• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.81-86
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• 2012

Purpose : Combined MR/PET scanners that use the MRI for PET AC face the challenge of absent surface coils in MR images and thus cannot directly account for attenuation in the coils. To make up for the weak point of MR attenuation correction, Three Modality System (PET/CT +MR) were used in Severance hospital. The goal of this work was to investigate the effects of MR Torso Coil on CT attenuation correction for PET. Materials and Methods : PET artifacts were evaluated when the MR Torso Coil was present of CTAC data with changing various kV and mA in uniformity water phantom and 1994 NEMA cylinderical phantom. They evaluated and compared the following two scenarios: (1) The uniform cylinder phantom and the MR Torso Coil scanned and reconstructed using CT-AC; (2) 1994 NEMA cylinderical phantom and the MR Torso Coil scanned and reconstructed using CT-AC. Results : Streak artifacts were present in CT images containing the MR Torso Coil due to metal components. These artifacts persisted after the CT images were converted for PET-AC. CT scans tended to over-estimate the linear attenuation coefficient when the kV and mA is increasing of the metal components when using conventional methods for converting from CT number. Conclusion : The presence of MR coils during PET/CT scanning can cause subtle artifacts and potentially important quantification errors. Alternative CT techniques that mitigate artifacts should be used to improve AC accuracy. When possible, removing segments of an MR coil prior to the PET/CT exam is recommended. Further, MR coils could be redesigned to reduce artifacts by rearranging placement of the most attenuating materials.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.122-126
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• 2010

Purpose: F-18-FPCIT that shows strong familiarity with DAT located at a neural terminal site offers diagnostic information about DAT density state in the region of the striatum especially Parkinson's disease. In this study, we altered the iteration and subset and measured SUV${\pm}$SD and Contrasts from phantom images which set up to specific iteration and subset. So, we are going to suggest the appropriate range of the iteration and subset. Materials and Methods: This study has been performed with 10 normal volunteers who don't have any history of Parkinson's disease or cerebral disease and Flangeless Esser PET Phantom from Data Spectrum Corporation. $5.3{\pm}0.2$ mCi of F-18-FPCIT was injected to the normal group and PET Phantom was assembled by ACR PET Phantom Instructions and it's actual ratio between hot spheres and background was 2.35 to 1. Brain and Phantom images were acquired after 3 hours from the time of the injection and images were acquired for ten minutes. Basically, SIEMENS Bio graph 40 True-point was used and True-X method was applied for image reconstruction method. The iteration and Subset were set to 2 iterations, 8 subsets, 3 iterations, 16 subsets, 6 iterations, 16 subsets, 8 iterations, 16 subsets and 8 iterations, 21 subsets respectively. To measure SUVs on the brain images, ROIs were drawn on the right Putamen. Also, Coefficient of variance (CV) was calculated to indicate the uniformity at each iteration and subset combinations. On the phantom study, we measured the actual ratio between hot spheres and back ground at each combinations. Same size's ROIs were drawn on the same slide and location. Results: Mean SUVs were 10.60, 12.83, 13.87, 13.98 and 13.5 at each combination. The range of fluctuation by sets were 22.36%, 10.34%, 1.1%, and 4.8% respectively. The range of fluctuation of mean SUV was lowest between 6 iterations 16 subsets and 8 iterations 16 subsets. CV showed 9.07%, 11.46%, 13.56%, 14.91% and 19.47% respectively. This means that the numerical value of the iteration and subset gets higher the image's uniformity gets worse. The range of fluctuation of CV by sets were 2.39, 2.1, 1.35, and 4.56. The range of fluctuation of uniformity was lowest between 6 iterations, 16 subsets and 8 iterations, 16 subsets. In the contrast test, it showed 1.92:1, 2.12:1, 2.10:1, 2.13:1 and 2.11:1 at each iteration and subset combinations. A Setting of 8 iterations and 16 subsets reappeared most close ratio between hot spheres and background. Conclusion: Findings on this study, SUVs and uniformity might be calculated differently caused by variable reconstruction parameters like filter or FWHM. Mean SUV and uniformity showed the lowest range of fluctuation at 6 iterations 16 subsets and 8 iterations 16 subsets. Also, 8 iterations 16 subsets showed the nearest hot sphere to background ratio compared with others. But it can not be concluded that only 6 iterations 16 subsets and 8 iterations 16 subsets can make right images for the clinical diagnosis. There might be more factors that can make better images. For more exact clinical diagnosis through the quantitative analysis of DAT density in the region of striatum we need to secure healthy people's quantitative values.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.73-76
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• 2009

Purpose: Bone mineral densitometry test region advised by ISCD (International Society for Clinical Densitometry) is both site in case of femur, whereas our medical center measures left femur except for few extraordinary cases. It is said that right-handers had higher mean femur BMD in the left side than in the right side, but the factor influence the femur BMD is unknown. Thus, we investigate whether testing left femur only is a adequate clinical diagnosis. Materials and Methods: Subjects were 209 right-handers and 20 left-handers patient in Asan Medical Center from July to August, 30 to 70 years of age ($51{\pm}6.7$). Subjects fill out the questionnaire on hand preference and taking regular exercise. Total BMDs of bilateral femur were measured with GE Lunar Prodigy advance densitometer, and the statistical soft ware SPSS 12.0 for windows was used for statistical analysis. Results: In the total sample of the exercise group (n=127), the difference of both femur mean BMDs are $0.001{\pm}0.127\;g/cm^2$ and the non-exercise group's (n=102) both femur difference is $0.002{\pm}0.126\;g/cm^2$, there is no significant difference. And in exercise group, classified according to hand preference, each t-value is shown at right handers (n=114) are 0.65, left handers (n=13) are -0.39. Also, In non-exercise group, right handers (n=95) are -0.78, left handers (n=7) are -0.64. In the 95% confidence limit, there was no statistically significant difference (p>0.05). Conclusions: In recently researchs, there have been differences between both femurs according to hand preference. However, Our study have no significant difference both femurs BMDs. Therefore we suggest that BMD measurement of femur has no problem only one side, except for particular case like femur operation.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.9-14
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• 2009

Purpose: Nowadays in the nuclear medicine, many studies and efforts are being made to reduce the scan time, as well as the waiting time to be needed to execute exams after injection of radionuclide medicines. Several methods are being used in clinic, such as developing new radionuclide compounds that enable to be absorbed into target organs more quickly and reducing acquisition scan time by increase the number of Gamma Camera detectors to examine. Each medical equipment manufacturer has improved the imaging process techniques to reduce scan time. In this paper, we tried to analyze the difference of image quality between FBP, 3D OSEM reconstruction methods that commercialized and being clinically applied, and Astonish reconstruction method (A kind of Iterative fast reconstruction method of Philips), also difference of image quality on scan time. Material and Methods: We investigated in 32 patients that examined the Bone SPECT from June to July 2008 at department of nuclear medicine, ASAN Medical Center in Seoul. 40sec/frame and 20sec/frame images were acquired that using Philips‘ PRECEDENCE 16 Gamma Camera and then reconstructed those images by using the Astonish (Philips’ Reconstruction Method), 3D OSEM and FBP methods. The blinded test was performed to the clinical interpreting physicians with all images analyzed by each reconstruction method for qualitative analysis. And we analyzed target to non target ratio by draws lesions as the center of disease for quantitative analysis. At this time, each image was analyzed with same location and size of ROI. Results: In a qualitative analysis, there was no significant difference by acquisition time changes in image quality. In a quantitative analysis, the images reconstructed Astonish method showed good quality due to better sharpness and distinguish sharply between lesions and peripheral lesions. After measuring each mean value and standard deviation value of target to non target ratio with 40 sec/frame and 20sec/frame images, those values are Astonish (40 sec-$13.91{\pm}5.62$ : 20 sec-$13.88{\pm}5.92$), 3D OSEM (40 sec-$10.60{\pm}3.55$ : 20 sec-$10.55{\pm}3.64$), FBP (40 sec-$8.30{\pm}4.44$ : 20 sec-$8.19{\pm}4.20$). We analyzed target to non target ratio from 20 sec and 40 sec images. And we analyzed the result, In Astonish (t=0.16, p=0.872), 3D OSEM (t=0.51, p=0.610), FBP (t=0.73, p=0.469) methods, there was no significant difference statistically by acquisition time change in image quality. But FBP indicates no statistical differences while some images indicate difference between 40 sec/frame and 20 sec/frame images by various factors. Conclusions: In the circumstance, try to find a solution to reduce nuclear medicine scan time, the development of nuclear medicine equipment hardware has decreased while software has marched forward at a relentless. Due to development of computer hardware, the image reconstruction time was reduced and the expanded capacity to restore enables iterative methods that couldn't be performed before due to technical limits. As imaging process technique developed, it reduced scan time and we could observe that image quality keep similar level. While keeping exam quality and reducing scan time can induce the reduction of patient's pain and sensory waiting time, also accessibility of nuclear medicine exam will be improved and it provide better service to patients and clinical physician who order exams. Consequently, those things make the image of department of nuclear medicine be improved. Concurrent Imaging - A new function that setting up each image acquisition parameter and enables to acquire images simultaneously with various parameters to once examine.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.101-104
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• 2010

Purpose: Raynaud scan is divided to flow, blood pool and local-delay image. Usually, we evaluate comparison through blood pool and local-delay image. We will evaluate about usability when comparative observe blood image and local-delay image in Raynaud scan that used $^{201}Tl$ as making flow image to one sheet of images. Materials and Methods: We have selected 29 Raynaud phenomenon patients aged 14~68 years who visited department of vascular surgery between Feb. 2008 and Aug. 2009. An intravenous injection $^{201}Tl$ of 111 MBq (3 mCi) to opposite side diagonal line limbs above an internal auditing department. Equipment used Philips gamma camera forte A-Z, and collimator used LEHR. Matrix size set up to each $64{\times}64$, $128{\times}128$, $256{\times}256$ and zoom factor used to full field. Protocol of dynamic is 2 second to 155 frames. Blood pool and delay count to 300 second. We set up ROI by a foundation to data acquired in PEGASYS processing program. Each results were analyzed with the SPSS 12.0 statistical software. Results: Each averages of count ratio (Rt / Lt) to have been given at composite image, a blood pool image, delay images analyzed at Raynaud phenomenon patients is $1.25{\pm}0.39$, $1.20{\pm}0.33$, $1.11{\pm}0.17$. The sample analysis results of blood pool image and delay image contented itself with p<0.029. Also, there don't have been each difference, and blood pool image, delay image regarding composite image was able to know. Conclusion: We were able to give help for comparison to evaluate a blood pool image and a local delay image at the Raynaud scan which used $^{201}Tl$ while making a flow image to one sheet image. Identification to be visual too was possible. If you are proceeded a researcher that there was further depth, you are more appropriate for, and you may get useful information.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.20-24
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• 2009

Objective: In this study, the differences between two reconstruction methods were analyzed by comparing image uniformity and contrast according to Iteration and Subset, which were altered through the Iterative method and True X method, used in Siemens' PET/CT studies. Methods: The Phantom images were obtained by exposure for two minutes per one bed. To determine the image uniformity, the Coefficient of variance was used. Also, in order to compare the contrast value, we measured and analyzed the ratio of the SUV mean of Phantom image's hot spheres and the background. Results: Under the same reconstruction conditions (Iteration and Subset) of CV, the Iterative method was higher than the True X method. In the comparison of the SUV mean ratio of the background and hot sphere, the True X method had a closer rate than the Iterative method. Conclusion: The newly developed True X reconstruction method is better than the previously used Iterative method in terms of uniformity and contrast. However, the date for this study was only obtained using the Phantom device. In order to obtain more accurate and useful information from the experiment, further research should be conducted. Also, it is necessary to find the appropriate standards for Iteration and Subset for further experimentation.

• The Korean Journal of Nuclear Medicine
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• v.36 no.3
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• pp.166-176
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• 2002

Purpose: The purpose of this study is to investigate the effects of visual activation and quantitative analysis of regional cerebral blood flow. Visual activation was known to increase regional cerebral blood flow in the visual cortex in occipital lobe. We evaluated that change in the distribution of $^{99m}Tc-HMPAO$ (Hexamethyl propylene amine oxime) to reflect in regional cerebral blood flow. Materials and Methods: The six volunteers were injected with 925 MBq (mean ages: 26.75 years, n=6, 3men, 3women) underwent MRI and $^{99m}Tc-HMPAO$ SPECT during a rest state with closed eyes and visual stimulated with 8 Hz LED. We delineate the legion of interest and calculated the mean count per voxel in each of the fifteen slices to quantitative analysis. The ROI to whole brain ratio and regional index was calculated pixel to pixel subtraction visual non-activation image from visual activation image and constructed brain map using a statistical parameter map (SPM99). Results: The mean regional cerebral blood flow was increased due to visual stimulation. The increase rate of the mean regional cerebral blood flow which of the activation region in primary visual cortex of occipital lobe was $32.50{\pm}5.67%$. The significant activation sites using a statistical parameter of brain constructed a rendering image and image fusion with SPECT and MRI. Conclusion: Visual activation was revealed significant increase through quantitative analysis in visual cortex. Activation region was certified in Talairach coordinate and primary visual cortex (Ba17),visual association area (Ba18,19) of Brodmann.

• The Korean Journal of Nuclear Medicine
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• v.36 no.3
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• pp.177-184
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• 2002

Purpose: Ultrasonography and $^{99m}-Tc-MIBI$ scintimammography were validated as useful diagnostic tools for primary breast cancer. However, ultrasound has the problem of low specificity. We compared the diagnostic usefulness of ultrasound with $^{99m}-Tc-MIBI$ scintimammography in the diagnosis of breast cancer. Materials and Methods: This study included 174 patients who had ultrasound and $^{99m}-Tc-MIBI$ scintimammography peformed on breast masses from 1999 to 2000. The pathologic results were obtained by surgery or FNAB. Results: Among the 174 patients, malignant breast disease numbered 117 and benign breast disease numbered 57. Ultrasound revealed 88 TP, 9 FN, 8 FP, 34 TN, and 35 indeterminate cases. $^{99m}-Tc-MIBI$ scintimammography revealed 91 TP, 25 FN, 9 FP, and 48 TN. The sensitivity, specificity, positive predictive value, and negative predictive value of Ultrasound were 66.7%, 44.2%, 67.2%, and 43.6% respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of $^{99m}-Tc-MIBI$ scintimammography were 77.8%, 84.2%, 91%, and 64.9% respectively. Among the 35 indeterminate ultrasound cases, $^{99m}-Tc-MIBI$ scintimammography revealed 13 TP, 15 TN, and 7 FP Conclusion: $^{99m}-Tc-MIBI$ Scintimammography was more sensitive and specific than ultrasound for the detection of primary breast cancer and provided more useful information in cases of indeterminate ultrasound findings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.442-447
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• 2017

The purpose of this study was to establish norm-referenced criteria for the isokinetic strength of the elbow joint in Korean high school baseball players. Two hundred and one high school baseball players participated in this study, none of whom had any medical problem with their upper limbs. The elbow flexion/extension test was conducted four times at a speed of $60^{\circ}/sec$. The HUMAC NORM (CSMI, USA) system was used to obtain the values of the peak torque and peak torque per body weight. The results were presented as norm-referenced criterion valuesusing the 5-point scale of Cajori which consists of five stages (6.06%, 24.17%, 38.30%, 24.17%, and 6.06%). In the results of this study, the peak torques of the elbow (flexor and extensor?) at an angular velocity of $60^{\circ}/sec$ were $37.88{\pm}8.14Nm$ and $44.59{\pm}11.79Nm$, and the peak torque per body weight of the elbow (flexor and extensor?) were $50.06{\pm}8.66Nm$ and $58.28{\pm}12.84Nm$, respectively. The reference values of the peak torque and peak torque per body weight of the elbow flexor and extensor were setat an angular velocity of $60^{\circ}/sec$. On the basis of the results analyzed in this study, the following conclusions were drawn. There is a lack of proper studies on the elbow joint strength, even though the most common injury in baseball players occurs in the elbow joint. Therefore, we need to establish a standard muscle strength in order to prevent elbow joint injuries and improve their performance. The criteria for the peak torque and peak torque per body weight established here in will provide useful information for high school baseball players, baseball coaches, athletic trainers and sports injury rehabilitation specialists in injury recovery and return to rehabilitation, which can beutilized as objective clinical assessment data.

• Korean Journal of Psychosomatic Medicine
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• v.19 no.1
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• pp.20-27
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• 2011

Objectives: The present study aims to investigate the effects of physical illness on depression in North Korean Defectors. Methods: One hundred forty-four North Korean Defectors(20 males, 124 females) and 376 South Koreans 133 males, 243 females) in Incheon Metropolitan areas participated the present study. Face-to-face interview was conducted for demographic information including presence of physical illnesses. To investigate depressive symptoms, all participants were required to complete the Center for Epidemiologic Studies-Depression scale (CES-D). Results: After controlling gender, age, marital status, educational year, employment status and physical illness, North Korean Defectors showed higher CES-D score than South Koreans(${\beta}$=0.449, p<0.001). Within North Korean Defectors, the presence of physical illnesses independently was related to higher CES-D score(${\beta}$=0.243, p<0.001). However, within South Koreans, the presence of physical illnesses did not significantly predict CES-D score. North Korean Defectors with physical illness have higher CES-D score than North Korean Defectors without physical illness($26.8{\pm}13.8$ versus $19.7{\pm}12.7$). However, there was no significant differences of CES-D score between South Koreans with physical illness and South Koreans without physical illness($10.3{\pm}9.8$ versus $9.3{\pm}8.8$). Conclusion: Compared to South Koreans, North Korean Defector showed higher depressive symptoms independently from gender, age, education, employment, marriage. In addition, only North Korean Defectors showed the relationship between depression and physical illness. Our study suggests that depression should be assessed when North Korean Defectors have physical illness.