• The Korean Journal of Nuclear Medicine
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• v.25 no.1
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• pp.37-45
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• 1991

Infarct size is a major determinant of prognosis after acute myocardial infarction. Up to date, however, clinically available tests to estimate this size have not been sufficiently accurate. Twelve lead electrocardiogram and wall motion abnormality measurement are not quantitative, and creatine phophokinase (CPK) measurement is inaccurate in the presence of reperfusion or right ventricular infarction. Methods have been developed to localize and size acute myocardial infarcts with agents that are selectively sequestered in areas of myocardial damage, but previously used agents have lacked sufficient specificity. Antibodies that bind specifically only to damaged myocardial cells may resolve this problem and provide an accurate method for noninvasively measuring infarct size. We determined the accuracy with which infarcted myocardial mass can be measured using single photon emission computed tomography (SPECT) and radiolabeled antimyosin antibodies. Seven patients with acute myocardial infarction and one stable angina patient were injected with 2 mCi of Indium-111 labeled antimyosin antibodies. Planar image and SPECT was performed 24 hours later. None of the patients had history of prior infarcts, and none had undergone reperfusion techniques prior to the study, which was done within 4 days of the attack. Planar image showed all infarct patients to have postive uptakes in the cardiac region. The location of this uptake correlated to the infarct site as indicated by electrocardiography in most of the cases. The angina patient, however, showed no such abnormal uptake. Infarct size was determined from transverse slices of the SPECT image using a 45% threshold value obtained from a phantom study. Measured infarct size ranged from 40 to 192 gr. There was significant correlation between the infarct size measured by SPECT and that estimated from serial measurements of CPK (r=0.73, p<0.05). These date suggest that acute myocardial infarct size can be accurately measured from SPECT Indium-111 antimyosin imaging. This method may be especially valuable in situations where other methods are unreliable, such as early reperfusion technique, right ventricular infarct or presence of prior infarcts.

• The Korean Journal of Nuclear Medicine
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• v.23 no.2
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• pp.155-163
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• 1989

Regional cerebral perfusion was evaluated in 15 normal controls by single photon emission computed tomography using $^{99m}Tc$ HM-PAO. For quantitative analysis, 13 pairs of homologous region of interest (ROI) were drawn on three transverse slices matching the vascular territories and cerebral cortices, and normal values of 3 semiqunatitative indices including 'Right to left ratio'(R/L ratio), 'Regional index'(RI), and 'Region to cerebellum ratio'(R/cbll ratio) were calculated. Mean values of R/L ratios of homotogous regions were ranged from 0.985 to 1.023, and mean ${\pm}2$ s.d. of all regions did not exceed 11% of mean. Significant difference of RIs (mean count per voxel of a ROI/mean count per voxel of total ROIs) between regions were found (p<0.001) with highest values in occipital cortex and cerebellum. After attenuation correction, RIs in deep gray, cranial portion of anterior cerebral artery and vascular territories in the 2nd slice increased significantly (p < 0.05-0.001), but vise versa in other ROIs. Region to cerebellum ratios also showed regional difference similar to RIs.

• The Korean Journal of Nuclear Medicine
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• v.31 no.3
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• pp.310-319
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• 1997

This study investigated regional blood flow changes of frontal, temporal, and basal ganglia in eleven schizophrenic patients on DSM-IV criteria to examine the relationship between rCBF and clinical improvement of symptoms. Single-photon emission computed tomography imaging with $^{99m}Tc$-HMPAO was peformed in baseline and sixth weeks after the treatment, and concurrently psychopathology was assessed by PANSS. Antipsychotics wash-out period was more than 2 weeks, and three patient were drug naive. All patients were finally divided into two groups, the improved or not improved. We examined the difference of the amount of rCBF changes between two groups. Finally, frontal activity shows no significant difference between two groups but both groups show decreased frontal blood flow after antipsychotic treatment. However, the change of right temporal rCBF had positive correlation with the change of the total PANSS score, and the change of left temporal lobe activity was greater in the improved group than in the not improved group. Our results suggest that the temporal lobe activity has relation to the underlying schizophrenic symptoms.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.307-312
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• 1994

Interictal single photon emission computed tomography of regional cerebral blood flow (rCBF SPECT) in 18 intractable temporal lobe epilepsy patients(8 male and 10 female patients: average 23.5 years old) were compared with 2.0 T magnetic resonance imaging (MRI). And surgical outcome was analysed with the findings, symptom duration and lateralization of temporal lobe. Preoperatively rCBF SPECT was done in all 18 patients with intravenous injection of 740 MBq 99mTc-HMPAO. MRI was also done preoperatively in 13 patients. Surgical outcome was classified by Engel's outcome classification(four-part classification recommended at the first Palm Desert conference). rCBF SPECT detected correctly lateralising abnormality of temporal lobe hypoperfusion in 13/18(72.2%), contralateral temporal lobe hypoperfusion in 2/18(11.1%) and showed no def-inite abnormality in 3/18(16.7%). The positive predictive value of unilateral temporal lobe hypoperfusion was 87%. MRI detected correct localising abnormality in 8/13(61.5%), such as hippocampal atrophy(7/13), asymmetric temporal horn(6/13), anterior temporal lobe atrophy(1/13), increased signal intensity from hippocampus(1/13) and calcific density(1/13), and no abnormal finding was noted in 5/13(38.5%). There was no false positive findings and the positive predictive value of MRI was 100%. Only 2 cases showed same lateralization findings in rCBF SPECT and MRI. There was no significant correlation between symptom duration and no abnormal findings on SPECT or MRI. Surgical outcome showed class I in 15/18(83.3%), and class II in 2/18(11.1%). One case of no abnormal finding in both SPECT and MRI showed class III surgical outcome. No class IV surgical outcome was noted. Surgical outcome, lateralization of epileptic focus in temporal lobe and abnormal findings in rCBR SPECT or MRI were not significantly correlated.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.443-450
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• 2009

Purpose: Conventional image reconstruction uses simplified physical models of projection. However, real physics, for example 3D reconstruction, takes too long time to process all the data in clinic and is unable in a common reconstruction machine because of the large memory for complex physical models. We suggest the realistic distributed memory model of fast-reconstruction using parallel processing on personal computers to enable large-scale technologies. Materials and Methods: The preliminary tests for the possibility on virtual manchines and various performance test on commercial super computer, Tachyon were performed. Expectation maximization algorithm with common 2D projection and realistic 3D line of response were tested. Since the process time was getting slower (max 6 times) after a certain iteration, optimization for compiler was performed to maximize the efficiency of parallelization. Results: Parallel processing of a program on multiple computers was available on Linux with MPICH and NFS. We verified that differences between parallel processed image and single processed image at the same iterations were under the significant digits of floating point number, about 6 bit. Double processors showed good efficiency (1.96 times) of parallel computing. Delay phenomenon was solved by vectorization method using SSE. Conclusion: Through the study, realistic parallel computing system in clinic was established to be able to reconstruct by plenty of memory using the realistic physical models which was impossible to simplify.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.46-55
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• 1992

The pathophysiology of developmental language disorder is a highly controversial matter. In order to investigate the neural mechanisms involved in developmental language disorders, the authors studied three dimensional regional cerebral blood flow(rCBF) using Tc-99mH-MPAO in 42 children with developmental language disorders. The results are summarized as follows : 1) 61.9% (26/42) of this series revealed decreased perfusion in SPECT. 2) Regions of hypoperfusion were seen in cerebral cortex(47.6%, 20/42), thalamus(33.3%, 14/42), basal ganglia(11.9%, 5/42) and cerebellum(7.1%, 3/42). This study suggests that developmental language disorder could be due to specific functional impairment of the local brain regions which could not detected by conventional investigations such as brain CT or EEG.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.27 no.1
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• pp.64-71
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• 2016

Objectives: The objective of this study was to examine the effects of osmotic-controlled release oral delivery system methylphenidate on changes in regional cerebral blood flow (rCBF) in children with attention-deficit hyperactivity disorder (ADHD) using single photon emission computed tomography (SPECT). Methods: A total of 26 children with ADHD (21 boys, mean age: $9.2{\pm}2.05$ years old) were recruited. Each ADHD participant was examined for changes in rCBF using technetium-99m-hexamethylpropylene amine oxime brain SPECT before and after 8 weeks methylphenidate medication. Brain SPECT images of pediatric normal controls were selected retrospectively. SPECT images of ADHD children taken before medication were compared with those of pediatric normal controls and those taken after medication using statistical parametric mapping analysis on a voxel-wise basis. Results: Before methylphenidate medication, significantly decreased rCBF in the cerebellum and increased rCBF in the right precuneus, left anterior cingulate, right postcentral gyrus, right inferior parietal lobule and right precentral gyrus were observed in ADHD children compared to pediatric normal controls (p-value<.0005, uncorrected). After medication, we observed significant hypoperfusion in the left thalamus and left cerebellum compared to pediatric normal controls (p-value<.0005, uncorrected). In the comparison between before medication and after medication, there was significant hyperperfusion in the superior frontal gyrus and middle frontal gyrus and significant hypoperfusion in the right insula, right caudate, right middle frontal gyrus, left subcallosal gyrus, left claustrum, and left superior temporal gyrus after methylphenidate medication (p-value<.0005, uncorrected). Conclusion: This study supports dysfunctions of fronto-striatal structures and cerebellum in ADHD. We suggest that methylphenidate may have some effects on the frontal lobe, parietal lobe, and cerebellum in children with ADHD.

• Journal of radiological science and technology
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• v.31 no.4
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• pp.389-399
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• 2008

Corrections of attenuation, scatter and resolution are important in order to improve the accuracy of single photon emission computed tomography (SPECT) image reconstruction. Especially, the heart movement by respiration and beating cause the errors in the corrections. Myocardial phantom is used to verify the correction methods, but there are many different parts in the current phantoms in actual human body. Therefore the results using a phantom are often considered apart from the clinical data. We developed a new phantom that implements the human body structure around the thorax more faithfully. The new phantom has the small mediastinum which can simulate the structure in which the lung adjoins anterior, lateral and apex of myocardium. The container was made of acrylic and water-equivalent material was used for mediastinum. In addition, solidified polyurethane foam in epoxy resin was used for lung. Five different sizes of myocardium were developed for the quantitative gated SPECT (QGS). The septa of all different cardiac phantoms were designed so that they can be located at the same position. The proposed phantom was attached with liver and gallbladder, the adjustment was respectively possible for the height of them. The volumes of five cardiac ventricles were 150.0, 137.3, 83.1, 42.7 and 38.6ml respectively. The SPECT were performed for the new phantom, and the differences between the images were examined after the correction methods were applied. The three-dimensional tomography of myocardium was well reconstructed, and the subjective evaluations were done to show the difference among the various corrections. We developed the new cardiac and torso phantom, and the difference of various corrections was shown on SPECT images and QGS results.

• Radiation Oncology Journal
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• v.33 no.3
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• pp.188-197
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• 2015

Purpose: To investigate the patterns of care for patients with nasopharyngeal carcinoma (NPC) in South Korea. Materials and Methods: A multi-institutional retrospective study was performed (Korean Radiation Oncology Group [KROG] 11-06) on a total of 1,445 patients from 15 institutions. Results: Of the 1,445 patients, more than half were stages III (39.9%) and IV (35.8%). In addition to patterns of care, we also investigated trends over time with the periods 1988-1993, 1994-2002, and 2003-2011. The frequencies of magnetic resonance imaging and positron emission tomography-computed tomography were markedly increased in the third period compared to previous 2 periods. Concurrent chemoradiation (CCRT) was performed on 894 patients (61.9%), neoadjuvant chemotherapy on 468 patients (32.4%), and adjuvant chemotherapy on 366 patients (25.3%). Of stage II-IV patients, CCRT performed on 78.8% in 2003-2011 compared to 15.0% in 1988-1993. For patients treated with CCRT, cisplatin was the most commonly used agent in 81.3% of patients. Over the periods of time, commonly used radiotherapy (RT) techniques were changed from 2-dimensional RT (1988-1993, 92.5%) to 3-dimensional RT (2003-2011, 35.5%) or intensity-modulated RT (IMRT; 2003-2011, 56.5%). Median RT doses given to primary tumors, high-risk lymphatics, and low-risk lymphatics were 70.0 Gy, 58.1 Gy, and 48.0 Gy, respectively. Adoption of IMRT increased the dose per fraction and escalated total radiation dose. Conclusion: Assessment of the patterns of care for NPC patients in South Korea demonstrated that management for NPC including diagnostic imaging, treatment regimen, RT techniques and dose schedule, advanced in accordance with the international guidelines.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.201-208
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• 2008

Purpose: We aimed to assess the role of positron emission tomography using fluorodeoxyglucose (FDG-PET) in the diagnosis of recurrence or the assessment of therapeutic response in cervical and ovarian cancer patients through making a comparison between FDG-PET, abdominal computed tomography (CT) and serum tumor marker. Materials and methods: We included 103 cases (67 patients) performed FDG-PET and abdominal CT. There were 42 cervical cancers and 61 ovarian cancers. We retrospectively reviewed the interpretations of PET and CT images as well as the level of tumor marker. We calculated their sensitivity, specificity, positive predictive value and negative predictive value for these three modalities. And then we analyzed the differences between these three modalities. Results: Tumor recurrences were diagnosed in 37 cases (11 cervical cancers and 26 ovarian cancers). For PET, CT and tumor marker, in cervical cancer group, sensitivity was 100% (11/11), 54.5% (6/11) and 81.1% (9/11), respectively. And specificity was 93.6% (29/31), 93.6% (29/31) and 100% (31/31). In ovarian cancer group, sensitivity was 96.2% (25/26), 84.6% (22/26) and 80.8% (21/26), and specificity was 94.3% (33/35), 94.3% (33/35), 94.3% (33/35), PET was highly sensitive to detect the intraperitoneal and extraperitoneal metastasis with the help of the CT images to localize the lesions. However, CT had limitations in differentiation of the recurrent tumor from benign fibrotic tissue, identification of viable tumors at the interface of tissues, and detecting extraperitoneal lesions. Conclusion: FDG-PET can be an essential modality to detect the recurrent or residual tumors in gynecologic cancer patients because of its great field of the application and high sensitivity.