• 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.

• The Korean Journal of Nuclear Medicine
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• v.33 no.6
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• pp.519-526
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• 1999

Purpose: This study was designed to evaluate the usefulness of a technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) single photon emission computed tomography (SPECT) performed on transplanted kidney. Materials and Methods: Thirty renal transplant patients were included in this study. Planar scan was performed for 30 minutes using 555 MBq Tc-99m MAG3. A post-voiding SPECT scan was acquired on the third, seventh, fourteenth and twenty eighth day after transplantation. Results: SPECT scan showed interpretable image quality in 26 of 30 patients (86.7%) and 84 in 120 scans (70%). Fourteen of 26 patients with interpretable SPECT image showed decreased or increased radioactivity, but only 5 had abnormal findings on the planar scan. Focal SPECT defects were seen in allografts with normal function (n=3), acute tubular necrosis (n=3), and acute rejection (n=2). The defects are thought to reflect focally underperfused renal parenchyme or, in normal allografts, an artifact from uneven radioactivity distribution. Four of 10 patients with renal arterial variation showed focally decreased radioactivity and SPECT helped guide funker studies that confirmed the exact cause. Five of 10 patients with acute tubular necrosis or acute rejection showed focally decreased radioactivity, but its relation to the patients' clinical course was not clear. Focally increased radioactivity was observed in 5 allografts with normal function and 1 with double ureter in which local clearance delay was observed. Conclusion: Tc-99m MAG3 SPECT renal scan can detect additional focal abnormalities compared to planar scan. Further study is necessary to elucidate the exact clinical significance of the SPECT findings.

• Clinical and Experimental Pediatrics
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• v.53 no.4
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• pp.603-606
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• 2010

Paraneoplastic limbic encephalitis, a remote effect of cancer without nervous system metastasis, is rare, especially in childhood. Here, we report a case of paraneoplastic limbic encephalitis associated with an ovarian mature teratoma in an adolescent girl. The 15-year-old girl developed neuropsychiatric symptoms, memory loss, seizures, and unconsciousness. Cerebrospinal fluid analysis and brain magnetic resonance imaging (MRI) findings were normal, while single photon emission computed tomography imaging showed hypoperfusion in both temporal lobes. Ultrasound and MRI of the abdomen revealed a left ovarian cystic mass. The patient experienced a significant recovery of cognitive function after surgical resection of the tumor, which was pathologically identified as a mature ovarian teratoma, and treatment with intravenous immunoglobulin.

• 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.

• The Korean Journal of Nuclear Medicine
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• v.38 no.2
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• pp.180-189
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• 2004

Although the outcome of cancer patients after cytotoxic chemotherapy is related diverse mechanisms, multidrug resistance (MDR) for chemotherapeutic drugs due to cellular P-glycoprotein (Pgp) or multidrug-resistance associated protein (MRP) is most important factor in the chemotherapy failure to cancer. A large number of pharmacologic compounds, including verapamil, quinidine, tamoxifen, cyclosporin A and quinolone derivatives have been reported to overcome MDR. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are available for the detection of Pgp and MRP-mediated transporter. $^{99m}Tc$-MIBI and other $^{99m}Tc$-radiopharmaceuticals are substrates for Pgp and MRP, and have been used in clinical studies for tumor imaging, and to visualize blockade of PgP-mediated transport after modulation of Pgp pump. Colchicine, verapamil and daunorubicin labeled with $^{11}C$ have been evaluated for the quantification of Pgp-mediated transport with PET in vivo and reported to be feasible substrates with which to image Pgp function in tumors. Leukotrienes are specific substrates for MRP and $N-[^{11}C]acetyl-leukotriene$ E4 provides an opportunity to study MRP function non-invasively in vivo. SPECT and PET pharmaceuticals have successfully used to evaluate pharmacologic effects of MDR modulators. Imaging of MDR and reversal of MDR with bioluminescence in a living animal is also evaluated for future clinical trial. We have described recent advances in molecular imaging of MDR and reviewed recent publications regarding feasibility of SPECT and PET imaging to study the functionality of MDR transporters in vivo.

• The Korean Journal of Nuclear Medicine
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• v.34 no.6
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• pp.445-455
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• 2000

Purpose: We evaluated the distribution of hypoperfusion in patients with traumatic brain injury (TBI) and the relationship of thalamic hypoperfusion to severity of cognitive and behavioral sequelae. Materials and Methods: Tc-99m ECD SPECT and MRI were performed in 103 patients (M/F=81/22, mean age $34.7{\pm}15.4$ yrs) from 0.5 to 55 months (mean 10.3 months) after TBI. The patients were divided into three groups showing no abnormalities (G1), focal (G2) and diffuse injury (G3) on MRI. Psychometric tests assessed 11 cognitive or behavioral items. In all patients, we evaluated the distribution of hypoperfused areas in SPECT, and in 57/103 patients, neuropsychological (NP) abnormalities in patients with thalamic hypoperfusion were compared with those of patients without thalamic hypoperfusion. Results: The perfusion deficits were most frequently located in the frontal lobe (G1, 42.3%: G2 34.5%: G3 33.3%), temporal lobe ($24{\sim}26%$) thalami ($21{\sim}22.4%$), parietal and occipital lobe (${\leq}10%$). Numbers of NP abnormalities in the cases of cortical hypoperfusion with or without concomitant thalamic hypoperfusion were following: the former $4.7{\pm}1.5$ and the latter $3.2{\pm}1.4\;in\;G1,\;5.0{\pm}1.1\;and\;4.8{\pm}1.2\;in\;G2,\;6.8{\pm}1.8\;and\;6.3{\pm}1.1\;in\;G3$, respectively. This difference according to thalamic hypoperfusion was significant in G1 (p=0.002), but was not significant in G2 or G3. Conclusion: SPECT in patients with TBI had demonstrated hypoperfusion mostly involving the frontal, temporal and thalami. In normal group on MRI, frontal hypoperfusion was more prominent than that of any other group, Furthermore in this group, SPECT could predict severity of NP outcome by concomitant thalamic hypoperfusion with cerebral cortical abnormalities.

• The Journal of Korean Medicine
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• v.27 no.3 s.67
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• pp.187-200
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• 2006

Objectives: Acupuncture has been applied in Asia for thousands of years, especially to rehabilitation after stroke. It has been reported that acupuncture increased cerebral blood supply and stimulated the functional activity of brain nerve cells shown by using brain imaging techniques. This study was to evaluate the effect of GB 34-GB 39 electro-acupuncture (EA) on regional cerebral blood flow (rCBF) in stroke patients and normal volunteers using single photon emission computed tomography (SPECT). Methods: The study procedure was divided into two parts: patients and volunteers studies. For the patients study, ten ischemic stroke patients (3 males, 7 females, mean age $68.5{\pm}8.9$ years old) were selected. Baseline brain SPECT was done with triple head gamma camera (MultiSPECT3, Siemens, USA) after intravenous administration of 1,110 MBq of $^{99m}Tc-ECD$. Fifteen-minute EA at GB 34 and GB 39 were applied on the affected limb. The same dose of $^{99m}Tc-ECD$ was injected during the EA, and the second set of SPECT images wasobtained. Using the computer software (ICON 7.1, Siemens, USA), 3 SPECT slices (upper, middle, lower) surrounding the brain lesion were selected and each slice was divided into 10-16 brain regions. Asymmetry indexes (AI) were analyzed in each brain region. We regarded over 10% changes of AI between before and after EA as significance. For the volunteers study, 10 healthy human volunteers (5 males, 5 females, mean age $28.1{\pm}6$ years old) were selected. In the resting state, $^{99m}Tc-ECD$ brain SPECT scans were performed. On the 7th day after the resting examination, 15 minute EA was applied at GB 34 and GB 39 on the right side of the subjects. Immediately after EA, the second SPECT images were obtained inthe same manner as the resting state. Significant increases and decreases of rCBF after EA were estimated by comparing their SPECT images with those of the resting state using paired t statistics at every voxel, which were analyzed by statistical parametric mapping with a threshold of p = 0.01, uncorrected (extent threshold: k=100 voxels). Results: In stroke patients, six of the eight (75%) had significantly increased perfusion in post-acupuncture scans compared to their baseline state. In normal volunteers, GB 34-GB GB EA increased rCBF in both hemispheres including right ventral posterior cingulate (Brodmann area (BA) 23), left superior temporal, anterior transverse temporal (BA 22, 41), left parastriate, peristriate (BA 18, 19), right occipitotemporal, angular (BA 37, 39), left rostral postcentral, caudal postcentral and preparietal (BA 2, 3, 5). However GB 34-GB 39 EA decreased rCBF in the right hemisphere including triangular and middle frontal lobes. Conclusions: The results demonstrated that OB 34-GB 39 EA increased cerebral perfusion in ischemic stroke patients and increased rCBF grossly in temporal lobes of normal volunteers. It is also suggested that there may be a correlation between the GB meridian and the territory of the middle cerebral artery.

• Tuberculosis and Respiratory Diseases
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• v.43 no.5
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• pp.720-727
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• 1996

Objectives: $^{201}TI$ - chloride, $^{99m}Tc$ - MIBI, $^{99m}Tc$(V) - DMSA SPECT has been used in distinguishing lung cancer from benign lesion. To compare the diagnostic efficacy of SPECT with these tumor - seeking agents, we perfonned three consecutive SPECT using $^{201}TI$, $^{99m}Tc$ - MIBI, $^{99m}Tc$(V) - DMSA in same subjects with a solitary pulmonary lesion. Methods: SPECT was carried out at 10min and 3hr for $^{201}TI$ after injection of 20mCi, and 2hr for $^{99m}Tc$ - MIBI and $^{99m}Tc$(V) - DMSA after injection of 20mCi, respectively, in 37 patients with a solitary pulmonary lesion(27 lung cancer and 10 benign diseases). In patients showing visual uptake on lesion site, we obtained the lesion - to - background(target lesion/contralateral normal lung) uptake ratio from transverse slice for each radionuclide and also calculated the retention index for $^{201}TI$. Results: The diagnostic sensitivity of $^{201}TI$, $^{99m}Tc$ - MIBI and $^{99m}Tc$(V) - DMSA SPECT to lung cancer was 100%, 96% and 73%, and the specificity was 40%, 70% and 70%, respectively. The low specificities for these agents were mainly due to high positive uptake in patients with active pulmonary tuberculosis. There were no significant differences in uptake ratios and retention index between malignant and benign lesions, and among the histologic types of lung cancer. Conclusion : $^{201}TI$ and $^{99m}Tc$ - MIBI showed higher sensitivity than $^{99m}Tc$(V) - DMSA for detecting lung cancer, but was of limited usefulness in distinguishing lung cancer from benign lesion due to low specificity, especially in area with a high prevalence of active pulmonary tuberculosis.

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.247-261
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• 1999

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO, Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age $40.3{\pm}24.9$ years, range 4 to 82 years) were underwent rost/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in (rental, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018, rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was $29.9{\pm}12.9%$. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.522-527
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• 2004

Purpose: The purpose of this study was to evaluate the usefulness of single photon emission computed tomography (SPECT) of bone using Tc-99m MDP in the diagnosis of osteoporotic vertebral fractures. Materials and Methods: Thirty two patients with osteoporotic vertebral fracture were included in this study (mean age: $67{\pm}8$, male: 5, female: 27). Seventy nine vertebral fractures were detected (38 thoracic/thoracolumbar lesions and 41 lumbar lesions), which were classified by type of deformity (wedge, biconcave or compression). The patterns and locations of increased uptakes were examined and analyzed. Results: Forty seven wedge fractures, 20 biconcave fractures and 12 compression fractures were found. Diffuse and asymmetric uptakes were common in fractured bodies. More than one uptake were examined in 69 posterior elements of fractured vertebrae (87.3%) including 40 of 47 wedge fractures (85.1%), 17 of 20 biconcave fractures (85.0%) and 12 of 12 compression fractures (100%). Wedge fractures were predominant fracture in thoracic/thoracolumbar spine whereas incidence of biconcave or compression type war similar to that of wedge fracture in lumbar spine (p=0.04). Spinous process uptake was more frequently seen in lumbar lesions than thoracic/thoracolumbar lesions (p=0.009). Facet joint uptake in biconcave fracture was more common in lumbar spine (92.3%) than thoracic/thoracolumbar spine (57.1%). Spinous process uptake in biconcave fracture was also more frequently detected in lumbar spine (p=0.043). Conclusion: Bone SPECT was useful in the evaluation of osteoporotic vertebral fracture, especially posterior elements of vertebrae.