• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.201-208
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• 2007

Purpose: We investigated whether the diagnostic performance of SPECT scintimammography (SMM) can be improved by adding computer-aided diagnosis (CAD) of ultrasonography (US). Materials and methods: We reviewed breast SPECT SMM images and corresponding US images from 40 patients with breast masses (21 malignant and 19 benign tumors). The quantitative data of SPECT SMM were obtained as the uptake ratio of lesion to contralateral normal breast. The morphologic features of the breast lesions on US were extracted and quantitated using the automated CAD software program. The diagnostic performance of SPECT SMM and CAD of US alone was determined using receiver operating characteristic (ROC) curve analysis. The best discriminating parameter (D-value) combining SPECT SMM and the CAD of US was created. The sensitivity, specificity and accuracy of combined two diagnostic modalities were compared to those of a single one. Results: Both SPECT SMM and CAD of US showed a relatively good diagnostic performance (area under curve = 0.846 and 0.831, respectively). Combining the results of SPECT SMM and CAD of US resulted in improved diagnostic performance (area under curve =0.860), but there was no statistical differerence in sensitivity, specificity and accuracy between the combined method and a single modality. Conclusion: It seems that combining the results of SPECT SMM and CAD of breast US do not significantly improve the diagnostic performance for diagnosis of breast cancer, compared with that of SPECT SMM alone. However, SPECT SMM and CAD of US may complement each other in differential diagnosis of breast cancer.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.353-360
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• 2012

Diverse designs of collimator have been applied to Single Photon Emission Computed Tomography (SPECT) according to the purpose of acquisition; thus, it is necessary to reflect geometric characteristic of each collimator for successive image reconstruction. This study carry out reconstruction algorithm for imaging system in nuclear medicine with pinhole collimator. Especially, we study to solve sampling problem which caused in the system model of pinhole collimator. System model for a maximum likelihood expectation maximization (MLEM) was developed based on the geometry of the collimator. The projector and back-projector were separately implemented based on the ray-driven and voxel-driven methods, respectively, to overcome sparse sampling problem. We perform phantom study for pinhole collimator by using geant4 application for tomographic emission(GATE) simulation tool. The reconstructed images show promising results. Designed iterative reconstruction algorithm with unmatched system model effective to remove sampling problem artefact. Proposed algorithm can be used not only for pinhole collimator but also for various collimator system of imaging system in nuclear medicine.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.2
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• pp.112-119
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• 2009

Purpose: This study was performed to investigate the clinical significance of reverse redistribution(RR) phenomenon detected on delayed Tc-99m tetrofosmin myocardial single photon emission computed tomography(SPEG) in patients with acute myocardial infarction after revascularization. Materials and Methods: A Tc-99m tetrofrosmin myocardial SPECT was performed in 67 consecutive patients after revascularization for acute myocardial infarction. Myocardial SPECT imaging was performed for early imaging at 40 min and for delayed imaging at 180 min after reinjection at myocardial stress. Regional myocardial uptakes were scored by 4-point scoring in the left ventricular wall divided into 17 segments. Reverse redistribution was defined as an increase of more than 2 point in the activity score on the delayed image. Follow-up myocardial SPECT and coronary angiography(CAG) were performed 9 months later. Results: On myocardial SPECT performed following revascularization, RR was observed in 100 of all 319 segments(31%) and in 43 patients(64%). The abnormalities of perfusion and regional wall motion were more severe in the patients with RR compared to those without RR(p<0.05). On follow-up myocardial SPECT, the myocardial perfusion, regional wall motion, and myocardial thickness were significantly improved in the patients with RR(p<0.05) however, these changes were not significant in those without RR. There was no significant difference between the patients with RR and those without RR in the occurrence of restenosis on CAG. Conclusions: In patients with acute myocardial infarction, the regions showing the RR phenomenon on delayed Tc-99m tetrofosmin SPECT may reflect viable myocardium and indicate recovery of salvaged myocardium.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.219-231
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• 2016

$^{99m}Tc$-DMSA planar scan that can analyze the functions of kidney quantitatively provides less information on a lesion than tomography scanning. Therefore, this study applied a high sensitivity all-purpose collimator that is sensitive to photonic signals to $^{99m}Tc$-DMSA and carried out a clinical scan with single photon emission computed tomography (SPECT). And diagnostic accuracy and time requirement of were analyzed to know the clinical usefulness of the applied scanning method. 10 subjects were intravenously injected with radiopharmaceutical product (1.0-1.2 MBq/kg) and scanned by a gamma camera with planar scanner (high resolution (HR)-mode, $256{\times}256$, 50 kcts/view, 4 image) and SPECT (HR / high sensitive (HS)-mode, $128{\times}128$, step and shoot, $180^{\circ}$, variable sec/angle, total 64 frame, OSEM reconstruction), respectively. The collected data was compared with an analysis program. The results showed that HS-mode SPECT detected total counts 1.8-5.6 times more than planar scan. Relative renal function evaluated based on the counts was not significantly different by two scanning methods (p=0.96) and it turned out that test time was shortened by 39% when HS-mode SPECT was used. Therefore, SPECT using HR, HS-mode collimator could analyze renal function more quantitatively than using planar scan and the former could diagnose the location information of a lesion more accurately than the latter as well as shortened test time requirement, which demonstrated the clinical usefulness of $^{99m}Tc$-DMSA renal SPECT using high sensitivity all purpose collimator.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.22-30
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• 1995

To predict preoperatively the safety of permanent occlusion of an internal carotid artery with $^{99m}Tc$-HMPAO brain single photon emission computed tomography(SPECT) from an objective point of view, Twenty-four patients underwent balloon test occlusion (BTO) of the internal carotid arteries because of neck and skull base tumors. The authors assessed the uptake of both middle cerebral artery territories before and during BTO with $^{99m}Tc$-HMPAO brain SPECT using semiquantitative analysis method and compared the results with other factors(neurologic examination, arterial stump pressure and electroenceph-alogram). Nineteen patients had not experienced neurological deteriorating or any problem during BTO. Their comparative uptakes of the middle cerebral artery territories were 95 to 101% of the pre-BTO state. The remaining five patients showed severe neurologic symptoms such as transient hemiplegia and unconsciousness. Their comparative uptake of the middle cerebral artery territories were 77 to 85% of the pre-BTO state, and were well matched with other factors. $^{99m}Tc$-HMPAO brain SPECT before and during BTO seems to be a simple and objective method for prediction of permanent neurologic deficits when the comparative uptake of middle cerebral artery territories during BTO is lower than 85% of that before BTO.

• Progress in Medical Physics
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• v.10 no.2
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• pp.73-81
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• 1999

Scatter correction for single photon emission computed tomography (SPECT) plays an important role to improve image quality and quantitation. The purpose of this study was to investigate three scatter correction methods using Monte Carlo simulation. Point source and Jaszack phantom filled with Tc-99m were simulated by Monte Carlo code, SIMIND. For scatter correction, we applied three methods, Compton window (CW) method, triple window (TW) method, and dual photopeak window (DPW) method. Point sources located at various depths along the center line within a 20-cm phantom were simulated to calculate the window ratios and corresponding scatter fractions by evaluating the polynomial coefficients for DPW method. Energy windows were located in W$_1$=92-125 keV, W$_2$=124-126 keV, W$_3$=136-140 keV, W$_4$=140-141 keV, and W$_{5}$=154-156 keV. The results showed that in Jaszack phantom with cold sphere and hot sphere, the TW gave the closest contrast and percentage recovery to the ideal image, respectively, while CW overestimated and DPW underestimated the contrast of ideal one. All three scatter correction methods showed an improved image contrast. In conclusion, scatter correction is essential for improving image contrast and accurate quantification. The choice of scatter correction method should be made on the basis of accuracies and ease of implementation.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.2
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• pp.49-53
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• 2016

Purpose Recently, Cadmium-zinc-telluride (CZT) semiconductor myocardial SPECT (Single Photon Emission Computed Tomography) has been used myocardial scintigraphy. In this study, the performance of Semiconductor SPECT and conventional SPECT systems was compared by a comprehensive analysis of phantom SPECT images. Materials and Methods Methods: We evaluated the DSPECT CZT SEPCT (Spectrum-dynamic) and INFINA conventional (GE). Physical performance was compared on reconstructed SPECT images from a phantom. Results For count sensitivity on cardiac phantom images ($counts{\cdot}sec^{-1}{\cdot}MBq^{-1}$), DSPECT had a sensitivity of conventional SPECT. This classification was similar to that of myocardial counts normalized to injected activities from phantom images (respective mean values, $counts{\cdot}sec^{-1}{\cdot}MBq^{-1}$: 195.83 and 52.83). For central spatial resolution: DSPECT, 9.47mm; conventional SPECT, 16.90mm. For contrast-to-noise ratio on the phantom: DSPECT, 4.2; conventional SPECT, 3.6. Conclusion The performance of CZT cameras is dramatically higher than that of conventional SPECT. However, CZT cameras differ in that spatial resolution and contrast-to-noise ratio are better with conventional SPECT, whereas count sensitivity is markedly higher with the DSPECT.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.84-87
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• 2017

Cerebral hyperperfusion syndrome (CHS) is a rare complication that can occur when conducting stent insertion or endarterectomy in patients with carotid artery stenosis and is known to be caused by various mechanisms when the blood volume abruptly increases. The main clinical symptoms are unilateral headache, hypertension, seizure, and focal neurologic deficit. Subarachnoid hemorrhage and parenchymal hemorrhage may lead to permanent impairment or death in severe cases. CHS can be predicted by using transcranial Doppler, perfusion magnetic resonance imaging, and single photon emission computed tomography. In our case report, a patient developed CHS subsequent to significant venous congestion caused by carotid artery stent insertion. The patient had preexisting, symptomatic bilateral carotid artery stenosis. Venous congestion occurs when the direction of blood flow changes because of increased blood volume in patients with well-developed collateral vessels. We believe that CHS can be predicted from this finding. This study reports the possibility that CHS could be confirmed by cerebral angiography after insertion of the internal carotid stent.

• Journal of Sericultural and Entomological Science
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• v.46 no.2
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• pp.77-79
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• 2004

To investigate whether BF-7, extracted from Bombyx mori, improved learning and memory of ordinary people, K-WAIS (Korean version of Wechsler adult intelligence scale) was performed in 4 normal students. Treatment with 400 mg of BF-7 increased mean IQ from 103 to 114. To know how BF-7 plays such a positive role, we measured the blood flow to brain, especially for the area concerned with learning and memory, with Single Photon Emission Computed Tomography(SPECT). Our result showed that the blood flow to parahippocampal gyrus and medial temporal area was increased. Also, our results showed the image representing the increase of blood supply in this area. So, our results suggest that BF-7 effectively help to use brain concerning with learning and memory.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.20 no.3
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• pp.122-128
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• 2009

Objectives : Autism is a well-known psychiatric disorder that is presumed to have a neural basis. To investigate the underlying neurofunctional abnormalities of autism, the authors performed single photon emission computed tomography (SPECT) on children with autism. Methods : Fifty-five children with untreated autism (47 boys and 8 girls, mean age=$50.6{\pm}20.28$ months) were selected from among the patients visiting the child and adolescent psychiatric clinic of Seoul National University Hospital. Psychiatrists had diagnosed the participants according to the DSM-IV criteria for autistic disorder and the Childhood Autism Rating Scale (CARS) criteria for a diagnosis of autism. All participants were examined using 99mTC-HMPAO Brain SPECT. Using statistical parametric mapping (SPM) analysis, we compared the participants' SPECT images to standardized SPECT images of normal children, which had been retrospectively selected by the authors, on a voxel by voxel basis. Voxels with a p-value less than .001 were considered to be significantly different. Results : The autistic group showed significant hypoperfusion in the right medial frontal gyrus, right precentral gyrus, and left precuneus gyrus. In addition, they showed no significant hyperperfusion areas when compared to the control group. Conclusion : The findings of hypoperfusion in the medial-frontal lobe and precuneus are accord with hemodynamic abnormalities that have been already reported. Therefore, these findings are compatible with the recently suggested "theory of mind" hypothesis and the disturbances in attention shifting that have been observed in autistic children.