB-MOs (one per human reader), which are subsequently applied (i.e. tested) on three sets of clinical SPECT-MPI polar maps, in order to predict human detection and localization scores. The clinical "testing" population comprises healthy individuals and patients suffering from coronary artery disease (CAD) in three possible regions, namely: LAD, LcX and RCA. Each clinical case was reconstructed using three reconstruction strategies, namely: FBP with no SC (i.e. scatter compensation), OSEM with Triple Energy Window (TEW) SC method, and OSEM with Effective Source Scatter Estimation (ESSE) SC. Alternative Free-Response (AFROC) analysis of perfusion scores shows that NB-MO predicts a higher human performance for scatter-compensated reconstructions, in agreement with what has been reported in published literature. These results suggest that NB-MO has good potential to generalize well to reconstruction methods not used during training, even for reasonably dissimilar datasets (i.e. simulated vs. clinical).

Current application and future perspectives of PSMA PET imaging in prostate cancer.

PubMed

Ceci, Francesco; Castellucci, Paolo; Fanti, Stefano

2018-03-08

As precision medicine evolves, the contribution of molecular imaging to the management of prostate cancer (PCa) patients, especially for Positron Emission Tomography (PET) imaging, is gaining importance. Highly successful approaches to measure the expression of the prostate specific membrane antigen (PSMA) have been introduced recently. PSMA, the glutamate carboxypeptidase II (GCP-II), is a membrane bound metallo-peptidase that is overexpressed in 90-100% of PCa cells. Due to its selective over-expression, PSMA is a reliable tissue marker for prostate cancer and is considered an ideal target for tumor specific imaging and therapy. A variety of PET and SPECT probes targeting this peptide receptor have been introduced. These are undergoing extensive clinical evaluations. Initial results attest to a high accuracy for disease detection compared conventional radiology (CT or MRI) and other nuclear medicine procedure (choline PET or fluciclovine PET). However, prospective evaluation of the impact on patient management for PSMA-ligand PET and its impact on patient outcome is currently missing. Finally, PSMA inhibitors can be radio-labeled with diagnostic (68Ga-PSMA-11), or therapeutic nuclides (177Lu/225Ac PSMA-617) to be used as theranostic agent. Initial results showed that PSMA-targeted radioligand therapy (RLT) can potentially delay disease progression in metastatic castrate-resistant PCa. This review aims to explore the current application of PSMA based imaging in prostate cancer, reporting about main advantages and limitations of this new theranostic procedure. The future perspectives and potential the applications of this agent will be also discussed.

Impact of scar thickness on the assessment of viability using dobutamine echocardiography and thallium single-photon emission computed tomography: a comparison with contrast-enhanced magnetic resonance imaging.

PubMed

Nelson, Charles; McCrohon, Jane; Khafagi, Frederick; Rose, Stephen; Leano, Rodel; Marwick, Thomas H

2004-04-07

We sought to determine whether the transmural extent of scar (TES) explains discordances between dobutamine echocardiography (DbE) and thallium single-photon emission computed tomography (Tl-SPECT) in the detection of viable myocardium (VM). Discrepancies between DbE and Tl-SPECT are often attributed to differences between contractile reserve and membrane integrity, but may also reflect a disproportionate influence of nontransmural scar on thickening at DbE. Sixty patients (age 62 +/- 12 years; 10 women and 50 men) with postinfarction left ventricular dysfunction underwent standard rest-late redistribution Tl-SPECT and DbE. Viable myocardium was identified when dysfunctional segments showed Tl activity >60% on the late-redistribution image or by low-dose augmentation at DbE. Contrast-enhanced magnetic resonance imaging (ceMRI) was used to divide TES into five groups: 0%, <25%, 26% to 50%, 51% to 75%, and >75% of the wall thickness replaced by scar. As TES increased, both the mean Tl uptake and change in wall motion score decreased significantly (both p < 0.001). However, the presence of subendocardial scar was insufficient to prevent thickening; >50% of segments still showed contractile function with TES of 25% to 75%, although residual function was uncommon with TES >75%. The relationship of both tests to increasing TES was similar, but Tl-SPECT identified VM more frequently than DbE in all groups. Among segments without scar or with small amounts of scar (<25% TES), >50% were viable by SPECT. Both contractile reserve and perfusion are sensitive to the extent of scar. However, contractile reserve may be impaired in the face of no or minor scar, and thickening may still occur with extensive scar.

Synthesis of Biocompatible Nanoparticulate Coordination Polymers for Diagnostic and Therapeutic Applications

NASA Astrophysics Data System (ADS)

Kandanapitiye, Murthi S.

The combination of nanotechnology with medicinal chemistry has developed into a burgeoning research area. Nanomaterials (NMs) could be seamlessly interfaced with various facets in biology, biochemistry, medicinal chemistry and environmental chemistry that may not be available to the same material in the bulk scale. This dissertation research has focused on the development of nanoparticulate coordination polymers for diagnostic and therapeutic applications. Modern imaging techniques include X-ray computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and positron emission tomography (PET). We have successfully developed several types of nanoparticulate diagnostics and therapeutics that have some potential usefulness in biomedicine. Synthesis and characterization of nanoparticulate based PET (Positron emission tomography)/SPECT (Single photon emission computed tomography) are discussed in chapter 3. In chapter 4, preparation and potential utility of non-gadolinium based MRI contrast agent are reported for T1-weighted application. As far as the solely effectiveness of relaxation is concerned, Gd-based T 1-weighted MRI contrast agents have excellent enhancement of image contrast but they have risks of biological toxicity. Consequently, the search for T 1-weighted CAs with high efficacy and low toxicity has gained attention toward the Mn(II) and Fe(III). Fe(III) is considered to be more toxic to cells because free ferric or ferrous ions can catalyze the production of reactive oxygen species via the Fenton reactions. Paramagnetic chelates of Mn(II) could be employed as T1-weighted CAs. However, it is challenging to design and synthesize highly stable Mn(II) complexes that could maintain the integrity when administered to living system. Chapter 4 describes the synthesis and utility of nanoparticulate Mn analogue of Prussian blue (K2Mn 3[FeII(CN)6]2) as an effective T1 MRI contrast agent for cellular imaging X-ray computed tomography is capable of delineating the 3-D images of soft tissues with superb quality. The variation of X-ray attenuation from one tissue to another is used to generate the well spatial resolved superb quality images. Exogenous radiopaque agents are necessary for the superb visualization of different types of soft tissues. Heavy metals with high atomic number are better suited for biomedical applications to enhance the image contrast due to their high mass attenuation coefficient. Bismuth (Z- 83) is the nonradioactive, heaviest, nontoxic element available among the other closest neighbors (Hg, Tl, Pb and Po) of the periodic table. We have set out to search for compounds that are hydrolytically stable, more efficient and more amenable in terms of biocompatibility. Moreover this new discovery can significantly reduce the average radiation dose in one CT scan. We have discovered a simple one-step aqueous solution route for preparing biocompatible and ultra-small bismuth oxyiodide BiOI nanoparticles and investigated their potential application as an efficient CT contrast agent. Our ultra-small monodisperse BiOI NPs have excellent water dispersability, thermodynamic stability, kinetic inertness, high biocompatibility and superior attenuation power, suggesting their potential as an organ-specific CT contrast agent that may fill the gap left by the other nanoparticulate and iodine-based CT contrasting agents. The chapter 6 of this dissertation discusses synthesis and characterization of novel nanoparticulate therapeutics and theranostics. D-penicillamine has the highest efficacy, and hence is currently the most widely used drug for WD across the world. We have prepared the D-PEN-conjugated Au NPs of the average size of 16 [special character omited] 2 nm with superb water dispersability, and examined the kinetics and selectivity of copper binding of such NPs in aqueous solution. We also studied the cellular uptake, cytotoxicity and intracellular copper removal of these NPs to demonstrate their potential as a novel cell-penetrable copper detoxifying agent. Our approach of tackling these problems focuses on the development of cell-permeable copper-depleting nanoparticles that can be surface-engineered to be potentially organ-specific when targeting agents are used to form new-generation drugs for WD. The latter part of chapter 6, we describe the synthesis, characterization of zinc analogue of Prussian blue (K2Zn3[Fe(CN) 6]2-ZnPB) for intracellular copper detoxification. (Abstract shortened by ProQuest.).

Improved heuristics for early melanoma detection using multimode hyperspectral dermoscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Vasefi, Fartash; MacKinnon, Nicholas B.; Booth, Nicholas; Farkas, Daniel L.

2017-02-01

Purpose: To determine the performance of a multimode dermoscopy system (SkinSpect) designed to quantify and 3-D map in vivo melanin and hemoglobin concentrations in skin and its melanoma scoring system, and compare the results accuracy with SIAscopy, and histopathology. Methods: A multimode imaging dermoscope is presented that combines polarization, fluorescence and hyperspectral imaging to accurately map the distribution of skin melanin, collagen and hemoglobin in pigmented lesions. We combine two depth-sensitive techniques: polarization, and hyperspectral imaging, to determine the spatial distribution of melanin and hemoglobin oxygenation in a skin lesion. By quantifying melanin absorption in pigmented areas, we can also more accurately estimate fluorescence emission distribution mainly from skin collagen. Results and discussion: We compared in vivo features of melanocytic lesions (N = 10) extracted by non-invasive SkinSpect and SIMSYS-MoleMate SIAscope, and correlate them to pathology report. Melanin distribution at different depths as well as hemodynamics including abnormal vascularity we detected will be discussed. We will adapt SkinSpect scoring with ABCDE (asymmetry , border, color, diameter, evolution) and seven point dermatologic checklist including: (1) atypical pigment network, (2) blue-whitish veil, (3) atypical vascular pattern, (4) irregular streaks, (5) irregular pigmentation, (6) irregular dots and globules, (7) regression structures estimated by dermatologist. Conclusion: Distinctive, diagnostic features seen by SkinSpect in melanoma vs. normal pigmented lesions will be compared by SIAscopy and results from histopathology.

Investigation of optimal acquisition time of myocardial perfusion scintigraphy using cardiac focusing-collimator

NASA Astrophysics Data System (ADS)

Niwa, Arisa; Abe, Shinji; Fujita, Naotoshi; Kono, Hidetaka; Odagawa, Tetsuro; Fujita, Yusuke; Tsuchiya, Saki; Kato, Katsuhiko

2015-03-01

Recently myocardial perfusion SPECT imaging acquired using the cardiac focusing-collimator (CF) has been developed in the field of nuclear cardiology. Previously we have investigated the basic characteristics of CF using physical phantoms. This study was aimed at determining the acquisition time for CF that enables to acquire the SPECT images equivalent to those acquired by the conventional method in 201TlCl myocardial perfusion SPECT. In this study, Siemens Symbia T6 was used by setting the torso phantom equipped with the cardiac, pulmonary, and hepatic components. 201TlCl solution were filled in the left ventricular (LV) myocardium and liver. Each of CF, the low energy high resolution collimator (LEHR), and the low medium energy general purpose collimator (LMEGP) was set on the SPECT equipment. Data acquisitions were made by regarding the center of the phantom as the center of the heart in CF at various acquisition times. Acquired data were reconstructed, and the polar maps were created from the reconstructed images. Coefficient of variation (CV) was calculated as the mean counts determined on the polar maps with their standard deviations. When CF was used, CV was lower at longer acquisition times. CV calculated from the polar maps acquired using CF at 2.83 min of acquisition time was equivalent to CV calculated from those acquired using LEHR in a 180°acquisition range at 20 min of acquisition time.

Pinhole Micro-SPECT/CT for Noninvasive Monitoring and Quantitation of Oncolytic Virus Dispersion and Percent Infection in Solid Tumors

PubMed Central

Penheiter, Alan R.; Griesmann, Guy E.; Federspiel, Mark J.; Dingli, David; Russell, Stephen J.; Carlson, Stephanie K.

2011-01-01

The purpose of our study was to validate the ability of pinhole micro-single-photon emission computed tomography/computed tomography (SPECT/CT) to 1) accurately resolve the intratumoral dispersion pattern and 2) quantify the infection percentage in solid tumors of an oncolytic measles virus encoding the human sodium iodide symporter (MV-NIS). NIS RNA level and dispersion pattern were determined in control and MV-NIS infected BxPC-3 pancreatic tumor cells and mouse xenografts using quantitative, real-time, reverse transcriptase, polymerase chain reaction, autoradiography, and immunohistochemistry (IHC). Mice with BxPC-3 xenografts were imaged with 123I or 99TcO4 micro-SPECT/CT. Tumor dimensions and radionuclide localization were determined with imaging software. Linear regression and correlation analyses were performed to determine the relationship between tumor infection percentage and radionuclide uptake (% injected dose per gram) above background and a highly significant correlation was observed (r2 = 0.947). A detection threshold of 1.5-fold above the control tumor uptake (background) yielded a sensitivity of 2.7% MV-NIS infected tumor cells. We reliably resolved multiple distinct intratumoral zones of infection from noninfected regions. Pinhole micro-SPECT/CT imaging using the NIS reporter demonstrated precise localization and quantitation of oncolytic MV-NIS infection and can replace more time-consuming and expensive analyses (eg, autoradiography and IHC) that require animal sacrifice. PMID:21753796

Single-Photon Emission Computed Tomography Is an Ambiguous Imaging Method on Initial Diagnosis for Acute Encephalopathy.

PubMed

Yamanaka, Gaku; Morishita, Nastumi; Oana, Shingo; Takeshita, Mika; Morichi, Shinichiro; Ishida, Yu; Kashiwagi, Yasuyo; Kawashima, Hisashi

2016-01-01

The distinction between acute encephalopathy (AE) and convulsive disorders with pyrexia may be problematic. We analyzed the clinical and laboratory features in 127 children who were admitted for suspected AE. They were categorized into (1) definite acute encephalopathy group (DAEG; n = 17, abnormal findings on electroencephalography [EEG], magnetic resonance imaging, or single-photon emission computed tomography [SPECT] with prolonged impaired consciousness), (2) probable acute encephalopathy group (PAEG; n = 21, abnormal findings without prolonged impaired consciousness), and (3) nonacute encephalopathy group (NAEG; n = 89). Cerebrospinal fluid interleukin-6 (CSF IL-6), and serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatine phosphokinase levels were significantly higher in DAEG compared with NAEG but not PAEG. No significant differences were observed between DAEG and PAEG except for serum creatinine levels. In PAEG, an area of hypoperfusion was observed on SPECT images of nine patients with normal CSF IL-6 levels. AE was suspected in two PAEG patients who exhibited high CSF IL-6 levels and abnormal EEG findings without abnormal SPECT findings. All seven patients with severe neurological sequelae were categorized to DAEG. CSF IL-6 and serum AST, ALT, and creatine kinase levels may be valid predictors of typical AE; prolonged impaired consciousness is an important sign of AE. However, SPECT may not be suitable for initial diagnosis of AE. Georg Thieme Verlag KG Stuttgart · New York.

SPECT imaging of fibrin using fibrin-binding peptides.

PubMed

Starmans, Lucas W E; van Duijnhoven, Sander M J; Rossin, Raffaella; Aime, Silvio; Daemen, Mat J A P; Nicolay, Klaas; Grüll, Holger

2013-01-01

Noninvasive detection of fibrin in vivo using diagnostic imaging modalities may improve clinical decision-making on possible therapeutic options in atherosclerosis, cancer and thrombus-related pathologies such as pulmonary embolism and deep venous thrombosis. The aim of this study was to assess the potential of a novel (111)In-labeled fibrin-binding peptide (FibPep) to visualize thrombi in mice noninvasively using single-photon emission computed tomography (SPECT). FibPep and a negative control peptide (NCFibPep) were synthesized and their fibrin-binding properties were assessed in vitro. FibPep showed enhanced binding compared with NCFibPep to both fibrin and blood clots. FibPep bound to fibrin with a dissociation constant (K(d)) of 0.8 μ m, whereas NCFibPep displayed at least a 100-fold lower affinity towards fibrin. A FeCl3 -injury carotid artery thrombosis mouse model was used to evaluate the peptides in vivo. FibPep and NCFibPep displayed rapid blood clearance and were eliminated via the renal pathway. In vivo SPECT imaging using FibPep allowed clear visualization of thrombi. Ex vivo biodistribution showed significantly increased uptake of FibPep in the thrombus-containing carotid in comparison to the noninjured carotid (5.7 ± 0.7 and 0.6 ± 0.4% injected dose per gram (%ID g(-1)), respectively; p < 0.01; n = 4), whereas nonspecific NCFibPep did not (0.4 ± 0.2 and 0.3 ± 0.0%ID g(-1), respectively; n = 4). In conclusion, FibPep displayed high affinity towards fibrin in vitro and rapid blood clearance in vivo, and allowed sensitive detection of thrombi using SPECT imaging. Therefore, this particular imaging approach may provide a new tool to diagnose and monitor diseases such as atherosclerosis and cancer. Copyright © 2013 John Wiley & Sons, Ltd.

Imaging and modeling of flow in porous media using clinical nuclear emission tomography systems and computational fluid dynamics

NASA Astrophysics Data System (ADS)

Boutchko, Rostyslav; Rayz, Vitaliy L.; Vandehey, Nicholas T.; O'Neil, James P.; Budinger, Thomas F.; Nico, Peter S.; Druhan, Jennifer L.; Saloner, David A.; Gullberg, Grant T.; Moses, William W.

2012-01-01

This paper presents experimental and modeling aspects of applying nuclear emission tomography to study fluid flow in laboratory packed porous media columns of the type frequently used in geophysics, geochemistry and hydrology research. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are used as non-invasive tools to obtain dynamic 3D images of radioactive tracer concentrations. Dynamic sequences obtained using 18F-FDG PET are used to trace flow through a 5 cm diameter × 20 cm tall sand packed column with and without an impermeable obstacle. In addition, a custom-made rotating column setup placed in a clinical two-headed SPECT camera is used to image 99mTc-DTPA tracer propagation in a through-flowing column (10 cm diameter × 30 cm tall) packed with recovered aquifer sediments. A computational fluid dynamics software package FLUENT is used to model the observed flow dynamics. Tracer distributions obtained in the simulations in the smaller column uniformly packed with sand and in the column with an obstacle are remarkably similar to the reconstructed images in the PET experiments. SPECT results demonstrate strongly non-uniform flow patterns for the larger column slurry-packed with sub-surface sediment and slow upward flow. In the numerical simulation of the SPECT study, two symmetric channels with increased permeability are prescribed along the column walls, which result in the emergence of two well-defined preferential flow paths. Methods and results of this work provide new opportunities in hydrologic and biogeochemical research. The primary target application for developed technologies is non-destructive, non-perturbing, quantitative imaging of flow dynamics within laboratory scale porous media systems.

Imaging and modeling of flow in porous media using clinical nuclear emission tomography systems and computational fluid dynamics.

PubMed

Boutchko, Rostyslav; Rayz, Vitaliy L; Vandehey, Nicholas T; O'Neil, James P; Budinger, Thomas F; Nico, Peter S; Druhan, Jennifer L; Saloner, David A; Gullberg, Grant T; Moses, William W

2012-01-01

This paper presents experimental and modeling aspects of applying nuclear emission tomography to study fluid flow in laboratory packed porous media columns of the type frequently used in geophysics, geochemistry and hydrology research. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are used as non-invasive tools to obtain dynamic 3D images of radioactive tracer concentrations. Dynamic sequences obtained using 18 F-FDG PET are used to trace flow through a 5 cm diameter × 20 cm tall sand packed column with and without an impermeable obstacle. In addition, a custom-made rotating column setup placed in a clinical two-headed SPECT camera is used to image 99m Tc-DTPA tracer propagation in a through-flowing column (10 cm diameter × 30 cm tall) packed with recovered aquifer sediments. A computational fluid dynamics software package FLUENT is used to model the observed flow dynamics. Tracer distributions obtained in the simulations in the smaller column uniformly packed with sand and in the column with an obstacle are remarkably similar to the reconstructed images in the PET experiments. SPECT results demonstrate strongly non-uniform flow patterns for the larger column slurry-packed with sub-surface sediment and slow upward flow. In the numerical simulation of the SPECT study, two symmetric channels with increased permeability are prescribed along the column walls, which result in the emergence of two well-defined preferential flow paths. Methods and results of this work provide new opportunities in hydrologic and biogeochemical research. The primary target application for developed technologies is non-destructive, non-perturbing, quantitative imaging of flow dynamics within laboratory scale porous media systems.