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  1. Assessment of an intermediate reprojection technique transitioning from planar to SPECT radionuclide ventriculography.

    PubMed

    O'Doherty, Jim; Rojas Fisher, Bruno; Price, Jonathan Mark; Wechalekar, Kshama

    2014-10-01

    The technique of SPECT-RNV (radionuclide ventriculography) offers a greater amount of clinically usable data than its planar counterpart (P-RNV). In transitioning from planar to SPECT-only acquisition methodologies, reprojection of the SPECT data can provide a planar dataset which can be used as an interim technique. The aim of this study was to test if reprojected planar images could be used as a surrogate for true planar images in SPECT-only setting. We performed SPECT-RNV and P-RNV on 47 patients on traditional sodium iodide (NaI) cameras, determining left ventricular ejection fractions (LVEF) for planar (EFP) and SPECT (EFS) techniques. We reprojected the SPECT-RNV data along the best septal separation angle determined from planar scanning. This creates a further planar dataset denoted 'reprojected P-RNV' (rP-RNV) giving a reprojected ejection fraction (EFR) which can be used as a validation variable in transitioning to SPECT-only acquisition. Performing t tests showed no statistical difference between EFP and EFR (P > .017) but bias was observed in EFS results compared to EFP and EFS compared to EFR results. An unblinded, comparison of parametric data between the three datasets for a subset of ten patients showed good clinical concordance. False negative and false positive rates were low for rP-RNV compared to P-RNV. The reprojected planar LVEF correlates well to P-RNV EF values. The rP-RNV dataset can aid clinicians in transitioning from planar RNV to SPECT-only acquisition.

  2. Automated segmentation and registration technique for HMPAO-SPECT imaging of Alzheimer's patients

    NASA Astrophysics Data System (ADS)

    Radau, Perry E.; Slomka, Piotr J.; Julin, Per; Svensson, Leif; Wahlund, Lars-Olof

    2000-06-01

    We present an operator-independent software technique for segmentation, realignment and analysis of brain perfusion images, with both voxel-wise and regional quantitation methods. Inter-subject registration with normalized mutual information was tested with simulated defects. Brain perfusion images (HMPAO-SPECT) from 56 subjects (21 AD; 35 controls) were retrospectively analyzed. Templates were created from the 3-D registration of the controls. Automatic segmentation was developed to remove extraneous activity that disrupts registration. Two new registration methods, robust least squares (RLS) and normalized mutual information (NMI) were implemented and compared with sum of absolute differences (CD). The automatic segmentation method caused a registration displacement of 0.4 +/- 0.3 pixels compared with manual segmentation. NMI registration proved to be less adversely effected by simulated defects than RLS or CD. The error in quantitating the patient-template parietal ratio due to mis- registration was 2.0% and 0.5% for 70% and 85% hypoperfusion defects, respectively. The registration processing time was 1.6 min (233 MHz Pentium). The most accurate discriminant utilized a logistic equation parameterized by mean counts of the parietal and temporal regions of the map, (91 +/- 8% Se, 97 +/- 5% Sp). BRASS is a fast, objective software package for single-step analysis of brain SPECT, suitable to aid diagnosis of AD.

  3. Clinical evaluation of 360 degrees and 180 degrees data sampling techniques for transaxial SPECT thallium-201 myocardial perfusion imaging.

    PubMed

    Go, R T; MacIntyre, W J; Houser, T S; Pantoja, M; O'Donnell, J K; Feiglin, D H; Sufka, B J; Underwood, D A; Meaney, T F

    1985-07-01

    The most serious controversy regarding the application of transaxial SPECT technology to 201Tl myocardial perfusion imaging is the choice between 360 degrees compared with 180 degrees data sampling techniques. The present study utilized the original 360 degrees sampled raw data of 25 patients who had both SPECT 201Tl myocardial perfusion imaging and coronary angio/ventriculography for back projection reprocessing to accomplish the 360 degrees/180 degrees comparison. The results show a high incidence, 36% (9/25), of false-positive segmental perfusion abnormality and a high incidence, 24% (6/25), of moderate to severe degree of image distortion with the 180 degrees data sampled reconstructed images. These were not observed in the 360 degrees data sampled reconstructed images. The above findings confirmed our previous preliminary conclusion that even though the 180 degrees data sampling technique has the advantage of providing improved image contrast and reduction in acquisition time it is not a reliable technique and should be abandoned. The 360 degrees data sampling is the technique of choice for transaxial SPECT 201Tl myocardial perfusion imaging.

  4. Effect of power Doppler and digital subtraction techniques on the comparison of myocardial contrast echocardiography with SPECT.

    PubMed

    Haluska, B; Case, C; Short, L; Anderson, J; Marwick, T H

    2001-05-01

    To compare the accuracy and feasibility of harmonic power Doppler and digitally subtracted colour coded grey scale imaging for the assessment of perfusion defect severity by single photon emission computed tomography (SPECT) in an unselected group of patients. Cohort study. Regional cardiothoracic unit. 49 patients (mean (SD) age 61 (11) years; 27 women, 22 men) with known or suspected coronary artery disease were studied with simultaneous myocardial contrast echo (MCE) and SPECT after standard dipyridamole stress. Regional myocardial perfusion by SPECT, performed with (99m)Tc tetrafosmin, scored qualitatively and also quantitated as per cent maximum activity. Normal perfusion was identified by SPECT in 225 of 270 segments (83%). Contrast echo images were interpretable in 92% of patients. The proportion of normal MCE by grey scale, subtracted, and power Doppler techniques were respectively 76%, 74%, and 88% (p < 0.05) at > 80% of maximum counts, compared with 65%, 69%, and 61% at < 60% of maximum counts. For each technique, specificity was lowest in the lateral wall, although power Doppler was the least affected. Grey scale and subtraction techniques were least accurate in the septal wall, but power Doppler showed particular problems in the apex. On a per patient analysis, the sensitivity was 67%, 75%, and 83% for detection of coronary artery disease using grey scale, colour coded, and power Doppler, respectively, with a significant difference between power Doppler and grey scale only (p < 0.05). Specificity was also the highest for power Doppler, at 55%, but not significantly different from subtracted colour coded images. Myocardial contrast echo using harmonic power Doppler has greater accuracy than with grey scale imaging and digital subtraction. However, power Doppler appears to be less sensitive for mild perfusion defects.

  5. Development and evaluation of a new fully automatic motion detection and correction technique in cardiac SPECT imaging.

    PubMed

    Bai, Chuanyong; Maddahi, Jamshid; Kindem, Joel; Conwell, Richard; Gurley, Michael; Old, Rex

    2009-01-01

    In cardiac SPECT perfusion imaging, motion correction of the data is critical to the minimization of motion introduced artifacts in the reconstructed images. Software-based (data-driven) motion correction techniques are the most convenient and economical approaches to fulfill this purpose. However, the accuracy is significantly affected by how the data complexities, such as activity overlap, non-uniform tissue attenuation, and noise are handled. We developed STASYS, a new, fully automatic technique, for motion detection and correction in cardiac SPECT. We evaluated the performance of STASYS by comparing its effectiveness of motion correcting patient studies with the current industry standard software (Cedars-Sinai MoCo) through blind readings by two readers independently. For 204 patient studies from multiple clinical sites, the first reader identified (1) 69 studies with medium to large axial motion, of which STASYS perfectly or significantly corrected 86.9% and MoCo 72.5%; and (2) 20 studies with medium to large lateral motion, of which STASYS perfectly or significantly corrected 80.0% and MoCo 60.0%. The second reader identified (1) 84 studies with medium to large axial motion, of which STASYS perfectly or significantly corrected 82.2% and MoCo 76.2%; and (2) 34 studies with medium to large lateral motion, of which STASYS perfectly or significantly corrected 58.9% and MoCo 50.0%. We developed a fully automatic software-based motion correction technique, STASYS, for cardiac SPECT. Clinical studies showed that STASYS was effective and corrected a larger percent of cardiac SPECT studies than the current industrial standard software.

  6. Recent advances in SPECT

    SciTech Connect

    Tsui, Benjamin M. W.

    1998-08-28

    Single photon emission computed tomography (SPECT) is a medical imaging modality that combines conventional nuclear medicine imaging technique and methods of computed tomography (CT). From images that represent the biodistribution of the injected radiopharmaceutical in the patient, SPECT provides functional information that is unique. The first SPECT system was developed in the sixties. However, early progress of SPECT was hampered by the lack of adequate image reconstruction methods. The development of x-ray CT and image reconstruction methods in the seventies spurred a renewed interest in SPECT. In 1981, the first commercial SPECT system based on a single rotating camera was available for clinical use. Today, most modern SPECT systems consist of multiple cameras that rotate around the patients. They have better spatial resolution and higher detection efficiency as compared to the earlier single camera systems. Recently, a new generation of dual camera systems allowing for coincidence imaging of positron emitting radiopharmaceuticals has emerged in the commercial market. Additionally, new quantitative image reconstruction methods are under development. They compensate for image degrading factors including attenuation, collimator-detector blurring and scatter. Also, they result in SPECT images with improved image quality and more accurately represent the three-dimensional radioactivity distribution in the patient. Such advances in radiopharmaceuticals, instrumentation, image reconstruction, compensation methods, and clinical applications have fueled a steady growth of SPECT as an important diagnostic tool in patient management.

  7. SPECT radiopharmaceuticals for dementia.

    PubMed

    Guidotti, Claudio; Farioli, Daniela; Gaeta, Maria Chiara; Giovannini, Elisabetta; Lazzeri, Patrizia; Meniconi, Martina; Ciarmiello, Andrea

    2013-12-01

    Over the last decade the interest towards functional neuroimaging has gradually increased, especially in the field of neurodegenerative diseases. At present, diagnosis of dementia is mostly clinical. Numerous modalities of neuroimaging are today available, each of them allowing a different aspect of neurodegeneration to be investigated. Although during the last period many have predicted a forthcoming disappearance of SPECT imaging in favour of the PET imaging, many new radiotracers SPECT, dual-SPECT tracers techniques and receptor targeting designed radiopharmaceuticals are currently at study. Besides, last decade has also assisted to the development of new SPECT imaging systems, most of them integrated with other imaging modalities (MRI, CT, ultrasound techniques), granting improved imaging capabilities. All these improved conditions, especially appealing for the neuroimaging, together with the new radiopharmaceuticals in development may renovate the interest for SPECT clinical applications.

  8. Standardization of techniques for using single-photon emission computed tomography (SPECT) for aerosol deposition assessment of orally inhaled products.

    PubMed

    Fleming, John; Bailey, Dale L; Chan, Hak-Kim; Conway, Joy; Kuehl, Philip J; Laube, Beth L; Newman, Stephen

    2012-12-01

    Single-photon emission computed tomography (SPECT) can be used to measure the three-dimensional (3D) distribution of inhaled aerosol deposition in the lungs. This is of value in evaluating and optimizing drug delivery by inhalation. 3D imaging has the advantage over planar scintigraphy of giving better data on the distribution of deposition within the lung. There are a variety of different methods of acquisition and analysis of the data, which makes interpretation of results difficult to compare between centers. This article describes a standardized protocol that aims to overcome this problem. Although not being completely prescriptive, it presents the key recommendations that are necessary to ensure consistency. In addition to radiolabel validation, these are (i) having some form of accountability of the activity measurements as quality control, (ii) producing quantitative images by performing attenuation and preferably scatter correction, (iii) defining volumes of interest and calculating parameters in the manner described, and (iv) describing in any report the details of technique used. When carefully used, SPECT imaging is able to produce high-quality quantitative data of the 3D distribution of drug deposition within the lungs. By establishing a standardized protocol, results of 3D imaging of the deposition of orally inhaled aerosols using SPECT should be more comparable, which should enhance collaborations between centers and insure that this form of imaging becomes acceptable to the regulatory authorities.

  9. 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

  10. A three-dimensional ray-driven attenuation, scatter and geometric response correction technique for SPECT in inhomogeneous media.

    PubMed

    Laurette, I; Zeng, G L; Welch, A; Christian, P E; Gullberg, G T

    2000-11-01

    The qualitative and quantitative accuracy of SPECT images is degraded by physical factors of attenuation, Compton scatter and spatially varying collimator geometric response. This paper presents a 3D ray-tracing technique for modelling attenuation, scatter and geometric response for SPECT imaging in an inhomogeneous attenuating medium. The model is incorporated into a three-dimensional projector-backprojector and used with the maximum-likelihood expectation-maximization algorithm for reconstruction of parallel-beam data. A transmission map is used to define the inhomogeneous attenuating and scattering object being imaged. The attenuation map defines the probability of photon attenuation between the source and the scattering site, the scattering angle at the scattering site and the probability of attenuation of the scattered photon between the scattering site and the detector. The probability of a photon being scattered through a given angle and being detected in the emission energy window is approximated using a Gaussian function. The parameters of this Gaussian function are determined using physical measurements of parallel-beam scatter line spread functions from a non-uniformly attenuating phantom. The 3D ray-tracing scatter projector-backprojector produces the scatter and primary components. Then, a 3D ray-tracing projector-backprojector is used to model the geometric response of the collimator. From Monte Carlo and physical phantom experiments, it is shown that the best results are obtained by simultaneously correcting attenuation, scatter and geometric response, compared with results obtained with only one or two of the three corrections. It is also shown that a 3D scatter model is more accurate than a 2D model. A transmission map is useful for obtaining measurements of attenuation and scatter in SPECT data, which can be used together with a model of the geometric response of the collimator to obtain corrected images with quantitative and diagnostically

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

    SciTech Connect

    Krengli, Marco . E-mail: krengli@med.unipmn.it; Ballare, Andrea; Cannillo, Barbara; Rudoni, Marco; Kocjancic, Ervin; Loi, Gianfranco; Brambilla, Marco; Inglese, Eugenio; Frea, Bruno

    2006-11-15

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

  12. 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

  13. Quantitative myocardial perfusion SPECT.

    PubMed

    Tsui, B M; Frey, E C; LaCroix, K J; Lalush, D S; McCartney, W H; King, M A; Gullberg, G T

    1998-01-01

    In recent years, there has been much interest in the clinical application of attenuation compensation to myocardial perfusion single photon emission computed tomography (SPECT) with the promise that accurate quantitative images can be obtained to improve clinical diagnoses. The different attenuation compensation methods that are available create confusion and some misconceptions. Also, attenuation-compensated images reveal other image-degrading effects including collimator-detector blurring and scatter that are not apparent in uncompensated images. This article presents basic concepts of the major factors that degrade the quality and quantitative accuracy of myocardial perfusion SPECT images, and includes a discussion of the various image reconstruction and compensation methods and misconceptions and pitfalls in implementation. The differences between the various compensation methods and their performance are demonstrated. Particular emphasis is directed to an approach that promises to provide quantitative myocardial perfusion SPECT images by accurately compensating for the 3-dimensional (3-D) attenuation, collimator-detector response, and scatter effects. With advances in the computer hardware and optimized implementation techniques, quantitatively accurate and high-quality myocardial perfusion SPECT images can be obtained in clinically acceptable processing time. Examples from simulation, phantom, and patient studies are used to demonstrate the various aspects of the investigation. We conclude that quantitative myocardial perfusion SPECT, which holds great promise to improve clinical diagnosis, is an achievable goal in the near future.

  14. Comparison of xenon enhanced CT (XeCT) and I-123 iodoamphetamine (SPECT/IMP) techniques for measurement of regional cerebral blood flow (rCBF)

    SciTech Connect

    Hellman, R.S.; Collier, B.D.; Kilgor, D.P.; Walsh, P.R.; Daniels, D.L.; Haughton, V.M.; Williams, A.L.; Pojunas, K.W.; Tikofsky, R.S.; Isitman, A.T.

    1985-05-01

    An ongoing prospective study measuring rCBF by XeCT(20 patients) and SPECT/IMP (84 patients) to date includes 9 patients examined by both techniques. XeCT was done as 3 contiguous transaxial tomograms using a scanner (GE 9800) equipped with dynamic imaging capability and a gas delivery system for inspiring 30% Xenon. SPECT/IMP was done 20 minutes after injection of 3-5 mCi of IMP, obtaining 64 views over 360 degrees, 40 sec./view, with either a GE 400T or 400ACT. SPECT/IMP images obtained with the 400ACT camera (specially designed for head work) were superior to those obtained with the older camera. For all 9 cases, both techniques demonstrated flow abnormalities at all sites of infarction identified by conventional CT (TCT): 1 patient with normal TCT also had normal rCBF examinations. Furthermore, 8 of 9 cases showed evidence of ischemia (regions with normal TCT and abnormal rCBF measurements) by both techniques.

  15. Adaptive SPECT

    PubMed Central

    Barrett, Harrison H.; Furenlid, Lars R.; Freed, Melanie; Hesterman, Jacob Y.; Kupinski, Matthew A.; Clarkson, Eric; Whitaker, Meredith K.

    2008-01-01

    Adaptive imaging systems alter their data-acquisition configuration or protocol in response to the image information received. An adaptive pinhole single-photon emission computed tomography (SPECT) system might acquire an initial scout image to obtain preliminary information about the radiotracer distribution and then adjust the configuration or sizes of the pinholes, the magnifications, or the projection angles in order to improve performance. This paper briefly describes two small-animal SPECT systems that allow this flexibility and then presents a framework for evaluating adaptive systems in general, and adaptive SPECT systems in particular. The evaluation is in terms of the performance of linear observers on detection or estimation tasks. Expressions are derived for the ideal linear (Hotelling) observer and the ideal linear (Wiener) estimator with adaptive imaging. Detailed expressions for the performance figures of merit are given, and possible adaptation rules are discussed. PMID:18541485

  16. Blood oxygen level-dependent (BOLD) MRI: A novel technique for the assessment of myocardial ischemia as identified by nuclear imaging SPECT.

    PubMed

    Egred, M; Waiter, G D; Redpath, T W; Semple, S K I; Al-Mohammad, A; Walton, S

    2007-12-01

    The different levels of deoxyhemoglobin in the ischemic myocardium, induced by stressors such as dipyridamole, can be detected by blood oxygen level-dependent (BOLD) MRI and may be used to diagnose myocardial ischemia. The aim of this study was to assess the signal change in the myocardium on BOLD MRI as well as wall thickening between rest and dipyridamole stress images in ischemic and non-ischemic myocardium as identified on SPECT imaging. Twelve patients with stress-induced myocardial ischemia on SPECT underwent rest and dipyridamole stress MRI using a double breath-hold, T2()-weighted, ECG-gated sequence to produce BOLD contrast images as well as cine-MRI for wall thickening assessment in 10 of the 12 patients. Signal change on BOLD MRI and wall thickening were compared between rest and stress images in ischemic and non-ischemic myocardial segments as identified on SPECT. In each patient, two MRI slices containing 16 segments per slice were analysed. In total, there were 384 segments for BOLD analysis and 320 for wall thickening. For BOLD signal 137 segments correlated to segments with reversible ischemia on SPECT and 247 to normal segments, while for wall thickening 112 segments correlated to segments with reversible ischemia and 208 to normal segments. The average BOLD MRI signal intensity change was -13.8 (+/-16.3)% in the ischemic segments compared to -10.3 (+/-14.7)% in the non-ischemic segments (p=0.05). The average wall thickening was 6.4 (+/-3.4) mm in the ischemic segments compared to 8.7 (+/-3.8) mm in the non-ischemic segments (p<0.0001). Stress-induced ischemic myocardium has a different signal change and wall thickening than non-ischemic myocardium and may be differentiated on BOLD MRI. Larger studies are needed to define a threshold for detection and to determine the sensitivity and specificity of this technique.

  17. Local and Non-local Regularization Techniques in Emission (PET/SPECT) Tomographic Image Reconstruction Methods.

    PubMed

    Ahmad, Munir; Shahzad, Tasawar; Masood, Khalid; Rashid, Khalid; Tanveer, Muhammad; Iqbal, Rabail; Hussain, Nasir; Shahid, Abubakar; Fazal-E-Aleem

    2016-06-01

    Emission tomographic image reconstruction is an ill-posed problem due to limited and noisy data and various image-degrading effects affecting the data and leads to noisy reconstructions. Explicit regularization, through iterative reconstruction methods, is considered better to compensate for reconstruction-based noise. Local smoothing and edge-preserving regularization methods can reduce reconstruction-based noise. However, these methods produce overly smoothed images or blocky artefacts in the final image because they can only exploit local image properties. Recently, non-local regularization techniques have been introduced, to overcome these problems, by incorporating geometrical global continuity and connectivity present in the objective image. These techniques can overcome drawbacks of local regularization methods; however, they also have certain limitations, such as choice of the regularization function, neighbourhood size or calibration of several empirical parameters involved. This work compares different local and non-local regularization techniques used in emission tomographic imaging in general and emission computed tomography in specific for improved quality of the resultant images.

  18. Evaluation of reconstruction techniques in regional cerebral blood flow SPECT using trade-off plots: a Monte Carlo study.

    PubMed

    Olsson, Anna; Arlig, Asa; Carlsson, Gudrun Alm; Gustafsson, Agnetha

    2007-09-01

    The image quality of single photon emission computed tomography (SPECT) depends on the reconstruction algorithm used. The purpose of the present study was to evaluate parameters in ordered subset expectation maximization (OSEM) and to compare systematically with filtered back-projection (FBP) for reconstruction of regional cerebral blood flow (rCBF) SPECT, incorporating attenuation and scatter correction. The evaluation was based on the trade-off between contrast recovery and statistical noise using different sizes of subsets, number of iterations and filter parameters. Monte Carlo simulated SPECT studies of a digital human brain phantom were used. The contrast recovery was calculated as measured contrast divided by true contrast. Statistical noise in the reconstructed images was calculated as the coefficient of variation in pixel values. A constant contrast level was reached above 195 equivalent maximum likelihood expectation maximization iterations. The choice of subset size was not crucial as long as there were > or = 2 projections per subset. The OSEM reconstruction was found to give 5-14% higher contrast recovery than FBP for all clinically relevant noise levels in rCBF SPECT. The Butterworth filter, power 6, achieved the highest stable contrast recovery level at all clinically relevant noise levels. The cut-off frequency should be chosen according to the noise level accepted in the image. Trade-off plots are shown to be a practical way of deciding the number of iterations and subset size for the OSEM reconstruction and can be used for other examination types in nuclear medicine.

  19. A technique using {sup 99m}Tc-mebrofenin SPECT for radiotherapy treatment planning for liver cancers or metastases

    SciTech Connect

    Shen, Sui; Jacob, Rojymon; Bender, Luvenia W.; Duan, Jun; Spencer, Sharon A.

    2014-04-01

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

  20. A technique using 99mTc-mebrofenin SPECT for radiotherapy treatment planning for liver cancers or metastases.

    PubMed

    Shen, Sui; Jacob, Rojymon; Bender, Luvenia W; Duan, Jun; Spencer, Sharon A

    2014-01-01

    Radiotherapy or stereotactic body radiosurgery (SBRT) requires a sufficient functional liver volume to tolerate the treatment. The current study extended the work of de Graaf et al. (2010) [3] on the use of (99m)Tc-mebrofenin imaging for presurgery planning to radiotherapy planning for liver cancer or metastases. Patient was immobilized and imaged in an identical position on a single-photon emission computed tomography/computed tomography (SPECT-CT) system and a radiotherapy simulation CT system. (99m)Tc-mebrofenin SPECT was registered to the planning CT through image registration of noncontrast CT from SPECT-CT system to the radiotherapy planning CT. The voxels with higher uptake of (99m)Tc-mebrofenin were transferred to the planning CT as an avoidance structure in optimizing a 2-arc RapidArc plan for SBRT delivery. Excellent dose coverage to the target and sparing of the healthy remnant liver volume was achieved. This report illustrated a procedure for the use of (99m)Tc-mebrofenin SPECT for optimizing radiotherapy for liver cancers and metastases. Copyright © 2014 American Association of Medical Dosimetrists. All rights reserved.

  1. SPECT/CT in imaging foot and ankle pathology-the demise of other coregistration techniques.

    PubMed

    Mohan, Hosahalli K; Gnanasegaran, Gopinath; Vijayanathan, Sanjay; Fogelman, Ignac

    2010-01-01

    Disorders of the ankle and foot are common and given the complex anatomy and function of the foot, they present a significant clinical challenge. Imaging plays a crucial role in the management of these patients, with multiple imaging options available to the clinician. The American College of radiology has set the appropriateness criteria for the use of the available investigating modalities in the management of foot and ankle pathologies. These are broadly classified into anatomical and functional imaging modalities. Recently, single-photon emission computed tomography and/or computed tomography scanners, which can elegantly combine functional and anatomical images have been introduced, promising an exciting and important development. This review describes our clinical experience with single-photon emission computed tomography and/or computed tomography and discusses potential applications of these techniques.

  2. SPECT in the diagnosis of hepatic hemangioma

    SciTech Connect

    Brunetti, J.C.; Van Heertum, R.L.; Yudd, A.P.

    1985-05-01

    Tc99m labeled red blood cell blood flow and delayed static blood pool imaging is widely accepted as a reliable, accurate method for the diagnosis of hepatic hemangiomata. The purpose of this study is to assess the relative value of SPECT blood pool imaging in the evaluation of hepatic hemangionata. A total of 68 patients, including 21 patients with proven hepatic cavernous hemangiomas, were studied using both planar and SPECT imaging techniques. All patients underwent multi-phase evaluation which included a hepatic flow study, immediate planar images of the liver, followed by a 360/sup 0/ tomographic (SPECT) study and subsequent 60 minute delayed static planar hepatic blood pool images. All 21 patients with proven hepatic hemangiomas had a positive SPECT exam and 17 of the 21 (81%) patients had a positive planar exam. In the 21 patients, there were a total of 36 hemangiomas ranging in size from .7 cm to 13 cm. The SPECT imaging technique correctly identified all 36 lesions (100%) where as planar imaging detected 25 of the 36 lesions (69.4%). In all the remaining patients (10-normal, 17-metastatic disease, 12-hepatocellular disease, 6-hepatoma, 2-liver cysts), both the planar and SPECT imaging techniques were interpreted as showing no evidence of focal sequestration of red blood cells. SPECT hepatic blood pool imaging represents an improvement in the evaluation of hepatic hemangioma as a result of a reduction in imaging time (less than thirty minutes), improved spatial resolution and greater overall accuracy.

  3. NOTE: Comparison of correction techniques for simultaneous 201Tl/99mTc myocardial perfusion SPECT imaging: a dog study

    NASA Astrophysics Data System (ADS)

    Knesaurek, Karin; Machac, Josef

    2000-11-01

    We compared two correction methods for simultaneous 201Tl/99mTc dual-isotope single-photon emission computed tomography (SPECT). Both approaches use the information from the third energy window placed between the photopeak windows of the 201Tl and 99mTc. The first approach, described by Moore et al, corrects only for the contribution of the 99mTc to the 201Tl primary 70 keV window. We developed the three-window transformation dual-isotope correction method, which is a simultaneous cross-talk correction. The two correction methods were compared in a simultaneous 201Tl/99mTc sestamibi cardiac dog study. Three separate acquisitions were performed in this dog study: two single-isotope and one dual-isotope acquisition. The 201Tl single-isotope images were used as references. The total number of counts, and the contrast between the left ventricular cavity (LVC) and the myocardium, were used in 70 keV short-axis slices as parameters for evaluating the results of the dual-isotope correction methods. Three consecutive short-axis slices were used to calculate averaged contrast and the averaged total number of counts. The total number of the counts was 667 000 ± 500 and 414 500 ± 400 counts for the dual-isotope (201Tl + 99mTc) and single-isotope (201Tl-only) 70 keV images, respectively. The corrected dual-isotope images had 514 700 ± 700 and 368 000 ± 600 counts for Moore's correction and our approach, respectively. Moore's method improved contrast in the dual-isotope 70 keV image to 0.14 ± 0.03 from 0.11 ± 0.02, which was the value in the 70 keV non-corrected dual-isotope image. Our method improved the same contrast to 0.22 ± 0.03. The contrast in the 201Tl single-isotope 70 keV image was 0.28 ± 0.02. Both methods improved the 70 keV dual-isotope images. However, our approach provided slightly better images than Moore's correction when compared with 201Tl-only 70 keV images.

  4. [A technique for a rapid imaging of regional CBF and partition coefficient using dynamic SPECT and N-isopropyl-p-[123I]iodoamphetamine (123I-IMP)].

    PubMed

    Itoh, H; Iida, H; Murakami, M; Bloomfield, P M; Miura, S; Okudera, T; Inugami, A; Ogawa, T; Hatazawa, J; Fujita, H

    1993-01-01

    IMP is a flow tracer due to a large first pass extraction fraction and high affinity in the brain, but significant clearance from the brain causes change of distribution when the scan start time is delayed. The purpose of the present study is to develop a new method to rapidly calculate a quantitative CBF image by taking into account for the clearance effects. A dynamic SPECT scan was performed on 5 subjects (4 patients with cerebral infarction and 1 normal volunteer) following slow intravenous infusion of 123I-IMP. The arterial input function was obtained by frequent blood sampling and by measuring an octanol extraction ratio for each sample. Firstly, non-linear least square fitting (NLS) was performed to investigate the tracer kinetics of 123I-IMP. The 3 compartment model analysis yielded negligibly small k3 (retaining rate constant) (0.0056 +/- 0.0128 (ml/ml/min)), and consistent k1 (transport rate constant) with those determined by 2 compartment model (2CM) analysis (r = 0.96, p < 0.001). In addition, k1 was consistent with CBF measured by 15O water PET technique. These observations suggested validity of using 2CM for describing the IMP tracer kinetics. Secondly, a weighted integration (WI) technique has been implemented to calculate rapidly images of CBF and partition coefficient (Vd). The WI technique yielded values of CBF (k1) and Vd (k1/k2). They were confirmed to be consistent with those determined by NLS technique (CBF; r = 0.99, p < 0.001, Vd; r = 0.99, p < 0.001), and calculated k1 agreed well with PET CBF (r = 0.91, p < 0.001). We observed changed Vd in infarcted patients. This supports an importance for calculating of Vd image. Vd image will provide additional clinical information because 123I-IMP binding mechanism may be related to cell viability.

  5. Single photon emission computed tomography (SPECT) in epilepsy

    SciTech Connect

    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 promoted 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.

  6. SPECT (single photon emission computed tomography) in pediatrics.

    PubMed

    Chiron, Catherine

    2013-01-01

    Surgery of focal epilepsies in childhood has largely benefited from the recent advances of the noninvasive functional imaging techniques, particularly SPECT which presurgically contributes to the localization of the seizure onset zone, in order to select the patients, decide the optimal placement of intracranial electrodes, and plan the resection. Peri-ictal SPECT (ictal and postictal) proved especially useful when video-EEG is not contributory, when MRI looks normal or shows multiple abnormalities, or in cases of discrepant findings within the presurgery workup. Because of a poor temporal resolution, peri-ictal SPECT must be coupled with video-EEG. Multimodal imaging so-called SISCOM (peri-ictal - interictal SPECT subtraction image superimposed on MRI) increases the sensitivity of peri-ictal SPECT by about 70% and makes it a good predictor of seizure-free outcome after surgery. In addition, interictal SPECT occasionally provides some interesting results regarding functional cortical maturation and learning disorders in childhood.

  7. I-123 Iofetamine SPECT scan in children with neurological disorders

    SciTech Connect

    Flamini, J.R.; Konkol, R.J.; Wells, R.G.; Sty, J.R. )

    1990-10-01

    I-123 Iofetamine (IMP) single photon emission computed tomography (SPECT) imaging of the brain in 42 patients (ages 14 days to 23 years) was compared with other localizing studies in children with neurological diseases. All had an EEG and at least one imaging study of the brain (computed tomography (CT) or magnetic resonance imaging (MRI), or both). Seventy-eight percent of the patients had an EEG within 24-72 hours of the IMP-SPECT scan. Thirty-five (83%) had a history of seizures, and the remainder had other neurological conditions without a history of seizures. In most cases, a normal EEG reading with normal CT or MRI result predicted a normal SPECT study. When the EEG was abnormal the majority of the IMP-SPECT scans were abnormal and localized the abnormality to the same region. A comparison with CT and MRI showed that structural abnormalities involving the cortex were usually well demonstrated with IMP-SPECT imaging. Structural lesions confined to the white matter were generally not detectable with IMP-SPECT. In a few cases, SPECT scans revealed abnormalities in deep brain areas not identified by EEG. IMP-SPECT imaging is a valuable technique for the detection and localization of abnormal cerebral metabolic activity in children with seizure disorders. A correlation with CT or MRI is essential for proper interpretation of abnormalities detected with IMP SPECT imaging.

  8. Assessment of cardiac function using myocardial perfusion imaging technique on SPECT with 99mTc sestamibi

    NASA Astrophysics Data System (ADS)

    Gani, M. R. A.; Nazir, F.; Pawiro, S. A.; Soejoko, D. S.

    2016-03-01

    Suspicion on coronary heart disease can be confirmed by observing the function of left ventricle cardiac muscle with Myocardial Perfusion Imaging techniques. The function perfusion itself is indicated by the uptake of radiopharmaceutical tracer. The 31 patients were studied undergoing the MPI examination on Gatot Soebroto Hospital using 99mTc-sestamibi radiopharmaceutical with stress and rest conditions. Stress was stimulated by physical exercise or pharmacological agent. After two hours, the patient did rest condition on the same day. The difference of uptake percentage between stress and rest conditions will be used to determine the malfunction of perfusion due to ischemic or infarct. Degradation of cardiac function was determined based on the image-based assessment of five segments of left ventricle cardiac. As a result, 8 (25.8%) patients had normal myocardial perfusion and 11 (35.5%) patients suspected for having partial ischemia. Total ischemia occurred to 8 (25.8%) patients with reversible and irreversible ischemia and the remaining 4 (12.9%) patients for partial infarct with characteristic the percentage of perfusion ≤50%. It is concluded that MPI technique of image-based assessment on uptake percentage difference between stress and rest conditions can be employed to predict abnormal perfusion as complementary information to diagnose the cardiac function.

  9. Neuroreceptor imaging with SPECT.

    PubMed

    Innis, R B

    1992-11-01

    Single photon emission computed tomography (SPECT) imaging can provide useful measurements of brain receptors and endogenous neurotransmitters and may have significant experimental and clinical applications. This presentation reviews the use of SPECT for neuroreceptor imaging. Studies of receptors for benzodiazepines, dopamine D2 agents, and dopamine reuptake sites will be used to exemplify the capabilities of SPECT. Tracers labeled with the radioisotope 125I have high affinity, high brain uptake, and high ratios of specific to nonspecific binding. Imaging studies of human and nonhuman primate brain will be presented, and the potential clinical applicability of these agents will be discussed.

  10. 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.

  11. Abdominal SPECT imaging

    SciTech Connect

    Van Heertum, R.L.; Brunetti, J.C.; Yudd, A.P.

    1987-07-01

    Over the past several years, abdominal single photon emission computed tomography (SPECT) imaging has evolved from a research tool to an important clinical imaging modality that is helpful in the diagnostic assessment of a wide variety of disorders involving the abdominal viscera. Although liver-spleen imaging is the most popular of the abdominal SPECT procedures, blood pool imaging is becoming much more widely utilized for the evaluation of cavernous hemangiomas of the liver as well as other vascular abnormalities in the abdomen. Adjunctive indium leukocyte and gallium SPECT studies are also proving to be of value in the assessment of a variety of infectious and neoplastic diseases. As more experience is acquired in this area, SPECT should become the primary imaging modality for both gallium and indium white blood cells in many institutions. Renal SPECT, on the other hand, has only recently been used as a clinical imaging modality for the assessment of such parameters as renal depth and volume. The exact role of renal SPECT as a clinical tool is, therefore, yet to be determined. 79 references.

  12. Ineffectiveness of dipyridamole SPECT thallium imaging as a screening technique for coronary artery disease in patients with end-stage renal failure

    SciTech Connect

    Marwick, T.H.; Steinmuller, D.R.; Underwood, D.A.; Hobbs, R.E.; Go, R.T.; Swift, C.; Braun, W.E. )

    1990-01-01

    The efficacy of dipyridamole single photon emission computed tomography (SPECT) thallium as a screening test for coronary artery disease (CAD), was studied in 45 patients with end-stage renal failure undergoing evaluation for renal transplantation. Coronary arteriography, dipyridamole SPECT thallium imaging and clinical follow-up were performed in all patients. Nineteen patients (42%) had an obstruction of 50% or more in at least one coronary artery. Fourteen patients had a positive thallium scan, but 7 of these were false-positives (sensitivity 37%, specificity 73%). The sensitivity was considerably lower than that quoted for non-ESRF patients in the literature, and significantly lower than a control group of 19 patients without ESRF having comparable severity and distribution of CAD. Five of the 6 patients who died of cardiac causes over a mean follow-up period of 25 months had normal thallium imaging, but all had significant coronary artery disease at cardiac catheterization. Dipyridamole SPECT thallium imaging has not proved a useful screening test for angiographically significant CAD, and does not predict cardiac prognosis in this population.

  13. Rodent brain imaging with SPECT/CT

    SciTech Connect

    Seo, Youngho; Gao, D.-W.; Hasegawa, Bruce H.; Dae, Michael W.; Franc, Benjamin L.

    2007-04-15

    We evaluated methods of imaging rat models of stroke in vivo using a single photon emission computed tomography (SPECT) system dedicated to small animal imaging (X-SPECT{sup TM}, Gamma Medica-Ideas, Northridge, CA). An animal model of ischemic stroke was developed for in vivo SPECT/CT imaging using the middle cerebral artery occlusion (MCAO) technique. The presence of cerebral ischemia was verified in ex vivo studies using triphenyltetrazolium chloride (TTC) staining. In vivo radionuclide imaging of cerebral blood flow was performed in rats following MCAO using dynamic planar imaging of {sup 99m}Tc-exametazime with parallel hole collimation. This was followed immediately by in vivo radionuclide imaging of cerebral blood flow with {sup 99m}Tc-exametazime in the same animals using 1-mm pinhole SPECT. Correlated computed tomography imaging was performed to localize radiopharmaceutical uptake. The animals were allowed to recover and ex vivo autoradiography was performed with separate administration of {sup 99m}Tc-exametazime. Time activity curve of {sup 99m}Tc-exametazime showed that the radiopharmaceutical uptake could be maintained for over 9 min. The activity would be expected to be relatively stable for a much longer period, although the data were only obtained for 9 min. TTC staining revealed sizable infarcts by visual observation of inexistence of TTC stain in infracted tissues of MCAO rat brains. In vivo SPECT imaging showed cerebral blood flow deficit in the MCAO model, and the in vivo imaging result was confirmed with ex vivo autoradiography. We have demonstrated a capability of imaging regions of cerebral blood flow deficit in MCAO rat brains in vivo using a pinhole SPECT dedicated to small animal imaging.

  14. Improved diagnostic accuracy of lung perfusion imaging using Tc-99m MAA SPECT

    SciTech Connect

    O'Donnell, J.K.; Golish, J.A.; Go, R.T.; Risius, B.; Graor, R.A.; MacIntyre, W.J.; Feiglin, D.H.

    1984-01-01

    The addition of emission tomography (SPECT) to pulmonary perfusion imaging should improve diagnostic accuracy by detecting perfusion defects otherwise masked by superimposition of normal lung activity and by reducing problems with interpretation of defects that result from overlying soft tissue or pleural effusions. In order to examine the contribution of SPECT in the scintigraphic evaluation for pulmonary embolus (PE), the authors have obtained both planar and SPECT studies in 94 cases of suspected PE. All studies employed 3-4 mCi of Tc-99m MAA and standard six-view planar image acquisition. SPECT raw data of 64 images were then acquired over a 360 degree transaxial rotation with subsequent computer reconstruction. Xe-133 ventilation studies were performed when clinically indicated and tolerated by the patient. For 19 studies angiographic (AN) correlation was obtained within 24 hours. In 16/19 planar and SPECT both gave a high probability of PE but SPECT gave better segmental localization and showed better agreement with the number of defects seen at AN. In 3 indeterminate planar scans, 2 were low probability with SPECT and had negative AN. The third, a patient with Wegener's vasculitis, remained indeterminate with SPECT and had negative AN. Five patients with PE had repeat planar/SPECT/AN studies to evaluate response to treatment. SPECT correlated better with AN findings in each case. The authors conclude that SPECT perfusion imaging provides better anatomic accuracy for defects representing PE and is the non-invasive technique of choice for documenting response to therapy.

  15. PET and SPECT imaging in veterinary medicine.

    PubMed

    LeBlanc, Amy K; Peremans, Kathelijne

    2014-01-01

    Veterinarians have gained increasing access to positron emission tomography (PET and PET/CT) imaging facilities, allowing them to use this powerful molecular imaging technique for clinical and research applications. SPECT is currently being used more in Europe than in the United States and has been shown to be useful in veterinary oncology and in the evaluation of orthopedic diseases. SPECT brain perfusion and receptor imaging is used to investigate behavioral disorders in animals that have interesting similarities to human psychiatric disorders. This article provides an overview of the potential applications of PET and SPECT. The use of commercially available and investigational PET radiopharmaceuticals in the management of veterinary disease has been discussed. To date, most of the work in this field has utilized the commercially available PET tracer, (18)F-fluorodeoxyglucose for oncologic imaging. Normal biodistribution studies in several companion animal species (cats, dogs, and birds) have been published to assist in lesion detection and interpretation for veterinary radiologists and clinicians. Studies evaluating other (18)F-labeled tracers for research applications are underway at several institutions and companion animal models of human diseases are being increasingly recognized for their value in biomarker and therapy development. Although PET and SPECT technologies are in their infancy for clinical veterinary medicine, increasing access to and interest in these applications and other molecular imaging techniques has led to a greater knowledge and collective body of expertise for veterinarians worldwide. Initiation and fostering of physician-veterinarian collaborations are key components to the forward movement of this field.

  16. Proceedings of clinical SPECT (single photon emission computed tomography) symposium

    SciTech Connect

    Not Available

    1986-09-01

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

  17. [Value of (99)Tc(m)-MDP SPECT/CT in clinical decision-making for nasopharyngeal carcinoma and a comparison of the values of different imaging techniques for diagnosing skull-base bone invasion].

    PubMed

    Li, W; Zhang, R S; Zhang, L Q; Lu, B G; Fu, W H

    2017-02-23

    Objective: To analyze the clinical value of SPECT/CT in diagnosis of skull base bone invasion and clinical decision-making for nasopharyngeal carcinoma (NPC), and to compare their diagnostic value with SPECT/CT, CT, MRI, and MRI combined with SPECT (MRI-SPECT) for skull base bone invasion. Methods: Before treatment, among 348 newly diagnosed NPC patients, CT scan was performed in 186 patients (group A) and the remaining 162 patients received MRI scan (group B). Clinical doctors then made clinical management decisions according to the CT or MRI results. After that, all patients underwent (99)Tc(m)-MDP SPECT/CT examination for nasopharyngeal local tomography, and the results were provided to the clinical doctors to make clinical management decisions again. The changes between the two clinical management decisions were scored according to diagnosis, range of lesion, staging, treatment regimens, and auxiliary examination. The diagnostic value of CT scan, MRI scan, SPECT/CT and MRI-SPECT for skull base bone invasion was then evaluated and compared. Results: In terms of changes in scores of clinical management decisions, the score of group A was 1.387 and group B was 0.951, showing a significant difference between the two groups by Wilcoxon test (Z=6.570, P<0.001). By χ(2) test, there were correlations between CT and SPECT/CT (χ(2) =98.495, P<0.001), and between MRI and SPECT/CT (χ(2) =32.662, P<0.001). The consistency of CT and SPECT/CT (Kappa=0.713) was greater than MRI and SPECT (Kappa=0.449). The sensitivity of CT, MRI, SPECT/CT and MRI-SPECT was 67.1%, 84.5%, 90.8% and 100%, the specificity was 73.3%, 92.3%, 85.6% and 84.6%, and the area under the ROC curve was 0.702, 0.884, 0.882 and 0.923, respectively. Conclusions: SPECT/CT has important impact on clinical management decision for NPC. In the judgement of skull base invasion, the diagnostic value of SPECT/CT is significantly higher than CT and approximately equal to MRI. SPECT/CT should be one of the routine

  18. Added value of SPECT/CT in patients suspected of having bone infection: preliminary results.

    PubMed

    Horger, Marius; Eschmann, Susanne Martina; Pfannenberg, Christina; Storek, Dieter; Vonthein, Reinhard; Claussen, Claus D; Bares, Roland

    2007-04-01

    radiological techniques, MRI (2 x FP) and CT (2 x FN) proved equal and expectedly superior to X-ray in delivering the correct diagnosis. SPECT/CT improves the diagnostic performance of three-phase bone scan for osteomyelitis by avoiding false positive or equivocal results. An additional benefit over visual fusion of SPECT with X-ray, CT, or MRI studies could not be confirmed in our study.

  19. Monte Carlo scatter correction for SPECT

    NASA Astrophysics Data System (ADS)

    Liu, Zemei

    The goal of this dissertation is to present a quantitatively accurate and computationally fast scatter correction method that is robust and easily accessible for routine applications in SPECT imaging. A Monte Carlo based scatter estimation method is investigated and developed further. The Monte Carlo simulation program SIMIND (Simulating Medical Imaging Nuclear Detectors), was specifically developed to simulate clinical SPECT systems. The SIMIND scatter estimation (SSE) method was developed further using a multithreading technique to distribute the scatter estimation task across multiple threads running concurrently on multi-core CPU's to accelerate the scatter estimation process. An analytical collimator that ensures less noise was used during SSE. The research includes the addition to SIMIND of charge transport modeling in cadmium zinc telluride (CZT) detectors. Phenomena associated with radiation-induced charge transport including charge trapping, charge diffusion, charge sharing between neighboring detector pixels, as well as uncertainties in the detection process are addressed. Experimental measurements and simulation studies were designed for scintillation crystal based SPECT and CZT based SPECT systems to verify and evaluate the expanded SSE method. Jaszczak Deluxe and Anthropomorphic Torso Phantoms (Data Spectrum Corporation, Hillsborough, NC, USA) were used for experimental measurements and digital versions of the same phantoms employed during simulations to mimic experimental acquisitions. This study design enabled easy comparison of experimental and simulated data. The results have consistently shown that the SSE method performed similarly or better than the triple energy window (TEW) and effective scatter source estimation (ESSE) methods for experiments on all the clinical SPECT systems. The SSE method is proven to be a viable method for scatter estimation for routine clinical use.

  20. Using adaptive neuro-fuzzy inference system technique for crosstalk correction in simultaneous 99mTc/201Tl SPECT imaging: A Monte Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Heidary, Saeed; Setayeshi, Saeed

    2015-01-01

    This work presents a simulation based study by Monte Carlo which uses two adaptive neuro-fuzzy inference systems (ANFIS) for cross talk compensation of simultaneous 99mTc/201Tl dual-radioisotope SPECT imaging. We have compared two neuro-fuzzy systems based on fuzzy c-means (FCM) and subtractive (SUB) clustering. Our approach incorporates eight energy-windows image acquisition from 28 keV to 156 keV and two main photo peaks of 201Tl (77±10% keV) and 99mTc (140±10% keV). The Geant4 application in emission tomography (GATE) is used as a Monte Carlo simulator for three cylindrical and a NURBS Based Cardiac Torso (NCAT) phantom study. Three separate acquisitions including two single-isotopes and one dual isotope were performed in this study. Cross talk and scatter corrected projections are reconstructed by an iterative ordered subsets expectation maximization (OSEM) algorithm which models the non-uniform attenuation in the projection/back-projection. ANFIS-FCM/SUB structures are tuned to create three to sixteen fuzzy rules for modeling the photon cross-talk of the two radioisotopes. Applying seven to nine fuzzy rules leads to a total improvement of the contrast and the bias comparatively. It is found that there is an out performance for the ANFIS-FCM due to its acceleration and accurate results.

  1. 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

    2017-02-02

    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.

  2. Accelerated GPU based SPECT Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

    2016-06-01

    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, 111In and 131I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational efficiency

  3. 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

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

    PubMed

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

    2017-08-03

    SPECT myocardial perfusion imaging (MPI) is a clinical mainstay that is typically performed with static imaging protocols and visually or semi-quantitatively assessed for perfusion defects based upon the relative intensity of myocardial regions. Dynamic cardiac SPECT presents a new imaging technique based on time-varying information of radiotracer distribution, which permits the evaluation of regional myocardial blood flow (MBF) and coronary flow reserve (CFR). In this work, a preliminary feasibility study was conducted in a small patient sample designed to implement a unique combined static-dynamic single-dose one-day visit imaging protocol to compare quantitative dynamic SPECT with static conventional SPECT for improving the diagnosis of coronary artery disease (CAD). Fifteen patients (11 males, four females, mean age 71 ± 9 years) were enrolled for a combined dynamic and static SPECT (Infinia Hawkeye 4, GE Healthcare) imaging protocol with a single dose of (99m)Tc-tetrofosmin administered at rest and a single dose administered at stress in a one-day visit. Out of 15 patients, eleven had selective coronary angiography (SCA), 8 within 6 months and the rest within 24 months of SPECT imaging, without intervening symptoms or interventions. The extent and severity of perfusion defects in each myocardial region was graded visually. Dynamically acquired data were also used to estimate the MBF and CFR. Both visually graded images and estimated CFR were tested against SCA as a reference to evaluate the validity of the methods. Overall, conventional static SPECT was normal in ten patients and abnormal in five patients, dynamic SPECT was normal in 12 patients and abnormal in three patients, and CFR from dynamic SPECT was normal in nine patients and abnormal in six patients. Among those 11 patients with SCA, conventional SPECT was normal in 5, 3 with documented CAD on SCA with an overall accuracy of 64%, sensitivity of 40% and specificity of 83%. Dynamic SPECT image

  5. Parallel-hole collimator concept for stationary SPECT imaging.

    PubMed

    Pato, Lara R V; Vandenberghe, Stefaan; Zedda, Tiziana; Van Holen, Roel

    2015-11-21

    Parallel-hole SPECT collimators have traditionally been manufactured by stacking sheets of lead foil or by casting. These techniques significantly restrict our options in terms of collimator geometry. However, recent developments in metal additive manufacturing are making novel collimator designs possible, giving rise to new opportunities in SPECT imaging. In this paper we propose an innovative type of collimator for stationary SPECT, using parallel-holes whose collimation direction depends on their axial position. Its main advantage compared to current stationary SPECT systems (which are based on pinholes) is that, using only axial bed translations, we can achieve complete angular sampling of an increased portion of the transaxial area of the collimator bore. This allows the system to be much more compact than current stationary SPECT systems that image objects of the same size. We describe three possible designs, for full-body, brain and small-animal imaging, respectively, and test their feasibility using simulations. The system modeling method is validated against realistic Monte Carlo simulations, and then used in the evaluation of the systems' performances and reconstructions. The simulations show that the system is able to reconstruct objects occupying the predicted field of view ([Formula: see text] of the transaxial area of the bore) without sampling artifacts. In particular, we perform reconstructions from noisy projection data obtained for an activity and scanning time similar to standard protocols for the three applications, and the resulting images indicate the possibility of using the proposed systems in practice.

  6. Parallel-hole collimator concept for stationary SPECT imaging

    NASA Astrophysics Data System (ADS)

    Pato, Lara R. V.; Vandenberghe, Stefaan; Zedda, Tiziana; Van Holen, Roel

    2015-11-01

    Parallel-hole SPECT collimators have traditionally been manufactured by stacking sheets of lead foil or by casting. These techniques significantly restrict our options in terms of collimator geometry. However, recent developments in metal additive manufacturing are making novel collimator designs possible, giving rise to new opportunities in SPECT imaging. In this paper we propose an innovative type of collimator for stationary SPECT, using parallel-holes whose collimation direction depends on their axial position. Its main advantage compared to current stationary SPECT systems (which are based on pinholes) is that, using only axial bed translations, we can achieve complete angular sampling of an increased portion of the transaxial area of the collimator bore. This allows the system to be much more compact than current stationary SPECT systems that image objects of the same size. We describe three possible designs, for full-body, brain and small-animal imaging, respectively, and test their feasibility using simulations. The system modeling method is validated against realistic Monte Carlo simulations, and then used in the evaluation of the systems’ performances and reconstructions. The simulations show that the system is able to reconstruct objects occupying the predicted field of view (75% of the transaxial area of the bore) without sampling artifacts. In particular, we perform reconstructions from noisy projection data obtained for an activity and scanning time similar to standard protocols for the three applications, and the resulting images indicate the possibility of using the proposed systems in practice.

  7. Radiopharmaceuticals for SPECT cancer detection

    NASA Astrophysics Data System (ADS)

    Chernov, V. I.; Medvedeva, A. A.; Zelchan, R. V.; Sinilkin, I. G.; Stasyuk, E. S.; Larionova, L. A.; Slonimskaya, E. M.; Choynzonov, E. L.

    2016-08-01

    The purpose of the study was to assess the efficacy of single photon emission computed tomography (SPECT) with 199Tl and 99mTc-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 199Tl uptake was seen in all patients with benign breast and laryngeal lesions, indicating a 100% specificity of 199Tl SPECT. In the breast cancer patients, the increased 199Tl uptake in the breast was visualized in 94.8% patients, 99mTc-MIBI—in 93.4% patients. The increased 199Tl uptake in axillary lymph nodes was detected in 60% patients, and 99mTc-MIBI—in 93.1% patients. In patients with laryngeal/hypopharyngeal cancer, the sensitivity of SPECT with 199Tl and 99mTc-MIBI was 95%. The 199Tl SPECT sensitivity in identification of regional lymph node metastases in the patients with laryngeal/hypopharyngeal cancer was 75% and the 99mTc-MIBI SPECT sensitivity was 17%. The data obtained showed that SPECT with 199Tl and 99mTc-MIBI can be used as one of the additional imaging methods in detection of tumors.

  8. Radiopharmaceuticals for SPECT Cancer Detection

    NASA Astrophysics Data System (ADS)

    Chernov, V. I.; Medvedeva, A. A.; Zelchan, R. V.; Sinilkin, I. G.; Stasyuk, E. S.; Larionova, L. A.; Slonimskaya, E. M.; Choynzonov, E. L.

    2016-06-01

    The purpose of the study was to assess the efficacy of single photon emission computed tomography (SPECT) with 199Tl and 99mTc-MIBI in the detection of breast, laryngeal and hypopharyngeal cancers. Materials and Methods: a total of 220 patients were included into the study. Of them, there were 120 patients with breast lesions (100 patients with breast cancer and 20 patients with benign breast tumors) and '00 patients with laryngeal/hypopharyngeal diseases (80 patients with laryngeal/hypopharyngeal cancer and 20 patients with benign laryngeal/hypopharyngeal lesions). Results: no abnormal 199Tl uptake was seen in all patients with benign breast and laryngeal lesions, indicating a 100% specificity of 199Tl SPECT. In breast cancer patients, increased 199Tl uptake in the breast was visualized in 94.8% patients, 99mTc-MIBI in 93.4% patients. Increased 199Tl uptake in axillary lymph nodes was detected in 60% patients and 99mTc-MIBI in 93.1% patients. In patients with laryngeal/hypopharyngeal cancer, sensitivity of SPECT with 199Tl and 99mTc-MIBI were 95%. The 199Tl SPECT sensitivity in identification of regional lymph node metastases in patients with laryngeal/hypopharyngeal cancer was 75% and the 99mTc-MIBI SPECT sensitivity was 17%. Conclusion: the data obtained show that SPECT with 199Tl and 99mTc-MIBI can be used as one of the additional imaging methods in detection of tumors.

  9. A multiresolution restoration method for cardiac SPECT

    NASA Astrophysics Data System (ADS)

    Franquiz, Juan Manuel

    method was also assessed in 201Tl clinical SPECT studies. Phantom results demonstrated that the multiresolution algorithm compensated the liver spillover artifact, yielded uniform polar maps and improved significantly the accuracy in calculating myocardial defect size. The procedure does not require operator intervention and can be easily implemented in the clinical setting by using Fourier transform techniques. Finally, the extension of the multiresolution method to other SPECT procedures is discussed and recommended.

  10. 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.

  11. CT, MR and SPECT imaging in temporal lobe epilepsy.

    PubMed

    Duncan, R; Patterson, J; Hadley, D M; Macpherson, P; Brodie, M J; Bone, I; McGeorge, A P; Wyper, D J

    1990-01-01

    Cranial computed tomography (CT) with modified temporal lobe technique, 0.15T magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) were carried out on 30 patients with intractable temporal lobe epilepsy. Lateralising abnormalities were detected in 21/30 patients overall. Specific lesions were detected by CT in one patient and by MRI in seven patients (in one case bilateral). In addition CT detected asymmetry of the sylvian fissures or temporal horns in 10 patients, and MRI in eight patients. SPECT detected lateralising abnormalities in 19 patients (in five cases bilateral). It is concluded that low field MRI is superior to modified CT in demonstrating subtle structural lesions of the temporal lobe. Functional scanning with SPECT supports the evidence of origin of an epileptic focus in a substantial proportion of cases and may improve the selection of patients for surgery.

  12. 3D quantitative analysis of brain SPECT images

    NASA Astrophysics Data System (ADS)

    Loncaric, Sven; Ceskovic, Ivan; Petrovic, Ratimir; Loncaric, Srecko

    2001-07-01

    The main purpose of this work is to develop a computer-based technique for quantitative analysis of 3-D brain images obtained by single photon emission computed tomography (SPECT). In particular, the volume and location of ischemic lesion and penumbra is important for early diagnosis and treatment of infracted regions of the brain. SPECT imaging is typically used as diagnostic tool to assess the size and location of the ischemic lesion. The segmentation method presented in this paper utilizes a 3-D deformable model in order to determine size and location of the regions of interest. The evolution of the model is computed using a level-set implementation of the algorithm. In addition to 3-D deformable model the method utilizes edge detection and region growing for realization of a pre-processing. Initial experimental results have shown that the method is useful for SPECT image analysis.

  13. A COMPUTER MODEL OF LUNG MORPHOLOGY TO ANALYZE SPECT IMAGES

    EPA Science Inventory

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

  14. A COMPUTER MODEL OF LUNG MORPHOLOGY TO ANALYZE SPECT IMAGES

    EPA Science Inventory

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

  15. Progress in BazookaSPECT.

    PubMed

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

    2009-01-01

    Recent progress on a high-resolution, photon-counting gamma-ray and x-ray imager called BazookaSPECT is presented. BazookaSPECT is an example of a new class of scintillation detectors based on integrating detectors such as CCD(charge-coupled device) or CMOS(complementary metal-oxide semiconductor) sensors. BazookaSPECT is unique in that it makes use of a scintillator in close proximity to a microchannel plate-based image intensifier for up-front optical amplification of scintillation light. We discuss progress made in bringing about compact BazookaSPECT modules and in real-time processing of event data using graphics processing units (GPUs). These advances are being implemented in the design of a high-resolution rodent brain imager called FastSPECT III. A key benefit of up-front optical gain is that any CCD/CMOS sensor can now be utilized for photon counting. We discuss the benefits and feasibility of using CMOS sensors as photon-counting detectors for digital radiography, with application in mammography and computed tomography (CT). We present as an appendix a formal method for comparing various photon-counting integrating detectors using objective statistical criteria.

  16. Progress in BazookaSPECT

    PubMed Central

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

    2010-01-01

    Recent progress on a high-resolution, photon-counting gamma-ray and x-ray imager called BazookaSPECT is presented. BazookaSPECT is an example of a new class of scintillation detectors based on integrating detectors such as CCD(charge-coupled device) or CMOS(complementary metal-oxide semiconductor) sensors. BazookaSPECT is unique in that it makes use of a scintillator in close proximity to a microchannel plate-based image intensifier for up-front optical amplification of scintillation light. We discuss progress made in bringing about compact BazookaSPECT modules and in real-time processing of event data using graphics processing units (GPUs). These advances are being implemented in the design of a high-resolution rodent brain imager called FastSPECT III. A key benefit of up-front optical gain is that any CCD/CMOS sensor can now be utilized for photon counting. We discuss the benefits and feasibility of using CMOS sensors as photon-counting detectors for digital radiography, with application in mammography and computed tomography (CT). We present as an appendix a formal method for comparing various photon-counting integrating detectors using objective statistical criteria. PMID:21297897

  17. Utility of the SPECT Tc-99m labeled RBC blood pool scan in the detection of hepatic hemangiomas

    SciTech Connect

    Guze, B.H.; Hawkins, R.A.

    1989-11-01

    The sensitivity of SPECT imaging of hepatic blood pool activity using Tc-99m labeled RBCs was contrasted with magnetic resonance and CT imaging in 22 cases. SPECT is a noninvasive technique with a high sensitivity for the diagnosis of hepatic hemangiomas. It is helpful for clarifying equivocal magnetic resonance imaging results.

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

    SciTech Connect

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

    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 quantitatively consider the disadvantages associated with them. Methods: Our PET and SPECT simulation modules were developed using Monte Carlo simulation of Electrons and Photons (MCEP), developed by Dr. S. Uehara. PET code (MCEP-PET) generates a sinogram, and reconstructs the tomography image using a time-of-flight ordered subset expectation maximization (TOF-OSEM) algorithm with attenuation compensation. To evaluate MCEP-PET, simulated results of {sup 18}F PET imaging were compared with the experimental results. The results confirmed that MCEP-PET can simulate the experimental results very well. The SPECT code (MCEP-SPECT) models the collimator and NaI detector system, and generates the projection images and projection data. To save the computational time, the authors adopt the prerecorded {sup 90}Y bremsstrahlung photon data calculated by MCEP. The projection data are also reconstructed using the OSEM algorithm. The authors simulated PET and SPECT images of a water phantom containing six hot spheres filled with different concentrations of {sup 90}Y without background activity. The amount of activity was 163 MBq, with an acquisition time of 40 min. Results: The simulated {sup 90}Y-PET image accurately simulated the experimental results. PET image is visually

  19. Ventilation/Perfusion SPECT lung scintigraphy and computed tomography pulmonary angiography in patients with clinical suspicion of pulmonary embolism.

    PubMed

    Ibáñez-Bravo, S; Banzo, I; Quirce, R; Martínez-Rodríguez, I; Jiménez-Bonilla, J; Martínez-Amador, N; Parra, J A; González-Macías, J; Carril, J M

    2016-01-01

    The aim was to compare ventilation/perfusion SPECT lung scintigraphy (V/Q-SPECT) and computed tomography pulmonary angiography (CTPA) in patients with suspicion of pulmonary embolism (PE). This prospectively designed study included 53 patients with intermediate or high clinical probability of PE. A V/Q-SPECT and CTPA was performed on all patients. The V/Q-SPECT was interpreted according to the European Association of Nuclear Medicine and Molecular Imaging (EANMMI) guidelines. CTPA was reported as positive, negative, or indeterminate. CTPA was positive in 22 cases, negative in 28, and indeterminate in 3. V/Q-SPECT was positive in 27 cases, negative in 24, and non-diagnostic in 2. In the 22 with positive CTPA, V/Q-SPECT was positive in 18, negative in 3, and non-diagnostic in 1. In the 28 with negative CTPA, V/Q-SPECT was positive in 8, negative in 19, and non-diagnostic in 1. In the 3 with indeterminate CTPA, V/Q-SPECT was positive in 1 and negative in 2. In the 2 non-diagnostic cases V/Q-SPECT, CTPA was positive in 1 and negative in one. In the 10 high clinical probabilities, CTPA and V/Q-SPECT were positive in 7, negative in 2, and in 1, CTPA was positive and V/Q-SPECT negative. In the 38 intermediate probability group, CTPA and V/Q-SPECT were positive in 11, negative in 17, with CTPA negative and V/Q-SPECT positive in 8, and in 2 CTPA was positive and V/Q-SPECT negative. The results show that V/Q-SPECT detected PE in 5 patients more than CTPA. Our results show a 77% concordance of both techniques. Overall V/Q-SPECT detected PE in 18% more patients than CTPA in the intermediate group. Both techniques have a complementary role when a diagnosis cannot be made with one of them. Copyright © 2016 Elsevier España, S.L.U. and SEMNIM. All rights reserved.

  20. SPECT imaging with resolution recovery

    SciTech Connect

    Bronnikov, A. V.

    2011-07-01

    Single-photon emission computed tomography (SPECT) is a method of choice for imaging spatial distributions of radioisotopes. Many applications of this method are found in nuclear industry, medicine, and biomedical research. We study mathematical modeling of a micro-SPECT system by using a point-spread function (PSF) and implement an OSEM-based iterative algorithm for image reconstruction with resolution recovery. Unlike other known implementations of the OSEM algorithm, we apply en efficient computation scheme based on a useful approximation of the PSF, which ensures relatively fast computations. The proposed approach can be applied with the data acquired with any type of collimators, including parallel-beam fan-beam, cone-beam and pinhole collimators. Experimental results obtained with a micro SPECT system demonstrate high efficiency of resolution recovery. (authors)

  1. Radiopharmaceuticals for SPECT cancer detection

    SciTech Connect

    Chernov, V. I. Medvedeva, A. A. Zelchan, R. V. Sinilkin, I. G.; Stasyuk, E. S.; Larionova, L. A.; Slonimskaya, E. M.; Choynzonov, E. L.

    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}Tl 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.

  2. 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.

  3. [Utility of SPECT in gallium scintigraphy].

    PubMed

    Uto, Tomoyuki

    2002-11-01

    Whole-body gallium planar scintigraphy is a mainstay for the detection of tumors and inflammatory lesions. Recently, gallium SPECT (single photon emission computed tomography) has become more common in the clinical setting. This diagnostic modality is widely employed in our hospital, and lesions are actually detected by SPECT in some cases. Although the contrast of SPECT images is better than that of planar images, spatial resolution is limited by the limited matrix size. Thus, the overall diagnostic utility of SPECT remains to be confirmed. The usefulness of SPECT for the detection of gallium-accumulated lesions was evaluated in a phantom. In this study, we showed that SPECT is able to detect more smaller and lower gallium accumulations than planar imaging. Thus, SPECT imaging is useful in gallium scintigraphy.

  4. [Value of thallium 201-SPECT in typing brain space-occupying lesions].

    PubMed

    Martínez del Valle Torres, M D; Gómez Rio, M; Rodríguez Fernández, A; Sabatel Hernandez, G; Ortega Lozano, S; Ramos Font, C; Bellon Guardia, M; López Ramírez, E; Llamas Elvira, J M

    2004-01-01

    This study was designed to assess the diagnostic accuracy of single photon emission computed tomography with Tl-201 (SPECT Tl-201) to establish the tumoral or non-tumoral nature of brain space occupying lesions in comparison with usual diagnostic techniques. The study population consisted of 37 patients, 24 men (64.9 %) and 13 women (35.1 %), mean age 48 +/- 16 years. After establishing the clinical and radiological diagnosis of brain lesion, all patients underwent SPECT Tl-201, evaluating it only by subjective analysis and blinded to neuroestructural techniques. After surgical resection all patients were evaluated anatomopathologically to establish the histologic nature. The sensitivity of SPECT Tl-201 (0.87) was higher than standard neuroimaging techniques (0.78). Specificity (0.43), positive (0.87) and negative (0.43) predictive values of SPECT were similar to neuroestructural procedures (MRI and CT scan) with 0.43, 0.82 and 0.38 values. Tumoral disease prevalence was 0.81. Neuroestructural procedures were non-conclusive in 18.9 % of the studies. No non-conclusive results were obtained with SPECT Tl-201. SPECT Tl-201 is a diagnostic procedure of high sensitivity to establish the tumoral nature of brain lesions, with poor specificity, similar to structural X-ray techniques.

  5. SPECT myocardial perfusion imaging for the assessment of left ventricular mechanical dyssynchrony

    PubMed Central

    Chen, Ji; Garcia, Ernest V.; Bax, Jeroen J.; Iskandrian, Ami E.; Borges-Neto, Salvador; Soman, Prem

    2012-01-01

    Phase analysis of gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is an evolving technique for measuring LV mechanical dyssynchrony. Since its inception in 2005, it has undergone considerable technical development and clinical evaluation. This article reviews the background, the technical and clinical characteristics, and evolving clinical applications of phase analysis of gated SPECT MPI in patients requiring cardiac resynchronization therapy or implantable cardioverter defibrillator therapy and in assessing LV diastolic dyssynchrony. PMID:21567281

  6. Advances in SPECT and PET Hardware.

    PubMed

    Slomka, Piotr J; Pan, Tinsu; Berman, Daniel S; Germano, Guido

    2015-01-01

    There have been significant recent advances in single photon emission computed tomography (SPECT) and positron emission tomography (PET) hardware. Novel collimator designs, such as multi-pinhole and locally focusing collimators arranged in geometries that are optimized for cardiac imaging have been implemented to reduce imaging time and radiation dose. These new collimators have been coupled with solid state photon detectors to further improve image quality and reduce scanner size. The new SPECT scanners demonstrate up to a 7-fold increase in photon sensitivity and up to 2 times improvement in image resolution. Although PET scanners are used primarily for oncological imaging, cardiac imaging can benefit from the improved PET sensitivity of 3D systems without inter-plane septa and implementation of the time-of-flight reconstruction. Additionally, resolution recovery techniques are now implemented by all major PET vendors. These new methods improve image contrast, image resolution, and reduce image noise. Simultaneous PET/magnetic resonance (MR) hybrid systems have been developed. Solid state detectors with avalanche photodiodes or digital silicon photomultipliers have also been utilized in PET. These new detectors allow improved image resolution, higher count rate, as well as a reduced sensitivity to electromagnetic MR fields. Copyright © 2015. Published by Elsevier Inc.

  7. Practical reconstruction protocol for quantitative (90)Y bremsstrahlung SPECT/CT.

    PubMed

    Siman, W; Mikell, J K; Kappadath, S C

    2016-09-01

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

  8. Contribution of V/Q SPECT to planar scintigraphy in the diagnosis of pulmonary embolism.

    PubMed

    Quirce, R; Ibáñez-Bravo, S; Jiménez-Bonilla, J; Martínez-Rodríguez, I; Martínez-Amador, N; Ortega-Nava, F; Lavado-Pérez, C; Bravo-Ferrer, Z; Carril, J M

    2014-01-01

    To evaluate the feasibility of V/Q SPECT and analyze its contribution to planar V/Q lung scintigraphy in the diagnosis of pulmonary embolism (PE). A total of 109 patients with suspected PE showing Wells score>2 and elevated D-dimer were studied. The V/Q could not be completed in 7 patients, so they were excluded. Ventilation and perfusion scans were done using Technegas and (99m)Tc-MAA. Planar study included 8 projections on a 256×256 matrix and 128 projections on a 128×128 matrix were acquired for the SPECT study, applying an iterative method. Planar images were interpreted according to modified PIOPED criteria, and SPECT by the guidelines of the EANMMI. The results with both techniques were compared. V/Q planar scintigraphy and SPECT could be performed in 102 patients. V/Q planar scintigraphy was considered "diagnostic" in 39 of the 102 patients, and "non-diagnostic" in 63. Of the 39 "diagnostic" studies, 31 were reported as high probability of PE and 8 as normal. Of the 63 "non-diagnostic", 26 corresponded to intermediate, 29 to low, and 8 to very low probability. The SPECT study was "diagnostic" in 97 and indeterminate in only 5. All patients with a high probability planar scintigraphy had a positive SPECT. In the 8 patients with a normal planar scintigraphy SPECT was negative in 5 and positive in 3. In the 63 patients with a "non-diagnostic" planar scintigraphy SPECT was "diagnostic" in 58 of them, positive in 17 and negative in 41. V/Q SPECT is a feasible technique as it was performed in 102 of the 109 patients who were enrolled in the study (94%). The addition of V/Q SPECT to planar V/Q decreases the number of "non-diagnostic" reports from 62% in planar scintigraphy to 4.9% in SPECT. Therefore, V/Q SPECT should be included in the diagnosis approach of PE due to its high diagnostic yield. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

  9. 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.

  10. Molecular Imaging of Conscious, Unrestrained Mice with AwakeSPECT

    SciTech Connect

    Baba, Justin S.; Endres, Christopher J.; Foss, Catherine A.; Nimmagadda, Sridhar; Jung, Hyeyun; Goddard, James S.; Lee, Seung Joon; McKisson, John; Smith, Mark F.; Stolin, Alexander V.; Weisenberger, Andrew G.; Pomper, Martin G.

    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 from 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.

  11. Molecular Imaging of Conscious, Unrestrained Mice with AwakeSPECT

    SciTech Connect

    Baba, Justin S; Endres, Christopher; Foss, Catherine; Nimmagadda, Sridhar; Jung, Hyeyun; Goddard Jr, James Samuel; Lee, Seung Joon; McKisson, John; Smith, Mark F.; Stolin, Alexander; Weisenberger, Andrew G.; Pomper, Martin

    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 from 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.

  12. 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

  13. Filtering in SPECT Image Reconstruction

    PubMed Central

    Lyra, Maria; Ploussi, Agapi

    2011-01-01

    Single photon emission computed tomography (SPECT) imaging is widely implemented in nuclear medicine as its clinical role in the diagnosis and management of several diseases is, many times, very helpful (e.g., myocardium perfusion imaging). The quality of SPECT images are degraded by several factors such as noise because of the limited number of counts, attenuation, or scatter of photons. Image filtering is necessary to compensate these effects and, therefore, to improve image quality. The goal of filtering in tomographic images is to suppress statistical noise and simultaneously to preserve spatial resolution and contrast. The aim of this work is to describe the most widely used filters in SPECT applications and how these affect the image quality. The choice of the filter type, the cut-off frequency and the order is a major problem in clinical routine. In many clinical cases, information for specific parameters is not provided, and findings cannot be extrapolated to other similar SPECT imaging applications. A literature review for the determination of the mostly used filters in cardiac, brain, bone, liver, kidneys, and thyroid applications is also presented. As resulting from the overview, no filter is perfect, and the selection of the proper filters, most of the times, is done empirically. The standardization of image-processing results may limit the filter types for each SPECT examination to certain few filters and some of their parameters. Standardization, also, helps in reducing image processing time, as the filters and their parameters must be standardised before being put to clinical use. Commercial reconstruction software selections lead to comparable results interdepartmentally. The manufacturers normally supply default filters/parameters, but these may not be relevant in various clinical situations. After proper standardisation, it is possible to use many suitable filters or one optimal filter. PMID:21760768

  14. SPECT (Single-Photon Emission Computerized Tomography) Scan

    MedlinePlus

    SPECT scan Overview By Mayo Clinic Staff A single-photon emission computerized tomography (SPECT) scan lets your doctor analyze the function of some of your internal organs. A SPECT scan is a type of nuclear imaging test, ...

  15. NMF-Based Analysis of SPECT Brain Images for the Diagnosis of Alzheimer's Disease

    NASA Astrophysics Data System (ADS)

    Padilla, Pablo; Górriz, Juan-Manuel; Ramírez, Javier; Lang, Elmar; Chaves, Rosa; Segovia, Fermin; Álvarez, Ignacio; Salas-González, Diego; López, Miriam

    This paper offers a computer-aided diagnosis (CAD) technique for early diagnosis of Alzheimer's disease (AD) by means of single photon emission computed tomography (SPECT) image classification. The SPECT database for different patients is analyzed by applying the Fisher discriminant ratio (FDR) and non-negative matrix factorization (NMF) for the selection and extraction of the most significative features of each patient SPECT data, in order to reduce the large dimensionality of the input data and the problem of the curse of dimensionality, extracting score features. The NMF-transformed set of data, with reduced number of features, is classified by means of support vector machines (SVM) classification. The proposed NMF+SVM method yields up to 94% classification accuracy, thus becoming an accurate method for SPECT image classification. For the sake of completeness, comparison between conventional PCA+SVM method and the proposed method is also provided.

  16. Combined SPECT/CT and PET/CT for breast imaging

    NASA Astrophysics Data System (ADS)

    Russo, Paolo; Larobina, Michele; Di Lillo, Francesca; Del Vecchio, Silvana; Mettivier, Giovanni

    2016-02-01

    In the field of nuclear medicine imaging, breast imaging for cancer diagnosis is still mainly based on 2D imaging techniques. Three-dimensional tomographic imaging with whole-body PET or SPECT scanners, when used for imaging the breast, has performance limits in terms of spatial resolution and sensitivity, which can be overcome only with a dedicated instrumentation. However, only few hybrid imaging systems for PET/CT or SPECT/CT dedicated to the breast have been developed in the last decade, providing complementary functional and anatomical information on normal breast tissue and lesions. These systems are still under development and clinical trials on just few patients have been reported; no commercial dedicated breast PET/CT or SPECT/CT is available. This paper reviews combined dedicated breast PET/CT and SPECT/CT scanners described in the recent literature, with focus on their technological aspects.

  17. MIRD pamphlet No. 23: quantitative SPECT for patient-specific 3-dimensional dosimetry in internal radionuclide therapy.

    PubMed

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

    2012-08-01

    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.

  18. In Vivo Dosimetry Of Patients Submitted To Brain Spect Studies

    NASA Astrophysics Data System (ADS)

    Cruz-Cortés, D.; Azorín, J.; Saucedo, V. M.

    2004-09-01

    Single photon emission computed tomography (SPECT) is a diagnosis technique which allows to visualize a three dimensional distribution of a radioactive material in the brain. This technique is used for evaluating the blood flux and the metabolic function of the diverse brain regions and is very useful to diagnostic several pathologies such as Alzheimer disease, tumors, epilepsy brain hemorrhages, etc. The radioactive tracer used is 99mTc-labeled hexamethylpropyleneamineoxime (99mTc-HMPAO). We present the results obtained from measurements performed in the chest, back and skull of patients submitted to brain SPECT studies during two hours using home-made LiF:Mg,Cu,P+PTFE thermoluminescent dosimeters. Results obtained showed that the dose received by the patients during two hours are lower than 0.3 mGy.

  19. [SPECT radiopharmaceuticals -- novelties and new possibilities].

    PubMed

    Balogh, Lajos; Polyák, András; Pöstényi, Zita; Haász, Veronika; Dabasi, Gabriella; Jóba, Róbert; Bús, Katalin; Jánoki, Gergely; Thuróczy, Julianna; Zámbó, Katalin; Garai, Ildikó; Környei, József; Jánoki, Gyõzõ

    2014-12-01

    Actual state of affairs and future perspectives of SPECT radiopharmaceuticals regarding local and international data were summarized. Beyond conventional gamma-emitting radioisotopes, localization studies with beta emitting therapeutic radiopharmaceuticals hold increasing importance. Extension of hybrid (SPECT/CT) equipments has modified conventional scintigraphic and SPECT methods as well but more important changes come into the world through novel ligands for specific diagnoses and therapy.

  20. Iterative restoration of SPECT projection images

    NASA Astrophysics Data System (ADS)

    Glick, S. J.; Xia, Weishi

    1997-04-01

    Photon attenuation and the limited nonstationary spatial resolution of the detector can reduce both qualitative and quantitative image quality in single photon emission computed tomography (SPECT). In this paper, a reconstruction approach is described which can compensate for both of these degradations. The approach involves processing the projection data with Bellini's method for attenuation compensation followed by an iterative deconvolution technique which uses the frequency distance principle (FDP) to model the distance-dependent camera blur. Modeling of the camera blur with the FDP allows an efficient implementation using fast Fourier transform (FFT) methods. After processing of the projection data, reconstruction is performed using filtered backprojection. Simulation studies using two different brain phantoms show that this approach gives reconstructions with a favorable bias versus noise tradeoff, provides no visually undesirable noise artifacts, and requires a low computational load.

  1. Cervical SPECT Camera for Parathyroid Imaging

    SciTech Connect

    None, None

    2012-08-31

    Primary hyperparathyroidism characterized by one or more enlarged parathyroid glands has become one of the most common endocrine diseases in the world affecting about 1 per 1000 in the United States. Standard treatment is highly invasive exploratory neck surgery called Parathyroidectomy. The surgery has a notable mortality rate because of the close proximity to vital structures. The move to minimally invasive parathyroidectomy is hampered by the lack of high resolution pre-surgical imaging techniques that can accurately localize the parathyroid with respect to surrounding structures. We propose to develop a dedicated ultra-high resolution (~ 1 mm) and high sensitivity (10x conventional camera) cervical scintigraphic imaging device. It will be based on a multiple pinhole-camera SPECT system comprising a novel solid state CZT detector that offers the required performance. The overall system will be configured to fit around the neck and comfortably image a patient.

  2. Physiological imaging with PET and SPECT in Dementia

    SciTech Connect

    Jagust, W.J. . Dept. of Neurology Lawrence Berkeley Lab., CA )

    1989-10-01

    Dementia is a medical problem of increasingly obvious importance. The most common cause of dementia, Alzheimer's disease (AD) accounts for at least 50% of all cases of dementia, with multi-infarct dementia the next most common cause of the syndrome. While the accuracy of diagnosis of AD may range from 80 to 90%, there is currently no laboratory test to confirm the diagnosis. Functional imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) offer diagnostic advantages since brain function is unequivocally disturbed in all dementing illnesses. Both PET and SPECT have been utilized in the study of dementia. While both techniques rely on principles of emission tomography to produce three dimensional maps of injected radiotracers, the differences between positron and single photon emission have important consequences for the practical applications of the two procedures. This briefly reviews the technical differences between PET and SPECT, and discusses how both techniques have been used in our laboratory to elucidate the pathophysiology of dementia. 32 refs., 2 figs.

  3. Organ volume estimation using SPECT

    SciTech Connect

    Zaidi, H.

    1996-06-01

    Knowledge of in vivo thyroid volume has both diagnostic and therapeutic importance and could lead to a more precise quantification of absolute activity contained in the thyroid gland. In order to improve single-photon emission computed tomography (SPECT) quantitation, attenuation correction was performed according to Chang`s algorithm. The dual window method was used for scatter subtraction. The author used a Monte Carlo simulation of the SPECT system to accurately determine the scatter multiplier factor k. Volume estimation using SPECT was performed by summing up the volume elements (voxels) lying within the contour of the object, determined by a fixed threshold and the gray level histogram (GLH) method. Thyroid phantom and patient studies were performed and the influence of (1) fixed thresholding, (2) automatic thresholding, (3) attenuation, (4) scatter, and (5) reconstruction filter were investigated. This study shows that accurate volume estimation of the thyroid gland is feasible when accurate corrections are performed. The relative error is within 7% for the GLH method combined with attenuation and scatter corrections.

  4. Filters in 2D and 3D Cardiac SPECT Image Processing.

    PubMed

    Lyra, Maria; Ploussi, Agapi; Rouchota, Maritina; Synefia, Stella

    2014-01-01

    Nuclear cardiac imaging is a noninvasive, sensitive method providing information on cardiac structure and physiology. Single photon emission tomography (SPECT) evaluates myocardial perfusion, viability, and function and is widely used in clinical routine. The quality of the tomographic image is a key for accurate diagnosis. Image filtering, a mathematical processing, compensates for loss of detail in an image while reducing image noise, and it can improve the image resolution and limit the degradation of the image. SPECT images are then reconstructed, either by filter back projection (FBP) analytical technique or iteratively, by algebraic methods. The aim of this study is to review filters in cardiac 2D, 3D, and 4D SPECT applications and how these affect the image quality mirroring the diagnostic accuracy of SPECT images. Several filters, including the Hanning, Butterworth, and Parzen filters, were evaluated in combination with the two reconstruction methods as well as with a specified MatLab program. Results showed that for both 3D and 4D cardiac SPECT the Butterworth filter, for different critical frequencies and orders, produced the best results. Between the two reconstruction methods, the iterative one might be more appropriate for cardiac SPECT, since it improves lesion detectability due to the significant improvement of image contrast.

  5. Filters in 2D and 3D Cardiac SPECT Image Processing

    PubMed Central

    Ploussi, Agapi; Synefia, Stella

    2014-01-01

    Nuclear cardiac imaging is a noninvasive, sensitive method providing information on cardiac structure and physiology. Single photon emission tomography (SPECT) evaluates myocardial perfusion, viability, and function and is widely used in clinical routine. The quality of the tomographic image is a key for accurate diagnosis. Image filtering, a mathematical processing, compensates for loss of detail in an image while reducing image noise, and it can improve the image resolution and limit the degradation of the image. SPECT images are then reconstructed, either by filter back projection (FBP) analytical technique or iteratively, by algebraic methods. The aim of this study is to review filters in cardiac 2D, 3D, and 4D SPECT applications and how these affect the image quality mirroring the diagnostic accuracy of SPECT images. Several filters, including the Hanning, Butterworth, and Parzen filters, were evaluated in combination with the two reconstruction methods as well as with a specified MatLab program. Results showed that for both 3D and 4D cardiac SPECT the Butterworth filter, for different critical frequencies and orders, produced the best results. Between the two reconstruction methods, the iterative one might be more appropriate for cardiac SPECT, since it improves lesion detectability due to the significant improvement of image contrast. PMID:24804144

  6. 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.

  7. 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.

  8. The optimized evaluation of diabetic foot infection by dual isotope SPECT/CT imaging protocol.

    PubMed

    Heiba, Sherif I; Kolker, Dov; Mocherla, Bharat; Kapoor, Karan; Jiang, Manli; Son, Hongju; Rangaswamy, Balasubramanya; Kostakoglu, Lale; Savitch, Ina; DaCosta, Maria; Machac, Josef

    2010-01-01

    Sequential Tc-99m hydroxymethylene-diphosphonate (HDP) 3-phase bone (BS) and In-111 leukocyte scanning (WBCS) have been frequently used to evaluate the diabetic foot, as nonosteomyelitis BS uptake is repeatedly observed and osteomyelitis (OM) in WBCS is often uncertain without BS correlation. Additionally, both modalities are limited in lesion localization because of low resolution and lack of anatomic details. We investigated a method that combined BS/WBCS, and if needed, WBCS/bone marrow scanning (BMS) using SPECT/CT to accurately diagnose/localize infection in a practical protocol. Blood flow/pool images were obtained followed by WBC reinjection and next day dual isotope (DI) BS/WBCS planar and SPECT/CT. BMS/WBCS SPECT/CT (step 2 DI) was obtained on the following day when images were suspicious for mid/hindfoot OM. Diagnosis accuracy and confidence were judged for the various imaging combinations. Diagnosis was classified as OM, soft tissue infection (STI), both OM/STI, and other/no bony pathology by microbiology/pathology or follow-up. Distinction between various diagnostic categories and overall OM diagnostic accuracy in 213 patients were higher for DI than WBCS or BS alone, and for DI SPECT/CT than DI planar or SPECT only. Diagnostic confidence/lesion site was significantly higher for DI SPECT/CT than other comparative imaging methods. In a group of 97 patients with confirmed microbiologic/pathologic diagnosis, similar results were attained. Step 2 DI SPECT/CT performed in 67 patients further improved diagnostic accuracy/confidence. DI SPECT/CT is a highly accurate modality that considerably improves detection and discrimination of STI and OM while providing precise anatomic localization in the diabetic foot. This combined imaging technique promises to beneficially impact diabetic patient care. Copyright © 2010 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Combining SPECT and Quantitative EEG Analysis for the Automated Differential Diagnosis of Disorders with Amnestic Symptoms

    PubMed Central

    Höller, Yvonne; Bathke, Arne C.; Uhl, Andreas; Strobl, Nicolas; Lang, Adelheid; Bergmann, Jürgen; Nardone, Raffaele; Rossini, Fabio; Zauner, Harald; Kirschner, Margarita; Jahanbekam, Amirhossein; Trinka, Eugen; Staffen, Wolfgang

    2017-01-01

    Single photon emission computed tomography (SPECT) and Electroencephalography (EEG) have become established tools in routine diagnostics of dementia. We aimed to increase the diagnostic power by combining quantitative markers from SPECT and EEG for differential diagnosis of disorders with amnestic symptoms. We hypothesize that the combination of SPECT with measures of interaction (connectivity) in the EEG yields higher diagnostic accuracy than the single modalities. We examined 39 patients with Alzheimer's dementia (AD), 69 patients with depressive cognitive impairment (DCI), 71 patients with amnestic mild cognitive impairment (aMCI), and 41 patients with amnestic subjective cognitive complaints (aSCC). We calculated 14 measures of interaction from a standard clinical EEG-recording and derived graph-theoretic network measures. From regional brain perfusion measured by 99mTc-hexamethyl-propylene-aminoxime (HMPAO)-SPECT in 46 regions, we calculated relative cerebral perfusion in these patients. Patient groups were classified pairwise with a linear support vector machine. Classification was conducted separately for each biomarker, and then again for each EEG- biomarker combined with SPECT. Combination of SPECT with EEG-biomarkers outperformed single use of SPECT or EEG when classifying aSCC vs. AD (90%), aMCI vs. AD (70%), and AD vs. DCI (100%), while a selection of EEG measures performed best when classifying aSCC vs. aMCI (82%) and aMCI vs. DCI (90%). Only the contrast between aSCC and DCI did not result in above-chance classification accuracy (60%). In general, accuracies were higher when measures of interaction (i.e., connectivity measures) were applied directly than when graph-theoretical measures were derived. We suggest that quantitative analysis of EEG and machine-learning techniques can support differentiating AD, aMCI, aSCC, and DCC, especially when being combined with imaging methods such as SPECT. Quantitative analysis of EEG connectivity could become an

  10. Lymphoma: evaluation with Ga-67 SPECT

    SciTech Connect

    Tumeh, S.S.; Rosenthal, D.S.; Kaplan, W.D.; English, R.J.; Holman, B.L.

    1987-07-01

    To determine the value of gallium-67 single photon emission computed tomography (SPECT) in imaging patients with lymphoma, the authors compared Ga-67 planar images and SPECT images in 40 consecutive patients, using radiologic examinations and/or medical records to confirm the presence or absence of disease. Thirty-three patients had Hodgkin disease, and seven had non-Hodgkin lymphoma. Fifty-four examinations were performed. Of 57 sites of lymphoma in the chest, planar imaging depicted 38, while SPECT depicted 55, resulting in sensitivities of 0.66 and 0.96 for planar and SPECT imaging, respectively. In eight sites, both modalities were truly negative, but SPECT was negative in four additional sites that were equivocal on planar imaging, resulting in specificities of 0.66 and 1.00 for planar and SPECT imaging, respectively. In the abdomen, the sensitivities of planar and SPECT imaging were 0.69 and 0.85, and the specificities 0.87 and 1.00, respectively. SPECT was more accurate in depicting foci of gallium-avid lymphoma in the chest and abdomen and in excluding disease when planar imaging was equivocal.

  11. 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.

  12. Single photon emission photography/magnetic resonance imaging (SPECT/MRI) visualization for frontal-lobe-damaged regions

    NASA Astrophysics Data System (ADS)

    Stokking, Rik; Zuiderveld, Karel J.; Hulshoff Pol, Hilleke E.; Viergever, Max A.

    1994-09-01

    We present multi-modality visualization strategies to convey information contained in registered Single Photon Emission Photography (SPECT) and Magnetic Resonance (MR) images of the brain. Multi-modality visualization provides a means to retrieve valuable information from the data which might otherwise remain obscured. Here we use MRI as an anatomical framework for functional information acquired with SPECT. This is part of clinical research studying the change of functionality caused by a frontal lobe damaged region. A number of known and newly developed techniques for the integrated visualization of SPECT and MR images will be discussed.

  13. 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

  14. Implications of CT noise and artifacts for quantitative {sup 99m}Tc SPECT/CT imaging

    SciTech Connect

    Hulme, K. W.; Kappadath, S. C.

    2014-04-15

    CT dose levels that affect SPECT quantification is low (CTDI{sub vol} ∼ 4 μGy), the low dose limit for the CT exam as part of SPECT/CT will be guided by CT image quality requirements for anatomical localization and artifact reduction. A CT technique with higher kVp in combination with lower mAs is recommended when low-dose CT images are used for AC to minimize beam-hardening artifacts.

  15. Role of SPECT-CT in breast cancer sentinel node biopsy when internal mammary chain drainage is observed.

    PubMed

    Serrano-Vicente, J; Rayo-Madrid, J I; Domínguez-Grande, M L; Infante-Torre, J R; García-Bernardo, L; Moreno-Caballero, M; Medina-Romero, F; Durán-Barquero, C

    2016-04-01

    SPECT-CT in the detection of the sentinel lymph node (SLN) of breast cancer offers known advantages over conventional planar lymphoscintigraphy. Sometimes, it shows atypical findings like mediastinal lymphatic drainage. We have evaluated these atypical findings showed by SPECT-CT performed in patients with migration to the internal mammary chain (IMC) and their roles in the management of the patients. We reviewed the 56 lymphoscintigraphies (planar and SPECT-CT) of 56 women (average age: 55 years) diagnosed with breast cancer with IMC migration observed in the planar images. We compared the two techniques, obtaining the number of depicted nodes, atypical locations, their exact anatomical location and their role in the management of the patient. Planar images showed a total number of 81 IMC nodes. SPECT-CT showed 74 nodes in the IMC territory and 14 mediastinal lymphatic nodes in 6 patients. Out of the 81 IMC nodes reported by planar images, seven corresponded to mediastinal nodes. Planar and hybrid images showed 110 and 130 axillary nodes, respectively. SPECT-CT showed additional findings in five patients: three infraclavicular and two supraclavicular nodes that were exactly located. One intramammary node was discarded by the SPECT-CT as a focal skin contamination. Mediastinal nodes are unexpected, but not uncommon findings that are important in the planning of SLN biopsy. SPECT-CT found more nodes than planar images, being able to separate mediastinal and IMC nodes, helping to exactly depict the SLN and its relations with anatomical structures.

  16. Evaluation of attenuation corrections using Monte Carlo simulated lung SPECT

    NASA Astrophysics Data System (ADS)

    Gustafsson, Agnetha; Bake, Björn; Jacobsson, Lars; Johansson, Åke; Ljungberg, Michael; Moonen, Michaela

    1998-08-01

    SPECT (single photon emission computed tomography) images are distorted by photon attenuation. The effect is complex in the thoracic region due to different tissue densities. This study compares the effect on the image homogeneity of two different methods of attenuation correction in lung SPECT; one pre-processing and one post-processing method. This study also investigates the impact of attenuation correction parameters such as lung contour, body contour, density of the lung tissue and effective attenuation coefficient. The Monte Carlo technique was used to simulate SPECT studies of a digital thorax phantom containing a homogeneous activity distribution in the lung. Homogeneity in reconstructed images was calculated as the coefficient of variation (CV). The isolated effect of the attenuation correction was assessed by normalizing pixel values from the attenuation corrected lung by pixel values from the lung with no attenuation effects. Results show that the CV decreased from 12.8% with no attenuation correction to 4.4% using the post-processing method and true densities in the thoracic region. The impact of variations in the definition of the body contour was found to be marginal while the corresponding effect of variations in the lung contour was substantial.

  17. 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

  18. Blind deconvolution of human brain SPECT images using a distribution mixture estimation

    NASA Astrophysics Data System (ADS)

    Mignotte, Max; Meunier, Jean

    2000-06-01

    Thanks to its ability to yield functionally-based information, the SPECT imagery technique has become a great help in the diagnostic of cerebrovascular diseases. Nevertheless, due to the imaging process, SPECT images are blurred and consequently their interpretation by the clinician is often difficult. In order to improve the spatial resolution of these images and then to facilitate their interpretation, we propose herein to implement a deconvolution procedure relying on an accurate distribution mixture parameter estimation procedure. Parameters of this distribution mixture are efficiently exploited in order to prevent overfitting of the noisy data or to determine the support of the object to be deconvolved when this one is needed. In this context, we compare the deconvolution results obtained by the Lucy-Richardson method and by the recent blind deconvolution technique called the NAS-RIF algorithm on real and simulated brain SPECT images. The NAS-RIF performs the best and shows significant contrast enhancement with little mottle (noise) amplification.

  19. Integration of AdaptiSPECT, a small-animal adaptive SPECT imaging system

    PubMed Central

    Chaix, Cécile; Kovalsky, Stephen; Kosmider, Matthew; Barrett, Harrison H.; Furenlid, Lars R.

    2015-01-01

    AdaptiSPECT is a pre-clinical adaptive SPECT imaging system under final development at the Center for Gamma-ray Imaging. The system incorporates multiple adaptive features: an adaptive aperture, 16 detectors mounted on translational stages, and the ability to switch between a non-multiplexed and a multiplexed imaging configuration. In this paper, we review the design of AdaptiSPECT and its adaptive features. We then describe the on-going integration of the imaging system. PMID:26347197

  20. SPECT Imaging: Basics and New Trends

    NASA Astrophysics Data System (ADS)

    Hutton, Brian F.

    Single Photon Emission Computed Tomography (SPECT) is widely used as a means of imaging the distribution of administered radiotracers that have single-photon emission. The most widely used SPECT systems are based on the Anger gamma camera, usually involving dual detectors that rotate around the patient. Several factors affect the quality of SPECT images (e.g., resolution and noise) and the ability to perform absolute quantification (e.g., attenuation, scatter, motion, and resolution). There is a trend to introduce dual-modality systems and organ-specific systems, both developments that enhance diagnostic capability.

  1. 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.

  2. Role of SPECT and SPECT/CT in the Surgical Treatment of Primary Hyperparathyroidism

    PubMed Central

    Taubman, Michele L.; Goldfarb, Melanie; Lew, John I.

    2011-01-01

    Primary hyperparathyroidism is the most common cause of hypercalcemia in the outpatient population. This condition is usually the result of a single hyperfunctioning parathyroid gland. Targeted parathyroidectomy guided by intraoperative parathyroid hormone monitoring (IPM) through a small cervical incision has replaced traditional bilateral neck exploration (BNE) as the initial approach in the surgical treatment of primary hyperparathyroidism at many medical centers worldwide. Preoperative sestamibi-technetium 99m scintigraphy serves as an important prerequisite for successful targeted parathyroidectomy. Single-photon emission computed tomography (SPECT) and CT fusion, however, is a recent imaging technique that provides a three-dimensional functional image with advanced contrast resolution to greatly improve preoperative localization of parathyroid tumors. PMID:21776381

  3. Brain SPECT and transcranial Doppler (TCD) evaluation of the effects of intra-arterial papaverine for cerebral vasospasm

    SciTech Connect

    Lewis, D.H.; Newell, D.W.; Eskridge, J.M.

    1994-05-01

    Cerebral vasospasm (cv) is a common and serious consequence of subarachnoid hemorrhage. Interventional neuroradiologic techniques for treating cv refractory to medical and hemodynamic measures have included transluminal microballoon angioplasty and intra-arterial papaverine infusion (pap). Eight patients (pts) who had symptomatic cv but were not candidates for microballoon angioplasty received pap via arterial catheter. All 8 pts had brain SPECT with Tc-99m HMPAO and 7 had TCD readings before and after treatment. One pt had 2 separate treatments. Total treatments = 9. Results: Of the total of 9 treatments: 5 demonstrated marked improvement in regional cerebral blood flow on SPECT in the vascular territories that were ischemic, 3 showed mild to moderate improvement of blood flow, and 1 was unchanged. The pt that did not improve on SPECT died due to cardiorespiratory problems but remained comatose without neurologic improvement after the treatment. The other 8 had either prompt clinical improvement or modestly delayed improvement due to concomitant hydrocephalus. infection, recurrent vasospasm or other intervening medical problems. TCD readings in the treated vessels showed improved (lower) velocities that agreed with SPECT improvement after 4 intra-arterial pap treatments. There were 4 discrepancies of SPECT and TCD: 1 with rising TCD velocity in the mild cv range in the treated vessel that demonstrated SPECT improvement; 1 with unchanged velocity in the moderate cv range that showed SPECT improvement; 1 that showed lower velocity in the moderate cv range while the SPECT was unchanged; and 1 that had normal TCD velocities before and after treatment but high pulsatility indices on Doppler (which are characteristic of either elevated intra-cranial pressure or distal vessel disease) who had mild to moderate improvement of blood flow on SPECT after treatment.

  4. 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.

  5. Assessment of poststress left ventricular ejection fraction by gated SPECT: comparison with equilibrium radionuclide angiocardiography.

    PubMed

    Acampa, Wanda; Caprio, Maria Grazia; Nicolai, Emanuele; Liuzzi, Raffaele; De Luca, Serena; Capasso, Enza; Luongo, Luca; Petretta, Mario; Cuocolo, Alberto

    2010-02-01

    We compared left ventricular (LV) ejection fraction obtained by gated SPECT with that obtained by equilibrium radionuclide angiocardiography in a large cohort of patients. Within 1 week, 514 subjects with suspected or known coronary artery disease underwent same-day stress-rest (99m)Tc-sestamibi gated SPECT and radionuclide angiocardiography. For both studies, data were acquired 30 min after completion of exercise and after 3 h rest. In the overall study population, a good correlation between ejection fraction measured by gated SPECT and by radionuclide angiocardiography was observed at rest (r=0.82, p<0.0001) and after stress (r=0.83, p<0.0001). In Bland-Altman analysis, the mean differences in ejection fraction (radionuclide angiocardiography minus gated SPECT) were -0.6% at rest and 1.7% after stress. In subjects with normal perfusion (n=362), a good correlation between ejection fraction measured by gated SPECT and by radionuclide angiocardiography was observed at rest (r=0.72, p<0.0001) and after stress (r=0.70, p<0.0001) and the mean differences in ejection fraction were -0.9% at rest and 1.4% after stress. Also in patients with abnormal perfusion (n=152), a good correlation between the two techniques was observed both at rest (r=0.89, p<0.0001) and after stress (r=0.90, p<0.0001) and the mean differences in ejection fraction were 0.1% at rest and 2.5% after stress. In a large study population, a good agreement was observed in the evaluation of LV ejection fraction between gated SPECT and radionuclide angiocardiography. However, in patients with perfusion abnormalities, a slight underestimation in poststress LV ejection fraction was observed using gated SPECT as compared to equilibrium radionuclide angiocardiography.

  6. Awake animal SPECT: Overview and initial results

    SciTech Connect

    Weisenberger, A G; Majewski, S; McKisson, J; Popov, V; Proffitt, J; Stolin, A; Baba, J S; Goddard, J S; Lee, S J; Smith, M F; Tsui, B; Pomper, M

    2009-02-01

    A SPECT / X-ray CT system configured at Johns Hopkins University to image the biodistribution of radiopharmaceuticals in unrestrained, un-anesthetized mice has been constructed and tested on awake mice. The system was built by Thomas Jefferson National Accelerator Facility and Oak Ridge National Laboratory. SPECT imaging is accomplished using two gamma cameras, 10 cm × 20 cm in size based on a 2 × 4 array of Hamamatsu H8500 flat panel position sensitive photomultiplier tubes. A real-time optical tracking system utilizing three infrared cameras provides time stamped pose data of an awake mouse head during a SPECT scan. The six degrees of freedom (three translational and three rotational) pose data are used for motion correction during 3-D tomographic list-mode iterative image reconstruction. SPECT reconstruction of awake, unrestrained mice with motion compensation for head movement has been accomplished.

  7. SPECT assay of radiolabeled monoclonal antibodies

    SciTech Connect

    Jaszczak, R.J.

    1992-02-01

    The long-term goal of this research project is to develop methods to improve the utility of single photon emission computed tomography (SPECI) to quantify the biodistribution of monoclonal antibodies (MoAbs) labeled with clinically relevant radionuclides ({sup 123}I, {sup 131}I, and {sup 111}In) and with another radionuclide,{sup 211}At, recently used in therapy. We describe here our progress in developing quantitative SPECT methodology for {sup 111}In and {sup 123}I. We have focused our recent research thrusts on the following aspects of SPECT: (1) The development of improved SPECT hardware, such as improved acquisition geometries. (2) The development of better reconstruction methods that provide accurate compensation for the physical factors that affect SPECT quantification. (3) The application of carefully designed simulations and experiments to validate our hardware and software approaches.

  8. Hypoglycaemic hemiplegia: a repeat SPECT study.

    PubMed Central

    Shintani, S; Tsuruoka, S; Shiigai, T

    1993-01-01

    During a hypoglycaemic right hemiplegia induced by a deliberate overdose of oral hypoglycaemics, brain CT and angiography revealed no abnormalities. SPECTs made one day and six days later showed relative hypoperfusion in the left hemisphere. Repeat SPECT study suggested that the left hemisphere was more vulnerable than the right in the cerebral blood perfusion. This vulnerability might provoke the right hemiplegia in a critical condition, such as severe hypoglycaemia. Images PMID:8509788

  9. Cerebral SPECT imaging: Impact on clinical management

    SciTech Connect

    Bloom, M.; Jacobs, S.; Pozniakof, T.

    1994-05-01

    Although cerebral SPECT has been reported to be of value in a variety of neurologic disorders, there is limited data available on the value of SPECT relative to clinical management decisions. The purpose of this study was to determine the effect of cerebral SPECT imaging on patient management. A total of 94 consecutive patients referred for clinical evaluation with brain SPECT were included in this study. Patients were assigned to one of nine groups depending on the clinical indication for the study. These groups included transient ischemia (16), stroke (20), dementia (18), seizures (5), hemorrhage (13), head trauma (6), arteriovenous malformations (6), encephalopathy (6) and a miscellaneous (4) group. All patients were injected with 99mTc HMPAO in doses ranging from 15 mCi to 22 mCi (555 MBq to 814 MBq) and scanned on a triple headed SPECT gamma camera. Two weeks after completion of the study, a standardized interview was conducted between the nuclear and referring physicians to determine if the SPECT findings contributed to an alteration in patient management. Overall, patient management was significantly altered in 47% of the cases referred. The greatest impact on patient management occurred in the group evaluated for transient ischemia, where a total of 13/16 (81%) of patients had their clinical management altered as a result of the cerebral SPECT findings. Clinical management was altered in 61% of patients referred for evaluation of dementia, 67% of patients evaluated for arteriovenous malformations, and 50% of patients with head trauma. In the remainder of the patients, alteration in clinical management ranged from 17% to 50% of patients. This study demonstrates the clinical utility of cerebral SPECT imaging since in a significant number of cases clinical management was altered as a result of the examination. Long term follow up will be necessary to determine patient outcome.

  10. ADAPTIVE SMALL-ANIMAL SPECT/CT

    PubMed Central

    Furenlid, L.R.; Moore, J.W.; Freed, M.; Kupinski, M.A.; Clarkson, E.; Liu, Z.; Wilson, D.W.; Woolfenden, J.M.; Barrett, H.H.

    2015-01-01

    We are exploring the concept of adaptive multimodality imaging, a form of non-linear optimization where the imaging configuration is automatically adjusted in response to the object. Preliminary studies suggest that substantial improvement in objective, task-based measures of image quality can result. We describe here our work to add motorized adjustment capabilities and a matching CT to our existing FastSPECT II system to form an adaptive small-animal SPECT/CT. PMID:26617457

  11. Brain SPECT quantitation in clinical diagnosis

    SciTech Connect

    Hellman, R.S.

    1991-12-31

    Methods to quantitate SPECT data for clinical diagnosis should be chosen so that they take advantage of the lessons learned from PET data. This is particularly important because current SPECT high-resolution brain imaging systems now produce images that are similar in resolution to those generated by the last generation PET equipment (9 mm FWHM). These high-resolution SPECT systems make quantitation of SPECT more problematic than earlier. Methodology validated on low-resolution SPECT systems may no longer be valid for data obtained with the newer SPECT systems. For example, in patients with dementia, the ratio of parietal to cerebellar activity often was studied. However, with new instruments, the cerebellum appears very different: discrete regions are more apparent. The large cerebellar regions usually used with older instrumentation are of an inappropriate size for the new equipment. The normal range for any method of quantitation determined using older equipment probably changes for data obtained with new equipment. It is not surprising that Kim et al. in their simulations demonstrated that because of the finite resolution of imaging systems, the ability to measure pure function is limited, with {open_quotes}anatomy{close_quotes} and {open_quotes}function{close_quotes} coupled in a {open_quotes}complex nonlinear way{close_quotes}. 11 refs.

  12. Lymphoscintigraphic SPECT/CT-Contralateral Axillary Sentinel Lymph Node Drainage in Breast Cancer.

    PubMed

    Koyyalamudi, Ratna T; Rossleigh, Monica Anne

    2017-02-01

    A 58-year-old woman with previous right breast carcinoma treated with lumpectomy, right axillary clearance, chemo-radiotherapy, and adjuvant hormonal therapy underwent a lymphoscintigraphy for a new right breast lesion. On planar images, an alternate route of lymphatic drainage was observed to the right internal mammary chain and the left axilla. A chest SPECT/CT was performed to confirm the location of the sentinel nodes. The patient underwent a right mastectomy and left axillary sentinel lymph node biopsy, which showed no evidence of lymphovascular invasion. Combining planar imaging and SPECT/CT techniques can accurately identify sentinel lymph nodes at their new unpredicted location.

  13. Drug Development in Alzheimer’s Disease: The Contribution of PET and SPECT

    PubMed Central

    Declercq, Lieven D.; Vandenberghe, Rik; Van Laere, Koen; Verbruggen, Alfons; Bormans, Guy

    2016-01-01

    Clinical trials aiming to develop disease-altering drugs for Alzheimer’s disease (AD), a neurodegenerative disorder with devastating consequences, are failing at an alarming rate. Poorly defined inclusion-and outcome criteria, due to a limited amount of objective biomarkers, is one of the major concerns. Non-invasive molecular imaging techniques, positron emission tomography and single photon emission (computed) tomography (PET and SPE(C)T), allow visualization and quantification of a wide variety of (patho)physiological processes and allow early (differential) diagnosis in many disorders. PET and SPECT have the ability to provide biomarkers that permit spatial assessment of pathophysiological molecular changes and therefore objectively evaluate and follow up therapeutic response, especially in the brain. A number of specific PET/SPECT biomarkers used in support of emerging clinical therapies in AD are discussed in this review. PMID:27065872

  14. A SPECT imager with synthetic collimation

    NASA Astrophysics Data System (ADS)

    Havelin, Ronan J.; Miller, Brian W.; Barrett, Harrison H.; Furenlid, Lars R.; Murphy, J. M.; Foley, Mark J.

    2013-09-01

    This work outlines the development of a multi-pinhole SPECT system designed to produce a synthetic-collimator image of a small field of view. The focused multi-pinhole collimator was constructed using rapid-prototyping and casting techniques. The collimator projects the field of view through forty-six pinholes when the detector is adjacent to the collimator. The detector is then moved further from the collimator to increase the magnification of the system. The amount of pinhole-projection overlap increases with the system magnification. There is no rotation in the system; a single tomographic angle is used in each system configuration. The maximum-likelihood expectation-maximization (MLEM) algorithm is implemented on graphics processing units to reconstruct the object in the field of view. Iterative reconstruction algorithms, such as MLEM, require an accurate model of the system response. For each system magnification, a sparsely-sampled system response is measured by translating a point source through a grid encompassing the field of view. The pinhole projections are individually identified and associated with their respective apertures. A 2D elliptical Gaussian model is applied to the pinhole projections on the detector. These coefficients are associated with the object-space location of the point source, and a finely-sampled system matrix is interpolated. Simulations with a hot-rod phantom demonstrate the efficacy of combining low-resolution non-multiplexed data with high-resolution multiplexed data to produce high-resolution reconstructions.

  15. Corrective 111 In Capromab Pendetide SPECT Image Reconstruction Methods for Improved Detection of Recurrent Prostate Cancer

    DTIC Science & Technology

    2006-06-01

    with compensation for attenuation and detector response (OSAD). The results in pink are from 25% lesion contrast with respect to background and the...Trans. Nucl. Sci., 1980. NS-27(3): p. 1137-1153. 10. Jaszczak, R.J., C.E. Floyd , Jr., and R.E. Coleman, Scatter Compensation Techniques For SPECT

  16. Small-animal SPECT and SPECT/CT: application in cardiovascular research

    PubMed Central

    Golestani, Reza; Wu, Chao; Tio, René A.; Zeebregts, Clark J.; Petrov, Artiom D.; Beekman, Freek J.; Dierckx, Rudi A. J. O.; Slart, Riemer H. J. A.

    2010-01-01

    Preclinical cardiovascular research using noninvasive radionuclide and hybrid imaging systems has been extensively developed in recent years. Single photon emission computed tomography (SPECT) is based on the molecular tracer principle and is an established tool in noninvasive imaging. SPECT uses gamma cameras and collimators to form projection data that are used to estimate (dynamic) 3-D tracer distributions in vivo. Recent developments in multipinhole collimation and advanced image reconstruction have led to sub-millimetre and sub-half-millimetre resolution SPECT in rats and mice, respectively. In this article we review applications of microSPECT in cardiovascular research in which information about the function and pathology of the myocardium, vessels and neurons is obtained. We give examples on how diagnostic tracers, new therapeutic interventions, pre- and postcardiovascular event prognosis, and functional and pathophysiological heart conditions can be explored by microSPECT, using small-animal models of cardiovascular disease. PMID:20069298

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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 pro- vided accurate ranking of the reconstruction methods. We also demonstrated the application of consistency checks to test the no-gold-standard output.

  19. 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.

  20. Quantitative Monte Carlo-based holmium-166 SPECT reconstruction.

    PubMed

    Elschot, Mattijs; Smits, Maarten L J; Nijsen, Johannes F W; Lam, Marnix G E H; Zonnenberg, Bernard A; van den Bosch, Maurice A A J; Viergever, Max A; de Jong, Hugo W A M

    2013-11-01

    Quantitative imaging of the radionuclide distribution is of increasing interest for microsphere radioembolization (RE) of liver malignancies, to aid treatment planning and dosimetry. For this purpose, holmium-166 ((166)Ho) microspheres have been developed, which can be visualized with a gamma camera. The objective of this work is to develop and evaluate a new reconstruction method for quantitative (166)Ho SPECT, including Monte Carlo-based modeling of photon contributions from the full energy spectrum. A fast Monte Carlo (MC) simulator was developed for simulation of (166)Ho projection images and incorporated in a statistical reconstruction algorithm (SPECT-fMC). Photon scatter and attenuation for all photons sampled from the full (166)Ho energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy- and distance-dependent collimator-detector response was modeled using precalculated convolution kernels. Phantom experiments were performed to quantitatively evaluate image contrast, image noise, count errors, and activity recovery coefficients (ARCs) of SPECT-fMC in comparison with those of an energy window-based method for correction of down-scattered high-energy photons (SPECT-DSW) and a previously presented hybrid method that combines MC simulation of photopeak scatter with energy window-based estimation of down-scattered high-energy contributions (SPECT-ppMC+DSW). Additionally, the impact of SPECT-fMC on whole-body recovered activities (A(est)) and estimated radiation absorbed doses was evaluated using clinical SPECT data of six (166)Ho RE patients. At the same noise level, SPECT-fMC images showed substantially higher contrast than SPECT-DSW and SPECT-ppMC+DSW in spheres ≥ 17 mm in diameter. The count error was reduced from 29% (SPECT-DSW) and 25% (SPECT-ppMC+DSW) to 12% (SPECT-fMC). ARCs in five spherical volumes of 1.96-106.21 ml were improved from 32%-63% (SPECT-DSW) and 50%-80% (SPECT-ppMC+DSW) to 76%-103% (SPECT-fMC). Furthermore

  1. Adaptive SPECT imaging with crossed-slit apertures

    NASA Astrophysics Data System (ADS)

    Durko, Heather L.; Furenlid, Lars R.

    2014-09-01

    Preclinical single-photon emission computed tomography (SPECT) is an essential tool for studying the pro-gression, response to treatment, and physiological changes in small animal models of human disease. The wide range of imaging applications is often limited by the static design of many preclinical SPECT systems. We have developed a prototype imaging system that replaces the standard static pinhole aperture with two sets of movable, keel-edged copper-tungsten blades configured as crossed (skewed) slits. These apertures can be positioned independently between the object and detector, producing a continuum of imaging configurations in which the axial and transaxial magnifications are not constrained to be equal. We incorporated a megapixel silicon double-sided strip detector to permit ultrahigh-resolution imaging. We describe the configuration of the adjustable slit aperture imaging system and discuss its application toward adaptive imaging, and reconstruction techniques using an accurate imaging forward model, a novel geometric calibration technique, and a GPU-based ultra-high-resolution reconstruction code.

  2. Adaptive SPECT imaging with crossed-slit apertures

    PubMed Central

    Durko, Heather L.; Furenlid, Lars R.

    2015-01-01

    Preclinical single-photon emission computed tomography (SPECT) is an essential tool for studying the progression, response to treatment, and physiological changes in small animal models of human disease. The wide range of imaging applications is often limited by the static design of many preclinical SPECT systems. We have developed a prototype imaging system that replaces the standard static pinhole aperture with two sets of movable, keel-edged copper-tungsten blades configured as crossed (skewed) slits. These apertures can be positioned independently between the object and detector, producing a continuum of imaging configurations in which the axial and transaxial magnifications are not constrained to be equal. We incorporated a megapixel silicon double-sided strip detector to permit ultrahigh-resolution imaging. We describe the configuration of the adjustable slit aperture imaging system and discuss its application toward adaptive imaging, and reconstruction techniques using an accurate imaging forward model, a novel geometric calibration technique, and a GPU-based ultra-high-resolution reconstruction code. PMID:26190884

  3. [Sensitivity of neurochemical dementia diagnostics in CSF compared to 99mTc-SPECT in Alzheimer's dementia].

    PubMed

    Weih, M; Krinninger, M; Zimmermann, R; Lewczuk, P; Svitek, J; Schaller, G; Degirmenci, U; Richter-Schmidinger, T; Wiltfang, J; Kuwert, T; Kornhuber, J; Schmidt, D

    2009-07-01

    The diagnosis of Alzheimer's dementia is currently changing from a late and exclusion diagnosis towards a pathophysiology-based early and positive diagnosis. Especially advances in neuro-chemical dementia diagnostics in the cerebrospinal fluid (NDD-CSF) and imaging techniques like PET, SPECT or MRI are of particular interest. Unfortunately, many studies investigated only either one or other technique. In the present study 56 patients (average 67.1 years; average mini-mental status test (MMST) 22.2) were examined with the clinical diagnosis of Alzheimer's dementia. All patients both underwent NDD-CSF as well as 99mTc-SPECT. Only the SPECT, but not the NDD-CSF correlated with disease severity. Sensitivity of NDD-CSF was 89 % and SPECT 48 % for all patients and 93 % resp. 61 % for patients with MMST < 24. Below MMST 20 both methods had equal sensitivity. Both diagnostic techniques showed no statistic coherence (p = 0.27), neither after correction for subgroups like disease severity or the APOE genotype. Our results are compatible with the hypothesis that the NDD-CSF reflects beta-amyloid-aggregation and Tau-Protein pathology as a pathophysiologic biomarker. Our results suggest that SPECT is rather a state parameter for the rCBF changes following cortical neurodegeneration.

  4. TOPICAL REVIEW: Small animal SPECT and its place in the matrix of molecular imaging technologies

    NASA Astrophysics Data System (ADS)

    Meikle, Steven R.; Kench, Peter; Kassiou, Michael; Banati, Richard B.

    2005-11-01

    Molecular imaging refers to the use of non-invasive imaging techniques to detect signals that originate from molecules, often in the form of an injected tracer, and observe their interaction with a specific cellular target in vivo. Differences in the underlying physical principles of these measurement techniques determine the sensitivity, specificity and length of possible observation of the signal, characteristics that have to be traded off according to the biological question under study. Here, we describe the specific characteristics of single photon emission computed tomography (SPECT) relative to other molecular imaging technologies. SPECT is based on the tracer principle and external radiation detection. It is capable of measuring the biodistribution of minute (<10-10 molar) concentrations of radio-labelled biomolecules in vivo with sub-millimetre resolution and quantifying the molecular kinetic processes in which they participate. Like some other imaging techniques, SPECT was originally developed for human use and was subsequently adapted for imaging small laboratory animals at high spatial resolution for basic and translational research. Its unique capabilities include (i) the ability to image endogenous ligands such as peptides and antibodies due to the relative ease of labelling these molecules with technetium or iodine, (ii) the ability to measure relatively slow kinetic processes (compared with positron emission tomography, for example) due to the long half-life of the commonly used isotopes and (iii) the ability to probe two or more molecular pathways simultaneously by detecting isotopes with different emission energies. In this paper, we review the technology developments and design tradeoffs that led to the current state-of-the-art in SPECT small animal scanning and describe the position SPECT occupies within the matrix of molecular imaging technologies.

  5. 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.

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

    PubMed

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

    2009-05-07

    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 beta-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 ((99m)Tc, 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.

  7. Simultaneous reconstruction and segmentation for dynamic SPECT imaging

    NASA Astrophysics Data System (ADS)

    Burger, Martin; Rossmanith, Carolin; Zhang, Xiaoqun

    2016-10-01

    This work deals with the reconstruction of dynamic images that incorporate characteristic dynamics in certain subregions, as arising for the kinetics of many tracers in emission tomography (SPECT, PET). We make use of a basis function approach for the unknown tracer concentration by assuming that the region of interest can be divided into subregions with spatially constant concentration curves. Applying a regularised variational framework reminiscent of the Chan-Vese model for image segmentation we simultaneously reconstruct both the labelling functions of the subregions as well as the subconcentrations within each region. Our particular focus is on applications in SPECT with the Poisson noise model, resulting in a Kullback-Leibler data fidelity in the variational approach. We present a detailed analysis of the proposed variational model and prove existence of minimisers as well as error estimates. The latter apply to a more general class of problems and generalise existing results in literature since we deal with a nonlinear forward operator and a nonquadratic data fidelity. A computational algorithm based on alternating minimisation and splitting techniques is developed for the solution of the problem and tested on appropriately designed synthetic data sets. For those we compare the results to those of standard EM reconstructions and investigate the effects of Poisson noise in the data.

  8. Freehand SPECT in low uptake situations

    NASA Astrophysics Data System (ADS)

    Lasser, Tobias; Ziegler, Sibylle I.; Navab, Nassir

    2011-03-01

    3D functional imaging in the operating room can be extremely useful for some procedures like SLN mapping or SLN biopsies. Freehand SPECT is an example of such an imaging modality, combining manually scanned, hand-held 1D gamma detectors with spatial positioning systems in order to reconstruct localized 3D SPECT images, for example in the breast or neck region. Standard series expansion methods are applied together with custom physical models of the acquisition process and custom filtering procedures to perform 3D tomographic reconstruction from sparse, limited-angle and irregularly sampled data. A Freehand SPECT system can easily be assembled on a mobile cart suitable for use in the operating room. This work addresses in particular the problem of objects with low uptake (like sentinel lymph nodes), where reconstruction tends to be difficult due to low signal to noise ratio. In a neck-like phantom study, we show that four simulated nodes of 250 microliter volume with 0.06% respectively 0.03% uptake of a virtual 70MBq injection of Tc99m (the typical activity for SLN procedures at our hospital) in a background of water can be reconstructed successfully using careful filtering procedures in the reconstruction pipeline. Ten independent Freehand SPECT scans of the phantom were performed by several different operators, with an average scan duration of 5.1 minutes. The resulting reconstructions show an average spatial accuracy within voxel dimensions (2.5mm) compared to CT and exhibit correct relative quantification.

  9. SPECT gallium imaging in abdominal lymphoma

    SciTech Connect

    Adcock, K.A.; Friefeld, G.D.; Waldron, J.A. Jr.

    1986-05-01

    A case of non-Hodgkin's lymphoma of the abdomen studied by gallium SPECT imaging is reported. The tomographic slices accurately demonstrated the location of residual disease after chemotherapy in the region of the transverse mesocolon. Previous transmission CT had shown considerable persistent retroperitoneal lymphadenopathy, but was not helpful in determining the presence of viable lymphoma.

  10. Towards personalized interventional SPECT-CT imaging.

    PubMed

    Gardiazabal, José; Esposito, Marco; Matthies, Philipp; Okur, Asli; Vogel, Jakob; Kraft, Silvan; Frisch, Benjamin; Lasser, Tobias; Navab, Nassir

    2014-01-01

    The development of modern robotics and compact imaging detectors allows the transfer of diagnostic imaging modalities to the operating room, supporting surgeons to perform faster and safer procedures. An intervention that currently suffers from a lack of interventional imaging is radioembolization, a treatment for hepatic carcinoma. Currently, this procedure requires moving the patient from an angiography suite for preliminary catheterization and injection to a whole-body SPECT/CT for leakage detection, necessitating a second catheterization back in the angiography suite for the actual radioembolization. We propose an imaging setup that simplifies this procedure using a robotic approach to directly acquire an interventional SPECT/CT in the angiography suite. Using C-arm CT and a co-calibrated gamma camera mounted on a robotic arm, a personalized trajectory of the gamma camera is generated from the C-arm CT, enabling an interventional SPECT reconstruction that is inherently co-registered to the C-arm CT. In this work we demonstrate the feasibility of this personalized interventional SPECT/CT imaging approach in a liver phantom study.

  11. Generating Dynamic System Matrices for Dynamic SPECT

    SciTech Connect

    2011-02-01

    The purpose of the computer program is to generate system matrices that model data acquisition process in dynamic single photon emission computed tomography (SPECT). The application is for the reconstruction of dynamic data from projection measurements that provide the time evolution of activity uptake and wash out in an organ of interest. The measurement of the time activity in the blood and organ tissue provide time-activity curves (TACs) that are used to estimate kinetic parameters. The program provides a correct model of the in vivo spatial and temporal distribution of radioactive in organs. The model accounts for the attenuation of the internal emitting radioactivity, it accounts for the vary point response of the collimators, and correctly models the time variation of the activity in the organs. One important application where the software is being used in a measuring the arterial input function (AIF) in a dynamic SPECT study where the data are acquired from a slow camera rotation. Measurement of the arterial input function (AIF) is essential to deriving quantitative estimates of regional myocardial blood flow using kinetic models. A study was performed to evaluate whether a slowly rotating SPECT system could provide accurate AIF's for myocardial perfusion imaging (MPI). Methods: Dynamic cardiac SPECT was first performed in human subjects at rest using a Phillips Precedence SPECT/CT scanner. Dynamic measurements of Tc-99m-tetrofosmin in the myocardium were obtained using an infusion time of 2 minutes. Blood input, myocardium tissue and liver TACs were estimated using spatiotemporal splines. These were fit to a one-compartment perfusion model to obtain wash-in rate parameters K1. Results: The spatiotemporal 4D ML-EM reconstructions gave more accurate reconstructions that did standard frame-by-frame 3D ML-EM reconstructions. From additional computer simulations and phantom studies, it was determined that a 1 minute infusion with a SPECT system rotation speed

  12. Multimodal imaging with hybrid semiconductor detectors Timepix for an experimental MRI-SPECT system

    NASA Astrophysics Data System (ADS)

    Zajicek, J.; Jakubek, J.; Burian, M.; Vobecky, M.; Fauler, A.; Fiederle, M.; Zwerger, A.

    2013-01-01

    An increasing number of clinical applications are being based on multimodal imaging systems (MIS), including anatomical (CT, MRI) and functional (PET, SPECT) techniques to provide complex information in a single image. CT with one of the scintigraphic methods (PET or SPECT) is nowadays a combination of choice for clinical practice and it is mostly used in cardiography and tumour diagnostics. Combination with MRI is also being implemented as no radiation dose is imparted to the patient and it is possible to gain higher structural resolution of soft tissues (brain imaging). A major disadvantage of such systems is inability to operate scintillators with photomultipliers (used for detection of γ rays) in presence of high magnetic fields. In this work we present the application of the semiconductor pixel detector for SPECT method in combination with MR imaging. We propose a novel approach based on MRI compatible setup with CdTe pixel sensor Timepix and non-conductive collimator. Measurements were performed on high proton-density (PD) phantom (1H) with an embedded radioisotopic source inside the shielded RF coil by MRI animal scanner (4.7 T). Our results pave the way for a combined MRI-SPECT system. The project was performed in the framework of the Medipix Collaboration.

  13. New open-source ictal SPECT analysis method implemented in BioImage Suite.

    PubMed

    Scheinost, Dustin; Teisseyre, Thomas Z; Distasio, Marcello; DeSalvo, Matthew N; Papademetris, Xenophon; Blumenfeld, Hal

    2010-04-01

    Ictal single photon emission computed tomography (SPECT) is a powerful tool for noninvasive seizure localization, but it has been underutilized because of practical challenges, including difficulty in implementing ictal-interictal SPECT difference analysis. We previously validated a freely available utility for this purpose, ictal-interictal subtraction analysis by statistical parametric mapping (SPM) (ISAS). To further simplify and improve the difference imaging technique, we now compare a new algorithm, ISAS BioImage Suite (see http://spect.yale.edu and http://bioimagesuite.org), to the original ISAS method in 13 patients with known seizure localization. We found that ISAS BioImage Suite was in agreement with the original algorithm in all cases for which ISAS correctly identified a single unambiguous region of seizure onset. We also tested for possible effects of scan-order bias in the control group used for the analysis and found no significant effect on the results. These findings establish a simple, validated and objective method for analyzing ictal-interictal SPECT difference images for use in the care of patients with epilepsy.

  14. Improving the count rate performance of a modular cylindrical SPECT system

    SciTech Connect

    Li, Y.J.; Hollinger, E.F.; Liu, J.; Chang, W.

    1996-12-31

    We recently proposed a design of a modular cylindrical cardiac SPECT system. one special feature of this system is an integrated provision for transmission imaging. To meet the clinical demands of obtaining transmission images, this system must be able to achieve a very high count rate (CR). To explore methods for achieving a high CR capability on a modular cylindrical detector system, we have used our existing modular cylindrical brain SPECT system to examine the feasibility of two approaches. First, we use digital-signal-processing (DSP) boards, in parallel, to execute real time position calculations. Second, we use local encoding and triggering circuits to perform analog signal processing, including identifying the detector module and digitizing the pulse signals. The results of our preliminary investigations indicate that applying the multiple-DSP parallel position calculation and local triggering techniques in a modular SPECT system can improve the CR capability significantly. Applying local triggering increased the CR capability by 15% at a CR capability of 200 kcps. Because we have used slow-speed DSP boards during this proof-of-concept testing, we have not yet met the CR requirements for transmission imaging. However, these results indicate that by using state-of-the-art DSP boards the CR capability of this modular SPECT system can be increased to over 300 kcps.

  15. The improved accuracy of planar bone scintigraphy by adding single photon emission computed tomography (SPECT-CT) to detect skeletal metastases from prostate cancer.

    PubMed

    McLoughlin, L C; O'Kelly, F; O'Brien, C; Sheikh, M; Feeney, J; Torreggiani, W; Thornhill, J A

    2016-02-01

    Planar bone scintigraphy (PBS) is a standard radiological technique to detect skeletal metastases from prostate cancer (PC), the addition of SPECT-CT to PBS improves its diagnostic accuracy. The aim of this study was to assess the additional value of targeted SPECT-CT with PBS in detecting skeletal metastasis form prostate cancer, considering resource implications in an Irish hospital setting. 54 PC patients with increased radiotracer uptake on PBS were retrospectively recruited from 2012 to 2013. All underwent targeted evaluation with SPECT-CT. PBS and SPECT-CT images were reviewed by two nuclear medicine radiologists and reported independently. The final diagnosis was made based on the CT finding corresponding to the area of radiotracer uptake. The mean age was 70.9 years (48-88 years) and median PSA at presentation was 13.9 ng/ml (4.2-215 ng/ml). 68.5 % (n = 37) men received treatment for PC while 31.5 % (n = 17) patients had not received treatment prior to PBS. 164 areas of increased radiotracer uptake were identified on PBS; 13 areas were characterised as metastatic on SPECT-CT; iliac bone (n = 3), ribs (n = 1), skull (n = 2), sacrum (n = 1), ischium (n = 1), femur (n = 3), thoracic spine (n = 1) and cervical spine (n = 1). 151 areas were characterised as benign on SPECT-CT. One area of increased radiotracer uptake in the ribs was subsequently described as indeterminate after evaluation with SPECT-CT. SPECT-CT improves the diagnostic accuracy of PBS in detecting skeletal metastasis from PC and is superior to PBS alone in differentiating benign from malignant lesions. Notwithstanding resource implications of increased cost, specialist equipment and specialist manpower hours; we recommend the use of SPECT-CT in conjunction with PBS for targeted evaluation of suspicious bony lesions in this cohort of patients.

  16. Combining FDG-PET and 99mTc-SPECT to predict functional outcome after coronary artery bypass surgery.

    PubMed

    Lehtinen, Miia; Schildt, Jukka; Ahonen, Aapo; Nikkinen, Päivi; Lauerma, Kirsi; Sinisalo, Juha; Kankuri, Esko; Vento, Antti; Pätilä, Tommi; Harjula, Ari

    2015-09-01

    Single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are suggested to improve clinical decision-making in ischaemic cardiomyopathy. Here, we present a unique cohort of patients who underwent nuclear medicine studies and cardiac magnetic resonance imaging (MRI) both before and 1 year after coronary artery bypass (CABG) surgery to assess benefit from surgery. Before CABG, we applied three quantitative techniques using (18)F-fluorodeoxyglucose-PET and (99m)technetium-tetrofosmin-SPECT with a software tool to measure defects with hypoperfused but viable and non-viable myocardium in 15 patients. One method used solely PET, two others combined PET and SPECT at different thresholds. As a reference, we used change in left-ventricular (LV) function and volume by MRI. Preoperatively, ischaemic but viable areas detected by the method with a 10% threshold combining PET-SPECT and the PET-only method correlated significantly with preoperative regional wall thickening (WT; P = 0.03 and P = 0.005, respectively). When compared with global functional outcome (change in LV ejection fraction) and LV remodelling (change in end-diastolic volume) 1 year postoperatively, no correlation appeared with preoperative PET- or PET-SPECT-derived viable or non-viable tissue. Neither was any correlation observable between local change in WT and local preoperative defect size evaluated by any of these three methods. Preoperatively, PET and PET-SPECT with 10% threshold detected dysfunctional myocardium, but all analysis methods failed to predict 1-year functional outcome assessed by MRI. In patients with three-vessel disease and heart failure, SPECT perfusion and PET viability study results show substantial heterogeneity; this should be considered when selecting patients for revascularization. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  17. High-Efficiency SPECT MPI: Comparison of Automated Quantification, Visual Interpretation, and Coronary Angiography

    PubMed Central

    Duvall, W. Lane; Slomka, Piotr J.; Gerlach, Jim R.; Sweeny, Joseph M.; Baber, Usman; Croft, Lori B.; Guma, Krista A.; George, Titus; Henzlova, Milena J.

    2013-01-01

    Background Recently introduced high-efficiency (HE) SPECT cameras with solid-state CZT detectors have been shown to decrease imaging time and reduce radiation exposure to patients. An automated, computer derived quantification of HE MPI has been shown to correlate well with coronary angiography on one HE SPECT camera system (D-SPECT), but has not been compared to visual interpretation on any of the HE SPECT platforms. Methods Patients undergoing a clinically indicated Tc-99m sestamibi HE SPECT (GE Discovery 530c with supine and prone imaging) study over a one year period followed by a coronary angiogram within 2 months were included. Only patients with a history of CABG surgery were excluded. Both MPI studies and coronary angiograms were reinterpreted by blinded readers. One hundred and twenty two very low (risk of CAD < 5%) or low (risk of CAD < 10%) likelihood subjects with normal myocardial perfusion were used to create normal reference limits. Computer derived quantification of the total perfusion deficit (TPD) at stress and rest was obtained with QPS software. The visual and automated MPI quantification were compared to coronary angiography (≥ 70% luminal stenosis) by receiver operating curve (ROC) analysis. Results Of the 3,111 patients who underwent HE SPECT over a one year period, 160 patients qualified for the correlation study (66% male, 52% with a history of CAD). The ROC area under the curve (AUC) was similar for both the automated and visual interpretations using both supine only and combined supine and prone images (0.69-0.74). Using thresholds determined from sensitivity and specificity curves, the automated reads showed higher specificity (59-67% versus 27-60%) and lower sensitivity (71-72% versus 79-93%) than the visual reads. By including prone images sensitivity decreased slightly but specificity increased for both. By excluding patients with known CAD and cardiomyopathies, AUC and specificity increased for both techniques (0.72-0.82). The use

  18. Integration of SimSET photon history generator in GATE for efficient Monte Carlo simulations of pinhole SPECT

    PubMed Central

    Chen, Chia-Lin; Wang, Yuchuan; Lee, Jason J. S.; Tsui, Benjamin M. W.

    2008-01-01

    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 ∼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. PMID:18697552

  19. Tl-201 and Tc-99m-Sestamibi SPECT for brain tumor detection: Comparison using MRI coregistration

    SciTech Connect

    Darcourt, J.; Itti, L.; Chang, L.

    1994-05-01

    Tl-201 (Tl) brain SPECT has been validated for the differential diagnosis of high versus low grade gliomas and recurrence versus radiation necrosis. We compared this technique to Tc-99m-Sestamibi (MIBI) SPECT in 9 patients (pts) with brain tumors using MRI coregistration. Pts were injected with 4 mCi of Tl and brain SPECT was performed using a dedicated brain system. This was immediately following by an injection of 20 mCi of MIBI and a brain SPECT using the same camera and with the pt in the same position. Four pts were studied for the diagnosis of radiation necrosis vs. tumor recurrence (2 had biopsy proven recurrence); 5 pts were studied for primary tumor evaluation: 2 meningiomas, 1 oligodendroglioma, 1 low-grade astrocytoma, 1 cysticercosis. Coregistration was performed for every pt by 3D surface fitting of the inner skull MIBI contour to the MRI brain surface extracted automatically. ROIs were drawn on the MRI and applied to the coregistered MIBI and Tl images for tumor to non-tumor ratios T/NT calculations. There was a tight correlation between MIBI and Tl T/NT (r-0.96) and a 1.5 threshold separated radiation necrosis from recurrence and low from high grade primary tumors. Therefore, the data already available on Tl brain tumor imaging can be used with MIBI SPECT with the advantage of a better image quality (2.5 to 4 times more counts).

  20. 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.

  1. 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

  2. Skeletal muscle satellite cell migration to injured tissue measured with 111In-oxine and high-resolution SPECT imaging

    PubMed Central

    Elster, Jennifer L.; Rathbone, Christopher R.; Liu, Zhonglin; Liu, Xiasong; Barrett, Harrison H.; Rhoads, Robert P.; Allen, Ronald E.

    2014-01-01

    The delivery of adult skeletal muscle stem cells, called satellite cells, to several injured muscles via the circulation would be useful, however, an improved understanding of cell fate and biodistribution following their delivery is important for this goal to be achieved. The objective of this study was to evaluate the ability of systemically delivered satellite cells to home to injured skeletal muscle using single-photon emission computed tomography (SPECT) imaging of 111In-labeled satellite cells. Satellite cells labeled with 111In-oxine and green fluorescent protein (GFP) were injected intravenously after bupivicaine-induced injury to the tibialis anterior muscle. Animals were imaged with a high-resolution SPECT system called FastSPECT II for up to 7 days after transplantation. In vivo FastSPECT II imaging demonstrated a three to five-fold greater number of transplanted satellite cells in bupivicaine-injured muscle as compared to un-injured muscle after transplantation; a finding that was verified through autoradiograph analysis and quantification of GFP expression. Satellite cells also accumulated in other organs including the lung, liver, and spleen, as determined by biodistribution measurements. These data support the ability of satellite cells to home to injured muscle and support the use of SPECT and autoradiograph imaging techniques to track systemically transplanted 111In labeled satellite cells in vivo, and suggest their homing may be improved by reducing their entrapment in filter organs. PMID:24190365

  3. Assessment of the sources of error affecting the quantitative accuracy of SPECT imaging in small animals

    NASA Astrophysics Data System (ADS)

    Hwang, Andrew B.; Franc, Benjamin L.; Gullberg, Grant T.; Hasegawa, Bruce H.

    2008-05-01

    Small animal SPECT imaging systems have multiple potential applications in biomedical research. Whereas SPECT data are commonly interpreted qualitatively in a clinical setting, the ability to accurately quantify measurements will increase the utility of the SPECT data for laboratory measurements involving small animals. In this work, we assess the effect of photon attenuation, scatter and partial volume errors on the quantitative accuracy of small animal SPECT measurements, first with Monte Carlo simulation and then confirmed with experimental measurements. The simulations modeled the imaging geometry of a commercially available small animal SPECT system. We simulated the imaging of a radioactive source within a cylinder of water, and reconstructed the projection data using iterative reconstruction algorithms. The size of the source and the size of the surrounding cylinder were varied to evaluate the effects of photon attenuation and scatter on quantitative accuracy. We found that photon attenuation can reduce the measured concentration of radioactivity in a volume of interest in the center of a rat-sized cylinder of water by up to 50% when imaging with iodine-125, and up to 25% when imaging with technetium-99m. When imaging with iodine-125, the scatter-to-primary ratio can reach up to approximately 30%, and can cause overestimation of the radioactivity concentration when reconstructing data with attenuation correction. We varied the size of the source to evaluate partial volume errors, which we found to be a strong function of the size of the volume of interest and the spatial resolution. These errors can result in large (>50%) changes in the measured amount of radioactivity. The simulation results were compared with and found to agree with experimental measurements. The inclusion of attenuation correction in the reconstruction algorithm improved quantitative accuracy. We also found that an improvement of the spatial resolution through the use of resolution

  4. Microdialysis and SPECT measurements of amphetamine-induced dopamine release in nonhuman primates.

    PubMed

    Laruelle, M; Iyer, R N; al-Tikriti, M S; Zea-Ponce, Y; Malison, R; Zoghbi, S S; Baldwin, R M; Kung, H F; Charney, D S; Hoffer, P B; Innis, R B; Bradberry, C W

    1997-01-01

    The competition between endogenous transmitters and radiolabeled ligands for in vivo binding to neuroreceptors might provide a method to measure endogenous transmitter release in the living human brain with noninvasive techniques such as positron emission tomography (PET) or single photon emission computerized tomography (SPECT). In this study, we validated the measure of amphetamine-induced dopamine release with SPECT in nonhuman primates. Microdialysis experiments were conducted to establish the dose-response curve of amphetamine-induced dopamine release and to document how pretreatment with the dopamine depleter alpha-methyl-para-tyrosine (alpha MPT) affects this response. SPECT experiments were performed with two iodinated benzamides, [123I]IBZM and [123I]IBF, under sustained equilibrium condition. Both radio-tracers are specific D2 antagonists, but the affinity of [123I]IBZM (KD-0.4 nM) is lower than that of [123I]IBF (KD 0.1 nM). With both tracers, we observed a prolonged reduction in binding to D2 receptors following amphetamine injection. [123I]IBZM binding to D2 receptors was more affected than [123I]IBF by high doses of amphetamine, indicating that a lower affinity increases the vulnerability of a tracer to endogenous competition. With [123I]IBZM, we observed an excellent correlation between reduction of D2 receptor binding measured with SPECT and peak dopamine release measured with microdialysis after various doses of amphetamine. Pretreatment with alpha MPT significantly reduced the effect of amphetamine on [123I]IBZM binding to D2 receptors, confirming that this effect was mediated by intrasynaptic dopamine release. Together, these results validate the use of this SPECT paradigm as a noninvasive measurement of intrasynaptic dopamine release in the living brain.

  5. Assessment of the sources of error affecting the quantitative accuracy of SPECT imaging in small animals

    SciTech Connect

    Joint Graduate Group in Bioengineering, University of California, San Francisco and University of California, Berkeley; Department of Radiology, University of California; Gullberg, Grant T; Hwang, Andrew B.; Franc, Benjamin L.; Gullberg, Grant T.; Hasegawa, Bruce H.

    2008-02-15

    Small animal SPECT imaging systems have multiple potential applications in biomedical research. Whereas SPECT data are commonly interpreted qualitatively in a clinical setting, the ability to accurately quantify measurements will increase the utility of the SPECT data for laboratory measurements involving small animals. In this work, we assess the effect of photon attenuation, scatter and partial volume errors on the quantitative accuracy of small animal SPECT measurements, first with Monte Carlo simulation and then confirmed with experimental measurements. The simulations modeled the imaging geometry of a commercially available small animal SPECT system. We simulated the imaging of a radioactive source within a cylinder of water, and reconstructed the projection data using iterative reconstruction algorithms. The size of the source and the size of the surrounding cylinder were varied to evaluate the effects of photon attenuation and scatter on quantitative accuracy. We found that photon attenuation can reduce the measured concentration of radioactivity in a volume of interest in the center of a rat-sized cylinder of water by up to 50percent when imaging with iodine-125, and up to 25percent when imaging with technetium-99m. When imaging with iodine-125, the scatter-to-primary ratio can reach up to approximately 30percent, and can cause overestimation of the radioactivity concentration when reconstructing data with attenuation correction. We varied the size of the source to evaluate partial volume errors, which we found to be a strong function of the size of the volume of interest and the spatial resolution. These errors can result in large (>50percent) changes in the measured amount of radioactivity. The simulation results were compared with and found to agree with experimental measurements. The inclusion of attenuation correction in the reconstruction algorithm improved quantitative accuracy. We also found that an improvement of the spatial resolution through the

  6. Indium-Labeling of siRNA for Small Animal SPECT Imaging

    PubMed Central

    Jones, Steven; Merkel, Olivia

    2016-01-01

    Ever since the discovery of RNA interference (RNAi), therapeutic delivery of siRNA has attracted a lot of interest. However, due to the nature and structure of siRNA, a carrier is needed for any mode of systemic treatment. Furthermore, specific imaging techniques are required to trace where the deposition of the siRNA occurs throughout the body after treatment. Tracking in vivo siRNA biodistribution allows understanding and interpreting therapeutics effects and side effects. A great advantage of noninvasive imaging techniques such as SPECT imaging is that several time points can be assessed in the same subject. Thus, the time course of biodistribution or metabolic processes can be followed. Therefore, we have described an approach to modify siRNA with a DTPA (Diethylene Triamine Pentaacetic Acid) chelator in order to utilize an indium labeled siRNA for SPECT imaging. Here, we explain the details of the labeling and purification procedures. PMID:26530916

  7. Indium-Labeling of siRNA for Small Animal SPECT Imaging.

    PubMed

    Jones, Steven; Merkel, Olivia

    2016-01-01

    Ever since the discovery of RNA interference (RNAi), therapeutic delivery of siRNA has attracted a lot of interest. However, due to the nature and structure of siRNA, a carrier is needed for any mode of systemic treatment. Furthermore, specific imaging techniques are required to trace where the deposition of the siRNA occurs throughout the body after treatment. Tracking in vivo siRNA biodistribution allows understanding and interpreting therapeutics effects and side effects. A great advantage of noninvasive imaging techniques such as SPECT imaging is that several time points can be assessed in the same subject. Thus, the time course of biodistribution or metabolic processes can be followed. Therefore, we have described an approach to modify siRNA with a DTPA (Diethylene Triamine Pentaacetic Acid) chelator in order to utilize an indium labeled siRNA for SPECT imaging. Here, we explain the details of the labeling and purification procedures.

  8. The clinical impact of SPECT/PET co-registration with MRI in patients with brain tumors

    SciTech Connect

    Macapinlac, H.A.; Scott, A.M.; Zhang, J.J.

    1994-05-01

    We wanted to evaluate the clinical impact of co-registering SPECT and PET images with MRI (Gd-DTPA) in brain tumor patients. 81 patients with known or suspected brain tumors had 168 SPECT and/or PET scans which were difficult to interpret were coregistered with MRI. A modified Pellizari/Chen surface matching algorithm was used to fit the SPECT/PET and MR images. Impact of the technique on interpretation of the scans was defined as (A) no effect, (B) moderate effect (better localize abnormal uptake to suspected tumor and distinguish normal activity from tumor), (C) basis for final interpretation (distinguish tumor from necrosis, localize biopsy site, find occult tumor, grading of tumor). Impact on patient management was defined as (A) no effect, (B) altered diagnostic/treatment decision (continuation of conservative care, or justify chemo or radiation), (C) basis for treatment (direct biopsy, surgery, and/or radiation).

  9. Systolic and diastolic assessment by 3D-ASM segmentation of gated-SPECT Studies: a comparison with MRI

    NASA Astrophysics Data System (ADS)

    Tobon-Gomez, C.; Bijnens, B. H.; Huguet, M.; Sukno, F.; Moragas, G.; Frangi, A. F.

    2009-02-01

    Gated single photon emission tomography (gSPECT) is a well-established technique used routinely in clinical practice. It can be employed to evaluate global left ventricular (LV) function of a patient. The purpose of this study is to assess LV systolic and diastolic function from gSPECT datasets in comparison with cardiac magnetic resonance imaging (CMR) measurements. This is achieved by applying our recently implemented 3D active shape model (3D-ASM) segmentation approach for gSPECT studies. This methodology allows for generation of 3D LV meshes for all cardiac phases, providing volume time curves and filling rate curves. Both systolic and diastolic functional parameters can be derived from these curves for an assessment of patient condition even at early stages of LV dysfunction. Agreement of functional parameters, with respect to CMR measurements, were analyzed by means of Bland-Altman plots. The analysis included subjects presenting either LV hypertrophy, dilation or myocardial infarction.

  10. PET and SPECT in the management of lung cancer.

    PubMed

    Sarinas, Priscilla S A; Chitkara, Rajinder K

    2002-07-01

    Lung cancer is the leading cause of cancer deaths in men and women. Most recently in 2001, the Health Care Financing Administration has expanded Medicare coverage for positron emission tomography (PET) to include the diagnosis, staging, and restaging of lung cancer. This review discusses the current metabolic imaging techniques, including the role of PET, single-photon emission computed tomography (SPECT), and the new hybrid PET in the diagnosis, staging, and treatment of lung cancer. The technological advantages, disadvantages, and benefits are compared. PET has the highest detection efficiency than gamma camera based devices. PET when merged with computed tomography (CT) forms the powerful hybrid PET-CT system, capable both of metabolic and anatomic imaging. Clinical imaging pathways based on these newer modalities for the management of lung cancer are proposed. Technological advances in metabolic imaging linked with therapy driven protocols and outcomes may further provide cutting edge modalities that positively impact on dismal lung cancer mortality statistics.

  11. Technological Development and Advances in SPECT/CT

    PubMed Central

    Seo, Youngho; Aparici, Carina Mari; Hasegawa, Bruce H

    2010-01-01

    SPECT/CT has emerged over the past decade as a means of correlating anatomical information from CT with functional information from SPECT. The integration of SPECT and CT in a single imaging device facilitates anatomical localization of the radiopharmaceutical to differentiate physiological uptake from that associated with disease and patient-specific attenuation correction to improve the visual quality and quantitative accuracy of the SPECT image. The first clinically available SPECT/CT systems performed emission-transmission imaging using a dual-headed SPECT camera and a low-power x-ray CT sub-system. Newer SPECT/CT systems are available with high-power CT sub-systems suitable for detailed anatomical diagnosis, including CT coronary angiography and coronary calcification that can be correlated with myocardial perfusion measurements. The high-performance CT capabilities also offer the potential to improve compensation of partial volume errors for more accurate quantitation of radionuclide measurement of myocardial blood flow and other physiological processes and for radiation dosimetry for radionuclide therapy. In addition, new SPECT technologies are being developed that significantly improve the detection efficiency and spatial resolution for radionuclide imaging of small organs including the heart, brain, and breast, and therefore may provide new capabilities for SPECT/CT imaging in these important clinical applications. PMID:18396178

  12. Functional neuroimaging in epilepsy: FDG PET and ictal SPECT.

    PubMed Central

    Lee, D. S.; Lee, S. K.; Lee, M. C.

    2001-01-01

    Epileptogenic zones can be localized by F-18 fluorodeoxyglucose positron emission tomography (FDG PET) and ictal single-photon emission computed tomography(SPECT). In medial temporal lobe epilepsy, the diagnostic sensitivity of FDG PET or ictal SPECT is excellent, however, the sensitivity of MRI is so high that the incremental sensitivity by FDG PET or ictal SPECT has yet to be proven. When MRI findings are ambiguous or normal, or discordant with those of ictal EEG, FDG PET and ictal SPECT are helpful for localization without the need for invasive ictal EEG. In neocortical epilepsy, the sensitivities of FDG PET or ictal SPECT are fair. However, because almost a half of the patients are normal on MRI, FDG PET and ictal SPECT are helpful for localization or at least for lateralization in these non-lesional epilepsies in order to guide the subdural insertion of electrodes. Interpretation of FDG PET has been recently advanced by voxel-based analysis and automatic volume of interest analysis based on a population template. Both analytical methods confirmed the performance of previous visual interpretation results. Ictal SPECT was analyzed using subtraction methods(coregistered to MRI) and voxel-based analysis. Rapidity of injection of tracers, HMPAO versus ECD, and repeated ictal SPECT, which remain the technical issues of ictal SPECT, are detailed. PMID:11748346

  13. Silicon Detectors for PET and SPECT

    NASA Astrophysics Data System (ADS)

    Cochran, Eric R.

    Silicon detectors use state-of-the-art electronics to take advantage of the semiconductor properties of silicon to produce very high resolution radiation detectors. These detectors have been a fundamental part of high energy, nuclear, and astroparticle physics experiments for decades, and they hold great potential for significant gains in both PET and SPECT applications. Two separate prototype nuclear medicine imaging systems have been developed to explore this potential. Both devices take advantage of the unique properties of high resolution pixelated silicon detectors, designed and developed as part of the CIMA collaboration and built at The Ohio State University. The first prototype is a Compton SPECT imaging system. Compton SPECT, also referred to as electronic collimation, is a fundamentally different approach to single photon imaging from standard gamma cameras. It removes the inherent coupling of spatial resolution and sensitivity in mechanically collimated systems and provides improved performance at higher energies. As a result, Compton SPECT creates opportunities for the development of new radiopharmaceuticals based on higher energy isotopes as well as opportunities to expand the use of current isotopes such as 131I due to the increased resolution and sensitivity. The Compton SPECT prototype consists of a single high resolution silicon detector, configured in a 2D geometry, in coincidence with a standard NaI scintillator detector. Images of point sources have been taken for 99mTc (140 keV), 131I (364keV), and 22Na (511 keV), demonstrating the performance of high resolution silicon detectors in a Compton SPECT system. Filtered back projection image resolutions of 10 mm, 7.5 mm, and 6.7 mm were achieved for the three different sources respectively. The results compare well with typical SPECT resolutions of 5-15 mm and validate the claims of improved performance in Compton SPECT imaging devices at higher source energies. They also support the potential of

  14. Automated coregistration and statistical analyses of SPECT brain images

    SciTech Connect

    Gong, W.; Devous, M.D.

    1994-05-01

    Statistical analyses of SPECT image data often require highly accurate image coregistration. Several image coregistration algorithms have been developed. The Pellizari algorithm (PA) uses the Powell technique to estimate transformation parameters between the {open_quotes}head{close_quotes} (model) and {open_quotes}hat{close_quotes} (images to be registered). Image normalization and good initial transformation parameters heavily affect the accuracy and speed of convergence of the PA. We have explored various normalization methods and found a simple technique that avoids most artificial edge effects and minimizes blurring of useful edges. We have tested the effects on accuracy and convergence speed of the PA caused by different initial transformation parameters. From these data, a modified PA was integrated into an automated coregistration system for SPECT brain images on the PRISM 3000S under X Windows. The system yields an accuracy of approximately 2 mm between model and registered images, and employs minimal user intervention through a simple graphic user interface. Data are automatically resliced, normalized and coregistered, with the user choosing only the slice range for inclusion and two initial transformation parameters (under computer-aided guidance). Coregistration is accomplished (converges) in approximately 8 min for a 128 x 128 x 128 set of 2 mm{sup 3} voxels. The complete process (editing, reslicing, normalization, coregistration) takes about 20 min. We have also developed automated 3-dimensional parametric images ({open_quotes}t{close_quotes}, {open_quotes}z{close_quotes}, and subtraction images) from coregistered data sets for statistical analyses. Data are compared against a coregistered normal control group (N = 50) distributed in age and gender for matching against subject samples.

  15. New Approaches in SPECT Breast Imaging

    DTIC Science & Technology

    2005-07-01

    the use of their breast and torso phantoms. The software package, "SPECTER", developed by Tim Turkington, was used to analyze and display the phantom...breast images. The software package, "SPECT-MAP", developed by James Bowsher, was used for reconstructions. VI. REFERENCES [1] Tornai MP, Bowsher JE...based software . and standard errors of the mean. No attenuation or scatter corrections were taken into account in For a given statistical ensemble of

  16. Reconstruction of dynamic gated cardiac SPECT

    SciTech Connect

    Jin Mingwu; Yang Yongyi; King, Michael A.

    2006-11-15

    In this paper we propose an image reconstruction procedure which aims to unify gated single photon emission computed tomography (SPECT) and dynamic SPECT into a single method. We divide the cardiac cycle into a number of gate intervals as in gated SPECT, but treat the tracer distribution for each gate as a time-varying signal. By using both dynamic and motion-compensated temporal regularization, our reconstruction procedure will produce an image sequence that shows both cardiac motion and time-varying tracer distribution simultaneously. To demonstrate the proposed reconstruction method, we simulated gated cardiac perfusion imaging using the gated mathematical cardiac-torso (gMCAT) phantom with Tc99m-Teboroxime as the imaging agent. Our results show that the proposed method can produce more accurate reconstruction of gated dynamic images than independent reconstruction of individual gate frames with spatial smoothness alone. In particular, our results show that the former could improve the contrast to noise ratio of a simulated perfusion defect by as much as 100% when compared to the latter.

  17. SPECT and PET Imaging of Meningiomas

    PubMed Central

    Valotassiou, Varvara; Leondi, Anastasia; Angelidis, George; Psimadas, Dimitrios; Georgoulias, Panagiotis

    2012-01-01

    Meningiomas arise from the meningothelial cells of the arachnoid membranes. They are the most common primary intracranial neoplasms and represent about 20% of all intracranial tumors. They are usually diagnosed after the third decade of life and they are more frequent in women than in men. According to the World Health Organization (WHO) criteria, meningiomas can be classified into grade I meningiomas, which are benign, grade II (atypical) and grade III (anaplastic) meningiomas, which have a much more aggressive clinical behaviour. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are routinely used in the diagnostic workup of patients with meningiomas. Molecular Nuclear Medicine Imaging with Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) could provide complementary information to CT and MRI. Various SPECT and PET tracers may provide information about cellular processes and biological characteristics of meningiomas. Therefore, SPECT and PET imaging could be used for the preoperative noninvasive diagnosis and differential diagnosis of meningiomas, prediction of tumor grade and tumor recurrence, response to treatment, target volume delineation for radiation therapy planning, and distinction between residual or recurrent tumour from scar tissue. PMID:22623896

  18. SPECT and PET imaging of meningiomas.

    PubMed

    Valotassiou, Varvara; Leondi, Anastasia; Angelidis, George; Psimadas, Dimitrios; Georgoulias, Panagiotis

    2012-01-01

    Meningiomas arise from the meningothelial cells of the arachnoid membranes. They are the most common primary intracranial neoplasms and represent about 20% of all intracranial tumors. They are usually diagnosed after the third decade of life and they are more frequent in women than in men. According to the World Health Organization (WHO) criteria, meningiomas can be classified into grade I meningiomas, which are benign, grade II (atypical) and grade III (anaplastic) meningiomas, which have a much more aggressive clinical behaviour. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are routinely used in the diagnostic workup of patients with meningiomas. Molecular Nuclear Medicine Imaging with Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) could provide complementary information to CT and MRI. Various SPECT and PET tracers may provide information about cellular processes and biological characteristics of meningiomas. Therefore, SPECT and PET imaging could be used for the preoperative noninvasive diagnosis and differential diagnosis of meningiomas, prediction of tumor grade and tumor recurrence, response to treatment, target volume delineation for radiation therapy planning, and distinction between residual or recurrent tumour from scar tissue.

  19. SPECT detectors: the Anger Camera and beyond.

    PubMed

    Peterson, Todd E; Furenlid, Lars R

    2011-09-07

    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 sodium iodide 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.

  20. 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

  1. SPECT detectors: the Anger Camera and beyond

    NASA Astrophysics Data System (ADS)

    Peterson, Todd E.; Furenlid, Lars R.

    2011-09-01

    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 sodium iodide 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.

  2. Combining SPECT medical imaging and computational fluid dynamics for analyzing blood and dialysate flow in hemodialyzers.

    PubMed

    Eloot, S; D'Asseler, Y; De Bondt, P; Verdonck, R

    2005-07-01

    For a better insight in dialyzer efficiency with respect to local mass transport in a low flux dialyzer (Fresenius F6HPS), blood and dialysate flow distributions were visualized with computational fluid dynamic (CFD) simulations, which were validated with single photon emission computed tomography (SPECT) imaging. To visualize blood-side flow while avoiding transport through the fiber membrane, a bolus of 99m-Technetium labeled MAA (Macro Aggregated Albumin) was injected in the flow using an electronic valve. Water was used to simulate blood, but flow rate was adjusted according to laws of dynamic similarity to account for the viscosity difference (factor 2.75). For the visualization of dialysate flow, a bolus of 99m-Technetium labeled DMSA (Dimercaptosuccinic Acid) was injected, while pressurized air in the blood compartment avoided transmembrane flow. For each test series, 3D acquisitions were made on a two respectively three-headed SPECT camera. By evaluating the images at different time steps, dynamic 3D intensity plots were obtained, which were further used to derive local flow velocities. Additionally, three-dimensional CFD models were developed for simulating the overall blood and dialysate flow, respectively. In both models,the whole fiber compartment was defined as a porous medium with overall axial and radial permeability derived theoretically and from in vitro tests. With the imaging as well as with the computational technique, a homogeneous blood flow distribution was found, while vortices and fluid stagnation were observed in the dialyzer inlet manifold. The non-homogeneous dialysate distribution, as found with SPECT imaging, implies the occurrence of non-efficient sites with respect to mass transfer. The discrepancy between the dialysate results of both techniques indicated that the assumption of a constant fiber bundle permeability in the CFD model was too optimistic. In conclusion, medical imaging techniques like SPECT are very helpful to validate

  3. Development and optimization of SPECT gated blood pool cluster analysis for the prediction of CRT outcome.

    PubMed

    Lalonde, Michel; Wells, R Glenn; Birnie, David; Ruddy, Terrence D; Wassenaar, Richard

    2014-07-01

    Phase analysis of single photon emission computed tomography (SPECT) radionuclide angiography (RNA) has been investigated for its potential to predict the outcome of cardiac resynchronization therapy (CRT). However, phase analysis may be limited in its potential at predicting CRT outcome as valuable information may be lost by assuming that time-activity curves (TAC) follow a simple sinusoidal shape. A new method, cluster analysis, is proposed which directly evaluates the TACs and may lead to a better understanding of dyssynchrony patterns and CRT outcome. Cluster analysis algorithms were developed and optimized to maximize their ability to predict CRT response. About 49 patients (N = 27 ischemic etiology) received a SPECT RNA scan as well as positron emission tomography (PET) perfusion and viability scans prior to undergoing CRT. A semiautomated algorithm sampled the left ventricle wall to produce 568 TACs from SPECT RNA data. The TACs were then subjected to two different cluster analysis techniques, K-means, and normal average, where several input metrics were also varied to determine the optimal settings for the prediction of CRT outcome. Each TAC was assigned to a cluster group based on the comparison criteria and global and segmental cluster size and scores were used as measures of dyssynchrony and used to predict response to CRT. A repeated random twofold cross-validation technique was used to train and validate the cluster algorithm. Receiver operating characteristic (ROC) analysis was used to calculate the area under the curve (AUC) and compare results to those obtained for SPECT RNA phase analysis and PET scar size analysis methods. Using the normal average cluster analysis approach, the septal wall produced statistically significant results for predicting CRT results in the ischemic population (ROC AUC = 0.73;p < 0.05 vs. equal chance ROC AUC = 0.50) with an optimal operating point of 71% sensitivity and 60% specificity. Cluster analysis results were

  4. Development and optimization of SPECT gated blood pool cluster analysis for the prediction of CRT outcome

    SciTech Connect

    Lalonde, Michel Wassenaar, Richard; Wells, R. Glenn; Birnie, David; Ruddy, Terrence D.

    2014-07-15

    Purpose: Phase analysis of single photon emission computed tomography (SPECT) radionuclide angiography (RNA) has been investigated for its potential to predict the outcome of cardiac resynchronization therapy (CRT). However, phase analysis may be limited in its potential at predicting CRT outcome as valuable information may be lost by assuming that time-activity curves (TAC) follow a simple sinusoidal shape. A new method, cluster analysis, is proposed which directly evaluates the TACs and may lead to a better understanding of dyssynchrony patterns and CRT outcome. Cluster analysis algorithms were developed and optimized to maximize their ability to predict CRT response. Methods: About 49 patients (N = 27 ischemic etiology) received a SPECT RNA scan as well as positron emission tomography (PET) perfusion and viability scans prior to undergoing CRT. A semiautomated algorithm sampled the left ventricle wall to produce 568 TACs from SPECT RNA data. The TACs were then subjected to two different cluster analysis techniques, K-means, and normal average, where several input metrics were also varied to determine the optimal settings for the prediction of CRT outcome. Each TAC was assigned to a cluster group based on the comparison criteria and global and segmental cluster size and scores were used as measures of dyssynchrony and used to predict response to CRT. A repeated random twofold cross-validation technique was used to train and validate the cluster algorithm. Receiver operating characteristic (ROC) analysis was used to calculate the area under the curve (AUC) and compare results to those obtained for SPECT RNA phase analysis and PET scar size analysis methods. Results: Using the normal average cluster analysis approach, the septal wall produced statistically significant results for predicting CRT results in the ischemic population (ROC AUC = 0.73;p < 0.05 vs. equal chance ROC AUC = 0.50) with an optimal operating point of 71% sensitivity and 60% specificity. Cluster

  5. Design and assessment of cardiac SPECT systems

    NASA Astrophysics Data System (ADS)

    Lee, Chih-Jie

    Single-photon emission computed tomography (SPECT) is a modality widely used to detect myocardial ischemia and myocardial infarction. Objectively assessing and comparing different SPECT systems is important so that the best detectability of cardiac defects can be achieved. Whitaker, Clarkson, and Barrett's study on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than reconstruction data. Thus, this observer model assesses overall hardware performance independent by any reconstruction algorithm. In addition, we will show that the run time of image-quality studies is significantly reduced. Several systems derived from the GE CZT-based dedicated cardiac SPECT camera Discovery 530c design, which is officially named the Alcyone Technology: Discovery NM 530c, were assessed using the performance of the SLO for the task of detecting cardiac defects and estimating the properties of the defects. Clinically, hearts can be virtually segmented into three coronary artery territories: left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA). One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can correctly predict in which territory the defect exists. A good estimation of the defect extent from the images is also very helpful for determining the seriousness of the myocardial ischemia. In this dissertation, both locations and extent of defects were estimated by the SLO, and system performance was assessed using localization receiver operating characteristic (LROC) / estimation receiver operating characteristic (EROC) curves. Area under LROC curve (AULC) / area under EROC curve (AUEC) and true positive fraction (TPF) at specific false positive fraction (FPF) can be treated as the gures of merit (FOMs). As the results will show, a

  6. Regional cerebral blood flow imaging: A quantitative comparison of technetium-99m-HMPAO SPECT with C15O2 PET

    SciTech Connect

    Gemmell, H.G.; Evans, N.T.; Besson, J.A.; Roeda, D.; Davidson, J.; Dodd, M.G.; Sharp, P.F.; Smith, F.W.; Crawford, J.R.; Newton, R.H. )

    1990-10-01

    The aim of this study was to compare technetium-99m-hexamethylpropyleneamineoxime ({sup 99m}Tc-HMPAO) single-photon emission computed tomography (SPECT) with regional cerebral blood flow (rCBF) imaging using positron emission tomography (PET). As investigation of dementia is likely to be one of the main uses of routine rCBF imaging, 18 demented patients were imaged with both techniques. The PET data were compared quantitatively with three versions of the SPECT data. These were, first, data normalized to the SPECT cerebellar uptake, second, data linearly corrected using the PET cerebellar value and, finally, data Lassen corrected for washout from the high flow areas. Both the linearly-corrected (r = 0.81) and the Lassen-corrected (r = 0.79) HMPAO SPECT data showed good correlation with the PET rCBF data. The relationship between the normalized HMPAO SPECT data and the PET data was nonlinear. It is not yet possible to obtain rCBF values in absolute units from HMPAO SPECT without knowledge of the true rCBF in one reference region for each patient.

  7. Quantitative Monte Carlo-based holmium-166 SPECT reconstruction

    SciTech Connect

    Elschot, Mattijs; Smits, Maarten L. J.; Nijsen, Johannes F. W.; Lam, Marnix G. E. H.; Zonnenberg, Bernard A.; Bosch, Maurice A. A. J. van den; Jong, Hugo W. A. M. de; Viergever, Max A.

    2013-11-15

    Purpose: Quantitative imaging of the radionuclide distribution is of increasing interest for microsphere radioembolization (RE) of liver malignancies, to aid treatment planning and dosimetry. For this purpose, holmium-166 ({sup 166}Ho) microspheres have been developed, which can be visualized with a gamma camera. The objective of this work is to develop and evaluate a new reconstruction method for quantitative {sup 166}Ho SPECT, including Monte Carlo-based modeling of photon contributions from the full energy spectrum.Methods: A fast Monte Carlo (MC) simulator was developed for simulation of {sup 166}Ho projection images and incorporated in a statistical reconstruction algorithm (SPECT-fMC). Photon scatter and attenuation for all photons sampled from the full {sup 166}Ho energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy- and distance-dependent collimator-detector response was modeled using precalculated convolution kernels. Phantom experiments were performed to quantitatively evaluate image contrast, image noise, count errors, and activity recovery coefficients (ARCs) of SPECT-fMC in comparison with those of an energy window-based method for correction of down-scattered high-energy photons (SPECT-DSW) and a previously presented hybrid method that combines MC simulation of photopeak scatter with energy window-based estimation of down-scattered high-energy contributions (SPECT-ppMC+DSW). Additionally, the impact of SPECT-fMC on whole-body recovered activities (A{sup est}) and estimated radiation absorbed doses was evaluated using clinical SPECT data of six {sup 166}Ho RE patients.Results: At the same noise level, SPECT-fMC images showed substantially higher contrast than SPECT-DSW and SPECT-ppMC+DSW in spheres ≥17 mm in diameter. The count error was reduced from 29% (SPECT-DSW) and 25% (SPECT-ppMC+DSW) to 12% (SPECT-fMC). ARCs in five spherical volumes of 1.96–106.21 ml were improved from 32%–63% (SPECT-DSW) and 50%–80

  8. A small-animal imaging system capable of multipinhole circular/helical SPECT and parallel-hole SPECT

    PubMed Central

    Qian, Jianguo; Bradley, Eric L.; Majewski, Stan; Popov, Vladimir; Saha, Margaret S.; Smith, Mark F.; Weisenberger, Andrew G.; Welsh, Robert E.

    2008-01-01

    We have designed and built a small animal single photon emission computed tomography (SPECT) imaging system equipped with parallel-hole and multipinhole collimators and capable of circular or helical SPECT. Copper-beryllium parallel-hole collimators suitable for imaging the ~35 keV photons from the decay of 125I have been built and installed to achieve useful spatial resolution over a range of object-detector distances and to reduce imaging time on our dual-detector array. To address the resolution limitations in the parallel-hole SPECT and the sensitivity and limited field of view of single-pinhole SPECT, we have incorporated multipinhole circular and helical SPECT in addition to expanding the parallel-hole SPECT capabilities. The pinhole SPECT system is based on a 110 mm diameter circular detector equipped with a pixellated NaI(Tl) scintillator array (1×1×5 mm3/pixel). The helical trajectory is accomplished by two stepping motors controlling the rotation of the detector-support gantry and displacement of the animal bed along the axis of rotation of the gantry. Results obtained in SPECT studies of various phantoms show an enlarged field of view, very good resolution and improved sensitivity using multipinhole circular or helical SPECT. Collimators with one, three and five 1 mm diameter pinholes have been implemented and compared in these tests. Our objective is to develop a system on which one may readily select a suitable mode of either parallel-hole SPECT or pinhole circular or helical SPECT for a variety of small animal imaging applications. PMID:19701447

  9. A Depth-of-Interaction encoding method for SPECT monolithic scintillation detectors

    NASA Astrophysics Data System (ADS)

    Bettiol, M.; Preziosi, E.; Cinti, M. N.; Borrazzo, C.; Fabbri, A.; Cassano, B.; Polito, C.; Pellegrini, R.; Pani, R.

    2016-12-01

    The Depth of Interaction (DoI) discrimination of gamma-photons within scintillation crystals allows to improve imaging performance in PET scanners as well as in SPECT devices equipped with non-parallel collimators (e. g. pinhole ones). In previous works, the authors experimentally proved the efficiency of a DoI-encoding technique in case of a 20 mm-thick monolithic crystal PET module. For the thinner crystals commonly used in SPECT, DoI determination still remains a challenging goal. To this aim, in this work the authors have experimentally evaluated the DoI-encoding method on a 6 mm-thick monolithic LaBr3:Ce crystal. The results prove the efficiency and reliability of the proposed method. It indeed allows to discriminate the gamma photons interacting at the the top and the bottom of the crystal.

  10. GATE: a simulation toolkit for PET and SPECT.

    PubMed

    Jan, S; Santin, G; Strul, D; Staelens, S; Assié, K; Autret, D; Avner, S; Barbier, R; Bardiès, M; Bloomfield, P M; Brasse, D; Breton, V; Bruyndonckx, P; Buvat, I; Chatziioannou, A F; Choi, Y; Chung, Y H; Comtat, C; Donnarieix, D; Ferrer, L; Glick, S J; Groiselle, C J; Guez, D; Honore, P F; Kerhoas-Cavata, S; Kirov, A S; Kohli, V; Koole, M; Krieguer, M; van der Laan, D J; Lamare, F; Largeron, G; Lartizien, C; Lazaro, D; Maas, M C; Maigne, L; Mayet, F; Melot, F; Merheb, C; Pennacchio, E; Perez, J; Pietrzyk, U; Rannou, F R; Rey, M; Schaart, D R; Schmidtlein, C R; Simon, L; Song, T Y; Vieira, J M; Visvikis, D; Van de Walle, R; Wieërs, E; Morel, C

    2004-10-07

    Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at http:/www-lphe.epfl.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects towards the gridification of GATE and its extension to other domains such as dosimetry are also discussed.

  11. Patient doses from hybrid SPECT-CT procedures.

    PubMed

    Avramova-Cholakova, S; Dimcheva, M; Petrova, E; Garcheva, M; Dimitrova, M; Palashev, Y; Vassileva, J

    2015-07-01

    The aim of this work is to estimate patient doses from hybrid single-photon emission computed tomography (SPECT) and computed tomography (CT) procedures. The study involved all four SPECT-CT systems in Bulgaria. Effective dose was estimated for about 100 patients per system. Ten types of examinations were considered, representing all diagnostic procedures performed in the SPECT-CT systems. Effective doses from the SPECT component were calculated applying the ICRP 53 and ICRP 80 conversion coefficients. Computed tomography dose index and dose length product were retrospectively obtained from the archives of the systems, and effective doses from the CT component were calculated with CT-Expo software. Parallel estimation of CT component contribution with the National Radiological Protection Board (NRPB) conversion coefficients was performed where applicable. Large variations were found in the current practice of SPECT-CT imaging. Optimisation actions and diagnostic reference levels were proposed.

  12. Noninvasive Assessment of Myocardial Viability in a Small Animal Model: Comparison of MRI, SPECT, and PET

    PubMed Central

    Thomas, Daniel; Bal, Harshali; Arkles, Jeffrey; Horowitz, James; Araujo, Luis; Acton, Paul D.; Ferrari, Victor A.

    2010-01-01

    Acute myocardial infarction (AMI) research relies increasingly on small animal models and noninvasive imaging methods such as MRI, single-photon emission computed tomography (SPECT), and positron emission tomography (PET). However, a direct comparison among these techniques for characterization of perfusion, viability, and infarct size is lacking. Rats were studied within 18–24 hr post AMI by MRI (4.7 T) and subsequently (40–48 hr post AMI) by SPECT (99Tc-MIBI) and micro-PET (18FDG). A necrosis-specific MRI contrast agent was used to detect AMI, and a fast low angle shot (FLASH) sequence was used to acquire late enhancement and functional images contemporaneously. Infarcted regions showed late enhancement, whereas corresponding radionuclide images had reduced tracer uptake. MRI most accurately depicted AMI, showing the closest correlation and agreement with triphenyl tetrazolium chloride (TTC), followed by SPECT and PET. In some animals a mismatch of reduced uptake in normal myocardium and relatively increased 18FDG uptake in the infarct border zone precluded conventional quantitative analysis. We performed the first quantitative comparison of MRI, PET, and SPECT for reperfused AMI imaging in a small animal model. MRI was superior to the other modalities, due to its greater spatial resolution and ability to detect necrotic myocardium directly. The observed 18FDG mismatch likely represents variable metabolic conditions between stunned myocardium in the infarct border zone and normal myocardium and supports the use of a standardized glucose load or glucose clamp technique for PET imaging of reperfused AMI in small animals. PMID:18228591

  13. 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.

  14. 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.

  15. (99m)Tc-labelled nanosystem as tumour imaging agent for SPECT and SPECT/CT modalities.

    PubMed

    Polyák, András; Hajdu, István; Bodnár, Magdolna; Trencsényi, György; Pöstényi, Zita; Haász, Veronika; Jánoki, Gergely; Jánoki, Győző A; Balogh, Lajos; Borbély, János

    2013-06-05

    We report the synthesis, in vitro and in vivo investigation of folate-targeted, biocompatible, biodegradable self-assembled nanoparticles radiolabelled with (99m)Tc, as potential new SPECT or SPECT/CT imaging agent. Nanoparticles with hydrodynamic size in the range of 75-200 nm were prepared by self-assembly of chitosan and folated poly-γ-glutamic acid, and then radiolabelled with (99m)Tc. The nanoparticles target tumour cells overexpressing folate receptors and internalize specifically into them to realize early tumour diagnosis detected by SPECT and SPECT/CT modalities. Rat hepatocellular carcinoma cells were used as model system. Cell specificity and tumour targeting efficacy of these nanosystems were investigated in vitro, and in vivo using SPECT and fusion nanoSPECT/CT imaging. In vitro results showed that the radiolabeled nanosystem was efficiently internalized by tumour cells. Whole-body biodistribution of the new radiolabelled, folate-targeted nanoparticles revealed higher uptake in the tumorous kidney compared to the non-tumorous contralateral side. Uptake by the lungs and thyroids was negligible, which confirmed the stability of the nanoparticles in vivo. In vivo SPECT and SPECT/CT imaging visually reinforced the uptake results and were in accordance with the biodistribution data: the new nanoparticles as a targeted contrast agent improve tumour targeting and are able to detect folate-receptor-overexpressing tumours in animal models with enhanced contrast.

  16. Analysis of SPECT brain images for the diagnosis of Alzheimer's disease based on NMF for feature extraction.

    PubMed

    Padilla, P; Górriz, J M; Ramírez, J; Lang, E W; Chaves, R; Segovia, F; López, M; Salas-González, D; Alvarez, I

    2010-08-02

    This letter presents a novel computer-aided diagnosis (CAD) technique for the early diagnosis of Alzheimer's disease (AD) based on non-negative matrix factorization (NMF) analysis applied to single photon emission computed tomography (SPECT) images. A baseline normalized SPECT database containing normalized data for both AD patients and healthy reference patients is selected for this study. The SPECT database is analyzed by applying the Fisher discriminant ratio (FDR) for feature selection and NMF for feature extraction of relevant components of each subject. The main goal of these preprocessing steps is to reduce the large dimensionality of the input data and to relieve the so called "curse of dimensionality" problem. The resulting NMF-transformed set of data, which contains a reduced number of features, is classified by means of a support vector machines based classification technique (SVM). The proposed NMF + SVM method yields up to 94% classification accuracy, with high sensitivity and specificity values (upper than 90%), becoming an accurate method for SPECT image classification. For the sake of completeness, comparison between another recently developed principal component analysis (PCA) plus SVM method and the proposed method is also provided, yielding results for the NMF + SVM approach that outperform the behavior of the reference PCA + SVM or conventional voxel-as-feature (VAF) plus SVM methods.

  17. 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

  18. Bayesian learning for cardiac SPECT image interpretation.

    PubMed

    Sacha, Jarosław P; Goodenday, Lucy S; Cios, Krzysztof J

    2002-01-01

    In this paper, we describe a system for automating the diagnosis of myocardial perfusion from single-photon emission computerized tomography (SPECT) images of male and female hearts. Initially we had several thousand of SPECT images, other clinical data and physician-interpreter's descriptions of the images. The images were divided into segments based on the Yale system. Each segment was described by the physician as showing one of the following conditions: normal perfusion, reversible perfusion defect, partially reversible perfusion defect, fixed perfusion defect, defect showing reverse redistribution, equivocal defect or artifact. The physician's diagnosis of overall left ventricular (LV) perfusion, based on the above descriptions, categorizes a study as showing one or more of eight possible conditions: normal, ischemia, infarct and ischemia, infarct, reverse redistribution, equivocal, artifact or LV dysfunction. Because of the complexity of the task, we decided to use the knowledge discovery approach, consisting of these steps: problem understanding, data understanding, data preparation, data mining, evaluating the discovered knowledge and its implementation. After going through the data preparation step, in which we constructed normal gender-specific models of the LV and image registration, we ended up with 728 patients for whom we had both SPECT images and corresponding diagnoses. Another major contribution of the paper is the data mining step, in which we used several new Bayesian learning classification methods. The approach we have taken, namely the six-step knowledge discovery process has proven to be very successful in this complex data mining task and as such the process can be extended to other medical data mining projects.

  19. 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

  20. System calibration and image reconstruction for a new small-animal SPECT system

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Chun

    A novel small-animal SPECT imager, FastSPECT II, was recently developed at the Center for Gamma-Ray Imaging. FastSPECT II consists of two rings of eight modular scintillation cameras and list-mode data-acquisition electronics that enable stationary and dynamic imaging studies. The instrument is equipped with exchangeable aperture assemblies and adjustable camera positions for selections of magnifications, pinhole sizes, and fields of view (FOVs). The purpose of SPECT imaging is to recover the radiotracer distribution in the object from the measured image data. Accurate knowledge of the imaging system matrix (referred to as H) is essential for image reconstruction. To assure that all of the system physics is contained in the matrix, experimental calibration methods for the individual cameras and the whole imaging system were developed and carefully performed. The average spatial resolution over the FOV of FastSPECT II in its low-magnification (2.4X) configuration is around 2.4 mm, computed from the Fourier crosstalk matrix. The system sensitivity measured with a 99mTc point source at the center of the FOV is about 267 cps/MBq. The system detectability was evaluated by computing the ideal-observer performance on SKE/BKE (signal-known-exactly/background-known-exactly) detection tasks. To reduce the system-calibration time and achieve finer reconstruction grids, two schemes for interpolating H were implemented and compared: these are centroid interpolation with Gaussian fitting and Fourier interpolation. Reconstructed phantom and mouse-cardiac images demonstrated the effectiveness of the H-matrix interpolation. Tomographic reconstruction can be formulated as a linear inverse problem and solved using statistical-estimation techniques. Several iterative reconstruction algorithms were introduced, including maximum-likelihood expectation-maximization (ML-EM) and its ordered-subsets (OS) version, and some least-squares (LS) and weighted-least-squares (WLS) algorithms such

  1. PET/SPECT molecular imaging in clinical neuroscience: recent advances in the investigation of CNS diseases

    PubMed Central

    Lu, Feng-Mei

    2015-01-01

    Molecular imaging is an attractive technology widely used in clinical practice that greatly enhances our understanding of the pathophysiology and treatment in central nervous system (CNS) diseases. It is a novel multidisciplinary technique that can be defined as real-time visualization, in vivo characterization and qualification of biological processes at the molecular and cellular level. It involves the imaging modalities and the corresponding imaging agents. Nowadays, molecular imaging in neuroscience has provided tremendous insights into disturbed human brain function. Among all of the molecular imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT) have occupied a particular position that visualize and measure the physiological processes using high-affinity and high-specificity molecular radioactive tracers as imaging probes in intact living brain. In this review, we will put emphasis on the PET/SPECT applications in Alzheimer’s disease (AD) and Parkinson’s disease (PD) as major CNS disorders. We will first give an overview of the main classical molecular neuroimaging modalities. Then, the major clinical applications of PET and SPECT along with molecular probes in the fields of psychiatry and neurology will be discussed. PMID:26029646

  2. Ictal/postictal SPECT in the pre-surgical localisation of complex partial seizures.

    PubMed

    Duncan, R; Patterson, J; Roberts, R; Hadley, D M; Bone, I

    1993-02-01

    Single photon emission computed tomography (SPECT) used in conjunction with HM-PAO (Ceretec-Amersham International) was used to image regional cerebral blood flow (rCBF) in 28 patients with medically intractable complex partial seizures during or soon after a seizure, and interictally. Changes from interictal rCBF were seen in 26/28 (93%) patients. The main findings were; 1) During the seizure--hyperperfusion of the whole temporal lobe; 2) Up to 2m postically--hyperperfusion of the hippocampus with hypoperfusion of lateral temporal structures; 3) From 2-15m postically--hypoperfusion of the whole temporal lobe. When compared with EEG and MRI data, correct localisation to one temporal lobe was obtained in 23 patients. In one further patient bilateral temporal foci, and in a further two patients frontal foci, were correctly identified. There were no disagreements between EEG and SPECT localisation. Temporal lobe surgery was successful (by the criterion of at least 90% reduction in seizure frequency) in all but one of the 23 patients operated on. It is concluded that ictal/postictal SPECT is a reliable technique for the presurgical localisation of complex partial seizures. The data indicate a likely sequence of changes in rCBF during and after complex partial seizures of temporal lobe origin.

  3. Functional brain abnormalities localized in 55 chronic tinnitus patients: fusion of SPECT coincidence imaging and MRI.

    PubMed

    Farhadi, Mohammad; Mahmoudian, Saeid; Saddadi, Fariba; Karimian, Ali Reza; Mirzaee, Mohammad; Ahmadizadeh, Majid; Ghasemikian, Khosro; Gholami, Saeid; Ghoreyshi, Esmaeel; Beyty, Saeid; Shamshiri, Ahmadreza; Madani, Sedighe; Bakaev, Valery; Moradkhani, Seddighe; Raeisali, Gholamreza

    2010-04-01

    Tinnitus is often defined as the perception of sounds or noise in the absence of any external auditory stimuli. The pathophysiology of subjective idiopathic tinnitus remains unclear. The aim of this study was to investigate the functional brain activities and possible involved cerebral areas in subjective idiopathic tinnitus patients by means of single photon emission computerized tomography (SPECT) coincidence imaging, which was fused with magnetic resonance imaging (MRI). In this cross-sectional study, 56 patients (1 subject excluded) with subjective tinnitus and 8 healthy controls were enrolled. After intravenous injection of 5 mCi F18-FDG (fluorodeoxyglucose), all subjects underwent a brain SPECT coincidence scan, which was then superimposed on their MRIs. In the eight regions of interest (middle temporal, inferotemporal, medial temporal, lateral temporal, temporoparietal, frontal, frontoparietal, and parietal areas), the more pronounced values were represented in medial temporal, inferotemporal, and temporoparietal areas, which showed more important proportion of associative auditory cortices in functional attributions of tinnitus than primary auditory cortex. Brain coincidence SPECT scan, when fused on MRI is a valuable technique in the assessment of patients with tinnitus and could show the significant role of different regions of central nervous system in functional attributions of tinnitus.

  4. Functional brain abnormalities localized in 55 chronic tinnitus patients: fusion of SPECT coincidence imaging and MRI

    PubMed Central

    Farhadi, Mohammad; Mahmoudian, Saeid; Saddadi, Fariba; Karimian, Ali Reza; Mirzaee, Mohammad; Ahmadizadeh, Majid; Ghasemikian, Khosro; Gholami, Saeid; Ghoreyshi, Esmaeel; Beyty, Saeid; Shamshiri, Ahmadreza; Madani, Sedighe; Bakaev, Valery; Moradkhani, Seddighe; Raeisali, Gholamreza

    2010-01-01

    Tinnitus is often defined as the perception of sounds or noise in the absence of any external auditory stimuli. The pathophysiology of subjective idiopathic tinnitus remains unclear. The aim of this study was to investigate the functional brain activities and possible involved cerebral areas in subjective idiopathic tinnitus patients by means of single photon emission computerized tomography (SPECT) coincidence imaging, which was fused with magnetic resonance imaging (MRI). In this cross-sectional study, 56 patients (1 subject excluded) with subjective tinnitus and 8 healthy controls were enrolled. After intravenous injection of 5 mCi F18-FDG (fluorodeoxyglucose), all subjects underwent a brain SPECT coincidence scan, which was then superimposed on their MRIs. In the eight regions of interest (middle temporal, inferotemporal, medial temporal, lateral temporal, temporoparietal, frontal, frontoparietal, and parietal areas), the more pronounced values were represented in medial temporal, inferotemporal, and temporoparietal areas, which showed more important proportion of associative auditory cortices in functional attributions of tinnitus than primary auditory cortex. Brain coincidence SPECT scan, when fused on MRI is a valuable technique in the assessment of patients with tinnitus and could show the significant role of different regions of central nervous system in functional attributions of tinnitus. PMID:20068582

  5. Organ-specific SPECT activity calibration using 3D printed phantoms for molecular radiotherapy dosimetry.

    PubMed

    Robinson, Andrew P; Tipping, Jill; Cullen, David M; Hamilton, David; Brown, Richard; Flynn, Alex; Oldfield, Christopher; Page, Emma; Price, Emlyn; Smith, Andrew; Snee, Richard

    2016-12-01

    Patient-specific absorbed dose calculations for molecular radiotherapy require accurate activity quantification. This is commonly derived from Single-Photon Emission Computed Tomography (SPECT) imaging using a calibration factor relating detected counts to known activity in a phantom insert. A series of phantom inserts, based on the mathematical models underlying many clinical dosimetry calculations, have been produced using 3D printing techniques. SPECT/CT data for the phantom inserts has been used to calculate new organ-specific calibration factors for (99m) Tc and (177)Lu. The measured calibration factors are compared to predicted values from calculations using a Gaussian kernel. Measured SPECT calibration factors for 3D printed organs display a clear dependence on organ shape for (99m) Tc and (177)Lu. The observed variation in calibration factor is reproduced using Gaussian kernel-based calculation over two orders of magnitude change in insert volume for (99m) Tc and (177)Lu. These new organ-specific calibration factors show a 24, 11 and 8 % reduction in absorbed dose for the liver, spleen and kidneys, respectively. Non-spherical calibration factors from 3D printed phantom inserts can significantly improve the accuracy of whole organ activity quantification for molecular radiotherapy, providing a crucial step towards individualised activity quantification and patient-specific dosimetry. 3D printed inserts are found to provide a cost effective and efficient way for clinical centres to access more realistic phantom data.

  6. Multi-resolution multi-sensitivity design for parallel-hole SPECT collimators.

    PubMed

    Li, Yanzhao; Xiao, Peng; Zhu, Xiaohua; Xie, Qingguo

    2016-07-21

    Multi-resolution multi-sensitivity (MRMS) collimator offering adjustable trade-off between resolution and sensitivity, can make a SPECT system adaptive. We propose in this paper a new idea for MRMS design based on, for the first time, parallel-hole collimators for clinical SPECT. Multiple collimation states with varied resolution/sensitivity trade-offs can be formed by slightly changing the collimator's inner structure. To validate the idea, the GE LEHR collimator is selected as the design prototype and is modeled using a ray-tracing technique. Point images are generated for several states of the design. Results show that the collimation states of the design can obtain similar point response characteristics to parallel-hole collimators, and can be used just like parallel-hole collimators in clinical SPECT imaging. Ray-tracing modeling also shows that the proposed design can offer varied resolution/sensitivity trade-offs: at 100 mm before the collimator, the highest resolution state provides 6.9 mm full width at a half maximum (FWHM) with a nearly minimum sensitivity of about 96.2 cps MBq(-1), while the lowest resolution state obtains 10.6 mm FWHM with the highest sensitivity of about 167.6 cps MBq(-1). Further comparisons of the states on image qualities are conducted through Monte Carlo simulation of a hot-spot phantom which contains five hot spots with varied sizes. Contrast-to-noise ratios (CNR) of the spots are calculated and compared, showing that different spots can prefer different collimation states: the larger spots obtain better CNRs by using the larger sensitivity states, and the smaller spots prefer the higher resolution states. In conclusion, the proposed idea can be an effective approach for MRMS design for parallel-hole SPECT collimators.

  7. Brain SPECT guided repetitive transcranial magnetic stimulation (rTMS) in treatment resistant major depressive disorder.

    PubMed

    Jha, Shailesh; Chadda, Rakesh K; Kumar, Nand; Bal, C S

    2016-06-01

    Repetitive transcranial magnetic stimulation (rTMS) has emerged as a potential treatment in treatment resistant major depressive disorder (MDD). However, there is no consensus about the exact site of stimulation for rTMS. Single-photon emission computed tomography (SPECT) offers a potential technique in deciding the site of stimulation. The present study was conducted to assess the difference in outcome of brain SPECT assisted rTMS versus standard protocol of twenty sessions of high frequency rTMS as add on treatment in 20 patients with treatment resistant MDD, given over a period of 4 weeks. Thirteen subjects (group I) received high frequency rTMS over an area of hypoperfusion in the prefrontal cortex, as identified on SPECT, whereas 7 subjects (group II) were administered rTMS in the left dorsoslateral prefrontal cortex (DLPFC) area. Improvement was monitored using standardized instruments. Patients in the group I showed a significantly better response compared to those in the group II. In group I, 46% of the subjects were responders on MADRS, 38% on BDI and 77% on CGI. The parallel figures of responders in Group II were 0% on MADRS, 14% on BDI and 43% on CGI. There were no remitters in the study. No significant untoward side effects were noticed. The study had limitations of a small sample size and non-controlled design, and all the subjects were also receiving the standard antidepressant therapy. Administration of rTMS over brain SPECT specified area of hypoperfusion may have a better clinical outcome compared to the standard protocol.

  8. Multi-resolution multi-sensitivity design for parallel-hole SPECT collimators

    NASA Astrophysics Data System (ADS)

    Li, Yanzhao; Xiao, Peng; Zhu, Xiaohua; Xie, Qingguo

    2016-07-01

    Multi-resolution multi-sensitivity (MRMS) collimator offering adjustable trade-off between resolution and sensitivity, can make a SPECT system adaptive. We propose in this paper a new idea for MRMS design based on, for the first time, parallel-hole collimators for clinical SPECT. Multiple collimation states with varied resolution/sensitivity trade-offs can be formed by slightly changing the collimator’s inner structure. To validate the idea, the GE LEHR collimator is selected as the design prototype and is modeled using a ray-tracing technique. Point images are generated for several states of the design. Results show that the collimation states of the design can obtain similar point response characteristics to parallel-hole collimators, and can be used just like parallel-hole collimators in clinical SPECT imaging. Ray-tracing modeling also shows that the proposed design can offer varied resolution/sensitivity trade-offs: at 100 mm before the collimator, the highest resolution state provides 6.9 mm full width at a half maximum (FWHM) with a nearly minimum sensitivity of about 96.2 cps MBq-1, while the lowest resolution state obtains 10.6 mm FWHM with the highest sensitivity of about 167.6 cps MBq-1. Further comparisons of the states on image qualities are conducted through Monte Carlo simulation of a hot-spot phantom which contains five hot spots with varied sizes. Contrast-to-noise ratios (CNR) of the spots are calculated and compared, showing that different spots can prefer different collimation states: the larger spots obtain better CNRs by using the larger sensitivity states, and the smaller spots prefer the higher resolution states. In conclusion, the proposed idea can be an effective approach for MRMS design for parallel-hole SPECT collimators.

  9. Role of auditory brain function assessment by SPECT in cochlear implant side selection.

    PubMed

    Di Nardo, W; Giannantonio, S; Di Giuda, D; De Corso, E; Schinaia, L; Paludetti, G

    2013-02-01

    Pre-surgery evaluation, indications for cochlear implantation and expectations in terms of post-operative functional results remain challenging topics in pre-lingually deaf adults. Our study has the purpose of determining the benefits of Single Photon Emission Tomography (SPECT) assessment in pre-surgical evaluation of pre-lingually deaf adults who are candidates for cochlear implantation. In 7 pre-lingually profoundly deaf patients, brain SPECT was performed at baseline conditions and in bilateral simultaneous multi-frequency acoustic stimulation. Six sagittal tomograms of both temporal cortices were used for semi-quantitative analysis in each patient. Percentage increases in cortical perfusion resulting from auditory stimulation were calculated. The results showed an inter-hemispherical asymmetry of the activation extension and intensity in the stimulated temporal areas. Consistent with the obtained brain activation data, patients were implanted preferring the side that showed higher activation after acoustic stimulus. Considering the increment in auditory perception performances, it was possible to point out a relationship between cortical brain activity shown by SPECT and hearing performances, and, even more significant, a correlation between post-operative functional performances and the activation of the most medial part of the sagittal temporal tomograms, corresponding to medium-high frequencies. In light of these findings, we believe that brain SPECT could be considered in the evaluation of deaf patients candidate for cochlear implantation, and that it plays a major role in functional assessment of the auditory cortex of pre-lingually deaf subjects, even if further studies are necessary to conclusively establish its utility. Further developments of this technique are possible by using trans-tympanic electrical stimulation of the cochlear promontory, which could give the opportunity to study completely deaf patients, whose evaluation is objectively difficult

  10. Myocardial Infarction Area Quantification using High-Resolution SPECT Images in Rats

    PubMed Central

    de Oliveira, Luciano Fonseca Lemos; Mejia, Jorge; de Carvalho, Eduardo Elias Vieira; Lataro, Renata Maria; Frassetto, Sarita Nasbine; Fazan, Rubens; Salgado, Hélio Cesar; Galvis-Alonso, Orfa Yineth; Simões, Marcus Vinícius

    2013-01-01

    Background Imaging techniques enable in vivo sequential assessment of the morphology and function of animal organs in experimental models. We developed a device for high-resolution single photon emission computed tomography (SPECT) imaging based on an adapted pinhole collimator. Objective To determine the accuracy of this system for quantification of myocardial infarct area in rats. Methods Thirteen male Wistar rats (250 g) underwent experimental myocardial infarction by occlusion of the left coronary artery. After 4 weeks, SPECT images were acquired 1.5 hours after intravenous injection of 555 MBq of 99mTc-Sestamibi. The tomographic reconstruction was performed by using specially developed software based on the Maximum Likelihood algorithm. The analysis of the data included the correlation between the area of perfusion defects detected by scintigraphy and extent of myocardial fibrosis assessed by histology. Results The images showed a high target organ/background ratio with adequate visualization of the left ventricular walls and cavity. All animals presenting infarction areas were correctly identified by the perfusion images. There was no difference of the infarct area as measured by SPECT (21.1 ± 21.2%) and by histology (21.7 ± 22.0%; p=0.45). There was a strong correlation between individual values of the area of infarction measured by these two methods. Conclusion The developed system presented adequate spatial resolution and high accuracy for the detection and quantification of myocardial infarction areas, consisting in a low cost and versatile option for high-resolution SPECT imaging of small rodents. PMID:23917507

  11. PET and SPECT studies in Parkinson's disease.

    PubMed

    Brooks, D J

    1997-04-01

    Positron emission tomography (PET) and single photon emission tomography (SPECT) provide sensitive means for quantifying the loss of nigrostriatal dopaminergic fibres in Parkinson's disease and for detecting the presence of dopaminergic dysfunction in asymptomatic at-risk relatives and patients with isolated tremor. Functional imaging can also be used to follow the rate of disease progression objectively, determine the efficacy of putative neuroprotective agents, and monitor the viability of transplants of fetal tissue. Additionally, in vivo pharmacological changes associated with development of treatment complications (fluctuations, dyskinesias) can be studied. Loss of dopaminergic projections produces profound changes in resting and activated brain metabolism. PET and SPECT activation studies have suggested that the akinesia of Parkinson's disease is associated with failure to activate the supplementary motor and dorsal pre-frontal areas. Activation of these cortical areas is restored towards normal by the use of dopaminergic medication, striatal transplantation with fetal mesencephalic tissue, and pallidotomy. The aim of this chapter is to review the insight which functional imaging has given us into the pathophysiology of parkinsonism.

  12. MLEM algorithm adaptation for improved SPECT scintimammography

    NASA Astrophysics Data System (ADS)

    Krol, Andrzej; Feiglin, David H.; Lee, Wei; Kunniyur, Vikram R.; Gangal, Kedar R.; Coman, Ioana L.; Lipson, Edward D.; Karczewski, Deborah A.; Thomas, F. Deaver

    2005-04-01

    Standard MLEM and OSEM algorithms used in SPECT Tc-99m sestamibi scintimammography produce hot-spot artifacts (HSA) at the image support peripheries. We investigated a suitable adaptation of MLEM and OSEM algorithms needed to reduce HSA. Patients with suspicious breast lesions were administered 10 mCi of Tc-99m sestamibi and SPECT scans were acquired for patients in prone position with uncompressed breasts. In addition, to simulate breast lesions, some patients were imaged with a number of breast skin markers each containing 1 mCi of Tc-99m. In order to reduce HSA in reconstruction, we removed from the backprojection step the rays that traverse the periphery of the support region on the way to a detector bin, when their path length through this region was shorter than some critical length. Such very short paths result in a very low projection counts contributed to the detector bin, and consequently to overestimation of the activity in the peripheral voxels in the backprojection step-thus creating HSA. We analyzed the breast-lesion contrast and suppression of HSA in the images reconstructed using standard and modified MLEM and OSEM algorithms vs. critical path length (CPL). For CPL >= 0.01 pixel size, we observed improved breast-lesion contrast and lower noise in the reconstructed images, and a very significant reduction of HSA in the maximum intensity projection (MIP) images.

  13. Quantitative SPECT of uptake of monoclonal antibodies

    SciTech Connect

    DeNardo, G.L.; Macey, D.J.; DeNardo, S.J.; Zhang, C.G.; Custer, T.R.

    1989-01-01

    Absolute quantitation of the distribution of radiolabeled antibodies is important to the efficient conduct of research with these agents and their ultimate use for imaging and treatment, but is formidable because of the unrestricted nature of their distribution within the patient. Planar imaging methods have been developed and provide an adequate approximation of the distribution of radionuclide for many purposes, particularly when there is considerable specificity of targeting. This is not currently the case for antibodies and is unlikely in the future. Single photon emission computed tomography (SPECT) provides potential for greater accuracy because it reduces problems caused by superimposition of tissues and non-target contributions to target counts. SPECT measurement of radionuclide content requires: (1) accurate determination of camera sensitivity; (2) accurate determination of the number of counts in a defined region of interest; (3) correction for attenuation; (4) correction for scatter and septal penetration; (5) accurate measurement of the administered dose; (6) adequate statistics; and (7) accurate definition of tissue mass or volume. The major impediment to each of these requirements is scatter of many types. The magnitude of this problem can be diminished by improvements in tomographic camera design, computer algorithms, and methodological approaches. 34 references.

  14. SPECT-US image fusion and clinical applications

    NASA Astrophysics Data System (ADS)

    Hummel, Johann; Kaar, Marcus; Hoffmann, Rainer; Birkfellner, Wolfgang; Beyer, Thomas; Staudenherz, Anton; Figl, Michael

    2014-03-01

    Because scintigraphic images lack anatomical information, single photon emission tomography (SPECT) and positron emission tomography systems (PET) are combined physically with CTs to compensate for this drawback. In our work, we present a method where the CT is replaced by a 3D ultrasound device. Because in this case a mechanical linkage is not possible, we use an additional optical tracking system (OTS) for spatial correlation of the SPECT or PET information and the US. To enable image fusion between the functional SPECT and the anatomical US we first calibrate the SPECT by means of the optical tracking system. This is done by imaging a phantom with SPECT and scanning the surface of the phantom using a calibrated stylus of the OTS. Applying an iterative closest point (ICP) algorithm results in the transformation between the optical coordinate system and the SPECT coordinate system. When a patient undergoes a SPECT scan, a 3D US image is taken immediately after the scan. Since the scan head of the US is also tracked by the OTS, the transformation between OTS and SPECT can be calculated straight forward. For clinical intervention, the patient is again imaged with the US and a 3D/3D registration between the two US volumes allows to transform the functional information of the SPECT to the current US image in real time. We found a mean distance between the point cloud of the optical stylus and the segmented surface of the phantom of 2.3 mm while the maximum distance was found to be 6.9 mm. The 3D3D registration between the two US images was accomplished with an error of 2.1 mm.

  15. 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

  16. Fractured osteophyte demonstrated on SPECT and computed tomography.

    PubMed

    Spieth, Michael E; Schmitz, Stacey L

    2003-08-01

    ABSTRACT We present an interesting case of a fractured osteophyte causing back pain that was demonstrated both on bone single photon emission computed tomography (SPECT) and computed tomography (CT). The magnetic resonance images, thoracic anterior spine plain radiograph, whole-body bone scan passes, and thoracic spot view were not impressive. Bone SPECT was the impetus for getting the CT scan. The CT scan not only demonstrated the osteophyte but a pseudarthrosis that was probably causing the pain. If it were not for the positive SPECT bone scan, the CT scan would not have been ordered after unimpressive magnetic resonance imaging.

  17. Parametric quantification of myocardial ischaemia using real-time perfusion adenosine stress echocardiography images, with SPECT as reference method.

    PubMed

    Gudmundsson, P; Shahgaldi, K; Winter, R; Dencker, M; Kitlinski, M; Thorsson, O; Ljunggren, L; Willenheimer, R

    2010-01-01

    Real-time perfusion (RTP) adenosine stress echocardiography (ASE) can be used to visually evaluate myocardial ischaemia. The RTP power modulation technique, provides images for off-line parametric perfusion quantification using Qontrast software. From replenishment curves, this generates parametric images of peak signal intensity (A), myocardial blood flow velocity (beta) and myocardial blood flow (Axbeta) at rest and stress. This may be a tool for objective myocardial ischaemia evaluation. We assessed myocardial ischaemia by RTP-ASE Qontrast((R))-generated images, using 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) as reference. Sixty-seven patients admitted to SPECT underwent RTP-ASE (SONOS 5500) during Sonovue infusion, before and throughout adenosine stress, also used for SPECT. Quantitative off-line analyses of myocardial perfusion by RTP-ASE Qontrast-generated A, beta and Axbeta images, at different time points during rest and stress, were blindly compared to SPECT. We analysed 201 coronary territories [corresponding to the left anterior descendent (LAD), left circumflex (LCx) and right coronary (RCA) arteries] from 67 patients. SPECT showed ischaemia in 18 patients. Receiver operator characteristics and kappa values showed that A, beta and Axbeta image interpretation significantly identified ischaemia in all territories (area under the curve 0.66-0.80, P = 0.001-0.05). Combined A, beta and Axbeta image interpretation gave the best results and the closest agreement was seen in the LAD territory: 89% accuracy; kappa 0.63; P<0.001. Myocardial isachemia can be evaluated in the LAD territory using RTP-ASE Qontrast-generated images, especially by combined A, beta and Axbeta image interpretation. However, the technique needs improvements regarding the LCx and RCA territories.

  18. 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.

  19. 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.

  20. Incremental value of (99m)Tc-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.

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

    SciTech Connect

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

    2013-12-15

    the Radon transform, estimation accuracy was reduced. The estimation error was associated with rounding errors of Radon transform, finite line-source width, Poisson noise, number of line sources, intrinsic camera resolution, and detector acquisition geometry. Statistically, the estimation accuracy was significantly improved by using four line sources rather than three and by thinner line-source projections (obtained by better intrinsic detector resolution). With five line sources, median errors were 0.2 mm for the detector translations, 0.7 mm for the detector radius of rotation, and less than 0.5° for detector rotation, tilt, and twist. In experimental evaluations, average errors relative to a different, independent registration technique were about 1.8 mm for detector translations, 1.1 mm for the detector radius of rotation (ROR), 0.5° and 0.4° for detector rotation and tilt, respectively, and 1.2° for detector twist.Conclusions: Alignment parameters can be estimated using one pinhole projection of line sources. Alignment errors are largely associated with limited accuracy of the Radon transform in determining angles (α) and offsets (ρ) of the line-source projections. This alignment method may be important for multipinhole SPECT, where relative pinhole alignment may vary during rotation. For pinhole and multipinhole SPECT imaging on-board radiation therapy machines, the method could provide alignment of SPECT coordinates with those of CBCT and the LINAC.

  2. Image reconstruction of single photon emission computed tomography (SPECT) on a pebble bed reactor (PBR) using expectation maximization and exact inversion algorithms: Comparison study by means of numerical phantom

    SciTech Connect

    Razali, Azhani Mohd Abdullah, Jaafar

    2015-04-29

    Single Photon Emission Computed Tomography (SPECT) is a well-known imaging technique used in medical application, and it is part of medical imaging modalities that made the diagnosis and treatment of disease possible. However, SPECT technique is not only limited to the medical sector. Many works are carried out to adapt the same concept by using high-energy photon emission to diagnose process malfunctions in critical industrial systems such as in chemical reaction engineering research laboratories, as well as in oil and gas, petrochemical and petrochemical refining industries. Motivated by vast applications of SPECT technique, this work attempts to study the application of SPECT on a Pebble Bed Reactor (PBR) using numerical phantom of pebbles inside the PBR core. From the cross-sectional images obtained from SPECT, the behavior of pebbles inside the core can be analyzed for further improvement of the PBR design. As the quality of the reconstructed image is largely dependent on the algorithm used, this work aims to compare two image reconstruction algorithms for SPECT, namely the Expectation Maximization Algorithm and the Exact Inversion Formula. The results obtained from the Exact Inversion Formula showed better image contrast and sharpness, and shorter computational time compared to the Expectation Maximization Algorithm.

  3. Image reconstruction of single photon emission computed tomography (SPECT) on a pebble bed reactor (PBR) using expectation maximization and exact inversion algorithms: Comparison study by means of numerical phantom

    NASA Astrophysics Data System (ADS)

    Razali, Azhani Mohd; Abdullah, Jaafar

    2015-04-01

    Single Photon Emission Computed Tomography (SPECT) is a well-known imaging technique used in medical application, and it is part of medical imaging modalities that made the diagnosis and treatment of disease possible. However, SPECT technique is not only limited to the medical sector. Many works are carried out to adapt the same concept by using high-energy photon emission to diagnose process malfunctions in critical industrial systems such as in chemical reaction engineering research laboratories, as well as in oil and gas, petrochemical and petrochemical refining industries. Motivated by vast applications of SPECT technique, this work attempts to study the application of SPECT on a Pebble Bed Reactor (PBR) using numerical phantom of pebbles inside the PBR core. From the cross-sectional images obtained from SPECT, the behavior of pebbles inside the core can be analyzed for further improvement of the PBR design. As the quality of the reconstructed image is largely dependent on the algorithm used, this work aims to compare two image reconstruction algorithms for SPECT, namely the Expectation Maximization Algorithm and the Exact Inversion Formula. The results obtained from the Exact Inversion Formula showed better image contrast and sharpness, and shorter computational time compared to the Expectation Maximization Algorithm.

  4. 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.

  5. Simultaneous Tc-99m/I-123 Dual Radionuclide Myocardial Perfusion/Innervation Imaging Using Siemens IQ-SPECT with SMARTZOOM Collimator

    PubMed Central

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric. C.

    2014-01-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region compared to a typical parallel-hole low-energy high-resolution collimator but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulation and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter modeling

  6. Concordance between (99m)Tc-ECD SPECT and 18F-FDG PET interpretations in patients with cognitive disorders diagnosed according to NIA-AA criteria.

    PubMed

    Ito, Kimiteru; Shimano, Yasumasa; Imabayashi, Etsuko; Nakata, Yasuhiro; Omachi, Yoshie; Sato, Noriko; Arima, Kunimasa; Matsuda, Hiroshi

    2014-10-01

    The purpose of this study was to clarify the concordance of diagnostic abilities and interobserver agreement between 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and brain perfusion single photon-emission computed tomography (SPECT) in patients with Alzheimer's disease (AD) who were diagnosed according to the research criteria of the National Institute of Aging-Alzheimer's Association Workshop. Fifty-five patients with "AD and mild cognitive impairment (MCI)" (n = 40) and "non-AD" (n = 15) were evaluated with 18F-FDG PET and (99m)Tc-ethyl cysteinate dimer (ECD) SPECT during an 8-week period. Three radiologists independently graded the regional uptake in the frontal, temporal, parietal, and occipital lobes as well as the precuneus/posterior cingulate cortex in both images. Kappa values were used to determine the interobserver reliability regarding regional uptake. The regions with better interobserver reliability between 18F-FDG PET and (99m)Tc-ECD SPECT were the frontal, parietal, and temporal lobes. The (99m)Tc-ECD SPECT agreement in the occipital lobes was not significant. The frontal, temporal, and parietal lobes showed good correlations between 18F-FDG PET and (99m)Tc-ECD SPECT in the degree of uptake, but the occipital lobe and precuneus/posterior cingulate cortex did not show good correlations. The diagnostic accuracy rates of "AD and MCI" ranged from 60% to 70% in both of the techniques. The degree of uptake on 18F-FDG PET and (99m)Tc-ECD SPECT showed significant correlations in the frontal, temporal, and parietal lobes. The diagnostic abilities of 18F-FDG PET and (99m)Tc-ECD SPECT for "AD and MCI," when diagnosed according to the National Institute of Aging-Alzheimer's Association Workshop criteria, were nearly identical. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Simultaneous Tc-99m/I-123 dual-radionuclide myocardial perfusion/innervation imaging using Siemens IQ-SPECT with SMARTZOOM collimator.

    PubMed

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric C

    2014-06-07

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region, compared to a typical parallel-hole low-energy high-resolution collimator, but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator-detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulations and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single-radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter

  8. Contribution of early SPECT/CT to (99m)Tc-MIBI double phase scintigraphy in primary hyperparathyroidism: Diagnostic value and correlation between uptake and biological parameters.

    PubMed

    García-Talavera, P; Díaz-Soto, G; Montes, A A; Villanueva, J G; Cobo, A; Gamazo, C; Ruiz, M Á; González-Selma, M L

    To evaluate the value of (99m)Tc-MIBI double-phase scintigraphy (DPS) and early SPECT/CT in the pre-surgical assessment of patients with primary hyperparathyroidism (PHPT). Also, to calculate the correlation between uptake and some biological parameters. Forty patients with PHPT were included: 37 solitary adenomas, 1 hyperplasia, and 2 double adenomas. Fifteen patients had ectopic glands. DPS and early SPECT/CT were acquired in all patients. Ultrasound was performed in 31/40. All patients underwent surgery, intra-operative iPTH measurements, and histopathological examinations. Qualitative DPS uptake was assessed and correlated to pre-surgical calcium, iPTH levels, gland weight, and maximum diameter. In the planar study, there were 23 positive cases, 8 doubtful, and 9 negatives. With the SPECT/CT, 8/9 negatives cases were located. All doubtful cases were confirmed as positives. Gland location improved in 16 cases (12 ectopic). DPS+SPECT/CT failed to detect a solitary adenoma and at least one gland in three cases of multiglandular disease (MGD). The sensitivity by patient was: DPS 72.5%, DPS+SPECT/CT 90%, and ultrasound 42%. Ultrasound and scintigraphy (DPS+SPECT/CT) were concordant in 16/31 patients. For the rest of them, scintigraphy proved correct in 14/15, and both techniques failed in one case. There was a significant correlation between level of uptake and iPTH level, gland weight, and maximum diameter. Early SPECT/CT improves sensitivity and the locating of parathyroid pathological glands and increases diagnostic confidence. iPTH level, glandular size, and weight are related to the qualitative assessment of (99m)Tc-MIBI uptake in early DPS. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  9. Simultaneous Tc-99m/I-123 dual-radionuclide myocardial perfusion/innervation imaging using Siemens IQ-SPECT with SMARTZOOM collimator

    NASA Astrophysics Data System (ADS)

    Du, Yong; Bhattacharya, Manojeet; Frey, Eric C.

    2014-06-01

    Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the cardiac region, compared to a typical parallel-hole low-energy high-resolution collimator, but without the data truncation that can result with conventional converging-beam collimators. The increased sensitivity allows shorter image acquisition times or reduced patient dose, making IQ-SPECT ideal for simultaneous dual-radionuclide SPECT, where reduced administrated activity is desirable in order to reduce patient radiation exposure. However, crosstalk is a major factor affecting the image quality in dual-radionuclide imaging. In this work we developed a model-based method that can estimate and compensate for the crosstalk in IQ-SPECT data. The crosstalk model takes into account interactions in the object and collimator-detector system. Scatter in the object was modeled using the effective source scatter estimation technique (ESSE), previously developed to model scatter with parallel-hole collimators. The geometric collimator-detector response was analytically modeled in the IQ-SPECT projector. The estimated crosstalk was then compensated for in an iterative reconstruction process. The new method was validated with data from both Monte Carlo simulations and physical phantom experiments. The results showed that the estimated crosstalk was in good agreement with simulated and measured results. After model-based compensation the images from simultaneous dual-radionuclide acquisitions were similar in quality to those from single-radionuclide acquisitions that did not have crosstalk contamination. The proposed model-based method can be used to improve simultaneous dual-radionuclide images acquired using IQ-SPECT. This work also demonstrates that ESSE scatter

  10. Three-Dimensional Dosimetric Analysis and Quantitative Bremsstrahlung Spect Imaging for Treatment of Non-Resectable Pancreatic Cancer Using Colloidal PHOSPHORUS-32.

    NASA Astrophysics Data System (ADS)

    Parsai, E. Ishmael

    1995-01-01

    Current methods of calculating absorbed dose in tissue from beta emitting radiopharmaceuticals yield only estimates of the average dose and cannot be used for dose mapping of bremsstrahlung SPECT images. The present work describes a clinically applicable methodology that can be used to determine the 3-D absorbed dose distribution from bremsstrahlung SPECT images for patients undergoing infusional brachytherapy. The radiopharmaceutical used in this study was colloidal P-32; however, other beta emitters can be used with this method. Calibration curves were generated from phantom studies to determine the activity per voxel from the attenuation corrected measured counts per voxel. The cumulative activity at each voxel position was converted to dose (Gy) using a Monte Carlo based P -32 point dose kernel calculation in water. Two-dimensional isodose distributions then were generated and projected on the reconstructed SPECT slices. This technique was further extended to calculate the quantitative dose for the entire volume and iso-surface dose distributions were generated in 3-D from bremsstrahlung SPECT data. In addition, to calculate the dose rate or accumulated dose at any depth from a given activity, a computer program based on the modified Loevinger point function was developed. This program calculates the dose in two ways: (1) through a closed solution for the spherical geometry by integration of the function over small spherical volumes, or (2) by applying the revised parameters of the modified Loevinger function. A practical and clinically feasible technique was developed for 3-D image co-registration between CT and SPECT for direct anatomic confirmation of the correlation between the region of the P-32 activity distribution and the anatomic site of injection. The method provides the correlation of the body contours obtained from bremsstrahlung SPECT data with corresponding contours from CT. A 3-D surface was first generated by mapping the iso-counts in the SPECT

  11. [The development and application in clinical programme of SPECT].

    PubMed

    Sun, Li-ming; Liu, Chen-bin

    2002-11-01

    On the base of original computer software of Elscint Apex 609 RG SPECT, two clinical application programmes are successfully designed for clinical engineers to explore and practise by using the CLIP (The Clinical Interpreter Programming) language.

  12. Performance evaluation of advanced industrial SPECT system with diverging collimator.

    PubMed

    Park, Jang Guen; Jung, Sung-Hee; Kim, Jong Bum; Moon, Jinho; Yeom, Yeon Soo; Kim, Chan Hyeong

    2014-12-01

    An advanced industrial SPECT system with 12-fold-array diverging collimator was developed for flow visualization in industrial reactors and was discussed in the previous study. The present paper describes performance evaluation of the SPECT system under both static- and dynamic- flow conditions. Under static conditions, the movement of radiotracer inside the test reactor was compared with that of color tracer (blue ink) captured with a high-speed camera. The comparison of the reconstructed images obtained with the radiotracer and the SPECT system showed fairly good agreement with video-frames of the color tracer obtained with the camera. Based on the results of the performance evaluation, it is concluded that the SPECT system is suitable for investigation and visualization of flows in industrial flow reactors.

  13. Initial Investigation of Preclinical Integrated SPECT and MR Imaging

    PubMed Central

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

    2014-01-01

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

  14. Sequential SPECT/CT imaging starting with stress SPECT in patients with left bundle branch block suspected for coronary artery disease.

    PubMed

    Engbers, Elsemiek M; Timmer, Jorik R; Mouden, Mohamed; Knollema, Siert; Jager, Pieter L; Ottervanger, Jan Paul

    2017-01-01

    To investigate the impact of left bundle branch block (LBBB) on sequential single photon emission computed tomography (SPECT)/ CT imaging starting with stress-first SPECT. Consecutive symptomatic low- to intermediate-risk patients without a history of coronary artery disease (CAD) referred for SPECT/CT were included from an observational registry. If stress SPECT was abnormal, additional rest SPECT and, if feasible, coronary CT angiography (CCTA) were acquired. Of the 5,018 patients, 218 (4.3 %) demonstrated LBBB. Patients with LBBB were slightly older than patients without LBBB (65±12 vs. 61±11 years, p<0.001). Stress SPECT was more frequently abnormal in patients with LBBB (82 % vs. 46 %, p<0.001). After reviewing stress and rest images, SPECT was normal in 43 % of the patients with LBBB, compared to 77 % of the patients without LBBB (p<0.001). Sixty-four of the 124 patients with LBBB and abnormal stress-rest SPECT underwent CCTA (52 %), which could exclude obstructive CAD in 46 of the patients (72 %). Sequential SPECT/CT imaging starting with stress SPECT is not the optimal imaging protocol in patients with LBBB, as the majority of these patients have potentially false-positive stress SPECT. First-line testing using CCTA may be more appropriate in low- to intermediate-risk patients with LBBB. • Stress-first SPECT imaging is attractive if many patients demonstrate normal stress perfusion. • The majority of left bundle branch block patients have abnormal stress-first SPECT. • Coronary CT excluded obstructive CAD in many LBBB patients with abnormal SPECT. • Stress-first SPECT imaging is not the optimal imaging protocol in LBBB patients. • In LBBB patients imaging with initial coronary CT may be more appropriate.

  15. Comparison of occupational radiation exposure from myocardial perfusion imaging with Rb-82 PET and Tc-99m SPECT.

    PubMed

    Tout, Deborah; Davidson, Gillian; Hurley, Caroline; Bartley, Michelle; Arumugam, Parthiban; Bradley, Andy

    2014-10-01

    Rubidium-82 (Rb-82) PET myocardial perfusion imaging (MPI) has superior diagnostic accuracy, at least similar prognostic value, and lower patient radiation exposure when compared with technetium-99m single-photon emission computed tomography (Tc-99m SPECT) MPI. The aim of this study was to compare occupational radiation exposure from the two modalities and show that improvements for the patient do not come at a cost to staff. Electronic personal dosimeters were worn by staff involved in the administration and imaging of routine clinical Tc-99m SPECT and Rb-82 PET MPI, and during tracer production and QC. To estimate dose to the staff in the event of a medical emergency, a survey meter was placed in close contact with the patient during Rb-82 infusion and imaging, and immediately after administration for Tc-99m SPECT. Mean (SD) whole-body effective dose to staff during a single MPI procedure was 0.4 (0.4) μSv for Rb-82 PET (1110 MBq) and 3.3 (1.7) μSv for Tc-99m SPECT (350 MBq). Staff effective dose during tracer production and QC was low (<0.2 μSv/patient) and comparable between tracers. An additional effective dose was measured at close contact to the patient during, and immediately after, tracer administration, although this will not pose a significant radiation risk to staff with either technique as long as this is not routine practice. There is a significant reduction in effective dose during Rb-82 PET when compared with Tc-99m SPECT MPI because of the short half-life of Rb-82 and reduced patient contact.

  16. ACR testing of a dedicated head SPECT unit.

    PubMed

    Sensakovic, William F; Hough, Matthew C; Kimbley, Elizabeth A

    2014-07-08

    Physics testing necessary for program accreditation is rigorously defined by the ACR. This testing is easily applied to most conventional SPECT systems based on gamma camera technology. The inSPira HD is a dedicated head SPECT system based on a rotating dual clamshell design that acquires data in a dual-spiral geometry. The unique geometry and configuration force alterations of the standard ACR physics testing protocol. Various tests, such as intrinsic planar uniformity and/or resolution, do not apply. The Data Spectrum Deluxe Phantom used for conventional SPECT testing cannot fit in the inSPira HD scanner bore, making (currently) unapproved use of the Small Deluxe SPECT Phantom necessary. Matrix size, collimator type, scanning time, reconstruction method, and attenuation correction were all varied from the typically prescribed ACR instructions. Visible spheres, sphere contrast, visible rod groups, uniformity, and root mean square (RMS) noise were measured. The acquired SPECT images surpassed the minimum ACR requirements for both spatial resolution (9.5 mm spheres resolved) and contrast (6.4 mm rod groups resolved). Sphere contrast was generally high. Integral uniformity was 4% and RMS noise was 1.7%. Noise appeared more correlated than in images from a conventional SPECT scanner. Attenuation-corrected images produced from direct CT scanning of the phantom and a manufacturer supplied model of the phantom demonstrated negligible differences.

  17. Review and current status of SPECT scatter correction

    NASA Astrophysics Data System (ADS)

    Hutton, Brian F.; Buvat, Irène; Beekman, Freek J.

    2011-07-01

    Detection of scattered gamma quanta degrades image contrast and quantitative accuracy of single-photon emission computed tomography (SPECT) imaging. This paper reviews methods to characterize and model scatter in SPECT and correct for its image degrading effects, both for clinical and small animal SPECT. Traditionally scatter correction methods were limited in accuracy, noise properties and/or generality and were not very widely applied. For small animal SPECT, these approximate methods of correction are often sufficient since the fraction of detected scattered photons is small. This contrasts with patient imaging where better accuracy can lead to significant improvement of image quality. As a result, over the last two decades, several new and improved scatter correction methods have been developed, although often at the cost of increased complexity and computation time. In concert with (i) the increasing number of energy windows on modern SPECT systems and (ii) excellent attenuation maps provided in SPECT/CT, some of these methods give new opportunities to remove degrading effects of scatter in both standard and complex situations and therefore are a gateway to highly quantitative single- and multi-tracer molecular imaging with improved noise properties. Widespread implementation of such scatter correction methods, however, still requires significant effort.

  18. Quantitative pulmonary single photon emission computed tomography (SPECT) with radiotherapy applications

    NASA Astrophysics Data System (ADS)

    Scarfone, Christopher

    1998-09-01

    The potential benefits of single photon emission computed tomography (SPECT) lung perfusion imaging for 3- dimensional radiation treatment planning and dose- response analysis, are currently being investigated. Accurate and precise SPECT quantification may facilitate the development of models to predict radiation-induced pulmonary dysfunction prior to treatment. The purpose of this research was to quantitatively evaluate the accuracy and precision of SPECT filtered backprojection (FBP) and maximum likelihood-expectation maximization (ML-EM) image reconstruction methods for measuring absolute and relative activity concentration estimates in the lungs. The investigation is conducted using Monte Carlo simulation and validation, experimental phantom studies and applications to patient data. The scatter response function and scatter fraction (SF) for the lung is measured using Monte Carlo simulation and experimental imaging of point and line sources surrounded by lung density media. The Monte Carlo (experimental) SF value for lung density material is determined to be 14.86% (14.01%) for the line source and 18.88% (20.32%) for the point source. Quantitative experimental evaluation of FBP and ML-EM reconstruction techniques is performed using an anthropomorphic torso phantom containing spherical defects (simulating areas of reduced perfusion) of inner diameters 1.4 cm, 3.4 cm, and 5.6 cm at sphere:background concentration ratios of 0:1, 0.38:1, 0.47:1, 0.51:1, 0.70:1. Quantification is examined as a function of attenuation, scatter constant (k, range = 0.45 to 2.00), total iteration number (5 → 500) and deconvolution (Metz) filter power (X, range = 2.0 to 10.0). Relative (to lung background) and absolute quantification is performed using region of interest (ROI) analysis. A dependence of quantitative accuracy on both defect diameter and density is observed. In general, percent bias increases as defect diameter and density decrease. Also, negative bias in the lung

  19. Radiation dose estimate in small animal SPECT and PET.

    PubMed

    Funk, Tobias; Sun, Mingshan; Hasegawa, Bruce H

    2004-09-01

    Calculations of radiation dose are important in assessing the medical and biological implications of ionizing radiation in medical imaging techniques such as SPECT and PET. In contrast, radiation dose estimates of SPECT and PET imaging of small animals are not very well established. For that reason we have estimated the whole-body radiation dose to mice and rats for isotopes such as 18F, 99mTc, 201Tl, (111)In, 123I, and 125I that are used commonly for small animal imaging. We have approximated mouse and rat bodies with uniform soft tissue equivalent ellipsoids. The mouse and rat sized ellipsoids had a mass of 30 g and 300 g, respectively, and a ratio of the principal axes of 1:1:4 and 0.7:1:4. The absorbed fractions for various photon energies have been calculated using the Monte Carlo software package MCNP. Using these values, we then calculated MIRD S-values for two geometries that model the distribution of activity in the animal body: (a) a central point source and (b) a homogeneously distributed source, and compared these values against S-value calculations for small ellipsoids tabulated in MIRD Pamphlet 8 to validate our results. Finally we calculated the radiation dose taking into account the biological half-life of the radiopharmaceuticals and the amount of activity administered. Our calculations produced S-values between 1.06 x 10(-13) Gy/Bq s and 2.77 x 10(-13) Gy/Bq s for SPECT agents, and 15.0 x 10(-13) Gy/Bq s for the PET agent 18F, assuming mouse sized ellipsoids with uniform source distribution. The S-values for a central point source in an ellipsoid are about 10% higher than the values obtained for the uniform source distribution. Furthermore, the S-values for mouse sized ellipsoids are approximately 10 times higher than for the rat sized ellipsoids reflecting the difference in mass. We reviewed published data to obtain administered radioactivity and residence times for small animal imaging. From these values and our computed S-values we estimated

  20. A prospective comparison of rubidium-82 PET and thallium-201 SPECT myocardial perfusion imaging utilizing a single dipyridamole stress in the diagnosis of coronary artery disease

    SciTech Connect

    Go, R.T.; Marwick, T.H.; MacIntyre, W.J.; Saha, G.B.; Neumann, D.R.; Underwood, D.A.; Simpfendorfer, C.C. )

    1990-12-01

    The purpose of the present study is to prospectively compare myocardial perfusion imaging with rubidium-82 ({sup 82}Rb) by positron emission tomography (PET) with thallium-201 ({sup 201}Tl) imaging by single-photon emission tomography (SPECT) by recording both studies with a single dipyridamole handgrip stress, and reading both sets of images with the same display technique. In a series of 202 patients with previous coronary arteriography, the sensitivity, specificity, and accuracy of {sup 82}Rb PET were 93%, 78%, and 90% and for {sup 201}Tl SPECT 76%, 80%, and 77%, respectively. When 70 patients with previous therapeutic interventions were excluded, the remaining 132 patients showed a sensitivity, specificity, and accuracy of 95%, 82% and 92% for {sup 82}Rb PET and 79%, 76%, and 78% for {sup 201}Tl SPECT. The improved contrast resolution of PET resulted in markedly superior images and a more confident identification of defects.

  1. Development of a Germanium Small-Animal SPECT System

    PubMed Central

    Johnson, Lindsay C.; Ovchinnikov, Oleg; Shokouhi, Sepideh; Peterson, Todd E.

    2015-01-01

    Advances in fabrication techniques, electronics, and mechanical cooling systems have given rise to germanium detectors suitable for biomedical imaging. We are developing a small-animal SPECT system that uses a double-sided Ge strip detector. The detector’s excellent energy resolution may help to reduce scatter and simplify processing of multi-isotope imaging, while its ability to measure depth of interaction has the potential to mitigate parallax error in pinhole imaging. The detector’s energy resolution is <1% FWHM at 140 keV and its spatial resolution is approximately 1.5 mm FWHM. The prototype system described has a single-pinhole collimator with a 1-mm diameter and a 70-degree opening angle with a focal length variable between 4.5 and 9 cm. Phantom images from the gantry-mounted system are presented, including the NEMA NU-2008 phantom and a hot-rod phantom. Additionally, the benefit of energy resolution is demonstrated by imaging a dual-isotope phantom with 99mTc and 123I without cross-talk correction. PMID:26755832

  2. [SPECT and FDG-PET in diagnostics of neurolues].

    PubMed

    Pichler, Robert; Doppler, Stefan; Szalay, Elisabeth; Hertl, Christine; Knell, Ulrich; Winkler, Johanna

    2008-01-01

    Syphilis is a recurrent treponematosis of acute and chronic evolution. In general it is either sexually or congenitally transmitted. Primary syphilis appears as a single and painless lesion. Secondary syphilis may manifest years later, the secondary bacteremic stage is accompanied by generalized mucocutaneous lesions. Tertiary disease can be disseminated to bones and virtually any organ, involving principally the ascending aorta and the central nervous system. Nuclear medicine provides diagnostic methods in case of skeletal manifestations by bone scan - identifying periostitis and osteomyelitis. Hepatic gummas can be imaged by 99m-Tc-colloid liver scintigraphy. In neurosyphilis brain perfusion SPECT enables imaging of cerebral involvement by small vessel endarteritis resulting from syphilitic vascular disease. 18-FDG PET is also useful to evaluate neurosyphilis, a reduction of brain glucose consumption is observed. The technique adequately enables imaging of therapeutic response and might be superior to morphologic imaging. We present our experiences with these nuclear medicine methods in patients with neurolues. The incidence of neurolues is estimated at 2 per 100.000 inhabitants worldwide, migration processes might bring a re-emergence of this disease to Austria and other developed countries of the EU. Scintigraphic methods should be kept in mind for diagnostic evaluation of neurosyphilis.

  3. Imaging the DNA damage response with PET and SPECT.

    PubMed

    Knight, James C; Koustoulidou, Sofia; Cornelissen, Bart

    2017-06-01

    DNA integrity is constantly challenged by endogenous and exogenous factors that can alter the DNA sequence, leading to mutagenesis, aberrant transcriptional activity, and cytotoxicity. Left unrepaired, damaged DNA can ultimately lead to the development of cancer. To overcome this threat, a series of complex mechanisms collectively known as the DNA damage response (DDR) are able to detect the various types of DNA damage that can occur and stimulate the appropriate repair process. Each DNA damage repair pathway leads to the recruitment, upregulation, or activation of specific proteins within the nucleus, which, in some cases, can represent attractive targets for molecular imaging. Given the well-established involvement of DDR during tumorigenesis and cancer therapy, the ability to monitor these repair processes non-invasively using nuclear imaging techniques may facilitate the earlier detection of cancer and may also assist in monitoring response to DNA damaging treatment. This review article aims to provide an overview of recent efforts to develop PET and SPECT radiotracers for imaging of DNA damage repair proteins.

  4. Changes in quantitative SPECT thallium-201 results associated with the use of energy-weighted acquisition

    SciTech Connect

    Floyd, J.L.; Mann, R.B.; Shaw, A. )

    1991-05-01

    The effect of utilizing energy-weighted acquisition on quantitative analysis of SPECT thallium-201 images was evaluated by simultaneously acquiring energy-weighted and windowed projection images in ten patients. The paired image sets were processed identically and evaluated by probability analysis of defect magnitude as indicated by a commercially available software analysis package. It was predicted that defect magnitude would increase as a result of improved image contrast. This was confirmed experimentally. One should be cautious in relying on strict quantitative criteria in cardiac studies with thallium-201, especially when major changes in the imaging system or technique are introduced.

  5. Comparison of 360 degrees and 180 degrees data collection in SPECT imaging.

    PubMed

    Knesaurek, K

    1987-11-01

    The problem of using 360 degrees or 180 degrees data sampling techniques in transaxial SPECT imaging is still to be solved. A theoretical point source study for an ideal response detector has shown, for objects which are close enough to the origin of the reconstructed area, that there are significant differences between sections obtained by different sampling methods. A computer simulation study of line sources in a homogeneous attenuated medium has confirmed the results of clinical studies in which significant image distortion has been observed in 180 degrees sections but not in 360 degrees reconstructed images.

  6. The Development and Initial Evaluation of a Realistic Simulated SPECT Dataset with Simultaneous Respiratory and Cardiac Motion for Gated Myocardial Perfusion SPECT

    PubMed Central

    Lee, Taek-Soo; Tsui, Benjamin M. W.

    2015-01-01

    We developed a realistic simulation dataset for simultaneous respiratory and cardiac (R&C) gated SPECT/CT using the 4D NURBS-based Cardiac-Torso (NCAT) Phantom and Monte Carlo simulation methods, and evaluated it for a sample application study. The 4D NCAT phantom included realistic respiratory motion and beating heart motion based on respiratory gated CT and cardiac tagged MRI data of normal human subjects. To model the respiratory motion, a set of 24 separate 3D NCAT phantoms excluding the heart was generated over a respiratory cycle. The beating heart motion was modelled separately with 48 frames per cardiac cycle for each of the 24 respiratory phases. The resultant set of 24×48 3D NCAT phantoms provides a realistic model of a normal human subject at different phases of combined R&C motions. An almost noise-free SPECT projection dataset for each of the 1,152 3D NCAT phantoms was generated using Monte Carlo simulation techniques and the radioactivity uptake distribution of 99mTc sestamibi in different organs. By grouping and summing the separate projection datasets, separate or simultaneous R&C gated acquired data with different gating schemes could be simulated. In the initial evaluation, we combined the projection datasets into no gating, 6 respiratory-gates only, 8 cardiac-gates only, and combined 6 respiratory-gates & 8 cardiac-gates projection datasets. Each dataset was reconstructed using 3D OS-EM without and with attenuation correction using the averaged and respiratory-gated attenuation maps, and the resulting reconstructed images were compared. These results were used to demonstrate the effects of R&C motions and the reduction of image artifact due to R&C motions by gating and attenuation corrections. We concluded that the realistic 4D NCAT phantom and Monte Carlo simulated SPECT projection datasets with R&C motions are powerful tools in the study of the effects of R&C motions, as well as in the development of R&C gating schemes and motion correction

  7. The development and initial evaluation of a realistic simulated SPECT dataset with simultaneous respiratory and cardiac motion for gated myocardial perfusion SPECT

    NASA Astrophysics Data System (ADS)

    Lee, Taek-Soo; Tsui, Benjamin M. W.

    2015-02-01

    We developed a realistic simulation dataset for simultaneous respiratory and cardiac (R&C) gated SPECT/CT using the 4D NURBS-based Cardiac-Torso (NCAT) Phantom and Monte Carlo simulation methods, and evaluated it for a sample application study. The 4D NCAT phantom included realistic respiratory motion and beating heart motion based on respiratory gated CT and cardiac tagged MRI data of normal human subjects. To model the respiratory motion, a set of 24 separate 3D NCAT phantoms excluding the heart was generated over a respiratory cycle. The beating heart motion was modeled separately with 48 frames per cardiac cycle for each of the 24 respiratory phases. The resultant set of 24  ×  48 3D NCAT phantoms provides a realistic model of a normal human subject at different phases of combined R&C motions. An almost noise-free SPECT projection dataset for each of the 1152 3D NCAT phantoms was generated using Monte Carlo simulation techniques and the radioactivity uptake distribution of 99mTc sestamibi in different organs. By grouping and summing the separate projection datasets, separate or simultaneous R&C gated acquired data with different gating schemes could be simulated. In the initial evaluation, we combined the projection datasets into ungated, 6 respiratory-gates only, 8 cardiac-gates only, and combined 6 respiratory-gates & 8 cardiac-gates projection datasets. Each dataset was reconstructed using 3D OS-EM without and with attenuation correction using the averaged and respiratory-gated attenuation maps, and the resulting reconstructed images were compared. These results were used to demonstrate the effects of R&C motions and the reduction of image artifact due to R&C motions by gating and attenuation corrections. We concluded that the realistic 4D NCAT phantom and Monte Carlo simulated SPECT projection datasets with R&C motions are powerful tools in the study of the effects of R&C motions, as well as in the development of R&C gating schemes and motion

  8. The development and initial evaluation of a realistic simulated SPECT dataset with simultaneous respiratory and cardiac motion for gated myocardial perfusion SPECT.

    PubMed

    Lee, Taek-Soo; Tsui, Benjamin M W

    2015-02-21

    We developed a realistic simulation dataset for simultaneous respiratory and cardiac (R&C) gated SPECT/CT using the 4D NURBS-based Cardiac-Torso (NCAT) Phantom and Monte Carlo simulation methods, and evaluated it for a sample application study. The 4D NCAT phantom included realistic respiratory motion and beating heart motion based on respiratory gated CT and cardiac tagged MRI data of normal human subjects. To model the respiratory motion, a set of 24 separate 3D NCAT phantoms excluding the heart was generated over a respiratory cycle. The beating heart motion was modeled separately with 48 frames per cardiac cycle for each of the 24 respiratory phases. The resultant set of 24  ×  48 3D NCAT phantoms provides a realistic model of a normal human subject at different phases of combined R&C motions. An almost noise-free SPECT projection dataset for each of the 1152 3D NCAT phantoms was generated using Monte Carlo simulation techniques and the radioactivity uptake distribution of (99m)Tc sestamibi in different organs. By grouping and summing the separate projection datasets, separate or simultaneous R&C gated acquired data with different gating schemes could be simulated. In the initial evaluation, we combined the projection datasets into ungated, 6 respiratory-gates only, 8 cardiac-gates only, and combined 6 respiratory-gates & 8 cardiac-gates projection datasets. Each dataset was reconstructed using 3D OS-EM without and with attenuation correction using the averaged and respiratory-gated attenuation maps, and the resulting reconstructed images were compared. These results were used to demonstrate the effects of R&C motions and the reduction of image artifact due to R&C motions by gating and attenuation corrections. We concluded that the realistic 4D NCAT phantom and Monte Carlo simulated SPECT projection datasets with R&C motions are powerful tools in the study of the effects of R&C motions, as well as in the development of R&C gating schemes and motion

  9. 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.

  10. Some physical factors influencing the accuracy of convolution scatter correction in SPECT.

    PubMed

    Msaki, P; Axelsson, B; Larsson, S A

    1989-03-01

    Some important physical factors influencing the accuracy of convolution scatter correction techniques in SPECT are presented. In these techniques scatter correction in the projection relies on filter functions, QF, evaluated by Fourier transforms, from measured scatter functions, Qp, obtained from point spread functions. The spatial resolution has a marginal effect on Qp. Thus a single QF can be used in the scatter correction of SPECT measurements acquired with the low energy high resolution or the low energy general purpose collimators and over a wide range of patient-collimator distances. However, it is necessary to examine the details of the shape of point spread functions during evaluation of Qp. QF is completely described by scatter amplitude AF, slope BF and filter sum SF. SF is obtained by summation of the values of QF occupying a 31 x 31 pixels matrix. Regardless of differences in amplitude and slope, two filter functions are shown to be equivalent in terms of scatter correction ability, whenever their sums are equal. On the basis of filter sum, the observed small influence of ellipticity on QF implies that an average function can be used in scatter correcting SPECT measurements conducted with elliptic objects. SF is shown to increase with a decrease in photon energy and with an increase in window size. Thus, scatter correction by convolution may be severely hampered by photon statistics when SPECT imaging is done with low-energy photons. It is pointless to use unnecessarily large discriminator windows, in the hope of improving photon statistics, since most of the extra events acquired will eventually be subtracted during scatter correction. Regardless of the observed moderate reduction in SF when a lung-equivalent material replaces a portion of a water phantom, further studies are needed to develop a technique that is capable of handling attenuation and scatter corrections simultaneously. Whenever superficial and inner radioactive distributions coexist the

  11. 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

  12. Dual Isotope SPECT Study With Epilepsy Patients Using Semiconductor SPECT System.

    PubMed

    Shiga, Tohru; Suzuki, Atsuro; Sakurai, Kotarou; Kurita, Tsugiko; Takeuchi, Wataru; Toyonaga, Takuya; Hirata, Kenji; Kobashi, Keiji; Katoh, Chietsugu; Kubo, Naoki; Tamaki, Nagara

    2017-09-01

    We developed a prototype CdTe SPECT system with 4-pixel matched collimator for brain study. This system provides high-energy-resolution (6.6%), high-sensitivity (220 cps/MBq/head), and high-spatial-resolution images. The aim of this study was to evaluate dual-isotope study of CBF and central benzodiazepine receptor (BZR) images using Tc-ECD and I-IMZ with the new SPECT system in patients with epilepsy comparing with single-isotope study using the conventional scintillation gamma camera. This study included 13 patients with partial epilepsy. The BZR images were acquired at 3 hours after I-IMZ injection for 20 minutes. The images of IMZ were acquired with a conventional 3-head scintillation gamma camera. After BZR image acquisition with the conventional camera, Tc-ECD was injected, and CBF and BZR images were acquired simultaneously 5 minutes after ECD injection with the new SPECT system. The CBF images were also acquired with the conventional camera on separate days. The findings were visually analyzed, and 3D-SSP maximum Z scores of lesions were compared between the 2 studies. There were 47 abnormal lesions on BZR images and 60 abnormal lesions on CBF images in the single-isotope study with the conventional camera. Dual-isotope study with the new system showed concordant abnormal findings of 46 of 47 lesions on BZR and 54 of 60 lesions on CBF images with the single-isotope study with the conventional camera. There was high agreement between the 2 studies in both BZR and CBF findings (Cohen κ values = 0.96 for BZR and 0.78 for CBF). In semiquantitative analysis, maximum Z scores of dual-isotope study with the new system strongly correlated with those of single-isotope study with the conventional camera (BZR: r = 0.82, P < 0.05, CBF: r = 0.87, P < 0.05). Our new SPECT system permits dual-isotope study for pixel-by-pixel analysis of CBF and BZR information with the same pathophysiological condition in patients with epilepsy.

  13. Steal phenomenon-induced lung perfusion defects in pulmonary arteriovenous fistulas: assessment with automated perfusion SPECT-CT fusion images.

    PubMed

    Suga, Kazuyoshi; Iwanaga, Hideyuki; Tokuda, Osamu; Okada, Munemasa; Tanaka, Nobuyuki; Matsunaga, Naofumi

    2010-09-01

    Lung perfusion impairment in patients with pulmonary arteriovenous fistula (AVF) was evaluated by automated deep inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images. Participants were 14 patients with a single (N=6) or multiple nodular AVFs (N=8) diagnosed by contrast-enhanced CT scan and/or pulmonary angiography. After the injection of 185MBq Tc-99m-macroaggregated albumin, a whole-body scan was obtained to quantify an intrapulmonary right-to-left shunt. Subsequently, DIBrH SPECT was obtained using the continuous rotating acquisition mode of a dual-headed SPECT system, which was automatically coregistered with DIBrH CT. The anatomic relationship between AVF and perfusion defects was assessed on the fusion images. The whole-body scan depicted systemic organs indicating the presence of an intrapulmonary right-to-left shunt in all the patients. DIBrH SPECT showed 34 perfusion defects in these patients, which were located at the AVF and in the surrounding lungs of the AVF on the fusion images, regardless of the absence of morphologic abnormality on CT in all the patients. These defects were considered to be caused by the 'steal phenomenon' associated with the high and fast pulmonary arterial flow to each AVF, which were more extensive and severe in the multiple AVFs compared with a single AVF (P=0.0012), occasionally extending to the entire lobe with AVF or even to the adjacent lobe. In five patients, the fusion images detected a total of six tiny AVFs with unexpectedly extensive 'steal phenomenon'-induced defects, which had been missed by other radiological imaging techniques. The summed value of the shunt index estimated by the whole-body scan and the lung perfusion defect extent estimated by DIBrH SPECT was significantly correlated with PaO2 in all the patients (P < 0.0001), with a better correlation compared with the shunt index alone. In addition to the right-to-left shunt, 'steal phenomenon

  14. Planar and SPECT ventilation/perfusion imaging and computed tomography for the diagnosis of pulmonary embolism: A systematic review and meta-analysis of the literature, and cost and dose comparison.

    PubMed

    Phillips, J J; Straiton, J; Staff, R T

    2015-07-01

    Diagnosing acute pulmonary embolism (PE) is an indication for scintillation V/Q imaging (planar and SPECT) and/or CTPA. This study reviews, compares and aggregates the published diagnostic performance of each modality and assesses the short-term consequences in terms of diagnostic outcomes, monetary cost, and radiation burden. We performed a formal literature review of available data and aggregated the finding using a summary receiver operating characteristic. A decision tree approach was used to estimate cost and dose per correct diagnosis. The review found 19 studies, which comprised 27 data sets (6393 examinations, from 5923 patients). The results showed that planar V/Q was significantly inferior to both V/Q SPECT and CTPA with no difference between the latter two. CTPA represents best value; £129 per correct diagnosis compared to £243 (SPECT) and £226 (planar). In terms of radiation burden V/Q SPECT was the most effective with a dose of 2.12 mSv per correct diagnosis compared with 3.46 mSv (planar) and 4.96 (CTPA) mSv. These findings show no performance difference between V/Q SPECT and CTPA; planar V/Q is inferior. CTPA is clearly the most cost effective technique. V/Q SPECT should be considered in situations where radiation dose is of concern or CTPA is inappropriate.

  15. Recent developments and future prospects of SPECT myocardial perfusion imaging.

    PubMed

    Zaman, Maseeh Uz; Hashmi, Ibrahim; Fatima, Nosheen

    2010-10-01

    Myocardial perfusion SPECT imaging is the most commonly performed functional imaging for assessment of coronary artery disease. High diagnostic accuracy and incremental prognostic value are the major benefits while suboptimal spatial resolution and significant radiation exposure are the main limitations. Its ability to detect hemodynamic significance of lesions seen on multidetector CT angiogram (MDCTA) has paved the path for a successful marriage between anatomical and functional imaging modalities in the form of hybrid SPECT/MDCTA system. In recent years, there have been enormous efforts by industry and academia to develop new SPECT imaging systems with better sensitivity, resolution, compact design and new reconstruction algorithms with ability to improve image quality and resolution. Furthermore, expected arrival of Tc-99m-labeled deoxyglucose in next few years would further strengthen the role of SPECT in imaging hibernating myocardium. In view of these developments, it seems that SPECT would enjoy its pivotal role in spite of major threat to be replaced by fluorine-18-labeled positron emission tomography perfusion and glucose metabolism imaging agents.

  16. 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.

  17. Multimodality tomographic scintimammography with PET, PECI, and SPECT: initial evaluation

    NASA Astrophysics Data System (ADS)

    Krol, Andrzej; Feiglin, David H.; Thomas, Frank D.; Hellwig, Bradford J.; Gagne, George M.

    2002-04-01

    We compared tomographic scintimammography performed using single photon emission computed tomography (SPECT), positron emission coincidence imaging (PECI) and positron emission tomography (PET). A female thorax phantom was used. Activities of the myocardium, thorax and breasts were adjusted to emulate the count rate observed with patients. Hollow plastic spheres, imitating hot lesions (1.5-20ml), filled with radioactive saline were inserted in the center of each breast. Specific activities of internal organs were adjusted to emulate the count rate observed with patients. SPECT data were acquired with Tc-99m using gamma cameras with NaI(Tl) detectors. A modified FBP (CODE) reconstruction algorithm was used to render SPECT tomographic images. PECI (Siemens E.CAM with NaI(Tl)) and PET (GE Advance with BGO) data were acquired using F-18 FDG. Vendor supplied reconstruction algorithms were used. The reconstructed hot lesions contrast and resolution were investigated. Image quality obtained can be ranked as follows: (1) PET(BGO), (2) PECI(NaI), (3) SPECT(NaI) In conclusion, assuming comparable uptake values of Tc-99m-sestamibi and F-18 FDG, PET seems to be a superior methodology in visualization of breast lesion as compared to SPECT and PECI. All these tomographic methods appear to be promising adjunct to x-ray mammography in difficult to interpret cases.

  18. Enhancing the utility of prostascint SPECT scans for patient management.

    PubMed

    Noz, Marilyn E; Chung, Grace; Lee, Benjamin Y; Maguire, Gerald Q; DeWyngaert, J Keith; Doshi, Jay V; Kramer, Elissa L; Murphy-Walcott, Antoinette D; Zeleznik, Michael P; Kwak, Noeun G

    2006-04-01

    This project investigated reducing the artifact content of In-ill ProstaScint SPECT scans for use in treatment planning and management. Forty-one patients who had undergone CT or MRI scans and simultaneous Tc-99m RBC/In-111 ProstaScint SPECT scans were included. SPECT volume sets, reconstructed using Ordered Set-Expectation Maximum (OS-EM) were compared against those reconstructed with standard Filtered Back projection (FBP). Bladder activity in Tc-99m scans was suppressed within an ellipsoidal volume. Tc-99m voxel values were subtracted from the corresponding In-111 after scaling based on peak activity within the descending aorta. The SPECT volume data sets were merged with the CT or MRI scans before and after processing. Volume merging, based both on visual assessment and statistical evaluation, was not affected. Thus iterative reconstruction together with bladder suppression and blood pool subtraction may improve the interpretation and utility of ProstaScint SPECT scans for patient management.

  19. Three-dimensional SPECT imaging with LaBr3:Ce scintillator for characterization of nuclear waste

    NASA Astrophysics Data System (ADS)

    Roy, Tushar; Ratheesh, Jilju; Sinha, Amar

    2014-01-01

    Characterization of nuclear waste in terms of radioactivity distribution is important not only for their safe disposal but also for nuclear material accounting. Single Photon Emission Computed Tomography (SPECT) provides a non-invasive technique for the characterization and activity distribution of the gamma-emitting sources in a matrix. Sodium iodide scintillators, which are most commonly used, suffer from poor energy resolution and do not provide accurate peak discrimination for radioisotopes like 239Pu which have overlapping peaks. Cerium-activated lanthanum bromide (LaBr3:Ce) scintillators have better energy resolution and provide better peak discrimination. In this paper, experimental studies using LaBr3:Ce for 3D SPECT imaging of dummy waste drum has been discussed. The reconstruction has been done using the Filtered Backprojection scheme with attenuation compensation based on Novikov's inversion formula.

  20. Multimodal sentinel lymph node mapping with single-photon emission computed tomography (SPECT)/computed tomography (CT) and photoacoustic tomography.

    PubMed

    Akers, Walter J; Edwards, W Barry; Kim, Chulhong; Xu, Baogang; Erpelding, Todd N; Wang, Lihong V; Achilefu, Samuel

    2012-03-01

    The identification of cancer cells in the lymph nodes surrounding a tumor is important in establishing a prognosis. Optical detection techniques such as fluorescence and photoacoustic tomography (PAT) have been reported in preclinical studies for noninvasive sentinel lymph node (SLN) mapping. A method for validation of these techniques is needed for clinical trials. We report the use of a multimodal optical-radionuclear contrast agent as a validation tool for PAT in a preclinical model. Methylene blue (MB) was radiolabeled with (125)I for multimodal SLN mapping and used in conjunction with MB to assess the feasibility of multimodal SLN mapping in a rat model by PAT and single-photon emission computed tomography (SPECT). MB provided sufficient contrast for identifying SLNs noninvasively with a PAT system adapted from a clinical ultrasound imaging system. The signal location was corroborated by SPECT using (125)I labeled MB. The translation of PAT into the clinic can be facilitated by a direct comparison with established imaging methods using a clinically relevant dual SPECT and photoacoustic imaging agent. The new high-resolution PAT is a promising technology for the sensitive and accurate SLN detection in cancer patients. Copyright © 2012 Mosby, Inc. All rights reserved.

  1. Quantitative assessment of rest and acetazolamide CBF using quantitative SPECT reconstruction and sequential administration of (123)I-iodoamphetamine: comparison among data acquired at three institutions.

    PubMed

    Yamauchi, Miho; Imabayashi, Etsuko; Matsuda, Hiroshi; Nakagawara, Jyoji; Takahashi, Masaaki; Shimosegawa, Eku; Hatazawa, Jun; Suzuki, Michiyasu; Iwanaga, Hideyuki; Fukuda, Kenji; Iihara, Koji; Iida, Hidehiro

    2014-11-01

    A recently developed technique which reconstructs quantitative images from original projection data acquired using existing single-photon emission computed tomography (SPECT) devices enabled quantitative assessment of cerebral blood flow (CBF) at rest and after acetazolamide challenge. This study was intended to generate a normal database and to investigate its inter-institutional consistency. The three institutions carried out a series of SPECT scanning on 32 healthy volunteers, following a recently proposed method that involved dual administration of (123)I-iodoamphetamine during a single SPECT scan. Intra-institute and inter-institutional variations of regional CBF values were evaluated both at rest and after acetazolamide challenge. Functional images were pooled for both rest and acetazolamide CBF, and inter-institutional difference was evaluated among these images using two independent software programs. Quantitative assessment of CBF images at rest and after acetazolamide was successfully achieved with the given protocol in all institutions. Intra-institutional variation of CBF values at rest and after acetazolamide was consistent with previously reported values. Quantitative CBF values showed no significant difference among institutions in all regions, except for a posterior cerebral artery region after acetazolamide challenge in one institution which employed SPECT device with lowest spatial resolution. Pooled CBF images at rest and after acetazolamide generated using two software programs showed no institutional differences after equalization of the spatial resolution. SPECT can provide reproducible images from projection data acquired using different SPECT devices. A common database acquired at different institutions may be shared among institutions, if images are reconstructed using a quantitative reconstruction program, and acquired by following a standardized protocol.

  2. Microdosing, imaging biomarkers and SPECT: a multi-sided tripod to accelerate drug development.

    PubMed

    Pauwels, Ernest K J; Bergstrom, Kim; Mariani, Giuliano; Kairemo, Kalevi

    2009-01-01

    The advances of nuclear medicine imaging instrumentation and radiopharmaceutical sciences allow their involvement in the developmental processes of therapeutic drugs. New chemical entities, meant as potential drugs, need to comply with the proof-of-principle. Tomographic imaging methods as PET, SPECT and CT have been used for small animal and human studies at an early stage of drug development. Using a drug candidate in a radiolabeled form in obtaining quantitative imaging data provides opportunity for a complete morphological and functional overview of targeting properties and overall pharmacokinetics. This can be helpful in go/no-go decision making. Microdosing, using e.g.1% of the proposed dose of the radiolabeled potential drug plays an important part in this early development and notably reduces the risk of serious adverse effects in human volunteers or patients. This paper primarily focuses on the way in which microdosing and SPECT imaging may contribute to the development of drugs. Furthermore, this paper illustrates how these techniques may help to eliminate weak drug candidates at early stage, making time and funds available for potential lead compounds. Eventually this approach facilitates and accelerates new drug approval. The present paper highlights how these techniques make drug development easier in the field of oncology and neurology.

  3. 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.

  4. Dopamine D2 receptor status assessed by IBZM SPECT - A sensitive indicator for cerebral hypoxia

    SciTech Connect

    Tatsch, K.; Schwarz, J.; Welz, A.

    1995-05-01

    The striatum is highly sensitive to tissue hypoxia. Thus, it may be suggested that cerebral hypoxia could affect the integrity of the striatal receptor system. Purpose of the current SPECT investigations with IBZM was to evaluate whether hypoxic conditions cause detectable changes in the D2 receptor status. 25 controls and 30 pts with history of cerebral hypoxia (resuscitation after cardiac arrest: n=19, CABG surgery under cardiopulmonary bypass: n=11) were investigated with SPECT 2h p.i. of 185 MBq I-123 IBZM. For semiquant, evaluation transverse slices corrected for attenuation were used to calculate striatal to frontal cortex (S/FC) ratios. In 13/19 pts with cerebral hypoxia due to cardiac arrest IBZM binding was severely reduced after successful resuscitation. 7 died, 5 were in a vegetative state, 1 remained severely disabled. In 6/19 S/FC ratios were normal/mildly reduced, 2 of them had a good outcome, 4 were moderatley disabled. In pts with CABG IBZM binding was preoperatively normal. After hypoxia due to cardiac surgery striatal S/FC ratios decreased slightly, persisting on this level even 6 months after surgery. Neuropsychological/psychiatric testing showed only minor or transient changes in this group of patients. The striatal D2 receptor status seems to be a sensitive indicator for cerebral hypoxia. After hypoxia due to cardiac arrest IBZM results well correlate (in contrast to morphological or SEP findings) with the clinical outcome and thus may serve as early predictor of the individual prognosis. The moderate decline in IBZM binding following CABG surgery suggests mild cerebral hypoxia despite of protective hypothermia. Sensitively indicating cerebral hypoxia changes in the D2 receptor status assessed by IBZM SPECT may serve as a valuable diagnostic tool for testing neuroprotective drugs or modified surgical techniques.

  5. Development and validation of a Monte Carlo simulation tool for multi-pinhole SPECT.

    PubMed

    Mok, Greta S P; Du, Yong; Wang, Yuchuan; Frey, Eric C; Tsui, Benjamin M W

    2010-06-01

    In this work, we developed and validated a Monte Carlo simulation (MCS) tool for investigation and evaluation of multi-pinhole (MPH) SPECT imaging. 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. 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. 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.

  6. Preconditioned alternating projection algorithm for solving the penalized-likelihood SPECT reconstruction problem.

    PubMed

    Li, Si; Zhang, Jiahan; Krol, Andrzej; Schmidtlein, C Ross; Feiglin, David; Xu, Yuesheng

    2017-06-01

    The authors recently developed a preconditioned alternating projection algorithm (PAPA) for solving the penalized-likelihood SPECT reconstruction problem. The proposed algorithm can solve a wide variety of non-differentiable optimization models. This work is dedicated to comparing the performance of PAPA with total variation (TV) regularization (TV-PAPA) and a novel forward-backward algorithm with nested expectation maximization (EM)-TV iteration scheme (FB-EM-TV). Monte Carlo technique was used to simulate multiple noise realizations of the fan-beam collimated SPECT data for a piecewise constant phantom with warm background, and hot and cold spheres with uniform activities at two noise levels. They were reconstructed using the aforementioned algorithms with attenuation, scatter, distance-dependent collimator blurring and sensitivity corrections. Noise suppressing performance, lesion detectability, lesion contrast, contrast recovery coefficient, convergence speed and selection of optimal parameters were evaluated. The conventional EM algorithms with TV post-filter (TVPF-EM) and Gaussian post-filter (GPF-EM) were used as benchmarks. The TV-PAPA and FB-EM-TV demonstrated similar performance in all investigated categories. Both algorithms outperformed TVPF-EM in terms of image noise suppression, lesion detectability, lesion contrast and convergence speed. We established that the optimal parameters versus information density approximately followed power laws, which offers a guidance in parameter selection for reconstruction methods. For the simulated SPECT data, TV-PAPA and FB-EM-TV produced qualitatively and quantitatively similar images. They performed better than the benchmark TVPF-EM and GPF-EM, with only limited loss of lesion contrast. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  7. Quantitation of renal uptake of technetium-99m DMSA using SPECT

    SciTech Connect

    Groshar, D.; Frankel, A.; Iosilevsky, G.; Israel, O.; Moskovitz, B.; Levin, D.R.; Front, D.

    1989-02-01

    Quantitative single photon emission computed tomography (SPECT) methodology based on calibration with kidney phantoms has been applied for the assessment of renal uptake of (/sup 99m/Tc)DMSA in 25 normals; 16 patients with a single normal kidney; 30 patients with unilateral nephropathy; and 17 patients with bilateral nephropathy. An excellent correlation (r = 0.99, s.e.e. = 152) was found between SPECT measured concentration and actual concentration in kidney phantoms. Kidney uptake at 6 hr after injection in normals was 20.0% +/- 4.6% for the left and 20.8% +/- 4.4% for the right. Patients with unilateral nephropathy had a statistically significant (p less than 0.001) low uptake in the diseased kidney (7.0% +/- 4.7%), but the contralateral kidney uptake did not differ from the normal group (20.0% +/- 7.0%). The method was especially useful in patients with bilateral nephropathy. Significantly (p less than 0.001) decreased uptake was found in both kidneys (5.1% +/- 3.4% for the left and 6.7% +/- 4.2% for the right). The total kidney uptake (right and left) in this group showed to be inversely correlated (r = 0.83) with serum creatinine. The uptake of (/sup 99m/Tc)DMSA in single normal kidney was higher (p less than 0.001) than in a normal kidney (34.7% +/- 11.9%), however, it was lower than the total absolute uptake (RT + LT = 41.5% +/- 8.8%) in the normal group. The results indicate that SPECT is a reliable and reproducible technique to quantitate absolute kidney uptake of (/sup 99m/Tc)DMSA.

  8. MULTIMODALITY IMAGING: BEYOND PET/CT AND SPECT/CT

    PubMed Central

    Cherry, Simon R.

    2009-01-01

    Multimodality imaging with PET/CT and SPECT/CT has become commonplace in clinical practice and in preclinical and basic medical research. Do other combinations of imaging modalities have a similar potential to impact medical science and clinical medicine? The combination of PET or SPECT with MRI is an area of active research at the present time, while other, perhaps less obvious combinations, including CT/MR and PET/optical also are being studied. In addition to the integration of the instrumentation, there are parallel developments in synthesizing imaging agents that can be viewed by multiple imaging modalities. Is the fusion of PET and SPECT with CT the ultimate answer in multimodality imaging, or is it just the first example of a more general trend towards harnessing the complementary nature of the different modalities on integrated imaging platforms? PMID:19646559

  9. Determination of left ventricular mass through SPECT imaging

    SciTech Connect

    Zarate-Morales, A.; Rodriguez-Villafuerte, M.; Martinez-Rodriguez, F.; Arevila-Ceballos, N.

    1998-08-28

    An edge detection algorithm has been applied to estimate left ventricular (LV) mass from single photon emission computed tomography (SPECT) thallium-201 images. The algorithm was validated using SPECT images of a phantom. The algorithm was applied to 20 patient studies from the Hospital de Cardiologia, Centro Medico Nacional Siglo XXI. Left ventricular masses derived from the stress and redistribution studies were highly correlated (r=0.96). The average LV masses obtained were 162{+-}37 g and 169{+-}34 g in the redistribution and stress studies, respectively.

  10. Determination of left ventricular mass through SPECT imaging

    NASA Astrophysics Data System (ADS)

    Zárate-Morales, A.; Rodríguez-Villafuerte, M.; Martínez-Rodríguez, F.; Arévila-Ceballos, N.

    1998-08-01

    An edge detection algorithm has been applied to estimate left ventricular (LV) mass from single photon emission computed tomography (SPECT) thallium-201 images. The algorithm was validated using SPECT images of a phantom. The algorithm was applied to 20 patient studies from the Hospital de Cardiologia, Centro Médico Nacional Siglo XXI. Left ventricular masses derived from the stress and redistribution studies were highly correlated (r=0.96). The average LV masses obtained were 162±37 g and 169±34 g in the redistribution and stress studies, respectively.

  11. What do practice policies have to do with SPECT imaging?

    SciTech Connect

    Pierson, R.N. Jr.

    1991-12-31

    The introduction of new technologies has been the hallmark of professionals in nuclear medicine from the beginning of our specialty less than 50 years ago. A side effect of the entrenched and productive scenario whereby new technologies beget medical advances, and most of the advances in other areas of science beget new technologies applicable to medicine, is a constant escalation of the scope of practice, a desirable effect. A second side effect is a constant escalation of the cost of providing medical care. Careful analyses of the increases in costs of medical care allocate approximately one-third of the increase to new technology. We require mechanisms to argue competitively for the utility, the effectiveness, and the global relevance of new technologies. The first audience to be reached is the professionals who will, if we are successful, learn what we can do, and then will ask that it be made available in their hospitals. This workshop addresses primarily this first transition: radiopharmaceuticals, instrument performance characteristics, image processing, patient conditioning and positioning, interpretive strategies, and the definition of normal. At the time of the workshop, looking backward, it might appear the SPECT had not arrived at the time for interactions with other specialty societies; first, there must be evidence that techniques are repeatable; that they correlate with whatever gold standard is available; and that our patient-referring colleagues are willing to ask for them. However, looking forward, the questions of clinical utility, and the choices of {open_quotes}which technology{close_quotes} are here. It is time to prepare conceptually for the next step; how do we bring our new technologies to clinical acceptance, to reimbursement, and to an appropriate niche in the clinical firmament? The answer is via the pathways of practice guidelines.

  12. Evaluation of Mucociliary Clearance by Three Dimension Micro-CT-SPECT in Guinea Pig: Role of Bitter Taste Agonists

    PubMed Central

    Ortiz, Jose Luis; Ortiz, Amparo; Milara, Javier; Armengot, Miguel; Sanz, Celia; Compañ, Desamparados; Morcillo, Esteban; Cortijo, Julio

    2016-01-01

    Different image techniques have been used to analyze mucociliary clearance (MCC) in humans, but current small animal MCC analysis using in vivo imaging has not been well defined. Bitter taste receptor (T2R) agonists increase ciliary beat frequency (CBF) and cause bronchodilation but their effects in vivo are not well understood. This work analyzes in vivo nasal and bronchial MCC in guinea pig animals using three dimension (3D) micro-CT-SPECT images and evaluates the effect of T2R agonists. Intranasal macroaggreggates of albumin-Technetium 99 metastable (MAA-Tc99m) and lung nebulized Tc99m albumin nanocolloids were used to analyze the effect of T2R agonists on nasal and bronchial MCC respectively, using 3D micro-CT-SPECT in guinea pig. MAA-Tc99m showed a nasal mucociliary transport rate of 0.36 mm/min that was increased in presence of T2R agonist to 0.66 mm/min. Tc99m albumin nanocolloids were homogeneously distributed in the lung of guinea pig and cleared with time-dependence through the bronchi and trachea of guinea pig. T2R agonist increased bronchial MCC of Tc99m albumin nanocolloids. T2R agonists increased CBF in human nasal ciliated cells in vitro and induced bronchodilation in human bronchi ex vivo. In summary, T2R agonists increase MCC in vivo as assessed by 3D micro-CT-SPECT analysis. PMID:27723827

  13. Mirror-image lymph node in FDG PET/CT and SPECT/CT for sentinel node detection.

    PubMed

    Domenech, Beatriz; Paredes, Pilar; Rubí, Sebastià; Pahisa, Jaume; Vidal-Sicart, Sergi; Pons, Francesca

    2014-03-01

    We report a case of a patient with presumed stage IB1 squamous cell carcinoma of the cervix in which FDG PET/CT scan revealed 1 hypermetabolic left iliac node suggestive to be malignant. Lymphoscintigraphy and SPECT/CT studies previous to sentinel node (SLN) biopsy revealed unilateral drainage in the right pelvis. Intraoperative pathological assessment of the SLN showed no tumoral involvement, and the hypermetabolic node revealed macrometastasis. Tumor node invasion can lead to a lymphatic blockage and become false-negative for SLN technique. Although FDG PET/CT has lower sensitivity than surgical staging, this case shows its value as a preoperative imaging technique.

  14. reSpect: Software for Identification of High and Low Abundance Ion Species in Chimeric Tandem Mass Spectra

    PubMed Central

    Shteynberg, David; Mendoza, Luis; Hoopmann, Michael R.; Sun, Zhi; Schmidt, Frank; Deutsch, Eric W.; Moritz, Robert L.

    2016-01-01

    Most shotgun proteomics data analysis workflows are based on the assumption that each fragment ion spectrum is explained by a single species of peptide ion isolated by the mass spectrometer; however, in reality mass spectrometers often isolate more than one peptide ion within the window of isolation that contributes to additional peptide fragment peaks in many spectra. We present a new tool called reSpect, implemented in the Trans-Proteomic Pipeline (TPP), that enables an iterative workflow whereby fragment ion peaks explained by a peptide ion identified in one round of sequence searching or spectral library search are attenuated based on the confidence of the identification, and then the altered spectrum is subjected to further rounds of searching. The reSpect tool is not implemented as a search engine, but rather as a post search engine processing step where only fragment ion intensities are altered. This enables the application of any search engine combination in the following iterations. Thus, reSpect is compatible with all other protein sequence database search engines as well as peptide spectral library search engines that are supported by the TPP. We show that while some datasets are highly amenable to chimeric spectrum identification and lead to additional peptide identification boosts of over 30% with as many as four different peptide ions identified per spectrum, datasets with narrow precursor ion selection only benefit from such processing at the level of a few percent. We demonstrate a technique that facilitates the determination of the degree to which a dataset would benefit from chimeric spectrum analysis. The reSpect tool is free and open source, provided within the TPP and available at the TPP website. PMID:26419769

  15. reSpect: Software for Identification of High and Low Abundance Ion Species in Chimeric Tandem Mass Spectra

    NASA Astrophysics Data System (ADS)

    Shteynberg, David; Mendoza, Luis; Hoopmann, Michael R.; Sun, Zhi; Schmidt, Frank; Deutsch, Eric W.; Moritz, Robert L.

    2015-11-01

    Most shotgun proteomics data analysis workflows are based on the assumption that each fragment ion spectrum is explained by a single species of peptide ion isolated by the mass spectrometer; however, in reality mass spectrometers often isolate more than one peptide ion within the window of isolation that contribute to additional peptide fragment peaks in many spectra. We present a new tool called reSpect, implemented in the Trans-Proteomic Pipeline (TPP), which enables an iterative workflow whereby fragment ion peaks explained by a peptide ion identified in one round of sequence searching or spectral library search are attenuated based on the confidence of the identification, and then the altered spectrum is subjected to further rounds of searching. The reSpect tool is not implemented as a search engine, but rather as a post-search engine processing step where only fragment ion intensities are altered. This enables the application of any search engine combination in the iterations that follow. Thus, reSpect is compatible with all other protein sequence database search engines as well as peptide spectral library search engines that are supported by the TPP. We show that while some datasets are highly amenable to chimeric spectrum identification and lead to additional peptide identification boosts of over 30% with as many as four different peptide ions identified per spectrum, datasets with narrow precursor ion selection only benefit from such processing at the level of a few percent. We demonstrate a technique that facilitates the determination of the degree to which a dataset would benefit from chimeric spectrum analysis. The reSpect tool is free and open source, provided within the TPP and available at the TPP website.

  16. An SVD Investigation of Modeling Scatter in Multiple Energy Windows for Improved SPECT Images

    PubMed Central

    Kadrmas, Dan J.; Frey, Eric C.; Tsui, Benjamin M.W.

    2009-01-01

    In this work singular value decomposition (SVD) techniques are used to investigate how the use of low energy photons and multiple energy windows affects the noise properties of Tc-99m SPECT imaging. We have previously shown that, when modeling scatter in the projector and backprojector of iterative reconstruction algorithms, simultaneous reconstruction from multiple energy window data can result in very different noise characteristics. Further, the properties depend upon the width and number of energy windows used. To investigate this further, we have generated photon transport matrices using models for scatter, an elliptical phantom containing cold rods of various sizes, and a number of multiple energy window acquisition schemes. Transfer matrices were also generated for the cases of perfect scatter rejection and ideal scatter subtraction. The matrices were decomposed using SVD, and signal power and projection space variance spectra were computed using the basis formed by the left singular vectors. Results indicate very different noise levels for the various energy window combinations. The perfect scatter rejection case resulted in the lowest variance spectrum, and reconstruction-based scatter compensation performed better than the scatter subtraction case. When including lower energy photons in reconstruction-based scatter compensation, using a series of multiple energy windows outperformed a single large energy window. One multiple window combination is presented which achieves a lower variance spectrum than the standard 20% energy window, indicating the potential for using low energy photons to improve the noise characteristics of SPECT images. PMID:20186285

  17. Evaluation of hardware in a small-animal SPECT system using reconstructed images

    NASA Astrophysics Data System (ADS)

    Hesterman, Jacob Y.; Kupinski, Matthew A.; Clarkson, Eric; Wilson, Donald W.; Barrett, Harrison H.

    2007-03-01

    Evaluation of imaging hardware represents a vital component of system design. In small-animal SPECT imaging, this evaluation has become increasingly diffcult with the emergence of multi-pinhole apertures and adaptive, or patient-specific, imaging. This paper will describe two methods for hardware evaluation using reconstructed images. The first method is a rapid technique incorporating a system-specific non-linear, three-dimensional point response. This point response is easily computed and offers qualitative insight into an aperture's resolution and artifact characteristics. The second method is an objective assessment of signal detection in lumpy backgrounds using the channelized Hotelling observer (CHO) with 3D Laguerre-Gauss and difference-of-Gaussian channels to calculate area under the receiver-operating characteristic curve (AUC). Previous work presented at this meeting described a unique, small-animal SPECT system (M 3R) capable of operating under a myriad of hardware configurations and ideally suited for image quality studies. Measured system matrices were collected for several hardware configurations of M 3R. The data used to implement these two methods was then generated by taking simulated objects through the measured system matrices. The results of these two methods comprise a combination of qualitative and quantitative analysis that is well-suited for hardware assessment.

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

    PubMed

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

    2016-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

  20. Attenuation correction in SPECT images using attenuation map estimation with its emission data

    NASA Astrophysics Data System (ADS)

    Tavakoli, Meysam; Naji, Maryam; Abdollahi, Ali; Kalantari, Faraz

    2017-03-01

    Photon attenuation during SPECT imaging significantly degrades the diagnostic outcome and the quantitative accuracy of final reconstructed images. It is well known that attenuation correction can be done by using iterative reconstruction methods if we access to attenuation map. Two methods have been used to calculate the attenuation map: transmission-based and transmissionless techniques. In this phantom study, we evaluated the importance of attenuation correction by quantitative evaluation of errors associated with each method. For transmissionless approach, the attenuation map was estimated from the emission data only. An EM algorithm with attenuation model was developed and used for attenuation correction during image reconstruction. Finally, a comparison was done between reconstructed images using our OSEM code and analytical FBP method before and after attenuation correction. The results of measurements showed that: our programs are capable to reconstruct SPECT images and correct the attenuation effects. Moreover, to evaluate reconstructed image quality before and after attenuation correction we applied a novel approach using Image Quality Index. Attenuation correction increases the quality and quantitative accuracy in both methods. This increase is independent of activity in quantity factor and decreases with activity in quality factor. In EM algorithm, it is necessary to use regularization to obtain true distribution of attenuation coefficients.

  1. A non-rigid registration method for serial lower extremity hybrid SPECT/CT imaging

    PubMed Central

    Suh, Jung W.; Scheinost, Dustin; Dione, Donald P.; Dobrucki, Lawrence W.; Sinusas, Albert J.; Papademetris, Xenophon

    2010-01-01

    Small animal X-ray computed tomographic (microCT) imaging of the lower extremities permits evaluation of arterial growth in models of hindlimb ischemia, and when applied serially can provide quantitative information about disease progression and aid in the evaluation of therapeutic interventions. The quantification of changes in tissue perfusion and concentration of molecular markers concurrently obtained using nuclear imaging requires the ability to non-rigidly register the microCT images over time, a task made more challenging by the potentially large changes in the positions of the legs due to articulation. While non-rigid registration methods have been extensively used in the evaluation of individual organs, application in whole body imaging has been limited, primarily because the scale of possible displacements and deformations is large resulting in poor convergence of most methods. In this paper we present a new method based on the extended demons algorithm that uses a level-set representation of the body contour and skeletal structure as an input. The proposed serial registration method reflects the natural physical moving combination of mouse anatomy in which the movement of bones is the framework for body movements, and the movement of skin constrains the detailed movements of the specific segmented body regions. We applied our method to both the registration of serial microCT mouse images and the quantification of microSPECT component of the serially hybrid microCT-SPECT images demonstrating improved performance as compared to existing registration techniques. PMID:20869902

  2. Thallium-201 accumulation in cerebral candidiasis: Unexpected finding on SPECT

    SciTech Connect

    Tonami, N.; Matsuda, H.; Ooba, H.; Yokoyama, K.; Hisada, K.; Ikeda, K.; Yamashita, J. )

    1990-06-01

    The authors present an unexpected finding of Tl-201 uptake in the intracerebral lesions due to candidiasis. SPECT demonstrated the extent of the lesions and a high target-to-background ratio. The regions where abnormal Tl-201 accumulation was seen were nearly consistent with CT scans of those enhanced by a contrast agent. After treatment, most of the abnormal Tl-201 accumulation disappeared.

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

    SciTech Connect

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

    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 the 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.

  4. 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

  5. Nonlinear dual reconstruction of SPECT activity and attenuation images.

    PubMed

    Liu, Huafeng; Guo, Min; Hu, Zhenghui; Shi, Pengcheng; Hu, Hongjie

    2014-01-01

    In single photon emission computed tomography (SPECT), accurate attenuation maps are needed to perform essential attenuation compensation for high quality radioactivity estimation. Formulating the SPECT activity and attenuation reconstruction tasks as coupled signal estimation and system parameter identification problems, where the activity distribution and the attenuation parameter are treated as random variables with known prior statistics, we present a nonlinear dual reconstruction scheme based on the unscented Kalman filtering (UKF) principles. In this effort, the dynamic changes of the organ radioactivity distribution are described through state space evolution equations, while the photon-counting SPECT projection data are measured through the observation equations. Activity distribution is then estimated with sub-optimal fixed attenuation parameters, followed by attenuation map reconstruction given these activity estimates. Such coupled estimation processes are iteratively repeated as necessary until convergence. The results obtained from Monte Carlo simulated data, physical phantom, and real SPECT scans demonstrate the improved performance of the proposed method both from visual inspection of the images and a quantitative evaluation, compared to the widely used EM-ML algorithms. The dual estimation framework has the potential to be useful for estimating the attenuation map from emission data only and thus benefit the radioactivity reconstruction.

  6. The aSPECT experiment - an overview and latest results

    NASA Astrophysics Data System (ADS)

    Schmidt, Christian; Aspect Collaboration

    2016-09-01

    The aSPECT retardation spectrometer measures the β- ν angular correlation coefficient a in free neutron β-decay. This measurement can be used to determine the ratio gA/gV of the weak coupling constants, as well as to search for physics beyond the Standard Model. In 2013 aSPECT had a successful beam time at the Institut Laue-Langevin. The goal of this beam time is to improve the current uncertainty of a from Δa / a 5 % to about 1%. The data analysis is in its final stage and nearly finished. In order to achieve an uncertainty of 1%, the systematics of aSPECT have to be understood accordingly. This is achieved by systematic tests and measurements of a with different parameter settings for the spectrometer during the beam time. Additionally, offline measurements have been performed to determine the effect on the systematics, e.g. work-function fluctuations of the electrodes. These measurements are used as input for on-going simulations of the spectrometer to understand and reduce the systematic uncertainties further. In this talk aSPECT will be introduced and the current status of the data analysis will be reported, including a preliminary error budget of the systematic uncertainties.

  7. Small hepatocellular carcinomas in chronic liver disease: Detection with SPECT

    SciTech Connect

    Kudo, M.; Hirasa, M.; Takakuwa, H.; Ibuki, Y.; Fujimi, K.; Miyamura, M.; Tomita, S.; Komori, H.; Todo, A.; Kitaura, Y.

    1986-06-01

    Single-photon emission computed tomography (SPECT) performed using a rotating gamma camera was compared with ..cap alpha../sub 1/-fetoprotein (AFP) assay, conventional liver scintigraphy, ultrasound (US) imaging, computed tomography (CT), and selective celiac angiography in 40 patients with a total of 50 small hepatocellular carcinomas (HCCs;<5 cm). The detection rates of US and CT were determined on an initial screening study and on a second, more precisely focused study. The detection rate of small HCCs by the various modalities was as follows: AFP, 13%; liver scintigraphy, 36%; SPECT, 72%; initial screening US, 80%; second, more precise US studies, 94%; initial screening CT, 64%; second, more precise CT study, 82%; angiography, 88%. Although SPECT was inferior to the initial screening US examination in detecting HCCs less than 2 cm in size, its sensitivity was identical to that of the initial screening US study for detecting HCCs of 2-5 cm. The combination of SPECT and US was an excellent method for the early detection of HCCs, yielding a detection rate of 94%.

  8. Evaluation of SPECT quantification of radiopharmaceutical distribution in canine myocardium

    SciTech Connect

    Li, Jianying; Jaszczak, R.L.; Greer, K.L.

    1995-02-01

    This study evaluates the quantitative accuracy of SPECT for in vivo distributions of {sup 99m}Tc radiopharmaceuticals using fanbeam (FB) and parallel-beam (PB) collimators and compares uniform and nouniform attenuation correction methods in terms of quantitative accuracy. SPECT quantification of canine myocardial radioactivity was performed followed by well counter measurements of extracted myocardial tissue samples. Transmission scans using a line source and an FB collimator were performed to generate nonuniform attenuation maps of the canine thorax. Emission scans with two energy windows were acquired. Images were reconstructed using a filtered backprojection algorithm, with a dual-window scatter subtraction combined with either no attenuation compensation or single iteration Chang attenuation compensation based on a uniform attenuation map {mu}=0.152 cm{sup -1} or the nonuniform transmission map. The measured mean counts from the SPECT images were converted using the well counter. The experimental results demonstrate that, compared with well counter values, the in vivo distributions of {sup 99m}Tc were most accurately determined in FB and PB SPECT reconstructions with nonuniform attenuation compensation, under-estimated without attenuation compensation and overestimated with uniform attenuation compensation. 37 refs., 9 figs., 10 tabs.

  9. Thallium-201 SPECT increases detectability of thyroid cancer metastases

    SciTech Connect

    Charkes, N.D.; Vitti, R.A.; Brooks, K. )

    1990-02-01

    Thallium-201- ({sup 201}Tl) chloride is known to accumulate in metastatic foci of differentiated thyroid carcinoma, but small and deep-seated lesions are generally not detectable by planar imaging. We have evaluated the use of 201Tl-chloride single-photon emission computed tomography (SPECT) in 41 post-thyroidectomy patients with differentiated thyroid carcinoma and one with medullary carcinoma; planar imaging alone was done in eight additional patients (total 50). Of 20 patients with known metastatic disease, planar {sup 201}Tl images were positive in 12 (60%) but SPECT revealed an additional 5 (25%) who had metastases (total 85%). SPECT revealed foci as small as 1.0 cm in the neck and 1.5 cm in the lungs, and was particularly useful in detection of disseminated micronodular pulmonary metastases, especially in patients whose scans were negative with diagnostic doses of {sup 131}I. Some pitfalls in interpretation of the tomographic reconstructions were found. Thallium-201 SPECT is a marked improvement over planar imaging in the detection of metastases of differentiated thyroid cancer.

  10. CALOR87: HETC87, MICAP, EGS4, and SPECT

    SciTech Connect

    Gabriel, T.A.; Alsmiller, F.S.; Alsmiller, R.G. Jr.; Bishop, B.L.; Hermann, O.W.; Johnson, J.O.

    1987-01-01

    A brief history of CALOR (HETC, EGS, MICAP, SPECT) is presented to indicate the evolution of this code system. Details concerning the current modifications and additions to the high-energy transport code, HETC, are also presented and new comparisons with experimental data are included to verify the new physics improvements. 27 refs., 5 figs.

  11. Nonlinear Dual Reconstruction of SPECT Activity and Attenuation Images

    PubMed Central

    Liu, Huafeng; Guo, Min; Hu, Zhenghui; Shi, Pengcheng; Hu, Hongjie

    2014-01-01

    In single photon emission computed tomography (SPECT), accurate attenuation maps are needed to perform essential attenuation compensation for high quality radioactivity estimation. Formulating the SPECT activity and attenuation reconstruction tasks as coupled signal estimation and system parameter identification problems, where the activity distribution and the attenuation parameter are treated as random variables with known prior statistics, we present a nonlinear dual reconstruction scheme based on the unscented Kalman filtering (UKF) principles. In this effort, the dynamic changes of the organ radioactivity distribution are described through state space evolution equations, while the photon-counting SPECT projection data are measured through the observation equations. Activity distribution is then estimated with sub-optimal fixed attenuation parameters, followed by attenuation map reconstruction given these activity estimates. Such coupled estimation processes are iteratively repeated as necessary until convergence. The results obtained from Monte Carlo simulated data, physical phantom, and real SPECT scans demonstrate the improved performance of the proposed method both from visual inspection of the images and a quantitative evaluation, compared to the widely used EM-ML algorithms. The dual estimation framework has the potential to be useful for estimating the attenuation map from emission data only and thus benefit the radioactivity reconstruction. PMID:25225796

  12. Geometric characterization of multi-axis multi-pinhole SPECT

    SciTech Connect

    DiFilippo, Frank P.

    2008-01-15

    A geometric model and calibration process are developed for single photon emission computed tomography (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 deg. 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 deg. 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.

  13. Three-dimensional presentation of the Fourier amplitude and phase: a fast display method for gated cardiac blood-pool SPECT.

    PubMed

    Máté, E; Mester, J; Csernay, L; Kuba, A; Madani, S; Makay, A

    1992-03-01

    The routine clinical use of gated SPECT is inhibited by sophisticated, time-consuming processing techniques. The present paper describes a new technique for the simultaneous three-dimensional presentation of the amplitude and phase of the first Fourier harmonics, with the aim of obtaining detailed information about the ventricular motion in a relatively short time, from each angle of view of three-dimensional space. The method is simple and robust, and processing is automatic. It does not need carefully elaborated techniques for surface determination, because the cardiac surface is merely used as a reference skeleton onto which the functional information of amplitude and phase is mapped. The Fourier analysis before reconstruction results in running times shorter than 15 min and may further open the way for the routine use of gated SPECT.

  14. [Variables that influence the indication of a second myocardial perfusion gated-SPECT after a normal stress-rest gated SPECT].

    PubMed

    Romero-Farina, G; Candell-Riera, J; Aguadé-Bruix, S; Cuberas-Borrós, G; Pizzi, M N; Santos, A; de León, G; García-Dorado, D

    2014-01-01

    The objective of this study was to investigate predictor variables at the moment of normal stress-rest myocardial perfusion gated SPECT for indication of a second gated SPECT. A prospective, single center cohort study was conducted. We evaluated 2326 consecutive patients (age 63.6 ± 13 years, 57.3% females) without perfusion defects and with normal left ventricular ejection fraction on a myocardial perfusion gated SPECT. Clinical and stress test variables were studied to predict indication of a second gated SPECT and presence of reversible perfusion defects in the second gated SPECT. During a mean follow-up of 3.6 ± 2 years a second gated SPECT was performed in 286 patients (12.3%). Independent predictor variables of a second gated SPECT were presence of three or more cardiovascular risk factors (χ(2): 5.510; HR: 1.4; p=0.019), previous acute myocardial infarction (χ(2): 3.867; HR: 1.4; p=0.049), previous coronary revascularization (χ(2): 41.081; HR: 2.5; p<0.001), and a positive stress test (χ(2): 8.713; HR: 1.5; p=0.003). Observation of perfusion defects in the 280 patients in whom a second stress-rest gated SPECT was performed was more likely in male patients (χ(2): 4.322; HR: 1.9; p=0.038) who had a first pure pharmacological gated-SPECT (χ(2): 7.182; HR: 2.6; p=0.007). In patients with a first normal myocardial perfusion gated SPECT, various clinical factors and variables derived from the stress test affect the indication of a second gated SPECT and the presence of ischemia in the latter. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

  15. Detection rate of (99m) Tc-MIBI single photon emission computed tomography (SPECT)/CT in preoperative planning for patients with primary hyperparathyroidism: A meta-analysis.

    PubMed

    Treglia, Giorgio; Sadeghi, Ramin; Schalin-Jäntti, Camilla; Caldarella, Carmelo; Ceriani, Luca; Giovanella, Luca; Eisele, David W

    2016-04-01

    Parathyroid scintigraphy using (99m) Tc-MIBI single photon emission computed tomography (SPECT)/CT has been proposed as one of the most accurate localization techniques in patients with primary hyperparathyroidism (PHPT). The purpose of this review was to meta-analyze published data on the detection rate of (99m) Tc-MIBI SPECT/CT in the preoperative planning of patients with PHPT. A comprehensive literature search of studies published through June 2014 was performed. The pooled detection rate of this scintigraphic method including 95% confidence intervals (95% CIs) was calculated on a per patient-based and on a per lesion-based analysis by using a random effects model. Twenty-three articles including 1236 patients with PHPT were selected. The pooled detection rate of (99m) Tc-MIBI SPECT/CT in the preoperative planning of patients with PHPT was 88% (95% CI = 84% to 92%) and 88% (95% CI = 82% to 92%) on a per patient-based and per lesion-based analysis, respectively. The (99m) Tc-MIBI SPECT/CT has high detection rate for hyperfunctioning parathyroid glands in patients with PHPT. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2159-E2172, 2016. © 2015 Wiley Periodicals, Inc.

  16. Collimator design for a multipinhole brain SPECT insert for MRI.

    PubMed

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

    2015-11-01

    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 can operate inside a clinical MRI. 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. The optimization resulted in a stationary multipinhole system with a collimator radius of 150.2 mm and a detector radius of 172.67 mm, which corresponds to four rings of 34 diSPM detector modules. This allows the authors to include eight rings of 24 pinholes, which results in a system volume sensitivity of 395 cps/MBq. Noiseless simulations show sufficient axial

  17. Collimator design for a multipinhole brain SPECT insert for MRI

    SciTech Connect

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

    2015-11-15

    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 can operate inside a clinical MRI. Methods: The authors designed and simulated a compact stationary multipinhole SPECT insert based on digital silicon photomultiplier detector modules, which have shown to be MR-compatible and have an excellent intrinsic resolution (0.5 mm) when combined with a monolithic 2 mm thick LYSO crystal. First, the authors optimized the different parameters of the SPECT system to maximize sensitivity for a given target resolution of 7.2 mm in the center of the field-of-view, given the spatial constraints of the MR system. Second, the authors performed noiseless simulations of two multipinhole configurations to evaluate sampling and reconstructed resolution. Finally, the authors performed Monte Carlo simulations and compared the SPECT insert with a clinical system with ultrahigh-resolution (UHR) fan beam collimators, based on contrast-to-noise ratio and a visual comparison of a Hoffman phantom with a 9 mm cold lesion. Results: The optimization resulted in a stationary multipinhole system with a collimator radius of 150.2 mm and a detector radius of 172.67 mm, which corresponds to four rings of 34 diSPM detector modules. This allows the authors to include eight rings of 24 pinholes, which results in a system volume sensitivity of 395 cps/MBq. Noiseless simulations

  18. 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.

  19. Advanced reconstruction of attenuation maps using SPECT emission data only

    NASA Astrophysics Data System (ADS)

    Salomon, André; Goedicke, Andreas; Aach, Til

    2009-02-01

    Today, attenuation corrected SPECT, typically performed using CT or Gadolinium line source based transmission scans, is more and more becoming standard in many medical applications. Moreover, the information about the material density distribution provided by these scans is key for other artifact compensation approaches in advanced SPECT reconstruction. Major drawbacks of these approaches are the additional patient radiation and hardware/maintenance costs as well as the additional workflow effort, e.g. if the CT scans are not performed on a hybrid scanner. It has been investigated in the past, whether it is possible to recover this structural information solely from the SPECT scan data. However, the investigated methods often result in noticeable image artifacts due to cross-dependences between attenuation and activity distribution estimation. With the simultaneous reconstruction method presented in this paper, we aim to effectively prevent these typical cross-talk artifacts using a-priori known atlas information of a human body. At first, an initial 3D shape model is coarsely registered to the SPECT data using anatomical landmarks and each organ structure within the model is identified with its typical attenuation coefficient. During the iterative reconstruction based on a modified ML-EM scheme, the algorithm simultaneously adapts both, the local activity estimation and the 3D shape model in order to improve the overall consistency between measured and estimated sinogram data. By explicitly avoiding topology modifications resulting in a non-anatomical state, we ensure that the estimated attenuation map remains realistic. Several tests with simulated as well as real patient SPECT data were performed to test the proposed algorithm, which demonstrated reliable convergence behaviour in both cases. Comparing the achieved results with available reference data, an overall good agreement for both cold as well as hot activity regions could be observed (mean deviation: -5.98%).

  20. [Cost-effectiveness of stress-only myocardial perfusion single photon emission computed tomography (SPECT) imaging].

    PubMed

    Vallejo, Enrique; Acevedo, César; Varela, Samuel; Alburez, José Carlos; Bialostozky, David

    2012-01-01

    Single photon emission computed tomography (SPECT) myocardial perfusion imaging is widely used for diagnosing coronary artery disease (CAD). However, SPECT costs, imaging time, and radiation exposure, limit SPECT indications. Determine whether a stress-only SPECT imaging would be enough to obtain a diagnosis of CAD improving nuclear laboratory efficiency. 122 patients with unknown CAD were evaluated with stress-only SPECT imaging. In order to evaluate diagnostic accuracy and the prognostic value of the stress-only protocol, patients with abnormal SPECT underwent invasive angiography and patients with normal SPECT were followed-up during 3 years. Diagnosis time, SPECT cost, and radiopharmaceutical dosage were significantly lower as compared with the conventional SPECT imaging protocol (30, 40 and 55%, respectively). Diagnostic accuracy and cardiac prognosis information were comparable to those obtained with the conventional imaging protocol (positive predictive value for CAD of 85% and negative predictive value for cardiac events of 97%). In patients with intermediate risk for CAD, stress-only SPECT imaging will significantly improve nuclear laboratory efficiency, and with similar accuracy than that the one obtained with the conventional protocol.

  1. Can hybrid SPECT-CT overcome the limitations associated with poor imaging properties of 131I-MIBG?: Comparison with planar scintigraphy and SPECT in pheochromocytoma.

    PubMed

    Sharma, Punit; Dhull, Varun Singh; Jeph, Sunil; Reddy, Rama Mohan; Singh, Harmandeep; Naswa, Niraj; Bal, Chandrasekhar; Kumar, Rakesh

    2013-09-01

    This study aimed to evaluate the incremental value of (131)I-MIBG hybrid SPECT-CT over planar scintigraphy (PS) and SPECT alone in patients with clinical or biochemical suspicion of pheochromocytoma. A total of 126 adrenals of 63 patients (mean [SD] age, 28.6 [15.7] years; male patients, n = 34; female patients, n = 29) with clinical or biochemical suspicion of pheochromocytoma were retrospectively evaluated. All patients had undergone (131)I-MIBG SPECT-CT of adrenal region. The PS, SPECT, and SPECT-CT images were independently evaluated by 2 nuclear medicine physicians with 6 years (R1) and 2 years (R2) experience and in separate sessions 1 week apart. A scoring scale of 1 to 5 was used, in which 1 is definitely abnormal, 2 is probably abnormal, 3 is indeterminate, 4 is probably normal, and 5 is definitely normal. Sensitivity, specificity, predictive values were calculated taking a score 2 or less as abnormal. With receiver operating characteristic (ROC) curve analysis, areas under the curve (AUC) were calculated for each modality and compared. Histopathology and/or clinical/imaging follow-up were taken as reference standard. Of the 126 adrenals evaluated, 29 were indeterminate on PS for R1 and 48 for R2, 39 were indeterminate on SPECT for both, and on SPECT-CT, 1 was indeterminate for R1 and 2 for R2. SPECT-CT correctly characterized 28 of 29 indeterminate adrenals on PS and 37 of 39 indeterminate adrenals on SPECT for R1. Similarly, for R2, SPECT-CT correctly characterized 45 of 48 indeterminate adrenals on PS and 33 of 39 indeterminate adrenals on SPECT. On ROC comparison, PS was inferior to SPECT (P = 0.040 for R1; P < 0.001 for R2) and SPECT-CT (P = 0.001 for R1; P < 0.001 for R2) for both the observers. Moreover, SPECT was inferior to SPECT-CT for both the observers (P = 0.017 for R1 and P = 0.001 for R2). Accuracy of SPECT-CT (R1, 97.6%; R2, 97.6%) was higher than PS (R1, 91.2%; R2, 84.1%) and SPECT (R1, 94.4%; R2, 86.5%). Interobserver agreement was

  2. Comparison of planar and SPECT thallium imaging in men and women

    SciTech Connect

    Links, J.M.; Fintel, D.F.; Becker, L.C.; Wagner, H.N. Jr.

    1985-05-01

    The authors studied the overall accuracy of planar and SPECT Tl imaging in the diagnosis of coronary artery disease (CAD) in 85 subjects (65 males, 20 females; 52 with angiographic CAD, 33 without CAD), and then separately analyzed men and women to see if factors such as breast attenuation significantly alter the accuracy. All subjects were exercised to symptom-limit or peak heart rate achievement, and injected with 2 mCi Tl-201. Planar and SPECT stress studies were acquired in a random order, with delayed studies acquired 3 hours after injection. The studies were viewed in a blinded, random order, and interpreted on a 5 point scale by consensus of 3 observers (1: definitely normal, 2: probably normal, 3: equivocal, 4: probably abnormal, 5: definitely abnormal). Receiver operating characteristic (ROC) curves were constructed for overall planar and SPECT, and then separately for male planar, male SPECT, female planar, female SPECT. The overall SPECT curve was above the overall planar curve. The overall SPECT curve was above the overall planar curve. At a specificity of 90%, SPECT sensitivity was 93%, planar was 80%. For both males and females, the SPECT curves were above the planar curves. However, both planar and SPECT male curves were above both female curves. At a specificity of 90%, sensitivities were male planar, 83%; male SPECT, 97%; female planar, 50%; female SPECT, 80%. This difference in accuracy between males and females was not due to adequacy of exercise (peak exercise heart rate in CAD pts: males, 145 +- 28 bpm; females, 151 +- 28; p=NS; in normals: 178 bpm for both males and females). SPECT is more accurate than planar imaging in the diagnosis of CAD. However, differences in accuracy exist between men and women, which may be due to breast attenuation.

  3. Validation of a short-scan-time imaging protocol for thallium-201 myocardial SPECT with a multifocal collimator.

    PubMed

    Horiguchi, Yoriko; Ueda, Tomohiro; Shiomori, Tomofumi; Kanna, Masahiko; Matsushita, Hirooki; Kawaminami, Tomoko; Sudo, Yuta; Kikuchi, Shinnosuke; Sasaki, Ryo; Hoshimiya, Jun; Morita, Yukiko

    2014-10-01

    IQ-SPECT (Siemens AG, Munich, Germany) is a highly sensitive single-photon-emission computed tomography (SPECT) myocardial perfusion imaging (MPI) system that uses a multifocal collimator. We searched for a suitable protocol for short-time imaging by IQ-SPECT in thallium-201 (Tl-201) MPI by evaluating phantom images and also by comparing human IQ-SPECT images with conventional SPECT images as reference standards. We assessed the image quality using the normalized mean square error (NMSE) and drew up count profiles in Tl-201 SPECT images acquired with IQ-SPECT in a phantom study. We also performed Tl-201 stress myocardial SPECT/CT in 21 patients and compared delayed images acquired by using IQ-SPECT with 36 or 17 views per head with images obtained by using conventional SPECT. The NMSE of SPECT images from IQ-SPECT with 36 views was approximately one-fifth of that with 17 views. The myocardial count profile of images with 17 views was lower than those of images with 36 or 104 views in some regions. Defect scores were significantly lower, and image quality scores higher, in images from conventional SPECT than in those from IQ-SPECT with 17 views. Defect scores and image quality scores were equivalent in images from conventional SPECT and those from IQ-SPECT with 36 views. Agreement with the results of conventional SPECT in terms of coronary artery territory-based defect judgment was the best in IQ-SPECT with 36 views with computed tomography-derived attenuation correction (CTAC): the kappa values for IQ-SPECT with 36 views were 0.76 (without CTAC) and 0.83 (with CTAC), and those for IQ-SPECT with 17 views were 0.62 (without CTAC) and 0.59 (with CTAC). The difference in quantitative tracer uptake between conventional SPECT images and IQ-SPECT images was significantly greater for IQ-SPECT images with 17 views than for those with 36 views. Scanning with 36 views per head with CTAC may be appropriate for Tl-201 MPI using IQ-SPECT, because it provides images equivalent to

  4. Discrepancies in brain perfusion SPECT findings between Tc-99m HMPAO and Tc-99m ECD: evaluation using dynamic SPECT in patients with hyperemia.

    PubMed

    Miyazawa, N; Koizumi, K; Mitsuka, S; Nukui, H

    1998-10-01

    Discrepancies have been reported between the findings of Tc-99m HMPAO and Tc-99m ECD brain perfusion SPECT imaging. This study investigated the discrepancies in the accumulation of these tracers using dynamic SPECT to detect the super early phase of distribution. Thirteen patients with luxury perfusion or high flow states were studied with both dynamic and standard SPECT using Tc-99m HMPAO and Tc-99m ECD within 1-3 days. Standard SPECT showed discrepancies in 6 of 13 patients. Patients with meningioma and cerebral thrombosis had increased accumulation of Tc-99m HMPAO and decreased uptake of Tc-99m ECD. Patients with arteriovenous malformation, subarachnoid hemorrhage, and cavernous angioma had decreased accumulation of both tracers, but to different degrees. Dynamic SPECT showed increased or normal accumulation (i.e., essentially no discrepancy) in the first few minutes. However, Tc-99m HMPAO had a longer retention time than Tc-99m ECD in the ensuing 5-10 minutes. Dynamic SPECT revealed a similar accumulation pattern but different washout rates for the two tracers. Tc-99m HMPAO might be a more suitable tracer to detect high flow states or luxury perfusion because the findings on standard SPECT were more in agreement with those of dynamic SPECT using this tracer.

  5. 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.

  6. 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

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

    PubMed

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

    2003-12-21

    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

  8. Improving quantitative dosimetry in (177)Lu-DOTATATE SPECT by energy window-based scatter corrections.

    PubMed

    de Nijs, Robin; Lagerburg, Vera; Klausen, Thomas L; Holm, Søren

    2014-05-01

    Patient-specific dosimetry of lutetium-177 ((177)Lu)-DOTATATE treatment in neuroendocrine tumours is important, because uptake differs across patients. Single photon emission computer tomography (SPECT)-based dosimetry requires a conversion factor between the obtained counts and the activity, which depends on the collimator type, the utilized energy windows and the applied scatter correction techniques. In this study, energy window subtraction-based scatter correction methods are compared experimentally and quantitatively. (177)Lu SPECT images of a phantom with known activity concentration ratio between the uniform background and filled hollow spheres were acquired for three different collimators: low-energy high resolution (LEHR), low-energy general purpose (LEGP) and medium-energy general purpose (MEGP). Counts were collected in several energy windows, and scatter correction was performed by applying different methods such as effective scatter source estimation (ESSE), triple-energy and dual-energy window, double-photopeak window and downscatter correction. The intensity ratio between the spheres and the background was measured and corrected for the partial volume effect and used to compare the performance of the methods. Low-energy collimators combined with 208 keV energy windows give rise to artefacts. For the 113 keV energy window, large differences were observed in the ratios for the spheres. For MEGP collimators with the ESSE correction technique, the measured ratio was close to the real ratio, and the differences between spheres were small. For quantitative (177)Lu imaging MEGP collimators are advised. Both energy peaks can be utilized when the ESSE correction technique is applied. The difference between the calculated and the real ratio is less than 10% for both energy windows.

  9. 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.

  10. Improving quantitative dosimetry in 177Lu-DOTATATE SPECT by energy window-based scatter corrections

    PubMed Central

    Lagerburg, Vera; Klausen, Thomas L.; Holm, Søren

    2014-01-01

    Purpose Patient-specific dosimetry of lutetium-177 (177Lu)-DOTATATE treatment in neuroendocrine tumours is important, because uptake differs across patients. Single photon emission computer tomography (SPECT)-based dosimetry requires a conversion factor between the obtained counts and the activity, which depends on the collimator type, the utilized energy windows and the applied scatter correction techniques. In this study, energy window subtraction-based scatter correction methods are compared experimentally and quantitatively. Materials and methods 177Lu SPECT images of a phantom with known activity concentration ratio between the uniform background and filled hollow spheres were acquired for three different collimators: low-energy high resolution (LEHR), low-energy general purpose (LEGP) and medium-energy general purpose (MEGP). Counts were collected in several energy windows, and scatter correction was performed by applying different methods such as effective scatter source estimation (ESSE), triple-energy and dual-energy window, double-photopeak window and downscatter correction. The intensity ratio between the spheres and the background was measured and corrected for the partial volume effect and used to compare the performance of the methods. Results Low-energy collimators combined with 208 keV energy windows give rise to artefacts. For the 113 keV energy window, large differences were observed in the ratios for the spheres. For MEGP collimators with the ESSE correction technique, the measured ratio was close to the real ratio, and the differences between spheres were small. Conclusion For quantitative 177Lu imaging MEGP collimators are advised. Both energy peaks can be utilized when the ESSE correction technique is applied. The difference between the calculated and the real ratio is less than 10% for both energy windows. PMID:24525900

  11. Clinical Role of Subtraction Ictal SPECT Coregistered to MR Imaging and (18)F-FDG PET in Pediatric Epilepsy.

    PubMed

    Perissinotti, Andrés; Setoain, Xavier; Aparicio, Javier; Rubí, Sebastiá; Fuster, Berta Marti; Donaire, Antonio; Carreño, Mar; Bargalló, Nuria; Rumiá, Jordi; Garcia-Fructuoso, Gemma; Mayoral, Maria; Sanmartí, Francesc; Pons, Francesca

    2014-07-01

    A precise assessment of the drug-resistant epileptic pediatric population for surgical candidacy is often challenging, and to date there are no evidence-based guidelines for presurgical identification of the epileptogenic zone. To evaluate the usefulness of radionuclide imaging techniques for presurgical evaluation of epileptic pediatric patients, we compared the results of video-electroencephalography (EEG), brain MR imaging, interictal SPECT, ictal SPECT, subtraction ictal SPECT coregistered to MR imaging (SISCOM), and interictal PET with (18)F-FDG. Fifty-four children with drug-resistant epilepsy who had undergone video-EEG monitoring, brain MR imaging, interictal and ictal brain perfusion SPECT, SISCOM, and (18)F-FDG PET were included in this study. All abnormal findings revealed by these neuroimaging techniques were compared with the presumed location of the epileptogenic zone (PEZ) as determined by video-EEG and clinical data. The proportion of localizing studies for each technique was statistically compared. In the 18 patients who underwent resective brain surgery, neuroimaging results were compared with histopathology results and surgical outcome. SISCOM and (18)F-FDG PET concordance with the PEZ was significantly higher than MR imaging (P < 0.05). MR imaging showed localizing results in 21 of 54 cases (39%), SISCOM in 36 of 54 cases (67%), and (18)F-FDG PET in 31 of 54 cases (57%). If we consider SISCOM and (18)F-FDG PET results together, nuclear medicine imaging techniques showed coinciding video-EEG results in 76% of patients (41/54). In those cases in which MR imaging failed to identify any epileptogenic lesion (61% [33/54]), SISCOM or (18)F-FDG PET findings matched PEZ in 67% (22/33) of cases. SISCOM and (18)F-FDG PET provide complementary presurgical information that matched video-EEG results and clinical data in three fourths of our sample. SISCOM was particularly useful in those cases in which MR imaging findings were abnormal but no epileptogenic

  12. Can brain thallium 201 SPECT substitute for F-18-FDG PET in detecting recurrent brain tumor in the presence of radiation necrosis; correlation with biopsy/surgery results

    SciTech Connect

    Antar, M.A.; Barnett, G.H.; McIntyre, W.J.

    1994-05-01

    F-18-FDG PET man has been largely successful in differentiating between radiation necrosis and recurrent brain tumors. Because of the expense and unavailability of PET scanners in most clinical centers, Tl-201 SPECT scan may offer an alternative. Therefore, we have evaluated both techniques in 18 patients (13 men and 5 women) whose ages range from 28 to 74 year old. Eleven patients had glioblastoma multiformi and 4 patients high grade astrocytoma and 3 patient meningiosarcoma. All patients received radiation therapy (5500-6000 Rad) and 13 patients received also chemotherapy. PET scan was performed 40-60 min. after 5-10 mCi of F-18 FDG (i.v.) and SPECT 30 min. after 4.6 mCi of Tl-201 chloride (i.v.). Severe FDG hypometabolism was evident in the irradiated regions, in all patients. Evidence of tumor recurrence was seen in 15 patients by both FDG PET and Thallium 201 SPECT. The ratio of peak pixel uptake of suspected tumor to that of normal cortex for FDG ranged from 0.67 to 1.5 with a mean of 1.02. The ratio of peak pixel uptake of thallium 201 in the suspected lesion to that of the contralateral scalp area ranges from 0.8 to 1.9 with mean of 1.1. There was concordance between the findings of PET and SPECT in 16/18 patients. However, the volume of involvement differs in these patients; most likely secondary to different mechanisms of uptake and both studies may complement each other. Subsequent biopsy/surgery in 11 patients confirmed tumor recurrence in 10 out of 11 patients. The findings suggest that thallium 201 brain SPECT scan can provide similar (but not identical) information regarding brain tumor recurrence in these patients.

  13. Three-minute SPECT/CT is sufficient for the assessment of bone metastasis as add-on to planar bone scintigraphy: prospective head-to-head comparison to 11-min SPECT/CT.

    PubMed

    Zacho, Helle D; Manresa, José A Biurrun; Aleksyniene, Ramune; Ejlersen, June A; Fledelius, Joan; Bertelsen, Henrik; Petersen, Lars J

    2017-12-01

    The aim of this study is to assess whether ultra-fast acquisition SPECT/CT (UF-SPECT/CT) can replace standard SPECT/CT (std-SPECT/CT) as "add-on" to whole-body bone scintigraphy (WB-BS) for the investigation of bone metastases. Consecutive cancer patients referred for WB-BS who underwent SPECT/CT in addition to WB-BS were included. Std-SPECT, UF-SPECT, and low-dose CT were performed (std-SPECT: matrix 128 × 128, zoom factor 1, 20 s/view, 32 views; UF-SPECT: identical parameters except for 10 s/view and 16 views, reducing the acquisition time from 11 to 3 min). A consensus diagnosis was reached by two observers for each set of images (WB-BS + standard SPECT/CT or WB-BS + UF-SPECT/CT) using a three-category evaluation scale: M0: no bone metastases; M1: bone metastases; and Me: equivocal findings. Among the 104 included patients, most presented with prostate cancer (n = 71) or breast cancer (n = 28). Using WB-BS + std-SPECT/CT, 71 (68%) patients were classified as M0, 19 (18%) as M1, and 14 (14%) as Me. Excellent agreement was observed between WB-BS + std-SPECT/CT and WB-BS + UF-SPECT/CT using the three-category scale: kappa = 0.91 (95% CI 0.84-0.97). No difference in observer agreement between cancer types was detected. SPECT/CT provided a definitive classification in 90 of 104 cases in which WB-BS was not entirely diagnostic. To investigate potential bone metastases, UF-SPECT/CT can be conducted as add-on to WB-BS to notably reduce the SPECT acquisition time without compromising diagnostic confidence.

  14. Diagnosis of myocardial involvement in patients with systemic myopathies with 15-(p-(I-123)iodophenyl) pentadecanoic acid (IPPA) SPECT

    SciTech Connect

    Kropp, J.; Briele, B.; Smekal, A.V.; Hotze, A.L.; Biersack, H.J.; Koehler, U.; Zierz, St. ); Knapp, F.F. )

    1992-01-01

    Involvement of the myocardium in non-infectious myopathies presents in most cases as systolic dysfunction or a disturbed cardiac rhythm. We are interested in exploring how often cardiac involvement can be evaluated with various diagnostic techniques in patients with proven myopathy. We investigated 41 patients with myopathies of various etiology, including mitochondrial and congenital myopathies, Curshmann-Steinert disease, muscular dystrophy, and others. Myopathy was proven by muscular biopsy usually from the bicep. Fatty acid imaging was performed with 15-(p-(I-123)iodophenyl)pentadecanoic acid (IP-PA) and sequential SPECT-scintigraphy with a 180 deg. rotation starting at the 45 deg. RAO position. 190 MBq were injected at the maximal stage of a submaximal exercise. Filtered backprojection and reorientation of the slices were achieved by standard techniques. The quantitative comparison of the oblique slices (bulls-eye technique) of the SPECT-studies revealed turnover-rates as a qualitative measure of {beta}-oxidation. Serum levels of lactate (L), pyruvate (P), glucose (G) and triglycerides (TG) were measured at rest and stress. Ventricular function was investigated by radionuclide ventriculography (MUGA) at rest and under stress with Tc-99m labeled red blood cells. In addition, ECG, 24 hour-ECG, and echocardiography were also performed with standard techniques.

  15. Diagnosis of myocardial involvement in patients with systemic myopathies with 15-(p-[I-123]iodophenyl) pentadecanoic acid (IPPA) SPECT

    SciTech Connect

    Kropp, J.; Briele, B.; Smekal, A.V.; Hotze, A.L.; Biersack, H.J.; Koehler, U.; Zierz, St.; Knapp, F.F.

    1992-03-01

    Involvement of the myocardium in non-infectious myopathies presents in most cases as systolic dysfunction or a disturbed cardiac rhythm. We are interested in exploring how often cardiac involvement can be evaluated with various diagnostic techniques in patients with proven myopathy. We investigated 41 patients with myopathies of various etiology, including mitochondrial and congenital myopathies, Curshmann-Steinert disease, muscular dystrophy, and others. Myopathy was proven by muscular biopsy usually from the bicep. Fatty acid imaging was performed with 15-(p-[I-123]iodophenyl)pentadecanoic acid (IP-PA) and sequential SPECT-scintigraphy with a 180 deg. rotation starting at the 45 deg. RAO position. 190 MBq were injected at the maximal stage of a submaximal exercise. Filtered backprojection and reorientation of the slices were achieved by standard techniques. The quantitative comparison of the oblique slices (bulls-eye technique) of the SPECT-studies revealed turnover-rates as a qualitative measure of {beta}-oxidation. Serum levels of lactate (L), pyruvate (P), glucose (G) and triglycerides (TG) were measured at rest and stress. Ventricular function was investigated by radionuclide ventriculography (MUGA) at rest and under stress with Tc-99m labeled red blood cells. In addition, ECG, 24 hour-ECG, and echocardiography were also performed with standard techniques.

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

    PubMed

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

    2015-11-01

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

  17. [New trends and novel possibilities in the clinical use of SPECT/CT imaging].

    PubMed

    Zámbó, Katalin; Schmidt, Erzsébet; Szabó, Zsuzsanna; Sarkadi, Margit; Dérczy, Katalin; Szekeres, Sarolta

    2015-03-01

    The application of hybrid equipments and fused techniques has increasing importance in the field of imaging diagnostics. The biggest advantage of these methods is the simultaneous use of several modalities which can give data about the morphological, functional as well as molecular changes of the different diseases at the same time. The facilities, advantages and the applicability of the SPECT/CT (single photon emission computer tomograph/computer tomograph) are summarized in this paper mainly in oncologic diseases, but also in other disorders. The multimodality equipments showing the function and morphology together increase the specificity and diagnostic accuracy of the nuclear medicine methods and were found to be more efficient in the therapy effectiveness, too.

  18. Intrathoracic stomach mimicking bone metastasis from thyroid cancer in whole-body iodine-131 scan diagnosed by SPECT/CT.

    PubMed

    García-Gómez, Francisco Javier; la Riva-Pérez, Pablo Antonio de; Calvo-Morón, Cinta; Buján-Lloret, Cristina; Cambil-Molina, Teresa; Castro-Montaño, Juan

    2017-01-01

    The whole-body iodine-131 scintigraphy is an imaging technique in monitoring patients with a history of thyroid cancer. Although the rate of false positives is negligible, it is not nonexistent. We report the case of an intervened and treated patient for thyroid cancer with good clinical and biochemical response. Scintigraphic findings were consistent with unsuspected bone metastasis. Fused SPECT/CT data allowed accurate diagnosis of giant diaphragmatic hernia associated with intrathoracic stomach, a very rare pathology that can lead to false positive results.

  19. Potential value of serial cerebral SPECT scanning in the evaluation of psychiatric illness

    SciTech Connect

    Notardonato, H.; Gonzalez-Avilez, A.; Van Heertum, R.L.; O'Connell, R.A.; Yudd, A.P.

    1989-05-01

    Cerebral SPECT imaging has the potential to make an important contribution to clinical psychiatry. Cerebral SPECT scanning, stimulated by the work with PET, is readily available and much less expensive than PET. This paper reports a case demonstrating the potential value of cerebral SPECT scanning with I-123 IMP, specifically in the serial evaluation of a schizophrenic patient with auditory hallucinations. The initial scan revealed focal areas of increased uptake in the caudate nuclei of the basal ganglia, and in the right temporal lobe. After pharmacological treatment with clinical improvement, the follow-up SPECT scan demonstrated significant improvement in the distribution of the radiopharmaceutical.

  20. Evaluation of the use of freehand SPECT for sentinel node biopsy in early stage oral carcinoma.

    PubMed

    Heuveling, Derrek A; van Weert, Stijn; Karagozoglu, K Hakki; de Bree, Remco

    2015-03-01

    Inadequate intraoperative visualization of the sentinel node can hamper its harvest. Freehand SPECT is a 3D tomographic imaging modality based on the concepts of SPECT, which can be used for intraoperative visualization and navigation towards the sentinel node in order to improve its localization and removal during surgery. The use of freehand SPECT was evaluated during 66 sentinel node biopsy procedures in early stage oral cancer patients. Intraoperative detection of sentinel nodes was compared with preoperative identified sentinel nodes on lymphoscinitigraphic examination. Additional value of freehand SPECT was subjectively scored by the surgeon directly following the biopsy procedure. Freehand SPECT was able to detect 94% of sentinel nodes intraoperatively. Most sentinel nodes not detected (7 out of 9) were located in level I of the neck. Freehand SPECT appeared to be of additional value for facilitating the intraoperative detection of the sentinel node in 24% of procedures. The use of the freehand SPECT system is feasible in the intraoperative detection of sentinel nodes in early stage oral cancer. Freehand SPECT provides helpful information facilitating the SN biopsy procedure in a quarter of cases. However, freehand SPECT cannot detect all SNs which are located in the vicinity of the injection site. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Design and simulation of a high-resolution stationary SPECT system for small animals

    NASA Astrophysics Data System (ADS)

    Beekman, Freek J.; Vastenhouw, Brendan

    2004-10-01

    Exciting new SPECT systems can be created by combining pinhole imaging with compact high-resolution gamma cameras. These new systems are able to solve the problem of the limited sensitivity-resolution trade-off that hampers contemporary small animal SPECT. The design presented here (U-SPECT-III) uses a set of detectors placed in a polygonal configuration and a cylindrical collimator that contains 135 pinholes arranged in nine rings. Each ring contains 15 gold pinhole apertures that focus on the centre of the cylinder. A non-overlapping projection is acquired via each pinhole. Consequently, when a mouse brain is placed in the central field-of-view, each voxel in the cerebrum can be observed via 130 to 135 different pinholes simultaneously. A method for high-resolution scintillation detection is described that eliminates the depth-of-interaction problem encountered with pinhole cameras, and is expected to provide intrinsic detector resolutions better than 150 µm. By means of simulations U-SPECT-III is compared to a simulated dual pinhole SPECT (DP-SPECT) system with a pixelated array consisting of 2.0 × 2.0 mm NaI crystals. Analytic calculations indicate that the proposed U-SPECT-III system yields an almost four times higher linear and about sixty times higher volumetric system resolution than DP-SPECT, when the systems are compared at matching system sensitivity. In addition, it should be possible to achieve a 15 up to 30 times higher sensitivity with U-SPECT-III when the systems are compared at equal resolution. Simulated images of a digital mouse-brain phantom show much more detail with U-SPECT-III than with DP-SPECT. In a resolution phantom, 0.3 mm diameter cold rods are clearly visible with U-SPECT-III, whereas with DP-SPECT the smallest visible rods are about 0.6-0.8 mm. Furthermore, with U-SPECT-III, the image deformations outside the central plane of reconstruction that hamper conventional pinhole SPECT are strongly suppressed. Simulation results indicate

  2. Non-ketotic hyperglycaemic chorea: a SPECT study.

    PubMed

    Chang, M H; Li, J Y; Lee, S R; Men, C Y

    1996-04-01

    To study regional blood flow of the striatum in non-ketotic hyperglycaemic choreic patients. Brain SPECT was performed with intravenous injection of 20 mCi 99mTc hexamethylpropylene amineoxime in six non-ketotic hyperglycaemic choreic patients and 10 age matched patients with a similar level of hyperglycaemia without chorea as a control. The focal perfusion defects were analysed by visual interpretation and semiquantitative determination with reference to homolateral occipital blood flow. The measured blood flow of striatum on the contralateral side of chorea was significantly decreased. Hypometabolism of the striatum is seen not only in Huntington's disease, but also in non-ketotic hyperglycaemic chorea. Hypofunction of the striatum is a possible common pathogenesis in the development of contralateral chorea in different diseases. Furthermore, the sensitivity and reliability of SPECT is as good as PET in assessing choreic patients.

  3. Thallium-201 SPECT imaging of brain tumors: Methods and results

    SciTech Connect

    Kim, K.T.; Black, K.L.; Marciano, D.; Mazziotta, J.C.; Guze, B.H.; Grafton, S.; Hawkins, R.A.; Becker, D.P. )

    1990-06-01

    Recent studies suggest that thallium-201 ({sup 201}Tl) planar scans of brain tumors more accurately reflect viable tumor burden than CT, MRI, or radionuclide studies with other single-photon emitting compounds. We have previously reported the utility of {sup 201}Tl SPECT index in distinguishing low- from high-grade gliomas elsewhere. Here we describe the technical considerations of deriving a simple {sup 201}Tl index, based on uptake in the tumor normalized to homologous contralateral tissue, from SPECT images of brain tumors. We evaluated the importance of consistently correcting for tissue attenuation, as it may achieve better lesion discrimination on qualitative inspection, and the methodologic limitations imposed by partial volume effects at the limits of resolution.

  4. Cerebral blood flow imaging with thallium-201 diethyldithiocarbamate SPECT

    SciTech Connect

    van Royen, E.A.; de Brune, J.F.H.; Hill, T.C.; Vyth, A.; Limburg, M.; Byse, B.L.; O'Leary, D.H.; de Jong, J.M.; Hijdra, A.; van der Schoot, J.B.

    1987-02-01

    Thallium-201 diethyldithiocarbamate ((/sup 201/TI)DDC) was studied in humans as an agent for cerebral blood flow imaging. Brain uptake proved to be complete 90 sec after injection with no appreciable washout or redistribution for hours. Intracarotid injection suggested an almost 100% extraction during the first passage. Whole-body distribution studies demonstrated a brain uptake of 4.3% of the dose compared with 0.9% for (/sup 201/TI)chloride. No differences were found in the distribution of (/sup 201/TI)DDC versus (/sup 201/TI)chloride in other organs. After the injection of 3 mCi /sup 201/TI, good quality single photon emission computed tomographic (SPECT) images of the brain were obtained with both a rotating gamma camera and a multidetector system. In ischemic brain disease, perfusion defects were easily demonstrated. We conclude that (/sup 201/TI)DDC is a suitable radiopharmaceutical for SPECT studies of cerebral blood flow.

  5. Recent advances in cardiac SPECT instrumentation and system design.

    PubMed

    Smith, Mark F

    2013-08-01

    Recent advances in clinical cardiac SPECT instrumentation are reviewed from a systems perspective. New hardware technologies include pixelated scintillator and semiconductor detector elements; photodetectors such as position-sensitive photomultiplier tubes (PSPMT), avalanche photodiodes (APD) and silicon photomultipliers (SiPM); and novel cardiac collimation methods. There are new approaches for positioning detectors and controlling their motion during cardiac imaging. Software technology advances include iterative image reconstruction with modeling of Poisson statistics and depth-dependent collimator response. These new technologies enable faster acquisitions, the lowering of administered activity and radiation dose, and improved image resolution. Higher sensitivity collimators are a significant factor enabling faster acquisitions. Several clinical systems incorporating new technologies are discussed and different system designs can achieve similar performance. With detector elements such as APDs, SiPMs and semiconductors that are insensitive to magnetic fields, the potential for cardiac SPECT imagers that are MRI compatible opens up new frontiers in clinical cardiac research and patient care.

  6. Accuracy of quantitative reconstructions in SPECT/CT imaging

    NASA Astrophysics Data System (ADS)

    Shcherbinin, S.; Celler, A.; Belhocine, T.; van der Werf, R.; Driedger, A.

    2008-09-01

    The goal of this study was to determine the quantitative accuracy of our OSEM-APDI reconstruction method based on SPECT/CT imaging for Tc-99m, In-111, I-123, and I-131 isotopes. Phantom studies were performed on a SPECT/low-dose multislice CT system (Infinia-Hawkeye-4 slice, GE Healthcare) using clinical acquisition protocols. Two radioactive sources were centrally and peripherally placed inside an anthropometric Thorax phantom filled with non-radioactive water. Corrections for attenuation, scatter, collimator blurring and collimator septal penetration were applied and their contribution to the overall accuracy of the reconstruction was evaluated. Reconstruction with the most comprehensive set of corrections resulted in activity estimation with error levels of 3-5% for all the isotopes.

  7. Delayed redistribution in thallium 201 SPECT myocardial perfusion studies

    SciTech Connect

    Ziessman, H.A.; Keyes, J.W. Jr.; Fox, L.M.; Green, C.E.; Fox, S.M. )

    1989-11-01

    Stress {sup 201}Tl myocardial perfusion studies are useful in differentiating viable, reversibly ischemic from infarcted myocardium. A perfusion defect that shows redistribution 2 to 4 h after {sup 201}Tl injection is diagnostic of ischemia, while a fixed defect suggests infarction. However, occasional patients with a fixed defect at 4 h have redistribution at 24 h. This study evaluates the frequency and significance of this delayed redistribution with SPECT {sup 201}Tl. Patients with either no or incomplete redistribution at 4 h had repeat imaging 18 to 48 h later. Delayed redistribution was seen in 8/26 (31 percent). Four had incomplete and four had no redistribution at 4 h. Delayed redistribution with SPECT {sup 201}Tl is more common than generally appreciated, and we recommend delayed images in patients with fixed perfusion defects or incomplete redistribution at 4-h imaging, particularly in patients with previous infarctions for whom a revascularization procedure is being considered.

  8. SPECT study of regional cerebral blood flow in Alzheimer disease

    SciTech Connect

    Bonte, F.J.; Ross, E.D.; Chehabi, H.H.; Devous, M.D. Sr.

    1986-07-01

    A common cause of dementia in late midlife and old age is Alzheimer disease (AD), which affects more than one in 20 individuals over the age of 65. Past studies of regional cerebral blood flow (rCBF) in patients with AD here suggested blood flow abnormalities, but findings have differed. We have studied 37 patients diagnosed as having AD with inhalation and washout of /sup 133/Xe and single-photon emission computed tomography (SPECT), obtaining evidence of abnormal rCBF patterns in 19. Flow reductions were most common in the temporoparietal regions and were occasionally found in the frontal areas. Investigators using positron-emission tomography (PET) have identified similar findings with respect to rCBF and regional oxygen, glucose, and protein metabolism. The SPECT determination of rCBF, which gives information similar to that provided by PET, may assume importance in the diagnosis of AD and in the differential diagnosis of the dementias.

  9. 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

  10. Dual-headed SPECT for awake animal brain imaging

    SciTech Connect

    Lee, Seung Joon; Weisenberger, A G; McKisson, J; Goddard Jr, James Samuel; Baba, Justin S; Smith, M F

    2011-01-01

    Abstract- Motion-corrected awake animal imaging is needed for normal-state investigations of models of neurological disease and brain activity. The awake animal brain SPECT/CT system, AwakeSPECT at Johns Hopkins University has in the past used a single gamma camera for imaging. Enhancements have been made by adding a pinhole collimator to the second gamma camera at the opposite side which has been previously equipped parallel hole collimator. Geometry calibration was performed using a custom built quality control phantom containing three Co-57 point sources and applied to the tomographic reconstruction code. Hot-rod phantom scans with Tc-99m were performed to test sensitivity and resolution improvements. The reconstruction results show significant resolution and sensitivity improvements.

  11. Dual-headed SPECT for awake animal brain imaging

    SciTech Connect

    S. Lee, B. Kross, D. Weisenberger, J. McKisson, J.S. Goddard, J.S. Baba, M.S. Smith

    2012-02-01

    Motion-corrected awake animal imaging is needed for normal-state investigations of models of neurological disease and brain activity. The awake animal brain SPECT/CT system, AwakeSPECT at Johns Hopkins University has in the past used a single gamma camera for imaging. Enhancements have been made by adding a pinhole collimator to the second gamma camera at the opposite side which has been previously equipped parallel hole collimator. Geometry calibration was performed using a custom built quality control phantom containing three Co-57 point sources and applied to the tomographic reconstruction code. Hot-rod phantom scans with Tc-99m were performed to test sensitivity and resolution improvements. The reconstruction results show significant resolution and sensitivity improvements.

  12. High-order total variation minimization for interior SPECT

    NASA Astrophysics Data System (ADS)

    Yang, Jiansheng; Yu, Hengyong; Jiang, Ming; Wang, Ge

    2012-01-01

    Recently, we developed an approach for solving the computed tomography (CT) interior problem based on the high-order TV (HOT) minimization, assuming that a region-of-interest (ROI) is piecewise polynomial. In this paper, we generalize this finding from the CT field to the single-photon emission computed tomography (SPECT) field, and prove that if an ROI is piecewise polynomial, then the ROI can be uniquely reconstructed from the SPECT projection data associated with the ROI through the HOT minimization. Also, we propose a new formulation of HOT, which has an explicit formula for any n-order piecewise polynomial function, while the original formulation has no explicit formula for n ⩾ 2. Finally, we verify our theoretical results in numerical simulation, and discuss relevant issues.

  13. A novel SPECT camera for molecular imaging of the prostate

    NASA Astrophysics Data System (ADS)

    Cebula, Alan; Gilland, David; Su, Li-Ming; Wagenaar, Douglas; Bahadori, Amir

    2011-10-01

    The objective of this work is to develop an improved SPECT camera for dedicated prostate imaging. Complementing the recent advancements in agents for molecular prostate imaging, this device has the potential to assist in distinguishing benign from aggressive cancers, to improve site-specific localization of cancer, to improve accuracy of needle-guided prostate biopsy of cancer sites, and to aid in focal therapy procedures such as cryotherapy and radiation. Theoretical calculations show that the spatial resolution/detection sensitivity of the proposed SPECT camera can rival or exceed 3D PET and further signal-to-noise advantage is attained with the better energy resolution of the CZT modules. Based on photon transport simulation studies, the system has a reconstructed spatial resolution of 4.8 mm with a sensitivity of 0.0001. Reconstruction of a simulated prostate distribution demonstrates the focal imaging capability of the system.

  14. 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.

  15. Anamorphic preclinical SPECT imaging with high-resolution silicon double-sided strip detectors

    NASA Astrophysics Data System (ADS)

    Durko, Heather L.

    Preclinical single-photon emission computed tomography (SPECT) is an essential tool for studying progression, response to treatment, and physiological changes in small animal models of human disease. The wide range of imaging applications is often limited by the static design of many preclinical SPECT systems. We have developed a prototype imaging system that replaces the standard static pinhole aperture with two sets of movable, keel-edged copper-tungsten blades configured as crossed (skewed) slits. These apertures can be positioned independently between the object and detector, producing an anamorphic image in which the axial and transaxial magnications are not constrained to be equal. We incorporated a 60 mm x 60 mm, millimeter-thick megapixel silicon double-sided strip detector that permits ultrahigh-resolution imaging. While the stopping power of silicon is low for many common clinical radioisotopes, its performance is sufficient in the range of 20-60 keV to allow practical imaging experiments. The low-energy emissions of 125I fall within this energy window, and the 60-day half life provides an advantage for longitudinal studies. The flexible nature of this system allows the future application of adaptive imaging techniques. We have demonstrated ˜225-mum axial and ˜175-mum transaxial resolution across a 2.65 cm3 cylindrical field of view, as well as the capability for simultaneous multi-isotope acquisitions. We describe the key advancements that have made this system operational, including bringing up a new detector readout ASIC, development of detector control software and data-processing algorithms, and characterization of operating characteristics. We describe design and fabrication of the adjustable slit aperture platform, as well as the development of an accurate imaging forward model and its application in a novel geometric calibration technique and a GPU-based ultrahigh-resolution reconstruction code.

  16. Accelerated SPECT Monte Carlo Simulation Using Multiple Projection Sampling and Convolution-Based Forced Detection

    PubMed Central

    Liu, Shaoying; King, Michael A.; Brill, Aaron B.; Stabin, Michael G.; Farncombe, Troy H.

    2010-01-01

    Monte Carlo (MC) is a well-utilized tool for simulating photon transport in single photon emission computed tomography (SPECT) due to its ability to accurately model physical processes of photon transport. As a consequence of this accuracy, it suffers from a relatively low detection efficiency and long computation time. One technique used to improve the speed of MC modeling is the effective and well-established variance reduction technique (VRT) known as forced detection (FD). With this method, photons are followed as they traverse the object under study but are then forced to travel in the direction of the detector surface, whereby they are detected at a single detector location. Another method, called convolution-based forced detection (CFD), is based on the fundamental idea of FD with the exception that detected photons are detected at multiple detector locations and determined with a distance-dependent blurring kernel. In order to further increase the speed of MC, a method named multiple projection convolution-based forced detection (MP-CFD) is presented. Rather than forcing photons to hit a single detector, the MP-CFD method follows the photon transport through the object but then, at each scatter site, forces the photon to interact with a number of detectors at a variety of angles surrounding the object. This way, it is possible to simulate all the projection images of a SPECT simulation in parallel, rather than as independent projections. The result of this is vastly improved simulation time as much of the computation load of simulating photon transport through the object is done only once for all projection angles. The results of the proposed MP-CFD method agrees well with the experimental data in measurements of point spread function (PSF), producing a correlation coefficient (r2) of 0.99 compared to experimental data. The speed of MP-CFD is shown to be about 60 times faster than a regular forced detection MC program with similar results. PMID:20811587

  17. Efficacy of (99m)Tc-EDDA/HYNIC-TOC SPECT/CT scintigraphy in Graves' ophthalmopathy.

    PubMed

    Zhao, Rong; Wang, Jiang; Deng, Jinglan; Yang, Weidong; Wang, Jing

    2012-01-01

    The aim of this study was to investigate the predictive role of the orbital somatostatin receptor scintigraphy with (99m)Tc-EDDA/HYNIC-TOC ((99m)Tc-TOC) to detect clinical stage of Graves' ophthalmopathy and the response to corticosteroid therapy. The subjects of the experiment were 46 patients with Graves' ophthalmopathy (GO) and four volunteers without eye disease or GO as the normal group (NG). Single photon emission computed tomography (SPECT), computed tomography (CT) and the left and right lateral position planar imaging of the heads of the all subjects were obtained 4 h after the intravenous injection of 555 MBq of (99m)Tc-TOC. The (99m)Tc-TOC SPECT/CT was repeated 3 months later. 35 (35/46) patients were received corticosteroid therapy (prednisolone, 10 mg po tid ) for 3 months, however, the other 11 patients as control groups did not receive any treatment. The treatment effect was evaluated both by the orbital (99m)Tc-TOC uptake and NOSPECS. A significant decrease in the O/OC ratio was observed in 22 GO patients between pre- and post-treatment (1.64 ± 0.13 vs. 1.21 ± 0.09, P < 0.05). There were neither significant difference of the O/OC ratio in 13 GO patients between pre- and post-treatment periods, nor significant difference in the 9 (9/11) patients before and after three months. Orbital (99m)Tc-TOC scintigraphy is a feasible technique to estimate the Graves' ophthalmopathy activity and predict the response to subsequent corticosteroid therapy in GO patients. The technique could be a useful tool for physicians not familiar with CAS determination.

  18. Unlocking the Secrets of the Brain, Part II: A Continuing Look at Techniques for Exploring the Brain.

    ERIC Educational Resources Information Center

    Powledge, Tabitha M.

    1997-01-01

    Describes techniques for delving into the brain including positron emission tomography (PET), single photon emission computed tomography (SPECT), electroencephalogram (EEG), magnetoencephalography (MEG), transcranial magnetic stimulation (TMS), and low-tech indirect studies. (JRH)

  19. Unlocking the Secrets of the Brain, Part II: A Continuing Look at Techniques for Exploring the Brain.

    ERIC Educational Resources Information Center

    Powledge, Tabitha M.

    1997-01-01

    Describes techniques for delving into the brain including positron emission tomography (PET), single photon emission computed tomography (SPECT), electroencephalogram (EEG), magnetoencephalography (MEG), transcranial magnetic stimulation (TMS), and low-tech indirect studies. (JRH)

  20. [Brain SPECT in a case of Wernicke Korsakoff syndrome].

    PubMed

    Hervás-Benito, I; Pérez-Velasco, R

    In this article we report a 44 year old male with chronic alcoholism as antecedent and Wernicke Korsakoff s syndrome, studied with brain CT, MR and SPECT. In this work we review the different conclusion obtained with different studies and in different stages of the chronic alcoholism disease. Although several authors have described impaired frontal blood flow in the Wernicke Korsakoff s syndrome, in our case the parietal, temporal and occipital cortex were the most affected.

  1. Compact CT/SPECT Small-Animal Imaging System

    PubMed Central

    Kastis, George A.; Furenlid, Lars R.; Wilson, Donald W.; Peterson, Todd E.; Barber, H. Bradford; Barrett, Harrison H.

    2015-01-01

    We have developed a dual-modality CT/SPECT imaging system for small-animal imaging applications. The X-ray system comprises a commercially available micro-focus X-ray tube and a CCD-based X-ray camera. X-ray transmission measurements are performed based on cone-beam geometry. Individual projections are acquired by rotating the animal about a vertical axis in front of the CCD detector. A high-resolution CT image is obtained after reconstruction using an ordered subsets-expectation maximization (OS-EM) reconstruction algorithm. The SPECT system utilizes a compact semiconductor camera module previously developed in our group. The module is mounted perpendicular to the X-ray tube/CCD combination. It consists of a 64×64 pixellated CdZnTe detector and a parallel-hole tungsten collimator. The field of view is 1 square inch. Planar projections for SPECT reconstruction are obtained by rotating the animal in front of the detector. Gamma-ray and X-ray images are presented of phantoms and mice. Procedures for merging the anatomical and functional images are discussed. PMID:26538684

  2. SVD-based evaluation of multiplexing in multipinhole SPECT systems.

    PubMed

    Jorgensen, Aaron K; Zeng, Gengsheng L

    2008-01-01

    Multipinhole SPECT system design is largely a trial-and-error process. General principles can give system designers a general idea of how a system with certain characteristics will perform. However, the specific performance of any particular system is unknown before the system is tested. The development of an objective evaluation method that is not based on experimentation would facilitate the optimization of multipinhole systems. We derive a figure of merit for prediction of SPECT system performance based on the entire singular value spectrum of the system. This figure of merit contains significantly more information than the condition number of the system, and is therefore more revealing of system performance. This figure is then compared with simulated results of several SPECT systems and is shown to correlate well to the results of the simulations. The proposed figure of merit is useful for predicting system performance, but additional steps could be taken to improve its accuracy and applicability. The limits of the proposed method are discussed, and possible improvements to it are proposed.

  3. Dynamic heart-in-thorax phantom for functional SPECT

    SciTech Connect

    Celler, A.; Lyster, D.; Farncombe, T.

    1996-12-31

    We have designed and built a dynamic heart-in-thorax phantom to be used as a primary tool during the experimental verification of the performance of the quantitative dynamic functional imaging method we are developing for standard rotating single photon emission computed tomography (SPECT) cameras. The phantom consists of two independent parts (i) a dynamic heart model with the possibility of mounting {open_quotes}defects{close_quotes} inside it and (ii) a non-uniform thorax model with lungs and spinal cord, and uses the fact that the washout of a tracer by dilution is governed by a linear first order equation, the same type of equation as is used to model time-activity distribution in myocardial viability studies. Tests of the dynamic performance of the phantom in planar scanning mode have confirmed the validity of these assumptions. Also the preliminary results obtained in SPECT mode show that the values of characteristic times could be experimentally determined and that these values agreed well with the values preset on the phantom. We consider that the phantom is ready for extensive use in studies into development of the dynamic SPECT method.

  4. 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.

  5. 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

  6. Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

    SciTech Connect

    Aguiar, Pablo; Pino, Francisco; Silva-Rodríguez, Jesús; Pavía, Javier; Ros, Doménec; Ruibal, Álvaro; and others

    2014-03-15

    Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the

  7. Evaluation of a compact, high-resolution SPECT detector based on digital silicon photomultipliers.

    PubMed

    Bouckaert, Carmen; Vandenberghe, Stefaan; Van Holen, Roel

    2014-12-07

    MicroSPECT is one of the main functional imaging techniques used in the preclinical setting. Even though high-resolution images can be obtained with currently available systems, their sensitivity is often quite low due to the use of multi-pinhole collimation. This results in long acquisition times and hampers dynamic imaging. However, it has already been shown that this limited sensitivity can be overcome using high-resolution detectors. In this article, we therefore investigated the use of a digital photon counter (DPC) in combination with a 2 mm thick monolithic LYSO crystal for SPECT imaging. These light sensors contain arrays of avalanche photodiodes whose signals are directly digitised. The DPCs have the advantage that they are very compact, have a high intrinsic resolution, are MR compatible and allow disabling cells with a high dark count rate. In order to investigate the influence of the temperature dependent dark count rate on the detector performance, we compared it at 3 °C and 18 °C. At 3 °C, we observed an energy resolution of 28.8% and an intrinsic spatial resolution of 0.48 mm. Furthermore, the count rate at 10% loss is 60 kcps. Next, we looked at the event loss at 18 °C caused by the higher dark count rate and found a 5% loss compared to the 3 °C measurements. At this higher temperature the energy resolution becomes 29.2% and the intrinsic spatial resolution decreases to 0.52 mm. Due to the 5% count loss, the count rate at 10% loss increases to 63 kcps. A small degradation of the detector performance is thus observed at 18 °C.These results show the usefulness of this detector for SPECT imaging together with its excellent intrinsic spatial resolution. A drawback of the detector is its low, spatially varying energy resolution. Even though the detection efficiency and intrinsic spatial resolution are better at 3 °C, results are still acceptable at 18 °C.

  8. Optimizing SPECT SISCOM analysis to localize seizure-onset zone by using varying z scores.

    PubMed

    Newey, Christopher R; Wong, Chong; Wang, Z Irene; Chen, Xin; Wu, Guiyun; Alexopoulos, Andreas V

    2013-05-01

    Subtraction ictal single photon emission computed tomography (SPECT) co-registered to magnetic resonance imaging (MRI) (SISCOM) is a useful modality to identify epileptogenic focus. Using this technique, several studies have generally considered the area of highest ictal hyperperfusion, as outlined by thresholding the difference images with a standard z score of 2, to be highly concordant to the epileptogenic focus. In clinical practice, several factors influence ictal hyperperfusion and using different SISCOM thresholds can be helpful. We aimed to systematically evaluate the localizing value of various z scores (1, 1.5, 2, and 2.5) in a seizure-free cohort following resective epilepsy surgery, and to examine the localizing information of perfusion patterns observed at each z score. Twenty-six patients were identified as having ictal-interictal SPECT images, preoperative and postoperative MRI studies, and having remained seizure free for at least 6 months after temporal or extratemporal surgical resection. SISCOM analysis was performed using preoperative MRI studies, and then blindly reviewed for localization of hyperperfused regions. With the added information from postoperative, coregistered MRI, perfusion patterns were determined. Using pair-wise comparisons, we found that the optimal z score for SPECT-SISCOM localization of the epileptogenic zone was 1.5, not the commonly used z score of 2. The z score of 1.5 was 84.8% sensitive and 93.8% specific. The z score of 1.5 had a moderate interrater agreement (0.70). When an hourglass configuration hyperperfusion pattern was present, a trend toward correctly localizing the seizure onset region was suggested (100% of the 11 observed occurrences). Nonetheless this trend was not statistically significant, possibly reflecting the small number of occurrences in our study. SISCOM is a useful modality in evaluating patients for epilepsy surgery. This study shows that the z score of 1.5 represents a highly sensitive and

  9. A stripe sign on 99mTc-Technegas SPECT in pulmonary emphysema.

    PubMed

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

    2008-06-01

    By focusing on a stripe sign (interposed preserved radioactivity between central defects and pleural surface of the lung), the cross-sectional ventilation difference between the central and peripheral lung in pulmonary emphysema was evaluated on Tc-Technegas SPECT, and compared with other forms of chronic obstructive pulmonary disease (COPD). Technegas and perfusion SPECT were performed in 47 patients with relatively advanced emphysema, 15 patients with other forms of COPD without alveolar destruction and six controls. The presence or absence of a stripe sign was evaluated at upper, middle and lower lung zones on both SPECT. At stripe sign-positive lung zones on Technegas SPECT in pulmonary emphysema, the pattern of low attenuation areas (LAAs) distribution on X-ray CT was also evaluated. Of the total of 282 lung zones in patients with emphysema, a stripe sign was positive on Technegas SPECT at 153 (54.2%) zones in 27 (57.4%) patients, although less frequently positive on perfusion SPECT at 166 (58.8%) zones in 30 (63.8%) patients. This sign was negative on Technegas SPECT throughout the stripe sign-negative zones on perfusion SPECT. Throughout the lung zones in controls and patients with other forms of COPD, this sign was negative both on Technegas and perfusion SPECT. On X-ray CT, 124 (81%) of 153 stripe-positive lung zones on Technegas SPECT in pulmonary emphysema showed central lung-dominant LAA. In contrast to other forms of COPD, a stripe sign was frequently positive on Technegas SPECT in relatively advanced emphysema, with central-lung dominant LAA on X-ray CT. Relative preservation of peripheral lung ventilation seems to be a characteristic feature of this disease, indicating a lower susceptibility of the peripheral lung for alveolar destruction.

  10. Radiation-Based Medical Imaging Techniques: An Overview

    NASA Astrophysics Data System (ADS)

    Prior, John O.; Lecoq, Paul

    This chapter will present an overview of two radiation-based medical imaging techniques using radiopharmaceuticals used in nuclear medicine/molecular imaging, namely, single-photon emission computed tomography (SPECT) and positron emission tomography (PET). The relative merits in terms of radiation sensitivity and image resolution of SPECT and PET will be compared to the main conventional radiologic modalities that are computed tomography (CT) and magnetic resonance (MR) imaging. Differences in terms of temporal resolution will also be outlined, as well as the other similarities and dissimilarities of these two techniques, including their latest and upcoming multimodality combination. The main clinical applications are briefly described and examples of specific SPECT and PET radiopharmaceuticals are listed. SPECT and PET imaging will be then further detailed in the two subsequent chapters describing in greater depth the basics and future trends of each technique (see Chaps. 37, "SPECT Imaging: Basics and New Trends" 10.1007/978-3-642-13271-1_37 and 38, "PET Imaging: Basics and New Trends" 10.1007/978-3-642-13271-1_38.

  11. 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

  12. Comparison of heterogeneity quantification algorithms for brain SPECT perfusion images

    PubMed Central

    2012-01-01

    Background Several algorithms from the literature were compared with the original random walk (RW) algorithm for brain perfusion heterogeneity quantification purposes. Algorithms are compared on a set of 210 brain single photon emission computed tomography (SPECT) simulations and 40 patient exams. Methods Five algorithms were tested on numerical phantoms. The numerical anthropomorphic Zubal head phantom was used to generate 42 (6 × 7) different brain SPECT simulations. Seven diffuse cortical heterogeneity levels were simulated with an adjustable Gaussian noise function and six focal perfusion defect levels with temporoparietal (TP) defects. The phantoms were successively projected and smoothed with Gaussian kernel with full width at half maximum (FWHM = 5 mm), and Poisson noise was added to the 64 projections. For each simulation, 5 Poisson noise realizations were performed yielding a total of 210 datasets. The SPECT images were reconstructed using filtered black projection (Hamming filter: α = 0.5). The five algorithms or measures tested were the following: the coefficient of variation, the entropy and local entropy, fractal dimension (FD) (box counting and Fourier power spectrum methods), the gray-level co-occurrence matrix (GLCM), and the new RW. The heterogeneity discrimination power was obtained with a linear regression for each algorithm. This regression line is a mean function of the measure of heterogeneity compared to the different diffuse heterogeneity and focal defect levels generated in the phantoms. A greater slope denotes a larger separation between the levels of diffuse heterogeneity. The five algorithms were computed using 40 99mTc-ethyl-cysteinate-dimer (ECD) SPECT images of patients referred for memory impairment. Scans were blindly ranked by two physicians according to the level of heterogeneity, and a consensus was obtained. The rankings obtained by the algorithms were compared with the physicians' consensus ranking. Results The GLCM method

  13. Comparison of heterogeneity quantification algorithms for brain SPECT perfusion images.

    PubMed

    Modzelewski, Romain; Janvresse, Elise; de la Rue, Thierry; Vera, Pierre

    2012-07-20

    Several algorithms from the literature were compared with the original random walk (RW) algorithm for brain perfusion heterogeneity quantification purposes. Algorithms are compared on a set of 210 brain single photon emission computed tomography (SPECT) simulations and 40 patient exams. Five algorithms were tested on numerical phantoms. The numerical anthropomorphic Zubal head phantom was used to generate 42 (6 × 7) different brain SPECT simulations. Seven diffuse cortical heterogeneity levels were simulated with an adjustable Gaussian noise function and six focal perfusion defect levels with temporoparietal (TP) defects. The phantoms were successively projected and smoothed with Gaussian kernel with full width at half maximum (FWHM = 5 mm), and Poisson noise was added to the 64 projections. For each simulation, 5 Poisson noise realizations were performed yielding a total of 210 datasets. The SPECT images were reconstructed using filtered black projection (Hamming filter: α = 0.5).The five algorithms or measures tested were the following: the coefficient of variation, the entropy and local entropy, fractal dimension (FD) (box counting and Fourier power spectrum methods), the gray-level co-occurrence matrix (GLCM), and the new RW.The heterogeneity discrimination power was obtained with a linear regression for each algorithm. This regression line is a mean function of the measure of heterogeneity compared to the different diffuse heterogeneity and focal defect levels generated in the phantoms. A greater slope denotes a larger separation between the levels of diffuse heterogeneity.The five algorithms were computed using 40 99mTc-ethyl-cysteinate-dimer (ECD) SPECT images of patients referred for memory impairment. Scans were blindly ranked by two physicians according to the level of heterogeneity, and a consensus was obtained. The rankings obtained by the algorithms were compared with the physicians' consensus ranking. The GLCM method (slope = 58.5), the fractal

  14. Direction-dependent localization errors in SPECT images

    SciTech Connect

    Roper, Justin; Bowsher, James; Yin Fangfang

    2010-09-15

    Purpose: Single photon emission computed tomography (SPECT) is being investigated for imaging inside radiation therapy treatment rooms to localize biological targets. Here, computer simulations were used to analyze locational and directional dependencies in localization errors and to assess the effects of spatial resolution modeling and observer normalization on localization performance. Methods: SPECT images of the XCAT phantom, containing 12 hot tumors, were reconstructed with detector response function compensation (DRC) and without DRC (nDRC). Numerical observers were forced to select the most suspicious tumor location, using normalized cross correlation (NXC) or un-normalized cross correlation (XC), from 3 cm diameter search volumes that each contained only one tumor. For each tumor site, localization was optimized as a function of the iteration number and postreconstruction smoothing. Localization error, the distance between true and estimated tumor positions, was calculated across the ensembles of 80 images. Direction-dependent localization bias and precision were estimated from the image ensemble. Results: For the six superficial tumors in close proximity to the detector trajectory, mean localization errors were <2 mm and were lowest or comparable using DRC-NXC, though differences from DRC-XC and nDRC-NXC were not statistically significant. DRC-NXC did provide statistically significantly better localization than nDRC-XC for five of these six tumors. At the other six sites where attenuation was more severe and the distance was generally greater between the tumor and detector, DRC typically did not show better localization than nDRC. Observer normalization improved the localization substantially for a tumor near the hotter heart. Localization errors were anisotropic and dependent on tumor location relative to the detector trajectory. Conclusions: This computer-simulation study compared localization performance for normalized and un-normalized numerical

  15. GATE - Geant4 Application for Tomographic Emission: a simulation toolkit for PET and SPECT

    PubMed Central

    Jan, S.; Santin, G.; Strul, D.; Staelens, S.; Assié, K.; Autret, D.; Avner, S.; Barbier, R.; Bardiès, M.; Bloomfield, P. M.; Brasse, D.; Breton, V.; Bruyndonckx, P.; Buvat, I.; Chatziioannou, A. F.; Choi, Y.; Chung, Y. H.; Comtat, C.; Donnarieix, D.; Ferrer, L.; Glick, S. J.; Groiselle, C. J.; Guez, D.; Honore, P.-F.; Kerhoas-Cavata, S.; Kirov, A. S.; Kohli, V.; Koole, M.; Krieguer, M.; van der Laan, D. J.; Lamare, F.; Largeron, G.; Lartizien, C.; Lazaro, D.; Maas, M. C.; Maigne, L.; Mayet, F.; Melot, F.; Merheb, C.; Pennacchio, E.; Perez, J.; Pietrzyk, U.; Rannou, F. R.; Rey, M.; Schaart, D. R.; Schmidtlein, C. R.; Simon, L.; Song, T. Y.; Vieira, J.-M.; Visvikis, D.; Van de Walle, R.; Wieërs, E.; Morel, C.

    2012-01-01

    Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols, and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document, and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at the address http://www-lphe.ep.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects toward the gridification of GATE and its extension to other domains such as dosimetry are also discussed. PMID:15552416

  16. Estimating ROI activity concentration with photon-processing and photon-counting SPECT imaging systems

    NASA Astrophysics Data System (ADS)

    Jha, Abhinav K.; Frey, Eric C.

    2015-03-01

    Recently a new class of imaging systems, referred to as photon-processing (PP) systems, are being developed that uses real-time maximum-likelihood (ML) methods to estimate multiple attributes per detected photon and store these attributes in a list format. PP systems could have a number of potential advantages compared to systems that bin photons based on attributes such as energy, projection angle, and position, referred to as photon-counting (PC) systems. For example, PP systems do not suffer from binning-related information loss and provide the potential to extract information from attributes such as energy deposited by the detected photon. To quantify the effects of this advantage on task performance, objective evaluation studies are required. We performed this study in the context of quantitative 2-dimensional single-photon emission computed tomography (SPECT) imaging with the end task of estimating the mean activity concentration within a region of interest (ROI). We first theoretically outline the effect of null space on estimating the mean activity concentration, and argue that due to this effect, PP systems could have better estimation performance compared to PC systems with noise-free data. To evaluate the performance of PP and PC systems with noisy data, we developed a singular value decomposition (SVD)-based analytic method to estimate the activity concentration from PP systems. Using simulations, we studied the accuracy and precision of this technique in estimating the activity concentration. We used this framework to objectively compare PP and PC systems on the activity concentration estimation task. We investigated the effects of varying the size of the ROI and varying the number of bins for the attribute corresponding to the angular orientation of the detector in a continuously rotating SPECT system. The results indicate that in several cases, PP systems offer improved estimation performance compared to PC systems.

  17. SPECT assay of radiolabeled monoclonal antibodies. Final performance report, March 1992--November 1995

    SciTech Connect

    Jaszczak, R.J.

    1995-12-01

    Research is described in the following areas: development and evaluation quantitatively of reconstruction algorithms with improved compensations for attenuation, scatter, and geometric collimator response; evaluation of single photon emission computed tomography (SPECT) quantification of iodine 123 and astatine 211; and the development and evaluation of SPECT pinhole imaging for low and medium energy photons.

  18. 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.

  19. Constrictive pericarditis causing a positive TI-201 SPECT stress test for myocardial ischemia

    SciTech Connect

    Matthews, R.J.; Lightfoote, J.; Grusd, R.S. )

    1990-08-01

    A case of constritive pericarditis was demonstrated by a positive thallium SPECT stress test for myocardial ischemia. After pericardiectomy, the repeat thallium stress test was normal. The disappearance of the criteria for a positive test suggests that constrictive pericarditis can cause myocardial ischemia, which can be demonstrated by thallium SPECT stress testing.

  20. Implementation of Angular Response Function modeling in SPECT simulations with GATE

    PubMed Central

    Descourt, P; Carlier, T; Du, Y; Song, X; Buvat, I; Frey, E C; Bardies, M; Tsui, B M W; Visvikis, D

    2010-01-01

    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, is 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 364keV source seen with the same SPECT system. The ARF-based and the standard GATE simulation results also agreed very well when considering a 4-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. PMID:20393239

  1. Implementation of angular response function modeling in SPECT simulations with GATE.

    PubMed

    Descourt, P; Carlier, T; Du, Y; Song, X; Buvat, I; Frey, E C; Bardies, M; Tsui, B M W; Visvikis, D

    2010-05-07

    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.

  2. A comparison of MR-based attenuation correction in PET versus SPECT

    NASA Astrophysics Data System (ADS)

    Marshall, H. R.; Stodilka, R. Z.; Theberge, J.; Sabondjian, E.; Legros, A.; Deans, L.; Sykes, J. M.; Thompson, R. T.; Prato, F. S.

    2011-07-01

    Attenuation correction (AC) is a critical step in the reconstruction of quantitatively accurate positron emission tomography (PET) and single photon emission computed tomography (SPECT) images. Several groups have proposed magnetic resonance (MR)-based AC algorithms for application in hybrid PET/MR systems. However, none of these approaches have been tested on SPECT data. Since SPECT/MR systems are under active development, it is important to ascertain whether MR-based AC algorithms validated for PET can be applied to SPECT. To investigate this issue, two imaging experiments were performed: one with an anthropomorphic chest phantom and one with two groups of canines. Both groups of canines were imaged from neck to abdomen, one with PET/CT and MR (n = 4) and the other with SPECT/CT and MR (n = 4), while the phantom was imaged with all modalities. The quality of the nuclear medicine reconstructions using MR-based attenuation maps was compared between PET and SPECT on global and local scales. In addition, the sensitivity of these reconstructions to variations in the attenuation map was ascertained. On both scales, it was found that the SPECT reconstructions were of higher fidelity than the PET reconstructions. Further, they were less sensitive to changes to the MR-based attenuation map. Thus, MR-based AC algorithms that have been designed for PET/MR can be expected to demonstrate improved performance when used for SPECT/MR.

  3. SPECT/CT: an update on technological developments and clinical applications.

    PubMed

    Ljungberg, Michael; Pretorius, P Hendrik

    2017-01-16

    Functional nuclear medicine imaging with single-photon emission CT (SPECT) in combination with anatomical CT has been commercially available since the beginning of this century. The combination of the two modalities has improved both the sensitivity and specificity of many clinical applications and CT in conjunction with SPECT that allows for spatial overlay of the SPECT data on good anatomy images. Introduction of diagnostic CT units as part of the SPECT/CT system has also potentially allowed for a more cost-efficient use of the equipment. Most of the SPECT systems available are based on the well-known Anger camera principle with NaI(Tl) as a scintillation material, parallel-hole collimators and multiple photomultiplier tubes, which, from the centroid of the scintillation light, determine the position of an event. Recently, solid-state detectors using cadmium-zinc-telluride became available and clinical SPECT cameras employing multiple pinhole collimators have been developed and introduced in the market. However, even if new systems become available with better hardware, the SPECT reconstruction will still be affected by photon attenuation and scatter and collimator response. Compensation for these effects is needed even for qualitative studies to avoid artefacts leading to false positives. This review highlights the recent progress for both new SPECT cameras systems as well as for various data-processing and compensation methods.

  4. Distinction between hemangioma of the liver and hepatocellular carcinoma: value of labeled RBC-SPECT scanning

    SciTech Connect

    Kudo, M.; Ikekubo, K.; Yamamoto, K.; Ibuki, Y.; Hino, M.; Tomita, S.; Komori, H.; Orino, A.; Todo, A.

    1989-05-01

    The role of adding single-photon emission CT (SPECT) to /sup 99m/Tc-labeled RBC imaging of the liver was evaluated by specifically focusing on the differentiation between hepatic hemangioma and hepatocellular carcinoma. Planar RBC imaging followed by blood-pool SPECT scanning was performed in 77 patients with a total of 108 hemangiomas and in 29 patients with a total of 46 hepatocellular carcinomas. All lesions were smaller than 5 cm in diameter. Thirty-six (33%) of 108 hemangiomas were detected by planar delayed RBC imaging, whereas 63 (58%) were detected by the delayed RBC-SPECT scan. The smallest hemangioma shown by delayed RBC-SPECT scanning was 1.4 cm in diameter, compared with 1.7 cm by planar RBC scanning. When confined to nodules larger than 1.4 cm in diameter, 42% of hemangiomas (36/85) were detected by planar delayed RBC imaging, whereas 74% (63/85) were detected by delayed RBC-SPECT. Increase in sensitivity was noted in nodules 2.1-4.0 cm in diameter. No hepatocellular carcinomas were shown by delayed RBC planar or SPECT scans. We concluded that with the addition of SPECT, the sensitivity of delayed RBC scans in the detection of small hemangiomas is considerably improved. Delayed RBC-SPECT scanning can be used to distinguish hemangioma from hepatocellular carcinoma.

  5. SPECT-OPT multimodal imaging enables accurate evaluation of radiotracers for β-cell mass assessments

    PubMed Central

    Eter, Wael A.; Parween, Saba; Joosten, Lieke; Frielink, Cathelijne; Eriksson, Maria; Brom, Maarten; Ahlgren, Ulf; Gotthardt, Martin

    2016-01-01

    Single Photon Emission Computed Tomography (SPECT) has become a promising experimental approach to monitor changes in β-cell mass (BCM) during diabetes progression. SPECT imaging of pancreatic islets is most commonly cross-validated by stereological analysis of histological pancreatic sections after insulin staining. Typically, stereological methods do not accurately determine the total β-cell volume, which is inconvenient when correlating total pancreatic tracer uptake with BCM. Alternative methods are therefore warranted to cross-validate β-cell imaging using radiotracers. In this study, we introduce multimodal SPECT - optical projection tomography (OPT) imaging as an accurate approach to cross-validate radionuclide-based imaging of β-cells. Uptake of a promising radiotracer for β-cell imaging by SPECT, 111In-exendin-3, was measured by ex vivo-SPECT and cross evaluated by 3D quantitative OPT imaging as well as with histology within healthy and alloxan-treated Brown Norway rat pancreata. SPECT signal was in excellent linear correlation with OPT data as compared to histology. While histological determination of islet spatial distribution was challenging, SPECT and OPT revealed similar distribution patterns of 111In-exendin-3 and insulin positive β-cell volumes between different pancreatic lobes, both visually and quantitatively. We propose ex vivo SPECT-OPT multimodal imaging as a highly accurate strategy for validating the performance of β-cell radiotracers. PMID:27080529

  6. SPECT-OPT multimodal imaging enables accurate evaluation of radiotracers for β-cell mass assessments.

    PubMed

    Eter, Wael A; Parween, Saba; Joosten, Lieke; Frielink, Cathelijne; Eriksson, Maria; Brom, Maarten; Ahlgren, Ulf; Gotthardt, Martin

    2016-04-15

    Single Photon Emission Computed Tomography (SPECT) has become a promising experimental approach to monitor changes in β-cell mass (BCM) during diabetes progression. SPECT imaging of pancreatic islets is most commonly cross-validated by stereological analysis of histological pancreatic sections after insulin staining. Typically, stereological methods do not accurately determine the total β-cell volume, which is inconvenient when correlating total pancreatic tracer uptake with BCM. Alternative methods are therefore warranted to cross-validate β-cell imaging using radiotracers. In this study, we introduce multimodal SPECT - optical projection tomography (OPT) imaging as an accurate approach to cross-validate radionuclide-based imaging of β-cells. Uptake of a promising radiotracer for β-cell imaging by SPECT, (111)In-exendin-3, was measured by ex vivo-SPECT and cross evaluated by 3D quantitative OPT imaging as well as with histology within healthy and alloxan-treated Brown Norway rat pancreata. SPECT signal was in excellent linear correlation with OPT data as compared to histology. While histological determination of islet spatial distribution was challenging, SPECT and OPT revealed similar distribution patterns of (111)In-exendin-3 and insulin positive β-cell volumes between different pancreatic lobes, both visually and quantitatively. We propose ex vivo SPECT-OPT multimodal imaging as a highly accurate strategy for validating the performance of β-cell radiotracers.

  7. Recent and future evolutions in NeuroSPECT with particular emphasis on the synergistic use and fusion of imaging modalities.

    PubMed

    d'Asseler, Y M; Koole, M; Lemahieu, I; Achten, E; Boon, P; De Deyn, P P; Dierckx, R A

    1997-09-01

    Recent and future evolutions in neuroSPECT apply to radiopharmaceuticals techniques and the synergistic use of different imaging modalities in the work-up of neurological disorders. The introduction of Technetium labelled perfusion tracers, which could pass the intact blood-brain barrier, together with the implementation of the tomographic principle, by making the conventional gamma camera rotating, enabled estimation of regional cerebral blood flow and indirectly of local brain metabolism. In addition at present Thallium-201 and Tc-99m sestaMIBI allow functional detection of viable tumor tissue, without interference from previous surgery or radiotherapy as seen using CT-scan or MRI. In neurology this has led to the recognition of SPECT by the American Academy of Neurology (Therapeutics and technology subcommittee) as an established or promising tool in major neurological disorders such as dementia, stroke and epilepsy, while other domains such as brain oncology are considered investigational. With regard to radiopharmaceuticals, recent evolutions mainly include the development of mostly Iodine-123 labelled receptor ligands, some of which are already commercially available. For instrumentation advances consist e.g. of multidetector systems equipped with fanbeam collimators, attenuation and scatter correction or coincidence detection. Given the present role for nuclear neurology it may be expected that these additional radiopharmaceutical and technical innovations will continue to stimulate the development of SPECT of the brain. The synergistic use of several imaging techniques such as CT, (functional) MRI, source imaging, SPECT and PET represents a multimodal holistic approach to probe cerebral functions for research and clinical purposes. Clinical indications, in which this synergistic use is illustrated include e.g. support of the clinical diagnosis of dementia of the Alzheimer type, presurgical ictal detection of seizure focus, detection of acute ischemia and

  8. Single photon emission computed tomography (SPECT) and SPECT/low-dose computerized tomography did not increase sensitivity or specificity compared to planar bone scintigraphy for detection of bone metastases in advanced breast cancer.

    PubMed

    Haraldsen, Ate; Bluhme, Henrik; Røhl, Lisbeth; Pedersen, Erik Morre; Jensen, Anders Bonde; Hansen, Eva Boysen; Nellemann, Hanne; Rasmussen, Finn; Morsing, Anni

    2016-01-01

    To evaluate and compare the diagnostic performance of whole-body planar bone scintigraphy (WBS), single photon emission computed tomography (SPECT), SPECT/low-dose computerized tomography (SPECT/ldCT) and SPECT/contrast enhanced diagnostic CT (SPECT/cdCT) in the staging of patients with advanced breast cancer. Seventy-eight patients with recurrence of biopsy-proven breast cancer and suspicion of disseminated disease were investigated with WBS, SPECT, SPECT/ldCT, SPECT/cdCT and MRI performed on the same day in this prospective study. Images were separately analysed in a blinded fashion by radiologists and nuclear medicine physicians regarding the presence of pathological findings. MRI served as reference standard. According to reference standard, 38 of 73 patients had bone metastases. The sensitivity was 87%, 87%, 79%, and 84% and specificity 63%, 71%, 63% and 83% for WBS, SPECT, SPECT/ldCT and SPECT/cdCT. A significantly increased specificity of SPECT/cdCT compared to WBS and SPECT/ldCT was found, and other parameters did not differ significantly between modalities. Additional two patients had bone metastases solely located outside the MRI scan field and seven patients had soft tissue metastases, but no skeletal changes on MRI. WBS, SPECT and SPECT/ldCT were less sensitive than MRI and equally specific for the detection of bone metastases in patients with advanced breast cancer. Based on our findings, we suggest that initial staging include WBS, MRI of the spine and CT for soft tissue evaluation. Further studies may clarify the potential benefits of whole-body MRI and 18F-NaF PET/CT or 18F-FDG PET/CT. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  9. Handheld single photon emission computed tomography (handheld SPECT) navigated video-assisted thoracoscopic surgery of computer tomography-guided radioactively marked pulmonary lesions.

    PubMed

    Müller, Joachim; Putora, Paul Martin; Schneider, Tino; Zeisel, Christoph; Brutsche, Martin; Baty, Florent; Markus, Alexander; Kick, Jochen

    2016-09-01

    Radioactive marking can be a valuable extension to minimally invasive surgery. The technique has been clinically applied in procedures involving sentinel lymph nodes, parathyroidectomy as well as interventions in thoracic surgery. Improvements in equipment and techniques allow one to improve the limits. Pulmonary nodules are frequently surgically removed for diagnostic or therapeutic reasons; here video-assisted thoracoscopic surgery (VATS) is the preferred technique. VATS might be impossible with nodules that are small or located deep in the lung. In this study, we examined the clinical application and safety of employing the newly developed handheld single photon emission tomography (handheld SPECT) device in combination with CT-guided radioactive marking of pulmonary nodules. In this pilot study, 10 subjects requiring surgical resection of a pulmonary nodule were included. The technique involved CT-guided marking of the target nodule with a 20-G needle, with subsequent injection of 25-30 MBq (effective: 7-14 MBq) Tc-99m MAA (Macro Albumin Aggregate). Quality control was made with conventional SPECT-CT to confirm the correct localization and exclude possible complications related to the puncture procedure. VATS was subsequently carried out using the handheld SPECT to localize the radioactivity intraoperatively and therefore the target nodule. A 3D virtual image was superimposed on the intraoperative visual image for surgical guidance. In 9 of the 10 subjects, the radioactive application was successfully placed directly in or in the immediate vicinity of the target nodule. The average size of the involved nodules was 9 mm (range 4-15). All successfully marked nodules were subsequently completely excised (R0) using VATS. The procedure was well tolerated. An asymptomatic clinically insignificant pneumothorax occurred in 5 subjects. Two subjects were found to have non-significant discrete haemorrhage in the infiltration canal of the needle. In a single subject, the

  10. Use of neural networks in brain SPECT to diagnose Alzheimer's disease.

    PubMed

    Page, M P; Howard, R J; O'Brien, J T; Buxton-Thomas, M S; Pickering, A D

    1996-02-01

    The usefulness of artificial neural networks in the classification of 99mTc-HMPAO SPECT axial brain scans was investigated in a study group of Alzheimer's disease patients and age-matched normal subjects. The cortical circumferential profiling (CCP) technique was used to extract information regarding patterns of cortical perfusion. Traditional analysis of the CCP data, taken from slices at the level of the basal ganglia, indicated significant perfusion deficits for Alzheimer's disease patients relative to normals, particularly in the left temporo-parietal and left posterior frontal areas of the cortex. The compressed profiles were then used to train a neural-network classifier, the performance of which was compared with that of a number of more traditional statistical (discriminant function) techniques and that of two expert viewers. The optimal classification performance of the neural network (ROC area = 0.91) was better than that of the alternative statistical techniques (max. ROC area = 0.85) and that of the expert viewers (max. ROC area = 0.79). The CCP produces perfusion profiles which are well suited to automated classification methods, particularly those employing neural networks. The technique has the potential for wide application.

  11. Evaluation of quantitative accuracy in CZT-based pre-clinical SPECT for various isotopes

    NASA Astrophysics Data System (ADS)

    Park, S.-J.; Yu, A. R.; Kim, Y.-s.; Kang, W.-S.; Jin, S. S.; Kim, J.-S.; Son, T. J.; Kim, H.-J.

    2015-05-01

    In vivo pre-clinical single-photon emission computed tomography (SPECT) is a valuable tool for functional small animal imaging, but several physical factors, such as scatter radiation, limit the quantitative accuracy of conventional scintillation crystal-based SPECT. Semiconductor detectors such as CZT overcome these deficiencies through superior energy resolution. To our knowledge, little scientific information exists regarding the accuracy of quantitative analysis in CZT-based pre-clinical SPECT systems for different isotopes. The aim of this study was to assess the quantitative accuracy of CZT-based pre-clinical SPECT for four isotopes: 201Tl, 99mTc, 123I, and 111In. The quantitative accuracy of the CZT-based Triumph X-SPECT (Gamma-Medica Ideas, Northridge, CA, U.S.A.) was compared with that of a conventional SPECT using GATE simulation. Quantitative errors due to the attenuation and scatter effects were evaluated for all four isotopes with energy windows of 5%, 10%, and 20%. A spherical source containing the isotope was placed at the center of the air-or-water-filled mouse-sized cylinder phantom. The CZT-based pre-clinical SPECT was more accurate than the conventional SPECT. For example, in the conventional SPECT with an energy window of 10%, scatter effects degraded quantitative accuracy by up to 11.52%, 5.10%, 2.88%, and 1.84% for 201Tl, 99mTc, 123I, and 111In, respectively. However, with the CZT-based pre-clinical SPECT, the degradations were only 9.67%, 5.45%, 2.36%, and 1.24% for 201Tl, 99mTc, 123I, and 111In, respectively. As the energy window was increased, the quantitative errors increased in both SPECT systems. Additionally, the isotopes with lower energy of photon emissions had greater quantitative error. Our results demonstrated that the CZT-based pre-clinical SPECT had lower overall quantitative errors due to reduced scatter and high detection efficiency. Furthermore, the results of this systematic assessment quantifying the accuracy of these SPECT

  12. Automatic estimation of detector radial position for contoured SPECT acquisition using CT images on a SPECT/CT system

    SciTech Connect

    Liu Ruijie Rachel; Erwin, William D.

    2006-08-15

    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 {<=}22.5 cm and led to occasional radius underestimation in the case of object truncation by CT. Two methods incorporating the algorithm were implemented: physical model (PM) and best fit (BF). The PM method computed an offset that produced maximum overlap of calculated and true radii for the phantom scans, and applied that offset as a calculated-to-true radius transformation. For the BF method, the calculated-to-true radius transformation was based upon a linear regression between calculated and true radii. For the PM method, a fixed offset of +2.75 cm provided maximum calculated-to-true radius overlap for the phantom study, which accounted for the camera system's object contour detect sensor surface-to-detector face distance. For the BF method, a linear regression of true versus calculated radius from a reference patient scan was used as a calculated-to-true radius transform. Both methods were applied to ten patient scans. For -970 and -950 HU thresholds, the combined overall average root-mean-square (rms) error

  13. Tc-99m SPECT sestamibi for the measurement of infarct size.

    PubMed

    Gibbons, Raymond J

    2011-01-01

    There are a variety of approaches to assess the efficacy of reperfusion therapy, and myocardial protection, in acute myocardial infarction. This review summarizes the available evidence validating the use of technetium-99m sestamibi single-photon emission computed tomography (SPECT) for this purpose. Multiple lines of evidence have validated its clinical utility. SPECT sestamibi infarct size has been used as an endpoint in multiple randomized clinical trials. A smaller number of clinical trials have used both early and later imaging with SPECT sestamibi to assess myocardium at risk and myocardial salvage. SPECT sestamibi has a number of limitations which must be recognized. Nevertheless, SPECT sestamibi infarct size is a well-validated measurement with a long track record of performance as an endpoint in multicenter, randomized clinical trials.

  14. Experimental studies of SPECT scintimammography with combined cone-beam and parallel-beam collimators

    NASA Astrophysics Data System (ADS)

    Krol, Andrzej; Feiglin, David H.; Gangal, K. R.; Coman, Ioana L.; Salgado, Roberto B.; Lipson, Edward D.; Karczewski, Deborah A.; Thomas, Frank D.

    2003-05-01

    Conventional SPECT Tc-99m sestamibi scintimammography (STSM) has limited clinical utility due to fairly low radiopharmaceutical uptake in the breast tissue as compared to the heart and the liver. We investigated the use of a cone-beam collimator (CBC) to STSM. Each detector on a multi-headed gamma camera can be equipped with parallel-beam (PBC) or cone-beam collimators (CBC). PBC can provide truncation-free SPECT projection sets, while CBC offers increased sensitivity in a limited field-of-view (FOV). Combined PBC and CBC SPECT ddata acquisition may provide improved lesion contrast and overall better imaging performance within CBC FOV with significantly reduced truncation artifacts in the reconstructed images. In this paper we evaluate the combined CBC&PBC SPECT method using a limited number of confirmed breast cancer patients and female chest phantoms with simulated breast lesions. We envision the combined CBC&PBC SPECT as a useful clinical tool in scintimammography.

  15. A Vector Uniform Cramer-Rao Bound for SPECT System Design

    PubMed Central

    Meng, Ling-Jian; Li, Nan

    2016-01-01

    In this paper, we present the use of modified uniform Cramer-Rao type bounds (MUCRB) for the design of single photon emission tomography (SPECT) systems. The MUCRB is the lowest attainable total variance using any estimator of an unknown vector parameter, whose mean gradient matrix satisfies a given constraint. Since the mean gradient is closely related to local impulse function, the MUCRB approach can be used to evaluate the fundamental tradeoffs between spatial resolution and variance that are achievable with a given SPECT system design. As a possible application, this approach allows one to compare different SPECT system designs based on the optimum average resolution-variance tradeoffs that can be achieved across multiple control-points inside a region-of-interest. The formulation of the MUCRB allows detailed modelling of physical aspects of practical SPECT systems and requests only a modest computation load. It can be used as an analytical performance index for comparing different SPECT system or aperture designs.

  16. A noninvasive dose estimation system for clinical BNCT based on PG-SPECT--conceptual study and fundamental experiments using HPGe and CdTe semiconductor detectors.

    PubMed

    Kobayashi, T; Sakurai, Y; Ishikawa, M

    2000-09-01

    A noninvasive method for measuring the absorbed dose distribution during the administration of clinical boron neutron capture therapy (BNCT) using an online three-dimensional (3D) imaging system is presented. This system is designed to provide more accurate information for treatment planning and dosimetry. The single-photon emission computed tomography (SPECT) technique is combined with prompt gamma-ray analysis (PGA) to provide an ideal dose estimation system for BNCT. This system is termed PG-SPECT. The fundamental feasibility of the PG-SPECT system for BNCT is confirmed under the following conditions: (1) a voxel size of 1 x 1 x 1 cm3, comparable to the spatial resolution of our standard dosimetric technique using gold wire activation, where data are available for every 5-10 mm of wire length; (2) a reaction rate of 10B(n,alpha)7Li within the measurement volume is greater than 1.1 x l0(6) interactions/cm3/s, corresponding to a thermal neutron flux of 5 x 10(8) n/cm2/s and a 10B concentration of greater than 10 ppm for the deepest part of the tumor volume under typical BNCT clinical conditions; (3) statistical uncertainty of the count rate for 10B(n,alpha)7Li prompt gamma rays is 10% or less. The desirable characteristics of a detector for the PG-SPECT system were determined by basic experiments using both HPGe and CdTe semiconductor detectors. The CdTe semiconductor detector has the greatest potential for this system because of its compactness and simplicity of maintenance.

  17. Comparative evaluation of MRS and SPECT in prognostication of patients with mild to moderate head injury.

    PubMed

    Dhandapani, Sivashanmugam; Sharma, Anurag; Sharma, Karamchand; Das, Lakshman

    2014-05-01

    Magnetic resonance spectroscopy (MRS) and single-photon emission computed tomography (SPECT) have only been individually studied in patients with head injury. This study aimed to comparatively assess both in patients with mild to moderate head injury. Patients with a Glasgow Coma Scale (GCS) score of 9-14 who underwent MRS and/or SPECT were evaluated in relation to various clinical factors and neurological outcome at 3months. There were 56 SPECT (Tc99m-ethylcysteinate dimer [ECD]) studies and 41 single voxel proton MRS performed in 53 patients, with 41 patients having both. Of the 41 who underwent MRS, 13 had a lower N-acetyl-aspartate/creatine (NAA/Cr) ratio, 14 had a higher choline (Cho)/Cr ratio, 19 were normal, and nine had bilateral MRS abnormalities. Of the 56 who underwent SPECT, 22 and 19 had severe and moderate hypoperfusion, respectively. Among those in Traumatic Coma Data Bank CT scan category 1 and 2, 50% had MRS abnormalities, whereas 64% had SPECT hypoperfusion, suggesting greater incremental validity of SPECT over MRS. In univariate analyses, GCS, moderate/severe hypoperfusion and bilateral SPECT changes were found to have significant association with unfavorable outcome (odds ratio 13.2, 15.9, and 4.4, and p values <0.01, 0.01, and 0.05, respectively). Patients with lower NAA/Cr ratio in MRS had more unfavorable outcomes, however this was not significant. In multivariate analysis employing binary logistic regression, GCS and severe hypoperfusion on SPECT were noted to have significant association with unfavorable outcome, independent of age, CT scan category, and MRS abnormalities (p values=0.02 and 0.04, respectively). To conclude, ECD-SPECT seems to have greater sensitivity, incremental validity and prognostic value than single voxel proton MRS in select patients with head injury, with only severe hypoperfusion in SPECT significantly associated with unfavorable outcome independent of other confounding factors.

  18. The efficacy of (18)F-FDG PET/CT and (67)Ga SPECT/CT in diagnosing fever of unknown origin.

    PubMed

    Hung, Bor-Tau; Wang, Pei-Wen; Su, Yu-Jih; Huang, Wen-Chi; Chang, Yen-Hsiang; Huang, Shu-Hua; Chang, Chiung-Chih

    2017-09-01

    Fever of unknown origin (FUO) is a diagnostic challenge. This study aimed to assess the efficacy of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) and gallium-67 single-photon emission computed tomography/computed tomography ((67)Ga SPECT/CT) in diagnosing FUO. A total of 68 patients with FUO underwent (18)F-FDG PET/CT and (67)Ga SPECT/CT from January 2013 through May 2016. Images were read independently. The imaging results were compared with the final diagnosis and categorized as helpful for diagnosis or non-contributory to diagnosis in the clinical setting. Associations between categorical variables were evaluated with the chi-square test or Fisher's exact test. Ten of the 68 patients were excluded. An infectious underlying disease was found in 23 patients. A malignant disorder was the cause of FUO in 10 patients. Non-infectious inflammatory disease was found in 11 patients. Adrenal insufficiency was the cause of FUO in two patients. The cause of FUO was not found for 12 patients. A high false-positive rate of 44% (7/16) was observed for (18)F-FDG PET/CT, while a high false-negative rate of 55% (23/42) was observed for (67)Ga SPECT/CT. (18)F-FDG PET/CT studies depicted all (67)Ga-avid lesions. The sensitivity (79% vs. 45%) and clinical contribution (72% vs. 55%) of (18)F-FDG PET/CT in diagnosing FUO were significantly higher than those of (67)Ga SPECT/CT (p<0.05). On the basis of this study, the diagnostic performance of (18)F-FDG PET/CT is superior to (67)Ga SPECT/CT in the work-up of patients with FUO. With its rapid results and superior sensitivity, (18)F-FDG PET/CT may replace (67)Ga SPECT/CT where this technique is available. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  19. Post-reconstruction non-local means filtering methods using CT side information for quantitative SPECT.

    PubMed

    Chun, Se Young; Fessler, Jeffrey A; Dewaraja, Yuni K

    2013-09-07

    Quantitative SPECT techniques are important for many applications including internal emitter therapy dosimetry where accurate estimation of total target activity and activity distribution within targets are both potentially important for dose–response evaluations. We investigated non-local means (NLM) post-reconstruction filtering for accurate I-131 SPECT estimation of both total target activity and the 3D activity distribution. We first investigated activity estimation versus number of ordered-subsets expectation–maximization (OSEM) iterations. We performed simulations using the XCAT phantom with tumors containing a uniform and a non-uniform activity distribution, and measured the recovery coefficient (RC) and the root mean squared error (RMSE) to quantify total target activity and activity distribution, respectively. We observed that using more OSEM iterations is essential for accurate estimation of RC, but may or may not improve RMSE. We then investigated various post-reconstruction filtering methods to suppress noise at high iteration while preserving image details so that both RC and RMSE can be improved. Recently, NLM filtering methods have shown promising results for noise reduction. Moreover, NLM methods using high-quality side information can improve image quality further. We investigated several NLM methods with and without CT side information for I-131 SPECT imaging and compared them to conventional Gaussian filtering and to unfiltered methods. We studied four different ways of incorporating CT information in the NLM methods: two known (NLM CT-B and NLM CT-M) and two newly considered (NLM CT-S and NLM CT-H). We also evaluated the robustness of NLM filtering using CT information to erroneous CT. NLM CT-S and NLM CT-H yielded comparable RC values to unfiltered images while substantially reducing RMSE. NLM CT-S achieved −2.7 to 2.6% increase of RC compared to no filtering and NLM CT-H yielded up to 6% decrease in RC while other methods yielded lower

  20. Post-reconstruction non-local means filtering methods using CT side information for quantitative SPECT

    NASA Astrophysics Data System (ADS)

    Chun, Se Young; Fessler, Jeffrey A.; Dewaraja, Yuni K.

    2013-09-01

    Quantitative SPECT techniques are important for many applications including internal emitter therapy dosimetry where accurate estimation of total target activity and activity distribution within targets are both potentially important for dose-response evaluations. We investigated non-local means (NLM) post-reconstruction filtering for accurate I-131 SPECT estimation of both total target activity and the 3D activity distribution. We first investigated activity estimation versus number of ordered-subsets expectation-maximization (OSEM) iterations. We performed simulations using the XCAT phantom with tumors containing a uniform and a non-uniform activity distribution, and measured the recovery coefficient (RC) and the root mean squared error (RMSE) to quantify total target activity and activity distribution, respectively. We observed that using more OSEM iterations is essential for accurate estimation of RC, but may or may not improve RMSE. We then investigated various post-reconstruction filtering methods to suppress noise at high iteration while preserving image details so that both RC and RMSE can be improved. Recently, NLM filtering methods have shown promising results for noise reduction. Moreover, NLM methods using high-quality side information can improve image quality further. We investigated several NLM methods with and without CT side information for I-131 SPECT imaging and compared them to conventional Gaussian filtering and to unfiltered methods. We studied four different ways of incorporating CT information in the NLM methods: two known (NLM CT-B and NLM CT-M) and two newly considered (NLM CT-S and NLM CT-H). We also evaluated the robustness of NLM filtering using CT information to erroneous CT. NLM CT-S and NLM CT-H yielded comparable RC values to unfiltered images while substantially reducing RMSE. NLM CT-S achieved -2.7 to 2.6% increase of RC compared to no filtering and NLM CT-H yielded up to 6% decrease in RC while other methods yielded lower RCs

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

    SciTech Connect

    Pourmoghaddas, Amir Wells, R. Glenn

    2016-01-15

    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 their 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, GE

  2. A multipinhole small animal SPECT system with submillimeter spatial resolution

    SciTech Connect

    Funk, Tobias; Despres, Philippe; Barber, William C.; Shah, Kanai S.; Hasegawa, Bruce H.

    2006-05-15

    Single photon emission computed tomography (SPECT) is an important technology for molecular imaging studies of small animals. In this arena, there is an increasing demand for high performance imaging systems that offer improved spatial resolution and detection efficiency. We have designed a multipinhole small animal imaging system based on position sensitive avalanche photodiode (PSAPD) detectors with the goal of submillimeter spatial resolution and high detection efficiency, which will allow us to minimize the radiation dose to the animal and to shorten the time needed for the imaging study. Our design will use 8x24 mm{sup 2} PSAPD detector modules coupled to thallium-doped cesium iodide [CsI(Tl)] scintillators, which can achieve an intrinsic spatial resolution of 0.5 mm at 140 keV. These detectors will be arranged in rings of 24 modules each; the animal is positioned in the center of the 9 stationary detector rings which capture projection data from the animal with a cylindrical tungsten multipinhole collimator. The animal is supported on a bed which can be rocked about the central axis to increase angular sampling of the object. In contrast to conventional SPECT pinhole systems, in our design each pinhole views only a portion of the object. However, the ensemble of projection data from all of the multipinhole detectors provide angular sampling that is sufficient to reconstruct tomographic data from the object. The performance of this multipinhole PSAPD imaging system was simulated using a ray tracing program that models the appropriate point spread functions and then was compared against the performance of a dual-headed pinhole SPECT system. The detection efficiency of both systems was simulated and projection data of a hot rod phantom were generated and reconstructed to assess spatial resolution. Appropriate Poisson noise was added to the data to simulate an acquisition time of 15 min and an activity of 18.5 MBq distributed in the phantom. Both sets of data

  3. 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

  4. 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.

  5. Multipinhole collimator with 20 apertures for a brain SPECT application

    SciTech Connect

    Lee, Tzu-Cheng; Ellin, Justin R.; Shrestha, Uttam; Seo, Youngho; Huang, Qiu; Gullberg, Grant T.

    2014-11-01

    Purpose: Several new technologies for single photon emission computed tomography (SPECT) instrumentation with parallel-hole collimation have been proposed to improve detector sensitivity and signal collection efficiency. Benefits from improved signal efficiency include shorter acquisition times and lower dose requirements. In this paper, the authors show a possibility of over an order of magnitude enhancement in photon detection efficiency (from 7.6 × 10{sup −5} to 1.6 × 10{sup −3}) for dopamine transporter (DaT) imaging of the striatum over the conventional SPECT parallel-hole collimators by use of custom-designed 20 multipinhole (20-MPH) collimators with apertures of 0.75 cm diameter. Methods: Quantifying specific binding ratio (SBR) of {sup 123}I-ioflupane or {sup 123}I-iometopane’s signal at the striatal region is a common brain imaging method to confirm the diagnosis of the Parkinson’s disease. The authors performed imaging of a striatal phantom filled with aqueous solution of I-123 and compared camera recovery ratios of SBR acquired between low-energy high-resolution (LEHR) parallel-hole collimators and 20-MPH collimators. Results: With only two-thirds of total acquisition time (20 min against 30 min), a comparable camera recovery ratio of SBR was achieved using 20-MPH collimators in comparison to that from the LEHR collimator study. Conclusions: Their systematic analyses showed that the 20-MPH collimator could be a promising alternative for the DaT SPECT imaging for brain over the traditional LEHR collimator, which could give both shorter scan time and improved diagnostic accuracy.

  6. Impact of reconstruction parameters on quantitative I-131 SPECT

    NASA Astrophysics Data System (ADS)

    van Gils, C. A. J.; Beijst, C.; van Rooij, R.; de Jong, H. W. A. M.

    2016-07-01

    Radioiodine therapy using I-131 is widely used for treatment of thyroid disease or neuroendocrine tumors. Monitoring treatment by accurate dosimetry requires quantitative imaging. The high energy photons however render quantitative SPECT reconstruction challenging, potentially requiring accurate correction for scatter and collimator effects. The goal of this work is to assess the effectiveness of various correction methods on these effects using phantom studies. A SPECT/CT acquisition of the NEMA IEC body phantom was performed. Images were reconstructed using the following parameters: (1) without scatter correction, (2) with triple energy window (TEW) scatter correction and (3) with Monte Carlo-based scatter correction. For modelling the collimator-detector response (CDR), both (a) geometric Gaussian CDRs as well as (b) Monte Carlo simulated CDRs were compared. Quantitative accuracy, contrast to noise ratios and recovery coefficients were calculated, as well as the background variability and the residual count error in the lung insert. The Monte Carlo scatter corrected reconstruction method was shown to be intrinsically quantitative, requiring no experimentally acquired calibration factor. It resulted in a more accurate quantification of the background compartment activity density compared with TEW or no scatter correction. The quantification error relative to a dose calibrator derived measurement was found to be  <1%,-26% and 33%, respectively. The adverse effects of partial volume were significantly smaller with the Monte Carlo simulated CDR correction compared with geometric Gaussian or no CDR modelling. Scatter correction showed a small effect on quantification of small volumes. When using a weighting factor, TEW correction was comparable to Monte Carlo reconstruction in all measured parameters, although this approach is clinically impractical since this factor may be patient dependent. Monte Carlo based scatter correction including accurately simulated CDR

  7. Impact of reconstruction parameters on quantitative I-131 SPECT.

    PubMed

    van Gils, C A J; Beijst, C; van Rooij, R; de Jong, H W A M

    2016-07-21

    Radioiodine therapy using I-131 is widely used for treatment of thyroid disease or neuroendocrine tumors. Monitoring treatment by accurate dosimetry requires quantitative imaging. The high energy photons however render quantitative SPECT reconstruction challenging, potentially requiring accurate correction for scatter and collimator effects. The goal of this work is to assess the effectiveness of various correction methods on these effects using phantom studies. A SPECT/CT acquisition of the NEMA IEC body phantom was performed. Images were reconstructed using the following parameters: (1) without scatter correction, (2) with triple energy window (TEW) scatter correction and (3) with Monte Carlo-based scatter correction. For modelling the collimator-detector response (CDR), both (a) geometric Gaussian CDRs as well as (b) Monte Carlo simulated CDRs were compared. Quantitative accuracy, contrast to noise ratios and recovery coefficients were calculated, as well as the background variability and the residual count error in the lung insert. The Monte Carlo scatter corrected reconstruction method was shown to be intrinsically quantitative, requiring no experimentally acquired calibration factor. It resulted in a more accurate quantification of the background compartment activity density compared with TEW or no scatter correction. The quantification error relative to a dose calibrator derived measurement was found to be  <1%,-26% and 33%, respectively. The adverse effects of partial volume were significantly smaller with the Monte Carlo simulated CDR correction compared with geometric Gaussian or no CDR modelling. Scatter correction showed a small effect on quantification of small volumes. When using a weighting factor, TEW correction was comparable to Monte Carlo reconstruction in all measured parameters, although this approach is clinically impractical since this factor may be patient dependent. Monte Carlo based scatter correction including accurately simulated CDR

  8. Impact of subcortical white matter lesions on dopamine transporter SPECT.

    PubMed

    Funke, Elisabeth; Kupsch, Andreas; Buchert, Ralph; Brenner, Winfried; Plotkin, Michail

    2013-07-01

    Subcortical arteriosclerotic encephalopathy (SAE) can affect the nigrostriatal system and presumably cause vascular parkinsonism (VP). However, in patients with SAE, the differentiation of VP from idiopathic Parkinson's disease (IPS) is challenging. The aim of the present study was to examine the striatal dopamine transporter (DAT) density in patients with parkinsonism and SAE. Fifteen consecutive patients with parkinsonian symptoms displayed SAE, as detected by magnetic resonance imaging (MRI). Fifteen retrospectively chosen, matched patients with diagnosis of IPS without any abnormalities in MRI served as a reference group. DAT SPECT was performed using the tracer ¹²³I-FP-CIT. Scans were acquired on a triple-head SPECT system (Multispect 3, Siemens) and analysed using the investigator-independent BRASS™ software (HERMES). In the SAE group, a DAT deficit was observed in 9/15 patients. In contrast, all patients from the IPS group showed a reduced DAT binding (p = 0.008). The specific binding ratios (BR) of putamen contralateral to the side of the more affected limb versus occipital lobe were in trend higher in patients with SAE versus patients in the IPS-group (p = 0.053). Indices for putaminal asymmetry (p = 0.036) and asymmetry caudate-to-putamen (p = 0.026) as well as the ratio caudate-to-putamen (p = 0.048) were significantly higher in IPS patients having no SAE. DAT deficit was less pronounced in patients with SAE and parkinsonism than in patients with IPS without any abnormalities in the MRI. A potential role of DAT SPECT in the differential diagnosis of VP and IPS requires more assessments within prospective studies.

  9. High Sensitivity SPECT for Small Animals and Plants

    SciTech Connect

    Mitchell, Gregory S.

    2015-02-28

    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.

  10. SPECT Imaging to Evaluate Post Traumatic Stress Disorder

    DTIC Science & Technology

    2011-02-01

    neuroinflammation. J Nucl Med, 2007. 48(4): p. 573-81. 66. Seibyl, J.P., E. Wallace, E.O. Smith, M. Stabin, R.M. Baldwin, S. Zoghbi, Y. Zea -Ponce, Y. Gao... Zea -Ponce, C. Olson, D.S. Charney, and et al., Human biodistribution and dosimetry of the SPECT benzodiazepine receptor radioligand iodine-123...J Nucl Med, 1997. 24(11): p. 1422-5. 23 70. van Dyck, C.H., J.P. Seibyl, J.B. Stubbs, S. Zoghbi, G. Wisniewski, R.M. Baldwin, Y. Zea -Ponce, D.S

  11. Dopamine transporter SPECT in patients with mitochondrial disorders

    PubMed Central

    Minnerop, M; Kornblum, C; Joe, A; Tatsch, K; Kunz, W; Klockgether, T; Wullner, U; Reinhardt, M

    2005-01-01

    Objective : To investigate the dopaminergic system in patients with known mitochondrial disorders and complex I deficiency. Methods: Dopamine transporter density was studied in 10 female patients with mitochondrial complex I deficiency by 123I-FP-CIT (N-ß-fluoropropyl-2ß-carbomethyl-3ß-(4-iodophenyl)-nortropane) SPECT. Results: No differences in 123I-FP-CIT striatal binding ratios were observed and no correlation of the degree of complex I deficiency and striatal binding ratios could be detected. Conclusions: These data argue against the possibility that mitochondrial complex I deficiency by itself is sufficient to elicit dopaminergic cell loss. PMID:15608010

  12. Robin Hood caught in Wonderland: brain SPECT findings.

    PubMed

    Morland, David; Wolff, Valérie; Dietemann, Jean-Louis; Marescaux, Christian; Namer, Izzie Jacques

    2013-12-01

    We present the case of a 53-year-old woman presenting several episodes of body image distortions, ground deformation illusions, and problems assessing distance in the orthostatic position corresponding to the Alice in Wonderland syndrome. No symptoms were reported when sitting or lying down. She had uncontrolled hypertension, hyperglycemia, hypercholesterolemia, and a history of head trauma. Her condition had been diagnosed with left internal carotid artery dissection 2 years earlier. Brain SPECT with 99mTc-ECD performed after i.v. injection of the radiotracer in supine and in standing positions showed hypoperfusion in the healthy contralateral frontoparietal operculum (Robin Hood syndrome), deteriorating when standing up.

  13. Detection of breast cancer microcalcification using 99mTc-MDP SPECT or Osteosense 750EX FMT imaging

    PubMed Central

    Felix, Dayo D.; Gore, John C.; Yankeelov, Thomas E.; Peterson, Todd E.; Barnes, Stephanie; Whisenant, Jennifer; Weis, Jared; Shoukouhi, Sepideh; Virostko, John; Nickels, Michael; McIntyre, J. Oliver; Sanders, Melinda; Abramson, Vandana; Tantawy, Mohammed N.

    2015-01-01

    Background In previous work, we demonstrated the presence of hydroxyapetite (type II microcalcification), HAP, in triple negative MDA-MB-231 breast cancer cells. We used 18F-NaF to detect these types of cancers in mouse models as the free fluorine, 18F−, binds to HAP similar to bone uptake. In this work, we investigate other bone targeting agents and techniques including 99mTc-MDP SPECT and Osteosense 750EX FMT imaging as alternatives for breast cancer diagnosis via targeting HAP within the tumor microenvironment. Methods Thirteen mice were injected subcutaneously in the right flank with 106 MDA-MB-231 cells. When the tumor size reached ~0.6 cm3, mice (n = 9) were injected with ~37 MBq of 99mTc-MDP intravenously and then imaged one hour later in a NanoSPECT/CT or injected intravenously with 4 nmol/g of Osetosense 750EX and imaged 24 hours later in an FMT (n = 4). The imaging probe concentration in the tumor was compared to that of muscle. Following SPECT imaging, the tumors were harvested, sectioned into 10 µm slices, and underwent autoradiography or von Kossa staining to correlate 99mTc-MDP binding with HAP distribution within the tumor. The SPECT images were normalized to the injected dose and regions-of-interest (ROIs) were drawn around bone, tumor, and muscle to obtain the radiotracer concentration in these regions in units of percent injected dose per unit volume. ROIs were drawn around bone and tumor in the FMT images as no FMT signal was observed in normal muscle. Results Uptake of 99mTc-MDP was observed in the bone and tumor with little or no uptake in the muscle with concentrations of 11.34 ± 1.46 (mean ± SD), 2.22 ± 0.95, and 0.05 ± 0.04 %ID/cc, respectively. Uptake of Osteosense 750EX was also observed in the bone and tumor with concentrations of 0.35 ± 0.07 (mean ± SD) and 0.04 ± 0.01 picomoles, respectively. No FMT signal was observed in the normal muscle. There was no significant difference in the bone-to-tumor ratio between the two

  14. Patterns of bone tracer uptake on SPECT-CT in symptomatic and asymptomatic patients with primary total hip arthroplasty.

    PubMed

    Schweizer, Thierry; Schiapparelli, Filippo-Franco; Rotigliano, Niccolo; Rasch, Helmut; Amsler, Felix; Hirschmann, Michael T

    2017-09-19

    patients of group S with a BTU ≥ 3.1. With regards to the fixation technique, only the BTU at the level 6 in group S presented a significant difference between cemented and uncemented stems (p < 0.05). Higher BTU levels significantly correlated with symptoms, but a normal BTU could not exclude a specific pathology after THA. A threshold of BTU in SPECT/CT was identified to distinguish between symptomatic and asymptomatic patients after THA.

  15. High-Resolution Anamorphic SPECT Imaging

    PubMed Central

    Durko, Heather L.; Barrett, Harrison H.; Furenlid, Lars R.

    2015-01-01

    We have developed a gamma-ray imaging system that combines a high-resolution silicon detector with two sets of movable, half-keel-edged copper-tungsten blades configured as crossed slits. These apertures can be positioned independently between the object and detector, producing an anamorphic image in which the axial and transaxial magnifications are not constrained to be equal. The detector is a 60 mm × 60 mm, one-millimeter-thick, one-megapixel silicon double-sided strip detector with a strip pitch of 59 μm. The flexible nature of this system allows the application of adaptive imaging techniques. We present system details; calibration, acquisition, and reconstruction methods; and imaging results. PMID:26160983

  16. Reproducibility of area at risk assessment in acute myocardial infarction by T1- and T2-mapping sequences in cardiac magnetic resonance imaging in comparison to Tc99m-sestamibi SPECT.

    PubMed

    Langhans, Birgit; Nadjiri, Jonathan; Jähnichen, Christin; Kastrati, Adnan; Martinoff, Stefan; Hadamitzky, Martin

    2014-10-01

    Area at risk (AAR) is an important parameter for the assessment of the salvage area after revascularization in acute myocardial infarction (AMI). By combining AAR assessment by T2-weighted imaging and scar quantification by late gadolinium enhancement imaging cardiovascular magnetic resonance (CMR) offers a promising alternative to the "classical" modality of Tc99m-sestamibi single photon emission tomography (SPECT). Current T2 weighted sequences for edema imaging in CMR are limited by low contrast to noise ratios and motion artifacts. During the last years novel CMR imaging techniques for quantification of acute myocardial injury, particularly the T1-mapping and T2-mapping, have attracted rising attention. But no direct comparison between the different sequences in the setting of AMI or a validation against SPECT has been reported so far. We analyzed 14 patients undergoing primary coronary revascularization in AMI in whom both a pre-intervention Tc99m-sestamibi-SPECT and CMR imaging at a median of 3.4 (interquartile range 3.3-3.6) days after the acute event were performed. Size of AAR was measured by three different non-contrast CMR techniques on corresponding short axis slices: T2-weighted, fat-suppressed turbospin echo sequence (TSE), T2-mapping from T2-prepared balanced steady state free precession sequences (T2-MAP) and T1-mapping from modified look locker inversion recovery (MOLLI) sequences. For each CMR sequence, the AAR was quantified by appropriate methods (absolute values for mapping sequences, comparison with remote myocardium for other sequences) and correlated with Tc99m-sestamibi-SPECT. All measurements were performed on a 1.5 Tesla scanner. The size of the AAR assessed by CMR was 28.7 ± 20.9 % of left ventricular myocardial volume (%LV) for TSE, 45.8 ± 16.6 %LV for T2-MAP, and 40.1 ± 14.4 %LV for MOLLI. AAR assessed by SPECT measured 41.6 ± 20.7 %LV. Correlation analysis revealed best correlation with SPECT for T2-MAP at a T2-threshold of 60 ms

  17. Quantification of myocardial blood flow using (201)Tl SPECT and population-based input function.

    PubMed

    Koshino, Kazuhiro; Fukushima, Kazuhito; Fukumoto, Masaji; Hori, Yuki; Moriguchi, Tetsuaki; Zeniya, Tsutomu; Nishimura, Yoshihiro; Kiso, Keisuke; Iida, Hidehiro

    2014-11-01

    Thallium-201 ((201)Tl) single photon emission computed tomography (SPECT) is an important tool in the diagnosis of ischemic heart disease. Absolute quantification of myocardial blood flow (MBF) has the potential to provide more useful information on myocardial perfusion than semi-quantitative assessments. This study aimed to validate the quantification of MBF using (201)Tl cardiac SPECT based on a population-averaged input function (STD-IF) and one-point blood sample technique. (201)Tl emission and computed tomography (CT)-based attenuation scans were performed on 11 healthy volunteers at rest using a SPECT/CT scanner. Individual input functions (IND-IFs) during the emission scans were based on arterial blood samples. The STD-IF technique was validated as follows: (1) optimal time to calibrate a STD-IF was determined to minimize differences between the calibrated STD-IF and the IND-IFs. (2) Tissue time-activity curves (TTACs) were generated based on a single-tissue compartment model for MBFtrue = 0.5, 1.0, 1.5, and 2.0 mL/min/g, a constant distribution volume of 45 mL/mL, and IND-IFs. The pseudo STD-IF for each subject was generated using the leave-one-out technique. Using the optimal calibration time and the pseudo STD-IFs, MBF values were estimated on the TTACs with an autoradiography method. Optimal mid-scan time (MST) with a fixed duration of 20 min was determined to minimize intersubject variation in estimated MBF errors, and (3) Global and regional MBF values estimated with pseudo STD-IFs were compared to those with IND-IFs using the optimal calibration time and MST. The optimal calibration time and MST were both 20 min after (201)Tl injection. Global MBF determined using both IND-IFs and pseudo STD-IF showed significant correlations with rate-pressure products, R (2) = 0.645; p < 0.01 and R (2) = 0.303; p < 0.05, respectively. The mean percent error in regional MBF using pseudo STD-IFs was 0.69 ± 7.80 % (-12.80 to 14.25 %). No significant

  18. Computer-assisted superimposition of magnetic resonance and high-resolution technetium-99m-HMPAO and thallium-201 SPECT images of the brain

    SciTech Connect

    Holman, B.L.; Zimmerman, R.E.; Johnson, K.A.; Carvalho, P.A.; Schwartz, R.B.; Loeffler, J.S.; Alexander, E.; Pelizzari, C.A.; Chen, G.T. )

    1991-08-01

    A method for registering three-dimensional CT, MR, and PET data sets that require no special patient immobilization or other precise positioning measures was adapted to high-resolution SPECT and MRI and was applied in 14 subjects (five normal volunteers, four patients with dementia (Alzheimer's disease), two patients with recurrent glioblastoma, and three patients with focal lesions (stroke, arachnoid cyst and head trauma)). T2-weighted axial magnetic resonance images and transaxial 99mTc-HMPAO and 201Tl images acquired with an annular gamma camera were merged using an objective registration (translation, rotation and rescaling) program. In the normal subjects and patients with dementia and focal lesions, focal areas of high uptake corresponded to gray matter structures. Focal lesions observed on MRI corresponded to perfusion defects on SPECT. In the patients who had undergone surgical resection of glioblastoma followed by interstitial brachytherapy, increased 201Tl corresponding to recurrent tumor could be localized from the superimposed images. The method was evaluated by measuring the residuals in all subjects and translational errors due to superimposition of deep structures in the 12 subjects with normal thalamic anatomy and 99mTc-HMPAO uptake. This method for superimposing magnetic resonance and high-resolution SPECT images of the brain is a useful technique for correlating regional function with brain anatomy.

  19. 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 uniquenessmore » of 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

  20. Spatial resolution is dependent on image content for SPECT with iterative reconstruction incorporating distance dependent resolution (DDR) correction.

    PubMed

    Badger, Daniel; Barnden, Leighton

    2014-09-01

    The aim of this study is to determine the dependence of single photon emission computed tomography (SPECT) spatial resolution on the content of images for iterative reconstruction with distance dependent resolution (DDR) correction. An experiment was performed using a perturbation technique to measure change in resolution of line sources in simple and complex images with iterative reconstruction with increasing iteration. Projections of the line sources were reconstructed alone and again after the addition of projections of a uniform flood or a complex phantom. An alternative experiment used images of a realistic brain phantom and evaluated an effective spatial resolution by matching the images to the digital version of the phantom convolved with 3D Gaussian kernels. The experiments were performed using ordered subset expectation maximisation iterative reconstruction with and without the use of DDR correction. The results show a significant difference in reconstructed resolution between images of line sources depending on the content of the added image. The full width at half maximum of images of a line source reconstructed using DDR correction increased by 20-30 % when the added image was complex. Without DDR this difference was much smaller and disappeared with increasing iteration. Reported SPECT resolution should be taken as indicative only with regard to clinical imaging if the measurement is made using a point or line source alone and an iterative reconstruction algorithm is used.

  1. 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.

  2. 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

  3. SPECT, MRI and cognitive functions in multiple sclerosis.

    PubMed Central

    Pozzilli, C; Passafiume, D; Bernardi, S; Pantano, P; Incoccia, C; Bastianello, S; Bozzao, L; Lenzi, G L; Fieschi, C

    1991-01-01

    Seventeen patients with relapsing remitting multiple sclerosis (MS) and mild physical disability had neuropsychological testing, magnetic resonance imaging (MRI) and single photon emission computerised tomography (SPECT) using technetium 99m (99mTc) hexamethyl-propyleneamine oxime (HMPAO). Performance in verbal fluency, naming and memory testing appeared to be impaired in MS patients compared with 17 age-sex and education matched normal controls. Weighted periventricular and confluent lesion scores and the width of the third ventricle, proved to be the most sensitive MRI measures in differentiating more cognitively impaired patients from those who were relatively unimpaired. Ratios of regional to whole brain activity, measured by SPECT, showed significant reduction in the frontal lobes and in the left temporal lobe of MS patients. A relationship was found between left temporal abnormality in 99mTc-HMPAO uptake and deficit in verbal fluency and verbal memory. Finally, asymmetrical lobar activity indicated a predominant left rather than right temporo-parietal involvement. PMID:2019835

  4. Radiotracers for PET and SPECT studies of neurotransmitter systems

    SciTech Connect

    Fowler, J.S.

    1991-01-01

    The study of neurotransmitter systems is one of the major thrusts in emission tomography today. The current generation of Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) radiotracers examines neurotransmitter properties from a number of different perspectives including their pre and post synaptic sites and the activity of the enzymes which regulate their concentration. Although the dopamine system has been the most extensively investigated, other neurotransmitter systems including the acetylcholine muscarine, serotonin, benzodiazepine, opiate, NMDA and others are also under intensive development. Enzymes involved in the synthesis and regulation of neurotransmitter concentration, for example monoamine oxidase and amino acid decarboxylase has also been probed in vivo. Medical applications range from the study of normal function and the characterization of neurotransmitter activity in neurological and psychiatric diseases and in heart disease and cancer to the study of the binding of therapeutic drugs and substances of abuse. This chapter will provide an overview of the current generation of radiotracers for PET and SPECT studies of neurotransmitter systems including radiotracer design, synthesis localization mechanisms and applications in emission tomography. 60 refs., 1 tab.

  5. Development of PET and SPECT Probes for Glutamate Receptors

    PubMed Central

    Nakayama, Morio

    2015-01-01

    l-Glutamate and its receptors (GluRs) play a key role in excitatory neurotransmission within the mammalian central nervous system (CNS). Impaired regulation of GluRs has also been implicated in various neurological disorders. GluRs are classified into two major groups: ionotropic GluRs (iGluRs), which are ligand-gated ion channels, and metabotropic GluRs (mGluRs), which are coupled to heterotrimeric guanosine nucleotide binding proteins (G-proteins). Positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging of GluRs could provide a novel view of CNS function and of a range of brain disorders, potentially leading to the development of new drug therapies. Although no satisfactory imaging agents have yet been developed for iGluRs, several PET ligands for mGluRs have been successfully employed in clinical studies. This paper reviews current progress towards the development of PET and SPECT probes for GluRs. PMID:25874256

  6. Brain SPECT findings of anosognosia in Alzheimer's disease.

    PubMed

    Sedaghat, Fereshteh; Dedousi, Eleni; Baloyannis, Ioannis; Tegos, Thomas; Costa, Vasiliki; Dimitriadis, Athanasios S; Baloyannis, Stavros J

    2010-01-01

    Anosognosia is a common symptom of dementia. The aim of this study was to evaluate the contribution of different regions of the brain to anosognosia in Alzheimer's disease (AD) brains using single photon emission computed tomography (SPECT). Forty-two patients with AD were included in this study. After clinical interviews with the patients and their relatives, the patients were divided into two groups: Anosognosia and No-anosognosia. The patients were studied regarding the severity of dementia. They underwent SPECT with HMPAO and regional cerebral blood flow (rCBF) was measured. Regional CBF significantly differed between Anosognosia and No-anosognosia groups in right prefrontal (P < or = 0.02), right inferior parietal (P < or = 0.00), and right (P < or = 0.01) and left (P < or = 0.01) medial temporal cortex. There was a significant correlation between the severity of dementia and rCBF in medial temporal regions. When comparisons were made between mild and moderate stages separately, the 'right inferior parietal region' was the common region which showed hypoperfusion in both anosognosia subgroups. We conclude that anosognosia may be a reflection of functional impairment in right prefrontal, right frontal and especially right inferior parietal regions in AD.

  7. SPECT reconstruction using DCT-induced tight framelet regularization

    NASA Astrophysics Data System (ADS)

    Zhang, Jiahan; Li, Si; Xu, Yuesheng; Schmidtlein, C. R.; Lipson, Edward D.; Feiglin, David H.; Krol, Andrzej

    2015-03-01

    Wavelet transforms have been successfully applied in many fields of image processing. Yet, to our knowledge, they have never been directly incorporated to the objective function in Emission Computed Tomography (ECT) image reconstruction. Our aim has been to investigate if the ℓ1-norm of non-decimated discrete cosine transform (DCT) coefficients of the estimated radiotracer distribution could be effectively used as the regularization term for the penalized-likelihood (PL) reconstruction, where a regularizer is used to enforce the image smoothness in the reconstruction. In this study, the ℓ1-norm of 2D DCT wavelet decomposition was used as a regularization term. The Preconditioned Alternating Projection Algorithm (PAPA), which we proposed in earlier work to solve penalized likelihood (PL) reconstruction with non-differentiable regularizers, was used to solve this optimization problem. The DCT wavelet decompositions were performed on the transaxial reconstructed images. We reconstructed Monte Carlo simulated SPECT data obtained for a numerical phantom with Gaussian blobs as hot lesions and with a warm random lumpy background. Reconstructed images using the proposed method exhibited better noise suppression and improved lesion conspicuity, compared with images reconstructed using expectation maximization (EM) algorithm with Gaussian post filter (GPF). Also, the mean square error (MSE) was smaller, compared with EM-GPF. A critical and challenging aspect of this method was selection of optimal parameters. In summary, our numerical experiments demonstrated that the ℓ1-norm of discrete cosine transform (DCT) wavelet frame transform DCT regularizer shows promise for SPECT image reconstruction using PAPA method.

  8. SPECT in Alzheimer`s disease and the dementias

    SciTech Connect

    Bonte, F.J.

    1991-12-31

    Among 90 patients with a clinical diagnosis of Alzheimer`s disease (AD), two subgroups were identified for special study, including 42 patients who had a history of dementia in one or more first-degree relatives, and 14 who had a diagnosis of early AD. Of the 42 patients with a family history of dementia, 34 out of the 35 patients whose final clinical diagnosis was possible or probable AD had positive SPECT rCBF studies. Studies in the 14 patients thought to have very early AD were positive in 11 cases. This finding suggests that altered cortical physiology, and hence, rCBF, occurs quite early in the course of AD, perhaps before the onset of symptoms. It is possible that Xenon 133 rCBF studies might be used to detect the presence of subclinical AD in a population of individuals at risk to this disorder. Despite the drawbacks of a radionuclide with poor photon energy, Xenon 133, with its low cost and round-the-clock availability, deserves further study. Although the physical characteristics of Xenon 127 might make it preferable as a SPECT tracer, it is still not regularly available, and some instrument systems are not designed to handle its higher photon energies.

  9. Optimizing multi-pinhole SPECT geometries using an analytical model

    NASA Astrophysics Data System (ADS)

    Rentmeester, M. C. M.; van der Have, F.; Beekman, F. J.

    2007-05-01

    State-of-the-art multi-pinhole SPECT devices allow for sub-mm resolution imaging of radio-molecule distributions in small laboratory animals. The optimization of multi-pinhole and detector geometries using simulations based on ray-tracing or Monte Carlo algorithms is time-consuming, particularly because many system parameters need to be varied. As an efficient alternative we develop a continuous analytical model of a pinhole SPECT system with a stationary detector set-up, which we apply to focused imaging of a mouse. The model assumes that the multi-pinhole collimator and the detector both have the shape of a spherical layer, and uses analytical expressions for effective pinhole diameters, sensitivity and spatial resolution. For fixed fields-of-view, a pinhole-diameter adapting feedback loop allows for the comparison of the system resolution of different systems at equal system sensitivity, and vice versa. The model predicts that (i) for optimal resolution or sensitivity the collimator layer with pinholes should be placed as closely as possible around the animal given a fixed detector layer, (ii) with high-resolution detectors a resolution improvement up to 31% can be achieved compared to optimized systems, (iii) high-resolution detectors can be placed close to the collimator without significant resolution losses, (iv) interestingly, systems with a physical pinhole diameter of 0 mm can have an excellent resolution when high-resolution detectors are used.

  10. Myocardial Perfusion SPECT Imaging in Patients after Percutaneous Coronary Intervention.

    PubMed

    Georgoulias, Panagiotis; Valotassiou, Varvara; Tsougos, Ioannis; Demakopoulos, Nikolaos

    2010-05-01

    Coronary artery disease (CAD) is the most prevalent form of cardiovascular disease affecting about 13 million Americans, while more than one million percutaneous transluminal intervention (PCI) procedures are performed annually in the USA. The relative high occurrence of restenosis, despite stent implementation, seems to be the primary limitation of PCI. Over the last decades, single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), has proven an invaluable tool for the diagnosis of CAD and patients' risk stratification, providing useful information regarding the decision about revascularization and is well suited to assess patients after intervention. Information gained from post-intervention MPI is crucial to differentiate patients with angina from those with exo-cardiac chest pain syndromes, to assess peri-intervention myocardial damage, to predict-detect restenosis after PCI, to detect CAD progression in non-revascularized vessels, to evaluate the effects of intervention if required for occupational reasons and to evaluate patients' long-term prognosis. On the other hand, chest pain and exercise electrocardiography are largely unhelpful in identifying patients at risk after PCI.Although there are enough published data demonstrating the value of myocardial perfusion SPECT imaging in patients after PCI, there is still debate on whether or not these tests should be performed routinely.

  11. Intrinsic Feature Pose Measurement for Awake Animal SPECT Imaging

    SciTech Connect

    Goddard Jr, James Samuel; Baba, Justin S; Lee, Seung Joon; Weisenberger, A G; Stolin, A; McKisson, J; Smith, M F

    2009-01-01

    New developments have been made in optical motion tracking for awake animal imaging that measures 3D position and orientation (pose) for a single photon emission computed tomography (SPECT) imaging system. Ongoing SPECT imaging research has been directed towards head motion measurement for brain studies in awake, unrestrained mice. In contrast to previous results using external markers, this work extracts and tracks intrinsic features from multiple camera images and computes relative pose from the tracked features over time. Motion tracking thus far has been limited to measuring extrinsic features such as retro-reflective markers applied to the mouse s head. While this approach has been proven to be accurate, the additional animal handling required to attach the markers is undesirable. A significant improvement in the procedure is achieved by measuring the pose of the head without extrinsic markers using only the external surface appearance. This approach is currently being developed with initial results presented here. The intrinsic features measurement extracts discrete, sparse natural features from 2D images such as eyes, nose, mouth and other visible structures. Stereo correspondence between features for a camera pair is determined for calculation of 3D positions. These features are also tracked over time to provide continuity for surface model fitting. Experimental results from live images are presented.

  12. V/P SPECT as a diagnostic tool for pregnant women with suspected pulmonary embolism.

    PubMed

    Bajc, Marika; Olsson, Berit; Gottsäter, Anders; Hindorf, Cecilia; Jögi, Jonas

    2015-07-01

    The purpose of the study was to assess the prevalence of pulmonary embolism (PE) and other lung diseases among pregnant women with suspected PE and to calculate the radiation exposure to patient and fetus in this population. As a secondary aim, we evaluated the negative predictive value of a normal ventilation/perfusion single photon emission computed tomography (V/P SPECT) examination in pregnancy. We studied all 127 pregnant women who had suspected PE and had undergone V/P SPECT at our institution in the course of a 5-year period. Radiation exposure to patient and fetus and the negative predictive value of a normal V/P SPECT examination were also measured. V/P SPECT identified PE in 11 women (9%). Moreover, in 15 women (12%) the examination revealed pneumonia (in 2 cases in addition to PE) and in 1 woman signs of airway obstruction were revealed. Among the 116/127 women (91%) where PE was ruled out by V/P SPECT, none was diagnosed subsequently with PE or deep venous thrombosis (DVT) during the same pregnancy or puerperal period. For P SPECT, the calculated fetal absorbed dose was < 0.6 mGy,and the calculated breast absorbed dose 0.6 mGy. For V SPECT, the calculated fetal absorbed dose was < 0.014 mGy and the breast absorbed dose 0.25 mGy. The prevalence of PE was low (9%) among pregnant women with suspected disease. Pneumonia was diagnosed in 12% of patients. The negative predictive value of V/P SPECT was high, and the radiation exposure from V/P SPECT was low both for fetus and patient.

  13. The AAPM/RSNA physics tutorial for residents. Physics of SPECT.

    PubMed

    Tsui, B M

    1996-01-01

    Single-photon emission computed tomography (SPECT) provides three-dimensional (3D) image information about the distribution of a radiopharmaceutical injected into the patient for diagnostic purposes. By combining conventional scintigraphic and computed tomographic methods, SPECT images present 3D functional information about the patient in more detail and higher contrast than found in planar scintigrams. A typical SPECT system consists of one or more scintillation cameras that acquire multiple two-dimensional planar projection images around the patient. The projection data are reconstructed into 3D images. The collimator of the scintillation camera has substantial effects on the spatial resolution and detection efficiency of the SPECT system. Physical factors such as photon attenuation and scatter affect the quantitative accuracy and quality of SPECT images, and various methods have been developed to compensate for these image-degrading effects. In myocardial SPECT, an important application of SPECT, recent use of attenuation compensation methods has provided images with reduced artifacts and distortions caused by the non-uniform attenuation in the chest region and by the diaphragmatic and breast attenuation. Attenuation-compensated myocardial SPECT images have the potential to improve clinical diagnosis by reducing the false-positive and false-negative detection of myocardial defects. In the future, further improvement in SPECT images will be realized from the continuous development of new radio-pharmaceuticals for new clinical applications, instrumentation with high spatial resolution and detection efficiency, and image reconstruction algorithms and compensation methods that reduce the image-degrading effects of the collimator-detector, attenuation, and scatter.

  14. Clinical Utility of Tc-99m MIBI SPECT/CT for Preoperative Localization of Parathyroid Lesions.

    PubMed

    Ozkan, Zeynep Gozde; Unal, Seher Nilgun; Kuyumcu, Serkan; Sanli, Yasemin; Gecer, Mehmet Fatih; Ozcinar, Beyza; Giles, Yasemin Senyurek; Erbil, Yesim

    2017-08-01

    We aimed to demonstrate the role of SPECT/CT in preoperative localization of parathyroid lesions in patients with hyperparathyroidism who had technetium-99m (Tc-99m) methoxyisobutylisonitrile (MIBI) dual-phase parathyroid scintigraphy. We evaluated retrospectively the scintigraphic data of 103 patients who had parathyroidectomy after Tc-99m MIBI dual-phase parathyroid scintigraphy with SPECT/CT. The planar and SPECT/CT images were evaluated separately to determine their efficacy in localizing parathyroid lesions. These results were then compared with surgical data. There were 84 female and 19 male patients whose mean age was 54 ± 12 years. A total of 115 parathyroid lesions in 103 patients were resected during operations. In 87 patients, with both planar and SPECT/CT images, a total of 100 lesions could be detected correctly. In 11 patients, only SPECT/CT images could show 13 subcentimetric lesions. In three patients, three lesions were evaluated as parathyroid lesions both with planar and SPECT/CT images, but according to histopathologic evaluation, they came out to be nonparathyroidal lesions. In two patients, two parathyroid lesions could not be detected preoperatively neither with planar nor with SPECT/CT images. The lesion-based sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87 %, 99 %, 97.1 %, 95.3 %, and 95.8 % for planar images and 98.3 %, 99 %, 97.4 %, 99.4 %, and 98.8 % for SPECT/CT images, respectively. Tc-99m MIBI parathyroid scintigraphy should be a diagnostic modality of choice in preoperative evaluation of patients with hyperparathyroidism. SPECT/CT has an incremental value both in demonstrating subcentimetric lesions and in accurately localizing lesions anatomically.

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

    SciTech Connect

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

    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-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

  16. Ventilation/Perfusion SPECT for diagnostics of pulmonary embolism in clinical practice.

    PubMed

    Bajc, M; Olsson, B; Palmer, J; Jonson, B

    2008-10-01

    The aim of this retrospective study is to illustrate clinical utility and impact of pulmonary embolism (PE) diagnostics of up to date Ventilation/Perfusion SPECT (V/P (SPECT)) applying holistic interpretation criteria. During a 2-year period 2328 consecutive patients referred to V/P(SPECT) for clinically suspected PE were examined. Final diagnosis was established by physicians clinically responsible for patient care. To establish the performance of V/P(SPECT) negative for PE, patients were followed up by medical records for 6 months. Ventilation/Perfusion SPECT was feasible in 99% of the patients. Data for follow-up were available in 1785 patients (77%). PE was reported in 607 patients (34%). Normal pattern was described in 420 patients (25%). Pathology other than PE such as a pneumonia, left heart failure, obstructive lung disease, tumour was described in 724 patients (41%). Report was nondiagnostic in 19 patients (1%). Six cases were classified as falsely negative because PE was diagnosed at follow-up and was fatal in one case. Six cases were classified as falsely positive because the clinician decided not to treat. In 608 patients with final PE diagnosis, 601 patients had positive V/P(SPECT) (99%). In 1177 patients without final PE diagnosis 1153 patients had negative V/P(SPECT) (98%). Holistic interpretation of V/P(SPECT,) yields high negative and positive predictive values and only 1% of nondiagnostic findings and was feasible in 99% of patients. It is a responsibility and a challenge of nuclear medicine to provide optimal care of patients with suspected PE by making V/P(SPECT) available.

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

    SciTech Connect

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

    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-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

  18. Detection of neoplastic meningitis in a patient with gastric cancer by thallium-201 SPECT.

    PubMed

    Tonomura, Yasuyo; Kataoka, Hiroshi; Terashima, Mari; Shinkai, Takayuki; Ueno, Satoshi

    2009-01-01

    We describe the usefulness of thallium-201 SPECT in a patient with neoplastic meningitis (NM) from gastric carcinoma. Thallium-201 SPECT is of value for the diagnosis of cancer; retention of thallium-201 on delayed images strongly suggests malignancy. NM is a lethal, major neurologic complication of cancer. The standard for the diagnosis of NM is cytologic confirmation of malignant cells in CSF, but cytologic results are often negative (estimated false negative rate, 50%), even when NM is strongly suspected clinically. In patients with equivocal findings, our findings suggest that thallium-201 SPECT is one helpful tool for the detection of NM, particularly when associated with signet-ring cell carcinoma.

  19. Noninvasive Nuclear SPECT Myocardial Blood Flow Quantitation to Guide Management for Coronary Artery Disease.

    PubMed

    Chen, Lung-Ching; Jong, Bor-Hsin; Lin, Sheng-Che; Ku, Chi-Tai; Chen, Ing-Jou; Chen, Yen-Kung; Hsu, Bailing

    2017-09-01

    Recently, myocardial blood flow quantitation with dynamic SPECT has been validated to enhance the detection of multivessel coronary artery disease (CAD) and conclude equivocal SPECT myocardial perfusion study. This advance opened an important clinical application to utilize the tool in guiding CAD management for area where myocardial perfusion tracers for PET are unavailable or unaffordable. We present a clinical patient with ongoing recursive angina who underwent multiple nuclear stress tests for a sequence of CAD evaluation in 26 months and demonstrated that SPECT myocardial blood flow quantitation properly guided CAD management to warrant patient outcome.

  20. Sequential sup 123 I-IMP-SPECT in acute infantile hemiplegia

    SciTech Connect

    Shirasaka, Y.; Ito, M.; Okuno, T.; Fujii, T.; Mikawa, H. )

    1989-09-01

    Sequential {sup 123}I-N-isopropyl-p-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) was performed in 2 patients with acute infantile hemiplegia. In both patients, low uptake of IMP was detected in the targeted abnormal hemisphere. The {sup 123}I-IMP-SPECT findings indicative of a pathologic condition persisted even when the clinical findings and electroencephalographic abnormalities improved. Because of its sensitivity, noninvasiveness, and accurate reflection of the cerebral blood flow distribution, {sup 123}I-IMP-SPECT is useful in the examination of acute infantile hemiplegia and in the evaluation of prognosis.

  1. SPECT imaging in evaluating extent of malignant external otitis: case report

    SciTech Connect

    English, R.J.; Tu'Meh, S.S.; Piwnica-Worms, D.; Holman, B.L.

    1987-03-01

    Otitis externa, a benign inflammatory process of the external auditory canal, is general responsive to local therapy. Some patients however, develop a less controllable disease leading to chondritis and osteomyelitis of the base of the skull. The direct invasive characteristic of the disease has led to the descriptive term malignant external otitis (MEO), more appropriately called necrotizing or invasive external otitis. Malignant external otitis is caused by an aggressive pseudomonas or proteus infection that almost exclusively occurs in elderly diabetic patients. The primary imaging modalities previously used in the diagnosis and evaluation of MEO were standard planar scintigraphic techniques with technetium-99M (/sup 99m/Tc) bone agents and gallium-67 (/sup 67/Ga), and pluridirectional tomography. The advent of high resolution computed tomography (CT) effectively allowed demonstration of the soft tissue extension and bone destruction associated with MEO, but still suffered from the low sensitivity constraints of all radiographic techniques in determining early inflammatory bone involvement. Recent work suggests that scintigraphic detection of MEO with /sup 99m/Tc-MDP and /sup 67/Ga, combined with the cross-sectional resolution of single photon emission computed tomography (SPECT) may be of value in planning treatment of this inflammatory condition.

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

    SciTech Connect

    Jackson, Price A.; Kron, Tomas; Beauregard, Jean-Mathieu; Hofman, Michael S.; Hogg, Annette; Hicks, Rodney J.

    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 based 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.

  3. Low-dose computed tomography scans with automatic exposure control for patients of different ages undergoing cardiac PET/CT and SPECT/CT.

    PubMed

    Yang, Ching-Ching; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin; Liu, Shu-Hsin

    2017-06-01

    This study aimed to evaluate the efficacy of automatic exposure control (AEC) in order to optimize low-dose computed tomography (CT) protocols for patients of different ages undergoing cardiac PET/CT and single-photon emission computed tomography/computed tomography (SPECT/CT). One PET/CT and one SPECT/CT were used to acquire CT images for four anthropomorphic phantoms representative of 1-year-old, 5-year-old and 10-year-old children and an adult. For the hybrid systems investigated in this study, the radiation dose and image quality of cardiac CT scans performed with AEC activated depend mainly on the selection of a predefined image quality index. Multiple linear regression methods were used to analyse image data from anthropomorphic phantom studies to investigate the effects of body size and predefined image quality index on CT radiation dose in cardiac PET/CT and SPECT/CT scans. The regression relationships have a coefficient of determination larger than 0.9, indicating a good fit to the data. According to the regression models, low-dose protocols using the AEC technique were optimized for patients of different ages. In comparison with the standard protocol with AEC activated for adult cardiac examinations used in our clinical routine practice, the optimized paediatric protocols in PET/CT allow 32.2, 63.7 and 79.2% CT dose reductions for anthropomorphic phantoms simulating 10-year-old, 5-year-old and 1-year-old children, respectively. The corresponding results for cardiac SPECT/CT are 8.4, 51.5 and 72.7%. AEC is a practical way to reduce CT radiation dose in cardiac PET/CT and SPECT/CT, but the AEC settings should be determined properly for optimal effect. Our results show that AEC does not eliminate the need for paediatric protocols and CT examinations using the AEC technique should be optimized for paediatric patients to reduce the radiation dose as low as reasonably achievable.

  4. Financial and clinical implications of low-energy CT combined with 99m Technetium-sestamibi SPECT for primary hyperparathyroidism.

    PubMed

    Pata, Giacomo; Casella, Claudio; Magri, Gian Carlo; Lucchini, Silvia; Panarotto, Maria Beatrice; Crea, Nicola; Giubbini, Raffaele; Salerni, Bruno

    2011-09-01

    (99m)Technetium-sestamibi hybrid SPECT/CT has been favored over conventional SPECT in preoperative evaluation of primary hyperparathyroidism (PHPT) patients. However, the financial implications of CT-image acquisition have never before been published. This prompted us to perform a cost analysis of the aforementioned nuclear procedures. A total of 55 PHPT patients operated on between 2004 and 2009 were studied. Overall, 27 patients underwent SPECT and 28 SPECT/CT. Localization results, as well as diagnostic and clinical cost variations between SPECT and SPECT/CT patients, were compared. SPECT/CT revealed higher sensitivity than SPECT (96.7 vs 79.3%; P = .011), as well as higher specificity (96.4 vs 82.4%; P = .037) and positive predictive value (PPV) (96.7 vs 83%; P = .038) for correctly identifying the neck-side affected by PHPT. Likewise, SPECT/CT disclosed higher sensitivity (86.7 vs 61.1%; P < .0001), specificity (97.4 vs 90%; P = .022), and PPV (86.7 vs 65.7%; P = .0001) for correct neck-quadrant identification. The mean operative time decreased from 62 min following SPECT to 36 min following SPECT/CT (P < .0001), yielding a mean surgical expense saving of 109.9 /patient (updated at 2009/2010 billing database). SPECT/CT actually ensures a mean expenditure reduction of 98.7 /patient (95% CI: 47.96 -149.42 ), diagnostic costs variation amounting to 11.2 /procedure. SPECT/CT ensures better focus for the surgical exploration, shortens surgical times, and eventually cuts costs when used for localization of parathyroid adenomas.

  5. Implementation of technetium-99m MIBI SPECT imaging guidelines: optimizing the two day stress-rest protocol.

    PubMed

    Lavalaye, J M; Schroeder-Tanka, J M; Tiel-van Buul, M M; van der Wall, E E; Lie, K I; van Royen, E A

    1997-08-01

    In a previous study in 460 patients, we found that in patients with suspected or known coronary artery disease undergoing stress-rest technetium-99m sestamibi (MIBI) SPECT myocardial perfusion imaging, rest SPECT imaging could be withhold in approximately 20% of patients because of a completely normal stress study. The present study was set up to evaluate the consequences of the implementation of this finding in a subsequent population of patients, and to set standards for the variety of protocols now used for MIBI SPECT imaging. Within a period of 4 months, 235 consecutive patients referred for MIBI SPECT scintigraphy were studied. All patients had stable cardiac chest pain and underwent symptom-limited exercise MIBI SPECT perfusion imaging. The stress SPECT images were reconstructed and evaluated immediately after acquisition of the images. In case of a clearly normal stress SPECT study, rest imaging was cancelled. Twenty-six of 235 patients (11%) had a completely normal stress MIBI SPECT study and the rest SPECT imaging procedure could be subsequently cancelled. In 20 patients (9%) the stress SPECT was inconclusive, and in 189 (80%) of patients stress imaging was clearly abnormal. In the first month of the study, the nuclear medicine physicians and cardiologists would interprete only 6% of the stress images as normal, while this number increased to 13% after 9 weeks, with a mean of 11% for the whole investigation period of 4 months. In patients undergoing stress MIBI SPECT imaging, it was found justified to cancel rest MIBI SPECT imaging in at least 11% of patients because of a completely normal stress SPECT. As 9% of the images were inconclusive, the number of normal stress images could theoretically increase to 20% if reliable measures are taken to improve reading accuracy. This number is in close agreement with the number of normal stress studies previously reported by our institution and would lead to a considerable reduction of radiation dose, costs, and

  6. A parallel-cone collimator for high-energy SPECT.

    PubMed

    Beijst, Casper; Elschot, Mattijs; Viergever, Max A; de Jong, Hugo W A M

    2015-03-01

    In SPECT using high-energy photon-emitting isotopes, such as (131)I, parallel-hole collimators with thick septa are required to limit septal penetration, at the cost of sensitivity and resolution. This study investigated a parallel-hole collimator with cone-shaped holes, which was designed to limit collimator penetration while preserving resolution and sensitivity. The objective was to demonstrate that a single-slice prototype of the parallel-cone (PC) collimator was capable of improving the image quality of high-energy SPECT. The image quality of the PC collimator was quantitatively compared with that of clinically used low-energy high-resolution (LEHR; for (99m)Tc) and high-energy general-purpose (HEGP; for (131)I and (18)F) parallel-hole collimators. First, Monte Carlo simulations of single and double point sources were performed to assess sensitivity and resolution by comparing point-spread functions (PSFs). Second, a prototype PC collimator was used in an experimental phantom study to assess and compare contrast recovery coefficients and image noise. Monte Carlo simulations showed reduced broadening of the PSF due to collimator penetration for the PC collimator as compared with the HEGP collimator (e.g., 0.9 vs. 1.4 cm in full width at half maximum for (131)I). Simulated double point sources placed 2 cm apart were separately detectable for the PC collimator, whereas this was not the case for (131)I and (18)F at distances from the collimator face of 10 cm or more for the HEGP collimator. The sensitivity, measured over the simulated profiles as the total amount of counts per decay, was found to be higher for the LEHR and HEGP collimators than for the PC collimator (e.g., 3.1 × 10(-5) vs. 2.9 × 10(-5) counts per decay for (131)I). However, at equal noise level, phantom measurements showed that contrast recovery coefficients were similar for the PC and LEHR collimators for (99m)Tc but that the PC collimator significantly improved the contrast recovery

  7. A high-sensitivity small animal SPECT system

    NASA Astrophysics Data System (ADS)

    Mitchell, Gregory S.; Cherry, Simon R.

    2009-03-01

    Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma rays, often less than 0.1%. A system for small animal SPECT imaging which uses no collimators could potentially achieve very high sensitivity—several tens of percent—with reasonably sized detectors. This would allow two significant improvements in preclinical studies: images could be obtained more rapidly, allowing higher throughput for screening applications, or for dynamic processes to be observed with very good time resolution; and images could be obtained with less radioactive tracer, making possible the in vivo imaging of low-capacity receptor systems, aiding research into new tracer compounds, and reducing the cost and easing the regulatory burden of an experiment. Of course, a system with no collimator will not be able to approach the submillimeter spatial resolutions produced by the most advanced pinhole and collimated systems, but a high-sensitivity system with resolution of order 1 cm could nonetheless find significant and new use in the many molecular imaging applications which do not require good spatial resolution—for example, screening applications for drug development or new imaging agents. Rather than as an alternative to high-resolution SPECT systems, the high-sensitivity system is proposed as a radiotracer alternative to optical imaging for small animals. We have developed a prototype system for mouse imaging applications. The scanner consists of two large, thin, closely spaced scintillation detectors. Simulation studies indicate that a FWHM spatial resolution of 7 mm is possible. In an in vivo mouse imaging study using the 99mTc labeled tracer MAG-3, the sensitivity of the

  8. 99mTc-HMPAO perfusion SPECT/CT in the diagnosis of brain death.

    PubMed

    Derlin, Thorsten; Weiberg, Desiree

    2016-01-01

    This report describes a case of brain death (BD) evaluated by 99mTc-hexamethylpropylene amine oxime (HMPAO) single photon emission tomography/computed tomography (SPECT/CT). A 16-year-old boy with a history of rapid unexpected brain herniation due to pilocytic astrocytoma underwent 99mTc-HMPAO SPECT/CT for evaluation of brain death in the context of organ donation. Flow images demonstrated lack of blood flow to the brain, and delayed images showed absence of demonstrable radionuclide activity within the brain. SPECT/CT confirmed absence of tracer accumulation, and was deemed helpful for evaluation of the brain stem. 99mTc-HMPAO SPECT/CT is a valuable tool enabling imaging-based confirmation of BD.

  9. SPECT assay of radiolabeled monoclonal antibodies. Comprehensive progress report, September 1989--February 1992

    SciTech Connect

    Jaszczak, R.J.

    1992-02-01

    The long-term goal of this research project is to develop methods to improve the utility of single photon emission computed tomography (SPECI) to quantify the biodistribution of monoclonal antibodies (MoAbs) labeled with clinically relevant radionuclides ({sup 123}I, {sup 131}I, and {sup 111}In) and with another radionuclide,{sup 211}At, recently used in therapy. We describe here our progress in developing quantitative SPECT methodology for {sup 111}In and {sup 123}I. We have focused our recent research thrusts on the following aspects of SPECT: (1) The development of improved SPECT hardware, such as improved acquisition geometries. (2) The development of better reconstruction methods that provide accurate compensation for the physical factors that affect SPECT quantification. (3) The application of carefully designed simulations and experiments to validate our hardware and software approaches.

  10. Clinical application of SPECT in adrenal imaging with iodine-131 6 beta-iodomethyl-19-norcholesterol

    SciTech Connect

    Ishimura, J.; Kawanaka, M.; Fukuchi, M.

    1989-04-01

    Forty-one patients with or without adrenocortical disorders were studied to evaluate the clinical usefulness of SPECT in adrenal imaging with I-131 Adosterol. In the SPECT images from this study, all glands with either normally functioning or hyperfunctioning adrenal cortices could be detected, while those glands with hypofunctioning adrenal cortices could not be detected. Particularly in transaxial and sagittal slices, the adrenal gland was identified posteriorly and was clearly distinguished from the gallbladder. In preliminary results using SPECT by a standard method, uptake in 68 detectable glands ranged from 1.7% to 4.9% in four glands with Cushing's syndrome, from 1.1% to 1.3% in seven glands with primary aldosteronism, and were distributed below 1.0% in the remaining glands with normally functioning adrenal cortices. These data show that it is possible to evaluate the adrenocortical functioning status simply by analyzing the SPECT images of the adrenal.

  11. 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

  12. Pre-reconstruction restoration of SPECT projection images by a neural network

    SciTech Connect

    Gopal, S.S.; Hebert, T.J. . Dept. of Electrical Engineering)

    1994-08-01

    In single photon emission computed tomography (SPECT) the projection images obtained at view angles surrounding the patient are degraded due to the geometric response of the imaging system (a spatially-variant blur), Compton scatter, Poisson noise, and other factors. Various methods have been proposed for compensating for the spatially varying geometric response of the camera. In this study the authors examine restoration of SPECT projection images using an artificial neural network. A three layer feed-forward neural network is trained to compute the spatially-variant standard deviations of a symmetric Gaussian blur. A Hopfield network is then used to restore the projection images in which the restoration problem is formulated as a minimization of an error function of the network. Results from applying this restoration procedure on SPECT projection images are presented and the resulting SPECT reconstruction are analyzed.

  13. A SPECT study in internal carotid artery occlusion: Discrepancies between flow image and neurologic deficits

    SciTech Connect

    Moriwaki, H.; Hougaku, H.; Matsuda, I.; Kusunoki, M.; Shirai, J. )

    1989-08-01

    A SPECT (single photon emission computed tomography) study in internal carotid artery (ICA) occlusion was performed in 6 patients. The validity of iodoamphetamine (IMP) SPECT study in the evaluation of cerebral blood flow (CBF) or neurologic function is still controversial. In this study, the authors showed several cases in whom SPECT images of brain were not compatible with their neurologic deficits. In 2 typical cases, a large low-density area was observed in the non-dominant hemisphere in computed tomography (CT) scan, but no apparent motor-sensory deficits in left limbs were present. In these patients, SPECT study also revealed flow reduction in the affected side of the brain. So there was a possibility that an IMP brain image could not always reflect CBF, which maintains neurologic function of the brain.

  14. U-SPECT-BioFluo: an integrated radionuclide, bioluminescence, and fluorescence imaging platform

    PubMed Central

    2014-01-01

    Background In vivo bioluminescence, fluorescence, and single-photon emission computed tomography (SPECT) imaging provide complementary information about biological processes. However, to date these signatures are evaluated separately on individual preclinical systems. In this paper, we introduce a fully integrated bioluminescence-fluorescence-SPECT platform. Next to an optimization in logistics and image fusion, this integration can help improve understanding of the optical imaging (OI) results. Methods An OI module was developed for a preclinical SPECT system (U-SPECT, MILabs, Utrecht, the Netherlands). The applicability of the module for bioluminescence and fluorescence imaging was evaluated in both a phantom and in an in vivo setting using mice implanted with a 4 T1-luc + tumor. A combination of a fluorescent dye and radioactive moiety was used to directly relate the optical images of the module to the SPECT findings. Bioluminescence imaging (BLI) was compared to the localization of the fluorescence signal in the tumors. Results Both the phantom and in vivo mouse studies showed that superficial fluorescence signals could be imaged accurately. The SPECT and bioluminescence images could be used to place the fluorescence findings in perspective, e.g. by showing tracer accumulation in non-target organs such as the liver and kidneys (SPECT) and giving a semi-quantitative read-out for tumor spread (bioluminescence). Conclusions We developed a fully integrated multimodal platform that provides complementary registered imaging of bioluminescent, fluorescent, and SPECT signatures in a single scanning session with a single dose of anesthesia. In our view, integration of these modalities helps to improve data interpretation of optical findings in relation to radionuclide images. PMID:25386389

  15. Hotspot quantification of myocardial focal tracer uptake from molecular targeted SPECT/CT images: experimental validation

    NASA Astrophysics Data System (ADS)

    Liu, Yi-Hwa; Sahul, Zakir; Weyman, Christopher A.; Ryder, William J.; Dione, Donald P.; Dobrucki, Lawrence W.; Mekkaoui, Choukri; Brennan, Matthew P.; Hu, Xiaoyue; Hawley, Christi; Sinusas, Albert J.

    2008-03-01

    We have developed a new single photon emission computerized tomography (SPECT) hotspot quantification method incorporating extra cardiac activity correction and hotspot normal limit estimation. The method was validated for estimation accuracy of myocardial tracer focal uptake in a chronic canine model of myocardial infarction (MI). Dogs (n = 4) at 2 weeks post MI were injected with Tl-201 and a Tc-99m-labeled hotspot tracer targeted at matrix metalloproteinases (MMPs). An external point source filled with Tc-99m was used for a reference of absolute radioactivity. Dual-isotope (Tc-99m/Tl-201) SPECT images were acquired simultaneously followed by an X-ray CT acquisition. Dogs were sacrificed after imaging for myocardial gamma well counting. Images were reconstructed with CT-based attenuation correction (AC) and without AC (NAC) and were quantified using our quantification method. Normal limits for myocardial hotspot uptake were estimated based on 3 different schemes: maximum entropy, meansquared-error minimization (MSEM) and global minimization. Absolute myocardial hotspot uptake was quantified from SPECT images using the normal limits and compared with well-counted radioactivity on a segment-by-segment basis (n = 12 segments/dog). Radioactivity was expressed as % injected dose (%ID). There was an excellent correlation (r = 0.78-0.92) between the estimated activity (%ID) derived using the SPECT quantitative approach and well-counting, independent of AC. However, SPECT quantification without AC resulted in the significant underestimation of radioactivity. Quantification using SPECT with AC and the MSEM normal limit yielded the best results compared with well-counting. In conclusion, focal myocardial "hotspot" uptake of a targeted radiotracer can be accurately quantified in vivo using a method that incorporates SPECT imaging with AC, an external reference, background scatter compensation, and a suitable normal limit. This hybrid SPECT/CT approach allows for the serial

  16. Radiation risk and protection of patients in clinical SPECT/CT.

    PubMed

    Brix, Gunnar; Nekolla, Elke A; Borowski, Markus; Noßke, Dietmar

    2014-05-01

    Clinical studies have demonstrated that hybrid single photon emission computed tomography (SPECT)/CT for various diagnostic issues has an added value as compared to SPECT alone. However, the combined acquisition of functional and anatomical images can substantially increase radiation exposure to patients, in particular when using a hybrid system with diagnostic CT capabilities. It is, therefore, essential to carefully balance the diagnostic needs and radiation protection requirements. To this end, the evidence on health effects induced by ionizing radiation is outlined. In addition, the essential concepts for estimating radiation doses and lifetime attributable cancer risks associated with SPECT/CT examinations are presented taking into account both the new recommendations of the International Commission on Radiological Protection (ICRP) as well as the most recent radiation risk models. Representative values of effective dose and lifetime attributable risk are reported for ten frequently used SPECT radiopharmaceuticals and five fully diagnostic partial-body CT examinations. A diagnostic CT scan acquired as part of a combined SPECT/CT examination contributes considerably to, and for some applications even dominates, the total patient exposure. For the common SPECT and CT examinations considered in this study, the lifetime attributable risk of developing a radiation-related cancer is less than 0.27 %/0.37 % for men/women older than 16 years, respectively, and decreases markedly with increasing age at exposure. Since there is no clinical indication for a SPECT/CT examination unless an emission scan has been indicated, the issue on justification comes down to the question of whether it is necessary to additionally acquire a low-dose CT for attenuation correction and anatomical localization of tracer uptake or even a fully diagnostic CT. In any case, SPECT/CT studies have to be optimized, e.g. by adapting dose reduction measures from state-of-the-art CT practice, and

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

    SciTech Connect

    Taki, J.; Nakajima, K.; Bunko, H.; Ohguchi, M.; Tonami, N.; Hisada, K. )

    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.

  18. U-SPECT-BioFluo: an integrated radionuclide, bioluminescence, and fluorescence imaging platform.

    PubMed

    van Oosterom, Matthias N; Kreuger, Rob; Buckle, Tessa; Mahn, Wendy A; Bunschoten, Anton; Josephson, Lee; van Leeuwen, Fijs Wb; Beekman, Freek J

    2014-01-01

    In vivo bioluminescence, fluorescence, and single-photon emission computed tomography (SPECT) imaging provide complementary information about biological processes. However, to date these signatures are evaluated separately on individual preclinical systems. In this paper, we introduce a fully integrated bioluminescence-fluorescence-SPECT platform. Next to an optimization in logistics and image fusion, this integration can help improve understanding of the optical imaging (OI) results. An OI module was developed for a preclinical SPECT system (U-SPECT, MILabs, Utrecht, the Netherlands). The applicability of the module for bioluminescence and fluorescence imaging was evaluated in both a phantom and in an in vivo setting using mice implanted with a 4 T1-luc + tumor. A combination of a fluorescent dye and radioactive moiety was used to directly relate the optical images of the module to the SPECT findings. Bioluminescence imaging (BLI) was compared to the localization of the fluorescence signal in the tumors. Both the phantom and in vivo mouse studies showed that superficial fluorescence signals could be imaged accurately. The SPECT and bioluminescence images could be used to place the fluorescence findings in perspective, e.g. by showing tracer accumulation in non-target organs such as the liver and kidneys (SPECT) and giving a semi-quantitative read-out for tumor spread (bioluminescence). We developed a fully integrated multimodal platform that provides complementary registered imaging of bioluminescent, fluorescent, and SPECT signatures in a single scanning session with a single dose of anesthesia. In our view, integration of these modalities helps to improve data interpretation of optical findings in relation to radionuclide images.

  19. Modeling of the Sensitivity of Fan-Beam Collimation in Spect Imaging

    DTIC Science & Technology

    2007-11-02

    dB by the manufacturer and by projection measurements of a uniform flood source. 2 THEORY 2.1 Ideal collimation Consider a schematic representation of...MODELING OF THE SENSITIVITY OF FAN-BEAM COLLIMATION IN SPECT IMAGING Michel Koolex, Yves D’Asselerx, Stefaan Vandenberghex, Rik Van de Wallex, Koen...Nuclear Medicine Division, University Hospital of Ghent, De Pintelaan 185 B-9000 Ghent, Belgium Abstract An essential feature of SPECT imaging is

  20. 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.

  1. Radiolabeled Sugars Used for PET and SPECT Imaging.

    PubMed

    Barrios-Lopez, Brianda; Bergstrom, Kim

    2016-01-01

    There are new efforts to develop "sugar" probes for molecular imaging focusing on human clinical studies. Radiolabeled carbohydrates are used as substrate probes for studying specific processes in tissues and organisms. The best application case is 2-Deoxy-2-[18F]fluoro-D-glucose (18F-FDG), which is incorporated by cancer cells. The introduction of ltF-FDG has advanced enormously human Positron Emission Tomography (PET). This review focuses on the importance of 18FFDG and other sugars as imaging probes in PET and Single Photon Emission Computed Tomography (SPECT) imaging. In conclusion, new radiolabeled molecules that can be used as radiopharmaceuticals also would possibly help in the treatment of cancer cells in human patients. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  2. A Modified Post Processing Correction Matrix For SPECT

    NASA Astrophysics Data System (ADS)

    Macey, D. J.; DeNardo, G. L.; DeNardo, S. J.; Seibert, J. A.

    1986-01-01

    A post reconstruction method of attenuation compensation for Single Photon Emission Computed Tomography (SPECT) has been investigated that offers a new approach to the problem of quantitation. A modified correction matrix is generated for attenuation compensation in which the Linear Attenuation Coefficient (LAC) for each pixel is assigned a value depending on the radial distance of the pixel from the true section boundary. Attenuation compensation of transverse section images of small and large volume sources of Tc-99m in phantoms using this modified matrix indicated that a known quantity of radionuclide could be determined to better than 10%. The scatter fraction was estimated as the difference in the corrected section images using a multiplicative matrix generated with a constant LAC for each pixel and the modified matrix proposed in this report.

  3. High resolution SPECT, small deep infarcts and diaschisis.

    PubMed Central

    Bowler, J V; Costa, D C; Jones, B E; Steiner, T J; Wade, J P

    1992-01-01

    Eighteen cases of lacunar infarction are presented. Six of these cases had a purely motor clinical deficit. All the cases were studied by serial high resolution SPECT (single photon emission computerized tomography) using 99Tcm HMPAO. The degree and extent of the changes in cerebral perfusion consistent with diaschisis were noted and these compared with the severity of the clinical deficit at presentation and over time. No significant correlation between diaschisis and the clinical state was found at any stage. The nature, aetiology and importance of diaschisis are discussed and it is suggested that caution should be exercised in attributing clinical features to diaschisis simply because it may be present. Images Figure 1. Figure 2. PMID:1556715

  4. Tomographic mesh generation for OSEM reconstruction of SPECT images

    NASA Astrophysics Data System (ADS)

    Lu, Yao; Yu, Bo; Vogelsang, Levon; Krol, Andrzej; Xu, Yuesheng; Hu, Xiaofei; Feiglin, David

    2009-02-01

    To improve quality of OSEM SPECT reconstruction in the mesh domain, we implemented an adaptive mesh generation method that produces tomographic mesh consisting of triangular elements with size and density commensurate with geometric detail of the objects. Node density and element size change smoothly as a function of distance from the edges and edge curvature without creation of 'bad' elements. Tomographic performance of mesh-based OSEM reconstruction is controlled by the tomographic mesh structure, i.e. node density distribution, which in turn is ruled by the number of key points on the boundaries. A greedy algorithm is used to influence the distribution of nodes on the boundaries. The relationship between tomographic mesh properties and OSEM reconstruction quality has been investigated. We conclude that by selecting adequate number of key points, one can produce a tomographic mesh with lowest number of nodes that is sufficient to provide desired quality of reconstructed images, appropriate for the imaging system properties.

  5. Attenuation compensation in mesh-domain OSEM SPECT reconstruction

    NASA Astrophysics Data System (ADS)

    Vogelsang, Levon; Lu, Yao; Yu, Bo; Krol, Andrzej; Xu, Yuesheng; Hu, Xiaofei; Feiglin, David; Lipson, Edward

    2009-02-01

    A new method for attenuation compensation (AC) in mesh-domain SPECT OSEM reconstruction using strip-area approximation (SAAC) is introduced and compared to single-ray AC (SRAC). SAAC uses the polygonal area of the intersection of a mesh element (ME) and a tube-of-response (TOR) for defining an effective length of photon transit and an effective attenuation coefficient. This approach to AC is compared to SRAC, which defines the effective length of photon transit as the intersection of a single ray and a ME and the effective attenuation coefficient as the mean along the ray path. Comparative quantitative and qualitative analysis demonstrated that SAAC outperformed SRAC in terms of reconstruction image accuracy and quality.

  6. PET/SPECT imaging agents for neurodegenerative diseases

    PubMed Central

    Zhu, Lin; Ploessl, Karl; Kung, Hank F.

    2014-01-01

    Single photon emission computed tomography (SPECT) or positron emission computed tomography (PET) imaging agents for neurodegenerative disease have a significant impact on clinical diagnosis and patient care. The examples of Parkinson’s Disease (PD) and Alzheimer’s Disease (AD) imaging agents described in this paper provide a general view on how imaging agents, ie radioactive drugs, are selected, chemically prepared and applied in humans. Imaging the living human brain can provide unique information on the pathology and progression of neurodegenerative diseases, such as AD and PD. The imaging method will also facilitate preclinical and clinical trials of new drugs offering specific information related to drug binding sites in the brain. In the future, chemists will continue to play important roles in identifying specific targets, synthesizing target-specific probes for screening and ultimately testing them by in vitro and in vivo assays. PMID:24676152

  7. Noise-Weighted FBP Algorithm for Uniformly Attenuated SPECT Projections

    NASA Astrophysics Data System (ADS)

    Zeng, Gengsheng L.

    2016-06-01

    Noise-weighted FBP (filtered backprojection) algorithm and Bayesian FBP algorithm were developed recently for un-attenuated Radon transform, which have applications in x-ray CT (computed tomography). This paper extends the noise-weighted FBP algorithm to the case of uniformly attenuated Radon transform, and this extended FBP algorithm can be applied in uniformly attenuated SPECT (single photon emission computed tomography). Computer simulations and experimental data demonstrate that the proposed FBP algorithm has similar noise control capability as the iterative ML-EM (maximum likelihood expectation maximization) algorithm. In practice, the attenuator is rarely uniform. A stable FBP algorithm must be developed for non-uniform attenuators before the FBP algorithm can be applied in clinics when attenuation correction is required.

  8. The role of single-photon emission computed tomography and SPECT/computed tomography in oncologic imaging.

    PubMed

    Brandon, David; Alazraki, Adina; Halkar, Raghuveer K; Alazraki, Naomi P

    2011-02-01

    Single-photon emission computed tomography (SPECT) and hybrid SPECT/computed tomography (SPECT/CT) cameras have emerged as a dominant technology providing invaluable tools in the diagnosis, staging, therapy planning, and treatment monitoring of multiple cancers over the past decade. In the same way that positron emission tomography (PET) benefited from the addition of CT, functional SPECT and anatomic CT data obtained as a single study have shown improvements in diagnostic imaging sensitivity and specificity by improving lesion conspicuity, reducing false positives, and clarifying indeterminate lesions. Furthermore, the anatomic imaging better localizes the functional data, which can be critical in surgical and therapy planning. As more disease-specific imaging agents become available, the role of SPECT/CT in the new paradigms of molecular imaging for personalized medicine will expand. Established and emerging uses of SPECT/CT in a wide variety of oncologic diseases, as well as radiation exposure issues, are reviewed. Published by Elsevier Inc.

  9. SemiSPECT: A small-animal SPECT imager based on eight cadmium zinc tellurium detector arrays

    NASA Astrophysics Data System (ADS)

    Kim, Hyunki

    We have completed a new small-animal imaging system, called SemiSPECT, based on eight pixellated cadmium zinc telluride (CdZnTe) gamma-ray detector arrays. The detector is a 2.5 cm x 2.5 cm x 0.15 cm slab having a 64 x 64 pixel array. A read-out application-specific integrated circuit (ASIC) is attached onto the detector via indium-bump bonding, and a -180 V bias is applied onto the detector surface to transport electron-hole pairs generated by gamma-ray interaction. Eight detectors are arranged in an octagonal lead-shielded ring. An eight-pinhole aperture is placed at the center of the ring, and an object is imaged onto each detector through a pinhole. The object can be rotated about a vertical axis to attain sufficient angular projections for tomographic reconstruction. The whole system gantry is compact enough to be placed onto a desktop-sized optical breadboard. Eight front-end boards were developed to detect events, generate list-mode data arrays, and send them to back-end boards. Four back-end boards are utilized to hold the list-mode data arrays and transfer them to a host computer. Eight clock-and-bias boards provide clock and bias signals to the eight ASICs. Eight control-and-bias boards were developed to monitor and control the temperatures on the eight detectors, analog and digital currents supplied to the eight ASICs, and -180 V biases applied to the eight detector surfaces. The spatial resolution provided by SemiSPECT, estimated both based on the system geometry and via the Fourier crosstalk approach, is about 1˜2 mm. The system sensitivity measured with a point source is about 1.53 x 10-4, and the estimated one from the system geometry is about 1.41 x 10-4. The energy resolution acquired by summing neighboring pixel signals in a 3 x 3 window is about 10% full-width-at-half-maximum for 140 keV gamma rays. The detectabilities for multiple signal spheres simulating various lesions or organs in a small animal are presented and discussed. A line

  10. Attenuation correction effects on SPECT/CT procedures: phantoms studies.

    PubMed

    Oliveira, M L; Seren, M E G; Rocha, F C; Brunetto, S Q; Ramos, C D; Button, V L S N

    2013-01-01

    Attenuation correction is widely used in SPECT/CT (Single Photon Emission Computed Tomography) procedures, especially for imaging of the thorax region. Different compensation methods have been developed and introduced into clinical practice. Most of them use attenuation maps obtained using transmission scanning systems. However, this gives extra dose of radiation to the patient. The purpose of this study was to identify when attenuation correction is really important during SPECT/CT procedures.For this purpose, we used Jaszczak phantom and phantom with three line sources, filled with technetium ((99m)-Tc), with scattering materials, like air, water and acrylic, in different detectors configurations. In all images acquired were applied analytic and iterative reconstruction algorithms; the last one with or without attenuation correction. We analyzed parameters such as eccentricity, contrast and spatial resolution in the images.The best reconstruction algorithm on average was iterative, for images with 128 × 128 and 64 × 64 matrixes. The analytical algorithm was effective only to improve eccentricity in 64 × 64 matrix and matrix in contrast 128 × 128 with low statistics. Turning to the clinical routine examinations, on average, for 128 × 128 matrix and low statistics counting, the best algorithm was the iterative, without attenuation correction,improving in 150% the three parameters analyzed and, for the same matrix size, but with high statistical counting, iterative algorithm with attenuation correction was 25% better than that without correction. We can conclude that using the iterative algorithm with attenuation correction in the water, and its extra dose given, is not justified for the procedures of low statistic counting, being relevant only if the intention is to prioritize contrast in acquisitions with high statistic counting.

  11. Observer detection limits for a dedicated SPECT breast imaging system

    PubMed Central

    Cutler, S J; Perez, K L; Barnhart, H X; Tornai, M P

    2012-01-01

    An observer-based contrast-detail study is performed in an effort to evaluate the limits of object detectability using a dedicated CZT-based breast SPECT imaging system under various imaging conditions. A custom geometric contrast-resolution phantom was developed that can be used for both positive (‘hot’) and negative contrasts (‘cold’). The 3 cm long fillable tubes are arranged in six sectors having equal inner diameters ranging from 1 mm to 6 mm with plastic wall thicknesses of <0.25 mm, on a pitch of twice their inner diameters. Scans of the activity filled tubes using simple circular trajectories are obtained in a 215 mL uniform water filled cylinder, varying the rod:background concentration ratios from 10:1 to 1:10 simulating a large range of biological uptake ratios. The rod phantom is then placed inside a non-uniformly shaped 500 mL breast phantom and scans are again acquired using both simple and complex 3D trajectories for similarly varying contrasts. Summed slice and contiguous multi-slice images are evaluated by five independent readers, identifying the smallest distinguishable rod for each concentration and experimental setup. Linear and quadratic regression is used to compare the resulting contrast-detail curves. Results indicate that in a moderately low-noise 500 mL background, using the SPECT camera having 2.5 mm intrinsic pixels, the mean detectable rod was ~3.4 mm at a 10:1 ratio, degrading to ~5.2 mm with the 2.5:1 concentration ratio. The smallest object detail was observed using a 45° tilted trajectory acquisition. The complex 3D projected sine wave acquisition, however, had the most consistent combined intra- and inter-observer results, making it potentially the best imaging approach for consistent results. PMID:20224159

  12. Pharmacokinetics of SPECT radiopharmaceuticals for imaging hypoxic tissues.

    PubMed

    Wiebe, L I; Stypinski, D

    1996-09-01

    Although hypoxia has been known for decades to play an important role in the outcome of radiotherapy in oncology, and inspite of the contribution of hypoxia to a myriad of pathologies that involve vascular disease, the selective imaging of hypoxic tissue has attained prominence only within the past decade. Contemporary research in the hypoxia imaging field is based largely on radiosensitizer research of the 1960's and 1970's. Early sensitizer research identified a family of nitro-organic compounds, the N-1 substituted 2-nitroimidazoles as candidate drugs. The early champion, and still the reference standard for therapeutic radiosensitization of hypoxic tumor cells is misonidazole (MISO). Its peripheral neurotoxicity led to failure in clinical studies, but its biological, biophysical and biochemical properties have been investigated in detail and serve as a basis for further design, not only of sensitizers, but of diagnostic radiopharmaceuticals for imaging tissue hypoxia. Pharmacokinetic characterization of radiopharmaceuticals, specifically radiopharmaceuticals for imaging tissue hypoxia, has not been a central theme in their development. The advent of PET, through which quantitative determinations first became possible, opened the field for both descriptive and analytical radiopharmacokinetic studies. In SPECT, however, this approach is still undergoing refinement. This paper addresses some of the underlying issues in radiopharmaceutical pharmacokinetics. There is a paucity of published radiopharmacokinetic data for SPECT hypoxia imaging agents. Consequently, the pharmacokinetic issues for MISO are presented as a basis for development of pharmacokinetics for the chemically-related imaging agents. Properties of an hypoxia marker are described from a pharmacokinetic viewpoint, a theoretical model for descriptive pharmacokinetics is introduced and finally, recent pharmacokinetic studies from our laboratory are described.

  13. [Usefulness of SPECT images in helping radiologists understand brain diseases].

    PubMed

    Hayashida, K

    2001-04-01

    Nuclear brain imaging is able to show functional abnormalities of lesions that are not detectable by CT and MR images. The diagnostic keys of nuclear-imaging in terms of clinical usefulness are its early detection of lesions and determination of the efficacy of drug and surgical therapies. In dementic patients, F-18 FDG brain images can be diagnosed as Alzheimer's disease 12 months earlier than is possible on CT and MRI images, and can provide information for effective drug therapy. O-15 water CBF images can predict the effect of Nicholin by assessing transient increases in cerebral blood flow (CBF), thereby facilitating improvement in higher brain functions such as orientation. In stroke patients, brain SPECT images with Tc-99m HMPAO can predict fatal cerebral hemorrhage caused by anti-thrombic therapy by showing the decrease in count ratio (count ratio of infarcted to contralateral area of < 0.34) in the acute phase and identifying disruption of the blood brain barrier by showing hyperfixation in the subacute phase. Brain SPECT with I-123 IMP can also identify "misery" perfused areas resulting from reduced CBF and decreased vasoreactivity in the chronic phase. This criterion is utilized for patient selection for extracranial/intracranial bypass surgery, because patients with areas of poor perfusion might be indicated for such surgery. Since nuclear medicine images can accurately select candidates for drug or surgical therapies, they will be beneficial in reducing Medicare costs as well as in enhancing patients' quality of life as a result of the successful treatment. With the advancement of technology, nuclear medicine units that can simultaneously obtain CT images and can combine functional with anatomical images will provide more useful information for the diagnosis of brain disease.

  14. Multipinhole SPECT helical scan parameters and imaging volume.

    PubMed

    Yao, Rutao; Deng, Xiao; Wei, Qingyang; Dai, Tiantian; Ma, Tianyu; Lecomte, Roger

    2015-11-01

    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. 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 evaluated 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. 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. The authors quantitatively validated the effective FOV of multiple pinhole helical scan protocols and proposed a simple method to calculate optimal helical scan parameters.

  15. Multipinhole SPECT helical scan parameters and imaging volume

    SciTech Connect

    Yao, Rutao Deng, Xiao; Wei, Qingyang; Dai, Tiantian; Ma, Tianyu; Lecomte, Roger

    2015-11-15

    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 evaluated 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.

  16. Proceedings of the cardiac PET summit meeting 12 may 2014: Cardiac PET and SPECT instrumentation.

    PubMed

    Garcia, Ernest V

    2015-06-01

    Advances in PET and SPECT and imaging hardware and software are vastly improving the noninvasive evaluation of myocardial perfusion and function. PET perfusion imaging has benefitted from the introduction of novel detectors that now allow true 3D imaging, and precise attenuation correction (AC). These developments have also resulted in perfusion images with higher spatial and contrast resolution that may be acquired in shorter protocols and/or with less patient radiation exposure than traditional PET or SPECT studies. Hybrid PET/CT cameras utilize transmission computed tomographic (CT) scans for AC, and offer the additional clinical advantages of evaluating coronary calcium and myocardial anatomy but at a higher cost than PET scanners that use (68)Ge radioactive line sources. As cardiac PET systems continue to improve, dedicated cardiac SPECT systems are also undergoing a profound change in their design. The scintillation camera general purpose design is being replaced with systems with multiple detectors focused on the heart yielding 5 to 10 times the sensitivity of conventional SPECT. As a result, shorter acquisition times and/or lower tracer doses produce higher quality SPECT images than were possible before. This article reviews these concepts and compares the attributes of PET and SPECT instrumentation.

  17. Final Report: A CdZnTe detector for MRI-compatible SPECT Systems

    SciTech Connect

    Meng, Ling-Jian

    2012-12-27

    The key objective of this project is to develop the enabling technology for future MRI-compatible nuclear (e.g. SPECT) imaging system, and to demonstrate the feasibility of performing simultaneous MR and SPECT imaging studies of the same object. During the past three years, we have developed (a) a MRI-compatible ultrahigh resolution gamma ray detector and associated readout electronics, (b) a theoretical approach for modeling the effect of strong magnetic field on SPECT image quality, and (c) a maximum-likelihood (ML) based reconstruction routine with correction for the MR-induced distortion. With this support, we have also constructed a four-head MR-compatible SPECT system and tested the system inside a 3-T clinical MR-scanner located on UI campus. The experimental results obtained with this system have clearly demonstrated that sub-500um spatial resolution can be achieved with a SPECT system operated inside a 3-T MRI scanner. During the past three years, we have accomplished most of the major objectives outlined in the original proposal. These research efforts have laid out a solid foundation the development of future MR-compatible SPECT systems for both pre-clinical and clinical imaging applications.

  18. SPECT thallium-201 scintigraphy for the detection of left-ventricular aneurysm

    SciTech Connect

    Morton, K.A.; Alazraki, N.P.; Taylor, A.T.; Datz, F.L.

    1987-02-01

    We have noted that the presence of left ventricular anterior/apical aneurysm on contrast ventriculography or echocardiography correlates well with the finding of failure of convergence of the left ventricular walls toward the apex on single photon emission computed tomography (SPECT) thallium-201 images. To assess this observation, we analyzed the SPECT thallium scans of 74 sequential patients who had SPECT thallium scintigraphy and contrast ventriculography and/or echocardiography for evaluation of coronary artery disease. Immediate post-stress and 4-hr redistribution thallium-201 SPECT images, obtained following i.v. administration of 2 mCi of thallium-201, were reconstructed with no attenuation correction using three-dimensional linear and nonlinear filters and displayed in short, vertical-long, and horizontal-long axes. Of the 74 patients, contrast ventriculography and/or echocardiography showed anterior/apical aneurysms in 15 and a posterolateral aneurysm in one. SPECT thallium scans detected 14 of the 16 aneurysms, based on the criterion of failure of convergence of the ventricular walls toward the apex. There were two false-positives. Thus SPECT thallium-201 scintigraphy for the detection of left-ventricular aneurysm in this series had a sensitivity of 94%, a specificity of 97%, and an accuracy of 96%.

  19. [Current developments in SPECT/CT systems using 99mTc-radiopharmaceuticals].

    PubMed

    Ferro-Flores, Guillermina; de Murphy, Consuelo Arteaga

    2007-01-01

    The 3 foundations of nuclear medicine are radiation conscious personnel, specific radiopharmaceuticals and equipment. The trend in molecular radiopharmacy is to develop new radiopharmaceuticals targeting peptides and receptors. 99mTc-radiopharmaceuticals give important clinical and molecular information especially in endocrinology, oncology and cardiology. The basic equipment has relied on crystal scintillation detector gamma cameras and the obtained images represent organ function provided by the specific radiopharmaceutical. Gamma cameras for single emission computed tomography (SPECT) can be added to an X-ray computed tomography (CT) equipment to form a hybrid (SPECT/ CT). The system is coupled to computer algorithms and special software to acquire and process the separate studies and fuse the two images to give a 3-D image of organ function plus anatomy. The new semiconductor or solid state detectors are a big improvement in commercial hybrid scintillation cameras and micro-SPECT/CT. Fused images obtained with SPECT/CT have been very useful in almost all medical areas and play an important role in preclinical research. The aim of this work is to present the current status and future trends of SPECT/CT systems in the clinical practice of nuclear medicine using technetium-99m radiopharmaceuticals. The development of molecular, functional and genetic imaging tools aided by new technology and SPECT/CT image fusion will enhance accurate diagnoses, and understanding of molecular mechanisms of disease and their respective response to radiopharmaceutical therapy.

  20. SPECT attenuation correction: an essential tool to realize nuclear cardiology's manifest destiny.

    PubMed

    Garcia, Ernest V

    2007-01-01

    Single photon emission computed tomography (SPECT) myocardial perfusion imaging has attained widespread clinical acceptance as a standard of care for cardiac patients. Yet, physical phenomena degrade the accuracy of how our cardiac images are visually interpreted or quantitatively analyzed. This degradation results in cardiac images in which brightness or counts are not necessarily linear with tracer uptake or myocardial perfusion. Attenuation correction (AC) is a methodology that has evolved over the last 30 years to compensate for this degradation. Numerous AC clinical trials over the last 10 years have shown increased diagnostic accuracy over non-AC SPECT for detecting and localizing coronary artery disease, particularly for significantly increasing specificity and normalcy rate. This overwhelming evidence has prompted our professional societies to issue a joint position statement in 2004 recommending the use of AC to maximize SPECT diagnostic accuracy and clinical usefulness. Phantom and animal studies have convincingly shown how SPECT AC recovers the true regional myocardial activity concentration, while non-AC SPECT does not. Thus, AC is also an essential tool for extracting quantitative parameters from all types of cardiac radionuclide distributions, and plays an important role in establishing cardiac SPECT for flow, metabolic, innervation, and molecular imaging, our manifest destiny.

  1. Hybrid SPECT/CT Imaging in the Evaluation of Coronary Stenosis: Role in Diabetic Patients

    PubMed Central

    Romagnoli, Andrea; Schillaci, Orazio; Arganini, Chiara; Gaspari, Eleonora; Ricci, Aurora; Morosetti, Daniele; Coco, Irene; Crusco, Sonia; Calabria, Ferdinando; Sperandio, Massimiliano; Simonetti, Giovanni

    2013-01-01

    Purpose. Our purpose was to combine the results of the MDCT (multidetector computed tomography) morphological data and the SPECT (single-photon emission computed tomography) data using hybrid imaging to overcome the limits of the MDCT in the evaluation of coronary stenosis in diabetic patients with large amount of calcium in the coronary arteries. Method and Materials. 120 diabetic patients underwent MDCT examination and SPECT examination. We evaluated 324 coronary arteries. After the examinations, we merged CT and SPECT images. Results. CT evaluation: 52 (32.8%) coronaries with stenosis ≥ 50%, 228 (70.4%) with stenosis < 50%, and 44 (13.6%) with a doubtful evaluation. SPECT evaluation: 80 (24.7%) areas with hypoperfusion, 232 (71.6%) with normal perfusion, and 12 (3.7%) with a doubtful evaluation. Of 324 coronary arteries and corresponding areas, the hybrid SPECT/CT evaluation showed 92 (28.4%) areas with hypoperfusion, and 232 (71.6%) with normal perfusion. Conclusion. Hybrid CT/SPECT imaging could be useful in the detection of significant coronary stenosis in patients with large amount of coronary calcifications. PMID:24959556

  2. A Monte Carlo investigation of dual-planar circular-orbit cone-beam SPECT

    NASA Astrophysics Data System (ADS)

    Lalush, David S.; Di Meo, Andrew J.

    2002-12-01

    We use Monte Carlo simulations to study the imaging properties of a design for a dual-planar cone-beam (DPCB) single-photon emission computed tomography (SPECT) system. A dual-planar system uses a dual-camera SPECT system and two cone-beam collimators with foci in different axial planes to increase the effective axial field of view (FOV). We simulated nearly noise-free projection data from a computerized brain phantom and a phantom consisting of a series of points. Four configurations were simulated: parallel-beam low-energy high-resolution (LEHR) as a standard for comparison and DPCB at three radii of rotation (ROR) corresponding to the smallest, average and largest ROR required to clear patients' shoulders based on ergonomic data. We compared global measures of average resolution and total acquired counts for the four configurations. We also estimated local spatial frequency response for reconstructions of point sources. Finally, we estimated a local noise power spectrum by simulating 1000 noise realizations of the brain phantom and estimating a local noise covariance at selected points. The noise power spectra were used to estimate spectral signal to noise ratio (SNR) for each configuration. The resolution in the reconstructed image space ranges from 7.2 mm full-width at half-maximum (FWHM) at the minimum ROR to 9.4 mm FWHM at the maximum ROR. The efficiency is inversely related, ranging from 1.5 times that of parallel LEHR at minimum ROR to 2.5 times that of LEHR at maximum ROR. Estimates of system frequency response roughly correspond to the global resolution estimates, but the cone-beam techniques exhibit an unusual secondary peak in the axial-direction response. Estimates of spectral SNR show that the cone-beam configurations almost always result in higher SNR at all spatial frequencies regardless of ROR. The very largest ROR may be an exception. A larger ROR results in significantly higher SNR for low spatial frequencies with small reductions in SNR for mid

  3. Effect of reconstruction algorithms on the accuracy of 99mTc sestamibi SPECT/CT parathyroid imaging

    PubMed Central

    Nichols, Kenneth J; Tronco, Gene G; Palestro, Christopher J

    2015-01-01

    The superiority of SPECT/CT over SPECT for 99mTc-sestamibi parathyroid imaging often is assumed to be due to improved lesion localization provided by the anatomic component (computed tomography) of the examination. It also is possible that this superiority may be related to the algorithms used for SPECT data reconstruction. The objective of this investigation was to determine the effect of SPECT reconstruction algorithms on the accuracy of MIBI SPECT/CT parathyroid imaging. We retrospectively analyzed preoperative MIBI SPECT/CT parathyroid imaging studies performed on 106 patients. SPECT data were reconstructed by filtered back projection (FBP) and by iterative reconstruction with corrections for collimator resolution recovery and attenuation (IRC). Two experienced readers independently graded lesion detection certainty on a 5-point scale without knowledge of each other’s readings, reconstruction methods, other test results or final diagnoses. All patients had surgical confirmation of the final diagnosis, including disease limited to the neck, and location and weight of excised lesion(s). There were 135 parathyroid lesions among the 106 patients. For FBP SPECT/CT and IRC SPECT/CT sensitivity was 76% and 90% (p = 0.003), specificity was 87% and 87% (p = 0.90), and accuracy was 83% and 88% (p = 0.04), respectively. Inter-rater agreement was significantly higher for IRC than for FBP (kappa = 0.76, “good agreement”, versus kappa = 0.58, “moderate agreement”, p < 0.0001). We conclude that the improved accuracy of MIBI SPECT/CT compared to MIBI SPECT for preoperative parathyroid lesion localization is due in part to the use of IRC for SPECT data reconstruction. PMID:25973340

  4. Development and Optimization of a Dedicated, Hybrid Dual-Modality SPECT-CmT System for Improved Breast Lesion Diagnosis

    DTIC Science & Technology

    2008-01-01

    Dedicated, Hybrid Dual-Modality SPECT- CmT System for Improved Breast Lesion Diagnosis PRINCIPAL INVESTIGATOR: Priti Madhav...Development and Optimization of a Dedicated, Hybrid Dual-Modality SPECT- CmT System for Improved Breast Lesion Diagnosis 5b. GRANT NUMBER W81XWH-06...implement a dual-modality single photon emission computed tomography (SPECT) and x-ray computed mammotomography ( CmT ) system for the detection and

  5. High-Resolution SPECT-CT/MR Molecular Imaging of Angiogenesis in the Vx2 Model

    PubMed Central

    Lijowski, Michal; Caruthers, Shelton; Hu, Grace; Zhang, Huiying; Scott, Michael J.; Williams, Todd; Erpelding, Todd; Schmieder, Anne H.; Kiefer, Garry; Gulyas, Gyongyi; Athey, Phillip S.; Gaffney, Patrick J.; Wickline, Samuel A.; Lanza, Gregory M.

    2009-01-01

    Background The use of antiangiogenic therapy in conjunction with traditional chemotherapy is becoming increasingly in cancer management, but the optimal benefit of these targeted pharmaceuticals has been limited to a subset of the population treated. Improved imaging probes that permit sensitive detection and high-resolution characterization of tumor angiogenesis could improve patient risk-benefit stratification. Objectives The overarching objective of these experiments was to develop a dual modality αvβ3-targeted nanoparticle molecular imaging agent that affords sensitive nuclear detection in conjunction with high-resolution MR characterization of tumor angiogenesis. Materials and Methods In part 1, New Zealand white rabbits (n = 21) bearing 14d Vx2 tumor received either αvβ3-targeted 99mTc nanoparticles at doses of 11, 22, or 44 MBq/kg, nontargeted 99mTc nanoparticles at 22 MBq/kg, or αvβ3-targeted 99mTc nanoparticles (22 MBq/kg) competitively inhibited with unlabeled αvβ3-nanoparticles. All animals were imaged dynamically over 2 hours with a planar camera using a pinhole collimator. In part 2, the effectiveness of αvβ3-targeted 99mTc nanoparticles in the Vx2 rabbit model was demonstrated using clinical SPECT-CT imaging techniques. Next, MR functionality was incorporated into αvβ3-targeted 99mTc nanoparticles by inclusion of lipophilic gadolinium chelates into the outer phospholipid layer, and the concept of high sensitivity – high-resolution detection and characterization of tumor angiogenesis was shown using sequential SPECT-CT and MR molecular imaging with 3D neovascular mapping. Results αvβ3-Targeted 99mTc nanoparticles at 22 MBq/kg produced the highest tumor-to-muscle contrast ratio (8.56 ± 0.13, TMR) versus the 11MBq/kg (7.32 ± 0.12) and 44 MBq/kg (6.55 ± 0.07) doses, (P < 0.05). TMR of nontargeted particles at 22.2 MBq/kg (5.48 ± 0.09) was less (P < 0.05) than the equivalent dosage of αvβ3-targeted 99mTc nanoparticles. Competitively

  6. Applicability of a set of tomographic reconstruction algorithms for quantitative SPECT on irradiated nuclear fuel assemblies

    NASA Astrophysics Data System (ADS)

    Jacobsson Svärd, Staffan; Holcombe, Scott; Grape, Sophie

    2015-05-01

    A fuel assembly operated in a nuclear power plant typically contains 100-300 fuel rods, depending on fuel type, which become strongly radioactive during irradiation in the reactor core. For operational and security reasons, it is of interest to experimentally deduce rod-wise information from the fuel, preferably by means of non-destructive measurements. The tomographic SPECT technique offers such possibilities through its two-step application; (1) recording the gamma-ray flux distribution around the fuel assembly, and (2) reconstructing the assembly's internal source distribution, based on the recorded radiation field. In this paper, algorithms for performing the latter step and extracting quantitative relative rod-by-rod data are accounted for. As compared to application of SPECT in nuclear medicine, nuclear fuel assemblies present a much more heterogeneous distribution of internal attenuation to gamma radiation than the human body, typically with rods containing pellets of heavy uranium dioxide surrounded by cladding of a zirconium alloy placed in water or air. This inhomogeneity severely complicates the tomographic quantification of the rod-wise relative source content, and the deduction of conclusive data requires detailed modelling of the attenuation to be introduced in the reconstructions. However, as shown in this paper, simplified models may still produce valuable information about the fuel. Here, a set of reconstruction algorithms for SPECT on nuclear fuel assemblies are described and discussed in terms of their quantitative performance for two applications; verification of fuel assemblies' completeness in nuclear safeguards, and rod-wise fuel characterization. It is argued that a request not to base the former assessment on any a priori information brings constraints to which reconstruction methods that may be used in that case, whereas the use of a priori information on geometry and material content enables highly accurate quantitative assessment, which

  7. 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

  8. The influence of a relaxation parameter on SPECT iterative reconstruction algorithms.

    PubMed

    Ros, D; Falcón, C; Juvells, I; Pavía, J

    1996-05-01

    Algebraic reconstruction techniques (ARTs) have been intensively studied in image reconstruction. However, reconstructed images often exhibit a characteristic noise when applied to emission tomography. In this work, we study the influence of the ART relaxation parameter and identify values of that parameter which yield smooth images and good convergence. The study includes both simulated and real single photon emission computed tomographic (SPECT) data. In the simulated studies, scattering, attenuation, noise and detector response were included. Relaxation factors ranging between 0.01 and 0.35 were considered. Total counts in projections were between 2.5 x 10(5) and 10(6) in one slice. The goodness of the reconstructions was assessed by using the correlation coefficient between the pattern and the actual reconstruction (CC), the background coefficient of variation (CV), the contrast (CON) and the signal-to-noise ratio (SNR). The results show that values for the relaxation factor and number of interations close to 0.1 and 8, respectively, yield reconstructed images in which CC, CV, CON and SNR have well balanced values and CC, CV and SNR are very close to the extremal. An increase in either the number of iterations or in the relaxation factor results in a rise of CON but the other three FOMs deteriorate. The results from the real phantom, which are in agreement with those of the simulated studies, validate the simulation method and demonstrate the influence of the relaxation parameter.

  9. Usefulness of scintigraphy with labelled leucocytes and SPECT/CT in vascular graft infection.

    PubMed

    Marín-Oyaga, V; Gutierrez-Villamil, C; García-Concha, D; Arevalo-Leal, S

    2017-06-12

    Vascular graft infections are a rare complication in this type of procedure. However, when they do occur, they usually have high morbidity, and even a high mortality. Proper identification and location is crucial for the appropriate and early management, whether medical or surgical, thus knowledge of the right tools is paramount. Nuclear medicine studies play an important role in this regard, either by using labelled white blood cells scintigraphy or (18)F-FDG. The choice, among other factors, will depend on the experience with both techniques by the different groups, their knowledge of them, as well as their availability. Two cases are presented in which (99m)Tc-HMPAO-white blood cells SPECT/CT scintigraphy was very useful in the diagnosis and location of the suspected infectious compromise, which led to the subsequent appropriate and guided management. Both cases were confirmed clinically and microbiologically. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  10. A flexible high-rate USB2 data acquisition system for PET and SPECT imaging

    SciTech Connect

    J. Proffitt, W. Hammond, S. Majewski, V. Popov, R.R. Raylman, A.G. Weisenberger, R. Wojcik

    2006-02-01

    A new flexible data acquisition system has been developed to instrument gamma-ray imaging detectors designed by the Jefferson Lab Detector and Imaging Group. Hardware consists of 16-channel data acquisition modules installed on USB2 carrier boards. Carriers have been designed to accept one, two, and four modules. Application trigger rate and channel density determines the number of acquisition boards and readout computers used. Each channel has an independent trigger, gated integrator and a 2.5 MHz 12-bit ADC. Each module has an FPGA for analog control and signal processing. Processing includes a 5 ns 40-bit trigger time stamp and programmable triggering, gating, ADC timing, offset and gain correction, charge and pulse-width discrimination, sparsification, event counting, and event assembly. The carrier manages global triggering and transfers module data to a USB buffer. High-granularity time-stamped triggering is suitable for modular detectors. Time stamped events permit dynamic studies, complex offline event assembly, and high-rate distributed data acquisition. A sustained USB data rate of 20 Mbytes/s, a sustained trigger rate of 300 kHz for 32 channels, and a peak trigger rate of 2.5 MHz to FIFO memory were achieved. Different trigger, gating, processing, and event assembly techniques were explored. Target applications include >100 kHz coincidence rate PET detectors, dynamic SPECT detectors, miniature and portable gamma detectors for small-animal and clinical use.

  11. Analysis of SPECT brain images for the diagnosis of Alzheimer's disease using moments and support vector machines.

    PubMed

    Salas-Gonzalez, Diego; Górriz, Juan M; Ramírez, Javier; López, Miriam; Illan, Ignacio A; Segovia, Fermín; Puntonet, Carlos G; Gómez-Río, Manuel

    2009-09-11

    This paper presents a computer-aided diagnosis technique for improving the accuracy of diagnosing the Alzheimer's type dementia. The proposed methodology is based on the calculation of the skewness for each m-by-m-by-m sliding block of the SPECT brain images. The center pixel in this m-by-m-by-m block is replaced by the skewness value to build a new 3-D brain image which is used for classification purposes. After that, voxels which present a Welch's t-statistic between classes, Normal and Alzheimer's images, higher (or lower) than a threshold are selected. The mean, standard deviation, skewness and kurtosis are calculated for these selected voxels and they are subjected as features to linear kernel based support vector machine classifier. The proposed methodology reaches accuracy higher than 99% in the classification task.

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

    PubMed Central

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

    2010-01-01

    We have designed a multi-pinhole collimator for a dual-headed, stationary SPECT system that incorporates high-resolution silicon double-sided strip detectors. The compact camera design of our system enables imaging at source–collimator distances between 20 and 30 mm. Our analytical calculations show that using knife-edge pinholes with small-opening angles or cylindrically shaped pinholes in a focused, multi-pinhole configuration in combination with this camera geometry can generate narrow sensitivity profiles across the field of view that can be useful for imaging small objects at high sensitivity and resolution. The current prototype system uses two collimators each containing 127 cylindrically shaped pinholes that are focused toward a target volume. Our goal is imaging objects such as a mouse brain, which could find potential applications in molecular imaging. PMID:19088387

  13. CT ventilation functional image-based IMRT treatment plans are comparable to SPECT ventilation functional image-based plans.

    PubMed

    Kida, Satoshi; Bal, Matthieu; Kabus, Sven; Negahdar, Mohammadreza; Shan, Xin; Loo, Billy W; Keall, Paul J; Yamamoto, Tokihiro

    2016-03-01

    To investigate the hypothesis that CT ventilation functional image-based IMRT plans designed to avoid irradiating highly-functional lung regions are comparable to single-photon emission CT (SPECT) ventilation functional image-based plans. Three IMRT plans were created for eight thoracic cancer patients using: (1) CT ventilation functional images, (2) SPECT ventilation functional images, and (3) anatomic images (no functional images). CT ventilation images were created by deformable image registration of 4D-CT image data sets and quantitative analysis. The resulting plans were analyzed for the relationship between the deviations of CT-functional plan metrics from anatomic plan metrics (ΔCT-anatomic) and those of SPECT-functional plans (ΔSPECT-anatomic), and moreover for agreements of various metrics between the CT-functional and SPECT-functional plans. The relationship between ΔCT-anatomic and ΔSPECT-anatomic was strong (e.g., R=0.94; linear regression slope 0.71). The average differences and 95% limits of agreement between the CT-functional and SPECT-functional plan metrics (except for monitor units) for various structures were mostly less than 1% and 2%, respectively. This study demonstrated a reasonable agreement between the CT ventilation functional image-based IMRT plans and SPECT-functional plans, suggesting the potential for CT ventilation imaging to serve as a surrogate for SPECT ventilation in functional image-guided radiotherapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

    SciTech Connect

    LaManna, M.M.; Sussman, N.M.; Harner, R.N.; Kaplan, L.R.; Hershey, B.L.; Bernstein, D.R.; Goldstein, P.; Parker, J.A.; Wolodzko, J.G.; Popky, G.L.

    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.

  15. Multimodality imaging techniques.

    PubMed

    Martí-Bonmatí, Luis; Sopena, Ramón; Bartumeus, Paula; Sopena, Pablo

    2010-01-01

    In multimoda