Photon Emission Computed Tomography Imaging Research Articles

Evaluation of Acceptance Angle in Iodine-131 Single Photon Emission Computed Tomography Imaging with Monte Carlo Simulation.

Introduction:In iodine-131 (I-131) imaging, the image quality is degraded by scatter and penetration in a collimator. In this work, we assessed the penetrated and the scattered photon fractions in the photopeak energy window using Monte Carlo Simulation code.Materials and Methods:The Siemens Medical System equipped with high-energy collimator was simulated. We evaluated the acceptance angle values on geometric, penetration, and scatter components in a separate file. Binary images in a data file are obtained and each one of them was imported in software ImageJ. Full-width at half-maximum (FWHM) and sensitivity were calculated and compared.Results:The simulation data show that for the acceptance angle value equal to 4.845°, the geometric, scatter, and penetration components were 93.20%, 4.13%, and 2.67%, respectively. Moreover, the resolution is improved (FWHM = 7.21 mm, full width at tenth maximum = 12.36 mm) for a point source at 12 cm from the detector.Conclusion:The small acceptance angle has a major impact on the image quality in I-131 single photon emission computed tomography.

Assessment of viable myocardium by nitrate-augmented technetium-99m sestamibi myocardial perfusion imaging

Objective The aim of this study was to assess the role of nitrate-augmented technetium-99m (99mTc) sestamibi imaging in the evaluation of viable myocardium in patients who had ischemic heart disease with depressed left ventricle (LV) systolic function. Background In the setting of acute myocardial infarction, stunning can occur, which is the persistent LV dysfunction following opening of the occluded coronary artery; recovery of function occurs usually within months. In the setting of chronic LV dysfunction, the pathophysiology underlying the dysfunction is referred to as myocardial hibernation. Various imaging techniques have been introduced to detect viability and discriminate this from scar tissue. Patients and methods Between November 2015 and November 2016, 100 patients with a history of myocardial infarction 'functional class II and III' or/and LV dysfunction were included in this multicenter prospective study. All patients underwent 99mTc sestamibi myocardial perfusion imaging under both rest and rest with nitrate conditions. Results Nitrates improved viability detection by myocardial perfusion imaging in patients with depressed LV systolic function. There was significant decrease in the total perfusion defect in rest with nitrate study in comparison with the rest study (P = 0.006). Conclusion In patients with chronic ischemic heart disease with depressed LV systolic function, the use of nitrate-augmented Tc-99m sestamibi protocol in cardiac single photon emission computed tomography imaging results in improved detection of viable but hypoperfused segments. It is a good indicator for differentiating viable tissues from the scar.

Usefulness of single photon emission computed tomography imaging in identifying target dystonic muscles in patients with cervical dystonia

Usefulness of single photon emission computed tomography imaging in identifying target dystonic muscles in patients with cervical dystonia

Optimization of a SPECT system for imaging of 90Y in liver using Monte Carlo method

Introduction: Acquiring a high quality image has assigned an important concern for obtaining accurate diagnosis in nuclear medicine. Detector and collimator are critical component of Single Photon Emission Computed Tomography (SPECT) imaging system for giving accurate information from exact pattern of radionuclide distribution in the target organ. The images are strongly affected by the attenuation, scattering, and response of the detector and collimator. Method and material: The Planar and SPECT scans of a Y90 point source and also an extended Cardiac- Torso(XCAT) computerized phantom with the experiment and simulated systems were prepared. The SIMIND Monte Carlo program was used for simulating Siemen’s dual head variable angle SPECT imaging system with 4 detectors and 10 collimators. After verification and validation of the simulated system, the similar scans of the phantoms were compared from the point of view of image quality for 4 scintillator crystals including: NaI(Tl), BGO, LuAG: Ce, LaBr3 and also 10 collimators: Pb, Pb-Sb, Pb-Sb3, Pb-bi-Sn19, Pb-bi Sn375, Pb-bi-Sn50, Pb-bi-Sn-cd10, Pb-bi-Sn-cd125, Pt and Pt-Co. The parameters of energy and spatial resolution, and sensitivity of the systems were compared. Images were analyzed qualitatively by two nuclear medicine specialists. RESULTS: FWHM of the mentioned crystals and collimators obtained where: NaI (Pb, 0.3853) and BGO (Pb-Sb, 0.406), (Pb-Bi-Sn375, 0.405), (Pb-Bi-Sn-cd125, 0.375), and LuAG: Ce crystal (Pb-Sb, 0.425), (Pb- Bi-Sn19, 0.407), (Pb-Bi-Sn375, 0.417) and also LaBr3 (Pb-Bi-Sn375, 0.407), (Pb-Bi-Sn50, 0.430), (Pt-Co, 0.355). Medical diagnosis of the SPECT images of the phantom showed that the system with NaI(Tl)and LaBr3 by Pb-Sn3 collimator potentially provides a better detectability for hot lesions in the liver of XCAT phantom. CONCLUSIONS: The results showed that crystal NaI(Tl)and LaBr3 by Pb-Sn3 collimator has a high sensitivity and resolution, and also provides a better lesion detectability from the point of view of image quality on XCAT phantom.

Effect of hyperbaric oxygen therapy on chronic neurocognitive deficits of post-traumatic brain injury patients: retrospective analysis

ObjectivesThe aim of the study is to evaluate the effect of hyperbaric oxygen therapy (HBOT) in participants suffering from chronic neurological deficits due to traumatic brain injury (TBI) of all...

Clinical value of single photon emission computed tomography imaging in differential diagnosis of neonatal obstructive jaundice

Objective To investigate and explore the clinical value of single-photon emission computed tomography(SPECT) imaging in the differential diagnosis of neonatal obstructive jaundice. Methods From January 2012 to April 2017, 130 cases of suspected neonatal obstructive jaundice in the First Hospital of Jiaxing were enrolled in the study.All patients were given SPECT hepatobiliary scintigraphy, were injected 99mTc-EHIDA imaging agent, 99mTc-MIBI imaging agent, diagnosis of hepatobiliary scintigraphy after the acquisition.The result of operative cholangiography was viewed as the gold standard, the diagnostic sensitivity, specificity, accuracy of simple 99mTc-EHIDA SPECT imaging examination, combined with SPECT imaging agent in the diagnosis of neonatal obstructive jaundice were calculated and compared.The coincidence rate of differential diagnosis of different etiologies of neonatal obstructive jaundice was also compared. Results The diagnostic sensitivity, specificity and accuracy of combined with SPECT imaging agent in the diagnosis of neonatal obstructive jaundice were 94.23%, 96.15%, 94.61%, respectively, which of simple 99mTc-EHIDA imaging agent SPECT were 83.65%, 76.92%, 82.31%, respectively, the differences were statistically significant(χ2=5.915, 4.127, 9.646, all P<0.05). The coincidence rates of extrahepatic biliary atresia, hepatitis syndrome of the two kinds of SPECT imaging agents combined examination were 96.05%, 96.43%, respectively, which were significantly higher than those of the 99mTc-EHIDA imaging agent SPECT examination (84.21%, 85.00%)(χ2=5.991, 5.250, all P<0.05). Conclusion SPECT imaging in the diagnosis of neonatal obstructive jaundice has high sensitivity and accuracy, especially in combination with 99mTc-EHIDA imaging agent, 99mTc-MIBI imaging agent can identify and distinguish different causes of jaundice, and provide a reliable basis for clinical treatment. Key words: Jaundice, neonatal; Jaundice, obstructive; Diagnosis; Single-photon emission computed tomography

An 18F-Labeled Poly(ADP-ribose) Polymerase Positron Emission Tomography Imaging Agent.

Poly(ADP-ribose) polymerase (PARP) is involved in repair of DNA breaks and is over-expressed in a wide variety of tumors, making PARP an attractive biomarker for positron emission tomography (PET) and single photon emission computed tomography imaging. Consequently, over the past decade, there has been a drive to develop nuclear imaging agents targeting PARP. Here, we report the discovery of a PET tracer that is based on the potent PARP inhibitor olaparib (1). Our lead PET tracer candidate, [18F]20, was synthesized and evaluated as a potential PARP PET radiotracer in mice bearing subcutaneous glioblastoma xenografts using ex vivo biodistribution and PET–magnetic resonance imaging techniques. Results showed that [18F]20 could be produced in a good radioactivity yield and exhibited specific PARP binding allowing visualization of tumors over-expressing PARP. [18F]20 is therefore a potential candidate radiotracer for in vivo PARP PET imaging.

Progression of tremor in early stages of Parkinson's disease: a clinical and neuroimaging study.

Rest tremor is one of the cardinal signs of Parkinson's disease. Kinetic and postural tremors may also occur. The coexistence of these three types of tremor at disease onset and their subsequent progression could have important clinical and therapeutic implications but remain to be fully elucidated. We aimed to: (i) evaluate prevalence and progression of these three types of tremor in early stages of the disease; and (ii) investigate longitudinally the relationship between dopaminergic and serotonergic terminal dysfunction, rest tremor severity and its response to dopaminergic therapy. The Parkinson's Progressive Markers Initiative database provided the baseline and 2-year follow-up clinical ratings and 123ioflupane-fluoropropyl-carbomethoxy-3-beta-4-iodophenyltropane (123I-FP-CIT) single photon emission computed tomography images for this study. 123I-FP-CIT measured putamen dopamine transporter and median raphe serotonin transporter availability. A raphe/putamen uptake ratio was calculated for each patient as an index of relative involvement of these structures. Clinical analysis of tremor was conducted on 378 patients: 87.8% presented with tremor at baseline; rest tremor occurred in 69.6% of patients at baseline; and 67.9% at follow-up. Postural and kinetic tremors occurred in about 50% of patients at both baseline and follow-up. Over 20% of patients presenting with tremor did not exhibit a rest component at baseline. The number of patients with isolated rest tremor was halved at follow-up. In tremor predominant patients, rest tremor severity was inversely correlated with raphe serotonin transporter availability both at baseline and follow-up (baseline: constancy P < 0.05, tremor index P < 0.05; follow-up: amplitude P < 0.05, constancy P < 0.05, tremor index P < 0.05). In the entire cohort, more severe tremor scores correlated with lower raphe/putamen uptake ratio values, indicative of more severe raphe dysfunction (baseline: constancy P < 0.01, tremor index P < 0.05; follow-up: amplitude P < 0.01, constancy P < 0.001, tremor index P < 0.001). The percentage of improvement in rest tremor amplitude after acute dopaminergic therapy was smaller in patients with lower raphe/putamen uptake ratio values (P < 0.01). Rest tremor is the most represented type of tremor in early Parkinson's disease. However, postural and kinetic tremor can affect approximately half of these patients and can occur in absence of resting tremor. As disease progresses, both raphe serotonergic dysfunction and putamen dopamine depletion could contribute to the occurrence of rest tremor. The former is linked to more severe tremor scores and poorer response to dopaminergic therapy. Non-dopaminergic treatments might be beneficial for patients whose tremor is associated with a raphe-predominant dysfunction.

The subresolution DaTSCAN phantom: a cost-effective, flexible alternative to traditional phantom technology.

The Alderson striatal phantom is frequently used to assess I-FP-CIT (Ioflupane) image quality and to test semi-quantification software. However, its design is associated with a number of limitations, in particular: unrealistic image appearances and inflexibility. A new physical phantom approach is proposed on the basis of subresolution phantom technology. The design incorporates thin slabs of attenuating material generated through additive manufacturing, and paper sheets with radioactive ink patterns printed on their surface, created with a conventional inkjet printer. The paper sheets and attenuating slabs are interleaved before scanning. Use of thin layers ensures that they cannot be individually resolved on reconstructed images. An investigation was carried out to demonstrate the performance of such a phantom in producing simplified I-FP-CIT uptake patterns. Single photon emission computed tomography imaging was carried out on an assembled phantom designed to mimic a healthy patient. Striatal binding ratio results and linear striatal dimensions were calculated from the reconstructed data and compared with that of 22 clinical patients without evidence of Parkinsonian syndrome, determined from clinical follow-up. Striatal binding ratio results for the fully assembled phantom were: 3.1, 3.3, 2.9 and 2.6 for the right caudate, left caudate, right putamen and right caudate, respectively. All were within two SDs of results derived from a cohort of clinical patients. Medial-lateral and anterior-posterior dimensions of the simulated striata were also within the range of values seen in clinical data. This work provides the foundation for the generation of a range of more clinically realistic, physical phantoms.

Novel 99mTc-labelled complexes with thymidine isocyanide: radiosynthesis and evaluation as potential tumor imaging tracers.

A novel thymidine isocyanide (CN-TdR) functionalized at the N3 position of thymidine was synthesized and then radiolabelled with 99mTc(i) and [99mTc(i)(CO)3]+ cores to produce [99mTc(CN-TdR)6]+ and [99mTc(CO)3(CN-TdR)3]+, respectively. Both of them were prepared with high radiochemical purity and were stable over 6 h in saline at ambient temperature and in serum at 37 °C. The partition coefficient results demonstrated that they were hydrophilic. The cell internalization studies showed that their uptake might be mediated by nucleoside transporters. Biodistribution of these complexes in mice bearing the S180 tumor showed that they accumulated in the tumor with high uptake and cleared rapidly from blood and muscles, producing high tumor/blood and tumor/muscle ratios. Between them, [99mTc(CN-TdR)6]+ exhibited advantages concerning a higher tumor uptake, tumor/blood ratio and tumor/muscle ratio at 60 min post-injection. Single photon emission computed tomography imaging studies showed that there was a clear accumulation in tumor sites, suggesting that [99mTc(CN-TdR)6]+ could be a promising candidate for tumor imaging.

Changing Landscapes in the Neuroimaging of Dementia.

Neuroimaging in dementia has advanced several folds in the past decade. It has evolved from diagnosing secondary causes of dementia to the current use in identifying primary dementia and aid in clinically perplexing situations. There has been a leap in the imaging technology that can virtually dissect the brain with a high degree of radiopathological correlation. The neuroimaging in dementia is classified into structural, functional, and molecular imaging. Structural imaging includes voxel-based morphometry and diffusion tensor imaging. Functional imaging includes 18F-fluorodeoxy glucose positron emission tomography imaging, 99mTc hexamethylpropyleneamineoxime single photon emission computed tomography imaging, and functional magnetic resonance imaging studies. Molecular imaging includes amyloid imaging, tau imaging, and translocated protein imaging. These advancements have led to using neuroimaging as a biomarker in assessing the progression and also in deciphering prognosis of the disease. In this article, we discuss the current clinical relevance of these neurological advancements.

Navigation of Fluorescence Cameras during Soft Tissue Surgery—Is it Possible to Use a Single Navigation Setup for Various Open and Laparoscopic Urological Surgery Applications?

Real-time visualization fluorescence imaging can guide surgeons during tissue resection. Unfortunately tissue induced signal attenuation limits the value of this technique to superficial applications. By positioning the fluorescence camera via a dedicated navigation setup we reasoned that the technology could be made compatible with deeper lesions, increasing its impact on clinical care. Such an impact would benefit from the ability to implement the navigation technology in different surgical settings. For that reason we evaluated whether a single fluorescence camera could be navigated toward targeted lesions during open and laparoscopic surgery. A fluorescence camera with scopes available for open and laparoscopic procedures was integrated with a navigation platform. Lymph nodes identified on SPECT/CT (single photon emission computerized tomography/computerized tomography) or free-hand single photon emission computerized tomography acted as navigation targets and were displayed as augmented overlays in the fluorescence camera video feed. The accuracy of this setup was evaluated in a phantom study of 4 scans per single photon emission computerized tomography imaging modality. This was followed by 4 first in human translations into sentinel lymph node biopsy procedures for penile (open surgery) and prostate (laparoscopic surgery) cancer. Overall the phantom studies revealed a tool-target distance accuracy of 2.1 mm for SPECT/CT and 3.2 mm for freehand single photon emission computerized tomography, and an augmented reality registration accuracy of 1.1 and 2.2 mm, respectively. Subsequently open and laparoscopic navigation efforts were accurate enough to localize the fluorescence signals of the targeted tissues invivo. The phantom and human studies performed suggested that the single navigation setup is applicable in various open and laparoscopic urological surgery applications. Further evaluation in larger patient groups with a greater variety of malignancies is recommended to strengthen these results.

Synthesis and evaluation of a novel 99mTc nitrido radiopharmaceutical with alendronate dithiocarbamate as a potential bone‐imaging agent

Currently, a popular strategy for designing novel radioprobes as bone-imaging agents is based on the concept of bifunctional radiopharmaceuticals. Considering the dithiocarbamate ligand can act as a suitable bifunctional linking agent to attach technetium-99m (99m Tc) to corresponding target molecules, in this study, alendronate dithiocarbamate (ALNDTC) was synthesized and radiolabeled with [99m Tc≡N]2+ core by ligand exchange reaction to produce 99m TcN-ALNDTC complex, for the potential use as a novel probe for bone imaging. The radiochemical purity of the complex was over 90%. The complex was stable in vitro and could bind to hydroxyapatite. The partition coefficient result indicated it was hydrophilic, and an evaluation of biodistribution in mice indicated that the complex exhibited a higher bone uptake than did 99m Tc-labeled methylenediphosphonate (99m Tc-MDP). Further, single photon emission computed tomography imaging study indicated clear accumulation in bone, suggesting that 99m TcN-ALNDTC would be a promising candidate for bone imaging.

A migration case of Kii amyotrophic lateral sclerosis/parkinsonism dementia complex with the shortest stay in the endemic area and the longest incubation to develop the disease

Amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC) is an endemic disease observed in the Kii peninsula, Guam, and Papua. We report a case of a 76-year old man with ALS/PDC of the Kii peninsula of Japan (Kii ALS/PDC). The patient was born and grew up in the Kii peninsula. He moved out at age three, and developed symptoms 73years later. He showed pyramidal sign, parkinsonian symptoms, and mildly impaired cognitive function. 131I-metaiodobenzylguanidine myocardial scintigraphy showed decreased cardiac sympathetic nerve function, and dopamine transporter single photon emission computed tomography imaging showed decreased 123I-N-ω-fluoropropyl-2β-carbomethoxy3β-(4-iodophenyl) nortropane accumulation. Cerebral blood flow showed hypoperfusion. Positron emission tomography showed widespread tau deposition in his brain. This is a migration case of Kii ALS/PDC with the shortest stay in the endemic area and the longest delay to develop the disease, indicating a genetic factor for the disease development in a considerable degree.

The recovery of the renal function in the severe hydronephrosis children after percutaneous nephrostomy

Objective To analyze the recovery of the renal function in the severe hydronephrosis children after percutaneous nephrostomy. Methods 50 cases of uretero-pelvic junction obstruction (UPJO) children were retrospectively studied from January 2013 to January 2016. There were 25 boys and 25 girls, and the mean age was 3.0 years (ranged from 2 months to 9 years and 7 months). The children were taken the percutaneous nephrostomy in the first stage and pyeloplasty or nephrectomy in the second stage according to the recovery of renal function. Split renal function, urine osmotic pressure, urine pH and urine β2-microglobulin (β2-MG) were compared between pre-operation and post-operation. The recovery of the renal function after the operation were evaluated by the single photon emission computed tomography (SPECT) and superb micro-vascular imaging (SMI) to analysis the feasibility of the pyeloplasty surgery in the severe hydronephrosis children. Result The postoperative renal function of 49 patients in the group recovered after percutaneous nephrostomy, only one child showed unrecoverable. After the first stage management, the renal cortical thickness [(5.9±1.0) mm vs. (2.9±0.9) mm, P=0.03], the separate renal function [(25.7%±7.9% ) vs. (13. 5%±5.2 %), P=0.007] and urine osmotic pressure [(518.0±240.0) mmol/L vs. (126.5±100.5) mmol/L, P<0.001] were significantly improved compared with pre-operation, and RI [(0.72±0.03) vs. (0.79±0.04), P=0.021], urine pH [(6.18±0.21) vs. (7.38±0.32), P=0.039] and urine β2-MG [(562.16±49.78) mg/L vs. (954.28±69.45) mg/L, P<0.001] significantly reduced. Conclusions The renal function of the severe hydronephrosis children could be recoverable after the surgery of the percutaneous nephrostomy and pyeloplasty. Most children′s kidneys suffered the severe hydronephrosis could be spared by surgery. SMI technology could provide reliable quantitative basis to evaluate renal function. Key words: Hydronephrosis, severe; Pyeloplasty; Renal function; Pediatric

The EXERRT trial: “EXErcise to Regadenoson in Recovery Trial”: A phase 3b, open-label, parallel group, randomized, multicenter study to assess regadenoson administration following an inadequate exercise stress test as compared to regadenoson without exercise for myocardial perfusion imaging using a SPECT protocol

BackgroundThis study assessed the non-inferiority and safety of regadenoson administration during recovery from inadequate exercise compared with administration without exercise. MethodsPatients unable to achieve adequate exercise stress were randomized to regadenoson 0.4 mg either during recovery (Ex-Reg) or 1 hour after inadequate exercise (Regadenoson) (MPI1). All patients also underwent non-exercise regadenoson MPI 1-14 days later (MPI2). The number of segments with reversible perfusion defects (RPDs) detected using single photon emission computerized tomography imaging was categorized. The primary analysis evaluated the majority agreement rate between Ex-Reg and Regadenoson groups. Results1,147 patients were randomized. The lower bound of the 95% confidence interval of the difference in agreement rates (−6%) was above the −7.5% non-inferiority margin, demonstrating non-inferiority of Ex-Reg to Regadenoson. Adverse events were numerically less with Ex-Reg (MPI1). In the Ex-Reg group, one patient developed an acute coronary syndrome and another had a myocardial infarction following regadenoson after exercise. Upon review, both had electrocardiographic changes consistent with ischemia prior to regadenoson. ConclusionsAdministering regadenoson during recovery from inadequate exercise results in comparable categorization of segments with RPDs and with careful monitoring appears to be well tolerated in patients without signs/symptoms of ischemia during exercise and recovery.

Hybrid Bone Single Photon Emission Computed Tomography Imaging in Evaluation of Chronic Low Back Pain: Correlation with Modic Changes and Degenerative Disc Disease.

Multiple radiologic modalities are used in the evaluation of patients with low back pain (LBP). Only limited evidence currently exists to support the use of bone hydroxydiphosphonate single photon emission computed tomography (SPECT/CT) in patients with Modic changes (MCs) and degenerative disc disease. The aim of this study was to assess the value of the hybrid bone SPECT/CT imaging in patients with chronic LBP. We evaluate the correlation of hybrid bone SPECT/CT imaging patterns with MCs and disc abnormalities on magnetic resonance imaging (MRI). This was a prospective study. Ninety-nine consecutive patients with LBP from a single center. The degree of lumbar intervertebral disc and endplate degeneration on MRI and osteoblastic activity was shown on SPECT/CT. These 99 consecutive patients with LBP were prospectively evaluated. Patients with contemporary lumbosacral spine MRI and bone SPECT/CT were included. Patients with known or suspected malignancy, trauma, infectious processes, and previous surgery were excluded. The effect of LBP on the daily quality of life was assessed using Oswestry disability index. We analyzed the correlation between the degenerative changes at the intervertebral disc spaces and endplates on MRI and bone SPECT/CT findings using receiver operating characteristic curve analysis and Kappa statistics. The Pfirrmann grading system was used to score the severity of disc space degeneration on MRI scans. A total of 99 patients were included in the study (58 women, 41 men; mean age, 56.2 years). Mean Oswestry disability index score was 38.5% (range, 8%-72%). The L2-3 through to L5-S1 levels were studied. MCs were found in 54% of patients. Of the 396 levels examined 85 were found to have MCs (21.5%). The most affected levels were L4-5 (31.3%) and L5-S1 (40.9%). Pfirrmann grade 5 disc space (72.9%) was associated with MC (Pp<0.001). MC (70.6%) and Pfirrmann grade 5 disc spaces (73%) resulted in scintigraphically active endplate/disc space on SPECT/CT (P< 0.001). Bone SPECT/CT showed high metabolic activity in 96.1% of endplates with MC type I, 56% with MC type II, and 77.8% with MC type III. In this study we found a high agreement between MCs and increased metabolic activity on bone SPECT/CT imaging. MC type 1 and Pfirrmann grade 5 were the best binary predictors for positivity on bone SPECT/CT and had equivalent correlations. Lower vertebral levels in the lumbar spine were associated with higher degree of disc degeneration, high frequency of MCs, and positivity on bone SPECT/CT.

The Optimization of the Single Photon Emission Computed Tomography Image Quality via Taguchi Analysis: A Feasibility Study of a V-Shaped Phantom

The Optimization of the Single Photon Emission Computed Tomography Image Quality via Taguchi Analysis: A Feasibility Study of a V-Shaped Phantom

Assessment of the scatter correction procedures in single photon emission computed tomography imaging using simulation and clinical study

Compton-scattered photons transfer incorrect spatial information. These photons are detected in used photo-peak energy window. In this study, three scatter correction procedures including dual-energy window (DEW), three energy window (TEW), and new approach were evaluated, and then the best procedure based on simulation and clinical conditions introduced. In this study, simulation projections and three-dimensional nonuniform rational B-spline-based Cardiac-Torso phantoms were produced by GEANT4 application for emission tomography simulation code. For clinical study, 2-day stress/rest myocardial perfusion imaging (MPI) protocol was performed with 99m Tc-sestamibi for 46 patients. Image quality parameters including contrast, signal-to-noise ratio (SNR), and relative noise of the background (RNB) were evaluated. The simulation results showed that contrast values for DEW, TEW, and new approach were (0.45 ± 0.07, 0.5 ± 0.08, and 0.63 ± 0.09), SNR values (4.74 ± 0.94, 5.58 ± 1.08, and 6.56 ± 1.24), and RNB values (0.33 ± 0.06, 0.33 ± 0.07, and 0.33 ± 0.05), respectively. In clinical study, the contrast values for DEW, TEW, and new approach were 0.53 ± 0.03, 0.57 ± 0.07, and 0.62 ± 0.04 in rest MPI and were 0.52 ± 0.04, 0.57 ± 0.06, and 0.6 ± 0.05 in stress MPI, respectively. Moreover, for the rest images, the SNR values were 7.65 ± 1.9, 9.08 ± 2.2, and 10.2 ± 1.75 and for stress images were 7.76 ± 1.99, 9.12 ± 2.25, and 10.17 ± 2.04, respectively. Finally, RNB values for rest and stress images were 0.12 ± 0.03, 0.13 ± 0.03, and 0.13 ± 0.03, respectively. The simulation and the clinical studies showed that the new approach could be better performance than DEW, TEW methods, according to values of the contrast, and the SNR for scatter correction.

The Feasibility of Quantitative Assessment of Myocardial Perfusion Using Single Photon Emission Computed Tomography Imaging

The Feasibility of Quantitative Assessment of Myocardial Perfusion Using Single Photon Emission Computed Tomography Imaging