Technetium-99m-methylene diphosphonate single photon emission computed tomography/computed tomography combined with prostate-specific antigen/free prostate-specific antigen ratio for bone metastasis of prostate cancer

BACKGROUND Prostate cancer(PC)is one of the most common malignant tumors in men,and bone metastasis is one of its common complications,which seriously affects the quality of life and prognosis of patients.AIM To investigate the diagnostic value of technetium-99m-methylene diphosphonate(99mTc-MDP)single photon emission computed tomography(SPECT)/CT imaging combined with the serum prostate-specific antigen(PSA)/free PSA ratio for PC bone metastasis(PCBM).METHODS One hundred patients with PC who visited the Hospital of Chengdu University of Traditional Chinese Medicine from January 2020 to January 2022 were recruited as the experimental(Exp)group,while 30 patients with benign prostatic lesions(BPLs)were recruited as the control(Ctrl)group.All patients underwent 99mTc-MDP SPECT/CT imaging and serum PSA/fPSA testing.The SPECT/CT imaging results and serum PSA/fPSA ratios of patients were analyzed to evaluate their diagnostic values for PCBM.RESULTS The difference in general information of the patients was not obvious,showing comparability.The two methods showed no visible differences in negative predictive value and sensitivity for patients with PCBM,but had great differences in positive predictive value and specificity(P<0.05).The PSA/fPSA ratio of patients with PC in the Exp group was lower than those with BPLs,and patients with PCBM had a much lower PSA/fPSA ratio than those without PC(P<0.05).The results confirmed that the combined use of 99mTc-MDP SPECT/CT imaging and serum PSA/fPSA ratio achieved a detection rate of 95%for PCBM.CONCLUSION The combination of 99mTc-MDP SPECT/CT and PSA/fPSA ratio is accurate and reliable for the diagnosis of PCBM,which provides an important reference for clinical practice.

Pancreatic neuroendocrine tumor detected by technetium-99m methoxy-2-isobutylisonitrile single photon emission computed tomography/computed tomography:A case report

BACKGROUND Pancreatic neuroendocrine tumors(NETs)account for about 1%–2%of pancreatic tumors and about 8%of all NETs.Computed tomography(CT),magnetic resonance imaging,and endoscopic ultrasound are common imaging modalities for the diagnosis of pancreatic NETs.Furthermore,somatostatin receptor imaging is of great value for diagnosing pancreatic NETs.Herein,we report the efficacy of technetium-99m methoxy-2-isobutylisonitrile(99mTc-MIBI)single photon emission CT(SPECT)/CT for detecting pancreatic NETs.CASE SUMMARY A 57-year-old woman presented to our hospital with a 1-d history of persistent upper abdominal distending pain.The distending pain in the upper abdomen was aggravated after eating,with nausea and retching.Routine blood test results showed a high neutrophil percentage,low leukomonocyte and monocyte percentages,and low leukomonocyte and eosinophil counts.Amylase,liver and kidney function,and tumor markers alpha-fetoprotein,carcinoembryonic antigen,and cancer antigen(CA)125,CA72-4,CA19-9,and CA153 were normal.Abdominal CT showed a mass,with multiple calcifications between the pancreas and the spleen.The boundary between the mass and the pancreas and spleen was poorly defined.Contrast-enhanced CT revealed that the upper abdominal mass was unevenly and gradually enhanced.99mTc-MIBI SPECT/CT revealed that a focal radioactive concentration,with mild radioactive concentration extending into the upper abdominal mass,was present at the pancreatic body and tail.The 99mTc-MIBI SPECT/CT manifestations were consistent with the final pathological diagnosis of pancreatic NET.CONCLUSION 99mTc-MIBI SPECT/CT appears to be a valuable tool for detecting pancreatic NETs.

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

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

Deep brain stimulation of the subthalamic nucleus treats Parkinson's disease through enhancing metabolic activity of the corpus striatum Verification by single photon emission computed tomography and positron emission tomography

BACKGROUND： Subthalamic nucleus deep brain stimulation （STN DBS） for Parkinson＇s disease （PD） has achieved good effects, but to date the mechanism of STN DBS remains poorly understood STN DBS may increase dopamine levels or metabolic activity of the corpus striatum. OBJECTIVE： To validate the effects of STN DBS on dopamine metabolism and glucose metabolism in the corpus striatum of hemiparkinsonian monkeys using single photon emission computed tomography （SPECT） and position emission tomography （PET）. DESIGN, TIME AND SET＇rING： A controlled animal study was performed at the Neurosurgery Laboratory, Changhai Hospital of the Second Military Medical University of Chinese PLA between January 2004 and December 2007. METHODS： Hemiparkinsonism was induced in adult Rhesus Macaque monkeys, which exhibit similar characteristics of PD in humans, through unilateral internal carotid artery infusion of 1-methy-4-phenyl-1, 2, 3, 6-tetrahydropyrindine. Following model establishment, stimulation electrodes were implanted in the right STN, and chronic high-frequency stimulation （60 μs pulse width, 130 Hz frequency, and 1.5-2.0 V pressure） was performed. MAIN OUTCOME MEASURES： The changes in dopamine transporter （DAT）, D2 receptor （D2R）, and glucose metabolism in the corpus striatum following STN DBS were observed using SPECT and PET. RESULTS： SPECT examination showed that DAT specific binding in the right corpus striatum was increased at 3 months after DBS compared with prior to stimulation, and D2R specific binding in the right corpus striatum gradually decreased near levels on the left （non-electrode-implanted） side within 3 months after DBS. PET examination showed that the glucose metabolism in the right corpus striatum was markedly increased at 3 months after effective DBS. Hemiparkinsonism monkeys showed improved left limb rigidity, increased activities, and stable gait under chronic high-frequency stimulation. CONCLUSION： STN DBS increased striatal DAT, decreased D2R, and enhanced glucose metabolism, suggesting that chronic, high-frequency STN stimulation enhanced the metabolic activity of the corpus striatum, a mechanism for improving the PD symptoms of hemiparkinsonian monkeys.

Quantification of Tc-99m-ethyl cysteinate dimer brain single photon emission computed tomography images using statistical probabilistic brain atlas in depressive end-stage renal disease patients:Correlation with disease severity and symptom factors

This study adapted a statistical probabilistic anatomical map of the brain for single photon emission computed tomography images of depressive end-stage renal disease patients. This research aimed to investigate the relationship between symptom clusters, disease severity, and cerebral blood flow. Twenty-seven patients （16 males, 11 females） with stages 4 and 5 end-stage renal disease were enrolled, along with 25 healthy controls. All patients underwent depressive mood assessment and brain single photon emission computed tomography. The statistical probabilistic anatomical map images were used to calculate the brain single photon emission computed tomography counts. Asymmetric index was acquired and Pearson correlation analysis was performed to analyze the correlation between symptom factors, severity, and regional cerebral blood flow. The depression factors of the Hamilton Depression Rating Scale showed a negative correlation with cerebral blood flow in the left amygdale. The insomnia factor showed negative correlations with cerebral blood flow in the left amygdala, right superior frontal gyrus, right middle frontal gyrus, and left middle frontal gyrus. The anxiety factor showed a positive correlation with cerebral glucose metabolism in the cerebellar vermis and a negative correlation with cerebral glucose metabolism in the left globus pailidus, right inferior frontal gyrus, both temporal poles, and left parahippocampus. The overall depression severity （total scores of Hamilton Depression Rating Scale） was negatively correlated with the statistical probabilistic anatomical map results in the left amygdala and right inferior frontal gyrus. In conclusion, our results demonstrated that the disease severity and extent of cerebral blood flow quantified by a probabilistic brain atlas was related to various brain areas in terms of the overall severity and symptom factors in end-stage renal disease patients.

Same day yttrium-90 radioembolization with single photon emission computed tomography/computed tomography: An opportunity to improve care during the COVID-19 pandemic and beyond

BACKGROUND The coronavirus disease 2019(COVID-19)pandemic has made it more challenging for patients to undergo yttrium-90(Y-90)radioembolization(RE).Same day Y-90 RE provides an opportunity to minimize logistical challenges and infection risk associated with COVID-19,thus improving patient access.AIM To describe the use of same day Y-90 RE with routine single photon emission computed tomography/computed tomography(SPECT/CT)in order to optimize therapy.METHODS All patients were selected for Y-90 RE through a multidisciplinary tumor board,and were screened and tested for COVID-19 infection per institutional protocol.A same day procedure was developed,consisting of angiography,imaging,and Y-90 resin particle delivery.Routine SPECT/CT after technetium-99m macroaggregated albumin(Tc-99m MAA)administration was performed for assessment of arterial supply,personalized dosimetry,and extrahepatic activity.Post-treatment Y-90 bremsstrahlung SPECT/CT was performed for confirmation of particle delivery,by utilization of energy windowing to limit signal from previously administered Tc-99m MAA particles.RESULTS A total of 14 patients underwent same day Y-90 RE between March and June 2020.Mean lung shunt fraction was 6.13%(range 3.5%-13.1%).Y-90 RE was performed for a single lesion in 7 patients,while the remaining 7 patients had treatment of multifocal lesions.The largest lesion measured 8.3 cm.All patients tolerated the procedure well and were discharged the same day.CONCLUSION Same day Y-90 RE with resin-based microspheres is feasible,and provides an opportunity to mitigate infection risk and logistical challenges associated with the COVID-19 pandemic and beyond.We recommend consideration of SPECT/CT,especially among patients with complex malignancies,for the potential to improve outcomes and eligibility of patients to undergo same day Y-90 RE.

Three-dimensional stereotactic surface projection in the statistical analysis of single photon emission computed tomography data for distinguishing between Alzheimer's disease and depression

AIM To evaluate usefulness of single photon emission computed tomography(SPECT) with three-dimensional stereotactic surface projection(3D-SSP) in distinguishing between Alzheimer's disease(AD) and depression.METHODS We studied 43 patients who presented with both depressive symptoms and memory disturbance. Each subject was evaluated using the following:(1) the Minimal Mental State Examination;(2) the Hamilton Rating Scale for Depression;(3) Clinical Global Impression-Severity scale(CGI-S); and(4) SPECT imaging with 3D-SSP.RESULTS The MMSE scores correlated significantly with the maximum Z-scores of AD-associated regions. CGI-S scores correlated significantly with the maximum Z-scores of depression-associated regions. Factor analysis identified three significant factors. Of these, Factor 1 could be interpreted as favouring a tendency for AD, Factor 2 as favouring a tendency for pseudo-dementia, and Factor 3 as favouring a depressive tendency.CONCLUSION We investigated whether these patients could be categorized as types: Type A(true AD), Type B(pseudodementia), Type C(occult AD), and Type D(true depression). The factor scores in factor analysis supported the validity of this classification. Our results suggest that SPECT with 3D-SSP is highly useful for distinguishing between depression and depressed mood in the early stage of AD.

Cerebral functional imaging of Waiguan (SJ 5) acupoint specificity using single-photon emission computed tomography

The action of needling in acupoint therapy has to first be regulated and integrated by the brain, and then it affects the target organ and manifests its therapeutic effects, which is dependent on the specificity of the acupoints. The authors put forward the hypothesis of the ＂acupoint-related brain＂. Single-photon emission computed tomography was used to explore the activation of brain regions following true needling in true acupoint Waiguan （SJ 5）, sham needling in true acupoint Waiguan, true needling in a sham point, and sham needling in a sham point. The relative specificity of Waiguan in normal persons was analyzed by observing changes in regional cerebral blood flow. Compared with the sham needling in true acupoint group and sham needling in the sham point group, acupuncture at Waiguan can activate brain regions controlling movement. Compared with true needling in the sham point group, acupuncture at Waiguan can also activate brain regions controlling movement. The results suggest that the specificity of needling at an acupoint is related to certain activated cerebral functional regions, which are associated with the clinical application of the acupoint.

Rest Thallium-201/Stress Technetium-99m Sestamibi Dual-Isotope Myocardial Perfusion Single-Photon Emission Computed Tomography in Detecting of Chronic Coronary Artery Disease

To investigate diagnostic accuracy of 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT in chronic coronary artery disease. Sixty-seven patients with suspected CAD were enrolled in the prospective study. All patients underwent myocardial perfusion scintigraphy in SPECT with dual isotopes of T1-201 and dipyridamole stress Tc-99m sestamibi. Rest and stress imaging protocol were performed in 2 hours by dose of 3 mCi TI-201 and 25 mCi Tc-99m sestamibi. The acquisition parameters includes LEHR collimator, energy peak of 72 and 167 keV for T1-201 and 140 keV for Tc-99m, 180-degree rotation from RAO to LPO, matrix size 64x64, and 25second/frame/64 frames. The 20-segment model of left ventricle was used in automatic quantitation software. Coronary angiography was used as gold standard. CAD was defined as 50% of lumen stenosis on coronary angiography. Rest TI-201/stress tc-99m sestamibi dual-isotope SPECT demonstrated a sensitivity of 94.59% and specificity of 70%, positive predictive value of 79.54% and negative predictive value of 91.3% in detection of coronary artery disease. Sensitivity and specificity for detecting multi-vessel coronary artery disease were 82.75% and 81.57% for the left anterior descending, 77.77% and 91.83% for left circumflex and 94.11% and 82% for right coronary artery. 2-hour protocol of rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT has high sensitivity, specificity, positive predictive value and negative predictive value in detecting chronic coronary artery disease with greater than 50% stenosis assessed by coronary angiography Moreover, this imaging protocol gives high imaging quality, time-saving and convenience.

Dopamine transporter distribution in patients with Parkinson disease of different stages detected using single-photon emission computed tomography brain imaging

BACKGROUND： Literatures have reported that the density changes of dopamine transporter is negatively correlated with the severity degree and grading of disease condition of Parkinson disease （PD）. However, the distribution ofdopamine transporter in each nucleus of corpora striatum at each period is still unclear. OBJECTIVE： To observe the radioactive uptake distribution of dopamine transporter in bilateral corpora striata of patients with different stages of PD using single photon emission computed tomography （SPECT）, and make a comparison with healthy controls. DESIGN： Case-control analysis. SETTING： Department of Imageology, Second Hospital Affiliated to Guangzhou University of Chinese Medicine. PARTICIPANTS： Thirty patients with PD admitted to Second Hospital Affiliated to Guangzhou University of Traditional Chinese Medicine between January and December 2005 were recruited. The involved patients, 19 male and 11 female, were aged from 36 to 80 years and with disease course of 2.5 months to 10 years. They all met the clinical diagnosis criteria of Britain Parkinson＇s disease Association Think Tank; Following Hoehn-Yahr grading： grade Ⅰ ： unilateral morbidity; grade Ⅱ： bilateral morbidity, but without balance disorder; grade Ⅲ： bilateral morbidity, accompanied with early posture balance disorder; grade Ⅳ： severe morbidity, needs more help; grade V ： without help, only in bed or wheelchair. There were 11 patients with mild PD （grade Ⅰ - Ⅱ ）, 9 patients with moderate PD （grade Ⅲ） and 10 patients with advanced PD （grade Ⅳ - Ⅴ ）. Meanwhile, 6 healthy persons were selected as normal controls. Informed consents were obtained from all the subjects. METHODS： Twenty-four hours after withdrawal of PD drugs, 30 patients with PD and 6 healthy controls took kalium perchloricum 400 mg orally. After lying down for 30 minutes, all the subjects were intravenously injected with 740 MBq 99Tc m-TRODAT-1 （Jiangsu Institute of Atomic Medicine, Batch No. 20040310） at elbow part. Following injection, image was collected using scanner for single photon emission computed tomography （ADAC Company, USA）. Matrix was 64 × 64, each detecting head revolved 180 ° , 1 frame/60 s. Sixty-four frames were collected with double detecting heads, 50 K/frame. Faultages with clearest image of corpora striatum were selected. Regions of interest （ROI） of caudate nucleus, anterior and posterior putamen and thalamic region in bilateral corpora striata were radioactively counted, and mean value of radioactive counting of ROI was used as the mean value ofpixel in each region of bilateral corpora striata. MAIN OUTCOME MEASURES： Comparison of radioactive uptake in each region of brain between healthy persons and patients with PD. RESULTS： Thirty patients with PD and six healthy persons who received body examination participated in the final result. Comparison of radioactive uptake in each region between healthy persons and patients with PD： ①In the healthy persons, high-density radioactive uptake was found in bilateral corpora striata; Structures of caudate nucleus, anterior and posterior putamen, and thalamus were clear with eudipleural radioactive distribution, and the background of peripheral brain tissue was very low. ②Radioactive intakes in opposite anterior and posterior putamen of patients with mild PD were significantly inferior to those in homolateral ones（70.45±3.35, 87.64±2.65, t =15.82, P 〈 0.05）. Structures of bilateral caudate nucleus and thalamus were clear with eudipleural radioactive distribution （P 〉 0.05）. ③Radioactive intakes in anterior and posterior putamen and thalamus of patients with moderate PD were significantly reduced as compared with healthy persons. There were significant differences in mean radioactive counting of ROI between patients with PD and healthy persons （t =5.20, P 〈 0.05： t =3.95, P 〈 0.05）; The structure of opposite caudate nucleus was not very clear, radioactive distribution of opposite caudate nucleus was significantly reduced as compared with homolateral one （81.11±4.25, 104.56±3.64, t = 14.65, P 〈 0.05）. ④As for patients with advanced PD, the structure of bilateral corpora striata was not clear, radioactive intake was significantly reduced and peripheral background was heightened, even higher than the distribution of the whole corpora striatum. CONCLUSION： SPECT DAT imaging of brain can show the distribution of radioactive uptake in each region of bilateral corpora striata of patients with different stages of PD, which is helpful to diagnose and evaluate the severity of PD.

Diffusion-weighted magnetic resonance imaging with short T1 inversion recovery-echo planar imaging combined with dual-head coincidence single photon emission computed tomography for diagnosing solitary pulmonary nodule

Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.

Correlations of single photon emission computed tomography joints scan and bone metabolic markers in active rheumatoid arthritis

Objective To explore the correlation between quantitative value of joint bone scan by single photon emission computed tomography(SPECT)and serum bone metabolic markers in patients with active rheumatoid arthritis(RA).Methods Clinical data of 60 newly diagnosed RA patients were retrospectively collected in Department

Evaluating the Effectiveness of Electro-Acupuncture as A Treatment for Childhood Autism Using Single Photon Emission Computed Tomography

Objective：To explore the effectiveness of electro-acupuncture（EA）in the treatment of childhood autism（CA）and evaluate its effectiveness using single photon emission computed tomography（SPECT）.Methods：A total of 55 CA patients（4.52±2.73 years）were enrolled in this study.All patients received EA treatments and were examined by SPECT before and after treatments.Results：Following treatment,the intracerebral multiple focal radioactivity distribution defect areas of CA patients were observed to be partially filled.Specifically,significant differences in the ratios of regional cerebral blood flow and global cerebral blood flow before（Fb）and after（Fe）EA treatment in different lesions were observed（in the left prefrontal cortex,t=5.01,P〈0.01;in the right prefrontal cortex,t=2.32,P〈0.05;in the left temporal lobe,t=4.54,P〈0.01;in the right temporal lobe,t=2.90,P〈0.05;in the left Broca’s area,t=5.82,P〈0.01）.After EA treatment,the patients exhibited symptomatic relief.Conclusion：EA is useful to treat CA and SPECT can be used to evaluate the effectiveness of this treatment.

Positron emission computed tomography/single photon emission computed tomography in Parkinson disease

Parkinson disease(PD)is the second-most common neurodegenerative disorder.Its main pathological mechanism is the selective degeneration and deletion of dopaminergic neurons in the dense part of the substantia nigra and the damage of dopaminergic neurons caused by the abnormal deposition of a Lewy body,leading to a decreased dopamine level.Positron emission computed tomography(PET)/single photon emission computed tomography(SPECT)is a molecular imaging technology that can directly or indirectly reflect changes in molecular levels by using a specific tracer.With the research and development on the tracers of related enzymes for labeling dopamine transporter and dopamine receptor and for being involved in dopamine formation,this imaging technology has been applied to all aspects of PD research.It not only contributes to clinical work but also provides an important theoretical basis for exploring the pathological mechanism of PD at a molecular level.Therefore,this review discusses the application value of PET/SPECT in PD in terms of early diagnosis,disease severity evaluation,clinical manifestations,differential diagnosis,and pathological mechanism.

Perioperative Evaluation of Cerebral Blood Flow Using ^123I-labeled N-isopropyl-p-iodoamphetamine Single-Photon Emission Computed Tomography without Blood Sampling in Patients Who Underwent Carotid Artery Stenting

The evaluation of regional cerebral vascular reserve （rCVR） with single-photon emission computed tomography （SPECT） is useful for predicting cerebral hyperperfusion following carotid artery stenting （CAS） and carotidendarterectomy （CEA）.

Reversible posterior leukoencephalopathy syndrome: single photon emission computerized tomography observations

The authors report clinical correlations of single photon emission computerized tomography (SPECT) findings in reversible posterior leukoencephalopathy (RPL). These are observations that have not received wide attention in literature. A 31-year-old hypertensive gentleman, on discontinuing antihypertensive medications, presented with vomiting, headache, focal motor to bilateral tonic-clonic seizures, altered sensorium, right gaze palsy and right hemiparesis. Accelerated hypertension was noted and he improved well with antihypertensive and anticonvulsant therapy. While cranial magnetic resonance imaging (MRI) revealed extensive bilateral lesions, SPECT imaging revealed perfusion defects involving bilateral basal ganglia, left parieto-occipital, right cerebellar and right occipital regions, which corresponded with clinical deficits on examination. While MRI is the standard of care for the evaluation of RPL, this case suggests that SPECT abnormalities may be better localized to the pathogenic lesions. Furthermore, this may begin to explain the pathophysiology of injury in RPL.

PET image reconstruction with a system matrix containing point spread function derived from single photon incidence response

A point spread function（PSF） for the blurring component in positron emission tomography（PET） is studied. The PSF matrix is derived from the single photon incidence response function. A statistical iterative reconstruction（IR） method based on the system matrix containing the PSF is developed. More specifically, the gamma photon incidence upon a crystal array is simulated by Monte Carlo（MC） simulation, and then the single photon incidence response functions are calculated. Subsequently, the single photon incidence response functions are used to compute the coincidence blurring factor according to the physical process of PET coincidence detection. Through weighting the ordinary system matrix response by the coincidence blurring factors, the IR system matrix containing the PSF is finally established. By using this system matrix, the image is reconstructed by an ordered subset expectation maximization（OSEM） algorithm. The experimental results show that the proposed system matrix can substantially improve the image radial resolution, contrast,and noise property. Furthermore, the simulated single gamma-ray incidence response function depends only on the crystal configuration, so the method could be extended to any PET scanner with the same detector crystal configuration.

Single photon emission computer tomography of dopamine transporters in monkeys and humans with ^(99m)Tc-TRODAT-1

Background The diagnosis of Parkinson’s disease is presently based on non-specific symptoms. However, radionuclide dopamine transporters imaging can provide specific diagnostic tool for Parkinson’s disease. This study was designed to investigate the effects of imaging of dopamine transporters with 99mTc-TRODAT-1 in early diagnosis or differential diagnosis of Parkinson’s disease.Methods Nine normal monkeys were used to establish N-methyl-4-phenyl-1, 2, 3, 6-tetra-hydropyridine (MPTP) hemi-Parkinsonian animal models, and they were subjected to imaging. Twenty-nine patients with Parkinson’s disease, 12 age-matched healthy volunteers, and 18 age-matched patients with Parkinson’s syndrome were investigated. Single photon emission computer tomography (SPECT) was performed 3 hours after intravenous injection of 740 MBq 99mTc-TRODAT-1. Striatum specific uptake of 99mTc-TRODAT-1 was calculated according to the ratio of striatum (ST) to cerebellum (CB)in dopamine transporters uptake.Results In normal monkeys, bilateral ratio of ST/CB was 2.34±0.41. After the injection of MPTP, uptake rate of 99mTc-TRODAT-1 at damaged region was much lower than that at the contralateral region, resulting in a significant difference in the ratio of ST/CB (right: ST/CB=1.73±0.35; left: ST/CB=1.90±0.30), especially in hemi-Parkinsonian model monkeys (right: ST/CB=1.29±0.17; left: ST/CB=1.80±0.33). The ratios of ST/CB were 1.57±0.17 and 1.61±0.14 for the right and left respectively in the healthy volunteers, 1.04±0.29 and 1.06±0.30 in the age-matched patients with Parkinson’s disease, and 1.56±0.17 and 1.59±0.18 in the age-matched patients with Parkinson’s disease syndrome. A significant difference was noted between group of Parkinson’s disease, normal controls and Parkinson’s disease syndrome. Conclusion The results suggest that 99mTc-TRODAT-1 dopamine transporters SPECT has clinical application value in early diagnosis or differential diagnosis of Parkinson’s disease.

R-I subtype single right coronary artery with congenital absence of left coronary system: A case report

BACKGROUND Isolated single coronary artery is a rare congenital anomaly.R-I subtype single coronary artery is even rarer.In this subtype,a very large right coronary artery extends in the coronary sulcus to the anterior base of the heart where it produces the left anterior descending coronary artery.Currently,only a few case reports are available in the literature for this anomaly.CASE SUMMARY Here,we report the case of a 62-year-old woman who presented to the cardiology clinic with decreased exercise tolerance and poor blood pressure control.The patient underwent coronary angiography(CAG)and emission computed tomography(ECT).CAG images revealed a single gigantic right coronary artery(R-I type)arising from the right coronary sinus with branches supplying the left coronary territory.The ECT results confirmed myocardial ischemia at the location of the absent left coronary artery.The ECT findings confirmed that ischemia was consistent with the vascular loss location in CAG images.In such anomalies,there is a compensatory widening of the coronary artery lumen.Medical treatment was administered,and the patient was discharged.CONCLUSION Isolated single coronary arteries are associated with ischemia and potentially fatal acute coronary events.Hence,controlling risk factors is critical.

Incidence of exclusive extrapelvic skeletal metastasis in prostate carcinoma on bone scintigraphy

BACKGROUND Bone is one of the common sites of metastasis from prostate carcinoma.Bone scintigraphy(BS)is one of the most sensitive imaging modalities currently used for bone metastatic work-up.Skeletal metastasis in prostate carcinoma commonly involves pelvic bones but rarely involves extrapelvic-extraspinal sites.AIM To retrospectively analyze the BS data to determine the pattern of skeletal metastases in the prostate carcinoma.METHODS This retrospective observational study involves patients with biopsy-proven prostate carcinoma referred for BS for staging assessment.Patients with abnormal BS were evaluated for the pattern of skeletal involvement and data were pre-sented in descriptive format in the form of percentages.RESULTS A total of 150 patients with biopsy-proven prostate cancer who were referred for staging were included in the study.Thirteen of 150 patients(8.67%)had no abnormal uptake on planar images,ruling out metastatic disease.Twenty-four patients(16%)had heterogeneous uptake in the spine with distribution charac-teristic of degenerative disease and no scan pattern of metastatic disease.Thirty patients(20%)had multifocal uptake involving both pelvic and extra pelvic bones on planar images typical for skeletal metastasis and were considered metastatic.Eighty-three out of 150 patients(55.3%)had increased tracer uptake,which was indeterminate,thus,single photon emission computed tomography-computed tomography(SPECT-CT)was acquired,which showed 51 with metastatic disease,31 benign lesions,and one indeterminate finding.Seven of 150 patients had exclusive pelvic bone uptake,which was found to be metastatic in 4/7 patients in SPECT-CT.Fifty six out of 150 patients showed exclusive extrapelvic tracer uptake,of which only 3 had vertebral metastatic disease.None of the patients with increased uptake exclusively in the extrapelvic-extraspinal location was metastatic.CONCLUSION The incidence of exclusive extrapelvic skeletal metastatic disease in prostate carcinoma is 2%(excluding one patient with indeterminate findings).Further,none of the patients in the current study had exclusive extrapelvic-extraspinal metastasis.Thus,exclusive extrapelvic-extraspinal focal abnormality on planar BS carries a very low probability of metastatic disease and hence,further imaging or SPECT-CT can be safely avoided in such cases.