Alzheimer disease: Quantitative analysis of I-123-iodoamphetamine SPECT brain imaging

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

Hellman, R.S.; Tikofsky, R.S.; Collier, B.D.

1989-07-01

To enable a more quantitative diagnosis of senile dementia of the Alzheimer type (SDAT), the authors developed and tested a semiautomated method to define regions of interest (ROIs) to be used in quantitating results from single photon emission computed tomography (SPECT) of regional cerebral blood flow performed with N-isopropyl iodine-123-iodoamphetamine. SPECT/IMP imaging was performed in ten patients with probable SDAT and seven healthy subjects. Multiple ROIs were manually and semiautomatically generated, and uptake was quantitated for each ROI. Mean cortical activity was estimated as the average of the mean activity in 24 semiautomatically generated ROIs; mean cerebellar activity was determinedmore » from the mean activity in separate ROIs. A ratio of parietal to cerebellar activity less than 0.60 and a ratio of parietal to mean cortical activity less than 0.90 allowed correct categorization of nine of ten and eight of ten patients, respectively, with SDAT and all control subjects. The degree of diminished mental status observed in patients with SDAT correlated with both global and regional changes in IMP uptake.« less

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.

Combined visual and semi-quantitative assessment of 123I-FP-CIT SPECT for the diagnosis of dopaminergic neurodegenerative diseases.

PubMed

Ueda, Jun; Yoshimura, Hajime; Shimizu, Keiji; Hino, Megumu; Kohara, Nobuo

2017-07-01

Visual and semi-quantitative assessments of 123 I-FP-CIT single-photon emission computed tomography (SPECT) are useful for the diagnosis of dopaminergic neurodegenerative diseases (dNDD), including Parkinson's disease, dementia with Lewy bodies, progressive supranuclear palsy, multiple system atrophy, and corticobasal degeneration. However, the diagnostic value of combined visual and semi-quantitative assessment in dNDD remains unclear. Among 239 consecutive patients with a newly diagnosed possible parkinsonian syndrome who underwent 123 I-FP-CIT SPECT in our medical center, 114 patients with a disease duration less than 7 years were diagnosed as dNDD with the established criteria or as non-dNDD according to clinical judgment. We retrospectively examined their clinical characteristics and visual and semi-quantitative assessments of 123 I-FP-CIT SPECT. The striatal binding ratio (SBR) was used as a semi-quantitative measure of 123 I-FP-CIT SPECT. We calculated the sensitivity and specificity of visual assessment alone, semi-quantitative assessment alone, and combined visual and semi-quantitative assessment for the diagnosis of dNDD. SBR was correlated with visual assessment. Some dNDD patients with a normal visual assessment had an abnormal SBR, and vice versa. There was no statistically significant difference between sensitivity of the diagnosis with visual assessment alone and semi-quantitative assessment alone (91.2 vs. 86.8%, respectively, p = 0.29). Combined visual and semi-quantitative assessment demonstrated superior sensitivity (96.7%) to visual assessment (p = 0.03) or semi-quantitative assessment (p = 0.003) alone with equal specificity. Visual and semi-quantitative assessments of 123 I-FP-CIT SPECT are helpful for the diagnosis of dNDD, and combined visual and semi-quantitative assessment shows superior sensitivity with equal specificity.

Simultaneous acquisition of (99m)Tc- and (123)I-labeled radiotracers using a preclinical SPECT scanner with CZT detectors.

PubMed

Kobayashi, Masato; Matsunari, Ichiro; Nishi, Kodai; Mizutani, Asuka; Miyazaki, Yoshiharu; Ogai, Kazuhiro; Sugama, Jyunko; Shiba, Kazuhiro; Kawai, Keiichi; Kinuya, Seigo

2016-05-01

Simultaneous acquisition of (99m)Tc and (123)I was evaluated using a preclinical SPECT scanner with cadmium zinc telluride (CZT)-based detectors. 10-ml cylindrical syringes contained about 37 MBq (99m)Tc-tetrofosmin ((99m)Tc-TF) or 37 MBq (123)I-15-(p-iodophenyl)-3R,S-methyl pentadecanoic acid ((123)I-BMIPP) were used to assess the relationship between these SPECT radioactive counts and radioactivity. Two 10-ml syringes contained 100 or 300 MBq (99m)Tc-TF and 100 MBq (123)I-BMIPP to assess the influence of (99m)Tc upscatter and (123)I downscatter, respectively. A rat-sized cylindrical phantom also contained both 100 or 300 MBq (99m)Tc-TF and 100 MBq (123)I-BMIPP. The two 10-ml syringes and phantom were scanned using a pinhole collimator for rats. Myocardial infarction model rats were examined using 300 MBq (99m)Tc-TF and 100 MBq (123)I-BMIPP. Two 1-ml syringes contained 105 MBq (99m)Tc-labeled hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) and 35 MBq (123)I-labeled N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane ((123)I-FP-CIT). The two 1-ml syringes were scanned using a pinhole collimator for mice. Normal mice were examined using 105 MBq (99m)Tc-HMPAO and 35 MBq (123)I-FP-CIT. The relationship between SPECT radioactive counts and radioactivity was excellent. Downscatter contamination of (123)I-BMIPP exhibited fewer radioactive counts for 300 MBq (99m)Tc-TF without scatter correction (SC) in 125-150 keV. There was no upscatter contamination of (99m)Tc-TF in 150-175 keV. In the rat-sized phantom, the radioactive count ratio decreased to 4.0 % for 300 MBq (99m)Tc-TF without SC in 125-150 keV. In the rats, myocardial images and radioactive counts of (99m)Tc-TF with the dual tracer were identical to those of the (99m)Tc-TF single injection. Downscatter contamination of (123)I-FP-CIT was 4.2 % without SC in 125-150 keV. In the first injection of (99m)Tc-HMPAO and second injection of (123)I-FP-CIT, brain images and radioactive counts

Molecular SPECT Imaging: An Overview

PubMed Central

Khalil, Magdy M.; Tremoleda, Jordi L.; Bayomy, Tamer B.; Gsell, Willy

2011-01-01

Molecular imaging has witnessed a tremendous change over the last decade. Growing interest and emphasis are placed on this specialized technology represented by developing new scanners, pharmaceutical drugs, diagnostic agents, new therapeutic regimens, and ultimately, significant improvement of patient health care. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) have their signature on paving the way to molecular diagnostics and personalized medicine. The former will be the topic of the current paper where the authors address the current position of the molecular SPECT imaging among other imaging techniques, describing strengths and weaknesses, differences between SPECT and PET, and focusing on different SPECT designs and detection systems. Radiopharmaceutical compounds of clinical as well-preclinical interest have also been reviewed. Moreover, the last section covers several application, of μSPECT imaging in many areas of disease detection and diagnosis. PMID:21603240

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

Relationship Between Coronary Contrast-Flow Quantitative Flow Ratio and Myocardial Ischemia Assessed by SPECT MPI.

PubMed

Smit, Jeff M; Koning, Gerhard; van Rosendael, Alexander R; Dibbets-Schneider, Petra; Mertens, Bart J; Jukema, J Wouter; Delgado, Victoria; Reiber, Johan H C; Bax, Jeroen J; Scholte, Arthur J

2017-10-01

A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called "contrast-flow quantitative flow ratio (cQFR)". Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p <0.001). A good relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters.

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

A collimator optimization method for quantitative imaging: application to Y-90 bremsstrahlung SPECT.

PubMed

Rong, Xing; Frey, Eric C

2013-08-01

Post-therapy quantitative 90Y bremsstrahlung single photon emission computed tomography (SPECT) has shown great potential to provide reliable activity estimates, which are essential for dose verification. Typically 90Y imaging is performed with high- or medium-energy collimators. However, the energy spectrum of 90Y bremsstrahlung photons is substantially different than typical for these collimators. In addition, dosimetry requires quantitative images, and collimators are not typically optimized for such tasks. Optimizing a collimator for 90Y imaging is both novel and potentially important. Conventional optimization methods are not appropriate for 90Y bremsstrahlung photons, which have a continuous and broad energy distribution. In this work, the authors developed a parallel-hole collimator optimization method for quantitative tasks that is particularly applicable to radionuclides with complex emission energy spectra. The authors applied the proposed method to develop an optimal collimator for quantitative 90Y bremsstrahlung SPECT in the context of microsphere radioembolization. To account for the effects of the collimator on both the bias and the variance of the activity estimates, the authors used the root mean squared error (RMSE) of the volume of interest activity estimates as the figure of merit (FOM). In the FOM, the bias due to the null space of the image formation process was taken in account. The RMSE was weighted by the inverse mass to reflect the application to dosimetry; for a different application, more relevant weighting could easily be adopted. The authors proposed a parameterization for the collimator that facilitates the incorporation of the important factors (geometric sensitivity, geometric resolution, and septal penetration fraction) determining collimator performance, while keeping the number of free parameters describing the collimator small (i.e., two parameters). To make the optimization results for quantitative 90Y bremsstrahlung SPECT more

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.

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

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

Preclinical MR fingerprinting (MRF) at 7 T: effective quantitative imaging for rodent disease models.

PubMed

Gao, Ying; Chen, Yong; Ma, Dan; Jiang, Yun; Herrmann, Kelsey A; Vincent, Jason A; Dell, Katherine M; Drumm, Mitchell L; Brady-Kalnay, Susann M; Griswold, Mark A; Flask, Chris A; Lu, Lan

2015-03-01

High-field preclinical MRI scanners are now commonly used to quantitatively assess disease status and the efficacy of novel therapies in a wide variety of rodent models. Unfortunately, conventional MRI methods are highly susceptible to respiratory and cardiac motion artifacts resulting in potentially inaccurate and misleading data. We have developed an initial preclinical 7.0-T MRI implementation of the highly novel MR fingerprinting (MRF) methodology which has been described previously for clinical imaging applications. The MRF technology combines a priori variation in the MRI acquisition parameters with dictionary-based matching of acquired signal evolution profiles to simultaneously generate quantitative maps of T1 and T2 relaxation times and proton density. This preclinical MRF acquisition was constructed from a fast imaging with steady-state free precession (FISP) MRI pulse sequence to acquire 600 MRF images with both evolving T1 and T2 weighting in approximately 30 min. This initial high-field preclinical MRF investigation demonstrated reproducible and differentiated estimates of in vitro phantoms with different relaxation times. In vivo preclinical MRF results in mouse kidneys and brain tumor models demonstrated an inherent resistance to respiratory motion artifacts as well as sensitivity to known pathology. These results suggest that MRF methodology may offer the opportunity for the quantification of numerous MRI parameters for a wide variety of preclinical imaging applications. Copyright © 2015 John Wiley & Sons, Ltd.

Quantitative multi-pinhole small-animal SPECT: uniform versus non-uniform Chang attenuation correction.

PubMed

Wu, C; de Jong, J R; Gratama van Andel, H A; van der Have, F; Vastenhouw, B; Laverman, P; Boerman, O C; Dierckx, R A J O; Beekman, F J

2011-09-21

Attenuation of photon flux on trajectories between the source and pinhole apertures affects the quantitative accuracy of reconstructed single-photon emission computed tomography (SPECT) images. We propose a Chang-based non-uniform attenuation correction (NUA-CT) for small-animal SPECT/CT with focusing pinhole collimation, and compare the quantitative accuracy with uniform Chang correction based on (i) body outlines extracted from x-ray CT (UA-CT) and (ii) on hand drawn body contours on the images obtained with three integrated optical cameras (UA-BC). Measurements in phantoms and rats containing known activities of isotopes were conducted for evaluation. In (125)I, (201)Tl, (99m)Tc and (111)In phantom experiments, average relative errors comparing to the gold standards measured in a dose calibrator were reduced to 5.5%, 6.8%, 4.9% and 2.8%, respectively, with NUA-CT. In animal studies, these errors were 2.1%, 3.3%, 2.0% and 2.0%, respectively. Differences in accuracy on average between results of NUA-CT, UA-CT and UA-BC were less than 2.3% in phantom studies and 3.1% in animal studies except for (125)I (3.6% and 5.1%, respectively). All methods tested provide reasonable attenuation correction and result in high quantitative accuracy. NUA-CT shows superior accuracy except for (125)I, where other factors may have more impact on the quantitative accuracy than the selected attenuation correction.

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.

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

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

Preclinical Magnetic Resonance Fingerprinting (MRF) at 7 T: Effective Quantitative Imaging for Rodent Disease Models

PubMed Central

Gao, Ying; Chen, Yong; Ma, Dan; Jiang, Yun; Herrmann, Kelsey A.; Vincent, Jason A.; Dell, Katherine M.; Drumm, Mitchell L.; Brady-Kalnay, Susann M.; Griswold, Mark A.; Flask, Chris A.; Lu, Lan

2015-01-01

High field, preclinical magnetic resonance imaging (MRI) scanners are now commonly used to quantitatively assess disease status and efficacy of novel therapies in a wide variety of rodent models. Unfortunately, conventional MRI methods are highly susceptible to respiratory and cardiac motion artifacts resulting in potentially inaccurate and misleading data. We have developed an initial preclinical, 7.0 T MRI implementation of the highly novel Magnetic Resonance Fingerprinting (MRF) methodology that has been previously described for clinical imaging applications. The MRF technology combines a priori variation in the MRI acquisition parameters with dictionary-based matching of acquired signal evolution profiles to simultaneously generate quantitative maps of T1 and T2 relaxation times and proton density. This preclinical MRF acquisition was constructed from a Fast Imaging with Steady-state Free Precession (FISP) MRI pulse sequence to acquire 600 MRF images with both evolving T1 and T2 weighting in approximately 30 minutes. This initial high field preclinical MRF investigation demonstrated reproducible and differentiated estimates of in vitro phantoms with different relaxation times. In vivo preclinical MRF results in mouse kidneys and brain tumor models demonstrated an inherent resistance to respiratory motion artifacts as well as sensitivity to known pathology. These results suggest that MRF methodology may offer the opportunity for quantification of numerous MRI parameters for a wide variety of preclinical imaging applications. PMID:25639694

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.

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.

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.

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

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

Evaluation of patients with painful total hip arthroplasty using combined single photon emission tomography and conventional computerized tomography (SPECT/CT) - a comparison of semi-quantitative versus 3D volumetric quantitative measurements.

PubMed

Barthassat, Emilienne; Afifi, Faik; Konala, Praveen; Rasch, Helmut; Hirschmann, Michael T

2017-05-08

It was the primary purpose of our study to evaluate the inter- and intra-observer reliability of a standardized SPECT/CT algorithm for evaluating patients with painful primary total hip arthroplasty (THA). The secondary purpose was a comparison of semi-quantitative and 3D volumetric quantification method for assessment of bone tracer uptake (BTU) in those patients. A novel SPECT/CT localization scheme consisting of 14 femoral and 4 acetabular regions on standardized axial and coronal slices was introduced and evaluated in terms of inter- and intra-observer reliability in 37 consecutive patients with hip pain after THA. BTU for each anatomical region was assessed semi-quantitatively using a color-coded Likert type scale (0-10) and volumetrically quantified using a validated software. Two observers interpreted the SPECT/CT findings in all patients two times with six weeks interval between interpretations in random order. Semi-quantitative and quantitative measurements were compared in terms of reliability. In addition, the values were correlated using Pearson`s correlation. A factorial cluster analysis of BTU was performed to identify clinically relevant regions, which should be grouped and analysed together. The localization scheme showed high inter- and intra-observer reliabilities for all femoral and acetabular regions independent of the measurement method used (semiquantitative versus 3D volumetric quantitative measurements). A high to moderate correlation between both measurement methods was shown for the distal femur, the proximal femur and the acetabular cup. The factorial cluster analysis showed that the anatomical regions might be summarized into three distinct anatomical regions. These were the proximal femur, the distal femur and the acetabular cup region. The SPECT/CT algorithm for assessment of patients with pain after THA is highly reliable independent from the measurement method used. Three clinically relevant anatomical regions (proximal femoral

Quantitation of benzodiazepine receptor binding with PET [11C]iomazenil and SPECT [123I]iomazenil: preliminary results of a direct comparison in healthy human subjects.

PubMed

Bremner, J D; Baldwin, R; Horti, A; Staib, L H; Ng, C K; Tan, P Z; Zea-Ponce, Y; Zoghbi, S; Seibyl, J P; Soufer, R; Charney, D S; Innis, R B

1999-08-31

Although positron emission tomography (PET) and single photon emission computed tomography (SPECT) are increasingly used for quantitation of neuroreceptor binding, almost no studies to date have involved a direct comparison of the two. One study found a high level of agreement between the two techniques, although there was a systematic 30% increase in measures of benzodiazepine receptor binding in SPECT compared with PET. The purpose of the current study was to directly compare quantitation of benzodiazepine receptor binding in the same human subjects using PET and SPECT with high specific activity [11C]iomazenil and [123I]iomazenil, respectively. All subjects were administered a single bolus of high specific activity iomazenil labeled with 11C or 123I followed by dynamic PET or SPECT imaging of the brain. Arterial blood samples were obtained for measurement of metabolite-corrected radioligand in plasma. Compartmental modeling was used to fit values for kinetic rate constants of transfer of radioligand between plasma and brain compartments. These values were used for calculation of binding potential (BP = Bmax/Kd) and product of BP and the fraction of free non-protein-bound parent compound (V3'). Mean values for V3' in PET and SPECT were as follows: temporal cortex 23+/-5 and 22+/-3 ml/g, frontal cortex23+/-6 and 22+/-3 ml/g, occipital cortex 28+/-3 and 31+/-5 ml/g, and striatum 4+/-4 and 7+/-4 ml/g. These preliminary findings indicate that PET and SPECT provide comparable results in quantitation of neuroreceptor binding in the human brain.

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.

Comparison of 99mTc-MDP SPECT qualitative vs quantitative results in patients with suspected condylar hyperplasia.

PubMed

López Buitrago, D F; Ruiz Botero, J; Corral, C M; Carmona, A R; Sabogal, A

To compare qualitative vs quantitative results of Single Photon Emission Computerised Tomography (SPECT), calculated from percentage of 99m Tc-MDP (methylene diphosphonate) uptake, in condyles of patients with a presumptive clinical diagnosis of condylar hyperplasia. A retrospective, descriptive study was conducted on the 99m Tc-MDP SPECT bone scintigraphy reports from 51 patients, with clinical impression of facial asymmetry related to condylar hyperplasia referred by their specialist in orthodontics or maxillofacial surgery, to a nuclear medicine department in order to take this type of test. Quantitative data from 99m Tc-MDP condylar uptake of each were obtained and compared with qualitative image interpretation reported by a nuclear medicine expert. The concordances between the 51 qualitative and quantitative reports results was established. The total sample included 32 women (63%) and 19 men (37%). The patient age range was 13-45 years (21±8 years). According to qualitative reports, 19 patients were positive for right side condylar hyperplasia, 12 for left side condylar hyperplasia, with 8 bilateral, and 12 negative. The quantitative reports diagnosed 16 positives for right side condylar hyperplasia, 10 for left side condylar hyperplasia, and 25 negatives. Nuclear medicine images are an important diagnostic tool, but the qualitative interpretation of the images is not as reliable as the quantitative calculation. The agreement between the two types of report is low (39.2%, Kappa=0.13; P>.2). The main limitation of quantitative reports is that they do not register bilateral condylar hyperplasia cases. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

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.

Preclinical Evaluation of a Potential GSH Ester Based PET/SPECT Imaging Probe DT(GSHMe)₂ to Detect Gamma Glutamyl Transferase Over Expressing Tumors.

PubMed

Khurana, Harleen; Meena, Virendra Kumar; Prakash, Surbhi; Chuttani, Krishna; Chadha, Nidhi; Jaswal, Ambika; Dhawan, Devinder Kumar; Mishra, Anil Kumar; Hazari, Puja Panwar

2015-01-01

Gamma Glutamyl Transferase (GGT) is an important biomarker in malignant cancers. The redox processes ensuing from GGT-mediated metabolism of extracellular GSH are implicated in critical aspects of tumor cell biology. Reportedly, Glutathione monoethyl ester (GSHMe) is a substrate of GGT, which has been used for its rapid transport over glutathione. Exploring GGT to be an important target, a homobivalent peptide system, DT(GSHMe)2 was designed to target GGT-over expressing tumors for diagnostic purposes. DT(GSHMe)2 was synthesized, characterized and preclinically evaluated in vitro using toxicity, cell binding assays and time dependent experiments. Stable and defined radiochemistry with 99mTc and 68Ga was optimized for high radiochemical yield. In vivo biodistribution studies were conducted for different time points along with scintigraphic studies of radiolabeled DT(GSHMe)2 on xenografted tumor models. For further validation, in silico docking studies were performed on GGT (hGGT1, P19440). Preclinical in vitro evaluations on cell lines suggested minimal toxicity of DT(GSHMe)2 at 100 μM concentration. Kinetic analysis revealed transport of 99mTc-DT(GSHMe)2 occurs via a saturable high-affinity carrier with Michaelis constant (Km) of 2.25 μM and maximal transport rate velocity (Vmax) of 0.478 μM/min. Quantitative estimation of GGT expression from western blot experiments showed substantial expression with 41.6 ± 7.07 % IDV for tumor. Small animal micro PET (Positron Emission Tomography)/CT(Computed Tomography) coregistered images depicted significantly high uptake of DT(GSHMe)2 at the BMG-1 tumor site. ROI analysis showed high tumor to contra lateral muscle ratio of 9.33 in PET imaging studies. Avid accumulation of radiotracer was observed at tumor versus inflammation site at 2 h post i.v. injection in an Ehrlich Ascites tumor (EAT) mice model, showing evident specificity for tumor. We propose DT(GSHMe)2 to be an excellent candidate for prognostication and tumor

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.

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

Quantitative accuracy of the closed-form least-squares solution for targeted SPECT.

PubMed

Shcherbinin, S; Celler, A

2010-10-07

The aim of this study is to investigate the quantitative accuracy of the closed-form least-squares solution (LSS) for single photon emission computed tomography (SPECT). The main limitation for employing this method in actual clinical reconstructions is the computational cost related to operations with a large-sized system matrix. However, in some clinical situations, the size of the system matrix can be decreased using targeted reconstruction. For example, some oncology SPECT studies are characterized by intense tracer uptakes that are localized in relatively small areas, while the remaining parts of the patient body have only a low activity background. Conventional procedures reconstruct the activity distribution in the whole object, which leads to relatively poor image accuracy/resolution for tumors while computer resources are wasted, trying to rebuild diagnostically useless background. In this study, we apply a concept of targeted reconstruction to SPECT phantom experiments imitating such oncology scans. Our approach includes two major components: (i) disconnection of the entire imaging system of equations and extraction of only those parts that correspond to the targets, i.e., regions of interest (ROI) encompassing active containers/tumors and (ii) generation of the closed-form LSS for each target ROI. We compared these ROI-based LSS with those reconstructed by the conventional MLEM approach. The analysis of the five processed cases from two phantom experiments demonstrated that the LSS approach outperformed MLEM in terms of the noise level inside ROI. On the other hand, MLEM better recovered total activity if the number of iterations was large enough. For the experiment without background activity, the ROI-based LSS led to noticeably better spatial activity distribution inside ROI. However, the distributions pertaining to both approaches were practically identical for the experiment with the concentration ratio 7:1 between the containers and the background.

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

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.

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

Quantitative imaging biomarkers: the application of advanced image processing and analysis to clinical and preclinical decision making.

PubMed

Prescott, Jeffrey William

2013-02-01

The importance of medical imaging for clinical decision making has been steadily increasing over the last four decades. Recently, there has also been an emphasis on medical imaging for preclinical decision making, i.e., for use in pharamaceutical and medical device development. There is also a drive towards quantification of imaging findings by using quantitative imaging biomarkers, which can improve sensitivity, specificity, accuracy and reproducibility of imaged characteristics used for diagnostic and therapeutic decisions. An important component of the discovery, characterization, validation and application of quantitative imaging biomarkers is the extraction of information and meaning from images through image processing and subsequent analysis. However, many advanced image processing and analysis methods are not applied directly to questions of clinical interest, i.e., for diagnostic and therapeutic decision making, which is a consideration that should be closely linked to the development of such algorithms. This article is meant to address these concerns. First, quantitative imaging biomarkers are introduced by providing definitions and concepts. Then, potential applications of advanced image processing and analysis to areas of quantitative imaging biomarker research are described; specifically, research into osteoarthritis (OA), Alzheimer's disease (AD) and cancer is presented. Then, challenges in quantitative imaging biomarker research are discussed. Finally, a conceptual framework for integrating clinical and preclinical considerations into the development of quantitative imaging biomarkers and their computer-assisted methods of extraction is presented.

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.

Patient-specific dosimetry based on quantitative SPECT imaging and 3D-DFT convolution

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

Akabani, G.; Hawkins, W.G.; Eckblade, M.B.

1999-01-01

The objective of this study was to validate the use of a 3-D discrete Fourier Transform (3D-DFT) convolution method to carry out the dosimetry for I-131 for soft tissues in radioimmunotherapy procedures. To validate this convolution method, mathematical and physical phantoms were used as a basis of comparison with Monte Carlo transport (MCT) calculations which were carried out using the EGS4 system code. The mathematical phantom consisted of a sphere containing uniform and nonuniform activity distributions. The physical phantom consisted of a cylinder containing uniform and nonuniform activity distributions. Quantitative SPECT reconstruction was carried out using the Circular Harmonic Transformmore » (CHT) algorithm.« less

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 (-0.60SPECT/CT has better correlation with clinical outcome in LVRS candidates than do planar imaging, SPECT or qualitatively assessed CT, and is at least as valid as quantitatively assessed CT. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

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

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

Optimisation of quantitative lung SPECT applied to mild COPD: a software phantom simulation study.

PubMed

Norberg, Pernilla; Olsson, Anna; Alm Carlsson, Gudrun; Sandborg, Michael; Gustafsson, Agnetha

2015-01-01

The amount of inhomogeneities in a (99m)Tc Technegas single-photon emission computed tomography (SPECT) lung image, caused by reduced ventilation in lung regions affected by chronic obstructive pulmonary disease (COPD), is correlated to disease advancement. A quantitative analysis method, the CVT method, measuring these inhomogeneities was proposed in earlier work. To detect mild COPD, which is a difficult task, optimised parameter values are needed. In this work, the CVT method was optimised with respect to the parameter values of acquisition, reconstruction and analysis. The ordered subset expectation maximisation (OSEM) algorithm was used for reconstructing the lung SPECT images. As a first step towards clinical application of the CVT method in detecting mild COPD, this study was based on simulated SPECT images of an advanced anthropomorphic lung software phantom including respiratory and cardiac motion, where the mild COPD lung had an overall ventilation reduction of 5%. The best separation between healthy and mild COPD lung images as determined using the CVT measure of ventilation inhomogeneity and 125 MBq (99m)Tc was obtained using a low-energy high-resolution collimator (LEHR) and a power 6 Butterworth post-filter with a cutoff frequency of 0.6 to 0.7 cm(-1). Sixty-four reconstruction updates and a small kernel size should be used when the whole lung is analysed, and for the reduced lung a greater number of updates and a larger kernel size are needed. A LEHR collimator and 125 (99m)Tc MBq together with an optimal combination of cutoff frequency, number of updates and kernel size, gave the best result. Suboptimal selections of either cutoff frequency, number of updates and kernel size will reduce the imaging system's ability to detect mild COPD in the lung phantom.

Quantitatively accurate activity measurements with a dedicated cardiac SPECT camera: Physical phantom experiments

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

Pourmoghaddas, Amir, E-mail: apour@ottawaheart.ca; Wells, R. Glenn

Purpose: Recently, there has been increased interest in dedicated cardiac single photon emission computed tomography (SPECT) scanners with pinhole collimation and improved detector technology due to their improved count sensitivity and resolution over traditional parallel-hole cameras. With traditional cameras, energy-based approaches are often used in the clinic for scatter compensation because they are fast and easily implemented. Some of the cardiac cameras use cadmium-zinc-telluride (CZT) detectors which can complicate the use of energy-based scatter correction (SC) due to the low-energy tail—an increased number of unscattered photons detected with reduced energy. Modified energy-based scatter correction methods can be implemented, but theirmore » level of accuracy is unclear. In this study, the authors validated by physical phantom experiments the quantitative accuracy and reproducibility of easily implemented correction techniques applied to {sup 99m}Tc myocardial imaging with a CZT-detector-based gamma camera with multiple heads, each with a single-pinhole collimator. Methods: Activity in the cardiac compartment of an Anthropomorphic Torso phantom (Data Spectrum Corporation) was measured through 15 {sup 99m}Tc-SPECT acquisitions. The ratio of activity concentrations in organ compartments resembled a clinical {sup 99m}Tc-sestamibi scan and was kept consistent across all experiments (1.2:1 heart to liver and 1.5:1 heart to lung). Two background activity levels were considered: no activity (cold) and an activity concentration 1/10th of the heart (hot). A plastic “lesion” was placed inside of the septal wall of the myocardial insert to simulate the presence of a region without tracer uptake and contrast in this lesion was calculated for all images. The true net activity in each compartment was measured with a dose calibrator (CRC-25R, Capintec, Inc.). A 10 min SPECT image was acquired using a dedicated cardiac camera with CZT detectors (Discovery NM530c

SU-F-J-08: Quantitative SPECT Imaging of Ra-223 in a Phantom

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

Yue, J; Hobbs, R; Sgouros, G

Purpose: Ra-223 therapy of prostate cancer bone metastases is being used to treat patients routinely. However, the absorbed dose distribution at the macroscopic and microscopic scales remains elusive, due to the inability to image the small activities injected. Accurate activity quantification through imaging is essential to calculate the absorbed dose in organs and sub-units in radiopharmaceutical therapy, enabling personalized absorbed dose-based treatment planning methodologies and more effective and optimal treatments. Methods: A 22 cm diameter by 20 cm long cylindrical phantom, containing a 3.52 cm diameter sphere, was used. A total of 2.01 MBq of Ra-223 was placed in themore » phantom with 177.6 kBq in the sphere. Images were acquired on a dual-head Siemens Symbia T16 gamma camera using three 20% full-width energy windows and centered at 84, 154, and 269 keV (120 projections, 360° rotation, 45 s per view). We have implemented reconstruction of Ra-223 SPECT projections using OS-EM (up to 20 iterations of 10 subsets) with compensation for attenuation using CT-based attenuation maps, collimator-detector response (CDR) (including septal penetration, scatter and Pb x-ray modeling), and scatter in the patient using the effective source scatter estimation (ESSE) method. The CDR functions and scatter kernels required for ESSE were computed using the SIMIND MC simulation code. All Ra-223 photon emissions as well as gamma rays from the daughters Rn-219 and Bi-211 were modeled. Results: The sensitivity of the camera in the three combined windows was 107.3 cps/MBq. The visual quality of the SPECT images was reasonably good and the activity in the sphere was 27% smaller than the true activity. This underestimation is likely due to partial volume effect. Conclusion: Absolute quantitative Ra-223 SPECT imaging is achievable with careful attention to compensate for image degrading factors and system calibration.« less

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

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.

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

[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 .

The origins of SPECT and SPECT/CT.

PubMed

Hutton, Brian F

2014-05-01

Single photon emission computed tomography (SPECT) has a long history of development since its initial demonstration by Kuhl and Edwards in 1963. Although clinical utility has been dominated by the rotating gamma camera, there have been many technological innovations with the recent popularity of organ-specific dedicated SPECT systems. The combination of SPECT and CT evolved from early transmission techniques used for attenuation correction with the initial commercial systems predating the release of PET/CT. The development and acceptance of SPECT/CT has been relatively slow with continuing debate as to what cost/performance ratio is justified. Increasingly, fully diagnostic CT is combined with SPECT so as to facilitate optimal clinical utility.

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

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.

Pre-clinical Evaluation of a Cyanine-Based SPECT Probe for Multimodal Tumor Necrosis Imaging.

PubMed

Stammes, Marieke A; Knol-Blankevoort, Vicky T; Cruz, Luis J; Feitsma, Hans R I J; Mezzanotte, Laura; Cordfunke, Robert A; Sinisi, Riccardo; Dubikovskaya, Elena A; Maeda, Azusa; DaCosta, Ralph S; Bierau, Katja; Chan, Alan; Kaijzel, Eric L; Snoeks, Thomas J A; van Beek, Ermond R; Löwik, Clemens W G M

2016-12-01

Recently we showed that a number of carboxylated near-infrared fluorescent (NIRF) cyanine dyes possess strong necrosis avid properties in vitro as well as in different mouse models of spontaneous and therapy-induced tumor necrosis, indicating their potential use for cancer diagnostic- and prognostic purposes. In the previous study, the detection of the cyanines was achieved by whole body optical imaging, a technique that, due to the limited penetration of near-infrared light, is not suitable for investigations deeper than 1 cm within the human body. Therefore, in order to facilitate clinical translation, the purpose of the present study was to generate a necrosis avid cyanine-based NIRF probe that could also be used for single photon emission computed tomography (SPECT). For this, the necrosis avid NIRF cyanine HQ4 was radiolabeled with 111 indium, via the chelate diethylene triamine pentaacetic acid (DTPA). The necrosis avid properties of the radiotracer [ 111 In]DTPA-HQ4 were examined in vitro and in vivo in different breast tumor models in mice using SPECT and optical imaging. Moreover, biodistribution studies were performed to examine the pharmacokinetics of the probe in vivo. Using optical imaging and radioactivity measurements, in vitro, we showed selective accumulation of [ 111 In]DTPA-HQ4 in dead cells. Using SPECT and in biodistribution studies, the necrosis avidity of the radiotracer was confirmed in a 4T1 mouse breast cancer model of spontaneous tumor necrosis and in a MCF-7 human breast cancer model of chemotherapy-induced tumor necrosis. The radiotracer [ 111 In]DTPA-HQ4 possessed strong and selective necrosis avidity in vitro and in various mouse models of tumor necrosis in vivo, indicating its potential to be clinically applied for diagnostic purposes and to monitor anti-cancer treatment efficacy.

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

Simulated Design Strategies for SPECT Collimators to Reduce the Eddy Currents Induced by MRI Gradient Fields

NASA Astrophysics Data System (ADS)

Samoudi, Amine M.; Van Audenhaege, Karen; Vermeeren, Günter; Verhoyen, Gregory; Martens, Luc; Van Holen, Roel; Joseph, Wout

2015-10-01

Combining single photon emission computed tomography (SPECT) with magnetic resonance imaging (MRI) requires the insertion of highly conductive SPECT collimators inside the MRI scanner, resulting in an induced eddy current disturbing the combined system. We reduced the eddy currents due to the insert of a novel tungsten collimator inside transverse and longitudinal gradient coils. The collimator was produced with metal additive manufacturing, that is part of a microSPECT insert for a preclinical SPECT/MRI scanner. We characterized the induced magnetic field due to the gradient field and adapted the collimators to reduce the induced eddy currents. We modeled the x-, y-, and z-gradient coil and the different collimator designs and simulated them with FEKO, a three-dimensional method of moments / finite element methods (MoM/FEM) full-wave simulation tool. We used a time analysis approach to generate the pulsed magnetic field gradient. Simulation results show that the maximum induced field can be reduced by 50.82% in the final design bringing the maximum induced magnetic field to less than 2% of the applied gradient for all the gradient coils. The numerical model was validated with measurements and was proposed as a tool for studying the effect of a SPECT collimator within the MRI gradient coils.

Brain regions associated with cognitive impairment in patients with Parkinson disease: quantitative analysis of cerebral blood flow using 123I iodoamphetamine SPECT.

PubMed

Hattori, Naoya; Yabe, Ichiro; Hirata, Kenji; Shiga, Tohru; Sakushima, Ken; Tsuji-Akimoto, Sachiko; Sasaki, Hidenao; Tamaki, Nagara

2013-05-01

Cognitive impairment is a representative neuropsychiatric presentation that accompanies Parkinson disease (PD). The purpose of this study was to localize the cerebral regions associated with cognitive impairment in patients with PD using quantitative SPECT. Thirty-two patients with PD (mean [SD] age, 75 [8] years; 25 women; Hoehn-Yahr scores from 2 to 5) underwent quantitative brain SPECT using 123I iodoamphetamine. Parametric images of regional cerebral blood flow (rCBF) were spatially normalized to the standard brain atlas. First, voxel-by-voxel comparison between patients with PD with versus without cognitive impairment was performed to visualize overall trend of regional differences. Next, the individual quantitative rCBF values were extracted in representative cortical regions using a standard region-of-interest template to compare the quantitative rCBF values. Patients with cognitive impairment showed trends of lower rCBF in the left frontal and temporal cortices as well as in the bilateral medial frontal and anterior cingulate cortices in the voxel-by-voxel analyses. Region-of-interest-based analysis demonstrated significantly lower rCBF in the bilateral anterior cingulate cortices (right, 25.8 [5.5] vs 28.9 [5.7] mL per 100 g/min, P < 0.05; left, 25.8 [5.8] vs 29.1 [5.7] mL per 100 g/min, P < 0.05) associated with cognitive impairment. Patients with cognitive impairment showed lower rCBF in the left frontal and temporal cortices as well as in the bilateral medial frontal and anterior cingulate cortices. The results suggested dysexecutive function as an underlining mechanism of cognitive impairment in patients with PD.

Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters

NASA Astrophysics Data System (ADS)

Cheng, Lishui; Hobbs, Robert F.; Segars, Paul W.; Sgouros, George; Frey, Eric C.

2013-06-01

In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceuticals in tissues. Dose-volume histograms (DVHs) provide a useful summary representation of the 3D dose distribution and have been widely used for external beam treatment planning. Reliable 3D dosimetry requires an accurate 3D radioactivity distribution as the input. However, activity distribution estimates from SPECT are corrupted by noise and partial volume effects (PVEs). In this work, we systematically investigated OS-EM based quantitative SPECT (QSPECT) image reconstruction in terms of its effect on DVHs estimates. A modified 3D NURBS-based Cardiac-Torso (NCAT) phantom that incorporated a non-uniform kidney model and clinically realistic organ activities and biokinetics was used. Projections were generated using a Monte Carlo (MC) simulation; noise effects were studied using 50 noise realizations with clinical count levels. Activity images were reconstructed using QSPECT with compensation for attenuation, scatter and collimator-detector response (CDR). Dose rate distributions were estimated by convolution of the activity image with a voxel S kernel. Cumulative DVHs were calculated from the phantom and QSPECT images and compared both qualitatively and quantitatively. We found that noise, PVEs, and ringing artifacts due to CDR compensation all degraded histogram estimates. Low-pass filtering and early termination of the iterative process were needed to reduce the effects of noise and ringing artifacts on DVHs, but resulted in increased degradations due to PVEs. Large objects with few features, such as the liver, had more accurate histogram estimates and required fewer iterations and more smoothing for optimal results. Smaller objects with fine details, such as the kidneys, required more iterations and less

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

Quantitative evaluation improves specificity of myocardial perfusion SPECT in the assessment of functionally significant intermediate coronary artery stenoses: a comparative study with fractional flow reserve measurements.

PubMed

Sahiner, Ilgin; Akdemir, Umit O; Kocaman, Sinan A; Sahinarslan, Asife; Timurkaynak, Timur; Unlu, Mustafa

2013-02-01

Myocardial perfusion SPECT (MPS) is a noninvasive method commonly used for assessment of the hemodynamic significance of intermediate coronary stenoses. Fractional flow reserve (FFR) measurement is a well-validated invasive method used for the evaluation of intermediate stenoses. We aimed to determine the association between MPS and FFR findings in intermediate degree stenoses and evaluate the added value of quantification in MPS. Fifty-eight patients who underwent intracoronary pressure measurement in the catheterization laboratory to assess the physiological significance of intermediate (40-70%) left anterior descending (LAD) artery lesions, and who also underwent stress myocardial perfusion SPECT either for the assessment of an intermediate stenosis or for suspected coronary artery disease were analyzed retrospectively in the study. Quantitative analysis was performed using the 4DMSPECT program, with visual assessment performed by two experienced nuclear medicine physicians blinded to the angiographic findings. Summed stress scores (SSS) and summed difference scores (SDS) in the LAD artery territory according to the 20 segment model were calculated. A summed stress score of ≥ 3 and an SDS of ≥ 2 were assumed as pathologic, indicating significance of the lesion; a cutoff value of 0.75 was used to define abnormal FFR. Both visual and quantitative assessment results were compared with FFR using Chi-square (χ²) test. The mean time interval between two studies was 13 ± 11 days. FFR was normal in 45 and abnormal in 13 patients. Considering the FFR results as the gold standard method for assessing the significance of the lesion, the sensitivity and specificity of quantitative analysis determining the abnormal flow reserve were 85 and 84%, respectively, while visual analysis had a sensitivity of 77% and a specificity of 51%. There was a good agreement between the observers (κ = 0.856). Summed stress and difference scores demonstrated moderate inverse

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.

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.

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.

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

Quantitative diagnostic performance of myocardial perfusion SPECT with attenuation correction in women.

PubMed

Wolak, Arik; Slomka, Piotr J; Fish, Mathews B; Lorenzo, Santiago; Berman, Daniel S; Germano, Guido

2008-06-01

Attenuation correction (AC) for myocardial perfusion SPECT (MPS) had not been evaluated separately in women despite specific considerations in this group because of breast photon attenuation. We aimed to evaluate the performance of AC in women by using automated quantitative analysis of MPS to avoid any bias. Consecutive female patients--134 with a low likelihood (LLk) of coronary artery disease (CAD) and 114 with coronary angiography performed within less than 3 mo of MPS--who were referred for rest-stress electrocardiography-gated 99mTc-sestamibi MPS with AC were considered. Imaging data were evaluated for contour quality control. An additional 50 LLk studies in women were used to create equivalent normal limits for studies with AC and with no correction (NC). An experienced technologist unaware of the angiography and other results performed the contour quality control. All other processing was performed in a fully automated manner. Quantitative analysis was performed with the Cedars-Sinai myocardial perfusion analysis package. All automated segmental analyses were performed with the 17-segment, 5-point American Heart Association model. Summed stress scores (SSS) of > or =3 were considered abnormal. CAD (> or =70% stenosis) was present in 69 of 114 patients (60%). The normalcy rates were 93% for both NC and AC studies. The SSS for patients with CAD and without CAD for NC versus AC were 10.0 +/- 9.0 (mean +/- SD) versus 10.2 +/- 8.5 and 1.6 +/- 2.3 versus 1.8 +/- 2.5, respectively; P was not significant (NS) for all comparisons of NC versus AC. The SSS for LLk patients for NC versus AC were 0.51 +/- 1.0 versus 0.6 +/- 1.1, respectively; P was NS. The specificity for both NC and AC was 73%. The sensitivities for NC and AC were 80% and 81%, respectively, and the accuracies for NC and AC were 77% and 78%, respectively; P was NS for both comparisons. There are no significant diagnostic differences between automated quantitative MPS analyses performed in studies

WE-H-206-00: Advances in Preclinical Imaging

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

NONE

-modality imaging instrumentation and techniques that are being developed. Sang Hyun Cho; X-ray fluorescence (XRF) imaging, such as x-ray fluorescence computed tomography (XFCT), offers unique capabilities for accurate identification and quantification of metals within the imaging objects. As a result, it has emerged as a promising quantitative imaging modality in recent years, especially in conjunction with metal-based imaging probes. This talk will familiarize the audience with the basic principles of XRF/XFCT imaging. It will also cover the latest development of benchtop XFCT technology. Additionally, the use of metallic nanoparticles such as gold nanoparticles, in conjunction with benchtop XFCT, will be discussed within the context of preclinical multimodal multiplexed molecular imaging. Learning Objectives: To learn the basic principles of XRF/XFCT imaging To learn the latest advances in benchtop XFCT development for preclinical imaging Funding support received from NIH and DOD; Funding support received from GE Healthcare; Funding support received from Siemens AX; Patent royalties received from GE Healthcare; L. Wang, Funding Support: NIH; COI: Microphotoacoustics; S. Cho, Yes: ;NIH/NCI grant R01CA155446 DOD/PCRP grant W81XWH-12-1-0198.« less

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

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

Longitudinal Assessment of Lung Cancer Progression in Mice Using the Sodium Iodide Symporter Reporter Gene and SPECT/CT Imaging.

PubMed

Price, Dominique N; McBride, Amber A; Anton, Martina; Kusewitt, Donna F; Norenberg, Jeffrey P; MacKenzie, Debra A; Thompson, Todd A; Muttil, Pavan

2016-01-01

Lung cancer has the highest mortality rate of any tissue-specific cancer in both men and women. Research continues to investigate novel drugs and therapies to mitigate poor treatment efficacy, but the lack of a good descriptive lung cancer animal model for preclinical drug evaluation remains an obstacle. Here we describe the development of an orthotopic lung cancer animal model which utilizes the human sodium iodide symporter gene (hNIS; SLC5A5) as an imaging reporter gene for the purpose of non-invasive, longitudinal tumor quantification. hNIS is a glycoprotein that naturally transports iodide (I-) into thyroid cells and has the ability to symport the radiotracer 99mTc-pertechnetate (99mTcO4-). A549 lung adenocarcinoma cells were genetically modified with plasmid or lentiviral vectors to express hNIS. Modified cells were implanted into athymic nude mice to develop two tumor models: a subcutaneous and an orthotopic xenograft tumor model. Tumor progression was longitudinally imaged using SPECT/CT and quantified by SPECT voxel analysis. hNIS expression in lung tumors was analyzed by quantitative real-time PCR. Additionally, hematoxylin and eosin staining and visual inspection of pulmonary tumors was performed. We observed that lentiviral transduction provided enhanced and stable hNIS expression in A549 cells. Furthermore, 99mTcO4- uptake and accumulation was observed within lung tumors allowing for imaging and quantification of tumor mass at two-time points. This study illustrates the development of an orthotopic lung cancer model that can be longitudinally imaged throughout the experimental timeline thus avoiding inter-animal variability and leading to a reduction in total animal numbers. Furthermore, our orthotopic lung cancer animal model is clinically relevant and the genetic modification of cells for SPECT/CT imaging can be translated to other tissue-specific tumor animal models.

Longitudinal Assessment of Lung Cancer Progression in Mice Using the Sodium Iodide Symporter Reporter Gene and SPECT/CT Imaging

PubMed Central

Anton, Martina; Kusewitt, Donna F.; Norenberg, Jeffrey P.; MacKenzie, Debra A.; Thompson, Todd A.; Muttil, Pavan

2016-01-01

Lung cancer has the highest mortality rate of any tissue-specific cancer in both men and women. Research continues to investigate novel drugs and therapies to mitigate poor treatment efficacy, but the lack of a good descriptive lung cancer animal model for preclinical drug evaluation remains an obstacle. Here we describe the development of an orthotopic lung cancer animal model which utilizes the human sodium iodide symporter gene (hNIS; SLC5A5) as an imaging reporter gene for the purpose of non-invasive, longitudinal tumor quantification. hNIS is a glycoprotein that naturally transports iodide (I-) into thyroid cells and has the ability to symport the radiotracer 99mTc-pertechnetate (99mTcO4-). A549 lung adenocarcinoma cells were genetically modified with plasmid or lentiviral vectors to express hNIS. Modified cells were implanted into athymic nude mice to develop two tumor models: a subcutaneous and an orthotopic xenograft tumor model. Tumor progression was longitudinally imaged using SPECT/CT and quantified by SPECT voxel analysis. hNIS expression in lung tumors was analyzed by quantitative real-time PCR. Additionally, hematoxylin and eosin staining and visual inspection of pulmonary tumors was performed. We observed that lentiviral transduction provided enhanced and stable hNIS expression in A549 cells. Furthermore, 99mTcO4- uptake and accumulation was observed within lung tumors allowing for imaging and quantification of tumor mass at two-time points. This study illustrates the development of an orthotopic lung cancer model that can be longitudinally imaged throughout the experimental timeline thus avoiding inter-animal variability and leading to a reduction in total animal numbers. Furthermore, our orthotopic lung cancer animal model is clinically relevant and the genetic modification of cells for SPECT/CT imaging can be translated to other tissue-specific tumor animal models. PMID:28036366

Utility of Quantitative Parameters from Single-Photon Emission Computed Tomography/Computed Tomography in Patients with Destructive Thyroiditis.

PubMed

Kim, Ji-Young; Kim, Ji Hyun; Moon, Jae Hoon; Kim, Kyoung Min; Oh, Tae Jung; Lee, Dong-Hwa; So, Young; Lee, Won Woo

2018-01-01

Quantitative parameters from Tc-99m pertechnetate single-photon emission computed tomography/computed tomography (SPECT/CT) are emerging as novel diagnostic markers for functional thyroid diseases. We intended to assess the utility of SPECT/CT parameters in patients with destructive thyroiditis. Thirty-five destructive thyroiditis patients (7 males and 28 females; mean age, 47.3 ± 13.0 years) and 20 euthyroid patients (6 males and 14 females; mean age, 45.0 ± 14.8 years) who underwent Tc-99m pertechnetate quantitative SPECT/CT were retrospectively enrolled. Quantitative parameters from the SPECT/CT (%uptake, standardized uptake value [SUV], thyroid volume, and functional thyroid mass [SUVmean × thyroid volume]) and thyroid hormone levels were investigated to assess correlations and predict the prognosis for destructive thyroiditis. The occurrence of hypothyroidism was the outcome for prognosis. All the SPECT/CT quantitative parameters were significantly lower in the 35 destructive thyroiditis patients compared to the 20 euthyroid patients using the same SPECT/CT scanner and protocol ( p < 0.001 for all parameters). T3 and free T4 did not correlate with any SPECT/CT parameters, but thyroid-stimulating hormone (TSH) significantly correlated with %uptake ( p = 0.004), SUVmean ( p < 0.001), SUVmax ( p = 0.002), and functional thyroid mass ( p < 0.001). Of the 35 destructive thyroiditis patients, 16 progressed to hypothyroidism. On univariate and multivariate analyses, only T3 levels were associated with the later occurrence of hypothyroidism ( p = 0.002, exp(β) = 1.022, 95% confidence interval: 1.008 - 1.035). Novel quantitative SPECT/CT parameters could discriminate patients with destructive thyroiditis from euthyroid patients, suggesting the robustness of the quantitative SPECT/CT approach. However, disease progression of destructive thyroiditis could not be predicted using the parameters, as these only correlated with TSH, but not with T3, the sole predictor of

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.

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.

A method for energy window optimization for quantitative tasks that includes the effects of model-mismatch on bias: application to Y-90 bremsstrahlung SPECT imaging.

PubMed

Rong, Xing; Du, Yong; Frey, Eric C

2012-06-21

Quantitative Yttrium-90 ((90)Y) bremsstrahlung single photon emission computed tomography (SPECT) imaging has shown great potential to provide reliable estimates of (90)Y activity distribution for targeted radionuclide therapy dosimetry applications. One factor that potentially affects the reliability of the activity estimates is the choice of the acquisition energy window. In contrast to imaging conventional gamma photon emitters where the acquisition energy windows are usually placed around photopeaks, there has been great variation in the choice of the acquisition energy window for (90)Y imaging due to the continuous and broad energy distribution of the bremsstrahlung photons. In quantitative imaging of conventional gamma photon emitters, previous methods for optimizing the acquisition energy window assumed unbiased estimators and used the variance in the estimates as a figure of merit (FOM). However, for situations, such as (90)Y imaging, where there are errors in the modeling of the image formation process used in the reconstruction there will be bias in the activity estimates. In (90)Y bremsstrahlung imaging this will be especially important due to the high levels of scatter, multiple scatter, and collimator septal penetration and scatter. Thus variance will not be a complete measure of reliability of the estimates and thus is not a complete FOM. To address this, we first aimed to develop a new method to optimize the energy window that accounts for both the bias due to model-mismatch and the variance of the activity estimates. We applied this method to optimize the acquisition energy window for quantitative (90)Y bremsstrahlung SPECT imaging in microsphere brachytherapy. Since absorbed dose is defined as the absorbed energy from the radiation per unit mass of tissues in this new method we proposed a mass-weighted root mean squared error of the volume of interest (VOI) activity estimates as the FOM. To calculate this FOM, two analytical expressions were

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

Quantitative single-photon emission computed tomography/computed tomography for technetium pertechnetate thyroid uptake measurement

PubMed Central

Lee, Hyunjong; Kim, Ji Hyun; Kang, Yeon-koo; Moon, Jae Hoon; So, Young; Lee, Won Woo

2016-01-01

Abstract Objectives: Technetium pertechnetate (99mTcO4) is a radioactive tracer used to assess thyroid function by thyroid uptake system (TUS). However, the TUS often fails to deliver accurate measurements of the percent of thyroid uptake (%thyroid uptake) of 99mTcO4. Here, we investigated the usefulness of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) after injection of 99mTcO4 in detecting thyroid function abnormalities. Materials and methods: We retrospectively reviewed data from 50 patients (male:female = 15:35; age, 46.2 ± 16.3 years; 17 Graves disease, 13 thyroiditis, and 20 euthyroid). All patients underwent 99mTcO4 quantitative SPECT/CT (185 MBq = 5 mCi), which yielded %thyroid uptake and standardized uptake value (SUV). Twenty-one (10 Graves disease and 11 thyroiditis) of the 50 patients also underwent conventional %thyroid uptake measurements using a TUS. Results: Quantitative SPECT/CT parameters (%thyroid uptake, SUVmean, and SUVmax) were the highest in Graves disease, second highest in euthyroid, and lowest in thyroiditis (P < 0.0001, Kruskal–Wallis test). TUS significantly overestimated the %thyroid uptake compared with SPECT/CT (P < 0.0001, paired t test) because other 99mTcO4 sources in addition to thyroid, such as salivary glands and saliva, contributed to the %thyroid uptake result by TUS, whereas %thyroid uptake, SUVmean and SUVmax from the SPECT/CT were associated with the functional status of thyroid. Conclusions: Quantitative SPECT/CT is more accurate than conventional TUS for measuring 99mTcO4 %thyroid uptake. Quantitative measurements using SPECT/CT may facilitate more accurate assessment of thyroid tracer uptake. PMID:27399139

Validation of Left Ventricular Ejection Fraction with the IQ•SPECT System in Small-Heart Patients.

PubMed

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

2017-09-01

The IQ•SPECT system, which is equipped with multifocal collimators ( SMART ZOOM) and uses ordered-subset conjugate gradient minimization as the reconstruction algorithm, reduces the acquisition time of myocardial perfusion imaging compared with conventional SPECT systems equipped with low-energy high-resolution collimators. We compared the IQ•SPECT system with a conventional SPECT system for estimating left ventricular ejection fraction (LVEF) in patients with a small heart (end-systolic volume < 20 mL). Methods: The study consisted of 98 consecutive patients who underwent a 1-d stress-rest myocardial perfusion imaging study with a 99m Tc-labeled agent for preoperative risk assessment. Data were reconstructed using filtered backprojection for conventional SPECT and ordered-subset conjugate gradient minimization for IQ•SPECT. End-systolic volume, end-diastolic volume, and LVEF were calculated using quantitative gated SPECT (QGS) and cardioREPO software. We compared the LVEF from gated myocardial perfusion SPECT to that from echocardiographic measurements. Results: End-diastolic volume, end-systolic volume, and LVEF as obtained from conventional SPECT, IQ•SPECT, and echocardiography showed a good to excellent correlation regardless of whether they were calculated using QGS or using cardioREPO. Although LVEF calculated using QGS significantly differed between conventional SPECT and IQ•SPECT (65.4% ± 13.8% vs. 68.4% ± 15.2%) ( P = 0.0002), LVEF calculated using cardioREPO did not (69.5% ± 10.6% vs. 69.5% ± 11.0%). Likewise, although LVEF calculated using QGS significantly differed between conventional SPECT and IQ•SPECT (75.0 ± 9.6 vs. 79.5 ± 8.3) ( P = 0.0005), LVEF calculated using cardioREPO did not (72.3% ± 9.0% vs. 74.3% ± 8.3%). Conclusion: In small-heart patients, the difference in LVEF between IQ•SPECT and conventional SPECT was less when calculated using cardioREPO than when calculated using QGS. © 2017 by the Society of Nuclear Medicine

Realistic simulated MRI and SPECT databases. Application to SPECT/MRI registration evaluation.

PubMed

Aubert-Broche, Berengere; Grova, Christophe; Reilhac, Anthonin; Evans, Alan C; Collins, D Louis

2006-01-01

This paper describes the construction of simulated SPECT and MRI databases that account for realistic anatomical and functional variability. The data is used as a gold-standard to evaluate four SPECT/MRI similarity-based registration methods. Simulation realism was accounted for using accurate physical models of data generation and acquisition. MRI and SPECT simulations were generated from three subjects to take into account inter-subject anatomical variability. Functional SPECT data were computed from six functional models of brain perfusion. Previous models of normal perfusion and ictal perfusion observed in Mesial Temporal Lobe Epilepsy (MTLE) were considered to generate functional variability. We studied the impact noise and intensity non-uniformity in MRI simulations and SPECT scatter correction may have on registration accuracy. We quantified the amount of registration error caused by anatomical and functional variability. Registration involving ictal data was less accurate than registration involving normal data. MR intensity nonuniformity was the main factor decreasing registration accuracy. The proposed simulated database is promising to evaluate many functional neuroimaging methods, involving MRI and SPECT data.

Utility of Quantitative Parameters from Single-Photon Emission Computed Tomography/Computed Tomography in Patients with Destructive Thyroiditis

PubMed Central

Kim, Ji-Young; Kim, Ji Hyun; Moon, Jae Hoon; Kim, Kyoung Min; Oh, Tae Jung; Lee, Dong-Hwa; So, Young

2018-01-01

Objective Quantitative parameters from Tc-99m pertechnetate single-photon emission computed tomography/computed tomography (SPECT/CT) are emerging as novel diagnostic markers for functional thyroid diseases. We intended to assess the utility of SPECT/CT parameters in patients with destructive thyroiditis. Materials and Methods Thirty-five destructive thyroiditis patients (7 males and 28 females; mean age, 47.3 ± 13.0 years) and 20 euthyroid patients (6 males and 14 females; mean age, 45.0 ± 14.8 years) who underwent Tc-99m pertechnetate quantitative SPECT/CT were retrospectively enrolled. Quantitative parameters from the SPECT/CT (%uptake, standardized uptake value [SUV], thyroid volume, and functional thyroid mass [SUVmean × thyroid volume]) and thyroid hormone levels were investigated to assess correlations and predict the prognosis for destructive thyroiditis. The occurrence of hypothyroidism was the outcome for prognosis. Results All the SPECT/CT quantitative parameters were significantly lower in the 35 destructive thyroiditis patients compared to the 20 euthyroid patients using the same SPECT/CT scanner and protocol (p < 0.001 for all parameters). T3 and free T4 did not correlate with any SPECT/CT parameters, but thyroid-stimulating hormone (TSH) significantly correlated with %uptake (p = 0.004), SUVmean (p < 0.001), SUVmax (p = 0.002), and functional thyroid mass (p < 0.001). Of the 35 destructive thyroiditis patients, 16 progressed to hypothyroidism. On univariate and multivariate analyses, only T3 levels were associated with the later occurrence of hypothyroidism (p = 0.002, exp(β) = 1.022, 95% confidence interval: 1.008 – 1.035). Conclusion Novel quantitative SPECT/CT parameters could discriminate patients with destructive thyroiditis from euthyroid patients, suggesting the robustness of the quantitative SPECT/CT approach. However, disease progression of destructive thyroiditis could not be predicted using the parameters, as these only correlated

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

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

Recommendations for Benchmarking Preclinical Studies of Nanomedicines.

PubMed

Dawidczyk, Charlene M; Russell, Luisa M; Searson, Peter C

2015-10-01

Nanoparticle-based delivery systems provide new opportunities to overcome the limitations associated with traditional small-molecule drug therapy for cancer and to achieve both therapeutic and diagnostic functions in the same platform. Preclinical trials are generally designed to assess therapeutic potential and not to optimize the design of the delivery platform. Consequently, progress in developing design rules for cancer nanomedicines has been slow, hindering progress in the field. Despite the large number of preclinical trials, several factors restrict comparison and benchmarking of different platforms, including variability in experimental design, reporting of results, and the lack of quantitative data. To solve this problem, we review the variables involved in the design of preclinical trials and propose a protocol for benchmarking that we recommend be included in in vivo preclinical studies of drug-delivery platforms for cancer therapy. This strategy will contribute to building the scientific knowledge base that enables development of design rules and accelerates the translation of new technologies. ©2015 American Association for Cancer Research.

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.

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.

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.

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

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.

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

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

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.

Performance evaluation of D-SPECT: a novel SPECT system for nuclear cardiology

NASA Astrophysics Data System (ADS)

Erlandsson, Kjell; Kacperski, Krzysztof; van Gramberg, Dean; Hutton, Brian F.

2009-05-01

D-SPECT (Spectrum Dynamics, Israel) is a novel SPECT system for cardiac perfusion studies. Based on CZT detectors, region-centric scanning, high-sensitivity collimators and resolution recovery, it offers potential advantages over conventional systems. A series of measurements were made on a β-version D-SPECT system in order to evaluate its performance in terms of energy resolution, scatter fraction, sensitivity, count rate capability and resolution. Corresponding measurements were also done on a conventional SPECT system (CS) for comparison. The energy resolution of the D-SPECT system at 140 keV was 5.5% (CS: 9.25%), the scatter fraction 30% (CS: 34%), the planar sensitivity 398 s-1 MBq-1 per head (99mTc, 10 cm) (CS: 72 s-1 MBq-1), and the tomographic sensitivity in the heart region was in the range 647-1107 s-1 MBq-1 (CS: 141 s-1 MBq-1). The count rate increased linearly with increasing activity up to 1.44 M s-1. The intrinsic resolution was equal to the pixel size, 2.46 mm (CS: 3.8 mm). The average reconstructed resolution using the standard clinical filter was 12.5 mm (CS: 13.7 mm). The D-SPECT has superior sensitivity to that of a conventional system with similar spatial resolution. It also has excellent energy resolution and count rate characteristics, which should prove useful in dynamic and dual radionuclide studies.

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.

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.

Image-based informatics for Preclinical Biomedical Research

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

Tobin Jr, Kenneth William; Aykac, Deniz; Price, Jeffery R

2006-01-01

In 2006, the New England Journal of Medicine selected medical imaging as one of the eleven most important innovations of the past 1,000 years, primarily due to its ability to allow physicians and researchers to visualize the very nature of disease. As a result of the broad-based adoption of micro imaging technologies, preclinical researchers today are generating terabytes of image data from both anatomic and functional imaging modes. In this paper we describe our early research to apply content-based image retrieval to index and manage large image libraries generated in the study of amyloid disease in mice. Amyloidosis is associatedmore » with diseases such as Alzheimer's, type 2 diabetes, and myeloma. In particular, we will focus on results to date in the area of small animal organ segmentation and description for CT, SPECT, and PET modes and present a small set of preliminary retrieval results for a specific disease state in kidney CT cross-sections.« less

Image-based Informatics for Preclinical Biomedical Research

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

Tobin Jr, Kenneth William; Aykac, Deniz; Muthusamy Govindasamy, Vijaya Priya

2006-01-01

In 2006, the New England Journal of Medicine selected medical imaging as one of the eleven most important innovations of the past 1,000 years, primarily due to its ability to allow physicians and researchers to visualize the very nature of disease. As a result of the broad-based adoption of micro imaging technologies, preclinical researchers today are generating terabytes of image data from both anatomic and functional imaging modes. In this paper we describe our early research to apply content-based image retrieval to index and manage large image libraries generated in the study of amyloid disease in mice. Amyloidosis is associatedmore » with diseases such as Alzheimer's, type 2 diabetes, chronic inflammation and myeloma. In particular, we will focus on results to date in the area of small animal organ segmentation and description for CT, SPECT, and PET modes and present a small set of preliminary retrieval results for a specific disease state in kidney CT crosssections.« less

Brain perfusion SPECT in the mouse: normal pattern according to gender and age.

PubMed

Apostolova, Ivayla; Wunder, Andreas; Dirnagl, Ulrich; Michel, Roger; Stemmer, Nina; Lukas, Mathias; Derlin, Thorsten; Gregor-Mamoudou, Betina; Goldschmidt, Jürgen; Brenner, Winfried; Buchert, Ralph

2012-12-01

.7%, p=0.000) and at young adult age (AI=2.4 ± 1.7%, p=0.000). Gender had no effect on asymmetry. Voxel-wise testing confirmed the ROI-based findings. In conclusion, high-resolution HMPAO SPECT is a promising technique for measuring rCBF in preclinical research. It indicates lateral asymmetry of rCBF in the mouse brain as well as age-related changes during late maturation. ECD is not suitable as tracer for brain SPECT in the mouse because of its fast clearance from tissue indicating an interspecies difference in esterase activity between mice and humans. Copyright © 2012 Elsevier Inc. All rights reserved.

Design of a short nonuniform acquisition protocol for quantitative analysis in dynamic cardiac SPECT imaging - a retrospective 123 I-MIBG animal study.

PubMed

Zan, Yunlong; Long, Yong; Chen, Kewei; Li, Biao; Huang, Qiu; Gullberg, Grant T

2017-07-01

Our previous works have found that quantitative analysis of 123 I-MIBG kinetics in the rat heart with dynamic single-photon emission computed tomography (SPECT) offers the potential to quantify the innervation integrity at an early stage of left ventricular hypertrophy. However, conventional protocols involving a long acquisition time for dynamic imaging reduce the animal survival rate and thus make longitudinal analysis difficult. The goal of this work was to develop a procedure to reduce the total acquisition time by selecting nonuniform acquisition times for projection views while maintaining the accuracy and precision of estimated physiologic parameters. Taking dynamic cardiac imaging with 123 I-MIBG in rats as an example, we generated time activity curves (TACs) of regions of interest (ROIs) as ground truths based on a direct four-dimensional reconstruction of experimental data acquired from a rotating SPECT camera, where TACs represented as the coefficients of B-spline basis functions were used to estimate compartmental model parameters. By iteratively adjusting the knots (i.e., control points) of B-spline basis functions, new TACs were created according to two rules: accuracy and precision. The accuracy criterion allocates the knots to achieve low relative entropy between the estimated left ventricular blood pool TAC and its ground truth so that the estimated input function approximates its real value and thus the procedure yields an accurate estimate of model parameters. The precision criterion, via the D-optimal method, forces the estimated parameters to be as precise as possible, with minimum variances. Based on the final knots obtained, a new protocol of 30 min was built with a shorter acquisition time that maintained a 5% error in estimating rate constants of the compartment model. This was evaluated through digital simulations. The simulation results showed that our method was able to reduce the acquisition time from 100 to 30 min for the cardiac study

Imaging technologies for preclinical models of bone and joint disorders

PubMed Central

2011-01-01

Preclinical models for musculoskeletal disorders are critical for understanding the pathogenesis of bone and joint disorders in humans and the development of effective therapies. The assessment of these models primarily relies on morphological analysis which remains time consuming and costly, requiring large numbers of animals to be tested through different stages of the disease. The implementation of preclinical imaging represents a keystone in the refinement of animal models allowing longitudinal studies and enabling a powerful, non-invasive and clinically translatable way for monitoring disease progression in real time. Our aim is to highlight examples that demonstrate the advantages and limitations of different imaging modalities including magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and optical imaging. All of which are in current use in preclinical skeletal research. MRI can provide high resolution of soft tissue structures, but imaging requires comparatively long acquisition times; hence, animals require long-term anaesthesia. CT is extensively used in bone and joint disorders providing excellent spatial resolution and good contrast for bone imaging. Despite its excellent structural assessment of mineralized structures, CT does not provide in vivo functional information of ongoing biological processes. Nuclear medicine is a very promising tool for investigating functional and molecular processes in vivo with new tracers becoming available as biomarkers. The combined use of imaging modalities also holds significant potential for the assessment of disease pathogenesis in animal models of musculoskeletal disorders, minimising the use of conventional invasive methods and animal redundancy. PMID:22214535

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

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.

Perspective: Recommendations for benchmarking pre-clinical studies of nanomedicines

PubMed Central

Dawidczyk, Charlene M.; Russell, Luisa M.; Searson, Peter C.

2015-01-01

Nanoparticle-based delivery systems provide new opportunities to overcome the limitations associated with traditional small molecule drug therapy for cancer, and to achieve both therapeutic and diagnostic functions in the same platform. Pre-clinical trials are generally designed to assess therapeutic potential and not to optimize the design of the delivery platform. Consequently, progress in developing design rules for cancer nanomedicines has been slow, hindering progress in the field. Despite the large number of pre-clinical trials, several factors restrict comparison and benchmarking of different platforms, including variability in experimental design, reporting of results, and the lack of quantitative data. To solve this problem, we review the variables involved in the design of pre-clinical trials and propose a protocol for benchmarking that we recommend be included in in vivo pre-clinical studies of drug delivery platforms for cancer therapy. This strategy will contribute to building the scientific knowledge base that enables development of design rules and accelerates the translation of new technologies. PMID:26249177

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

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.

Non-invasive molecular imaging for preclinical cancer therapeutic development

PubMed Central

O'Farrell, AC; Shnyder, SD; Marston, G; Coletta, PL; Gill, JH

2013-01-01

Molecular and non-invasive imaging are rapidly emerging fields in preclinical cancer drug discovery. This is driven by the need to develop more efficacious and safer treatments, the advent of molecular-targeted therapeutics, and the requirements to reduce and refine current preclinical in vivo models. Such bioimaging strategies include MRI, PET, single positron emission computed tomography, ultrasound, and optical approaches such as bioluminescence and fluorescence imaging. These molecular imaging modalities have several advantages over traditional screening methods, not least the ability to quantitatively monitor pharmacodynamic changes at the cellular and molecular level in living animals non-invasively in real time. This review aims to provide an overview of non-invasive molecular imaging techniques, highlighting the strengths, limitations and versatility of these approaches in preclinical cancer drug discovery and development. PMID:23488622

Preclinical QSP Modeling in the Pharmaceutical Industry: An IQ Consortium Survey Examining the Current Landscape

PubMed Central

Wu, Fan; Bansal, Loveleena; Bradshaw‐Pierce, Erica; Chan, Jason R.; Liederer, Bianca M.; Mettetal, Jerome T.; Schroeder, Patricia; Schuck, Edgar; Tsai, Alice; Xu, Christine; Chimalakonda, Anjaneya; Le, Kha; Penney, Mark; Topp, Brian; Yamada, Akihiro

2018-01-01

A cross‐industry survey was conducted to assess the landscape of preclinical quantitative systems pharmacology (QSP) modeling within pharmaceutical companies. This article presents the survey results, which provide insights on the current state of preclinical QSP modeling in addition to future opportunities. Our results call attention to the need for an aligned definition and consistent terminology around QSP, yet highlight the broad applicability and benefits preclinical QSP modeling is currently delivering. PMID:29349875

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

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

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

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.

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.

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

Radiopharmaceuticals for SPECT cancer detection

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

Chernov, V. I., E-mail: chernov@oncology.tomsk.ru; Medvedeva, A. A., E-mail: tickayaAA@oncology.tomsk.ru; Zelchan, R. V., E-mail: r.zelchan@yandex.ru

2016-08-02

The purpose of the study was to assess the efficacy of single photon emission computed tomography (SPECT) with {sup 199}Tl and {sup 99}mTc-MIBI in the detection of breast, laryngeal and hypopharyngeal cancers. A total of 220 patients were included into the study: 120 patients with breast lesions (100 patients with breast cancer and 20 patients with benign breast tumors) and 100 patients with laryngeal/hypopharyngeal diseases (80 patients with laryngeal/hypopharyngeal cancer and 20 patients with benign laryngeal/hypopharyngeal lesions). No abnormal {sup 199}Tl uptake was seen in all patients with benign breast and laryngeal lesions, indicating a 100% specificity of {sup 199}Tlmore » SPECT. In the breast cancer patients, the increased {sup 199}Tl uptake in the breast was visualized in 94.8% patients, {sup 99m}Tc-MIBI—in 93.4% patients. The increased {sup 199}Tl uptake in axillary lymph nodes was detected in 60% patients, and {sup 99m}Tc-MIBI—in 93.1% patients. In patients with laryngeal/hypopharyngeal cancer, the sensitivity of SPECT with {sup 199}Tl and {sup 99m}Tc-MIBI was 95%. The {sup 199}Tl SPECT sensitivity in identification of regional lymph node metastases in the patients with laryngeal/hypopharyngeal cancer was 75% and the {sup 99m}Tc-MIBI SPECT sensitivity was 17%. The data obtained showed that SPECT with {sup 199}Tl and {sup 99m}Tc-MIBI can be used as one of the additional imaging methods in detection of tumors.« less

Quantitation of specific binding ratio in 123I-FP-CIT SPECT: accurate processing strategy for cerebral ventricular enlargement with use of 3D-striatal digital brain phantom.

PubMed

Furuta, Akihiro; Onishi, Hideo; Amijima, Hizuru

2018-06-01

This study aimed to evaluate the effect of ventricular enlargement on the specific binding ratio (SBR) and to validate the cerebrospinal fluid (CSF)-Mask algorithm for quantitative SBR assessment of 123 I-FP-CIT single-photon emission computed tomography (SPECT) images with the use of a 3D-striatum digital brain (SDB) phantom. Ventricular enlargement was simulated by three-dimensional extensions in a 3D-SDB phantom comprising segments representing the striatum, ventricle, brain parenchyma, and skull bone. The Evans Index (EI) was measured in 3D-SDB phantom images of an enlarged ventricle. Projection data sets were generated from the 3D-SDB phantoms with blurring, scatter, and attenuation. Images were reconstructed using the ordered subset expectation maximization (OSEM) algorithm and corrected for attenuation, scatter, and resolution recovery. We bundled DaTView (Southampton method) with the CSF-Mask processing software for SBR. We assessed SBR with the use of various coefficients (f factor) of the CSF-Mask. Specific binding ratios of 1, 2, 3, 4, and 5 corresponded to SDB phantom simulations with true values. Measured SBRs > 50% that were underestimated with EI increased compared with the true SBR and this trend was outstanding at low SBR. The CSF-Mask improved 20% underestimates and brought the measured SBR closer to the true values at an f factor of 1.0 despite an increase in EI. We connected the linear regression function (y = - 3.53x + 1.95; r = 0.95) with the EI and f factor using root-mean-square error. Processing with CSF-Mask generates accurate quantitative SBR from dopamine transporter SPECT images of patients with ventricular enlargement.

A prospective evaluation of the repeatability of left ventricular ejection fraction measurement by gated SPECT.

PubMed

Kliner, Dustin; Wang, Li; Winger, Daniel; Follansbee, William P; Soman, Prem

2015-12-01

Gated single-photon emission computed tomography (SPECT) is widely used for myocardial perfusion imaging and provides an automated assessment of left ventricular ejection fraction (LVEF). We prospectively tested the repeatability of serial SPECT-derived LVEF. This information is essential in order to inform the interpretation of a change in LV function on serial testing. Consenting patients (n = 50) from among those referred for clinically indicated gated myocardial perfusion SPECT (MPs) were recruited. Following the clinical rest-stress study, patients were repositioned on the camera table for a second acquisition using identical parameters. Patient positioning, image acquisition and processing for the second scan were independently performed by a technologist blinded to the clinical scan. Quantitative LVEF was generated by Quantitative Gated SPECT and recorded as EF1 and EF2, respectively. Repeatability of serial results was assessed using the Bland-Altman method. The limits of repeatability and repeatability coefficients were generated to determine the maximum variation in LVEF that can be expected to result from test variability. Repeatability was tested across a broad range of LV systolic function and myocardial perfusion. The mean difference between EF1 and EF2 was 1.6% (EF units), with 95% limits of repeatability of +9.1% to -6.0% (repeatability coefficient 7.5%). Correlation between serial EF measurements was excellent (r = 0.9809). Similar results were obtained in subgroups based on normal or abnormal EF and myocardial perfusion. The largest repeatability coefficient of 8.1% was seen in patients with abnormal LV systolic function. When test protocol and acquisition parameters are kept constant, a difference of >8% EF units on serial MPs is indicative of a true change 95% of the time.

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.

Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high efficiency SPECT

PubMed Central

Brodov, Yafim; Fish, Mathews; Rubeaux, Mathieu; Otaki, Yuka; Gransar, Heidi; Lemley, Mark; Gerlach, Jim; Berman, Daniel; Germano, Guido; Slomka, Piotr

2016-01-01

Background Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT. Methods Fifty patients (mean age 69 y) undergoing regadenoson same-day rest (8–11 mCi)/stress (32–42mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started one min after sequential intravenous regadenoson 0.4mg and Tc-99m injection, and was composed of five 2 min supine gated acquisitions followed by two 4 min supine and upright images. Ischemic total perfusion deficit (ITPD) ≥ 5 % was considered as significant ischemia. Results Significantly lower mean EF reserve was obtained in the 5th and 9th min after regadenoson bolus in patients with significant ischemia versus patients without (5th min: −4.2 ± 4.6% vs. 1.3 ± 6.6%, p = 0.006; 9th min: −2.7 ± 4.8% vs. 2.0 ± 6.6%, p = 0.03). Conclusions Negative EF reserve obtained between 5th and 9th min of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of myocardial stunning with Tc-99m HE-SPECT. PMID:27387521

Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high-efficiency SPECT.

PubMed

Brodov, Yafim; Fish, Mathews; Rubeaux, Mathieu; Otaki, Yuka; Gransar, Heidi; Lemley, Mark; Gerlach, Jim; Berman, Daniel; Germano, Guido; Slomka, Piotr

2016-12-01

Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT. Fifty patients (mean age 69 years) undergoing regadenoson same-day rest (8-11 mCi)/stress (32-42 mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started 1 minute after sequential intravenous regadenoson .4 mg and Tc-99m injections, and was composed of five 2 minutes supine gated acquisitions followed by two 4 minutes supine and upright images. Ischemic total perfusion deficit (ITPD) ≥5 % was considered as significant ischemia. Significantly lower mean EF reserve was obtained in the 5th and 9th minute after regadenoson bolus in patients with significant ischemia vs patients without (5th minute: -4.2 ± 4.6% vs 1.3 ± 6.6%, P = .006; 9th minute: -2.7 ± 4.8% vs 2.0 ± 6.6%, P = .03). Negative EF reserve obtained between 5th and 9th minutes of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of transient ischemic functional changes with Tc-99m HE-SPECT.

An automated voxelized dosimetry tool for radionuclide therapy based on serial quantitative SPECT/CT imaging

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

Jackson, Price A.; Kron, Tomas; Beauregard, Jean-Mathieu

2013-11-15

Purpose: To create an accurate map of the distribution of radiation dose deposition in healthy and target tissues during radionuclide therapy.Methods: Serial quantitative SPECT/CT images were acquired at 4, 24, and 72 h for 28 {sup 177}Lu-octreotate peptide receptor radionuclide therapy (PRRT) administrations in 17 patients with advanced neuroendocrine tumors. Deformable image registration was combined with an in-house programming algorithm to interpolate pharmacokinetic uptake and clearance at a voxel level. The resultant cumulated activity image series are comprised of values representing the total number of decays within each voxel's volume. For PRRT, cumulated activity was translated to absorbed dose basedmore » on Monte Carlo-determined voxel S-values at a combination of long and short ranges. These dosimetric image sets were compared for mean radiation absorbed dose to at-risk organs using a conventional MIRD protocol (OLINDA 1.1).Results: Absorbed dose values to solid organs (liver, kidneys, and spleen) were within 10% using both techniques. Dose estimates to marrow were greater using the voxelized protocol, attributed to the software incorporating crossfire effect from nearby tumor volumes.Conclusions: The technique presented offers an efficient, automated tool for PRRT dosimetry based on serial post-therapy imaging. Following retrospective analysis, this method of high-resolution dosimetry may allow physicians to prescribe activity based on required dose to tumor volume or radiation limits to healthy tissue in individual patients.« less

Segmentation and Visual Analysis of Whole-Body Mouse Skeleton microSPECT

PubMed Central

Khmelinskii, Artem; Groen, Harald C.; Baiker, Martin; de Jong, Marion; Lelieveldt, Boudewijn P. F.

2012-01-01

Whole-body SPECT small animal imaging is used to study cancer, and plays an important role in the development of new drugs. Comparing and exploring whole-body datasets can be a difficult and time-consuming task due to the inherent heterogeneity of the data (high volume/throughput, multi-modality, postural and positioning variability). The goal of this study was to provide a method to align and compare side-by-side multiple whole-body skeleton SPECT datasets in a common reference, thus eliminating acquisition variability that exists between the subjects in cross-sectional and multi-modal studies. Six whole-body SPECT/CT datasets of BALB/c mice injected with bone targeting tracers 99mTc-methylene diphosphonate (99mTc-MDP) and 99mTc-hydroxymethane diphosphonate (99mTc-HDP) were used to evaluate the proposed method. An articulated version of the MOBY whole-body mouse atlas was used as a common reference. Its individual bones were registered one-by-one to the skeleton extracted from the acquired SPECT data following an anatomical hierarchical tree. Sequential registration was used while constraining the local degrees of freedom (DoFs) of each bone in accordance to the type of joint and its range of motion. The Articulated Planar Reformation (APR) algorithm was applied to the segmented data for side-by-side change visualization and comparison of data. To quantitatively evaluate the proposed algorithm, bone segmentations of extracted skeletons from the correspondent CT datasets were used. Euclidean point to surface distances between each dataset and the MOBY atlas were calculated. The obtained results indicate that after registration, the mean Euclidean distance decreased from 11.5±12.1 to 2.6±2.1 voxels. The proposed approach yielded satisfactory segmentation results with minimal user intervention. It proved to be robust for “incomplete” data (large chunks of skeleton missing) and for an intuitive exploration and comparison of multi-modal SPECT/CT cross

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

Coronary Artery Disease: Analysis of Diagnostic Performance of CT Perfusion and MR Perfusion Imaging in Comparison with Quantitative Coronary Angiography and SPECT-Multicenter Prospective Trial.

PubMed

Rief, Matthias; Chen, Marcus Y; Vavere, Andrea L; Kendziora, Benjamin; Miller, Julie M; Bandettini, W Patricia; Cox, Christopher; George, Richard T; Lima, João; Di Carli, Marcelo; Plotkin, Michail; Zimmermann, Elke; Laule, Michael; Schlattmann, Peter; Arai, Andrew E; Dewey, Marc

2018-02-01

Purpose To compare the diagnostic performance of stress myocardial computed tomography (CT) perfusion with that of stress myocardial magnetic resonance (MR) perfusion imaging in the detection of coronary artery disease (CAD). Materials and Methods All patients gave written informed consent prior to inclusion in this institutional review board-approved study. This two-center substudy of the prospective Combined Noninvasive Coronary Angiography and Myocardial Perfusion Imaging Using 320-Detector Row Computed Tomography (CORE320) multicenter trial included 92 patients (mean age, 63.1 years ± 8.1 [standard deviation]; 73% male). All patients underwent perfusion CT and perfusion MR imaging with either adenosine or regadenoson stress. The predefined reference standards were combined quantitative coronary angiography (QCA) and single-photon emission CT (SPECT) or QCA alone. Results from coronary CT angiography were not included, and diagnostic performance was evaluated with the Mantel-Haenszel test stratified by disease status. Results The prevalence of CAD was 39% (36 of 92) according to QCA and SPECT and 64% (59 of 92) according to QCA alone. When compared with QCA and SPECT, per-patient diagnostic accuracy of perfusion CT and perfusion MR imaging was 63% (58 of 92) and 75% (69 of 92), respectively (P = .11); sensitivity was 92% (33 of 36) and 83% (30 of 36), respectively (P = .45); and specificity was 45% (25 of 56) and 70% (39 of 56), respectively (P < .01). When compared with QCA alone, diagnostic accuracy of CT perfusion and MR perfusion imaging was 82% (75 of 92) and 74% (68 of 92), respectively (P = .27); sensitivity was 90% (53 of 59) and 69% (41 of 59), respectively (P < .01); and specificity was 67% (22 of 33) and 82% (27 of 33), respectively (P = .27). Conclusion This multicenter study shows that the diagnostic performance of perfusion CT is similar to that of perfusion MR imaging in the detection of CAD. © RSNA, 2017 Online supplemental material is

Improvement of Cerebral Hypoperfusion with Levothyroxine Therapy in Hashimoto's Encephalopathy Demonstrated by 99mTc-HMPAO-SPECT

PubMed Central

Schnedl, Wolfgang J.; Mirzaei, Siroos; Wallner-Liebmann, Sandra J.; Tafeit, Erwin; Mangge, Harald; Krause, Robert; Lipp, Rainer W.

2013-01-01

Background Hashimoto's encephalopathy (HE) is a rare immune-mediated encephalopathy associated with autoimmune Hashimoto's thyroiditis. Objectives and Methods We report on a patient with HE and significant clinical improvement correlating with an increase in cerebral blood flow demonstrated by hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography (SPECT). HMPAO-SPECT was performed with 740 MBq of technetium-99m-HMPAO. To demonstrate the improvement in regional cerebral blood flow, individual regions of interest were drawn around visually diminished HMPAO uptake, the lesion to reference region ratio was calculated and transverse section images and semi-quantitative measurements were performed. Results We show a 5-year follow-up with significant clinical improvement, a 10-fold reduction in autoantibodies to thyroid peroxidase and an approximately 20% improvement in cerebral blood flow with HMPAO-SPECT. Conclusion Adequate levothyroxine treatment achieving and maintaining euthyroidism should be considered as therapy to lower autoantibodies and improve clinical outcome in patients with Hashimoto's thyroiditis and encephalopathy. PMID:24783049

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

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

Preclinical dose number and its application in understanding drug absorption risk and formulation design for preclinical species.

PubMed

Wuelfing, W Peter; Daublain, Pierre; Kesisoglou, Filippos; Templeton, Allen; McGregor, Caroline

2015-04-06

In the drug discovery setting, the ability to rapidly identify drug absorption risk in preclinical species at high doses from easily measured physical properties is desired. This is due to the large number of molecules being evaluated and their high attrition rate, which make resource-intensive in vitro and in silico evaluation unattractive. High-dose in vivo data from rat, dog, and monkey are analyzed here, using a preclinical dose number (PDo) concept based on the dose number described by Amidon and other authors (Pharm. Res., 1993, 10, 264-270). PDo, as described in this article, is simply calculated as dose (mg/kg) divided by compound solubility in FaSSIF (mg/mL) and approximates the volume of biorelevant media per kilogram of animal that would be needed to fully dissolve the dose. High PDo values were found to be predictive of difficulty in achieving drug exposure (AUC)-dose proportionality in in vivo studies, as could be expected; however, this work analyzes a large data set (>900 data points) and provides quantitative guidance to identify drug absorption risk in preclinical species based on a single solubility measurement commonly carried out in drug discovery. Above the PDo values defined, >50% of all in vivo studies exhibited poor AUC-dose proportionality in rat, dog, and monkey, and these values can be utilized as general guidelines in discovery and early development to rapidly assess risk of solubility-limited absorption for a given compound. A preclinical dose number generated by biorelevant dilutions of formulated compounds (formulated PDo) was also evaluated and defines solubility targets predictive of suitable AUC-dose proportionality in formulation development efforts. Application of these guidelines can serve to efficiently identify compounds in discovery that are likely to present extreme challenges with respect to solubility-limited absorption in preclinical species as well as reduce the testing of poor formulations in vivo, which is a key

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.

99mTc-CXCL8 SPECT to Monitor Disease Activity in Inflammatory Bowel Disease.

PubMed

Aarntzen, Erik H J G; Hermsen, Rick; Drenth, Joost P H; Boerman, Otto C; Oyen, Wim J G

2016-03-01

Inflammatory bowel diseases (IBDs) are defined as chronic relapsing immune-mediated disorders of the gastrointestinal tract. IBD exacerbations are characterized by recruitment of mainly CXCL8 receptor-expressing activated neutrophils into the intestinal wall, leading to severe damage. Considering its chronic relapsing character, accurate and timely diagnosis of an exacerbation is pivotal for early adaptation of the treatment and reduction of the disease burden. However, endoscopic evaluation is invasive and associated with an increased risk of perforation. We previously developed a (99m)Tc-labeled CXCL8 preparation in preclinical models including colitis and clinical studies. In this study, we investigate the accuracy of (99m)Tc-CXCL8 SPECT to detect and localize disease activity in a prospective series of patients with IBD. Thirty patients (15 Crohns disease, 15 ulcerative colitis) participated, and 92 segmental pairs of histology and (99m)Tc-CXCL8 scans were studied. Imaging was performed after injection of 400 MBq of (99m)Tc-CXCL8. Planar and SPECT images of the abdomen were acquired at 30 min and 4 h after the injection. The overall sensitivity and specificity on a per-patient basis for the detection of active disease were 95% and 44% for (99m)Tc-CXCL8 scan and 71% and 70% for endoscopy. The degree of (99m)Tc-CXCL8 accumulation correlated to the degree of neutrophilic influx in affected mucosa. Sensitivity and specificity on a per-segment basis, calculated from the 92 segmental pairs, were 82% and 72%, negative predictive value was 81%, and overall positive predictive value was 74%. Specificity could be increased at the expense of sensitivity using different cutoffs. In 74 segmental pairs, overall sensitivity and specificity for endoscopy were 74% and 85%, positive predictive value was 81%, and negative predictive value was 79%. (99m)Tc-CXCL8 SPECT provides a novel imaging technique to target neutrophil recruitment to the intestinal wall, especially in moderate

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.

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

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

Circulating Tumor Cell Analysis in Preclinical Mouse Models of Metastasis.

PubMed

Kitz, Jenna; Lowes, Lori E; Goodale, David; Allan, Alison L

2018-04-28

The majority of cancer deaths occur because of metastasis since current therapies are largely non-curative in the metastatic setting. The use of in vivo preclinical mouse models for assessing metastasis is, therefore, critical for developing effective new cancer biomarkers and therapies. Although a number of quantitative tools have been previously developed to study in vivo metastasis, the detection and quantification of rare metastatic events has remained challenging. This review will discuss the use of circulating tumor cell (CTC) analysis as an effective means of tracking and characterizing metastatic disease progression in preclinical mouse models of breast and prostate cancer and the resulting lessons learned about CTC and metastasis biology. We will also discuss how the use of clinically-relevant CTC technologies such as the CellSearch ® and Parsortix™ platforms for preclinical CTC studies can serve to enhance the study of cancer biology, new biomarkers, and novel therapies from the bench to the bedside.

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.

SPECT (Single-Photon Emission Computerized Tomography) Scan

MedlinePlus

... can become damaged or even die. Reduced pumping efficiency. SPECT can show how completely your heart chambers ... radioactive tracer SPECT scans aren't safe for women who are pregnant or breast-feeding because the ...

Three-dimensional ordered-subset expectation maximization iterative protocol for evaluation of left ventricular volumes and function by quantitative gated SPECT: a dynamic phantom study.

PubMed

Ceriani, Luca; Ruberto, Teresa; Delaloye, Angelika Bischof; Prior, John O; Giovanella, Luca

2010-03-01

The purposes of this study were to characterize the performance of a 3-dimensional (3D) ordered-subset expectation maximization (OSEM) algorithm in the quantification of left ventricular (LV) function with (99m)Tc-labeled agent gated SPECT (G-SPECT), the QGS program, and a beating-heart phantom and to optimize the reconstruction parameters for clinical applications. A G-SPECT image of a dynamic heart phantom simulating the beating left ventricle was acquired. The exact volumes of the phantom were known and were as follows: end-diastolic volume (EDV) of 112 mL, end-systolic volume (ESV) of 37 mL, and stroke volume (SV) of 75 mL; these volumes produced an LV ejection fraction (LVEF) of 67%. Tomographic reconstructions were obtained after 10-20 iterations (I) with 4, 8, and 16 subsets (S) at full width at half maximum (FWHM) gaussian postprocessing filter cutoff values of 8-15 mm. The QGS program was used for quantitative measurements. Measured values ranged from 72 to 92 mL for EDV, from 18 to 32 mL for ESV, and from 54 to 63 mL for SV, and the calculated LVEF ranged from 65% to 76%. Overall, the combination of 10 I, 8 S, and a cutoff filter value of 10 mm produced the most accurate results. The plot of the measures with respect to the expectation maximization-equivalent iterations (I x S product) revealed a bell-shaped curve for the LV volumes and a reverse distribution for the LVEF, with the best results in the intermediate range. In particular, FWHM cutoff values exceeding 10 mm affected the estimation of the LV volumes. The QGS program is able to correctly calculate the LVEF when used in association with an optimized 3D OSEM algorithm (8 S, 10 I, and FWHM of 10 mm) but underestimates the LV volumes. However, various combinations of technical parameters, including a limited range of I and S (80-160 expectation maximization-equivalent iterations) and low cutoff values (< or =10 mm) for the gaussian postprocessing filter, produced results with similar accuracies and

Novel Application of Quantitative Single-Photon Emission Computed Tomography/Computed Tomography to Predict Early Response to Methimazole in Graves' Disease

PubMed Central

Kim, Hyun Joo; Bang, Ji-In; Kim, Ji-Young; Moon, Jae Hoon; So, Young

2017-01-01

Objective Since Graves' disease (GD) is resistant to antithyroid drugs (ATDs), an accurate quantitative thyroid function measurement is required for the prediction of early responses to ATD. Quantitative parameters derived from the novel technology, single-photon emission computed tomography/computed tomography (SPECT/CT), were investigated for the prediction of achievement of euthyroidism after methimazole (MMI) treatment in GD. Materials and Methods A total of 36 GD patients (10 males, 26 females; mean age, 45.3 ± 13.8 years) were enrolled for this study, from April 2015 to January 2016. They underwent quantitative thyroid SPECT/CT 20 minutes post-injection of 99mTc-pertechnetate (5 mCi). Association between the time to biochemical euthyroidism after MMI treatment and %uptake, standardized uptake value (SUV), functional thyroid mass (SUVmean × thyroid volume) from the SPECT/CT, and clinical/biochemical variables, were investigated. Results GD patients had a significantly greater %uptake (6.9 ± 6.4%) than historical control euthyroid patients (n = 20, 0.8 ± 0.5%, p < 0.001) from the same quantitative SPECT/CT protocol. Euthyroidism was achieved in 14 patients at 156 ± 62 days post-MMI treatment, but 22 patients had still not achieved euthyroidism by the last follow-up time-point (208 ± 80 days). In the univariate Cox regression analysis, the initial MMI dose (p = 0.014), %uptake (p = 0.015), and functional thyroid mass (p = 0.016) were significant predictors of euthyroidism in response to MMI treatment. However, only %uptake remained significant in a multivariate Cox regression analysis (p = 0.034). A %uptake cutoff of 5.0% dichotomized the faster responding versus the slower responding GD patients (p = 0.006). Conclusion A novel parameter of thyroid %uptake from quantitative SPECT/CT is a predictive indicator of an early response to MMI in GD patients. PMID:28458607

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.

Development of a Spect-Based Three-Dimensional Treatment Planner for Radionuclide Therapy with Iodine -131.

NASA Astrophysics Data System (ADS)

Giap, Huan Bosco

Accurate calculation of absorbed dose to target tumors and normal tissues in the body is an important requirement for establishing fundamental dose-response relationships for radioimmunotherapy. Two major obstacles have been the difficulty in obtaining an accurate patient-specific 3-D activity map in-vivo and calculating the resulting absorbed dose. This study investigated a methodology for 3-D internal dosimetry, which integrates the 3-D biodistribution of the radionuclide acquired from SPECT with a dose-point kernel convolution technique to provide the 3-D distribution of absorbed dose. Accurate SPECT images were reconstructed with appropriate methods for noise filtering, attenuation correction, and Compton scatter correction. The SPECT images were converted into activity maps using a calibration phantom. The activity map was convolved with an ^{131}I dose-point kernel using a 3-D fast Fourier transform to yield a 3-D distribution of absorbed dose. The 3-D absorbed dose map was then processed to provide the absorbed dose distribution in regions of interest. This methodology can provide heterogeneous distributions of absorbed dose in volumes of any size and shape with nonuniform distributions of activity. Comparison of the activities quantitated by our SPECT methodology to true activities in an Alderson abdominal phantom (with spleen, liver, and spherical tumor) yielded errors of -16.3% to 4.4%. Volume quantitation errors ranged from -4.0 to 5.9% for volumes greater than 88 ml. The percentage differences of the average absorbed dose rates calculated by this methodology and the MIRD S-values were 9.1% for liver, 13.7% for spleen, and 0.9% for the tumor. Good agreement (percent differences were less than 8%) was found between the absorbed dose due to penetrating radiation calculated from this methodology and TLD measurement. More accurate estimates of the 3 -D distribution of absorbed dose can be used as a guide in specifying the minimum activity to be administered

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.

Quantitative pre-clinical screening of therapeutics for joint diseases using contrast enhanced micro-computed tomography.

PubMed

Willett, N J; Thote, T; Hart, M; Moran, S; Guldberg, R E; Kamath, R V

2016-09-01

The development of effective therapies for cartilage protection has been limited by a lack of efficient quantitative cartilage imaging modalities in pre-clinical in vivo models. Our objectives were two-fold: first, to validate a new contrast-enhanced 3D imaging analysis technique, equilibrium partitioning of an ionic contrast agent-micro computed tomography (EPIC-μCT), in a rat medial meniscal transection (MMT) osteoarthritis (OA) model; and second, to quantitatively assess the sensitivity of EPIC-μCT to detect the effects of matrix metalloproteinase inhibitor (MMPi) therapy on cartilage degeneration. Rats underwent MMT surgery and tissues were harvested at 1, 2, and 3 weeks post-surgery or rats received an MMPi or vehicle treatment and tissues harvested 3 weeks post-surgery. Parameters of disease progression were evaluated using histopathology and EPIC-μCT. Correlations and power analyses were performed to compare the techniques. EPIC-μCT was shown to provide simultaneous 3D quantification of multiple parameters, including cartilage degeneration and osteophyte formation. In MMT animals treated with MMPi, OA progression was attenuated, as measured by 3D parameters such as lesion volume and osteophyte size. A post-hoc power analysis showed that 3D parameters for EPIC-μCT were more sensitive than 2D parameters requiring fewer animals to detect a therapeutic effect of MMPi. 2D parameters were comparable between EPIC-μCT and histopathology. This study demonstrated that EPIC-μCT has high sensitivity to provide 3D structural and compositional measurements of cartilage and bone in the joint. EPIC-μCT can be used in combination with histology to provide a comprehensive analysis to screen new potential therapies. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

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

Review of SPECT collimator selection, optimization, and fabrication for clinical and preclinical imaging

PubMed Central

Van Audenhaege, Karen; Van Holen, Roel; Vandenberghe, Stefaan; Vanhove, Christian; Metzler, Scott D.; Moore, Stephen C.

2015-01-01

In single photon emission computed tomography, the choice of the collimator has a major impact on the sensitivity and resolution of the system. Traditional parallel-hole and fan-beam collimators used in clinical practice, for example, have a relatively poor sensitivity and subcentimeter spatial resolution, while in small-animal imaging, pinhole collimators are used to obtain submillimeter resolution and multiple pinholes are often combined to increase sensitivity. This paper reviews methods for production, sensitivity maximization, and task-based optimization of collimation for both clinical and preclinical imaging applications. New opportunities for improved collimation are now arising primarily because of (i) new collimator-production techniques and (ii) detectors with improved intrinsic spatial resolution that have recently become available. These new technologies are expected to impact the design of collimators in the future. The authors also discuss concepts like septal penetration, high-resolution applications, multiplexing, sampling completeness, and adaptive systems, and the authors conclude with an example of an optimization study for a parallel-hole, fan-beam, cone-beam, and multiple-pinhole collimator for different applications. PMID:26233207

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.

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.

Simplifying volumes-of-interest (VOIs) definition in quantitative SPECT: Beyond manual definition of 3D whole-organ VOIs.

PubMed

Vicente, Esther M; Lodge, Martin A; Rowe, Steven P; Wahl, Richard L; Frey, Eric C

2017-05-01

We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate the organ activity concentration in single photon emission computed tomography (SPECT) in cases where the activity in the organ can be assumed to be uniformly distributed on the scale of the voxel size. In particular, we investigated an anatomic region-of-interest (ROI) defined in a single transaxial slice, and a single sphere placed inside the organ boundaries. The evaluation was carried out using Monte Carlo simulations based on patient indium 111 In pentetreotide SPECT and computed tomography (CT) images. We modeled constant activity concentrations in each organ, validating this assumption by comparing the distribution of voxel values inside the organ VOIs of the simulated data with the patient data. We simulated projection data corresponding to 100, 50, and 25% of the clinical count level to study the effects of noise level due to shortened acquisition time. Images were reconstructed using a previously validated quantitative SPECT reconstruction method. The evaluation was performed in terms of the accuracy and precision of the activity concentration estimates. The results demonstrated that the non-uniform image intensity observed in the reconstructed images in the organs with normal uptake was consistent with uniform activity concentration in the organs on the scale of the voxel size; observed non-uniformities in image intensity were due to a combination of partial-volume effects at the boundaries of the organ, artifacts in the reconstructed image due to collimator-detector response compensation, and noise. Using an ROI defined in a single transaxial slice produced similar biases compared to the three-dimensional (3D) whole-organ VOIs, provided that the transaxial slice was near the central plane of the organ and that the pixels from the organ boundaries were not included in the ROI. Although this slice method was sensitive to noise

Radiolabeled bombesin derivatives for preclinical oncological imaging

PubMed Central

de Aguiar Ferreira, Carolina; Fuscaldi, Leonardo Lima; Townsend, Danyelle M.; Rubello, Domenico; de Barros, André Luís Branco

2017-01-01

Despite efforts, cancer is still one of the leading causes of morbidity and mortality worldwide, with approximately 14 million new cases and 8.2 million cancer-related deaths each year, according to the World Health Organization. Among the strategies to reduce cancer progression and improving its management, implementing early detection technologies is crucial. Based on the fact that several types of cancer cells overexpress surface receptors, small molecule ligands, such as peptides, have been developed to allow tumor identification at earlier stages. Allied with imaging techniques such as PET and SPECT, radiolabeled peptides play a pivotal role in nuclear medicine. Bombesin, a peptide of 14 amino acids, is an amphibian homolog to the mammalian gastrin-releasing peptide (GRP), that has been extensively studied as a targeting ligand for diagnosis and therapy of GRP positive tumors, such as breast, pancreas, lungs and prostate cancers. In this context, herein we provide a review of reported bombesin derivatives radiolabeled with a multitude of radioactive isotopes for diagnostic purposes in the preclinical setting. Moreover, since animal models are highly relevant for assessing the potential of clinical translation of this radiopeptides, a brief report of the currently used GRP-positive tumor-bearing animal models is described. PMID:28040598

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

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.

Preclinical Evaluation of RYM1, a Matrix Metalloproteinase-Targeted Tracer for Imaging Aneurysm.

PubMed

Toczek, Jakub; Ye, Yunpeng; Gona, Kiran; Kim, Hye-Yeong; Han, Jinah; Razavian, Mahmoud; Golestani, Reza; Zhang, Jiasheng; Wu, Terence L; Jung, Jae-Joon; Sadeghi, Mehran M

2017-08-01

Matrix metalloproteinases (MMPs) play a key role in abdominal aortic aneurysm (AAA) development. Accordingly, MMP-targeted imaging provides important information regarding vessel wall biology in the course of aneurysm development. Given the small size of the vessel wall and its proximity with blood, molecular imaging of aneurysm optimally requires highly sensitive tracers with rapid blood clearance. To this end, we developed a novel hydrosoluble zwitterionic MMP inhibitor, RYM, on the basis of which a pan-MMP tracer, RYM1, was designed. Here, we describe the development and preclinical evaluation of RYM1 in comparison with RP805, a commonly used pan-MMP tracer in murine models of aneurysm. Methods: The macrocyclic hydroxamate-based pan-MMP inhibitor coupled with 6-hydrazinonicotinamide, RYM1, was synthesized and labeled with 99m Tc. Radiochemical stability of 99m Tc-RYM1 was evaluated by radio-high-performance liquid chromatography analysis. Tracer blood kinetics and biodistribution were compared with 99m Tc-RP805 in C57BL/6J mice ( n = 10). 99m Tc-RYM1 binding to aneurysm and specificity were evaluated by quantitative autoradiography in apolipoprotein E-deficient (apoE -/- ) mice with CaCl 2 -induced carotid aneurysm ( n = 11). Angiotensin II-infused apoE -/- ( n = 16) mice were used for small-animal SPECT/CT imaging. Aortic tissue MMP activity and macrophage marker CD68 expression were assessed by zymography and reverse-transcription polymerase chain reaction. Results: RYM1 showed nanomolar range inhibition constants for several MMPs. 99m Tc-RYM1 was radiochemically stable in mouse blood for 5 h and demonstrated rapid renal clearance and lower blood levels in vivo compared with 99m Tc-RP805. 99m Tc-RYM1 binding to aneurysm and its specificity were shown by autoradiography in carotid aneurysm. Angiotensin II infusion in apoE -/- mice for 4 wk resulted in AAA formation in 36% (4/11) of surviving animals. In vivo 99m Tc-RYM1 small-animal SPECT/CT images showed

Radiolabeled novel mAb 4G1 for immunoSPECT imaging of EGFRvIII expression in preclinical glioblastoma xenografts.

PubMed

Liu, Xujie; Dong, Chengyan; Shi, Jiyun; Ma, Teng; Jin, Zhongxia; Jia, Bing; Liu, Zhaofei; Shen, Li; Wang, Fan

2017-01-24

Epidermal growth factor receptor mutant III (EGFRvIII) is exclusively expressed in tumors, such as glioblastoma, breast cancer and hepatocellular carcinoma, but never in normal organs. Increasing evidence suggests that EGFRvIII has clinical significance in glioblastoma prognosis due to its enhanced tumorigenicity and chemo/radio resistance, thus the development of an imaging approach to early detect EGFRvIII expression with high specificity is urgently needed. To illustrate this point, we developed a novel anti-EGFRvIII monoclonal antibody 4G1 through mouse immunization, cell fusion and hybridoma screening and then confirmed its specificity and affinity by a serial of assays. Following biodistribution and small animal single-photon emission computed tomography (SPECT/CT) imaging of 125I-4G1 in EGFRvIII positive/negative tumor-bearing mice were performed and evaluated to verify the tumor accumulation of this radiotracer. The biodistribution indicated that 125I-4G1 showed prominent tumor accumulation at 24 h post-injection, which reached maximums of 11.20 ± 0.75% ID/g and 13.98 ± 0.57% ID/g in F98npEGFRvIII and U87vIII xenografts, respectively. In contrast, 125I-4G1 had lower tumor accumulation in F98npEGFR and U87MG xenografts. Small animal SPECT/CT imaging revealed that 125I-4G1 had a higher tumor uptake in EGFRvIII-positive tumors than that in EGFRvIII-negative tumors. This study demonstrates that radiolabeled 4G1 can serve as a valid probe for the imaging of EGFRvIII expression, and would be valuable into the clinical translation for the diagnosis, prognosis, guiding therapy, and therapeutic efficacy evaluation of tumors.

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.

Brain SPECT scans in students with specific learning disability: Preliminary results.

PubMed

Karande, S; Deshmukh, N; Rangarajan, V; Agrawal, A; Sholapurwala, R

2018-06-08

Brain single-photon emission computed tomography (SPECT) assesses brain function through measurement of regional cerebral blood flow. This study was conducted to assess whether students with newly diagnosed specific learning disability (SpLD) show any abnormalities in cerebral cortex perfusion. Cross-sectional single-arm pilot study in two tertiary care hospitals. Nine students with SpLD were enrolled. Brain SPECT scan was done twice in each student. For the first or "baseline" scan, the student was first made to sit with eyes open in a quiet, dimly lit room for a period of 30-40 min and then injected intravenously with 20 mCi of 99mTc-ECD. An hour later, "baseline scan" was conducted. After a minimum gap of 4 days, a second or "test scan" was conducted, wherein the student performed an age-appropriate curriculum-based test for a period of 30-40 min to activate the areas in central nervous system related to learning before being injected with 20 mCi of 99mTc-ECD. Cerebral cortex perfusion at rest and after activation in each student was compared qualitatively by visual analysis and quantitatively using NeuroGam TM software. Visual analysis showed reduction in regional blood flow in temporoparietal areas in both "baseline" and "test" scans. However, when normalization was attempted and comparison done by Talairach analysis using NeuroGam software, no statistically significant change in regional perfusion in temporoparietal areas was appreciated. Brain SPECT scan may serve as a robust tool to identify changes in regional brain perfusion in students with SpLD.

Experimental validation of absolute SPECT/CT quantification for response monitoring in breast cancer.

PubMed

Collarino, Angela; Pereira Arias-Bouda, Lenka M; Valdés Olmos, Renato A; van der Tol, Pieternel; Dibbets-Schneider, Petra; de Geus-Oei, Lioe-Fee; van Velden, Floris H P

2018-05-01

Recent developments in iterative image reconstruction enable absolute quantification of SPECT/CT studies by incorporating compensation for collimator-detector response, attenuation, and scatter as well as resolution recovery into the reconstruction process (Evolution; Q.Metrix package; GE Healthcare, Little Chalfont, UK). The aim of this experimental study is to assess its quantitative accuracy for potential clinical 99m Tc-sestamibi (MIBI)-related SPECT/CT application in neoadjuvant chemotherapy response studies in breast cancer. Two phantoms were filled with MIBI and acquired on a SPECT/CT gamma camera (Discovery 670 Pro; GE Healthcare), that is, a water cylinder and a NEMA body phantom containing six spheres that were filled with an activity concentration reflecting clinical MIBI uptake. Subsequently, volumes-of-interest (VOI) of each sphere were drawn (semi)automatically on SPECT using various isocontour methods or manually on CT. Finally, prone MIBI SPECT/CT scans were acquired 5 and 90 min p.i. in a locally advanced breast cancer patient. Activity concentration in the four largest spheres converged after nine iterations of evolution. Depending on the count statistics, the accuracy of the reconstructed activity concentration varied between -4.7 and -0.16% (VOI covering the entire phantom) and from 6.9% to 10% (8.8 cm ⌀ cylinder VOI placed in the center of the phantom). Recovery coefficients of SUV max were 1.89 ± 0.18, 1.76 ± 0.17, 2.00 ± 0.38, 1.89 ± 0.35, and 0.90 ± 0.26 for spheres with 37, 28, 22, 17, and 13 mm ⌀, respectively. Recovery coefficients of SUV mean were 1.07 ± 0.06, 1.03 ± 0.09, 1.17 ± 0.21, 1.10 ± 0.20, and 0.52 ± 0.14 (42% isocontour); 1.10 ± 0.07, 1.02 ± 0.09, 1.13 ± 0.19, 1.06 ± 0.19, and 0.51 ± 0.13 (36% isocontour with local background correction); and 0.96, 1.09, 1.03, 1.03, and 0.29 (CT). Patient study results were concordant with the phantom validation. Absolute SPECT/CT quantification of breast studies using MIBI

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

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.

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.

Brain pertechnetate SPECT in perinatal asphyxia

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

Sfakianakis, G.; Curless, R.; Goldberg, R.

1984-01-01

Single photon emission computed tomography of the brain was performed in 6 patients with perinatal asphyxis aged 8-26 days. A single-head (LFOV) commercial SPECT system (Picker) was used and data were acquired 2-3 hr after an IV injection of 1-2 mCi Tc-99m-pertechnetate (360/sup 0/ rotation, 60 views, 64 x 64 matrix, 50K cts/view). Reconstruction in three planes was performed using MDS software (Hanning medium resolution filter, with or without attenuation correction using Sorenson's technique). For each clinical study, a ring type phantom source was used to identify the level of reconstruction noise in the tomographic planes. Abnormalities were found inmore » all patients studied, 3 central (moderate intensity), 2 peripheral (1 severe, 1 moderate) and 1 diffuse (mild intensity). Despite use of oral perchlorate (50 mg) in one patient the choroid plexus was visible. Since attenuation correction tended to amplify noise, the clinical studies were interpreted both with and without this correction. All 3 patients with central lesions were found abnormal on early (1-4 mo) neurologic follow-up examination, whereas the others were normal. No correlation was found between SPECT and 24 hr blood levels of CPK, ammonia, base excess, or the Apgar scores. Ct scans were reported abnormal (3 diffuse, 1 peripheral, 1 central and 1 questionable). Planar scintigrams obtained immediately after SPECT were normal (2), questionable (2) and abnormal (2). Follow-up SPECT brain scintigrams in two of the patients showed partial resolution. SPECT of the brain appears promising in perinatal asphyxia but long-term correlation with patient development is necessary.« less

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.

Absolute activity quantitation from projections using an analytical approach: comparison with iterative methods in Tc-99m and I-123 brain SPECT

NASA Astrophysics Data System (ADS)

Fakhri, G. El; Kijewski, M. F.; Moore, S. C.

2001-06-01

Estimates of SPECT activity within certain deep brain structures could be useful for clinical tasks such as early prediction of Alzheimer's disease with Tc-99m or Parkinson's disease with I-123; however, such estimates are biased by poor spatial resolution and inaccurate scatter and attenuation corrections. We compared an analytical approach (AA) of more accurate quantitation to a slower iterative approach (IA). Monte Carlo simulated projections of 12 normal and 12 pathologic Tc-99m perfusion studies, as well as 12, normal and 12 pathologic I-123 neurotransmission studies, were generated using a digital brain phantom and corrected for scatter by a multispectral fitting procedure. The AA included attenuation correction by a modified Metz-Fan algorithm and activity estimation by a technique that incorporated Metz filtering to compensate for variable collimator response (VCR), IA-modeled attenuation, and VCR in the projector/backprojector of an ordered subsets-expectation maximization (OSEM) algorithm. Bias and standard deviation over the 12 normal and 12 pathologic patients were calculated with respect to the reference values in the corpus callosum, caudate nucleus, and putamen. The IA and AA yielded similar quantitation results in both Tc-99m and I-123 studies in all brain structures considered in both normal and pathologic patients. The bias with respect to the reference activity distributions was less than 7% for Tc-99m studies, but greater than 30% for I-123 studies, due to partial volume effect in the striata. Our results were validated using I-123 physical acquisitions of an anthropomorphic brain phantom. The IA yielded quantitation accuracy comparable to that obtained with IA, while requiring much less processing time. However, in most conditions, IA yielded lower noise for the same bias than did AA.

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.

[Myokard-Perfusions-SPECT. Myocardial perfusion SPECT - Update S1 guideline].

PubMed

Lindner, Oliver; Bengel, Frank; Burchert, Wolfgang; Dörr, Rolf; Hacker, Marcus; Schäfer, Wolfgang; Schäfers, Michael A; Schmidt, Matthias; Schwaiger, Markus; Vom Dahl, Jürgen; Zimmermann, Rainer

2017-08-14

The S1 guideline for myocardial perfusion SPECT has been published by the Association of the Scientific Medical Societies in Germany (AWMF) and is valid until 2/2022. This paper is a short summary with comments on all chapters and subchapters wich were modified and amended.

Monte Carlo Optimization of Crystal Configuration for Pixelated Molecular SPECT Scanners

NASA Astrophysics Data System (ADS)

Mahani, Hojjat; Raisali, Gholamreza; Kamali-Asl, Alireza; Ay, Mohammad Reza

2017-02-01

Resolution-sensitivity-PDA tradeoff is the most challenging problem in design and optimization of pixelated preclinical SPECT scanners. In this work, we addressed such a challenge from a crystal point-of-view by looking for an optimal pixelated scintillator using GATE Monte Carlo simulation. Various crystal configurations have been investigated and the influence of different pixel sizes, pixel gaps, and three scintillators on tomographic resolution, sensitivity, and PDA of the camera were evaluated. The crystal configuration was then optimized using two objective functions: the weighted-sum and the figure-of-merit methods. The CsI(Na) reveals the highest sensitivity of the order of 43.47 cps/MBq in comparison to the NaI(Tl) and the YAP(Ce), for a 1.5×1.5 mm2 pixel size and 0.1 mm gap. The results show that the spatial resolution, in terms of FWHM, improves from 3.38 to 2.21 mm while the sensitivity simultaneously deteriorates from 42.39 cps/MBq to 27.81 cps/MBq when pixel size varies from 2×2 mm2 to 0.5×0.5 mm2 for a 0.2 mm gap, respectively. The PDA worsens from 0.91 to 0.42 when pixel size decreases from 0.5×0.5 mm2 to 1×1 mm2 for a 0.2 mm gap at 15° incident-angle. The two objective functions agree that the 1.5×1.5 mm2 pixel size and 0.1 mm Epoxy gap CsI(Na) configuration provides the best compromise for small-animal imaging, using the HiReSPECT scanner. Our study highlights that crystal configuration can significantly affect the performance of the camera, and thereby Monte Carlo optimization of pixelated detectors is mandatory in order to achieve an optimal quality tomogram.

Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering

NASA Astrophysics Data System (ADS)

Lienemann, Philipp S.; Metzger, Stéphanie; Kiveliö, Anna-Sofia; Blanc, Alain; Papageorgiou, Panagiota; Astolfo, Alberto; Pinzer, Bernd R.; Cinelli, Paolo; Weber, Franz E.; Schibli, Roger; Béhé, Martin; Ehrbar, Martin

2015-05-01

Over the last decades, great strides were made in the development of novel implants for the treatment of bone defects. The increasing versatility and complexity of these implant designs request for concurrent advances in means to assess in vivo the course of induced bone formation in preclinical models. Since its discovery, micro-computed tomography (micro-CT) has excelled as powerful high-resolution technique for non-invasive assessment of newly formed bone tissue. However, micro-CT fails to provide spatiotemporal information on biological processes ongoing during bone regeneration. Conversely, due to the versatile applicability and cost-effectiveness, single photon emission computed tomography (SPECT) would be an ideal technique for assessing such biological processes with high sensitivity and for nuclear imaging comparably high resolution (<1 mm). Herein, we employ modular designed poly(ethylene glycol)-based hydrogels that release bone morphogenetic protein to guide the healing of critical sized calvarial bone defects. By combined in vivo longitudinal multi-pinhole SPECT and micro-CT evaluations we determine the spatiotemporal course of bone formation and remodeling within this synthetic hydrogel implant. End point evaluations by high resolution micro-CT and histological evaluation confirm the value of this approach to follow and optimize bone-inducing biomaterials.

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

SU-E-CAMPUS-I-05: Internal Dosimetric Calculations for Several Imaging Radiopharmaceuticals in Preclinical Studies and Quantitative Assessment of the Mouse Size Impact On Them. Realistic Monte Carlo Simulations Based On the 4D-MOBY Model

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

Kostou, T; Papadimitroulas, P; Kagadis, GC

2014-06-15

Purpose: Commonly used radiopharmaceuticals were tested to define the most important dosimetric factors in preclinical studies. Dosimetric calculations were applied in two different whole-body mouse models, with varying organ size, so as to determine their impact on absorbed doses and S-values. Organ mass influence was evaluated with computational models and Monte Carlo(MC) simulations. Methods: MC simulations were executed on GATE to determine dose distribution in the 4D digital MOBY mouse phantom. Two mouse models, 28 and 34 g respectively, were constructed based on realistic preclinical exams to calculate the absorbed doses and S-values of five commonly used radionuclides in SPECT/PETmore » studies (18F, 68Ga, 177Lu, 111In and 99mTc).Radionuclide biodistributions were obtained from literature. Realistic statistics (uncertainty lower than 4.5%) were acquired using the standard physical model in Geant4. Comparisons of the dosimetric calculations on the two different phantoms for each radiopharmaceutical are presented. Results: Dose per organ in mGy was calculated for all radiopharmaceuticals. The two models introduced a difference of 0.69% in their brain masses, while the largest differences were observed in the marrow 18.98% and in the thyroid 18.65% masses.Furthermore, S-values of the most important target-organs were calculated for each isotope. Source-organ was selected to be the whole mouse body.Differences on the S-factors were observed in the 6.0–30.0% range. Tables with all the calculations as reference dosimetric data were developed. Conclusion: Accurate dose per organ and the most appropriate S-values are derived for specific preclinical studies. The impact of the mouse model size is rather high (up to 30% for a 17.65% difference in the total mass), and thus accurate definition of the organ mass is a crucial parameter for self-absorbed S values calculation.Our goal is to extent the study for accurate estimations in small animal imaging, whereas it is

The Assay Guidance Manual: Quantitative Biology and Pharmacology in Preclinical Drug Discovery.

PubMed

Coussens, Nathan P; Sittampalam, G Sitta; Guha, Rajarshi; Brimacombe, Kyle; Grossman, Abigail; Chung, Thomas D Y; Weidner, Jeffrey R; Riss, Terry; Trask, O Joseph; Auld, Douglas; Dahlin, Jayme L; Devanaryan, Viswanath; Foley, Timothy L; McGee, James; Kahl, Steven D; Kales, Stephen C; Arkin, Michelle; Baell, Jonathan; Bejcek, Bruce; Gal-Edd, Neely; Glicksman, Marcie; Haas, Joseph V; Iversen, Philip W; Hoeppner, Marilu; Lathrop, Stacy; Sayers, Eric; Liu, Hanguan; Trawick, Bart; McVey, Julie; Lemmon, Vance P; Li, Zhuyin; McManus, Owen; Minor, Lisa; Napper, Andrew; Wildey, Mary Jo; Pacifici, Robert; Chin, William W; Xia, Menghang; Xu, Xin; Lal-Nag, Madhu; Hall, Matthew D; Michael, Sam; Inglese, James; Simeonov, Anton; Austin, Christopher P

2018-06-07

The Assay Guidance Manual (AGM) is an eBook of best-practices for the design, development, and implementation of robust assays for early drug discovery. Initiated by pharmaceutical company scientists, the manual provides guidance for designing a "testing funnel" of assays to identify genuine hits using high-throughput screening (HTS) and advancing them through pre-clinical development. Combined with a workshop/tutorial component, the overall goal of the AGM is to provide a valuable resource for training translational scientists. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Quantification of the spatial distribution of rectally applied surrogates for microbicide and semen in colon with SPECT and magnetic resonance imaging

PubMed Central

Cao, Ying J; Caffo, Brian S; Fuchs, Edward J; Lee, Linda A; Du, Yong; Li, Liye; Bakshi, Rahul P; Macura, Katarzyna; Khan, Wasif A; Wahl, Richard L; Grohskopf, Lisa A; Hendrix, Craig W

2012-01-01

AIMS We sought to describe quantitatively the distribution of rectally administered gels and seminal fluid surrogates using novel concentration–distance parameters that could be repeated over time. These methods are needed to develop rationally rectal microbicides to target and prevent HIV infection. METHODS Eight subjects were dosed rectally with radiolabelled and gadolinium-labelled gels to simulate microbicide gel and seminal fluid. Rectal doses were given with and without simulated receptive anal intercourse. Twenty-four hour distribution was assessed with indirect single photon emission computed tomography (SPECT)/computed tomography (CT) and magnetic resonance imaging (MRI), and direct assessment via sigmoidoscopic brushes. Concentration–distance curves were generated using an algorithm for fitting SPECT data in three dimensions. Three novel concentration–distance parameters were defined to describe quantitatively the distribution of radiolabels: maximal distance (Dmax), distance at maximal concentration (DCmax) and mean residence distance (Dave). RESULTS The SPECT/CT distribution of microbicide and semen surrogates was similar. Between 1 h and 24 h post dose, the surrogates migrated retrograde in all three parameters (relative to coccygeal level; geometric mean [95% confidence interval]): maximal distance (Dmax), 10 cm (8.6–12) to 18 cm (13–26), distance at maximal concentration (DCmax), 3.8 cm (2.7–5.3) to 4.2 cm (2.8–6.3) and mean residence distance (Dave), 4.3 cm (3.5–5.1) to 7.6 cm (5.3–11). Sigmoidoscopy and MRI correlated only roughly with SPECT/CT. CONCLUSIONS Rectal microbicide surrogates migrated retrograde during the 24 h following dosing. Spatial kinetic parameters estimated using three dimensional curve fitting of distribution data should prove useful for evaluating rectal formulations of drugs for HIV prevention and other indications. PMID:22404308

Quantification of the spatial distribution of rectally applied surrogates for microbicide and semen in colon with SPECT and magnetic resonance imaging.

PubMed

Cao, Ying J; Caffo, Brian S; Fuchs, Edward J; Lee, Linda A; Du, Yong; Li, Liye; Bakshi, Rahul P; Macura, Katarzyna; Khan, Wasif A; Wahl, Richard L; Grohskopf, Lisa A; Hendrix, Craig W

2012-12-01

We sought to describe quantitatively the distribution of rectally administered gels and seminal fluid surrogates using novel concentration-distance parameters that could be repeated over time. These methods are needed to develop rationally rectal microbicides to target and prevent HIV infection. Eight subjects were dosed rectally with radiolabelled and gadolinium-labelled gels to simulate microbicide gel and seminal fluid. Rectal doses were given with and without simulated receptive anal intercourse. Twenty-four hour distribution was assessed with indirect single photon emission computed tomography (SPECT)/computed tomography (CT) and magnetic resonance imaging (MRI), and direct assessment via sigmoidoscopic brushes. Concentration-distance curves were generated using an algorithm for fitting SPECT data in three dimensions. Three novel concentration-distance parameters were defined to describe quantitatively the distribution of radiolabels: maximal distance (D(max) ), distance at maximal concentration (D(Cmax) ) and mean residence distance (D(ave) ). The SPECT/CT distribution of microbicide and semen surrogates was similar. Between 1 h and 24 h post dose, the surrogates migrated retrograde in all three parameters (relative to coccygeal level; geometric mean [95% confidence interval]): maximal distance (D(max) ), 10 cm (8.6-12) to 18 cm (13-26), distance at maximal concentration (D(Cmax) ), 3.8 cm (2.7-5.3) to 4.2 cm (2.8-6.3) and mean residence distance (D(ave) ), 4.3 cm (3.5-5.1) to 7.6 cm (5.3-11). Sigmoidoscopy and MRI correlated only roughly with SPECT/CT. Rectal microbicide surrogates migrated retrograde during the 24 h following dosing. Spatial kinetic parameters estimated using three dimensional curve fitting of distribution data should prove useful for evaluating rectal formulations of drugs for HIV prevention and other indications. © 2012 The Authors. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

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.

Noise suppressed partial volume correction for cardiac SPECT/CT

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

Chan, Chung; Liu, Chi, E-mail: chi.liu@yale.edu

Purpose: Partial volume correction (PVC) methods typically improve quantification at the expense of increased image noise and reduced reproducibility. In this study, the authors developed a novel voxel-based PVC method that incorporates anatomical knowledge to improve quantification while suppressing noise for cardiac SPECT/CT imaging. Methods: In the proposed method, the SPECT images were first reconstructed using anatomical-based maximum a posteriori (AMAP) with Bowsher’s prior to penalize noise while preserving boundaries. A sequential voxel-by-voxel PVC approach (Yang’s method) was then applied on the AMAP reconstruction using a template response. This template response was obtained by forward projecting a template derived frommore » a contrast-enhanced CT image, and then reconstructed using AMAP to model the partial volume effects (PVEs) introduced by both the system resolution and the smoothing applied during reconstruction. To evaluate the proposed noise suppressed PVC (NS-PVC), the authors first simulated two types of cardiac SPECT studies: a {sup 99m}Tc-tetrofosmin myocardial perfusion scan and a {sup 99m}Tc-labeled red blood cell (RBC) scan on a dedicated cardiac multiple pinhole SPECT/CT at both high and low count levels. The authors then applied the proposed method on a canine equilibrium blood pool study following injection with {sup 99m}Tc-RBCs at different count levels by rebinning the list-mode data into shorter acquisitions. The proposed method was compared to MLEM reconstruction without PVC, two conventional PVC methods, including Yang’s method and multitarget correction (MTC) applied on the MLEM reconstruction, and AMAP reconstruction without PVC. Results: The results showed that the Yang’s method improved quantification, however, yielded increased noise and reduced reproducibility in the regions with higher activity. MTC corrected for PVE on high count data with amplified noise, although yielded the worst performance among all the

Preclinical restorative training.

PubMed

Ferguson, Michael B; Sobel, Morton; Niederman, Richard

2002-10-01

In conjunction with its problem-based learning curriculum, Harvard School of Dental Medicine (HSDM) developed a shortened preclinical restorative training curriculum. This study compared our curriculum with those in other dental schools and examined student reaction to it. Twenty-nine U.S. dental schools responded to a survey regarding the length of their preclinical course in Operative Dentistry. Nationally, preclinical courses ranged from 179 hours to 280 hours (mean +/- SEM = 193 +/- 9 hours; n = 29). In marked contrast, the new seventy-five-hour preclinical curriculum at Harvard was the lowest of any school, and significantly lower than the U.S. average (p < 0.01). In Harvard's previous curriculum, students spent 232 curriculum hours. Reactions of Harvard students to this compact preclinical curriculum were surveyed using a three-topic, three-category survey instrument. Results indicated that, prior to beginning clinical patient care, approximately 80 percent of students felt that the course was too short and 20 percent just right. Conversely, and retrospectively, after completing their dental school training, only 35 percent felt it was too short, and 65 percent felt it was just right. Retrospectively, in terms of clinical preparedness, 55 percent felt adequately prepared and 35 percent felt well prepared to treat their patients. No significant change was noted between Part II National Board scores following the change to the reduced curricula time. The average National Board Part II scores prior to initiating the new curriculum was 86.3, and afterwards, it was 86.2. Further, for the North East Regional Board, HSDM students in the past four years demonstrated a 98 percent overall success rate with 100 percent primary pass in the operative dentistry part of the examination. These results suggest that an abbreviated preclinical training is not only possible, but may make time available for training opportunities in other areas, such as aesthetic dental

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

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.

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.

Hemimegalencephaly: Clinical, EEG, neuroimaging, and IMP-SPECT correlation

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

Konkol, R.J.; Maister, B.H.; Wells, R.G.

1990-11-01

Iofetamine-single photon emission computed tomography (IMP-SPECT) was performed on 2 girls (5 1/2 and 6 years of age) with histories of intractable seizures, developmental delay, and unilateral hemiparesis secondary to hemimegalencephaly. Electroencephalography (EEG) revealed frequent focal discharges in 1 patient, while a nearly continuous burst suppression pattern over the malformed hemisphere was recorded in the other. IMP-SPECT demonstrated a good correlation with neuroimaging studies. In spite of the different EEG patterns, which had been proposed to predict contrasting clinical outcomes, both IMP-SPECT scans disclosed a similar decrease in tracer uptake in the malformed hemisphere. These results are consistent with themore » pattern of decreased tracer uptake found in other interictal studies of focal seizures without cerebral malformations. In view of recent recommendations for hemispherectomy in these patients, we suggest that the IMP-SPECT scan be used to compliment EEG as a method to define the extent of abnormality which may be more relevant to long-term prognosis than EEG alone.« less

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.

SPECT/CT tracer uptake is influenced by tunnel orientation and position of the femoral and tibial ACL graft insertion site.

PubMed

Hirschmann, Michael T; Mathis, Dominic; Rasch, Helmut; Amsler, Felix; Friederich, Niklaus F; Arnold, Markus P

2013-02-01

SPECT/CT is a hybrid imaging modality, which combines a 3D scintigraphy (SPECT) and a conventional computerised tomography (CT). SPECT/CT allows accurate anatomical localisation of metabolic tracer activity. It allows the correlation of surgical factors such as tunnel position and orientation with mechanical alignment, clinical outcome and biological factors. The purpose of this study was to investigate whether the SPECT/CT tracer uptake (intensity and distribution) correlates with the stability and laxity of the knee joint and the position and orientation of the tibial and femoral tunnels in patients after anterior cruciate ligament (ACL) reconstruction. A consecutive series of knees (n=66), with symptoms of pain and/or instability after ACL reconstruction were prospectively evaluated using clinical examination and 99mTc-HDP-SPECT/CT. Clinical laxity testing was performed using the Rolimeter (Ormed, Freiburg, Germany) including Lachman testing (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), anterior drawer test (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), pivot shift test (positive versus negative) and patient-based subjective instability (yes versus no). For analysis of SPECT/CT tracer uptake a previously validated SPECT/CT localisation scheme consisting of 17 tibial, nine femoral and four patellar regions on standardised axial, coronal, and sagittal slices was used. The tracer activity on SPECT/CT was localised and recorded using a 3D volumetric and quantitative analysis software. Mean, standard deviation, minimum and maximum of grading for each area of the localisation scheme were recorded. The position and orientation of the tibial and femoral tunnel was assessed using a previously published method on 3D-CT. Correlation of instability, pivot shift as well as clinical laxity testing with 99mTc-HDP-SPECT/CT tracer uptake intensity and distribution showed no significant correlation. 99mTc-HDP-SPECT/CT tracer uptake correlated significantly with the position and orientation of the ACL

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

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

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

Magnetoencephalography and ictal SPECT in patients with failed epilepsy surgery.

PubMed

El Tahry, Riёm; Wang, Z Irene; Thandar, Aung; Podkorytova, Irina; Krishnan, Balu; Tousseyn, Simon; Guiyun, Wu; Burgess, Richard C; Alexopoulos, Andreas V

2018-06-06

Selected patients with intractable focal epilepsy who have failed a previous epilepsy surgery can become seizure-free with reoperation. Preoperative evaluation is exceedingly challenging in this cohort. We aim to investigate the diagnostic value of two noninvasive approaches, magnetoencephalography (MEG) and ictal single-photon emission computed tomography (SPECT), in patients with failed epilepsy surgery. We retrospectively included a consecutive cohort of patients who failed prior resective epilepsy surgery, underwent re-evaluation including MEG and ictal SPECT, and had another surgery after the re-evaluation. The relationship between resection and localization from each test was determined, and their association with seizure outcomes was analyzed. A total of 46 patients were included; 21 (46%) were seizure-free at 1-year followup after reoperation. Twenty-seven (58%) had a positive MEG and 31 (67%) had a positive ictal SPECT. The resection of MEG foci was significantly associated with seizure-free outcome (p = 0.002). Overlap of ictal SPECT hyperperfusion zones with resection was significantly associated with seizure-free outcome in the subgroup of patients with injection time ≤20 seconds(p = 0.03), but did not show significant association in the overall cohort (p = 0.46) although all injections were ictal. Patients whose MEG and ictal SPECT were concordant on a sublobar level had a significantly higher chance of seizure freedom (p = 0.05). MEG alone achieved successful localization in patients with failed epilepsy surgery with a statistical significance. Only ictal SPECT with early injection (≤20 seconds) had good localization value. Sublobar concordance between both tests was significantly associated with seizure freedom. SPECT can provide essential information in MEG-negative cases and vice versa. Our results emphasize the importance of considering a multimodal presurgical evaluation including MEG and SPECT in all patients with a

Automated Quantitative Nuclear Cardiology Methods

PubMed Central

Motwani, Manish; Berman, Daniel S.; Germano, Guido; Slomka, Piotr J.

2016-01-01

Quantitative analysis of SPECT and PET has become a major part of nuclear cardiology practice. Current software tools can automatically segment the left ventricle, quantify function, establish myocardial perfusion maps and estimate global and local measures of stress/rest perfusion – all with minimal user input. State-of-the-art automated techniques have been shown to offer high diagnostic accuracy for detecting coronary artery disease, as well as predict prognostic outcomes. This chapter briefly reviews these techniques, highlights several challenges and discusses the latest developments. PMID:26590779

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

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.

Assessing agreement between preclinical magnetic resonance imaging and histology: An evaluation of their image qualities and quantitative results

PubMed Central

Elschner, Cindy; Korn, Paula; Hauptstock, Maria; Schulz, Matthias C.; Range, Ursula; Jünger, Diana; Scheler, Ulrich

2017-01-01

One consequence of demographic change is the increasing demand for biocompatible materials for use in implants and prostheses. This is accompanied by a growing number of experimental animals because the interactions between new biomaterials and its host tissue have to be investigated. To evaluate novel materials and engineered tissues the use of non-destructive imaging modalities have been identified as a strategic priority. This provides the opportunity for studying interactions repeatedly with individual animals, along with the advantages of reduced biological variability and decreased number of laboratory animals. However, histological techniques are still the golden standard in preclinical biomaterial research. The present article demonstrates a detailed method comparison between histology and magnetic resonance imaging. This includes the presentation of their image qualities as well as the detailed statistical analysis for assessing agreement between quantitative measures. Exemplarily, the bony ingrowth of tissue engineered bone substitutes for treatment of a cleft-like maxillary bone defect has been evaluated. By using a graphical concordance analysis the mean difference between MRI results and histomorphometrical measures has been examined. The analysis revealed a slightly but significant bias in the case of the bone volume (biasHisto−MRI:Bone volume=2.40 %, p<0.005) and a clearly significant deviation for the remaining defect width (biasHisto−MRI:Defect width=−6.73 %, p≪0.005). But the study although showed a considerable effect of the analyzed section position to the quantitative result. It could be proven, that the bias of the data sets was less originated due to the imaging modalities, but mainly on the evaluation of different slice positions. The article demonstrated that method comparisons not always need the use of an independent animal study, additionally. PMID:28666026

Improved quantification for local regions of interest in preclinical PET imaging

NASA Astrophysics Data System (ADS)

Cal-González, J.; Moore, S. C.; Park, M.-A.; Herraiz, J. L.; Vaquero, J. J.; Desco, M.; Udias, J. M.

2015-09-01

In Positron Emission Tomography, there are several causes of quantitative inaccuracy, such as partial volume or spillover effects. The impact of these effects is greater when using radionuclides that have a large positron range, e.g. 68Ga and 124I, which have been increasingly used in the clinic. We have implemented and evaluated a local projection algorithm (LPA), originally evaluated for SPECT, to compensate for both partial-volume and spillover effects in PET. This method is based on the use of a high-resolution CT or MR image, co-registered with a PET image, which permits a high-resolution segmentation of a few tissues within a volume of interest (VOI) centered on a region within which tissue-activity values need to be estimated. The additional boundary information is used to obtain improved activity estimates for each tissue within the VOI, by solving a simple inversion problem. We implemented this algorithm for the preclinical Argus PET/CT scanner and assessed its performance using the radionuclides 18F, 68Ga and 124I. We also evaluated and compared the results obtained when it was applied during the iterative reconstruction, as well as after the reconstruction as a postprocessing procedure. In addition, we studied how LPA can help to reduce the ‘spillover contamination’, which causes inaccurate quantification of lesions in the immediate neighborhood of large, ‘hot’ sources. Quantification was significantly improved by using LPA, which provided more accurate ratios of lesion-to-background activity concentration for hot and cold regions. For 18F, the contrast was improved from 3.0 to 4.0 in hot lesions (when the true ratio was 4.0) and from 0.16 to 0.06 in cold lesions (true ratio  =  0.0), when using the LPA postprocessing. Furthermore, activity values estimated within the VOI using LPA during reconstruction were slightly more accurate than those obtained by post-processing, while also visually improving the image contrast and uniformity

Improved quantification for local regions of interest in preclinical PET imaging

PubMed Central

Cal-González, J.; Moore, S. C.; Park, M.-A.; Herraiz, J. L.; Vaquero, J. J.; Desco, M.; Udias, J. M.

2015-01-01

In Positron Emission Tomography, there are several causes of quantitative inaccuracy, such as partial volume or spillover effects. The impact of these effects is greater when using radionuclides that have a large positron range, e.g., 68Ga and 124I, which have been increasingly used in the clinic. We have implemented and evaluated a local projection algorithm (LPA), originally evaluated for SPECT, to compensate for both partial-volume and spillover effects in PET. This method is based on the use of a high-resolution CT or MR image, co-registered with a PET image, which permits a high-resolution segmentation of a few tissues within a volume of interest (VOI) centered on a region within which tissue-activity values need to be estimated. The additional boundary information is used to obtain improved activity estimates for each tissue within the VOI, by solving a simple inversion problem. We implemented this algorithm for the preclinical Argus PET/CT scanner and assessed its performance using the radionuclides 18F, 68Ga and 124I. We also evaluated and compared the results obtained when it was applied during the iterative reconstruction, as well as after the reconstruction as a postprocessing procedure. In addition, we studied how LPA can help to reduce the “spillover contamination”, which causes inaccurate quantification of lesions in the immediate neighborhood of large, “hot” sources. Quantification was significantly improved by using LPA, which provided more accurate ratios of lesion-to-background activity concentration for hot and cold regions. For 18F, the contrast was improved from 3.0 to 4.0 in hot lesions (when the true ratio was 4.0) and from 0.16 to 0.06 in cold lesions (true ratio = 0.0), when using the LPA postprocessing. Furthermore, activity values estimated within the VOI using LPA during reconstruction were slightly more accurate than those obtained by post-processing, while also visually improving the image contrast and uniformity within the VOI

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 Perfusion Imaging Demonstrates Improvement of Traumatic Brain Injury With Transcranial Near-infrared Laser Phototherapy.

PubMed

Henderson, Theodore A; Morries, Larry D

2015-01-01

Traumatic brain injury (TBI) is a growing health concern affecting civilians and military personnel. Near-infrared (NIR) light has shown benefits in animal models and human trials for stroke and in animal models for TBI. Diodes emitting low-level NIR often have lacked therapeutic efficacy, perhaps failing to deliver sufficient radiant energy to the necessary depth. In this case report, a patient with moderate TBI documented in anatomical magnetic resonance imaging (MRI) and perfusion single-photon emission computed tomography (SPECT) received 20 NIR treatments in the course of 2 mo using a high-power NIR laser. Symptoms were monitored by clinical examination and a novel patient diary system specifically designed for this patient population. Clinical application of these levels of infrared energy for this patient with TBI yielded highly favorable outcomes with decreased depression, anxiety, headache, and insomnia, whereas cognition and quality of life improved. Neurological function appeared to improve based on changes in the SPECT by quantitative analysis. NIR in the power range of 10-15 W at 810 and 980 nm can safely and effectively treat chronic symptoms of TBI.

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

Analytically based photon scatter modeling for a multipinhole cardiac SPECT camera.

PubMed

Pourmoghaddas, Amir; Wells, R Glenn

2016-11-01

projections (120 ± 6 keV ) were also extracted from the acquired list-mode SPECT data. Either APD or DEW scatter projections were subtracted from corresponding 140 keV measured projections and then reconstructed with AC (APD-SC and DEW-SC). Quantitative accuracy of the activity measured in the heart for the APD-SC and DEW-SC images was assessed against dose calibrator measurements. The difference between modeled and acquired projections was measured as the root-mean-squared-error (RMSE). APD-modeled projections for a clinical cardiac study were also evaluated. APD-modeled projections showed good agreement with SPECT measurements and had reduced noise compared to DEW scatter estimates. APD-SC reduced mean error in activity measurement compared to DEW-SC in images and the reduction was statistically significant where the scatter fraction (SF) was large (mean SF = 28.5%, T-test p = 0.007). APD-SC reduced measurement uncertainties as well; however, the difference was not found to be statistically significant (F-test p > 0.5). RMSE comparisons showed that elevated levels of scatter did not significantly contribute to a change in RMSE (p > 0.2). Model-based APD scatter estimation is feasible for dedicated cardiac SPECT scanners with pinhole collimators. APD-SC images performed better than DEW-SC images and improved the accuracy of activity measurement in high-scatter scenarios.

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-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

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

Pre-clinical characterization of tissue engineering constructs for bone and cartilage regeneration.

PubMed

Trachtenberg, Jordan E; Vo, Tiffany N; Mikos, Antonios G

2015-03-01

Pre-clinical animal models play a crucial role in the translation of biomedical technologies from the bench top to the bedside. However, there is a need for improved techniques to evaluate implanted biomaterials within the host, including consideration of the care and ethics associated with animal studies, as well as the evaluation of host tissue repair in a clinically relevant manner. This review discusses non-invasive, quantitative, and real-time techniques for evaluating host-materials interactions, quality and rate of neotissue formation, and functional outcomes of implanted biomaterials for bone and cartilage tissue engineering. Specifically, a comparison will be presented for pre-clinical animal models, histological scoring systems, and non-invasive imaging modalities. Additionally, novel technologies to track delivered cells and growth factors will be discussed, including methods to directly correlate their release with tissue growth.

Pre-clinical characterization of tissue engineering constructs for bone and cartilage regeneration

PubMed Central

Trachtenberg, Jordan E.; Vo, Tiffany N.; Mikos, Antonios G.

2014-01-01

Pre-clinical animal models play a crucial role in the translation of biomedical technologies from the bench top to the bedside. However, there is a need for improved techniques to evaluate implanted biomaterials within the host, including consideration of the care and ethics associated with animal studies, as well as the evaluation of host tissue repair in a clinically relevant manner. This review discusses non-invasive, quantitative, and real-time techniques for evaluating host-materials interactions, quality and rate of neotissue formation, and functional outcomes of implanted biomaterials for bone and cartilage tissue engineering. Specifically, a comparison will be presented for pre-clinical animal models, histological scoring systems, and non-invasive imaging modalities. Additionally, novel technologies to track delivered cells and growth factors will be discussed, including methods to directly correlate their release with tissue growth. PMID:25319726

A quantitative analysis of statistical power identifies obesity endpoints for improved in vivo preclinical study design

PubMed Central

Selimkhanov, Jangir; Thompson, W. Clayton; Guo, Juen; Hall, Kevin D.; Musante, Cynthia J.

2017-01-01

The design of well-powered in vivo preclinical studies is a key element in building knowledge of disease physiology for the purpose of identifying and effectively testing potential anti-obesity drug targets. However, as a result of the complexity of the obese phenotype, there is limited understanding of the variability within and between study animals of macroscopic endpoints such as food intake and body composition. This, combined with limitations inherent in the measurement of certain endpoints, presents challenges to study design that can have significant consequences for an anti-obesity program. Here, we analyze a large, longitudinal study of mouse food intake and body composition during diet perturbation to quantify the variability and interaction of key metabolic endpoints. To demonstrate how conclusions can change as a function of study size, we show that a simulated pre-clinical study properly powered for one endpoint may lead to false conclusions based on secondary endpoints. We then propose guidelines for endpoint selection and study size estimation under different conditions to facilitate proper power calculation for a more successful in vivo study design. PMID:28392555

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.

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

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.

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

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

Usefulness of the convexity apparent hyperperfusion sign in 123I-iodoamphetamine brain perfusion SPECT for the diagnosis of idiopathic normal pressure hydrocephalus.

PubMed

Ohmichi, Takuma; Kondo, Masaki; Itsukage, Masahiro; Koizumi, Hidetaka; Matsushima, Shigenori; Kuriyama, Nagato; Ishii, Kazunari; Mori, Etsuro; Yamada, Kei; Mizuno, Toshiki; Tokuda, Takahiko

2018-03-16

OBJECTIVE The gold standard for the diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is the CSF removal test. For elderly patients, however, a less invasive diagnostic method is required. On MRI, high-convexity tightness was reported to be an important finding for the diagnosis of iNPH. On SPECT, patients with iNPH often show hyperperfusion of the high-convexity area. The authors tested 2 hypotheses regarding the SPECT finding: 1) it is relative hyperperfusion reflecting the increased gray matter density of the convexity, and 2) it is useful for the diagnosis of iNPH. The authors termed the SPECT finding the convexity apparent hyperperfusion (CAPPAH) sign. METHODS Two clinical studies were conducted. In study 1, SPECT was performed for 20 patients suspected of having iNPH, and regional cerebral blood flow (rCBF) of the high-convexity area was examined using quantitative analysis. Clinical differences between patients with the CAPPAH sign (CAP) and those without it (NCAP) were also compared. In study 2, the CAPPAH sign was retrospectively assessed in 30 patients with iNPH and 19 healthy controls using SPECT images and 3D stereotactic surface projection. RESULTS In study 1, rCBF of the high-convexity area of the CAP group was calculated as 35.2-43.7 ml/min/100 g, which is not higher than normal values of rCBF determined by SPECT. The NCAP group showed lower cognitive function and weaker responses to the removal of CSF than the CAP group. In study 2, the CAPPAH sign was positive only in patients with iNPH (24/30) and not in controls (sensitivity 80%, specificity 100%). The coincidence rate between tight high convexity on MRI and the CAPPAH sign was very high (28/30). CONCLUSIONS Patients with iNPH showed hyperperfusion of the high-convexity area on SPECT; however, the presence of the CAPPAH sign did not indicate real hyperperfusion of rCBF in the high-convexity area. The authors speculated that patients with iNPH without the CAPPAH sign, despite showing

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.

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

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

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.

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

SPECT myocardial perfusion imaging as an adjunct to coronary calcium score for the detection of hemodynamically significant coronary artery stenosis

PubMed Central

2012-01-01

Background Coronary artery calcifications (CAC) are markers of coronary atherosclerosis, but do not correlate well with stenosis severity. This study intended to evaluate clinical situations where a combined approach of coronary calcium scoring (CS) and nuclear stress test (SPECT-MPI) is useful for the detection of relevant CAD. Methods Patients with clinical indication for invasive coronary angiography (ICA) were included into our study during 08/2005-09/2008. At first all patients underwent CS procedure as part of the study protocol performed by either using a multidetector computed tomography (CT) scanner or a dual-source CT imager. CAC were automatically defined by dedicated software and the Agatston score was semi-automatically calculated. A stress-rest SPECT-MPI study was performed afterwards and scintigraphic images were evaluated quantitatively. Then all patients underwent ICA. Thereby significant CAD was defined as luminal stenosis ≥75% in quantitative coronary analysis (QCA) in ≥1 epicardial vessel. To compare data lacking Gaussian distribution an unpaired Wilcoxon-Test (Mann–Whitney) was used. Otherwise a Students t-test for unpaired samples was applied. Calculations were considered to be significant at a p-value of <0.05. Results We consecutively included 351 symptomatic patients (mean age: 61.2±12.3 years; range: 18–94 years; male: n=240) with a mean Agatston score of 258.5±512.2 (range: 0–4214). ICA verified exclusion of significant CAD in 66/67 (98.5%) patients without CAC. CAC was detected in remaining 284 patients. In 132/284 patients (46.5%) with CS>0 significant CAD was confirmed by ICA, and excluded in 152/284 (53.5%) patients. Sensitivity for CAD detection by CS alone was calculated as 99.2%, specificity was 30.3%, and negative predictive value was 98.5%. An additional SPECT in patients with CS>0 increased specificity to 80.9% while reducing sensitivity to 87.9%. Diagnostic accuracy was 84.2%. Conclusions In patients without CS=0

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.

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

Implementation of compressive sensing for preclinical cine-MRI

NASA Astrophysics Data System (ADS)

Tan, Elliot; Yang, Ming; Ma, Lixin; Zheng, Yahong Rosa

2014-03-01

This paper presents a practical implementation of Compressive Sensing (CS) for a preclinical MRI machine to acquire randomly undersampled k-space data in cardiac function imaging applications. First, random undersampling masks were generated based on Gaussian, Cauchy, wrapped Cauchy and von Mises probability distribution functions by the inverse transform method. The best masks for undersampling ratios of 0.3, 0.4 and 0.5 were chosen for animal experimentation, and were programmed into a Bruker Avance III BioSpec 7.0T MRI system through method programming in ParaVision. Three undersampled mouse heart datasets were obtained using a fast low angle shot (FLASH) sequence, along with a control undersampled phantom dataset. ECG and respiratory gating was used to obtain high quality images. After CS reconstructions were applied to all acquired data, resulting images were quantitatively analyzed using the performance metrics of reconstruction error and Structural Similarity Index (SSIM). The comparative analysis indicated that CS reconstructed images from MRI machine undersampled data were indeed comparable to CS reconstructed images from retrospective undersampled data, and that CS techniques are practical in a preclinical setting. The implementation achieved 2 to 4 times acceleration for image acquisition and satisfactory quality of image reconstruction.

Effects of Piecewise Spatial Smoothing in 4-D SPECT Reconstruction

NASA Astrophysics Data System (ADS)

Qi, Wenyuan; Yang, Yongyi; King, Michael A.

2014-02-01

In nuclear medicine, cardiac gated SPECT images are known to suffer from significantly increased noise owing to limited data counts. Consequently, spatial (and temporal) smoothing has been indispensable for suppressing the noise artifacts in SPECT reconstruction. However, recently we demonstrated that the benefit of spatial processing in motion-compensated reconstruction of gated SPECT (aka 4-D) could be outweighed by its adverse effects on the myocardium, which included degraded wall motion and perfusion defect detectability. In this work, we investigate whether we can alleviate these adverse effects by exploiting an alternative spatial smoothing prior in 4-D based on image total variation (TV). TV based prior is known to induce piecewise smoothing which can preserve edge features (such as boundaries of the heart wall) in reconstruction. However, it is not clear whether such a property would necessarily be beneficial for improving the accuracy of the myocardium in 4-D reconstruction. In particular, it is unknown whether it would adversely affect the detectability of perfusion defects that are small in size or low in contrast. In our evaluation study, we first use Monte Carlo simulated imaging with 4-D NURBS-based cardiac-torso (NCAT) phantom wherein the ground truth is known for quantitative comparison. We evaluated the accuracy of the reconstructed myocardium using a number of metrics, including regional and overall accuracy of the myocardium, accuracy of the phase activity curve (PAC) of the LV wall for wall motion, uniformity and spatial resolution of the LV wall, and detectability of perfusion defects using a channelized Hotelling observer (CHO). For lesion detection, we simulated perfusion defects with different sizes and contrast levels with the focus being on perfusion defects that are subtle. As a preliminary demonstration, we also tested on three sets of clinical acquisitions. From the quantitative results, it was demonstrated that TV smoothing could

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

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

Multipinhole SPECT helical scan parameters and imaging volume

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

Yao, Rutao, E-mail: rutaoyao@buffalo.edu; Deng, Xiao; Wei, Qingyang

Purpose: The authors developed SPECT imaging capability on an animal PET scanner using a multiple-pinhole collimator and step-and-shoot helical data acquisition protocols. The objective of this work was to determine the preferred helical scan parameters, i.e., the angular and axial step sizes, and the imaging volume, that provide optimal imaging performance. Methods: The authors studied nine helical scan protocols formed by permuting three rotational and three axial step sizes. These step sizes were chosen around the reference values analytically calculated from the estimated spatial resolution of the SPECT system and the Nyquist sampling theorem. The nine helical protocols were evaluatedmore » by two figures-of-merit: the sampling completeness percentage (SCP) and the root-mean-square (RMS) resolution. SCP was an analytically calculated numerical index based on projection sampling. RMS resolution was derived from the reconstructed images of a sphere-grid phantom. Results: The RMS resolution results show that (1) the start and end pinhole planes of the helical scheme determine the axial extent of the effective field of view (EFOV), and (2) the diameter of the transverse EFOV is adequately calculated from the geometry of the pinhole opening, since the peripheral region beyond EFOV would introduce projection multiplexing and consequent effects. The RMS resolution results of the nine helical scan schemes show optimal resolution is achieved when the axial step size is the half, and the angular step size is about twice the corresponding values derived from the Nyquist theorem. The SCP results agree in general with that of RMS resolution but are less critical in assessing the effects of helical parameters and EFOV. Conclusions: The authors quantitatively validated the effective FOV of multiple pinhole helical scan protocols and proposed a simple method to calculate optimal helical scan parameters.« less

The impact of 3D volume of interest definition on accuracy and precision of activity estimation in quantitative SPECT and planar processing methods

NASA Astrophysics Data System (ADS)

He, Bin; Frey, Eric C.

2010-06-01

Accurate and precise estimation of organ activities is essential for treatment planning in targeted radionuclide therapy. We have previously evaluated the impact of processing methodology, statistical noise and variability in activity distribution and anatomy on the accuracy and precision of organ activity estimates obtained with quantitative SPECT (QSPECT) and planar (QPlanar) processing. Another important factor impacting the accuracy and precision of organ activity estimates is accuracy of and variability in the definition of organ regions of interest (ROI) or volumes of interest (VOI). The goal of this work was thus to systematically study the effects of VOI definition on the reliability of activity estimates. To this end, we performed Monte Carlo simulation studies using randomly perturbed and shifted VOIs to assess the impact on organ activity estimates. The 3D NCAT phantom was used with activities that modeled clinically observed 111In ibritumomab tiuxetan distributions. In order to study the errors resulting from misdefinitions due to manual segmentation errors, VOIs of the liver and left kidney were first manually defined. Each control point was then randomly perturbed to one of the nearest or next-nearest voxels in three ways: with no, inward or outward directional bias, resulting in random perturbation, erosion or dilation, respectively, of the VOIs. In order to study the errors resulting from the misregistration of VOIs, as would happen, e.g. in the case where the VOIs were defined using a misregistered anatomical image, the reconstructed SPECT images or projections were shifted by amounts ranging from -1 to 1 voxels in increments of with 0.1 voxels in both the transaxial and axial directions. The activity estimates from the shifted reconstructions or projections were compared to those from the originals, and average errors were computed for the QSPECT and QPlanar methods, respectively. For misregistration, errors in organ activity estimations were

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.

Mitigating risk in academic preclinical drug discovery.

PubMed

Dahlin, Jayme L; Inglese, James; Walters, Michael A

2015-04-01

The number of academic drug discovery centres has grown considerably in recent years, providing new opportunities to couple the curiosity-driven research culture in academia with rigorous preclinical drug discovery practices used in industry. To fully realize the potential of these opportunities, it is important that academic researchers understand the risks inherent in preclinical drug discovery, and that translational research programmes are effectively organized and supported at an institutional level. In this article, we discuss strategies to mitigate risks in several key aspects of preclinical drug discovery at academic drug discovery centres, including organization, target selection, assay design, medicinal chemistry and preclinical pharmacology.

Preclinical Alzheimer's Disease: Implications for Refinement of the Concept.

PubMed

Vos, Stephanie J B; Visser, Pieter Jelle

2018-05-23

Increasing interest in clinical trials and clinical research settings to identify Alzheimer's disease (AD) in the earliest stages of the disease has led to the concept of preclinical AD. Individuals with preclinical AD have AD pathology without clinical symptoms yet. Accumulating evidence has shown that biomarkers can identify preclinical AD and that preclinical AD is associated with a poor clinical outcome. Little is known yet about the role of vascular and lifestyle risk factors in the development of preclinical AD. In order to better understand preclinical AD pathology and clinical progression rates, there is a need to refine the concept of preclinical AD. This will be of great value for advancements in future research, clinical trials, and eventually clinical practice.

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.

Evaluation of left ventricular function using electrocardiographically gated myocardial SPECT with (123)I-labeled fatty acid analog.

PubMed

Nanasato, M; Ando, A; Isobe, S; Nonokawa, M; Hirayama, H; Tsuboi, N; Ito, T; Hirai, M; Yokota, M; Saito, H

2001-12-01

Electrocardiographically (ECG) gated myocardial SPECT with (99m)Tc-tetrofosmin has been used widely to assess left ventricular (LV) function. However, the accuracy of variables using ECG gated myocardial SPECT with beta-methyl-p-(123)I-iodophenylpentadecanoic acid (BMIPP) has not been well defined. Thirty-six patients (29 men, 7 women; mean age, 61.6 +/- 15.6 y) with ischemic heart disease underwent ECG gated myocardial SPECT with (123)I-BMIPP and with (99m)Tc-tetrofosmin and left ventriculography (LVG) within 1 wk. LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), and LV end-systolic volume (LVESV) were determined on gated SPECT using commercially available software for automatic data analysis. These volume-related items on LVG were calculated with an area-length method and were estimated by 2 independent observers to evaluate interobserver validity. The regional wall motion with these methods was assessed visually. LVEF was 41.1% +/- 12.5% on gated SPECT with (123)I-BMIPP, 44.5% +/- 13.1% on gated SPECT with (99m)Tc-tetrofosmin, and 46.0% +/- 12.7% on LVG. Global LV function and regional wall motion between both gated SPECT procedures had excellent correlation (LVEF, r = 0.943; LVEDV, r = 0.934; LVESV, r = 0.952; regional wall motion, kappa = 0.92). However, the correlations of global LV function and regional wall motion between each gated SPECT and LVG were significantly lower. Gated SPECT with (123)I-BMIPP showed the same interobserver validity as gated SPECT with (99m)Tc-tetrofosmin. Gated SPECT with (123)I-BMIPP provides high accuracy with regard to LV function and is sufficiently applicable for use in clinical SPECT. This technique can simultaneously reveal myocardial fatty acid metabolism and LV function, which may be useful to evaluate various cardiac diseases.

Implementation of GPU accelerated SPECT reconstruction with Monte Carlo-based scatter correction.

PubMed

Bexelius, Tobias; Sohlberg, Antti

2018-06-01

Statistical SPECT reconstruction can be very time-consuming especially when compensations for collimator and detector response, attenuation, and scatter are included in the reconstruction. This work proposes an accelerated SPECT reconstruction algorithm based on graphics processing unit (GPU) processing. Ordered subset expectation maximization (OSEM) algorithm with CT-based attenuation modelling, depth-dependent Gaussian convolution-based collimator-detector response modelling, and Monte Carlo-based scatter compensation was implemented using OpenCL. The OpenCL implementation was compared against the existing multi-threaded OSEM implementation running on a central processing unit (CPU) in terms of scatter-to-primary ratios, standardized uptake values (SUVs), and processing speed using mathematical phantoms and clinical multi-bed bone SPECT/CT studies. The difference in scatter-to-primary ratios, visual appearance, and SUVs between GPU and CPU implementations was minor. On the other hand, at its best, the GPU implementation was noticed to be 24 times faster than the multi-threaded CPU version on a normal 128 × 128 matrix size 3 bed bone SPECT/CT data set when compensations for collimator and detector response, attenuation, and scatter were included. GPU SPECT reconstructions show great promise as an every day clinical reconstruction tool.

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.

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.

Liver perfusion imaging in patients with primary and metastatic liver malignancy: prospective comparison between 99mTc-MAA spect and dynamic CT perfusion.

PubMed

Reiner, Caecilia S; Goetti, Robert; Burger, Irene A; Fischer, Michael A; Frauenfelder, Thomas; Knuth, Alexander; Pfammatter, Thomas; Schaefer, Niklaus; Alkadhi, Hatem

2012-05-01

To prospectively analyze the correlation between parameters of liver perfusion from technetium99m-macroaggregates of albumin (99mTc-MAA) single photon emission computed tomography (SPECT) with those obtained from dynamic CT perfusion in patients with primary or metastatic liver malignancy. Twenty-five consecutive patients (11 women, 14 men; mean age 60.9 ± 10.8; range: 32-78 years) with primary (n = 5) or metastatic (n = 20) liver malignancy planned to undergo selective internal radiotherapy underwent dynamic contrast-enhanced CT liver perfusion imaging (four-dimensional spiral mode, scan range 14.8 cm, 15 scans, cycle time 3 seconds) and 99m)Tc-MAA SPECT after intraarterial injection of 180 MBq 99mTc-MAA on the same day. Data were evaluated by two blinded and independent readers for the parameters arterial liver perfusion (ALP), portal venous perfusion (PVP), and total liver perfusion (TLP) from CT, and the 99mTc-MAA uptake-ratio of tumors in relation to normal liver parenchyma from SPECT. Interreader agreements for quantitative perfusion parameters were high for dynamic CT (r = 0.90-0.98, each P < .01) and 99mTc -MAA SPECT (r = 0.91, P < .01). Significant correlation was found between 99mTc-MAA uptake ratio and ALP (r = 0.7, P < .01) in liver tumors. No significant correlation was found between 99mTc-MAA uptake ratio, PVP (r = -0.381, P = .081), and TLP (r = 0.039, P = .862). This study indicates that in patients with primary and metastatic liver malignancy, ALP obtained by dynamic CT liver perfusion significantly correlates with the 99mTc-MAA uptake ratio obtained by SPECT. Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.

Methodological Rigor in Preclinical Cardiovascular Studies

PubMed Central

Ramirez, F. Daniel; Motazedian, Pouya; Jung, Richard G.; Di Santo, Pietro; MacDonald, Zachary D.; Moreland, Robert; Simard, Trevor; Clancy, Aisling A.; Russo, Juan J.; Welch, Vivian A.; Wells, George A.

2017-01-01

Rationale: Methodological sources of bias and suboptimal reporting contribute to irreproducibility in preclinical science and may negatively affect research translation. Randomization, blinding, sample size estimation, and considering sex as a biological variable are deemed crucial study design elements to maximize the quality and predictive value of preclinical experiments. Objective: To examine the prevalence and temporal patterns of recommended study design element implementation in preclinical cardiovascular research. Methods and Results: All articles published over a 10-year period in 5 leading cardiovascular journals were reviewed. Reports of in vivo experiments in nonhuman mammals describing pathophysiology, genetics, or therapeutic interventions relevant to specific cardiovascular disorders were identified. Data on study design and animal model use were collected. Citations at 60 months were additionally examined as a surrogate measure of research impact in a prespecified subset of studies, stratified by individual and cumulative study design elements. Of 28 636 articles screened, 3396 met inclusion criteria. Randomization was reported in 21.8%, blinding in 32.7%, and sample size estimation in 2.3%. Temporal and disease-specific analyses show that the implementation of these study design elements has overall not appreciably increased over the past decade, except in preclinical stroke research, which has uniquely demonstrated significant improvements in methodological rigor. In a subset of 1681 preclinical studies, randomization, blinding, sample size estimation, and inclusion of both sexes were not associated with increased citations at 60 months. Conclusions: Methodological shortcomings are prevalent in preclinical cardiovascular research, have not substantially improved over the past 10 years, and may be overlooked when basing subsequent studies. Resultant risks of bias and threats to study validity have the potential to hinder progress in

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.

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

Experience with single photon emission computerized tomography (SPECT) in follow-up of sternotomy healing.

PubMed

Harjula, A; Järvinen, A; Mattila, S; Porkka, L

1985-01-01

Single photon emission computerized tomography (SPECT) was performed thrice in ten patients undergoing open-heart surgery--preoperatively and 2 and 12 weeks postoperatively. The operations were done for ischemic heart disease (5), aortic valvular stenosis (2), aortic valvular insufficiency (1), leaking mitral prosthetic valve (1) and combined aortic and mitral valvular stenosis and insufficiency (1). The healing process in the longitudinally divided sternum was evaluated from the SPECT study. Four conventional static images in two dimensions were registered in anteroposterior, posteroanterior and left and right lateral projections. A tomographic study was done. Quantitative analyses were performed. The ratio of the sternal counts to the counts from a thoracic vertebra was calculated for use as a reference. The activity ratios showed a similar pattern in six cases, with initial increases and at 12 weeks slight decrease compared with the preoperative values. In two cases the activity was still increasing after 12 postoperative weeks. One patient, with sternotomy also one year previously, showed only slightly increased activity. The activity at the areas of the sternal wires was increased in six cases. The study thus revealed differing patterns of isotope uptake, although recovery was uneventful in all patients. The differences may reflect the possibility that the operative course and the preoperative clinical status can influence the healing mechanisms.

Mitigating risk in academic preclinical drug discovery

PubMed Central

Dahlin, Jayme L.; Inglese, James; Walters, Michael A.

2018-01-01

The number of academic drug discovery centres has grown considerably in recent years, providing new opportunities to couple the curiosity-driven research culture in academia with rigorous preclinical drug discovery practices used in industry. To fully realize the potential of these opportunities, it is important that academic researchers understand the risks inherent in preclinical drug discovery, and that translational research programmes are effectively organized and supported at an institutional level. In this article, we discuss strategies to mitigate risks in several key aspects of preclinical drug discovery at academic drug discovery centres, including organization, target selection, assay design, medicinal chemistry and preclinical pharmacology. PMID:25829283

Simultaneous Tc-99m and I-123 dual-radionuclide imaging with a solid-state detector-based brain-SPECT system and energy-based scatter correction.

PubMed

Takeuchi, Wataru; Suzuki, Atsuro; Shiga, Tohru; Kubo, Naoki; Morimoto, Yuichi; Ueno, Yuichiro; Kobashi, Keiji; Umegaki, Kikuo; Tamaki, Nagara

2016-12-01

A brain single-photon emission computed tomography (SPECT) system using cadmium telluride (CdTe) solid-state detectors was previously developed. This CdTe-SPECT system is suitable for simultaneous dual-radionuclide imaging due to its fine energy resolution (6.6 %). However, the problems of down-scatter and low-energy tail due to the spectral characteristics of a pixelated solid-state detector should be addressed. The objective of this work was to develop a system for simultaneous Tc-99m and I-123 brain studies and evaluate its accuracy. A scatter correction method using five energy windows (FiveEWs) was developed. The windows are Tc-lower, Tc-main, shared sub-window of Tc-upper and I-lower, I-main, and I-upper. This FiveEW method uses pre-measured responses for primary gamma rays from each radionuclide to compensate for the overestimation of scatter by the triple-energy window method that is used. Two phantom experiments and a healthy volunteer experiment were conducted using the CdTe-SPECT system. A cylindrical phantom and a six-compartment phantom with five different mixtures of Tc-99m and I-123 and a cold one were scanned. The quantitative accuracy was evaluated using 18 regions of interest for each phantom. In the volunteer study, five healthy volunteers were injected with Tc-99m human serum albumin diethylene triamine pentaacetic acid (HSA-D) and scanned (single acquisition). They were then injected with I-123 N-isopropyl-4-iodoamphetamine hydrochloride (IMP) and scanned again (dual acquisition). The counts of the Tc-99m images for the single and dual acquisitions were compared. In the cylindrical phantom experiments, the percentage difference (PD) between the single and dual acquisitions was 5.7 ± 4.0 % (mean ± standard deviation). In the six-compartment phantom experiment, the PDs between measured and injected activity for Tc-99m and I-123 were 14.4 ± 11.0 and 2.3 ± 1.8 %, respectively. In the volunteer study, the PD between the single

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

Geometric Characterization of Multi-Axis Multi-Pinhole SPECT

PubMed Central

DiFilippo, Frank P.

2008-01-01

A geometric model and calibration process are developed for SPECT imaging with multiple pinholes and multiple mechanical axes. Unlike the typical situation where pinhole collimators are mounted directly to rotating gamma ray detectors, this geometric model allows for independent rotation of the detectors and pinholes, for the case where the pinhole collimator is physically detached from the detectors. This geometric model is applied to a prototype small animal SPECT device with a total of 22 pinholes and which uses dual clinical SPECT detectors. All free parameters in the model are estimated from a calibration scan of point sources and without the need for a precision point source phantom. For a full calibration of this device, a scan of four point sources with 360° rotation is suitable for estimating all 95 free parameters of the geometric model. After a full calibration, a rapid calibration scan of two point sources with 180° rotation is suitable for estimating the subset of 22 parameters associated with repositioning the collimation device relative to the detectors. The high accuracy of the calibration process is validated experimentally. Residual differences between predicted and measured coordinates are normally distributed with 0.8 mm full width at half maximum and are estimated to contribute 0.12 mm root mean square to the reconstructed spatial resolution. Since this error is small compared to other contributions arising from the pinhole diameter and the detector, the accuracy of the calibration is sufficient for high resolution small animal SPECT imaging. PMID:18293574

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

A quantitative analysis of statistical power identifies obesity end points for improved in vivo preclinical study design.

PubMed

Selimkhanov, J; Thompson, W C; Guo, J; Hall, K D; Musante, C J

2017-08-01

The design of well-powered in vivo preclinical studies is a key element in building the knowledge of disease physiology for the purpose of identifying and effectively testing potential antiobesity drug targets. However, as a result of the complexity of the obese phenotype, there is limited understanding of the variability within and between study animals of macroscopic end points such as food intake and body composition. This, combined with limitations inherent in the measurement of certain end points, presents challenges to study design that can have significant consequences for an antiobesity program. Here, we analyze a large, longitudinal study of mouse food intake and body composition during diet perturbation to quantify the variability and interaction of the key metabolic end points. To demonstrate how conclusions can change as a function of study size, we show that a simulated preclinical study properly powered for one end point may lead to false conclusions based on secondary end points. We then propose the guidelines for end point selection and study size estimation under different conditions to facilitate proper power calculation for a more successful in vivo study design.

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.

Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols.

PubMed

Verger, Antoine; Djaballah, Wassila; Fourquet, Nicolas; Rouzet, François; Koehl, Grégoire; Imbert, Laetitia; Poussier, Sylvain; Fay, Renaud; Roch, Véronique; Le Guludec, Dominique; Karcher, Gilles; Marie, Pierre-Yves

2013-02-01

The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving (201)Tl (n = 120) or (99m)Tc-sestamibi injected at low dose at stress ((99m)Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ((99m)Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, (201)Tl 92 %, (99m)Tc-Low 86 %, (99m)Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p < 0.001). This larger extent was mainly observed in 50 obese patients who were in the (201)Tl or (99m)Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 ± 101 kcounts) and dramatically enhanced with CZT SPECT (+279 ± 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT.

Preclinical Testing of a Translocator Protein Ligand for the Treatment of Amyotrophic Lateral Sclerosis

DTIC Science & Technology

2017-03-01

Accessed October 26, 2015]. Barneoud, P. et al., 1997. Quantitative motor assessment in FALS mice: a longitudinal study . Neuroreport, 8, pp.2861–2865...cell study , we found that PK acts directly on motor neurons to prevent their death, not via the astrocytes. Then, we evidenced that PK protects not...in TSPO content may protect motor neurons against ALS. Second, in our preclinical study in ALS mice, we have determined that the best route to

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

Quantitative multimodality imaging in cancer research and therapy.

PubMed

Yankeelov, Thomas E; Abramson, Richard G; Quarles, C Chad

2014-11-01

Advances in hardware and software have enabled the realization of clinically feasible, quantitative multimodality imaging of tissue pathophysiology. Earlier efforts relating to multimodality imaging of cancer have focused on the integration of anatomical and functional characteristics, such as PET-CT and single-photon emission CT (SPECT-CT), whereas more-recent advances and applications have involved the integration of multiple quantitative, functional measurements (for example, multiple PET tracers, varied MRI contrast mechanisms, and PET-MRI), thereby providing a more-comprehensive characterization of the tumour phenotype. The enormous amount of complementary quantitative data generated by such studies is beginning to offer unique insights into opportunities to optimize care for individual patients. Although important technical optimization and improved biological interpretation of multimodality imaging findings are needed, this approach can already be applied informatively in clinical trials of cancer therapeutics using existing tools. These concepts are discussed herein.

Imaging Lung Function in Mice Using SPECT/CT and Per-Voxel Analysis

PubMed Central

Jobse, Brian N.; Rhem, Rod G.; McCurry, Cory A. J. R.; Wang, Iris Q.; Labiris, N. Renée

2012-01-01

Chronic lung disease is a major worldwide health concern but better tools are required to understand the underlying pathologies. Ventilation/perfusion (V/Q) single photon emission computed tomography (SPECT) with per-voxel analysis allows for non-invasive measurement of regional lung function. A clinically adapted V/Q methodology was used in healthy mice to investigate V/Q relationships. Twelve week-old mice were imaged to describe normal lung function while 36 week-old mice were imaged to determine how age affects V/Q. Mice were ventilated with Technegas™ and injected with 99mTc-macroaggregated albumin to trace ventilation and perfusion, respectively. For both processes, SPECT and CT images were acquired, co-registered, and quantitatively analyzed. On a per-voxel basis, ventilation and perfusion were moderately correlated (R = 0.58±0.03) in 12 week old animals and a mean log(V/Q) ratio of −0.07±0.01 and standard deviation of 0.36±0.02 were found, defining the extent of V/Q matching. In contrast, 36 week old animals had significantly increased levels of V/Q mismatching throughout the periphery of the lung. Measures of V/Q were consistent across healthy animals and differences were observed with age demonstrating the capability of this technique in quantifying lung function. Per-voxel analysis and the ability to non-invasively assess lung function will aid in the investigation of chronic lung disease models and drug efficacy studies. PMID:22870297

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

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.

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.

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.

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

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 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

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.

[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.

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.

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.

Voxel-by-voxel analysis of brain SPECT perfusion in Fibromyalgia

NASA Astrophysics Data System (ADS)

Guedj, Eric; Taïeb, David; Cammilleri, Serge; Lussato, David; de Laforte, Catherine; Niboyet, Jean; Mundler, Olivier

2007-02-01

We evaluated brain perfusion SPECT at rest, without noxious stiumuli, in a homogeneous group of hyperalgesic FM patients. We performed a voxel-based analysis in comparison to a control group, matched for age and gender. Under such conditions, we made the assumption that significant cerebral perfusion abnormalities could be demonstrated, evidencing altered cerebral processing associated with spontaneous pain in FM patients. The secondary objective was to study the reversibility and the prognostic value of such possible perfusion abnormalities under specific treatment. Eighteen hyperalgesic FM women (mean age 48 yr; range 25-63 yr; ACR criteria) and 10 healthy women matched for age were enrolled in the study. A voxel-by-voxel group analysis was performed using SPM2 ( p<0.05, corrected for multiple comparisons). All brain SPECT were performed before any change was made in therapy in the pain care unit. A second SPECT was performed a month later after specific treatment by Ketamine. Compared to control subjects, we observed individual brain SPECT abnormalities in FM patients, confirmed by SPM2 analysis with hyperperfusion of the somatosensory cortex and hypoperfusion of the frontal, cingulate, medial temporal and cerebellar cortices. We also found that a medial frontal and anterior cingulate hypoperfusions were highly predictive (PPV=83%; NPV=91%) of non-response on Ketamine, and that only responders showed significant modification of brain perfusion, after treatment. In the present study performed without noxious stimuli in hyperalgesic FM patients, we found significant hyperperfusion in regions of the brain known to be involved in sensory dimension of pain processing and significant hypoperfusion in areas assumed to be associated with the affective dimension. As current pharmacological and non-pharmacological therapies act differently on both components of pain, we hypothesize that SPECT could be a valuable and readily available tool to guide individual therapeutic

Comparison of LVEF assessed by 2D echocardiography, gated blood pool SPECT, 99mTc tetrofosmin gated SPECT, and 18F-FDG gated PET with ERNV in patients with CAD and severe LV dysfunction.

PubMed

Raja, Senthil; Mittal, Bhagwant R; Santhosh, Sampath; Bhattacharya, Anish; Rohit, Manoj K

2014-11-01

Left ventricular ejection fraction (LVEF) is the single most important predictor of prognosis in patients with coronary artery disease (CAD) and left ventricular (LV) dysfunction. Equilibrium radionuclide ventriculography (ERNV) is considered the most reliable technique for assessing LVEF. Most of these patients undergo two dimensional (2D) echocardiography and myocardial viability study using gated myocardial perfusion imaging (MPI) or gated F-fluorodeoxyglucose (F-FDG) PET. However, the accuracy of LVEF assessed by these methods is not clear. This study has been designed to assess the correlation and agreement between the LVEF measured by 2D echocardiography, gated blood pool single photon emission computed tomography (SPECT), Tc tetrofosmin gated SPECT, and F-FDG gated PET with ERNV in CAD patients with severe LV dysfunction. Patients with CAD and severe LV dysfunction [ejection fraction (EF) <35 assessed by 2D echocardiography] were prospectively included in the study. These patients underwent ERNV along with gated blood pool SPECT, Tc tetrofosmin gated SPECT, and F-FDG gated PET as per the standard protocol for myocardial viability assessment and LVEF calculation. Spearman's coefficient of correlation (r) was calculated for the different sets of values with significance level kept at a P-value less than 0.05. Bland-Altman plots were inspected to visually assess the between-agreement measurements from different methods. Forty-one patients were prospectively included. LVEF calculated by various radionuclide methods showed good correlation with ERNV as follows: gated blood pool SPECT, r=0.92; MPI gated SPECT, r=0.85; and F-FDG gated PET, r=0.76. However, the correlation between 2D echocardiography and ERNV was poor (r=0.520). The Bland-Altman plot for LVEF measured by all radionuclide methods showed good agreement with ERNV. However, agreement between 2D echocardiography and ERNV is poor, as most of the values in this plot gave a negative difference for low EF

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.

Psychometric Properties of Depression Anxiety and Stress in Preclinical Medical Students.

PubMed

Nimkuntod, Porntip; Uengarpon, Naporn; Benjaoran, Fuangfa; Pinwanna, Kwanruan; Ratanakeereepun, Karakad; Tongdee, Pattama

2016-10-01

Medical education and learning outcomes might adversely affect students’ mental health in all axes depression, anxiety, and stress. Faculty has a concern regarding the mental well-being of the medical students. Explore the prevalence of depressive anxiety and stress symptoms, ways of coping, and their relationships to variables among preclinical medical students. A cross-sectional, observational study was conducted in preclinical medical students, Suranaree University of Technology in March 2015. Two hundred thirty medical students (First, second, and third year students) were included and then completed the Self-administered questionnaire, The Depression Anxiety Stress Scale-21 (DASS-21) is a quantitatively measured for distress along the three axes of depression, anxiety, and stress. At the beginning of the study, 230 students enrolled in the study (43.2% male). The overall response rate among medical students was 92.61% (213/230). The prevalence of mild to moderate degree in depression, anxiety, and stress level was 9.4%, 22.5%, and 5.6%, respectively while the prevalence of severe to extremely severe degree in depression, anxiety, and stress level was 0.9%, 3.2%, and 0%, respectively. The second-year medical students exhibited the highest percentage of depression, anxiety, and stress but there was no significant difference among depression, anxiety, and stress between academic year in preclinical medical students. No burnout and suicidal ideation were reported by either males or females. This present indicated that medical students have a low level of depression, anxiety, and stress, however, the data is useful for further planning of prevention in psychometric risks.

Reconstruction of multiple-pinhole micro-SPECT data using origin ensembles.

PubMed

Lyon, Morgan C; Sitek, Arkadiusz; Metzler, Scott D; Moore, Stephen C

2016-10-01

methods showed decreased reconstruction time and no loss of performance when compared to conventional OE alone. OE-reconstructed images were found to be quantitatively and qualitatively similar to MLEM, yet OE also provided estimates of image uncertainty. Some acceleration of the reconstruction can be gained through the use of parallel computing. The OE algorithm is useful for reconstructing multiple-pinhole SPECT data and can be easily modified for real-time reconstruction.

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

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.

Systematic evaluation of tumoral 99mTc-MAA uptake using SPECT and SPECT/CT in 502 patients before 90Y radioembolization.

PubMed

Ilhan, Harun; Goritschan, Anna; Paprottka, Phillip; Jakobs, Tobias F; Fendler, Wolfgang P; Bartenstein, Peter; Hacker, Marcus; Haug, Alexander R

2015-03-01

The aim of this study was to evaluate the (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) uptake of primary and secondary liver tumors in a large patient cohort before (90)Y radioembolization. We included 502 patients during the years 2005-2013 (55% male; mean age, 62 ± 11 y), who were examined with (99m)Tc-MAA SPECT or SPECT/CT before planned radioembolization. The patients had colorectal cancer (CRC; n = 195, 38.8%), neuroendocrine tumors (NET; n = 77, 15.3%), mammary cancer (MAM; n = 68, 13.5%), hepatocellular carcinoma (HCC; n = 59, 11.8%), cholangiocellular carcinoma (CCC; n = 40, 8.0%), or urologic tumors (URO; n = 14, 2.8%). SPECT with coregistered contrast-enhanced CT or MR imaging and SPECT/CT images of these patients were analyzed using dedicated software with regard to the (99m)Tc-MAA uptake of the liver tumors. Regions of interest were drawn around the lesions manually and quantified the uptake of up to 3 lesions per patient and also adjacent healthy liver tissue without evidence of tumor. We quantified maximum and mean counts per pixel and calculated tumor-to-background ratio (TBR). Data are reported as mean ± SD. Lesion uptake was classified as being homogeneously high (grade 1), heterogeneously high (grade 2), equal to that of the liver (grade 3), or low (grade 4). Grade 1 uptake was seen in 230 of 1,008 lesions (with the highest rates in sarcoma [47%], MAM [37%], and NET [32%]), grade 2 in 706 lesions (with the highest rates in CRC [77%], HCC [75%], and CCC [74%]), grade 4 in 57 lesions (with the highest rates in pancreatic cancer [17%], sarcoma [SAR] [13%], and MAM [8%]), and grade 3 in only 15 lesions. In quantitative analysis, the mean TBRmax of all lesions was 4.8 ± 4.1 (range, 0.2-50.1), with the highest values in HCC (6.0 ± 4.7; range, 1.4-21.6), NET (5.4 ± 4.9; range, 0.8-43.0), pancreatic cancer (4.0 ± 2.8; range, 0.9-12.2), and CCC (4.7 ± 2.9; range, 0.9-11.6), and the lowest values in SAR (3.5 ± 1.8; range, 0.8-2.7) and MAM (3.6 ± 2

Case Report: SPECT/CT as the New Diagnostic Tool for Specific Wrist Pathology.

PubMed

Linde, Musters; Ten Broek, M; Kraan, G A

2017-01-01

Single photon emission computed tomography has been introduced as a promising new diagnostic tool in orthopaedic pathology since the early 90'. Computed tomography, the combined with SPECT, gives insight in the specific sight of wrist pathology. Literature already supports introduction of SPECT/CT in wrist pathology, but clinical application is lagging. A 40yr old patient reported first in 2004 with persisting pain after a right distal radius fracture. Several diagnostics and operative interventions were performed, all unsuccessful. Because of the persisting pain a SPECT-CT was performed which showed a cyst in the hamate bone, which was successfully enucleated. The patient was finally pain free at recent follow-up. With a QDash-score of 43 and a PRW (H) E-DLV-score of 58/150. In this case report, SPECT/CT proved a very sensitive diagnostic tool for specific pathology of the wrist. It offered precise localisation and thereby the clinically suspected diagnosis was confirmed and the patient successfully treated.

"Parkinson-dementia" diseases: a comparison by double tracer SPECT studies.

PubMed

Rossi, Carlo; Volterrani, Duccio; Nicoletti, Valentina; Manca, Gianpiero; Frosini, Daniela; Kiferle, Lorenzo; Unti, Elisa; De Feo, Paola; Bonuccelli, Ubaldo; Ceravolo, Roberto

2009-12-01

We performed 123I-FP-CIT/SPECT and ECD/SPECT in 30 patients with Parkinson's disease with dementia (PDD) and 30 patients with dementia with Lewy bodies (DLB) to evaluate whether presynaptic nigro-striatal function and/or cerebral perfusional pattern is different in these diseases. The striatal uptake of DAT tracer was statistically significantly lower in PDD and DLB with respect to control data (p < 0.0005), however no significant difference was found between PDD and DLB. Patients with PDD and DLB showed a significant reduction of rCBF (p < 0.001) in parieto-occipital and frontal areas, with respect to controls, but the comparison between the two groups did not result in any significant difference by SPM analysis. Finally no correlation was found between any regional perfusional changes and nigro-striatal dysfunction. We conclude that neither studies with 123I-FP-CIT nor ECD/SPECT were able to discriminate between DLB and PDD in vivo.

WE-H-206-03: Promises and Challenges of Benchtop X-Ray Fluorescence CT (XFCT) for Quantitative in Vivo Imaging

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

Cho, S.

-modality imaging instrumentation and techniques that are being developed. Sang Hyun Cho; X-ray fluorescence (XRF) imaging, such as x-ray fluorescence computed tomography (XFCT), offers unique capabilities for accurate identification and quantification of metals within the imaging objects. As a result, it has emerged as a promising quantitative imaging modality in recent years, especially in conjunction with metal-based imaging probes. This talk will familiarize the audience with the basic principles of XRF/XFCT imaging. It will also cover the latest development of benchtop XFCT technology. Additionally, the use of metallic nanoparticles such as gold nanoparticles, in conjunction with benchtop XFCT, will be discussed within the context of preclinical multimodal multiplexed molecular imaging. Learning Objectives: To learn the basic principles of XRF/XFCT imaging To learn the latest advances in benchtop XFCT development for preclinical imaging Funding support received from NIH and DOD; Funding support received from GE Healthcare; Funding support received from Siemens AX; Patent royalties received from GE Healthcare; L. Wang, Funding Support: NIH; COI: Microphotoacoustics; S. Cho, Yes: ;NIH/NCI grant R01CA155446 DOD/PCRP grant W81XWH-12-1-0198.« less

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

High Resolution Spatio Temporal Moments Analysis of Solute Migration Captured using Pre-clinical Medical Imaging Techniques

NASA Astrophysics Data System (ADS)

Dogan, M.; Moysey, S. M.; Powell, B. A.; DeVol, T. A.

2016-12-01

Advances in medical imaging technologies are continuously expanding the range of applications enabled within the earth sciences. While computed x-ray tomography (CT) scans have traditionally been used for investigating the structure of geologic materials, it is now possible to perform 3D time-lapse imaging of dynamic processes, such as monitoring the infiltration of water into a soil, with sub-millimeter resolution. Likewise, single photon emission computed tomography (SPECT) can provide information on the evolution of solute transport with spatial resolution on the order of a millimeter by tracking the migration of gamma-ray emitting isotopes like 99mTc and 111In. While these imaging techniques are revolutionizing our ability to look within porous media, techniques for the analysis of such rich and large data sets are limited. The spatial and temporal moments of a plume have long been used to provide quantitative measures to describe plume movement in a wide range of settings from the lab to field. Moment analysis can also be used to estimate the hydrologic properties of the porous media. In this research, we investigate the use of moments for analyzing a high resolution 4D SPECT data set collected during a 99mTc transport experiment performed in a heterogeneous column. The 4D nature of the data set makes it amenable to the use of data mining and pattern recognition methods, such as cluster analysis, to identify regions or zones within the data that exhibit abnormal or unexpected behaviors. We then compare anomalous features within the SPECT data to similar features identified within the CT image to relate the flow behavior to pore-scale structures, such as porosity differences and macropores. Such comparisons help to identify whether these features are good predictors of preferential transport. Likewise, we evaluate whether local analysis of moments can be used to infer apparent parameters governing non-conservative transport in a heterogeneous porous media, such

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

Clinical Utility of SPECT Neuroimaging in the Diagnosis and Treatment of Traumatic Brain Injury: A Systematic Review

PubMed Central

Raji, Cyrus A.; Tarzwell, Robert; Pavel, Dan; Schneider, Howard; Uszler, Michael; Thornton, John; van Lierop, Muriel; Cohen, Phil; Amen, Daniel G.; Henderson, Theodore

2014-01-01

Purpose This systematic review evaluated the clinical utility of single photon emission computed tomography (SPECT) in traumatic brain injury (TBI). Methods After defining a PICO Statement (Population, Intervention, Comparison and Outcome Statement), PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria were applied to identify 1600 articles. After screening, 374 articles were eligible for review. Inclusion for review was focus on SPECT in the setting of mild, moderate, or severe TBI with cerebral lobar specificity of SPECT findings. Other inclusion criteria were comparison modalities in the same subjects and articles in English. Foreign language articles, SPECT studies that did not include comparison modalities, and case reports were not included for review. Results We identified 19 longitudinal and 52 cross-sectional studies meeting inclusion criteria. Three longitudinal studies examined diagnostic predictive value. The first showed positive predictive value increases from initial SPECT scan shortly after trauma to one year follow up scans, from 59% to 95%. Subsequent work replicated these results in a larger cohort. Longitudinal and cross sectional studies demonstrated SPECT lesion localization not detected by CT or MRI. The most commonly abnormal regions revealed by SPECT in cross-sectional studies were frontal (94%) and temporal (77%) lobes. SPECT was found to outperform both CT and MRI in both acute and chronic imaging of TBI, particularly mild TBI. It was also found to have a near 100% negative predictive value. Conclusions This review demonstrates Level IIA evidence (at least one non-randomized controlled trial) for the value of SPECT in TBI. Given its advantages over CT and MRI in the detection of mild TBI in numerous studies of adequate quality, and given its excellent negative predictive value, it may be an important second test in settings where CT or MRI are negative after a closed head injury with post

Clinical utility of SPECT neuroimaging in the diagnosis and treatment of traumatic brain injury: a systematic review.

PubMed

Raji, Cyrus A; Tarzwell, Robert; Pavel, Dan; Schneider, Howard; Uszler, Michael; Thornton, John; van Lierop, Muriel; Cohen, Phil; Amen, Daniel G; Henderson, Theodore

2014-01-01

This systematic review evaluated the clinical utility of single photon emission computed tomography (SPECT) in traumatic brain injury (TBI). After defining a PICO Statement (Population, Intervention, Comparison and Outcome Statement), PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria were applied to identify 1600 articles. After screening, 374 articles were eligible for review. Inclusion for review was focus on SPECT in the setting of mild, moderate, or severe TBI with cerebral lobar specificity of SPECT findings. Other inclusion criteria were comparison modalities in the same subjects and articles in English. Foreign language articles, SPECT studies that did not include comparison modalities, and case reports were not included for review. We identified 19 longitudinal and 52 cross-sectional studies meeting inclusion criteria. Three longitudinal studies examined diagnostic predictive value. The first showed positive predictive value increases from initial SPECT scan shortly after trauma to one year follow up scans, from 59% to 95%. Subsequent work replicated these results in a larger cohort. Longitudinal and cross sectional studies demonstrated SPECT lesion localization not detected by CT or MRI. The most commonly abnormal regions revealed by SPECT in cross-sectional studies were frontal (94%) and temporal (77%) lobes. SPECT was found to outperform both CT and MRI in both acute and chronic imaging of TBI, particularly mild TBI. It was also found to have a near 100% negative predictive value. This review demonstrates Level IIA evidence (at least one non-randomized controlled trial) for the value of SPECT in TBI. Given its advantages over CT and MRI in the detection of mild TBI in numerous studies of adequate quality, and given its excellent negative predictive value, it may be an important second test in settings where CT or MRI are negative after a closed head injury with post-injury neurological or psychiatric symptoms.

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

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.

Receiver-operating-characteristic analysis of an automated program for analyzing striatal uptake of 123I-ioflupane SPECT images: calibration using visual reads.

PubMed

Kuo, Phillip Hsin; Avery, Ryan; Krupinski, Elizabeth; Lei, Hong; Bauer, Adam; Sherman, Scott; McMillan, Natalie; Seibyl, John; Zubal, George

2013-03-01

A fully automated objective striatal analysis (OSA) program that quantitates dopamine transporter uptake in subjects with suspected Parkinson's disease was applied to images from clinical (123)I-ioflupane studies. The striatal binding ratios or alternatively the specific binding ratio (SBR) of the lowest putamen uptake was computed, and receiver-operating-characteristic (ROC) analysis was applied to 94 subjects to determine the best discriminator using this quantitative method. Ninety-four (123)I-ioflupane SPECT scans were analyzed from patients referred to our clinical imaging department and were reconstructed using the manufacturer-supplied reconstruction and filtering parameters for the radiotracer. Three trained readers conducted independent visual interpretations and reported each case as either normal or showing dopaminergic deficit (abnormal). The same images were analyzed using the OSA software, which locates the striatal and occipital structures and places regions of interest on the caudate and putamen. Additionally, the OSA places a region of interest on the occipital region that is used to calculate the background-subtracted SBR. The lower SBR of the 2 putamen regions was taken as the quantitative report. The 33 normal (bilateral comma-shaped striata) and 61 abnormal (unilateral or bilateral dopaminergic deficit) studies were analyzed to generate ROC curves. Twenty-nine of the scans were interpreted as normal and 59 as abnormal by all 3 readers. For 12 scans, the 3 readers did not unanimously agree in their interpretations (discordant). The ROC analysis, which used the visual-majority-consensus interpretation from the readers as the gold standard, yielded an area under the curve of 0.958 when using 1.08 as the threshold SBR for the lowest putamen. The sensitivity and specificity of the automated quantitative analysis were 95% and 89%, respectively. The OSA program delivers SBR quantitative values that have a high sensitivity and specificity, compared

Impact of basal inferolateral scar burden determined by automatic analysis of 99mTc-MIBI myocardial perfusion SPECT on the long-term prognosis of cardiac resynchronization therapy.

PubMed

Morishima, Itsuro; Okumura, Kenji; Tsuboi, Hideyuki; Morita, Yasuhiro; Takagi, Kensuke; Yoshida, Ruka; Nagai, Hiroaki; Tomomatsu, Toshiro; Ikai, Yoshihiro; Terada, Kazushi; Sone, Takahito; Murohara, Toyoaki

2017-04-01

Left-ventricular (LV) scarring may be associated with a poor response to cardiac resynchronization therapy (CRT). The automatic analysis of myocardial perfusion single-photon emission computed tomography (MP-SPECT) may provide objective quantification of LV scarring. We investigated the impact of LV scarring determined by an automatic analysis of MP-SPECT on short-term LV volume response as well as long-term outcome. We studied consecutive 51 patients who were eligible to undergo 99mTc-MIBI MP-SPECT both at baseline and 6 months after CRT (ischaemic cardiomyopathies 31%). Quantitative perfusion SPECT was used to evaluate the defect extent (an index of global scarring) and the LV 17-segment regional uptake ratio (an inverse index of regional scar burden). The primary outcome was the composite of overall mortality or first hospitalization for worsening heart failure. A high global scar burden and a low mid/basal inferolateral regional uptake ratio were associated with volume non-responders to CRT at 6 months. The basal inferolateral regional uptake ratio remained as a predictor of volume non-response after adjusting for the type of cardiomyopathy. During a median follow-up of 36.1 months, the outcome occurred in 28 patients. The patients with a low basal inferolateral regional uptake ratio with a cutoff value of 57% showed poor prognosis (log-rank P= 0.006). The scarring determined by automatic analysis of MP-SPECT images may predict a poor response to CRT regardless of the pathogenesis of cardiomyopathy. The basal inferolateral scar burden in particular may have an adverse impact on long-term prognosis. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Effects of CT-based attenuation correction of rat microSPECT images on relative myocardial perfusion and quantitative tracer uptake

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

Strydhorst, Jared H., E-mail: jared.strydhorst@gmail.com; Ruddy, Terrence D.; Wells, R. Glenn

2015-04-15

Purpose: Our goal in this work was to investigate the impact of CT-based attenuation correction on measurements of rat myocardial perfusion with {sup 99m}Tc and {sup 201}Tl single photon emission computed tomography (SPECT). Methods: Eight male Sprague-Dawley rats were injected with {sup 99m}Tc-tetrofosmin and scanned in a small animal pinhole SPECT/CT scanner. Scans were repeated weekly over a period of 5 weeks. Eight additional rats were injected with {sup 201}Tl and also scanned following a similar protocol. The images were reconstructed with and without attenuation correction, and the relative perfusion was analyzed with the commercial cardiac analysis software. The absolutemore » uptake of {sup 99m}Tc in the heart was also quantified with and without attenuation correction. Results: For {sup 99m}Tc imaging, relative segmental perfusion changed by up to +2.1%/−1.8% as a result of attenuation correction. Relative changes of +3.6%/−1.0% were observed for the {sup 201}Tl images. Interscan and inter-rat reproducibilities of relative segmental perfusion were 2.7% and 3.9%, respectively, for the uncorrected {sup 99m}Tc scans, and 3.6% and 4.3%, respectively, for the {sup 201}Tl scans, and were not significantly affected by attenuation correction for either tracer. Attenuation correction also significantly increased the measured absolute uptake of tetrofosmin and significantly altered the relationship between the rat weight and tracer uptake. Conclusions: Our results show that attenuation correction has a small but statistically significant impact on the relative perfusion measurements in some segments of the heart and does not adversely affect reproducibility. Attenuation correction had a small but statistically significant impact on measured absolute tracer uptake.« less

Decreased Lung Perfusion After Breast/Chest Wall Irradiation: Quantitative Results From a Prospective Clinical Trial

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

Liss, Adam L., E-mail: adamliss68@gmail.com; Marsh, Robin B.; Kapadia, Nirav S.

Purpose: To quantify lung perfusion changes after breast/chest wall radiation therapy (RT) using pre- and post-RT single photon emission computed tomography/computed tomography (SPECT/CT) attenuation-corrected perfusion scans; and correlate decreased perfusion with adjuvant RT dose for breast cancer in a prospective clinical trial. Methods and Materials: As part of an institutional review board–approved trial studying the impact of RT technique on lung function in node-positive breast cancer, patients received breast/chest wall and regional nodal irradiation including superior internal mammary node RT to 50 to 52.2 Gy with a boost to the tumor bed/mastectomy scar. All patients underwent quantitative SPECT/CT lung perfusion scanningmore » before RT and 1 year after RT. The SPECT/CT scans were co-registered, and the ratio of decreased perfusion after RT relative to the pre-RT perfusion scan was calculated to allow for direct comparison of SPECT/CT perfusion changes with delivered RT dose. The average ratio of decreased perfusion was calculated in 10-Gy dose increments from 0 to 60 Gy. Results: Fifty patients had complete lung SPECT/CT perfusion data available. No patient developed symptoms consistent with pulmonary toxicity. Nearly all patients demonstrated decreased perfusion in the left lung according to voxel-based analyses. The average ratio of lung perfusion deficits increased for each 10-Gy increment in radiation dose to the lung, with the largest changes in regions of lung that received 50 to 60 Gy (ratio 0.72 [95% confidence interval 0.64-0.79], P<.001) compared with the 0- to 10-Gy region. For each increase in 10 Gy to the left lung, the lung perfusion ratio decreased by 0.06 (P<.001). Conclusions: In the assessment of 50 patients with node-positive breast cancer treated with RT in a prospective clinical trial, decreased lung perfusion by SPECT/CT was demonstrated. Our study allowed for quantification of lung perfusion defects in a prospective

Evaluation of Hospitalized Intractable Epileptic Children with SPECT Scan in Ahvaz, South West of Iran

PubMed Central

Ahmadi, Faramarz; Malekian, Arash; Davoodzadeh, Hannaneh; Kabirinia, Hossein

2016-01-01

Introduction Seizures are the most frequent neurologic disorder seen in childhood. Epilepsy is a group of disorders that includes an abnormally increased susceptibility to seizures. Aim To examine the effectiveness of SPECT (Single Photon Emission Computerized Tomography) in detecting seizure foci in 21 Iranian children who had medically refractory epilepsy. Materials and Methods Children between 2 to 15 years of age with uncontrolled seizures were investigated using SPECT scan as a standardized protocol. Results In 16 cases (76.2%), likely seizure foci were evident, as were seen in the form of decreased regional blood flow, while in 5 cases (23.8%), SPECT scan results were normal. Left temporal lobe was the most common area which had decreased regional blood flow. Conclusion SPECT scan can potentially be used to investigate children with uncontrolled seizures. PMID:27891419

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

Challenges for Preclinical Investigations of Human Biofield Modalities

PubMed Central

Gronowicz, Gloria; Bengston, William

2015-01-01

Preclinical models for studying the effects of the human biofield have great potential to advance our understanding of human biofield modalities, which include external qigong, Johrei, Reiki, therapeutic touch, healing touch, polarity therapy, pranic healing, and other practices. A short history of Western biofield studies using preclinical models is presented and demonstrates numerous and consistent examples of human biofields significantly affecting biological systems both in vitro and in vivo. Methodological issues arising from these studies and practical solutions in experimental design are presented. Important questions still left unanswered with preclinical models include variable reproducibility, dosing, intentionality of the practitioner, best preclinical systems, and mechanisms. Input from the biofield practitioners in the experimental design is critical to improving experimental outcomes; however, the development of standard criteria for uniformity of practice and for inclusion of multiple practitioners is needed. Research in human biofield studies involving preclinical models promises a better understanding of the mechanisms underlying the efficacy of biofield therapies and will be important in guiding clinical protocols and integrating treatments with conventional medical therapies. PMID:26665042

[Performance of Thallium 201 rest-redistribution spect to predict viability in recent myocardial infarction].

PubMed

Coll, Claudia; González, Patricio; Massardo, Teresa; Sierralta, Paulina; Humeres, Pamela; Jofré, Josefina; Yovanovich, Jorge; Aramburú, Ivonne; Brugère, Solange; Chamorro, Hernán; Ramírez, Alfredo; Kunstmann, Sonia; López, Héctor

2002-03-01

The detection of viability after acute myocardial infarction is primordial to select the most appropriate therapy, to decrease cardiac events and abnormal remodeling. Thallium201 SPECT is one of the radionuclide techniques used to detect viability. To evaluate the use of Thallium201 rest-redistribution SPECT to detect myocardial viability in reperfused patients after a recent myocardial infarction. Forty one patients with up to of 24 days of evolution of a myocardial infarction were studied. All had angiographically demonstrated coronary artery disease and were subjected to a successful thrombolysis, angioplasty or bypass grafting. SPECT Thallium201 images were acquired at rest and after 4 h of redistribution. These results were compared with variations in wall motion score, studied at baseline and after 3 or 4 months with echocardiography. The sensitivity of rest-redistribution Thallium201 SPECT, to predict recovery of wall motion was 91% when patient analysis was performed and 79% when segmental analysis was done in the culprit region. The figures for specificity were 56 and 73% respectively. Rest-distribution Thallium201 SPECT has an excellent sensitivity to predict myocardial viability in recent myocardial infarction. The data obtained in this study is similar to that reported for chronic coronary artery disease.

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

A whole-body dual-modality radionuclide optical strategy for preclinical imaging of metastasis and heterogeneous treatment response in different microenvironments.

PubMed

Fruhwirth, Gilbert O; Diocou, Seckou; Blower, Philip J; Ng, Tony; Mullen, Greg E D

2014-04-01

Imaging spontaneous cancer cell metastasis or heterogeneous tumor responses to drug treatment in vivo is difficult to achieve. The goal was to develop a new highly sensitive and reliable preclinical longitudinal in vivo imaging model for this purpose, thereby facilitating discovery and validation of anticancer therapies or molecular imaging agents. The strategy is based on breast cancer cells stably expressing the human sodium iodide symporter (NIS) fused to a red fluorescent protein, thereby permitting radionuclide and fluorescence imaging. Using whole-body nano-SPECT/CT with (99m)TcO4(-), we followed primary tumor growth and spontaneous metastasis in the presence or absence of etoposide treatment. NIS imaging was used to classify organs as small as individual lymph nodes (LNs) to be positive or negative for metastasis, and results were confirmed by confocal fluorescence microscopy. Etoposide treatment efficacy was proven by ex vivo anticaspase 3 staining and fluorescence microscopy. In this preclinical model, we found that the NIS imaging strategy outperformed state-of-the-art (18)F-FDG imaging in its ability to detect small tumors (18.5-fold-better tumor-to-blood ratio) and metastases (LN, 3.6-fold) because of improved contrast in organs close to metastatic sites (12- and 8.5-fold-lower standardized uptake value in the heart and kidney, respectively). We applied the model to assess the treatment response to the neoadjuvant etoposide and found a consistent and reliable improvement in spontaneous metastasis detection. Importantly, we also found that tumor cells in different microenvironments responded in a heterogeneous manner to etoposide treatment, which could be determined only by the NIS-based strategy and not by (18)F-FDG imaging. We developed a new strategy for preclinical longitudinal in vivo cancer cell tracking with greater sensitivity and reliability than (18)F-FDG PET and applied it to track spontaneous and distant metastasis in the presence or absence

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.

Myocardial Perfusion SPECT 2015 in Germany

PubMed Central

Burchert, Wolfgang; Schäfer, Wolfgang; Hacker, Marcus

2016-01-01

Summary Aim The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. Method 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. Results MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1% [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. Conclusion The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring. PMID:27909712

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.

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.

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.

Evaluation of Rigid-Body Motion Compensation in Cardiac Perfusion SPECT Employing Polar-Map Quantification

PubMed Central

Pretorius, P. Hendrik; Johnson, Karen L.; King, Michael A.

2016-01-01

We have recently been successful in the development and testing of rigid-body motion tracking, estimation and compensation for cardiac perfusion SPECT based on a visual tracking system (VTS). The goal of this study was to evaluate in patients the effectiveness of our rigid-body motion compensation strategy. Sixty-four patient volunteers were asked to remain motionless or execute some predefined body motion during an additional second stress perfusion acquisition. Acquisitions were performed using the standard clinical protocol with 64 projections acquired through 180 degrees. All data were reconstructed with an ordered-subsets expectation-maximization (OSEM) algorithm using 4 projections per subset and 5 iterations. All physical degradation factors were addressed (attenuation, scatter, and distance dependent resolution), while a 3-dimensional Gaussian rotator was used during reconstruction to correct for six-degree-of-freedom (6-DOF) rigid-body motion estimated by the VTS. Polar map quantification was employed to evaluate compensation techniques. In 54.7% of the uncorrected second stress studies there was a statistically significant difference in the polar maps, and in 45.3% this made a difference in the interpretation of segmental perfusion. Motion correction reduced the impact of motion such that with it 32.8 % of the polar maps were statistically significantly different, and in 14.1% this difference changed the interpretation of segmental perfusion. The improvement shown in polar map quantitation translated to visually improved uniformity of the SPECT slices. PMID:28042170

The impact of system matrix dimension on small FOV SPECT reconstruction with truncated projections

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

Chan, Chung, E-mail: Chung.Chan@yale.edu, E-mail: Chi.Liu@yale.edu; Wu, Jing; Liu, Chi, E-mail: Chung.Chan@yale.edu, E-mail: Chi.Liu@yale.edu

Purpose: A dedicated cardiac hybrid single photon emission computed tomography (SPECT)/CT scanner that uses cadmium zinc telluride detectors and multiple pinhole collimators for stationary acquisition offers many advantages. However, the impact of the reconstruction system matrix (SM) dimension on the reconstructed image quality from truncated projections and 19 angular samples acquired on this scanner has not been extensively investigated. In this study, the authors aimed to investigate the impact of the dimensions of SM and the use of body contour derived from adjunctive CT imaging as an object support in reconstruction on this scanner, in relation to background extracardiac activity.more » Methods: The authors first simulated a generic SPECT/CT system to image four NCAT phantoms with various levels of extracardiac activity and compared the reconstructions using SM in different dimensions and with/without body contour as a support for quantitative evaluations. The authors then compared the reconstructions of 18 patient studies, which were acquired on a GE Discovery NM570c scanner following injection of different radiotracers, including {sup 99m}Tc-Tetrofosmin and {sup 123}I-mIBG, comparing the scanner’s default SM that incompletely covers the body with a large SM that incorporates a patient specific full body contour. Results: The simulation studies showed that the reconstructions using a SM that only partially covers the body yielded artifacts on the edge of the field of view (FOV), overestimation of activity and increased nonuniformity in the blood pool for the phantoms with higher relative levels of extracardiac activity. However, the impact on the quantitative accuracy in the high activity region, such as the myocardium, was subtle. On the other hand, an excessively large SM that enclosed the entire body alleviated the artifacts and reduced overestimation in the blood pool, but yielded slight underestimation in myocardium and defect regions. The

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.

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

Viewing the functional consequences of traumatic brain injury by using brain SPECT.

PubMed

Pavel, D; Jobe, T; Devore-Best, S; Davis, G; Epstein, P; Sinha, S; Kohn, R; Craita, I; Liu, P; Chang, Y

2006-03-01

High-resolution brain SPECT is increasingly benefiting from improved image processing software and multiple complementary display capabilities. This enables detailed functional mapping of the disturbances in relative perfusion occurring after TBI. The patient population consisted of 26 cases (ages 8-61 years)between 3 months and 6 years after traumatic brain injury.A very strong case can be made for the routine use of Brain SPECT in TBI. Indeed it can provide a detailed evaluation of multiple functional consequences after TBI and is thus capable of supplementing the clinical evaluation and tailoring the therapeutic strategies needed. In so doing it also provides significant additional information beyond that available from MRI/CT. The critical factor for Brain SPECT's clinical relevance is a carefully designed technical protocol, including displays which should enable a comprehensive description of the patterns found, in a user friendly mode.

PET AND SPECT STUDIES IN CHILDREN WITH HEMISPHERIC LOW-GRADE GLIOMAS

PubMed Central

Juhász, Csaba; Bosnyák, Edit

2016-01-01

Molecular imaging is playing an increasing role in the pre-treatment evaluation of low-grade gliomas. While glucose positron emission tomography (PET) can be helpful to differentiate low-grade from high-grade tumors, PET imaging with amino acid radiotracers has several advantages, such as better differentiation between tumors and non-tumorous lesions, optimized biopsy targeting and improved detection of tumor recurrence. This review provides a brief overview of single photon emission computed tomography (SPECT) studies followed by a more detailed review of clinical applications of glucose and amino acid PET imaging in low-grade hemispheric gliomas. We discuss key differences in the performance of the most commonly utilized PET radiotracers and highlight the advantage of PET/MRI fusion to obtain optimal information about tumor extent, heterogeneity and metabolism. Recent data also suggest that simultaneous acquisition of PET/MR images and the combination of advanced MRI techniques with quantitative PET can further improve the pre- and post-treatment evaluation of pediatric brain tumors. PMID:27659825

PET and SPECT studies in children with hemispheric low-grade gliomas.

PubMed

Juhász, Csaba; Bosnyák, Edit

2016-10-01

Molecular imaging is playing an increasing role in the pretreatment evaluation of low-grade gliomas. While glucose positron emission tomography (PET) can be helpful to differentiate low-grade from high-grade tumors, PET imaging with amino acid radiotracers has several advantages, such as better differentiation between tumors and non-tumorous lesions, optimized biopsy targeting, and improved detection of tumor recurrence. This review provides a brief overview of single-photon emission computed tomography (SPECT) studies followed by a more detailed review of the clinical applications of glucose and amino acid PET imaging in low-grade hemispheric gliomas. We discuss key differences in the performance of the most commonly utilized PET radiotracers and highlight the advantage of PET/MRI fusion to obtain optimal information about tumor extent, heterogeneity, and metabolism. Recent data also suggest that simultaneous acquisition of PET/MR images and the combination of advanced MRI techniques with quantitative PET can further improve the pretreatment and post-treatment evaluation of pediatric brain tumors.

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.

Clinical utility of MRI and SPECT in the diagnosis of cognitive impairment referred to memory clinic.

PubMed

Guinane, John; Ng, Boon Lung

2018-05-01

ABSTRACTBackground:Despite of their limited availability and potential for significant variation between and within each modality, this is the first study to prospectively measure the clinical utility of MRI and/or SPECT brain scanning in addition to the routine diagnostic workup of patients presenting to memory clinic. A single center study was conducted over a convenience of 12-month sampling period. For each patient referred for MRI and/or SPECT scanning, the primary geriatrician or psychogeriatrician was asked to assign an initial diagnosis. The initial diagnosis was then compared with the final consensus diagnosis after any scans or neuropsychology testing had been completed. During the 12-month study period, 66 patients (26%) were referred for scans out of a total of 253 patients included in the study. There were 16/44 (36%) positive MRI outcomes and 13/35 (37%) positive SPECT outcomes. The diagnosis changed consistent with the MRI scan findings in 11/44 (25%) and changed consistent with the SPECT scan findings in 9/35 (26%). Potentially reversible pathology was identified in a single patient, 1/50 (2%), via an MRI scan that suggested normal pressure hydrocephalus. The number needed to test for one positive outcome was 3.8 (95% CI 2.0-23.3), 6.0 (95% CI NA), and 1.7 (95% CI 1.3-2.5) for MRI only, SPECT only, and MRI and SPECT together, respectively. The clinical utility of MRI and/or SPECT scanning in this study may be broadly superior to the available international evidence, and further research is needed to identify predictors of positive scan outcomes.

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

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

Monte Carlo evaluation of accuracy and noise properties of two scatter correction methods for /sup 201/Tl cardiac SPECT

NASA Astrophysics Data System (ADS)

Narita, Y.; Iida, H.; Ebert, S.; Nakamura, T.

1997-12-01

Two independent scatter correction techniques, transmission dependent convolution subtraction (TDCS) and triple-energy window (TEW) method, were evaluated in terms of quantitative accuracy and noise properties using Monte Carlo simulation (EGS4). Emission projections (primary, scatter and scatter plus primary) were simulated for three numerical phantoms for /sup 201/Tl. Data were reconstructed with ordered-subset EM algorithm including noise-less transmission data based attenuation correction. Accuracy of TDCS and TEW scatter corrections were assessed by comparison with simulated true primary data. The uniform cylindrical phantom simulation demonstrated better quantitative accuracy with TDCS than with TEW (-2.0% vs. 16.7%) and better S/N (6.48 vs. 5.05). A uniform ring myocardial phantom simulation demonstrated better homogeneity with TDCS than TEW in the myocardium; i.e., anterior-to-posterior wall count ratios were 0.99 and 0.76 with TDCS and TEW, respectively. For the MCAT phantom, TDCS provided good visual and quantitative agreement with simulated true primary image without noticeably increasing the noise after scatter correction. Overall TDCS proved to be more accurate and less noisy than TEW, facilitating quantitative assessment of physiological functions with SPECT.

99mTc-HMPAO SPECT of the brain in mild to moderate traumatic brain injury patients: compared with CT--a prospective study.

PubMed

Nedd, K; Sfakianakis, G; Ganz, W; Uricchio, B; Vernberg, D; Villanueva, P; Jabir, A M; Bartlett, J; Keena, J

1993-01-01

Single photon emission computed tomography (SPECT) with Technetium-99m hexamethyl propylenamine oxime (Tc-99m-HMPAO) was used in 20 patients with mild to moderate traumatic brain injury (TBI) to evaluate the effects of brain trauma on regional cerebral blood flow (rCBF). SPECT scan was compared with CT scan in 16 patients. SPECT showed intraparenchymal differences in rCBF more often than lesions diagnosed with CT scans (87.5% vs. 37.5%). In five of six patients with lesions in both modalities, the area of involvement was relatively larger on SPECT scans than on CT scans. Contrecoup changes were seen in five patients on SPECT alone, two patients with CT alone and one patient had contrecoup lesions on CT and SPECT. Of the eight patients (50%) with skull fractures, seven (43.7%) had rCBF findings on SPECT scan and five (31.3%) demonstrated decrease in rCBF in brain underlying the fracture. All these patients with fractures had normal brain on CT scans. Conversely, extra-axial lesions and fractures evident on CT did not visualize on SPECT, but SPECT demonstrated associated changes in rCBF. Although there is still lack of clinical and pathological correlation, SPECT appears to be a promising method for a more sensitive evaluation of axial lesions in patients with mild to moderate TBI.

In vivo detection of small tumour lesions by multi-pinhole SPECT applying a 99mTc-labelled nanobody targeting the Epidermal Growth Factor Receptor

PubMed Central

Krüwel, Thomas; Nevoltris, Damien; Bode, Julia; Dullin, Christian; Baty, Daniel; Chames, Patrick; Alves, Frauke

2016-01-01

The detection of tumours in an early phase of tumour development in combination with the knowledge of expression of tumour markers such as epidermal growth factor receptor (EGFR) is an important prerequisite for clinical decisions. In this study we applied the anti-EGFR nanobody 99mTc-D10 for visualizing small tumour lesions with volumes below 100 mm3 by targeting EGFR in orthotopic human mammary MDA-MB-468 and MDA-MB-231 and subcutaneous human epidermoid A431 carcinoma mouse models. Use of nanobody 99mTc-D10 of a size as small as 15.5 kDa enables detection of tumours by single photon emission computed tomography (SPECT) imaging already 45 min post intravenous administration with high tumour uptake (>3% ID/g) in small MDA-MB-468 and A431 tumours, with tumour volumes of 52.5 mm3 ± 21.2 and 26.6 mm3 ± 16.7, respectively. Fast blood clearance with a serum half-life of 4.9 min resulted in high in vivo contrast and ex vivo tumour to blood and tissue ratios. In contrast, no accumulation of 99mTc-D10 in MDA-MB-231 tumours characterized by a very low expression of EGFR was observed. Here we present specific and high contrast in vivo visualization of small human tumours overexpressing EGFR by preclinical multi-pinhole SPECT shortly after administration of anti-EGFR nanobody 99mTc-D10. PMID:26912069

CAP--advancing the evaluation of preclinical Alzheimer disease treatments.

PubMed

Reiman, Eric M; Langbaum, Jessica B; Tariot, Pierre N; Lopera, Francisco; Bateman, Randall J; Morris, John C; Sperling, Reisa A; Aisen, Paul S; Roses, Allen D; Welsh-Bohmer, Kathleen A; Carrillo, Maria C; Weninger, Stacie

2016-01-01

If we are to find treatments to postpone, reduce the risk of, or completely prevent the clinical onset of Alzheimer disease (AD), we need faster methods to evaluate promising preclinical AD treatments, new ways to work together in support of common goals, and a determination to expedite the initiation and performance of preclinical AD trials. In this article, we note some of the current challenges, opportunities and emerging strategies in preclinical AD treatment. We describe the Collaboration for Alzheimer's Prevention (CAP)-a convening, harmonizing and consensus-building initiative to help stakeholders advance AD prevention research with rigour, care and maximal impact-and we demonstrate the impact of CAP on the goals and design of new preclinical AD trials.

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

A CZT-based blood counter for quantitative molecular imaging.

PubMed

Espagnet, Romain; Frezza, Andrea; Martin, Jean-Pierre; Hamel, Louis-André; Lechippey, Laëtitia; Beauregard, Jean-Mathieu; Després, Philippe

2017-12-01

Robust quantitative analysis in positron emission tomography (PET) and in single-photon emission computed tomography (SPECT) typically requires the time-activity curve as an input function for the pharmacokinetic modeling of tracer uptake. For this purpose, a new automated tool for the determination of blood activity as a function of time is presented. The device, compact enough to be used on the patient bed, relies on a peristaltic pump for continuous blood withdrawal at user-defined rates. Gamma detection is based on a 20 × 20 × 15 mm 3 cadmium zinc telluride (CZT) detector, read by custom-made electronics and a field-programmable gate array-based signal processing unit. A graphical user interface (GUI) allows users to select parameters and easily perform acquisitions. This paper presents the overall design of the device as well as the results related to the detector performance in terms of stability, sensitivity and energy resolution. Results from a patient study are also reported. The device achieved a sensitivity of 7.1 cps/(kBq/mL) and a minimum detectable activity of 2.5 kBq/ml for 18 F. The gamma counter also demonstrated an excellent stability with a deviation in count rates inferior to 0.05% over 6 h. An energy resolution of 8% was achieved at 662 keV. The patient study was conclusive and demonstrated that the compact gamma blood counter developed has the sensitivity and the stability required to conduct quantitative molecular imaging studies in PET and SPECT.

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

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.

Lung ventilation-perfusion imbalance in pulmonary emphysema: assessment with automated V/Q quotient SPECT.

PubMed

Suga, Kazuyoshi; Kawakami, Yasuhiko; Koike, Hiroaki; Iwanaga, Hideyuki; Tokuda, Osamu; Okada, Munemasa; Matsunaga, Naofumi

2010-05-01

Tc-99m-Technegas-MAA single photon emission computed tomography (SPECT)-derived ventilation (V)/perfusion (Q) quotient SPECT was used to assess lung V-Q imbalance in patients with pulmonary emphysema. V/Q quotient SPECT and V/Q profile were automatically built in 38 patients with pulmonary emphysema and 12 controls, and V/Q distribution and V/Q profile parameters were compared. V/Q distribution on V/Q quotient SPECT was correlated with low attenuation areas (LAA) on density-mask computed tomography (CT). Parameters of V/Q profile such as the median, standard deviation (SD), kurtosis and skewness were proposed to objectively evaluate the severity of lung V-Q imbalance. In contrast to uniform V/Q distribution on V/Q quotient SPECT and a sharp peak with symmetrical V/Q distribution on V/Q profile in controls, lung areas showing heterogeneously high or low V/Q and flattened peaks with broadened V/Q distribution were frequently seen in patients with emphysema, including lung areas with only slight LAA. V/Q distribution was also often asymmetric regardless of symmetric LAA. All the proposed parameters of V/Q profile in entire lungs of patients with emphysema showed large variations compared with controls; SD and kurtosis were significantly different from controls (P < 0.0001 and P < 0.001, respectively), and a significant correlation was found between SD and A-aDO2 (P < 0.0001). V/Q quotient SPECT appears to be more sensitive to detect emphysematous lungs compared with morphologic CT in patients with emphysema. SD and kurtosis of V/Q profile can be adequate parameters to assess the severity of lung V-Q imbalance causing gas-exchange impairment in patients with emphysema.

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.

Regional Cerebral Blood Flow Analysis in Patients with Multiple Sclerosis Using TC-99M Hmpao and a Three - Spect System.

NASA Astrophysics Data System (ADS)

D'Souza, Maximian Felix

1995-01-01

The purpose of the present study was to determine the changes in regional cerebral blood flow (rCBF) with a cognitive task of semantic word retrieval (verbal fluency) in patients with multiple sclerosis (MS) and compare with the rCBF distribution of normal controls. Two groups of patients with low and high verbal fluency scores and two groups of normal controls were selected to determine a relationship between rCBF and verbal performance. A three-detector gamma camera (TRIAD 88) was used with radiotracer Tc-99m HMPAO and single photon emission computed tomography (SPECT) to obtain 3D rCBF maps. The performance characteristics of the camera was comprehensively studied before being utilized for clinical studies. In addition, technical improvements were implemented in the form of scatter correction and MRI-SPECT coregistration to potentially enhance the quantitative accuracy of the rCBF data. The performance analysis of the gamma camera showed remarkable consistency among the three-detector heads and yielded results that were consistent with the manufacturer's specification. Measurements of physical objects also showed excellent image quality. The coregistration of SPECT and MRI images allowed more accurate anatomical localization for extraction of regional blood flow information. The validation of the scatter correction technique with physical phantoms indicated marked improvements in quantitative accuracy. There was marked difference in activation patterns between patients and normals. In normals, individually subjects showed either an increase or a decrease in blood flow to left frontal and temporal, however, on average, there was not a statistically significant change. The lack of significant change may suggest large variability among subjects chosen or that the individual changes are not large enough to be significant. The results from MS patients showed several left cortical areas with statistically significant change in blood flow after cognitive activation

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.

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

Quality Assurance in Biobanking for Pre-Clinical Research

PubMed Central

Simeon-Dubach, Daniel; Zeisberger, Steffen M.; Hoerstrup, Simon P.

2016-01-01

It is estimated that not less than USD 28 billion are spent each year in the USA alone on irreproducible pre-clinical research, which is not only a fundamental loss of investment and resources but also a strong inhibitor of efficiency for upstream processes regarding the translation towards clinical applications and therapies. The issues and cost of irreproducibility has mainly been published on pre-clinical research. In contrast to pre-clinical research, test material is often being transferred into humans in clinical research. To protect treated human subjects and guarantee a defined quality standard in the field of clinical research, the manufacturing and processing infrastructures have to strictly follow and adhere to certain (inter-)national quality standards. It is assumed and suggested by the authors that by an implementation of certain quality standards within the area of pre-clinical research, billions of USD might be saved and the translation phase of promising pre-clinical results towards clinical applications may substantially be improved. In this review, we discuss how an implementation of a quality assurance (QA) management system might positively improve sample quality and sustainability within pre-clinically focused biobank infrastructures. Biobanks are frequently positioned at the very beginning of the biomedical research value chain, and, since almost every research material has been stored in a biobank during the investigated life cycle, biobanking seems to be of substantial importance from this perspective. The role model of a QA-regulated biobank structure can be found in biobanks within the context of clinical research organizations such as in regenerative medicine clusters. PMID:27781023

Cortical damage following traumatic brain injury evaluated by iomazenil SPECT and in vivo microdialysis.

PubMed

Koizumi, Hiroyasu; Fujisawa, Hirosuke; Suehiro, Eiichi; Iwanaga, Hideyuki; Nakagawara, Jyoji; Suzuki, Michiyasu

2013-01-01

[(123)I] iomazenil (IMZ) single photon emission computed tomography (SPECT) has been reported to be a useful marker of neuronal integrity. We evaluated cortical damage following traumatic brain injury (TBI) with IMZ SPECT at the acute stage. After conventional therapy for a cranial trauma, an IMZ SPECT re-evaluation was performed at the chronic stage. A reduction in IMZ uptake in the location of cerebral contusions was observed during the TBI acute phase; however, images of IMZ SPECT obtained during the chronic phase showed that areas with decreased IMZ distribution were remarkably reduced compared with those obtained during the acute phase. As a result of in vivo microdialysis study, the extracellular levels of glutamate in the cortex, where decreased IMZ distribution was shown during the acute phase, were increased during the 168-h monitoring period. During the chronic phase, IMZ uptake in the region with the microdialysis probes was recovered. The results suggest that this reduction in IMZ uptake might not be a sign of irreversible tissue damage in TBI.

Role of 99mTc-ECD SPECT in the Management of Children with Craniosynostosis

PubMed Central

Barik, Mayadhar; Bajpai, Minu; Das, Rashmi Ranajn; Malhotra, Arun; Panda, Shasanka Shekhar; Sahoo, Manas Kumar; Dwivedi, Sadanand

2014-01-01

Purpose of the Report. There is a paucity of data on correlation of various imaging modalities with clinical findings in craniosynostosis. Moreover, no study has specifically reported the role of 99mTc-ECD SPECT in a large number of subjects with craniosynostosis. Materials and Methods. We prospectively analyzed a cohort of 85 patients with craniosynostosis from year 2007 to 2012. All patients underwent evaluation with 99mTc-ECD SPECT and the results were correlated with radiological and surgical findings. Results. 99mTc-ECD SPECT revealed regional perfusion abnormalities in the cerebral hemisphere corresponding to the fused sutures preoperatively that disappeared postoperatively in all the cases. Corresponding to this, the mean mental performance quotient (MPQ) increased significantly (P < 0.05) postoperatively only in those children with absent perfusion defect postoperatively. Conclusions. Our study suggests that early surgery and release of craniosynostosis in patients with preoperative perfusion defects (absent on 99mTc-ECD SPECT study) are beneficial, as theylead to improved MPQ after surgery. PMID:24987670

Diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT: a clinical follow up study.

PubMed

Menéndez-González, Manuel; Tavares, Francisco; Zeidan, Nahla; Salas-Pacheco, José M; Arias-Carrión, Oscar

2014-01-01

The [(123)I]ioflupane-a dopamine transporter radioligand-SPECT (DaT-SPECT) has proven to be useful in the differential diagnosis of tremor. Here, we investigate the diagnoses behind patients with hard-to-classify tremor and normal DaT-SPECT. Therefore, 30 patients with tremor and normal DaT-SPECT were followed up for 2 years. In 18 cases we were able to make a diagnosis. The residual 12 patients underwent a second DaT-SPECT, were then followed for additional 12 months and thereafter the diagnosis was reconsidered again. The final diagnoses included cases of essential tremor, dystonic tremor, multisystem atrophy, vascular parkinsonism, progressive supranuclear palsy, corticobasal degeneration, fragile X-associated tremor ataxia syndrome, psychogenic parkinsonism, iatrogenic parkinsonism and Parkinson's disease. However, for 6 patients the diagnosis remained uncertain. Larger series are needed to better establish the relative frequency of the different conditions behind these cases.

Clinical Usefulness of SPECT-CT in Patients with an Unexplained Pain in Metal on Metal (MOM) Total Hip Arthroplasty.

PubMed

Berber, Reshid; Henckel, Johann; Khoo, Michael; Wan, Simon; Hua, Jia; Skinner, John; Hart, Alister

2015-04-01

SPECT-CT is increasingly used to assess painful knee arthroplasties. The aim of this study was to evaluate the clinical usefulness of SPECT-CT in unexplained painful MOM hip arthroplasty. We compared the diagnosis and management plan for 19 prosthetic MOM hips in 15 subjects with unexplained pain before and after SPECT-CT. SPECT-CT changed the management decision in 13 (68%) subjects, Chi-Square=5.49, P=0.24. In 6 subjects (32%) pain remained unexplained however the result reassured the surgeon to continue with non-operative management. SPECT-CT should be reserved as a specialist test to help identify possible causes of pain where conventional investigations have failed. It can help reassure surgeons making management decisions for patients with unexplained pain following MOM hip arthroplasty. Copyright © 2014 Elsevier Inc. All rights reserved.

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

Development of a Position Decoding ASIC for SPECT using Silicon Photomultiplier

NASA Astrophysics Data System (ADS)

Cho, M.; Kim, H.; Lim, K. T.; Cho, G.

2016-01-01

Single Photon Emission Computed Tomography(SPECT) is a widely used diagnosis modality for detecting metabolic diseases. In general, SPECT system is consisted of a sensor, a pre-amplifier, position decoding circuits(PDC) and a data acquisition(DAQ) system. Due to such complexity, it is quite costly to assemble SPECT system by putting discrete components together. Moreover, using discrete components would make the system rather bulky. In this work, we designed a channel module ASIC for SPECT system. This system was composed of a transimpedance amplifier(TIA), comparators and digital logics. In this particular module, a TIA was selected as a preamplifier because the decay time and the rise time are shorter than that of other preamplifier topologies. In the proposed module, the amplified pulse from the TIA was split into two separate signals and each signal was then fed into two comparators with different reference levels, e.g., a low and high level. Then an XOR gate combined the comparator outputs and the output of XOR gate was sent to the suceeding digital logic. Furthermore, the output of each component in the module is composed of a signal packet. The packet includes the information on the energy, the time and the position of the incident photon. The energy and position information of a detected radiation can be derived from the output of the D-flipflop(DFF) in the module via time-over-threshold(TOT). The timing information was measured using a delayed rising edge from the low-level referenced comparator. There are several advantages in developing the channel module ASIC. First of all, the ASIC has only digital outputs and thus a correction circuit for analog signal distortion can be neglected. In addition, it is possible to cut down the system production cost because the volume of the system can be reduced due to the compactness of ASIC. The benefits of channel module is not only limited to SPECT but also beneficial to many other radiation detecting systems.

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.

Preclinical electrogastrography in experimental pigs

PubMed Central

Květina, Jaroslav; Varayil, Jithinraj Edakkanambeth; Ali, Shahzad Marghoob; Kuneš, Martin; Bureš, Jan; Tachecí, Ilja; Rejchrt, Stanislav; Kopáčová, Marcela

2010-01-01

Surface electrogastrography (EGG) is a non-invasive means of recording gastric myoelectric activity or slow waves from cutaneous leads placed over the stomach. This paper provides a comprehensive review of preclinical EGG. Our group recently set up and worked out the methods for EGG in experimental pigs. We gained our initial experience in the use of EGG in assessment of porcine gastric myoelectric activity after volume challenge and after intragastric administration of itopride and erythromycin. The mean dominant frequency in pigs is comparable with that found in humans. EGG in experimental pigs is feasible. Experimental EGG is an important basis for further preclinical projects in pharmacology and toxicology. PMID:21217873

CAP—advancing the evaluation of preclinical Alzheimer disease treatments

PubMed Central

Reiman, Eric M.; Langbaum, Jessica B.; Tariot, Pierre N.; Lopera, Francisco; Bateman, Randall J.; Morris, John C.; Sperling, Reisa A.; Aisen, Paul S.; Roses, Allen D.; Welsh-Bohmer, Kathleen A.; Carrillo, Maria C.; Weninger, Stacie

2016-01-01

If we are to find treatments to postpone, reduce the risk of, or completely prevent the clinical onset of Alzheimer disease (AD), we need faster methods to evaluate promising preclinical AD treatments, new ways to work together in support of common goals, and a determination to expedite the initiation and performance of preclinical AD trials. In this article, we note some of the current challenges, opportunities and emerging strategies in preclinical AD treatment. We describe the Collaboration for Alzheimer’s Prevention (CAP)—a convening, harmonizing and consensus-building initiative to help stakeholders advance AD prevention research with rigour, care and maximal impact—and we demonstrate the impact of CAP on the goals and design of new preclinical AD trials. PMID:26416539

Molecular Imaging of Hydrolytic Enzymes Using PET and SPECT

PubMed Central

Rempel, Brian P.; Price, Eric W.

2017-01-01

Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health. However, the expression and/or activity of these important enzymes can change in many different diseases and therefore represent exciting targets for the development of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radiotracers. This review focuses on recently reported radiolabeled substrates, reversible inhibitors, and irreversible inhibitors investigated as PET and SPECT tracers for imaging hydrolytic enzymes. By learning from the most successful examples of tracer development for hydrolytic enzymes, it appears that an early focus on careful enzyme kinetics and cell-based studies are key factors for identifying potentially useful new molecular imaging agents. PMID:28927325

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.

Molecular Imaging of Hydrolytic Enzymes Using PET and SPECT.

PubMed

Rempel, Brian P; Price, Eric W; Phenix, Christopher P

2017-01-01

Hydrolytic enzymes are a large class of biological catalysts that play a vital role in a plethora of critical biochemical processes required to maintain human health. However, the expression and/or activity of these important enzymes can change in many different diseases and therefore represent exciting targets for the development of positron emission tomography (PET) and single-photon emission computed tomography (SPECT) radiotracers. This review focuses on recently reported radiolabeled substrates, reversible inhibitors, and irreversible inhibitors investigated as PET and SPECT tracers for imaging hydrolytic enzymes. By learning from the most successful examples of tracer development for hydrolytic enzymes, it appears that an early focus on careful enzyme kinetics and cell-based studies are key factors for identifying potentially useful new molecular imaging agents.

Database of normal human cerebral blood flow measured by SPECT: II. Quantification of I-123-IMP studies with ARG method and effects of partial volume correction.

PubMed

Inoue, Kentaro; Ito, Hiroshi; Shidahara, Miho; Goto, Ryoi; Kinomura, Shigeo; Sato, Kazunori; Taki, Yasuyuki; Okada, Ken; Kaneta, Tomohiro; Fukuda, Hiroshi

2006-02-01

The limited spatial resolution of SPECT causes a partial volume effect (PVE) and can lead to the significant underestimation of regional tracer concentration in the small structures surrounded by a low tracer concentration, such as the cortical gray matter of an atrophied brain. The aim of the present study was to determine, using 123I-IMP and SPECT, normal CBF of elderly subjects with and without PVE correction (PVC), and to determine regional differences in the effect of PVC and their association with the regional tissue fraction of the brain. Quantitative CBF SPECT using 123I-IMP was performed in 33 healthy elderly subjects (18 males, 15 females, 54-74 years old) using the autoradiographic method. We corrected CBF for PVE using segmented MR images, and analyzed quantitative CBF and regional differences in the effect of PVC using tissue fractions of gray matter (GM) and white matter (WM) in regions of interest (ROIs) placed on the cortical and subcortical GM regions and deep WM regions. The mean CBF in GM-ROIs were 31.7 +/- 6.6 and 41.0 +/- 8.1 ml/100 g/min for males and females, and in WM-ROIs, 18.2 +/- 0.7 and 22.9 +/- 0.8 ml/100 g/min for males and females, respectively. The mean CBF in GM-ROIs after PVC were 50.9 +/- 12.8 and 65.8 +/- 16.1 ml/100 g/min for males and females, respectively. There were statistically significant differences in the effect of PVC among ROIs, but not between genders. The effect of PVC was small in the cerebellum and parahippocampal gyrus, and it was large in the superior frontal gyrus, superior parietal lobule and precentral gyrus. Quantitative CBF in GM recovered significantly, but did not reach values as high as those obtained by invasive methods or in the H2(15)O PET study that used PVC. There were significant regional differences in the effect of PVC, which were considered to result from regional differences in GM tissue fraction, which is more reduced in the frontoparietal regions in the atrophied brain of the elderly.

Added Value of SPECT/CT in the Evaluation of Benign Bone Diseases of the Appendicular Skeleton.

PubMed

Abikhzer, Gad; Srour, Saher; Keidar, Zohar; Bar-Shalom, Rachel; Kagna, Olga; Israel, Ora; Militianu, Daniela

2016-04-01

Bone scintigraphy is a sensitive technique to detect altered bone mineralization but has limited specificity. The use of SPECT/CT has improved significantly the diagnostic accuracy of bone scintigraphy, in patients with cancer as well as in evaluation of benign bone disease. It provides precise localization and characterization of tracer-avid foci, shortens the diagnostic workup, and decreases patient anxiety. Through both the SPECT and the CT components, SPECT/CT has an incremental value in characterizing benign bone lesions, specifically in the appendicular skeleton, as illustrated by present case series.

[123I]beta-CIT SPECT visualizes dopamine transporter loss in de novo parkinsonian patients.

PubMed

Müller, T; Farahati, J; Kuhn, W; Eising, E G; Przuntek, H; Reiners, C; Coenen, H H

1998-01-01

Parkinson's disease (PD) is characterized by degeneration of dopaminergic neurons in the basal ganglia, which may be visualized by single photon emission computed tomography (SPECT) in combination with the cocaine analog methyl-3-beta-(4-beta[123I]iodophenyl)tropane-2beta-carboxylate ([123I]beta-CIT). The aim of our study was to correlate findings of SPECT with clinical data of 34 previously untreated, idiopathic parkinsonian patients [age: 59.58+/-10.03 (mean+/-SD) years; Hoehn and Yahr Scale (HYS) mean range: 1.97+/-0.83, ranges I-III; Unified PD Rating Scale 3.0 (UPDRS, 30.64+/-18.68) and 15 healthy controls (age 47.93+/-10.47 years). SPECT scans were performed with a single-head gamma-camera 24 h after intravenous injection of [123I]beta-CIT. Comparison of the striatum/cerebellum (S/C) ratio of [123I]beta-CIT uptake of controls and parkinsonian subjects, subdivided according to their HYS range, was significant. No influence of age or sex was observed. Significant correlations were found between scores of the HYS, UPDRS parts I-III, part II, part III, and the S/C ratio of [123I]-CIT uptake. Moreover, SPECT with the radiotracer [123I]beta-CIT revealed side-to-side differences in parkinsonian patients and significant associations to contralateral clinical extrapyramidal symptomatology. Our data show that SPECT with [123I]beta-CIT is a valuable tool for estimating disease severity in PD.

The early years of single photon emission computed tomography (SPECT): an anthology of selected reminiscences.

PubMed

Jaszczak, Ronald Jack

2006-07-07

The origin of SPECT can be found in pioneering experiments on emission tomography performed approximately 50 years ago. This historical review consists of a compilation of first person recollections from nine trailblazing scientists who shaped the early years of SPECT instrumentation during the 1960s and 1970s.

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.

Toward a practical template-based approach to semiquantitative SPECT myocardial perfusion imaging.

PubMed

Hughes, Tyler; Celler, Anna

2012-03-01

Our template-based quantitative perfusion single photon emission computed tomography (SPECT) method (T-QPS) performs semiquantitative analysis for myocardial perfusion imaging (MPI) without the use of normal databases. However, in its current form, T-QPS requires extensive calculations, which limits its clinical application. In the interest of clinical feasibility, the authors examine the trade-off between accuracy and processing time as the method is simplified. The T-QPS method uses the reconstructed SPECT image of the patient to create a 3D digital template of his∕her healthy heart. This template is then projected, reconstructed, and sampled into the bulls-eye map domain. A ratio of the patient and template images produces a final corrected image in which a threshold is applied to identify perfusion defects. In principle, the template should be constructed with the heart and all extracardiac activity, and the projection step should include primary and scatter components; however, this leads to lengthy calculations. In an attempt to shorten the processing time, the authors analyzed the performance of four template (T) generation methods: T(P-HRT), T(PS-HRT), T(P-HRTBKG), and T(PS-HRTBKG), where P and S represent primary and scattered photons included in the projection step, respectively; and HRT and HRTBKG represent template constructed with the heart only and the heart with background activity, respectively. Forty-eight thorax phantoms and 21 randomly selected patient studies were analyzed using each approach. All studies used GE's Infinia Hawkeye SPECT∕CT system and followed a standard cardiac acquisition protocol. Approximate processing times for the T(P-HRT), T(PS-HRT), T(P-HRTBKG), and T(PS-HRTBKG) methods were less than a minute, 2-3 h, less than a minute and 3-4 h, respectively. In both the simulation and patient studies, a significant reduction in the quality of perfusion defect definition was exhibited by the T(P-HRT) method relative to the other

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 importance of Tc-MAA SPECT/CT for therapy planning of radioembolization in a patient treated with bevacizumab.

PubMed

Ahmadzadehfar, Hojjat; Sabet, Amir; Meyer, Carsten; Habibi, Elham; Biersack, Hans-Jürgen; Ezziddin, Samer

2012-11-01

A 76-year-old man with colorectal cancer and hepatic metastases was referred to us for radioembolization of the liver. Angiography with 99mTc-MAA SPECT/CT was performed 8 weeks after the discontinuation of bevacizumab. 99mTc-MAA SPECT/CT showed a diffused intrahepatic tracer distribution with no focally accentuated accumulation in the tumorous region. The test was repeated 6 weeks later and Tc-MAA SPECT/CT showed this time a tumor accentuated tracer accumulation in the liver. Subsequently, the patient was treated with resin microspheres. Tc-MAA SPECT/CT allows a better evaluation of intrahepatic tracer accumulation of Tc-MAA and facilitates the determination of the most appropriate treatment time.

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.

Regional radiation dose-response modeling of functional liver in hepatocellular carcinoma patients with longitudinal sulfur colloid SPECT/CT: a proof of concept.

PubMed

Price, Ryan G; Apisarnthanarax, Smith; Schaub, Stephanie K; Nyflot, Matthew J; Chapman, Tobias R; Matesan, Manuela; Vesselle, Hubert J; Bowen, Stephen R

2018-06-19

We report on patient-specific quantitative changes in longitudinal sulfur colloid SPECT/CT as a function of regional radiation dose distributions to normal liver in a cohort of hepatocellular carcinoma patients. Dose-response thresholds and slopes varied with baseline liver function metrics, and extreme values were found in patients with fatal hepatotoxicity. Dose-response modeling of normal liver in individual HCC patients has potential to characterize in vivo radiosensitivity, identify high risk subgroups, and personalize treatment planning dose constraints. Hepatotoxicity risk in hepatocellular carcinoma (HCC) patients is modulated by radiation dose delivered to normal liver tissue, but reported dose-response data are limited. Our prior work established baseline [ 99m Tc]sulfur colloid (SC) SPECT/CT liver function imaging biomarkers that predict clinical outcomes. We conducted a proof-of-concept investigation with longitudinal SC SPECT/CT to characterize patient-specific radiation dose-response relationships as surrogates for liver radiosensitivity. SC SPECT/CT images of 15 HCC patients with variable Child-Pugh status (8 CP-A, 7 CP-B/C) were acquired in treatment position prior to and 1 month (nominal) after SBRT (n=6) or proton therapy (n=9). Localized rigid registrations between pre/post-treatment CT to planning CT scans were performed, and transformations were applied to pre/post-treatment SC SPECT images. Radiotherapy doses were converted to EQD2 α/β=3 and Gy (RBE), and binned in 5 GyEQD2 increments within tumor-subtracted livers. Mean dose and percent change (%ΔSC) between pre- and post-treatment SPECT uptake, normalized to regions receiving < 5 GyEQD2, were calculated in each binned dose region. Dose-response data were parameterized by sigmoid functions (double exponential) consisting of maximum reduction (%ΔSC max ), dose midpoint (D mid ), and dose-response slope (α mid ) parameters. Individual patient sigmoid dose-response curves had high goodness

Partition Model-Based 99mTc-MAA SPECT/CT Predictive Dosimetry Compared with 90Y TOF PET/CT Posttreatment Dosimetry in Radioembolization of Hepatocellular Carcinoma: A Quantitative Agreement Comparison.

PubMed

Gnesin, Silvano; Canetti, Laurent; Adib, Salim; Cherbuin, Nicolas; Silva Monteiro, Marina; Bize, Pierre; Denys, Alban; Prior, John O; Baechler, Sebastien; Boubaker, Ariane

2016-11-01

90 Y-microsphere selective internal radiation therapy (SIRT) is a valuable treatment in unresectable hepatocellular carcinoma (HCC). Partition-model predictive dosimetry relies on differential tumor-to-nontumor perfusion evaluated on pretreatment 99m Tc-macroaggregated albumin (MAA) SPECT/CT. The aim of this study was to evaluate agreement between the predictive dosimetry of 99m Tc-MAA SPECT/CT and posttreatment dosimetry based on 90 Y time-of-flight (TOF) PET/CT. We compared the 99m Tc-MAA SPECT/CT results for 27 treatment sessions (25 HCC patients, 41 tumors) with 90 Y SIRT (7 glass spheres, 20 resin spheres) and the posttreatment 90 Y TOF PET/CT results. Three-dimensional voxelized dose maps were computed from the 99m Tc-MAA SPECT/CT and 90 Y TOF PET/CT data. Mean absorbed dose ([Formula: see text]) was evaluated to compute the predicted-to-actual dose ratio ([Formula: see text]) in tumor volumes (TVs) and nontumor volumes (NTVs) for glass and resin spheres. The Lin concordance ([Formula: see text]) was used to measure accuracy ([Formula: see text]) and precision (ρ). Administered activity ranged from 0.8 to 1.9 GBq for glass spheres and from 0.6 to 3.4 GBq for resin spheres, and the respective TVs ranged from 2 to 125 mL and from 6 to 1,828 mL. The mean dose [Formula: see text] was 240 Gy for glass and 122 Gy for resin in TVs and 72 Gy for glass and 47 Gy for resin in NTVs. [Formula: see text] was 1.46 ± 0.58 (0.65-2.53) for glass and 1.16 ± 0.41 (0.54-2.54) for resin, and the respective values for [Formula: see text] were 0.88 ± 0.15 (0.56-1.00) and 0.86 ± 0.2 (0.58-1.35). DR variability was substantially lower in NTVs than in TVs. The Lin concordance between [Formula: see text] and [Formula: see text] (resin) was significantly better for tumors larger than 150 mL than for tumors 150 mL or smaller ([Formula: see text] = 0.93 and [Formula: see text] = 0.95 vs. [Formula: see text] = 0.57 and [Formula: see text] = 0.93; P < 0.05). In 90 Y radioembolization

Neuropsychiatric symptoms predict hypometabolism in preclinical Alzheimer disease.

PubMed

Ng, Kok Pin; Pascoal, Tharick A; Mathotaarachchi, Sulantha; Chung, Chang-Oh; Benedet, Andréa L; Shin, Monica; Kang, Min Su; Li, Xiaofeng; Ba, Maowen; Kandiah, Nagaendran; Rosa-Neto, Pedro; Gauthier, Serge

2017-05-09

To identify regional brain metabolic dysfunctions associated with neuropsychiatric symptoms (NPS) in preclinical Alzheimer disease (AD). We stratified 115 cognitively normal individuals into preclinical AD (both amyloid and tau pathologies present), asymptomatic at risk for AD (either amyloid or tau pathology present), or healthy controls (no amyloid or tau pathology present) using [ 18 F]florbetapir PET and CSF phosphorylated tau biomarkers. Regression and voxel-based regression models evaluated the relationships between baseline NPS measured by the Neuropsychiatric Inventory (NPI) and baseline and 2-year change in metabolism measured by [ 18 F]fluorodeoxyglucose (FDG) PET. Individuals with preclinical AD with higher NPI scores had higher [ 18 F]FDG uptake in the posterior cingulate cortex (PCC), ventromedial prefrontal cortex, and right anterior insula at baseline. High NPI scores predicted subsequent hypometabolism in the PCC over 2 years only in individuals with preclinical AD. Sleep/nighttime behavior disorders and irritability and lability were the components of the NPI that drove this metabolic dysfunction. The magnitude of NPS in preclinical cases, driven by sleep behavior and irritability domains, is linked to transitory metabolic dysfunctions within limbic networks vulnerable to the AD process and predicts subsequent PCC hypometabolism. These findings support an emerging conceptual framework in which NPS constitute an early clinical manifestation of AD pathophysiology. Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Nephron segment specific microRNA biomarkers of pre-clinical drug-induced renal toxicity: Opportunities and challenges

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

Nassirpour, Rounak, E-mail: Rounak.nassirpour@pfiz

Drug-induced nephrotoxicity is a common drug development complication for pharmaceutical companies. Sensitive, specific, translatable and non-invasive biomarkers of renal toxicity are urgently needed to diagnose nephron segment specific injury. The currently available gold standard biomarkers for nephrotoxicity are not kidney-specific, lack sensitivity for early detection, and are not suitable for renal damage localization (glomerular vs tubulointerstitial injury). MicroRNAs (miRNAs) are increasingly gaining momentum as promising biomarkers of various organ toxicities, including drug induced renal injury. This is mostly due to their stability in easily accessible biofluids, ease of developing nucleic acids detection compared to protein detection assays, as well asmore » their interspecies translatability. Increasing concordance of miRNA findings by standardizing methodology most suitable for their detection and quantitation, as well as characterization of their expression pattern in a cell type specific manner, will accelerate progress toward validation of these miRNAs as biomarkers in pre-clinical, and clinical settings. This review aims to highlight the current pre-clinical findings surrounding miRNAs as biomarkers in two important segments of the nephron, the glomerulus and tubules. - Highlights: • miRNAs are promising biomarkers of drug-induced kidney injury. • Summarized pre-clinical miRNA biomarkers of drug-induced nephrotoxicity. • Described the strengths and challenges associated with miRNAs as biomarkers.« 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

Review of two years of experiences with SPECT among psychiatric patients in a rural hospital setting.

PubMed

Sheehan, William; Thurber, Steven

2008-09-01

We summarize single proton emission computed tomography (SPECT) findings from 63 psychiatric patients in a small rural hospital in western Minnesota. SPECT scans were ordered only for patients in whom documentation of hypoperfusion and functional deficits might be helpful in clarifying diagnoses and treatment planning. The patients referred for SPECT scans had histories of traumatic brain injuries, atypical psychiatric symptom presentations, or conditions that were refractory to standard treatments. In the context of strict referral guidelines and close psychiatrist-radiologist collaboration, a much higher yield of significant findings was obtained compared with those noted in other reports in the literature.

A new scalable modular data acquisition system for SPECT (PET)

NASA Astrophysics Data System (ADS)

Stenstrom, P.; Rillbert, A.; Bergquist, M.; Habte, F.; Bohm, C.; Larsson, S. A.

1998-06-01

Describes a modular decentralized data acquisition system that continuously samples shaped PMT pulses from a SPECT detector. The pulse waveform data are used by signal processors to accurately reconstruct amplitude and time for each scintillation event. Data acquisition for a PMT channel is triggered in two alternative ways, either when its own signal exceeds a selected digital threshold, or when it receives a trigger pulse from one of its neighboring PMTs. The triggered region is restricted to seven, thirteen or nineteen neighboring PMT channels. Each acquisition module supports three PMT channels and connects to all other modules and a reconstruction computer via Firewire to cover the 72 channels in the Stockholm University/Karolinska Hospital cylindrical SPECT camera.

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

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.

Early and delayed pinhole MIBI SPECT in detecting hyperfunctioning parathyroid glands: a comparison with peroperative γ probe.

PubMed

Gültekin, Salih Sinan; Kir, Metin; Tuğ, Tuğbay; Demirer, Seher; Genç, Yasemin

2011-10-01

This study was conducted to evaluate the early and delayed pinhole MIBI single photon emission computed tomography (pSPECT) images in detecting hyperfunctioning parathyroid glands, to make a comparison with peroperative γ probe (GP) findings. Planar, early, and delayed pSPECT scans and skin in-vivo and ex-vivo GP counts were obtained in 22 patients with hyperparathyroidism. All data were analyzed statistically on the basis of localization of the lesions, using the histopathological findings as the gold standard. Histopathological examinations revealed 18 of 44 adenomas, 18 of 44 hyperplasic glands, two of 44 lymph nodules, five of 44 thyroid nodules, and one of 44 normal parathyroid glands. Sensitivity and specificity were found to be 36 and 100% for planar, 69 and 75% for early pSPECT, 86 and 88% for delayed pSPECT scans, and similarly, 78 and 75% on skin, 92 and 75% in-vivo and 83 and 100% ex-vivo GP counts, respectively. For distinction ability of GP counts between three groups of lesions, there was a statistically significant difference among the three groups for ex-vivo GP counts but not between groups of adenomas and hyperplasic lesions for in-vivo GP counts. Early and delayed pSPECT scans play a complementary role on the planar scans. Delayed pSPECT scans and in-vivo GP counts are equally valuable to localize both single and multiple hyperfunctioning parathyroid glands. Ex-vivo GP counts seem to be better for making a distinction among types of lesions.

99m Tc-MIP-1404-SPECT/CT for the detection of PSMA-positive lesions in 225 patients with biochemical recurrence of prostate cancer.

PubMed

Schmidkonz, Christian; Hollweg, Claudia; Beck, Michael; Reinfelder, Julia; Goetz, Theresa I; Sanders, James C; Schmidt, Daniela; Prante, Olaf; Bäuerle, Tobias; Cavallaro, Alexander; Uder, Michael; Wullich, Bernd; Goebell, Peter; Kuwert, Torsten; Ritt, Philipp

2018-01-01

99m Tc-MIP-1404 (Progenics Pharmaceuticals, Inc., New York, NY) is a novel, SPECT-compatible 99m Tc-labeled PSMA inhibitor for the detection of prostate cancer. We present results of its clinical use in a cohort of 225 men with histologically confirmed prostate cancer referred for workup of biochemical relapse. From April 2013 to April 2017, 99m Tc-MIP1404-scintigraphy was performed in 225 patients for workup of PSA biochemical relapse of prostate cancer. Whole-body planar and SPECT/CT images of the lower abdomen and thorax were obtained 3-4 h p.i. of 710 ± 64 MBq 99m Tc-MIP-1404. Images were visually analyzed for presence and location of abnormal uptake. In addition, quantitative analysis of the SPECT/CT data was carried out on a subset of 125 patients. Follow-up reports of subsequent therapeutic interventions were available for 59% (139) of all patients. Tracer-positive lesions were detected in 77% (174/225) of all patients. Detections occurred at the area of local recurrence in the prostate in 25% of patients (or a total of 56), with metastases in lymph nodes in 47% (105), bone in 27% (60), lung in 5% (12), and other locations in 2% (4) of patients. Detection rates were 90% at PSA levels ≥2 ng/mL and 54% below that threshold. Lesional SUVmax values were, on average, 32.2 ± 29.6 (0.8-142.2), and tumor-to-normal ratios 146.6 ± 160.5 (1.9-1482.4). The PSA level correlated significantly with total uptake of MIP-1404 in tumors (P < 0.001). Furthermore, total tumor uptake was significantly higher in patients with Gleason scores ≥8 compared to those with Gleason scores ≤7 (P < 0.05). In patients with androgen deprivation therapy, the detection rate was significantly higher compared to patients without androgen deprivation therapy (86% vs 71%, P < 0.001). Based on 99m Tc-MIP-1404-imaging and other information, an interdisciplinary tumor board review recommended changes to treatment plans in 74% (104/139) of those patients for whom

Determination of exposure multiples of human metabolites for MIST assessment in preclinical safety species without using reference standards or radiolabeled compounds.

PubMed

Ma, Shuguang; Li, Zhiling; Lee, Keun-Joong; Chowdhury, Swapan K

2010-12-20

A simple, reliable, and accurate method was developed for quantitative assessment of metabolite coverage in preclinical safety species by mixing equal volumes of human plasma with blank plasma of animal species and vice versa followed by an analysis using high-resolution full-scan accurate mass spectrometry. This approach provided comparable results (within (±15%) to those obtained from regulated bioanalysis and did not require synthetic standards or radiolabeled compounds. In addition, both qualitative and quantitative data were obtained from a single LC-MS analysis on all metabolites and, therefore, the coverage of any metabolite of interest can be obtained.

MO-DE-303-03: Session on quantitative imaging for assessment of tumor response to radiation therapy

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

Bowen, S.

This session will focus on quantitative imaging for assessment of tumor response to radiation therapy. This is a technically challenging method to translate to practice in radiation therapy. In the new era of precision medicine, however, delivering the right treatment, to the right patient, and at the right time, can positively impact treatment choices and patient outcomes. Quantitative imaging provides the spatial sensitivity required by radiation therapy for precision medicine that is not available by other means. In this Joint ESTRO -AAPM Symposium, three leading-edge investigators will present specific motivations for quantitative imaging biomarkers in radiation therapy of esophageal, headmore » and neck, locally advanced non-small cell lung cancer, and hepatocellular carcinoma. Experiences with the use of dynamic contrast enhanced (DCE) MRI, diffusion- weighted (DW) MRI, PET/CT, and SPECT/CT will be presented. Issues covered will include: response prediction, dose-painting, timing between therapy and imaging, within-therapy biomarkers, confounding effects, normal tissue sparing, dose-response modeling, and association with clinical biomarkers and outcomes. Current information will be presented from investigational studies and clinical practice. Learning Objectives: Learn motivations for the use of quantitative imaging biomarkers for assessment of response to radiation therapy Review the potential areas of application in cancer therapy Examine the challenges for translation, including imaging confounds and paucity of evidence to date Compare exemplary examples of the current state of the art in DCE-MRI, DW-MRI, PET/CT and SPECT/CT imaging for assessment of response to radiation therapy Van der Heide: Research grants from the Dutch Cancer Society and the European Union (FP7) Bowen: RSNA Scholar grant.« less

[Topodiagnosis of Creutzfeldt-Jakob disease using HMPAO-SPECT].

PubMed

Heye, N; Farahati, J; Heinz, A; Büttner, T; Przuntek, H; Reiners, C

1993-02-01

An 80-year old female presented with early stage Creutzfeldt-Jakob disease with clinical, neurophysiological and neuropathological findings suggesting a focal involvement of the brain. HMPAO SPECT disclosed asymmetries of regional cerebral perfusion, thus suggesting that it may be a further diagnostic instrument in this disease.

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.

Comparison of FDG-PET with MIBI-SPECT in the detection of breast cancer and axillary lymph node metastasis.

PubMed

Yutani, K; Shiba, E; Kusuoka, H; Tatsumi, M; Uehara, T; Taguchi, T; Takai, S I; Nishimura, T

2000-01-01

The purpose of this work was to compare [18F]2-deoxy-2-fluoro-D-glucose (FDG) PET and 99mTc-methoxyisobutylisonitrile (MIBI) SPECT in the detection of breast cancer and axillary lymph node metastasis in the same patients. FDG-PET and MIBI-SPECT were performed within 3 days for 40 women (age range 25-86 years old) with suspected breast cancer, in whom biopsies and/or mastectomies were performed. Both images were visually assessed, and the count ratio between tumor and normal tissue (T/N ratio) was calculated. Thirty-eight patients had breast cancer, and the remaining two had benign breast lesions. The sensitivities of FDG-PET and MIBI-SPECT were 78.9 and 76.3% for breast cancer and 50.0 and 37.5% for axillary lymph node metastasis, respectively. The T/N ratio of breast cancer was significantly higher in FDG-PET (6.01 +/- 3.08 mean +/- SD) than that in MIBI-SPECT (3.48 +/- 1.21) (p = 0.01). Nonmalignant diffuse uptake of FDG in the breasts and the accumulation of MIBI in heart and liver occasionally obscured tumor uptake. These results indicate that MIBI-SPECT is comparable with FDG-PET in detecting breast cancer. Neither FDG-PET nor MIBI-SPECT is sufficiently sensitive to rule out axillary lymph node metastasis.

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.

REVIEW: The early years of single photon emission computed tomography (SPECT): an anthology of selected reminiscences

NASA Astrophysics Data System (ADS)

Jaszczak, Ronald Jack

2006-07-01

The origin of SPECT can be found in pioneering experiments on emission tomography performed approximately 50 years ago. This historical review consists of a compilation of first person recollections from nine trailblazing scientists who shaped the early years of SPECT instrumentation during the 1960s and 1970s.

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.

Simultaneous CT and SPECT tomography using CZT detectors

DOEpatents

Paulus, Michael J.; Sari-Sarraf, Hamed; Simpson, Michael L.; Britton, Jr., Charles L.

2002-01-01

A method for simultaneous transmission x-ray computed tomography (CT) and single photon emission tomography (SPECT) comprises the steps of: injecting a subject with a tracer compound tagged with a .gamma.-ray emitting nuclide; directing an x-ray source toward the subject; rotating the x-ray source around the subject; emitting x-rays during the rotating step; rotating a cadmium zinc telluride (CZT) two-sided detector on an opposite side of the subject from the source; simultaneously detecting the position and energy of each pulsed x-ray and each emitted .gamma.-ray captured by the CZT detector; recording data for each position and each energy of each the captured x-ray and .gamma.-ray; and, creating CT and SPECT images from the recorded data. The transmitted energy levels of the x-rays lower are biased lower than energy levels of the .gamma.-rays. The x-ray source is operated in a continuous mode. The method can be implemented at ambient temperatures.

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

Compton camera study for high efficiency SPECT and benchmark with Anger system

NASA Astrophysics Data System (ADS)

Fontana, M.; Dauvergne, D.; Létang, J. M.; Ley, J.-L.; Testa, É.

2017-12-01

Single photon emission computed tomography (SPECT) is at present one of the major techniques for non-invasive diagnostics in nuclear medicine. The clinical routine is mostly based on collimated cameras, originally proposed by Hal Anger. Due to the presence of mechanical collimation, detection efficiency and energy acceptance are limited and fixed by the system’s geometrical features. In order to overcome these limitations, the application of Compton cameras for SPECT has been investigated for several years. In this study we compare a commercial SPECT-Anger device, the General Electric HealthCare Infinia system with a High Energy General Purpose (HEGP) collimator, and the Compton camera prototype under development by the French collaboration CLaRyS, through Monte Carlo simulations (GATE—GEANT4 Application for Tomographic Emission—version 7.1 and GEANT4 version 9.6, respectively). Given the possible introduction of new radio-emitters at higher energies intrinsically allowed by the Compton camera detection principle, the two detectors are exposed to point-like sources at increasing primary gamma energies, from actual isotopes already suggested for nuclear medicine applications. The Compton camera prototype is first characterized for SPECT application by studying the main parameters affecting its imaging performance: detector energy resolution and random coincidence rate. The two detector performances are then compared in terms of radial event distribution, detection efficiency and final image, obtained by gamma transmission analysis for the Anger system, and with an iterative List Mode-Maximum Likelihood Expectation Maximization (LM-MLEM) algorithm for the Compton reconstruction. The results show for the Compton camera a detection efficiency increased by a factor larger than an order of magnitude with respect to the Anger camera, associated with an enhanced spatial resolution for energies beyond 500 keV. We discuss the advantages of Compton camera application

Usefulness of coronary calcium scoring to myocardial perfusion SPECT in the diagnosis of coronary artery disease in a predominantly high risk population.

PubMed

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

2013-03-01

Coronary calcium scoring (CCS) adds to the diagnostic performance of myocardial perfusion single-photon emission computed tomography (SPECT) to assess the presence of significant coronary artery disease (CAD). Patients with a high pre-test likelihood are expected to have a high CCS which potentially could enhance the diagnostic performance of myocardial perfusion SPECT in this specific patient group. We evaluated the added value of CCS to SPECT in the diagnosis of significant CAD in patients with an intermediate to high pre-test likelihood. In total, 129 patients (mean age 62.7 ± 9.7 years, 65 % male) with stable anginal complaints and intermediate to high pre-test likelihood of CAD (median 87 %, range 22-95) were prospectively included in this study. All patients received SPECT and CCS imaging preceding invasive coronary angiography (CA). Fractional flow reserve (FFR) measurements were acquired from patients with angiographically estimated 50-95 % obstructive CAD. For SPECT a SSS > 3 was defined significant CAD. For CCS the optimal cut-off value for significant CAD was determined by ROC curve analysis. The reference standard for significant CAD was a FFR of <0.80 acquired by CA. Significant CAD was demonstrated in 64 patients (49.6 %). Optimal CCS cut-off value for significant CAD was >182.5. ROC curve analysis for prediction of the presence of significant CAD for SPECT, CCS and the combination of CCS and SPECT resulted in an area under the curve (AUC) of 0.88 (95 % CI 81-94), 0.75 (95 % CI 66-83 %) and 0.92 (95 % CI 87-97 %) respectively. The difference of the AUC between SPECT and the combination of CCS and SPECT was 0.05 (P = 0.12). The addition of CCS did not significantly improve the diagnostic performance of SPECT in the evaluation of patients with a predominantly high pre-test likelihood of CAD.

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.

A standardized method for the construction of tracer specific PET and SPECT rat brain templates: validation and implementation of a toolbox.

PubMed

Vállez Garcia, David; Casteels, Cindy; Schwarz, Adam J; Dierckx, Rudi A J O; Koole, Michel; Doorduin, Janine

2015-01-01

High-resolution anatomical image data in preclinical brain PET and SPECT studies is often not available, and inter-modality spatial normalization to an MRI brain template is frequently performed. However, this procedure can be challenging for tracers where substantial anatomical structures present limited tracer uptake. Therefore, we constructed and validated strain- and tracer-specific rat brain templates in Paxinos space to allow intra-modal registration. PET [18F]FDG, [11C]flumazenil, [11C]MeDAS, [11C]PK11195 and [11C]raclopride, and SPECT [99mTc]HMPAO brain scans were acquired from healthy male rats. Tracer-specific templates were constructed by averaging the scans, and by spatial normalization to a widely used MRI-based template. The added value of tracer-specific templates was evaluated by quantification of the residual error between original and realigned voxels after random misalignments of the data set. Additionally, the impact of strain differences, disease uptake patterns (focal and diffuse lesion), and the effect of image and template size on the registration errors were explored. Mean registration errors were 0.70 ± 0.32 mm for [18F]FDG (n = 25), 0.23 ± 0.10mm for [11C]flumazenil (n = 13), 0.88 ± 0.20 mm for [11C]MeDAS (n = 15), 0.64 ± 0.28 mm for [11C]PK11195 (n = 19), 0.34 ± 0.15 mm for [11C]raclopride (n = 6), and 0.40 ± 0.13 mm for [99mTc]HMPAO (n = 15). These values were smallest with tracer-specific templates, when compared to the use of [18F]FDG as reference template (p<0.001). Additionally, registration errors were smallest with strain-specific templates (p<0.05), and when images and templates had the same size (p ≤ 0.001). Moreover, highest registration errors were found for the focal lesion group (p<0.005) and the diffuse lesion group (p = n.s.). In the voxel-based analysis, the reported coordinates of the focal lesion model are consistent with the stereotaxic injection procedure. The use of PET/SPECT strain- and tracer

A Standardized Method for the Construction of Tracer Specific PET and SPECT Rat Brain Templates: Validation and Implementation of a Toolbox

PubMed Central

Vállez Garcia, David; Casteels, Cindy; Schwarz, Adam J.; Dierckx, Rudi A. J. O.; Koole, Michel; Doorduin, Janine

2015-01-01

High-resolution anatomical image data in preclinical brain PET and SPECT studies is often not available, and inter-modality spatial normalization to an MRI brain template is frequently performed. However, this procedure can be challenging for tracers where substantial anatomical structures present limited tracer uptake. Therefore, we constructed and validated strain- and tracer-specific rat brain templates in Paxinos space to allow intra-modal registration. PET [18F]FDG, [11C]flumazenil, [11C]MeDAS, [11C]PK11195 and [11C]raclopride, and SPECT [99mTc]HMPAO brain scans were acquired from healthy male rats. Tracer-specific templates were constructed by averaging the scans, and by spatial normalization to a widely used MRI-based template. The added value of tracer-specific templates was evaluated by quantification of the residual error between original and realigned voxels after random misalignments of the data set. Additionally, the impact of strain differences, disease uptake patterns (focal and diffuse lesion), and the effect of image and template size on the registration errors were explored. Mean registration errors were 0.70±0.32mm for [18F]FDG (n = 25), 0.23±0.10mm for [11C]flumazenil (n = 13), 0.88±0.20 mm for [11C]MeDAS (n = 15), 0.64±0.28mm for [11C]PK11195 (n = 19), 0.34±0.15mm for [11C]raclopride (n = 6), and 0.40±0.13mm for [99mTc]HMPAO (n = 15). These values were smallest with tracer-specific templates, when compared to the use of [18F]FDG as reference template (p&0.001). Additionally, registration errors were smallest with strain-specific templates (p&0.05), and when images and templates had the same size (p≤0.001). Moreover, highest registration errors were found for the focal lesion group (p&0.005) and the diffuse lesion group (p = n.s.). In the voxel-based analysis, the reported coordinates of the focal lesion model are consistent with the stereotaxic injection procedure. The use of PET/SPECT strain- and tracer-specific templates allows

NCI Pediatric Preclinical Testing Consortium

Cancer.gov

NCI has awarded grants to five research teams to participate in its Pediatric Preclinical Testing Consortium, which is intended to help to prioritize which agents to pursue in pediatric clinical trials.

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

Saccharin Aza Bioisosteres-Synthesis and Preclinical Property Comparisons.

PubMed

Chen, Yantao; Aurell, Carl-Johan; Pettersen, Anna; Lewis, Richard J; Hayes, Martin A; Lepistö, Matti; Jonson, Anna C; Leek, Hanna; Thunberg, Linda

2017-06-08

Saccharin is a well-known scaffold in drug discovery. Herein, we report the synthesis and preclinical property comparisons of three bioisosteres of saccharin: aza-pseudosaccharins (cluster B ), and two new types of aza-saccharins (clusters C and D ). We demonstrate a convenient protocol to selectively synthesize products in cluster C or D when primary amines are used. Preclinical characterization of selected matched-pair products is reported. Through comparison of two diastereomers, we highlight how stereochemistry affects the preclinical properties. Given that saccharin-based derivatives are widely used in many chemistry fields, we foresee that structures exemplified by clusters C and D offer new opportunities for novel drug design, creating a chiral center on the sulfur atom and the option of substitution at two different nitrogens.

The effect of heart motion on parameter bias in dynamic cardiac SPECT

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

Ross, S.G.; Gullberg, G.T.; Huesman, R.H.

1996-12-31

Dynamic cardiac SPECT can be used to estimate kinetic rate parameters which describe the wash-in and wash-out of tracer activity between the blood and the myocardial tissue. These kinetic parameters can in turn be correlated to myocardial perfusion. There are, however, many physical aspects associated with dynamic SPECT which can introduce errors into the estimates. This paper describes a study which investigates the effect of heart motion on kinetic parameter estimates. Dynamic SPECT simulations are performed using a beating version of the MCAT phantom. The results demonstrate that cardiac motion has a significant effect on the blood, tissue, and backgroundmore » content of regions of interest. This in turn affects estimates of wash-in, while it has very little effect on estimates of wash-out. The effect of cardiac motion on parameter estimates appears not to be as great as effects introduced by photon noise and geometric collimator response. It is also shown that cardiac motion results in little extravascular contamination of the left ventricle blood region of interest.« less

Hybrid Parallel-Slant Hole Collimators for SPECT Imaging

NASA Astrophysics Data System (ADS)

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

2004-06-01

We propose a new collimator geometry, the hybrid parallel-slant (HPS) hole geometry, to improve sensitivity for SPECT imaging with large field of view (LFOV) gamma cameras. A HPS collimator has one segment with parallel holes and one or more segments with slant holes. The collimator can be mounted on a conventional SPECT LFOV system that uses parallel-beam collimators, and no additional detector or collimator motion is required for data acquisition. The parallel segment of the collimator allows for the acquisition of a complete data set of the organs-of-interest and the slant segments provide additional data. In this work, simulation studies of an MCAT phantom were performed with a HPS collimator with one slant segment. The slant direction points from patient head to patient feet with a slant angle of 30/spl deg/. We simulated 64 projection views over 180/spl deg/ with the modeling of nonuniform attenuation effect, and then reconstructed images using an MLEM algorithm that incorporated the hybrid geometry. It was shown that sensitivity to the cardiac region of the phantom was increased by approximately 50% when using the HPS collimator compared with a parallel-hole collimator. No visible artifacts were observed in the myocardium and the signal-to-noise ratio (SNR) of the myocardium walls was improved. Compared with collimators with other geometries, using a HPS collimator has the following advantages: (a) significant sensitivity increase; (b) a complete data set obtained from the parallel segment that allows for artifact-free image reconstruction; and (c) no additional collimator or detector motion. This work demonstrates the potential value of hybrid geometry in collimator design for LFOV SPECT imaging.

[Follow-up of patients with good exercise capacity in stress test with myocardial single-photon emission computed tomography (SPECT)].

PubMed

González, Javiera; Prat, Hernán; Swett, Eduardo; Berrocal, Isabel; Fernández, René; Zhindon, Juan Pablo; Castro, Ariel; Massardo, Teresa

2015-11-01

The evaluation of coronary artery disease (CAD) can be performed with stress test and myocardial SPECT tomography. To assess the predictive value of myocardial SPECT using stress test for cardiovascular events in patients with good exercise capacity. We included 102 males aged 56 ± 10 years and 19 females aged 52 ± 10 years, all able to achieve 10 METs and ≥ 85% of the theoretical maximum heart rate and at least 8 min in their stress test with gated 99mTc-sestamibi SPECT. Eighty two percent of patients were followed clinically for 33 ± 17 months. Sixty seven percent of patients were studied for CAD screening and the rest for known disease assessment. Treadmill stress test was negative in 75.4%; 37% of patients with moderate to severe Duke Score presented ischemia. Normal myocardial perfusion SPECT was observed in 70.2%. Reversible defects appeared in 24.8% of cases, which were of moderate or severe degree (> 10% left ventricular extension) in 56.6%. Only seven cases had coronary events after the SPECT. Two major (myocardial infarction and emergency coronary revascularization) and 5 minor events (elective revascularization) ere observed in the follow-up. In a multivariate analysis, SPECT ischemia was the only statistically significant parameter that increased the probability of having a major or minor event. Nearly a quarter of our patients with good exercise capacity demonstrated reversible defects in their myocardial perfusion SPECT. In the intermediate-term follow-up, a low rate of cardiac events was observed, being the isotopic ischemia the only significant predictive parameter.

The influence of gravity on regional lung blood flow in humans: SPECT in the upright and head-down posture.

PubMed

Ax, M; Sanchez-Crespo, A; Lindahl, S G E; Mure, M; Petersson, J

2017-06-01

Previous studies in humans have shown that gravity has little influence on the distribution of lung blood flow while changing posture from supine to prone. This study aimed to evaluate the maximal influence of posture by comparison of regional lung blood flow in the upright and head-down posture in 8 healthy volunteers, using a tilt table. Regional lung blood flow was marked by intravenous injection of macroaggregates of human albumin labeled with 99m Tc or 113m In, in the upright and head-down posture, respectively, during tidal breathing. Both radiotracers remain fixed in the lung after administration. The distribution of radioactivity was mapped using quantitative single photon emission computed tomography (SPECT) corrected for attenuation and scatter. All images were obtained supine during tidal breathing. A shift from upright to the head-down posture caused a clear redistribution of blood flow from basal to apical regions. We conclude that posture plays a role for the distribution of lung blood flow in upright humans, and that the influence of posture, and thereby gravity, is much greater in the upright and head-down posture than in horizontal postures. However, the results of the study demonstrate that lung structure is the main determinant of regional blood flow and gravity is a secondary contributor to the distribution of lung blood flow in the upright and head-down positions. NEW & NOTEWORTHY Using a dual-isotope quantitative SPECT method, we demonstrated that although a shift in posture redistributes blood flow in the direction of gravity, the results are also consistent with lung structure being a greater determinant of regional blood flow than gravity. To our knowledge, this is the first study to use modern imaging methods to quantify the shift in regional lung blood flow in humans at a change between the upright and head-down postures. Copyright © 2017 the American Physiological Society.

A line-source method for aligning on-board and other pinhole SPECT systems

PubMed Central

Yan, Susu; Bowsher, James; Yin, Fang-Fang

2013-01-01

Purpose: In order to achieve functional and molecular imaging as patients are in position for radiation therapy, a robotic multipinhole SPECT system is being developed. Alignment of the SPECT system—to the linear accelerator (LINAC) coordinate frame and to the coordinate frames of other on-board imaging systems such as cone-beam CT (CBCT)—is essential for target localization and image reconstruction. An alignment method that utilizes line sources and one pinhole projection is proposed and investigated to achieve this goal. Potentially, this method could also be applied to the calibration of the other pinhole SPECT systems. Methods: An alignment model consisting of multiple alignment parameters was developed which maps line sources in three-dimensional (3D) space to their two-dimensional (2D) projections on the SPECT detector. In a computer-simulation study, 3D coordinates of line-sources were defined in a reference room coordinate frame, such as the LINAC coordinate frame. Corresponding 2D line-source projections were generated by computer simulation that included SPECT blurring and noise effects. The Radon transform was utilized to detect angles (α) and offsets (ρ) of the line-source projections. Alignment parameters were then estimated by a nonlinear least squares method, based on the α and ρ values and the alignment model. Alignment performance was evaluated as a function of number of line sources, Radon transform accuracy, finite line-source width, intrinsic camera resolution, Poisson noise, and acquisition geometry. Experimental evaluations were performed using a physical line-source phantom and a pinhole-collimated gamma camera attached to a robot. Results: In computer-simulation studies, when there was no error in determining angles (α) and offsets (ρ) of the measured projections, six alignment parameters (three translational and three rotational) were estimated perfectly using three line sources. When angles (α) and offsets (ρ) were provided by

A line-source method for aligning on-board and other pinhole SPECT systems.

PubMed

Yan, Susu; Bowsher, James; Yin, Fang-Fang

2013-12-01

In order to achieve functional and molecular imaging as patients are in position for radiation therapy, a robotic multipinhole SPECT system is being developed. Alignment of the SPECT system-to the linear accelerator (LINAC) coordinate frame and to the coordinate frames of other on-board imaging systems such as cone-beam CT (CBCT)-is essential for target localization and image reconstruction. An alignment method that utilizes line sources and one pinhole projection is proposed and investigated to achieve this goal. Potentially, this method could also be applied to the calibration of the other pinhole SPECT systems. An alignment model consisting of multiple alignment parameters was developed which maps line sources in three-dimensional (3D) space to their two-dimensional (2D) projections on the SPECT detector. In a computer-simulation study, 3D coordinates of line-sources were defined in a reference room coordinate frame, such as the LINAC coordinate frame. Corresponding 2D line-source projections were generated by computer simulation that included SPECT blurring and noise effects. The Radon transform was utilized to detect angles (α) and offsets (ρ) of the line-source projections. Alignment parameters were then estimated by a nonlinear least squares method, based on the α and ρ values and the alignment model. Alignment performance was evaluated as a function of number of line sources, Radon transform accuracy, finite line-source width, intrinsic camera resolution, Poisson noise, and acquisition geometry. Experimental evaluations were performed using a physical line-source phantom and a pinhole-collimated gamma camera attached to a robot. In computer-simulation studies, when there was no error in determining angles (α) and offsets (ρ) of the measured projections, six alignment parameters (three translational and three rotational) were estimated perfectly using three line sources. When angles (α) and offsets (ρ) were provided by the Radon transform, estimation

Value of gated SPECT in the analysis of regional wall motion of the interventricular septum after coronary artery bypass grafting.

PubMed

Giubbini, Raffaele; Rossini, Pierluigi; Bertagna, Francesco; Bosio, Giovanni; Paghera, Barbara; Pizzocaro, Claudio; Canclini, Silvana; Terzi, Arturo; Germano, Guido

2004-10-01

The aim of this study was the evaluation of septal wall motion, perfusion and wall thickening after CABG in two groups of consecutive patients, one with grafted left anterior coronary artery and no history of myocardial infarction, and the other with previous anteroseptal myocardial infarction and impaired septal motion before surgery. The issue addressed was the ability of gated SPECT to differentiate between true paradoxical septal motion, characterised by paradoxical wall motion, depressed ejection fraction (EF), poor viability and compromised wall thickening, and pseudo-paradoxical motion, characterised by abnormal wall motion and regional EF but preserved perfusion and wall thickening. One hundred and thirty-two patients with previous anterior myocardial infarction, 82 patients with left anterior descending coronary disease and no history of myocardial infarction and 27 normal subjects underwent rest gated SPECT after 99mTc-sestamibi injection, according to the standard QGS protocol. Quantitative regional EF, regional perfusion, regional wall motion and regional wall thickening were determined using a 20-segment model. Despite the presence of similar regional wall motion impairment in patients with and patients without septal infarction, in terms of regional EF (2.5%+/-3% vs 1.9%+/-4.9% p=NS) and inward septal motion (3+/-4.9 mm vs 2.3+/-6.1 mm p=NS), significant differences were observed in both perfusion (74.7%+/-6.2% vs 63.3%+/-13%, p>0.0001) and regional wall thickening (17.2%+/-7.4% vs 12.6%+/-7.2%, p>0.0001). Gated SPECT with perfusion tracers can reliably differentiate pseudo-paradoxical from true paradoxical septal motion in patients with previous CABG, and it may be the method of choice for evaluating left ventricular performance in this patient population.

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.

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.

Magnetic particle imaging: from proof of principle to preclinical applications

NASA Astrophysics Data System (ADS)

Knopp, T.; Gdaniec, N.; Möddel, M.

2017-07-01

Tomographic imaging has become a mandatory tool for the diagnosis of a majority of diseases in clinical routine. Since each method has its pros and cons, a variety of them is regularly used in clinics to satisfy all application needs. Magnetic particle imaging (MPI) is a relatively new tomographic imaging technique that images magnetic nanoparticles with a high spatiotemporal resolution in a quantitative way, and in turn is highly suited for vascular and targeted imaging. MPI was introduced in 2005 and now enters the preclinical research phase, where medical researchers get access to this new technology and exploit its potential under physiological conditions. Within this paper, we review the development of MPI since its introduction in 2005. Besides an in-depth description of the basic principles, we provide detailed discussions on imaging sequences, reconstruction algorithms, scanner instrumentation and potential medical applications.

Modeling the Western Diet for Preclinical Investigations.

PubMed

Hintze, Korry J; Benninghoff, Abby D; Cho, Clara E; Ward, Robert E

2018-05-01

Rodent models have been invaluable for biomedical research. Preclinical investigations with rodents allow researchers to investigate diseases by using study designs that are not suitable for human subjects. The primary criticism of preclinical animal models is that results are not always translatable to humans. Some of this lack of translation is due to inherent differences between species. However, rodent models have been refined over time, and translatability to humans has improved. Transgenic animals have greatly aided our understanding of interactions between genes and disease and have narrowed the translation gap between humans and model animals. Despite the technological innovations of animal models through advances in genetics, relatively little attention has been given to animal diets. Namely, developing diets that replicate what humans eat will help make animal models more relevant to human populations. This review focuses on commonly used rodent diets that are used to emulate the Western dietary pattern in preclinical studies of obesity and type 2 diabetes, nonalcoholic liver disease, maternal nutrition, and colorectal cancer.

Dissolution DNP for in vivo preclinical studies

NASA Astrophysics Data System (ADS)

Comment, Arnaud

2016-03-01

The tremendous polarization enhancement afforded by dissolution dynamic nuclear polarization (DNP) can be taken advantage of to perform preclinical in vivo molecular and metabolic imaging. Following the injection of molecules that are hyperpolarized via dissolution DNP, real-time measurements of their biodistribution and metabolic conversion can be recorded. This technology therefore provides a unique and invaluable tool for probing cellular metabolism in vivo in animal models in a noninvasive manner. It gives the opportunity to follow and evaluate disease progression and treatment response without requiring ex vivo destructive tissue assays. Although its considerable potential has now been widely recognized, hyperpolarized magnetic resonance by dissolution DNP remains a challenging method to implement for routine in vivo preclinical measurements. The aim of this article is to provide an overview of the current state-of-the-art technology for preclinical applications and the challenges that need to be addressed to promote it and allow its wider dissemination in the near future.

The basics of preclinical drug development for neurodegenerative disease indications.

PubMed

Steinmetz, Karen L; Spack, Edward G

2009-06-12

Preclinical development encompasses the activities that link drug discovery in the laboratory to initiation of human clinical trials. Preclinical studies can be designed to identify a lead candidate from several hits; develop the best procedure for new drug scale-up; select the best formulation; determine the route, frequency, and duration of exposure; and ultimately support the intended clinical trial design. The details of each preclinical development package can vary, but all have some common features. Rodent and nonrodent mammalian models are used to delineate the pharmacokinetic profile and general safety, as well as to identify toxicity patterns. One or more species may be used to determine the drug's mean residence time in the body, which depends on inherent absorption, distribution, metabolism, and excretion properties. For drugs intended to treat Alzheimer's disease or other brain-targeted diseases, the ability of a drug to cross the blood brain barrier may be a key issue. Toxicology and safety studies identify potential target organs for adverse effects and define the Therapeutic Index to set the initial starting doses in clinical trials. Pivotal preclinical safety studies generally require regulatory oversight as defined by US Food and Drug Administration (FDA) Good Laboratory Practices and international guidelines, including the International Conference on Harmonization. Concurrent preclinical development activities include developing the Clinical Plan and preparing the new drug product, including the associated documentation to meet stringent FDA Good Manufacturing Practices regulatory guidelines. A wide range of commercial and government contract options are available for investigators seeking to advance their candidate(s). Government programs such as the Small Business Innovative Research and Small Business Technology Transfer grants and the National Institutes of Health Rapid Access to Interventional Development Pilot Program provide funding and

The basics of preclinical drug development for neurodegenerative disease indications

PubMed Central

Steinmetz, Karen L; Spack, Edward G

2009-01-01

Preclinical development encompasses the activities that link drug discovery in the laboratory to initiation of human clinical trials. Preclinical studies can be designed to identify a lead candidate from several hits; develop the best procedure for new drug scale-up; select the best formulation; determine the route, frequency, and duration of exposure; and ultimately support the intended clinical trial design. The details of each preclinical development package can vary, but all have some common features. Rodent and nonrodent mammalian models are used to delineate the pharmacokinetic profile and general safety, as well as to identify toxicity patterns. One or more species may be used to determine the drug's mean residence time in the body, which depends on inherent absorption, distribution, metabolism, and excretion properties. For drugs intended to treat Alzheimer's disease or other brain-targeted diseases, the ability of a drug to cross the blood brain barrier may be a key issue. Toxicology and safety studies identify potential target organs for adverse effects and define the Therapeutic Index to set the initial starting doses in clinical trials. Pivotal preclinical safety studies generally require regulatory oversight as defined by US Food and Drug Administration (FDA) Good Laboratory Practices and international guidelines, including the International Conference on Harmonisation. Concurrent preclinical development activities include developing the Clinical Plan and preparing the new drug product, including the associated documentation to meet stringent FDA Good Manufacturing Practices regulatory guidelines. A wide range of commercial and government contract options are available for investigators seeking to advance their candidate(s). Government programs such as the Small Business Innovative Research and Small Business Technology Transfer grants and the National Institutes of Health Rapid Access to Interventional Development Pilot Program provide funding and

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.

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.

The case for introducing pre-registered confirmatory pharmacological pre-clinical studies.

PubMed

Kiwanuka, Olivia; Bellander, Bo-Michael; Hånell, Anders

2018-05-01

When evaluating the design of pre-clinical studies in the field of traumatic brain injury, we found substantial differences compared to phase III clinical trials, which in part may explain the difficulties in translating promising experimental drugs into approved treatments. By using network analysis, we also found cases where a large proportion of the studies evaluating a pre-clinical treatment was performed by inter-related researchers, which is potentially problematic. Subjecting all pre-clinical trials to the rigor of a phase III clinical trial is, however, likely not practically achievable. Instead, we repeat the call for a distinction to be made between exploratory and confirmatory pre-clinical studies.

Estimating Lymphodynamic Conditions and Lymphovenous Anastomosis Efficacy Using 99mTc-phytate Lymphoscintigraphy with SPECT-CT in Patients with Lower-limb Lymphedema

PubMed Central

Fukushima, Yoshimitsu; Kumita, Shinichiro; Ogawa, Rei; Hyakusoku, Hiko

2015-01-01

Background: Diagnostic and therapeutic strategies for lower-limb lymphedema have not yet been established. The purpose of this study was to estimate the lymphodynamic condition and therapeutic efficacy of lymphovenous anastomosis (LVA) in lower-limb lymphedema patients using 2-phase 99mTc-phytate lymphoscintigraphy with single-photon emission computed tomography-computed tomography (SPECT-CT). Methods: In this study, consecutive patients with lower-limb lymphedema who underwent 2-phase lymphoscintigraphy using 99mTc-phytate were enrolled between June 2013 and June 2014. SPECT-CT was also performed to clarify the relationships between functional and morphological information. In both the early and delayed images, inguinal lymph node accumulation, dermal backflow, and their sequential alternations were evaluated, and liver-to-blood ratio and inguinal lymph node-to-blood ratio were calculated. All participants were classified into 6 types of lymphodynamic conditions based on the image findings. Patients with both dermal backflow and associated normal lymphatic vessel accumulation proceeded to LVA and underwent a second lymphoscintigraphy after the operation. Results: Of all 30 participants, the largest population was categorized as type 4, which had consistent inguinal lymph node accumulation defect with dermal backflow. In 12 operated cases, dermal backflow was degraded in 10 cases by LVA. Liver-to-blood ratio in both early and delayed images and inguinal lymph node-to-blood ratio in delayed image significantly increased after LVA. Conclusions: Lymphoscintigraphy with SPECT-CT can provide both functional and morphological information simultaneously in patients with lower-limb lymphedema. Using these procedures, a type categorization for the patients was devised, which reflects their lymphodynamic conditions. The therapeutic efficacy of LVA could also be estimated quantitatively by the derived findings. PMID:26090294

Introduction of a novel ultrahigh sensitivity collimator for brain SPECT imaging

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

Park, Mi-Ae, E-mail: miaepark@bwh.harvard.edu; Kij

Purpose: Noise levels of brain SPECT images are highest in central regions, due to preferential attenuation of photons emitted from deep structures. To address this problem, the authors have designed a novel collimator for brain SPECT imaging that yields greatly increased sensitivity near the center of the brain without loss of resolution. This hybrid collimator consisted of ultrashort cone-beam holes in the central regions and slant-holes in the periphery (USCB). We evaluated this collimator for quantitative brain imaging tasks. Methods: Owing to the uniqueness of the USCB collimation, the hole pattern required substantial variations in collimator parameters. To utilize themore » lead-casting technique, the authors designed two supporting plates to position about 37 000 hexagonal, slightly tapered pins. The holes in the supporting plates were modeled to yield the desired focal length, hole length, and septal thickness. To determine the properties of the manufactured collimator and to compute the system matrix, the authors prepared an array of point sources that covered the entire detector area. Each point source contained 32 μCi of Tc-99m at the first scan time. The array was imaged for 5 min at each of the 64 shifted locations to yield a 2-mm sampling distance, and hole parameters were calculated. The sensitivity was also measured using a point source placed along the central ray at several distances from the collimator face. High-count projection data from a five-compartment brain phantom were acquired with the three collimators on a dual-head SPECT/CT system. The authors calculated Cramer-Rao bounds on the precision of estimates of striatal and background activity concentration. In order to assess the new collimation system to detect changes in striatal activity, the authors evaluated the precision of measuring a 5% decrease in right putamen activity. The authors also reconstructed images of projection data obtained by summing data from the individual

Cardiac contraction motion compensation in gated myocardial perfusion SPECT: A comparative study.

PubMed

Salehi, Narges; Rahmim, Arman; Fatemizadeh, Emad; Akbarzadeh, Afshin; Farahani, Mohammad Hossein; Farzanefar, Saeed; Ay, Mohammad Reza

2018-05-01

Cardiac contraction significantly degrades quality and quantitative accuracy of gated myocardial perfusion SPECT (MPS) images. In this study, we aimed to explore different techniques in motion-compensated temporal processing of MPS images and their impact on image quality and quantitative accuracy. 50 patients without known heart condition underwent gated MPS. 3D motion compensation methods using Motion Freezing by Cedars Sinai (MF), Log-domain Diffeomorphic Demons (LDD) and Free-Form Deformation (FFD) were applied to warp all image phases to fit the end-diastolic (ED) phase. Afterwards, myocardial wall thickness, myocardial to blood pool contrast, and image contrast-to noise ratio (CNR) were measured in summed images with no motion compensation (NoMC) and compensated images (MF, LDD and FFD). Total Perfusion Defect (TPD) was derived from Cedars-Sinai software, on the basis of sex-specific normal limits. Left ventricle (LV) lateral wall thickness was reduced after applying motion compensation (p < 0.05). Myocardial to blood pool contrast and CNR in compensated images were greater than NoMC (p < 0.05). TPD_LDD was in good agreement with the corresponding TPD_MF (p = 0.13). All methods have improved image quality and quantitative performance relative to NoMC. LDD and FFD are fully automatic and do not require any manual intervention, while MF is dependent on contour definition. In terms of diagnostic parameters LDD is in good agreement with MF which is a clinically accepted method. Further investigation along with diagnostic reference standards, in order to specify diagnostic value of each technique is recommended. Copyright © 2018 Associazione Italiana di Fisica Medica. All rights reserved.

Diagnostic accuracy of semi-automatic quantitative metrics as an alternative to expert reading of CT myocardial perfusion in the CORE320 study.

PubMed

Ostovaneh, Mohammad R; Vavere, Andrea L; Mehra, Vishal C; Kofoed, Klaus F; Matheson, Matthew B; Arbab-Zadeh, Armin; Fujisawa, Yasuko; Schuijf, Joanne D; Rochitte, Carlos E; Scholte, Arthur J; Kitagawa, Kakuya; Dewey, Marc; Cox, Christopher; DiCarli, Marcelo F; George, Richard T; Lima, Joao A C

To determine the diagnostic accuracy of semi-automatic quantitative metrics compared to expert reading for interpretation of computed tomography perfusion (CTP) imaging. The CORE320 multicenter diagnostic accuracy clinical study enrolled patients between 45 and 85 years of age who were clinically referred for invasive coronary angiography (ICA). Computed tomography angiography (CTA), CTP, single photon emission computed tomography (SPECT), and ICA images were interpreted manually in blinded core laboratories by two experienced readers. Additionally, eight quantitative CTP metrics as continuous values were computed semi-automatically from myocardial and blood attenuation and were combined using logistic regression to derive a final quantitative CTP metric score. For the reference standard, hemodynamically significant coronary artery disease (CAD) was defined as a quantitative ICA stenosis of 50% or greater and a corresponding perfusion defect by SPECT. Diagnostic accuracy was determined by area under the receiver operating characteristic curve (AUC). Of the total 377 included patients, 66% were male, median age was 62 (IQR: 56, 68) years, and 27% had prior myocardial infarction. In patient based analysis, the AUC (95% CI) for combined CTA-CTP expert reading and combined CTA-CTP semi-automatic quantitative metrics was 0.87(0.84-0.91) and 0.86 (0.83-0.9), respectively. In vessel based analyses the AUC's were 0.85 (0.82-0.88) and 0.84 (0.81-0.87), respectively. No significant difference in AUC was found between combined CTA-CTP expert reading and CTA-CTP semi-automatic quantitative metrics in patient based or vessel based analyses(p > 0.05 for all). Combined CTA-CTP semi-automatic quantitative metrics is as accurate as CTA-CTP expert reading to detect hemodynamically significant CAD. Copyright © 2018 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Considering sex as a biological variable in preclinical research.

PubMed

Miller, Leah R; Marks, Cheryl; Becker, Jill B; Hurn, Patricia D; Chen, Wei-Jung; Woodruff, Teresa; McCarthy, Margaret M; Sohrabji, Farida; Schiebinger, Londa; Wetherington, Cora Lee; Makris, Susan; Arnold, Arthur P; Einstein, Gillian; Miller, Virginia M; Sandberg, Kathryn; Maier, Susan; Cornelison, Terri L; Clayton, Janine A

2017-01-01

In June 2015, the National Institutes of Health (NIH) released a Guide notice (NOT-OD-15-102) that highlighted the expectation of the NIH that the possible role of sex as a biologic variable be factored into research design, analyses, and reporting of vertebrate animal and human studies. Anticipating these guidelines, the NIH Office of Research on Women's Health, in October 2014, convened key stakeholders to discuss methods and techniques for integrating sex as a biologic variable in preclinical research. The workshop focused on practical methods, experimental design, and approaches to statistical analyses in the use of both male and female animals, cells, and tissues in preclinical research. Workshop participants also considered gender as a modifier of biology. This article builds on the workshop and is meant as a guide to preclinical investigators as they consider methods and techniques for inclusion of both sexes in preclinical research and is not intended to prescribe exhaustive/specific approaches for compliance with the new NIH policy.-Miller, L. R., Marks, C., Becker, J. B., Hurn, P. D., Chen, W.-J., Woodruff, T., McCarthy, M. M., Sohrabji, F., Schiebinger, L., Wetherington, C. L., Makris, S., Arnold, A. P., Einstein, G., Miller, V. M., Sandberg, K., Maier, S., Cornelison, T. L., Clayton, J. A. Considering sex as a biological variable in preclinical research. © FASEB.

Effectiveness of project ACORDE materials: applied evaluative research in a preclinical technique course.

PubMed

Shugars, D A; Trent, P J; Heymann, H O

1979-08-01

Two instructional strategies, the traditional lecture method and a standardized self-instructional (ACORDE) format, were compared for efficiency and perceived usefulness in a preclinical restorative dentistry technique course through the use of a posttest-only control group research design. Control and experimental groups were compared on (a) technique grades, (b) didactic grades, (c) amount of time spent, (d) student and faculty perceptions, and (e) observation of social dynamics. The results of this study demonstrated the effectiveness of Project ACORDE materials in teaching dental students, provided an example of applied research designed to test contemplated instructional innovations prior to use and used a method which highlighted qualitative, as well as quantitative, techniques for data gathering in applied research.

Study partners should be required in preclinical Alzheimer's disease trials.

PubMed

Grill, Joshua D; Karlawish, Jason

2017-12-06

In an effort to intervene earlier in Alzheimer's disease (AD), clinical trials are testing promising candidate therapies in preclinical disease. Preclinical AD trial participants are cognitively normal, functionally independent, and autonomous decision-makers. Yet, like AD dementia trials, preclinical trials require dual enrollment of a participant and a knowledgeable informant, or study partner. The requirement of dyadic enrollment is a barrier to recruitment and may present unique ethical challenges. Despite these limitations, the requirement should continue. Study partners may be essential to ensure participant safety and wellbeing, including overcoming distress related to biomarker disclosure and minimizing risk for catastrophic reactions and suicide. The requirement may maximize participant retention and ensure data integrity, including that study partners are the source of data that will ultimately instruct whether a new treatment has a clinical benefit and meaningful impact on the population health burden associated with AD. Finally, study partners are needed to ensure the scientific and clinical value of trials. Preclinical AD will represent a new model of care, in which persons with no symptoms are informed of probable cognitive decline and eventual dementia. The rationale for early diagnosis in symptomatic AD is equally applicable in preclinical AD-to minimize risk, maximize quality of life, and ensure optimal planning and communication. Family members and other sources of support will likely be essential to the goals of this new model of care for preclinical AD patients and trials must instruct this clinical practice.

SPECT bone scintigraphy for the assessment of condylar growth activity in mandibular asymmetry: is it accurate?

PubMed

Chan, B H; Leung, Y Y

2018-04-01

The comparison of serial radiographs and clinical photographs is considered the current accepted standard for the diagnosis of active condylar hyperplasia in patients with facial asymmetry. Single photon emission computed tomography (SPECT) has recently been proposed as an alternative method. SPECT can be interpreted using three reported methods absolute difference in uptake, uptake ratio, and relative uptake. SPECT findings were compared to those from serial comparisons of radiographs and clinical photographs taken at the time of SPECT and a year later; the sensitivities and specificities were determined. Two hundred patient scans were evaluated. Thirty-four patients showed active growth on serial growth assessment. On comparison with serial growth assessment, the sensitivity and specificity of the three methods ranged between 32.4% and 67.6%, and 36.1% and 78.3%, respectively. Analysis using receiver operating characteristic (ROC) curves revealed area under the curve (AUC) values of <0.58. The average age (mean±standard deviation) of patients with active growth was 18.6±2.8 years, and average growth in the anteroposterior, vertical, and transverse directions was 0.94±0.91mm, 0.88±0.86mm, and 1.4±0.66 mm, respectively. With such low sensitivity and specificity values, it is not justifiable to use SPECT in place of serial growth assessment for the determination of condylar growth status. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

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.

Preoperative 4D CT Localization of Nonlocalizing Parathyroid Adenomas by Ultrasound and SPECT-CT.

PubMed

Hinson, Andrew M; Lee, David R; Hobbs, Bradley A; Fitzgerald, Ryan T; Bodenner, Donald L; Stack, Brendan C

2015-11-01

To evaluate 4-dimensional (4D) computed tomography (CT) for the localization of parathyroid adenomas previously considered nonlocalizing on ultrasound and single-photon emission CT with CT scanning (SPECT-CT). To measure radiation exposure associated with 4D-CT and compared it with SPECT-CT. Case series with chart review. University tertiary hospital. Nineteen adults with primary hyperparathyroidism who underwent preoperative 4D CT from November 2013 through July 2014 after nonlocalizing preoperative ultrasound and technetium-99m SPECT-CT scans. Sensitivity, specificity, predictive values, and accuracy of 4D CT were evaluated. Nineteen patients (16 women and 3 men) were included with a mean age of 66 years (range, 39-80 years). Mean preoperative parathyroid hormone level was 108.5 pg/mL (range, 59.3-220.9 pg/mL), and mean weight of the excised gland was 350 mg (range, 83-797 mg). 4D CT sensitivity and specificity for localization to the patient's correct side of the neck were 84.2% and 81.8%, respectively; accuracy was 82.9%. The sensitivity for localizing adenomas to the correct quadrant was 76.5% and 91.5%, respectively; accuracy was 88.2%. 4D CT radiation exposure was significantly less than the radiation associated with SPECT-CT (13.8 vs 18.4 mSv, P = 0.04). 4D CT localizes parathyroid adenomas with relatively high sensitivity and specificity and allows for the localization of some adenomas not observed on other sestamibi-based scans. 4D CT was also associated with less radiation exposure when compared with SPECT-CT based on our study protocol. 4D CT may be considered as first- or second-line imaging for localizing parathyroid adenomas in the setting of primary hyperparathyroidism. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

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.

Estimation of myocardial flow reserve utilizing an ultrafast cardiac SPECT: Comparison with coronary angiography, fractional flow reserve, and the SYNTAX score.

PubMed

Miyagawa, Masao; Nishiyama, Yoshiko; Uetani, Teruyoshi; Ogimoto, Akiyoshi; Ikeda, Shuntaro; Ishimura, Hayato; Watanabe, Emiri; Tashiro, Rami; Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Mochizuki, Teruhito

2017-10-01

Quantitative assessment of myocardial flow reserve (MFR) by single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is challenging but may facilitate evaluation of multi-vessel coronary artery disease (CAD). We enrolled 153 patients with suspected or known CAD, referred for pharmacological stress MPI. They underwent a 99m Tc-perfusion stress/rest SPECT with an ultrafast cadmium-zinc-telluride (CZT) camera. Dynamic data were acquired and time-activity curves fitted to a 1-tissue compartment analysis with input function. K1 was assigned for stress and rest data. The MFR index (MFRi) was calculated as K1 stress/K1 at-rest. The findings were validated by invasive coronary angiography in 69 consecutive patients. The global MFRi was 1.46 (1.16-1.76), 1.33 (1.12-1.54), and 1.18 (1.01-1.35), for 1-vessel disease (VD), 2-VD, and 3-VD, respectively. In the 3-VD, global MFRi was lower than that in 0-VD (1.63 [1.22-2.04], P<0.0001) and 1-VD (P=0.003). Multivariate logistic regression analysis for 3-VD showed significant associations with smoking history (odds ratio [OR]: 4.4 [0.4-8.4]), left ventricular ejection fraction (OR: 61.6 [57.5-66.0]), and global MFRi (OR: 119.6 [111.5-127.7], P=0.002). A cut-off value of 1.3 yielded 93.3% sensitivity and 75.9% specificity for diagnosing 3-VD. Fractional flow reserve positively correlated with regional MFRi (r=0.62, P=0.008), and the SYNTAX score correlated negatively with global MFRi (r=0.567, P=0.0003). We developed and validated a clinically available method for MFR quantification by dynamic 99m Tc-perfusion SPECT utilizing a CZT camera, which improves the detectability of multi-vessel CAD. Copyright © 2017 Elsevier B.V. All rights reserved.

The neuropsychology of normal aging and preclinical Alzheimer's disease.

PubMed

Caselli, Richard J; Locke, Dona E C; Dueck, Amylou C; Knopman, David S; Woodruff, Bryan K; Hoffman-Snyder, Charlene; Rademakers, Rosa; Fleisher, Adam S; Reiman, Eric M

2014-01-01

A National Institute on Aging-sponsored work group on preclinical Alzheimer's disease (AD) articulated the need to characterize cognitive differences between normal aging and preclinical AD. Seventy-one apolipoprotein E (APOE) ε4 homozygotes, 194 ε3/ε4 heterozygotes, and 356 ε4 noncarriers age 21 to 87 years who were cognitively healthy underwent neuropsychological testing every 2 years. Longitudinal trajectories of test scores were compared between APOE subgroups. There was a significant effect of age on all cognitive domains in both APOE ε4 carriers and noncarriers. A significant effect of APOE ε4 gene dose was confined to the memory domain and the Dementia Rating Scale. Cross-sectional comparisons did not discriminate the groups. Although cognitive aging patterns are similar in APOE ε4 carriers and noncarriers, preclinical AD is characterized by a significant ε4 gene dose effect that impacts memory and is detectable longitudinally. Preclinical neuropsychological testing strategies should emphasize memory-sensitive measures and longitudinal design. Copyright © 2014 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

A line-source method for aligning on-board and other pinhole SPECT systems

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

Yan, Susu; Bowsher, James; Yin, Fang-Fang

2013-12-15

Purpose: In order to achieve functional and molecular imaging as patients are in position for radiation therapy, a robotic multipinhole SPECT system is being developed. Alignment of the SPECT system—to the linear accelerator (LINAC) coordinate frame and to the coordinate frames of other on-board imaging systems such as cone-beam CT (CBCT)—is essential for target localization and image reconstruction. An alignment method that utilizes line sources and one pinhole projection is proposed and investigated to achieve this goal. Potentially, this method could also be applied to the calibration of the other pinhole SPECT systems.Methods: An alignment model consisting of multiple alignmentmore » parameters was developed which maps line sources in three-dimensional (3D) space to their two-dimensional (2D) projections on the SPECT detector. In a computer-simulation study, 3D coordinates of line-sources were defined in a reference room coordinate frame, such as the LINAC coordinate frame. Corresponding 2D line-source projections were generated by computer simulation that included SPECT blurring and noise effects. The Radon transform was utilized to detect angles (α) and offsets (ρ) of the line-source projections. Alignment parameters were then estimated by a nonlinear least squares method, based on the α and ρ values and the alignment model. Alignment performance was evaluated as a function of number of line sources, Radon transform accuracy, finite line-source width, intrinsic camera resolution, Poisson noise, and acquisition geometry. Experimental evaluations were performed using a physical line-source phantom and a pinhole-collimated gamma camera attached to a robot.Results: In computer-simulation studies, when there was no error in determining angles (α) and offsets (ρ) of the measured projections, six alignment parameters (three translational and three rotational) were estimated perfectly using three line sources. When angles (α) and offsets (ρ) were

MIDG-Emerging grid technologies for multi-site preclinical molecular imaging research communities.

PubMed

Lee, Jasper; Documet, Jorge; Liu, Brent; Park, Ryan; Tank, Archana; Huang, H K

2011-03-01

Molecular imaging is the visualization and identification of specific molecules in anatomy for insight into metabolic pathways, tissue consistency, and tracing of solute transport mechanisms. This paper presents the Molecular Imaging Data Grid (MIDG) which utilizes emerging grid technologies in preclinical molecular imaging to facilitate data sharing and discovery between preclinical molecular imaging facilities and their collaborating investigator institutions to expedite translational sciences research. Grid-enabled archiving, management, and distribution of animal-model imaging datasets help preclinical investigators to monitor, access and share their imaging data remotely, and promote preclinical imaging facilities to share published imaging datasets as resources for new investigators. The system architecture of the Molecular Imaging Data Grid is described in a four layer diagram. A data model for preclinical molecular imaging datasets is also presented based on imaging modalities currently used in a molecular imaging center. The MIDG system components and connectivity are presented. And finally, the workflow steps for grid-based archiving, management, and retrieval of preclincial molecular imaging data are described. Initial performance tests of the Molecular Imaging Data Grid system have been conducted at the USC IPILab using dedicated VMware servers. System connectivity, evaluated datasets, and preliminary results are presented. The results show the system's feasibility, limitations, direction of future research. Translational and interdisciplinary research in medicine is increasingly interested in cellular and molecular biology activity at the preclinical levels, utilizing molecular imaging methods on animal models. The task of integrated archiving, management, and distribution of these preclinical molecular imaging datasets at preclinical molecular imaging facilities is challenging due to disparate imaging systems and multiple off-site investigators. A

Imaging of mild traumatic brain injury using 57Co and 99mTc HMPAO SPECT as compared to other diagnostic procedures.

PubMed

Audenaert, Kurt; Jansen, Hugo M L; Otte, Andreas; Peremans, Kathelijne; Vervaet, Myriam; Crombez, Roger; de Ridder, Leo; van Heeringen, Cees; Thirot, Joel; Dierckx, Rudi; Korf, Jaap

2003-10-01

Traumatic brain injury (TBI) is usually assessed with the Glasgow Coma Scale (GCS), CT and EEG. TBI can result from either the primary mechanical impact or secondary (ischemic) brain damage, in which calcium (Ca) plays a pivotal role. This study was undertaken to compare the applicability of SPECT using 57Co as a Ca-tracer in patients with mild traumatic brain injury. 8 patients with mild TBI (GCS 15) were clinically examined and studied with EEG, neuropsychological testing (NPT) and SPECT within 2 days post-TBI. After i.v.-administration of 37 MBq (1 mCi) 57Co (effective radiation dose 0.34 mSv x MBq(-1); 1.24 rem x mCi(-1); physical half-life 270 days, biological half-life 37.6 h), single-headed SPECT (12 h pi) was performed, consecutively followed by standard 925 MBq (25 mCi) Tc-99m HMPAO SPECT. In 6 of the 8 patients, baseline NPT and SPECT showed focal abnormalities in the affected frontal and temporal brain regions, which were in good topographical accordance. CT and EEG did not detect (structural) lesions in any of these cases. Single-headed 57Co-SPECT is able to show the site and extent of brain damage in patients with mild TBI, even in the absence of structural lesions. It may confirm and localize NPT findings. The predictive value of 57Co-SPECT should be assessed in larger patient series.

Quantitative angiographic anatomy of the renal arteries and adjacent aorta in the swine for preclinical studies of intravascular catheterization devices.

PubMed

Sakaoka, Atsushi; Koshimizu, Masafumi; Nakamura, Shintaro; Matsumura, Kiyoshi

2018-05-10

Swine are the most common animal model in preclinical studies of cardiovascular devices. Because of the recent trend for development of new devices for percutaneous catheterization, especially for the renal arteries (RAs), we examined the quantitative anatomical dimensions of the RAs and adjacent aorta in swine. Angiographic images were analyzed in 66 female Yorkshire/Landrace crossbred swine. The diameter of both the right and left main RA was 5.4 ± 0.6 mm. The length of the right main RA was significantly longer than that of the left (29.8 ± 7.5 mm vs. 20.6 ± 5.4 mm, respectively; P<0.001). The diameter of both the right and left branch RA with diameters ≥3 mm (the target vessel diameter of recently developed devices) was 3.8 ± 0.5 mm. The right branch RA was significantly longer than that of the left (18.9 ± 7.8 mm vs. 16.4 ± 7.4 mm, respectively; P<0.05). The branching angle of the right RA from the aorta was significantly smaller than that of the left (91 ± 12° vs. 103 ± 15°, respectively; P<0.001). The diameters of the suprarenal and infrarenal aorta were 10.6 ± 1.1 mm and 9.7 ± 0.9 mm, respectively. In conclusion, because of their similar dimensions to human, swine are an appropriate animal model for assessing the safety of, and determining optimal design of, catheter devices for RAs in simulated clinical use. However, there were species differences in the branching angle and adjacent aorta diameter, suggesting that swine models alone are inadequate to assess the delivery performance of catheter devices for RAs.

Quantitative angiographic anatomy of the renal arteries and adjacent aorta in the swine for preclinical studies of intravascular catheterization devices

PubMed Central

Sakaoka, Atsushi; Koshimizu, Masafumi; Nakamura, Shintaro; Matsumura, Kiyoshi

2018-01-01

Swine are the most common animal model in preclinical studies of cardiovascular devices. Because of the recent trend for development of new devices for percutaneous catheterization, especially for the renal arteries (RAs), we examined the quantitative anatomical dimensions of the RAs and adjacent aorta in swine. Angiographic images were analyzed in 66 female Yorkshire/Landrace crossbred swine. The diameter of both the right and left main RA was 5.4 ± 0.6 mm. The length of the right main RA was significantly longer than that of the left (29.8 ± 7.5 mm vs. 20.6 ± 5.4 mm, respectively; P<0.001). The diameter of both the right and left branch RA with diameters ≥3 mm (the target vessel diameter of recently developed devices) was 3.8 ± 0.5 mm. The right branch RA was significantly longer than that of the left (18.9 ± 7.8 mm vs. 16.4 ± 7.4 mm, respectively; P<0.05). The branching angle of the right RA from the aorta was significantly smaller than that of the left (91 ± 12° vs. 103 ± 15°, respectively; P<0.001). The diameters of the suprarenal and infrarenal aorta were 10.6 ± 1.1 mm and 9.7 ± 0.9 mm, respectively. In conclusion, because of their similar dimensions to human, swine are an appropriate animal model for assessing the safety of, and determining optimal design of, catheter devices for RAs in simulated clinical use. However, there were species differences in the branching angle and adjacent aorta diameter, suggesting that swine models alone are inadequate to assess the delivery performance of catheter devices for RAs. PMID:29353822

Pathological Laughing: Brain SPECT Findings.

PubMed

Morland, David; Wolff, Valérie; Blondet, Cyrille; Marescaux, Christian; Namer, Izzie Jacques

2015-09-01

We present the case of a 40-year-old man consulting for uncontrollable episodes of laughing related to emotional lability and not systematically linked to feelings of happiness. Seven months earlier he had presented a pontine ischemic stroke related to an occlusion of the basilar and left vertebral arteries. No epileptic activity or new MRI brain lesions were found. Brain perfusion SPECT performed showed marked hypoperfusion in the right frontal inferior and temporoinsular regions, suggesting a diaschisis phenomenon caused by pontine lesions and highlighted laughing regulation pathways. The patient was successfully treated with a serotonergic reuptake inhibitor, fluoxetine.

SU-E-I-80: Quantification of Respiratory and Cardiac Motion Effect in SPECT Acquisitions Using Anthropomorphic Models: A Monte Carlo Simulation Study

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

Papadimitroulas, P; Kostou, T; Kagadis, G

Purpose: The purpose of the present study was to quantify, evaluate the impact of cardiac and respiratory motion on clinical nuclear imaging protocols. Common SPECT and scintigraphic scans are studied using Monte Carlo (MC) simulations, comparing the resulted images with and without motion. Methods: Realistic simulations were executed using the GATE toolkit and the XCAT anthropomorphic phantom as a reference model for human anatomy. Three different radiopharmaceuticals based on 99mTc were studied, namely 99mTc-MDP, 99mTc—N—DBODC and 99mTc—DTPA-aerosol for bone, myocardium and lung scanning respectively. The resolution of the phantom was set to 3.5 mm{sup 3}. The impact of the motionmore » on spatial resolution was quantified using a sphere with 3.5 mm diameter and 10 separate time frames, in the ECAM modeled SPECT scanner. Finally, respiratory motion impact on resolution and imaging of lung lesions was investigated. The MLEM algorithm was used for data reconstruction, while the literature derived biodistributions of the pharmaceuticals were used as activity maps in the simulations. Results: FWHM was extracted for a static and a moving sphere which was ∼23 cm away from the entrance of the SPECT head. The difference in the FWHM was 20% between the two simulations. Profiles in thorax were compared in the case of bone scintigraphy, showing displacement and blurring of the bones when respiratory motion was inserted in the simulation. Large discrepancies were noticed in the case of myocardium imaging when cardiac motion was incorporated during the SPECT acquisition. Finally the borders of the lungs are blurred when respiratory motion is included resulting to a dislocation of ∼2.5 cm. Conclusion: As we move to individualized imaging and therapy procedures, quantitative and qualitative imaging is of high importance in nuclear diagnosis. MC simulations combined with anthropomorphic digital phantoms can provide an accurate tool for applications like motion

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.

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

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.

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.

Myocardial perfusion and left ventricular function indices assessed by gated myocardial perfusion SPECT in methamphetamine abusers.

PubMed

Dadpour, Bita; Dabbagh Kakhki, Vahid R; Afshari, Reza; Dorri-Giv, Masoumeh; Mohajeri, Seyed A R; Ghahremani, Somayeh

2016-12-01

Methamphetamine (MA) is associated with alterations of cardiac structure and function, although it is less known. In this study, we assessed possible abnormality in myocardial perfusion and left ventricular function using gated myocardial perfusion SPECT. Fifteen patients with MA abuse, on the basis of Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) MA dependency determined by Structured Clinical Interview for DSM-IV, underwent 2-day dipyridamole stress/rest Tc-sestamibi gated myocardial perfusion SPECT. An average daily dose of MA use was 0.91±1.1 (0.2-4) g. The duration of MA use was 3.4±2.1 (1-7) years. In visual and semiquantitative analyses, all patients had normal gated myocardial perfusion SPECT, with no perfusion defects. In all gated SPECT images, there was no abnormality in left ventricular wall motion and thickening. All summed stress scores and summed rest scores were below 3. Calculated left ventricular functional indices including the end-diastolic volume, end-systolic volume, and left ventricular ejection fraction were normal. Many cardiac findings because of MA mentioned in previous reports are less likely because of significant epicardial coronary artery stenosis.

Preclinical Mouse Cancer Models: A Maze of Opportunities and Challenges

PubMed Central

Day, Chi-Ping; Merlino, Glenn; Van Dyke, Terry

2015-01-01

Significant advances have been made in developing novel therapeutics for cancer treatment, and targeted therapies have revolutionized the treatment of some cancers. Despite the promise, only about five percent of new cancer drugs are approved, and most fail due to lack of efficacy. The indication is that current preclinical methods are limited in predicting successful outcomes. Such failure exacts enormous cost, both financial and in the quality of human life. This primer explores the current status, promise and challenges of preclinical evaluation in advanced mouse cancer models and briefly addresses emerging models for early-stage preclinical development. PMID:26406370

In vivo detection of microstructural correlates of brain pathology in preclinical and early Alzheimer Disease with magnetic resonance imaging.

PubMed

Zhao, Yue; Raichle, Marcus E; Wen, Jie; Benzinger, Tammie L; Fagan, Anne M; Hassenstab, Jason; Vlassenko, Andrei G; Luo, Jie; Cairns, Nigel J; Christensen, Jon J; Morris, John C; Yablonskiy, Dmitriy A

2017-03-01

Alzheimer disease (AD) affects at least 5 million individuals in the USA alone stimulating an intense search for disease prevention and treatment therapies as well as for diagnostic techniques allowing early identification of AD during a long pre-symptomatic period that can be used for the initiation of prevention trials of disease-modifying therapies in asymptomatic individuals. Our approach to developing such techniques is based on the Gradient Echo Plural Contrast Imaging (GEPCI) technique that provides quantitative in vivo measurements of several brain-tissue-specific characteristics of the gradient echo MRI signal (GEPCI metrics) that depend on the integrity of brain tissue cellular structure. Preliminary data were obtained from 34 participants selected from the studies of aging and dementia at the Knight Alzheimer's Disease Research Center at Washington University in St. Louis. Cognitive status was operationalized with the Clinical Dementia Rating (CDR) scale. The participants, assessed as cognitively normal (CDR=0; n=23) or with mild AD dementia (CDR=0.5 or 1; n=11) underwent GEPCI MRI, a collection of cognitive performance tests and CSF amyloid (Aβ) biomarker Aβ 42 . A subset of 19 participants also underwent PET PiB studies to assess their brain Aβ burden. According to the Aβ status, cognitively normal participants were divided into normal (Aβ negative; n=13) and preclinical (Aβ positive; n=10) groups. GEPCI quantitative measurements demonstrated significant differences between all the groups: normal and preclinical, normal and mild AD, and preclinical and mild AD. GEPCI quantitative metrics characterizing tissue cellular integrity in the hippocampus demonstrated much stronger correlations with psychometric tests than the hippocampal atrophy. Importantly, GEPCI-determined changes in the hippocampal tissue cellular integrity were detected even in the hippocampal areas not affected by the atrophy. Our studies also uncovered strong correlations between

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.

Stakeholders' Perspectives on Preclinical Testing for Alzheimer's Disease.

PubMed

Arias, Jalayne J; Cummings, Jeffrey; Grant, Alexander Rae; Ford, Paul J

2015-01-01

Progress towards validating amyloid beta as an early indicator of Alzheimer's disease (AD) heightens the need for evaluation of stakeholders' perspectives of the benefits and harms of preclinical testing in asymptomatic individuals. Investigators conducted and analyzed 14 semi-structured interviews with family members of patients diagnosed with AD. Participants reported benefits, including the potential to seek treatment, make lifestyle changes, and prepare for cognitive impairment. Participants identified harms, including social harms, adverse life decisions, and psychological harms. Nine participants reported either a "positive global perspective" or a "positive global perspective (qualified)." Results from this study characterized stakeholders' perspectives on the potential benefits and harms of clinical use of preclinical testing for AD. Investigators used data from this study to develop a framework that contributes to ongoing discussions that will evaluate widespread adoption of preclinical testing and will inform future research. Copyright 2015 The Journal of Clinical Ethics. All rights reserved.

Limited-angle effect compensation for respiratory binned cardiac SPECT

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

Qi, Wenyuan; Yang, Yongyi, E-mail: yy@ece.iit.edu; Wernick, Miles N.

Purpose: In cardiac single photon emission computed tomography (SPECT), respiratory-binned study is used to combat the motion blur associated with respiratory motion. However, owing to the variability in respiratory patterns during data acquisition, the acquired data counts can vary significantly both among respiratory bins and among projection angles within individual bins. If not properly accounted for, such variation could lead to artifacts similar to limited-angle effect in image reconstruction. In this work, the authors aim to investigate several reconstruction strategies for compensating the limited-angle effect in respiratory binned data for the purpose of reducing the image artifacts. Methods: The authorsmore » first consider a model based correction approach, in which the variation in acquisition time is directly incorporated into the imaging model, such that the data statistics are accurately described among both the projection angles and respiratory bins. Afterward, the authors consider an approximation approach, in which the acquired data are rescaled to accommodate the variation in acquisition time among different projection angles while the imaging model is kept unchanged. In addition, the authors also consider the use of a smoothing prior in reconstruction for suppressing the artifacts associated with limited-angle effect. In our evaluation study, the authors first used Monte Carlo simulated imaging with 4D NCAT phantom wherein the ground truth is known for quantitative comparison. The authors evaluated the accuracy of the reconstructed myocardium using a number of metrics, including regional and overall accuracy of the myocardium, uniformity and spatial resolution of the left ventricle (LV) wall, and detectability of perfusion defect using a channelized Hotelling observer. As a preliminary demonstration, the authors also tested the different approaches on five sets of clinical acquisitions. Results: The quantitative evaluation results show that

Risk Stratification for Avascular Necrosis of the Femoral Head After Internal Fixation of Femoral Neck Fractures by Post-Operative Bone SPECT/CT.

PubMed

Han, Sangwon; Oh, Minyoung; Yoon, Seokho; Kim, Jinsoo; Kim, Ji-Wan; Chang, Jae-Suk; Ryu, Jin-Sook

2017-03-01

Avascular necrosis (AVN) of the femoral head is a major complication after internal fixation of a femoral neck fracture and determines the functional prognosis. We investigated postoperative bone single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing the risk of femoral head AVN. We retrospectively reviewed 53 consecutive patients who underwent bone SPECT/CT within 2 weeks of internal fixation of a femoral neck fracture and follow-up serial hip radiographs over at least 12 months. Nine patients developed femoral head AVN. In 15 patients who showed normal uptake on immediate postoperative SPECT/CT, no AVN occurred, whereas 9 of 38 patients who showed cold defects of the femoral head later developed AVN. The negative predictive value of immediate postoperative SPECT/CT for AVN was 100 %, whereas the positive predictive value was 24 %. Among 38 patients with cold defects, 1 developed AVN 3 months postoperatively. A follow-up bone SPECT/CT was performed in the other 37 patients at 2-10 months postoperatively. The follow-up bone SPECT/CT revealed completely normalized femoral head uptake in 27, partially normalized uptake in 8, and persistent cold defects in 2 patients. AVN developed in 3.7 % (1/27), 62.5 % (5/8), and 100 % (2/2) of each group, respectively. According to the time point of imaging, radiotracer uptake patterns of the femoral head on postoperative bone SPECT/CT indicate the risk of AVN after internal fixation of femoral neck fractures differently. Postoperative bone SPECT/CT may help orthopedic surgeons determine the appropriate follow-up of these patients.

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

Simultaneous 99mtc/111in spect reconstruction using accelerated convolution-based forced detection monte carlo

NASA Astrophysics Data System (ADS)

Karamat, Muhammad I.; Farncombe, Troy H.

2015-10-01

Simultaneous multi-isotope Single Photon Emission Computed Tomography (SPECT) imaging has a number of applications in cardiac, brain, and cancer imaging. The major concern however, is the significant crosstalk contamination due to photon scatter between the different isotopes. The current study focuses on a method of crosstalk compensation between two isotopes in simultaneous dual isotope SPECT acquisition applied to cancer imaging using 99mTc and 111In. We have developed an iterative image reconstruction technique that simulates the photon down-scatter from one isotope into the acquisition window of a second isotope. Our approach uses an accelerated Monte Carlo (MC) technique for the forward projection step in an iterative reconstruction algorithm. The MC estimated scatter contamination of a radionuclide contained in a given projection view is then used to compensate for the photon contamination in the acquisition window of other nuclide. We use a modified ordered subset-expectation maximization (OS-EM) algorithm named simultaneous ordered subset-expectation maximization (Sim-OSEM), to perform this step. We have undertaken a number of simulation tests and phantom studies to verify this approach. The proposed reconstruction technique was also evaluated by reconstruction of experimentally acquired phantom data. Reconstruction using Sim-OSEM showed very promising results in terms of contrast recovery and uniformity of object background compared to alternative reconstruction methods implementing alternative scatter correction schemes (i.e., triple energy window or separately acquired projection data). In this study the evaluation is based on the quality of reconstructed images and activity estimated using Sim-OSEM. In order to quantitate the possible improvement in spatial resolution and signal to noise ratio (SNR) observed in this study, further simulation and experimental studies are required.

99mTc MDP SPECT-CT-Based Modified Mirels Classification for Evaluation of Risk of Fracture in Skeletal Metastasis: A Pilot Study.

PubMed

Riaz, Saima; Bashir, Humayun; Niazi, Imran Khalid; Butt, Sumera; Qamar, Faisal

2018-06-01

Mirels' scoring system quantifies the risk of sustaining a pathologic fracture in osseous metastases of weight bearing long bones. Conventional Mirels' scoring is based on radiographs. Our pilot study proposes Tc MDP bone SPECT-CT based modified Mirels' scoring system and its comparison with conventional Mirels' scoring. Cortical lysis was noted in 8(24%) by SPECT-CT versus 2 (6.3%) on X-rays. Additional SPECT-CT parameters were; circumferential involvement [1/4 (31%), 1/2 (3%), 3/4 (37.5%), 4/4 (28%)] and extra-osseous soft tissue [3%]. Our pilot study suggests the potential role of SPECT-CT in predicting risk of fracture in osseous metastases.

The neuropsychology of normal aging and preclinical Alzheimer’s disease

PubMed Central

Caselli, Richard J.; Locke, Dona E.C.; Dueck, Amylou C.; Knopman, David S.; Woodruff, Bryan K.; Hoffman-Snyder, Charlene; Rademakers, Rosa; Fleisher, Adam S.; Reiman, Eric M.

2013-01-01

Background An NIA-sponsored workgroup on preclinical Alzheimer’s disease (AD) articulated the need to characterize cognitive differences between normal aging and preclinical AD. Methods 71 apolipoprotein E (APOE) e4 homozygotes (HMZ), 194 e3/4 heterozygotes (HTZ), and 356 e4 noncarriers (NC) aged 21–87 years who were cognitively healthy underwent neuropsychological testing every two years. Longitudinal trajectories of test scores were compared between APOE subgroups. Results There was a significant effect of age on all cognitive domains in both APOE e4 carriers and NC. A significant effect of APOE e4 gene dose was confined to the memory domain and the Dementia Rating Scale. Cross sectional comparisons did not discriminate the groups. Conclusions While cognitive aging patterns are similar in APOE e4 carriers and NC, preclinical AD is characterized by a significant e4 gene dose effect that impacts memory and is detectable longitudinally. Preclinical neuropsychological testing strategies should emphasize memory sensitive measures and longitudinal design. PMID:23541188

USHERING IN THE STUDY AND TREATMENT OF PRECLINICAL ALZHEIMER DISEASE

PubMed Central

Langbaum, Jessica B.S.; Fleisher, Adam S.; Chen, Kewei; Ayutyanont, Napatkamon; Lopera, Francisco; Quiroz, Yakeel T.; Caselli, Richard J.; Tariot, Pierre N.; Reiman, Eric M.

2014-01-01

Researchers have begun to characterize the subtle biological and cognitive processes that precede the clinical onset of Alzheimer disease (AD), and to set the stage for accelerated evaluation of experimental treatments to delay the onset, reduce the risk of or completely prevent clinical decline. Here, we provide an overview of the experimental strategies, and brain imaging and cerebrospinal fluid biomarker measures that are used in early detection and tracking of AD, highlighting at-risk individuals who could be suitable for preclinical monitoring. We discuss how these advances have contributed to reconceptualization of AD as a sequence of biological changes that occur during progression from preclinical AD, to mild cognitive impairment and finally dementia, and we review recently proposed research criteria for preclinical AD. Advances in the study of preclinical AD have driven the recognition that efficacy of at least some AD therapies may depend on initiation of treatment before clinical manifestation of disease, leading to a new era of AD prevention research. PMID:23752908

Ushering in the study and treatment of preclinical Alzheimer disease.

PubMed

Langbaum, Jessica B; Fleisher, Adam S; Chen, Kewei; Ayutyanont, Napatkamon; Lopera, Francisco; Quiroz, Yakeel T; Caselli, Richard J; Tariot, Pierre N; Reiman, Eric M

2013-07-01

Researchers have begun to characterize the subtle biological and cognitive processes that precede the clinical onset of Alzheimer disease (AD), and to set the stage for accelerated evaluation of experimental treatments to delay the onset, reduce the risk of, or completely prevent clinical decline. In this Review, we provide an overview of the experimental strategies, and brain imaging and cerebrospinal fluid biomarker measures that are used in early detection and tracking of AD, highlighting at-risk individuals who could be suitable for preclinical monitoring. We discuss how advances in the field have contributed to reconceptualization of AD as a sequence of biological changes that occur during progression from preclinical AD, to mild cognitive impairment and finally dementia, and we review recently proposed research criteria for preclinical AD. Advances in the study of preclinical AD have driven the recognition that efficacy of at least some AD therapies may depend on initiation of treatment before clinical manifestation of disease, leading to a new era of AD prevention research.

The Devil Is in the Details: Incomplete Reporting in Preclinical Animal Research.

PubMed

Avey, Marc T; Moher, David; Sullivan, Katrina J; Fergusson, Dean; Griffin, Gilly; Grimshaw, Jeremy M; Hutton, Brian; Lalu, Manoj M; Macleod, Malcolm; Marshall, John; Mei, Shirley H J; Rudnicki, Michael; Stewart, Duncan J; Turgeon, Alexis F; McIntyre, Lauralyn

2016-01-01

Incomplete reporting of study methods and results has become a focal point for failures in the reproducibility and translation of findings from preclinical research. Here we demonstrate that incomplete reporting of preclinical research is not limited to a few elements of research design, but rather is a broader problem that extends to the reporting of the methods and results. We evaluated 47 preclinical research studies from a systematic review of acute lung injury that use mesenchymal stem cells (MSCs) as a treatment. We operationalized the ARRIVE (Animal Research: Reporting of In Vivo Experiments) reporting guidelines for pre-clinical studies into 109 discrete reporting sub-items and extracted 5,123 data elements. Overall, studies reported less than half (47%) of all sub-items (median 51 items; range 37-64). Across all studies, the Methods Section reported less than half (45%) and the Results Section reported less than a third (29%). There was no association between journal impact factor and completeness of reporting, which suggests that incomplete reporting of preclinical research occurs across all journals regardless of their perceived prestige. Incomplete reporting of methods and results will impede attempts to replicate research findings and maximize the value of preclinical studies.

Low-frequency quantitative ultrasound imaging of cell death in vivo

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

Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J.

Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicatedmore » significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r{sup 2}= 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant

Myocardial viability assessment after acute myocardial infarction: low-dose dobutamine echocardiography versus rest-redistribution thallium-201 SPECT.

PubMed

Castini, D; Bestetti, A; Garbin, M; Di Leo, C; Bigi, R; Sponzilli, C; Concardi, G; Gioventù, M; Tarolo, G L; Lombardi, F; Fiorentini, C

1999-09-01

The presence of tissue viability is of great importance in the prognostic work-up of patients recovering from acute myocardial infarction. However, uncertainty still exists concerning the optimal tool for its assessment. The present study was undertaken in order to compare low-dose dobutamine echocardiography and rest-redistribution thallium SPECT for predicting late improvement of regional left ventricular function after acute myocardial infarction. Fifteen patients undergoing coronary angiography, low-dose dobutamine echocardiography and rest-redistribution thallium SPECT after thrombolyzed anterior acute myocardial infarction were studied. A 3 month follow-up echocardiogram was performed in all patients and 9 underwent coronary revascularization. A significant (> or = 70%) residual stenosis of the infarct-related artery was present in 14 patients, whilst a total occlusion was observed in 1. At 3 month follow-up, 41% of the dyssynergic segments improved. The sensitivity, specificity and accuracy for late wall motion improvement was 61, 89 and 77% for low-dose dobutamine echocardiography and, respectively, 76, 45 and 58% for rest-redistribution thallium SPECT. Tissue viability was detected in 65 and 31% of dyssynergic segments by rest-redistribution thallium SPECT and low-dose dobutamine echocardiography, respectively (p < 0.001). The agreement between the two techniques was 48%. Low-dose dobutamine echocardiography is more accurate than rest-redistribution thallium SPECT for predicting 3 month wall motion improvement in patients with acute anterior myocardial infarction, mainly due to its significantly better specificity.

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.

Harmonization in preclinical epilepsy research: A joint AES/ILAE translational initiative.

PubMed

Galanopoulou, Aristea S; French, Jacqueline A; O'Brien, Terence; Simonato, Michele

2017-11-01

Among the priority next steps outlined during the first translational epilepsy research workshop in London, United Kingdom (2012), jointly organized by the American Epilepsy Society (AES) and the International League Against Epilepsy (ILAE), are the harmonization of research practices used in preclinical studies and the development of infrastructure that facilitates multicenter preclinical studies. The AES/ILAE Translational Task Force of the ILAE has been pursuing initiatives that advance these goals. In this supplement, we present the first reports of the working groups of the Task Force that aim to improve practices of performing rodent video-electroencephalography (vEEG) studies in experimental controls, generate systematic reviews of preclinical research data, and develop preclinical common data elements (CDEs) for epilepsy research in animals. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Stress, Burnout and Coping Strategies in Preclinical Medical Students.

PubMed

Fares, Jawad; Al Tabosh, Hayat; Saadeddin, Zein; El Mouhayyar, Christopher; Aridi, Hussam

2016-02-01

It is acknowledged that physicians do not seek the same expert aid for themselves as they would offer their patients. In their preclinical years, medical students appear to espouse comparable behavior. To many, medicine is described as a never-ending path that places the student under heavy stress and burnout from the beginning, leaving him/her vulnerable and with insufficient coping methods. Hence, the objective of this study is to 1) explore the prevalence of stress and burnout among preclinical medical students, and 2) propose solutions to decrease stress and burnout and improve medical education in the preclinical years. A detailed scholarly research strategy using Google Scholar, Scopus, Embase, MEDLINE and PubMed was implemented to highlight key themes that are relevant to preclinical medical students' stress and burnout. Stress varied among different samples of medical students and ranged between 20.9% and 90%. Conversely, burnout ranged between 27% and 75%. Methods that help in reducing the incidence of stress and burnout by promoting strategies that focus on personal engagement, extracurricular activities, positive reinterpretation and expression of emotion, student-led mentorship programs, evaluation systems, career counseling and life coaching should be adopted.

Stress, Burnout and Coping Strategies in Preclinical Medical Students

PubMed Central