• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.133-137
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• 2010

Purpose: Breast cancer is known to be more vulnerable to bone metastasis and lymph node metastasis than other types of cancer, and nuclear examinations whole body bone scan and lymphoscintigraphy are performed commonly before and after breast cancer operation. In case whole body bone scan is performed on the day before lymphoscintigraphy, the radiopharmaceutical taken into and remaining in the bones provides anatomical information for tracking and locating sentinel lymph nodes. Thus, this study purposed to examine how much bone density affects in locating sentinel lymph nodes. Materials and Methods: The subjects of this study were 22 patients (average age $52{\pm}7.2$) who had whole body bone scan and lymphoscintigraphy over two days in our hospital during the period from January to December, 2009. In the blind test, 22 patients (average age $57{\pm}6.5$) who had lymphoscintigraphy using $^{57}Co$ flood phantom were used as a control group. In quantitative analysis, the relative ratio of the background to sentinel lymph nodes was measured by drawing ROIs on sentinel lymph nodes and the background, and in gross examination, each of a nuclear physician and a radiological technologist with five years' or longer field experience examined images through blind test in a five-point scale. Results: In the results of quantitative analysis, the relative ratio of the background to sentinel lymph nodes was 14.2:1 maximum and 8.5:1 ($SD{\pm}3.48$) on the average on the front, and 14.7:1 maximum and 8.5:1 ($SD{\pm}3.42$) on the average on the side. In the results of gross examination, when $^{57}Co$ flood phantom images were compared with images containing bones, the score was relative high as 3.86 ($SD{\pm}0.35$) point for $^{57}Co$ flood phantom images and 4.09 ($SD{\pm}0.42$) for bone images. Conclusion: When whole body bone scan was performed on the day before lymphoscintigraphy, the ratio of the background to sentinel lymph nodes was over 10:1, so there was no problem in locating lymph nodes. In addition, we expect to reduce examination procedures and improve the quality of images by indicating the location of sentinel lymph nodes using bone images as body contour without the use of a source.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.492-497
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• 2004

Purpose: it is very important to differentiate breast cancer from benign mass. There are many reports to evaluate the differential diagnosis under the several diagnostic tools. We evaluated the usefulness of mammography and Tc-99m MIBI scintimammography in the differential diagnosis of breast mass and correlated with pathologic findings. Materials and Methods: This study included 80 patients (a8e: 24-72, mean: 48.4) who underwent mammography and Tc-99m MIBI scintimammography for breast masses. Scintimammographies (anterior-posterior and lateral projections) were acquired in 10 minutes and 2 hours after intravenous injection of Tc-99m MIBI. four specialists in diagnostic radioloay and nuclear medicine evaluated the findings of breast masses under the mammography and Tc-99m MIBI scintimammography, and calculated the tumor to background (T/B) ratio. The pathologic results were obtained and we statistically analyzed the correlations between pathologic results and imaging findings under the mammography and Tc-99m MIBI scintimammography by chi-square and correlation test. Results: The sensitivity, specificity, positive predictive value, and negative predictive value of mammography for detection of breast cancer were 87.5%, 56.3%, 75.0%), and 75.0% respectively. 45 cases of 80 patients were suspicious for breast cancer under the Tc-99m MIBI scintimammography. 41 cases of 45 patients were confirmed as breast cancer and the remaining 4 cases were confirmed as benign masses. The sensitivity, specificity, positive predictive value and negative predictive value of Tc-99m MIBI scintimammography for detection of breast cancer were 85.4%, 87.5%, 91.1%, and 80.8% respectively. The sensitivity of scintimammography was lower than that of mammography for detection of breast cancer, however the specificity, positive predictive value, and negative predictive value were higher. In the benign mass, the mean T/B ratio in 10 minutes was $1.409{\pm}0.30$, and that in 2 hours was $1.267{\pm}0.42$. The maximal T/B ratio of benign mass in 10 minutes was $1.604{\pm}0.42$, and that in 2 hours was $1.476{\pm}0.50$. In the malignant mass, the mean T/B ratio in 10 minutes was $2.220{\pm}1.07$, and that in 2 hours was $1.842{\pm}0.75$. The maximal T/B ratio of malignant mass was $2.993{\pm}1.94$, and that in 2 hours was $2.480{\pm}1.34$. And the T/B ratio under the early and delayed images were meaningful. Conclusion: The scintimammography is useful diagnostic tool to differentiate breast cancer from benign mass, although the sensitivity of mammography for detection of breast mass is high. Especially, the use of the T/B ratio is helpful to diagnose breast cancer.

• Progress in Medical Physics
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• v.9 no.3
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• pp.163-173
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• 1998

Nuclear medicine emission computed tomography(ECT) can be very useful to diagnose early stage of neuronal diseases and to measure theraputic results objectively, if we can quantitate energy metabolism, blood flow, biochemical processes, or dopamine receptor and transporter using ECT. However, physical factors including attenuation, scatter, partial volume effect, noise, and reconstruction algorithm make it very difficult to quantitate independent of type of SPECT. In this study, we quantitated the effects of attenuation and scatter using brain SPECT and three-dimensional brain phantom with and without applying their correction methods. Dual energy window method was applied for scatter correction. The photopeak energy window and scatter energy window were set to 140ke${\pm}$10% and 119ke${\pm}$6% and 100% of scatter window data were subtracted from the photopeak window prior to reconstruction. The projection data were reconstructed using Butterworth filter with cutoff frequency of 0.95cycles/cm and order of 10. Attenuation correction was done by Chang's method with attenuation coefficients of 0.12/cm and 0.15/cm for the reconstruction data without scatter correction and with scatter correction, respectively. For quantitation, regions of interest (ROIs) were drawn on the three slices selected at the level of the basal ganglia. Without scatter correction, the ratios of ROI average values between basal ganglia and background with attenuation correction and without attenuation correction were 2.2 and 2.1, respectively. However, the ratios between basal ganglia and background were very similar for with and without attenuation correction. With scatter correction, the ratios of ROI average values between basal ganglia and background with attenuation correction and without attenuation correction were 2.69 and 2.64, respectively. These results indicate that the attenuation correction is necessary for the quantitation. When true ratios between basal ganglia and background were 6.58, 4.68, 1.86, the measured ratios with scatter and attenuation correction were 76%, 80%, 82% of their true ratios, respectively. The approximate 20% underestimation could be partially due to the effect of partial volume and reconstruction algorithm which we have not investigated in this study, and partially due to imperfect scatter and attenuation correction methods that we have applied in consideration of clinical applications.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.151-156
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• 2012

$^{18}F$-fluorodeoxyglucose ($^{18}F$-FDG) causes a significant amount of radioactivity retention in kidneys and urinary tract and degrades image quality and diagnostic performance. Diuretics are used to perform tests and prevent the urinary tract retention of $^{18}F$-FDG. The purpose of the study is to investigate how the diuretics affect images and excretion rates of $^{18}F$-FDG. The study consists of a group using diuretics for patients with no primary tumors or transfer lesions in kidneys according to PET/CT images, a group using physiological saline and the control group injecting only $^{18}F$-FDG and SUVs are measured by configuring interested areas for each group. Also, SUVs are compared and evaluated depending on the lasix injection after basic inspection and injecting $^{18}F$-FDG for quantitative analysis. The study shows that images with decreased background radioactivity and increased urine excretion due to using diuretics. However, an opposite result that there is no change in the amount of radioactivity in urine appears. The study concludes that the diuretics may decrease background radioactivity in the images but may not affect the $^{18}F$-FDG excretion.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.2
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• pp.36-40
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• 2011

Purpose: $^{18}F$-FDG injected dose to the patient is quite different between the recommended dose from manufacturer and the actual dose applied to each of hospitals. injection of inappropriate $^{18}F$-FDG dose may not only increase the exposed dose to patients but also reduce the image quality. we thus evaluated the proper $^{18}F$-FDG injected dose to decrease the exposed dose to patients considering the image quality. Materials And Methods: NEMA Nu2-1994 phantom was filled with $^{18}F$-FDG increasing hot cylinder radioactivity concentration to 1, 3, 5, 7, 9 MBq/kg based on the ratio of 4:1 between the hot cylinder and background activity. after completing the transmission scan using ct, emission scan was acquired in 3D mode for 2 minutes 30 seconds/bed. ROI was set up on hot cylinder and background radioactivity region. after measuring $SUV_{max}$ those regions, then analyzed SNR at the points. clinical experiment has been conducted the object of patients who have came to smc from november 2009 to august 2010, 97 patients without having a hepatic lesions were selected. ROI was set up in the liver and thigh area. after measuring $SUV_{max}$, the image quality was compared following the injected dose. Results: in phantom study, as the injected radioactivity concentration per unit mass was 1, 3, 5, 7, 9 MBq/kg, $SUV_{max}$ was 23.1, 24.1, 24.3, 22.8, 23.6 and SNR was shown 0.48, 0.54, 0.56, 0.55, 0.55. according to increment of the injected dose, $SUV_{max}$ and SNR was increased under 5 MBq/kg but they were decreased over 7 MBq/kg. in case of clinical experiment, as increased the injected radioactivity concentration per unit mass was 4.72, 5.34, 6.16, 7.41, 8.68 MBq/kg, $SUV_{max}$ was 2.68, 2.67, 2.26, 1.88, 1.95 and SNR was shown 0.52, 0.53, 0.46, 0.46, 0.44. if the injected dose exceeds 5 MBq/kg, showed a decrease pattern as phantom study. Conclusion: increasing $^{18}F$-FDG injected dose considered patient's body weight improve image quality within a certain range. if it exceeds the range, it can be reduced image quality due to random and scatter coincidences. this study indicates that the optimal injected dose was 5 MBq/kg per unit mass the injected radioactivity concentration in 3d wb pet/ct.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.2
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• pp.3-7
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• 2014

Purpose SPECT/CT scan to be performed attenuation correction on the basis of CT induce an overestimation of the site due to the beam hardening artifact by metal cover and reduce the images quality. Therefore, this study using a phantom that has been inserted artificial hip joint investigated that effect on the SPECT/CT image causing by metal artifact for varying the parameters of the Attenuation Map. Materials and Methods Siemens Symbia T16 SPECT/CT equipment was used. Artificial hip joint was inserted to SPECT/PET phantom, 17 mm sphere of Bright Streak area in CT image was filled with Tc-99m so that the radiation activity was 8 times compared to background. And then Hot and Background was measured in varying Wide Beam Coefficient on Attenuation Map and RBR (Region to Background Ratio) of Metal and Non-Metal was calculated and analyzed depending on the presence or absence of the hip joint. Results It tended to hot count of Non-Metal and Metal to increase as the value of the manual mode is increased, hot count ratio with the group of both manual mode 0.5 and 0.4 is the best match. Also, in automatic mode, the ratio of RBRNon-Metal and RBRMetal was 1.135, statistically significant difference was not observed in the manual mode 0.5 and 0.4. Conclusion In the automatic mode of Wide Beam Coefficient in attenuation correction map, it was found that it is over-correction by 13.52%, it was possible to minimize the over-correction by the artifact in 0.5 and 0.4 of manual mode. Further studies should be performed in order to apply to a patient with the help of this and it is considered possible to reduce the over-correction by the metal artifact of an artificial hip joint for Hip-Resurfacing Arthroplasty patients, and to improve the diagnostic performance.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.70-74
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• 2011

Purpose: In the Nuclear Medicine department of Asan Medical Center, radioactive waste has been disposed of by using several disposal boxes designed for nuclear waste. However, some quantity of radioactivity has been detected occasionally due to some radiologists' carelessness not only from radioactive waste, but also from medical waste such as uncontrolled radioactive waste related to patients, poly gloves or saline solution bottles from radiopharmaceuticals laboratory. Thus, this study is going to suggest a solution to maintain the medical wastes made from controlled areas that can be below maximum permissible surface dose limits by finding the cause of radioactive contamination. Materials and methods: This study was taken place in 17 different places-2 medical wastebaskets in the waiting room, 2 medical wastebaskets in the PET room, 5 medical wastebaskets in the in vitro laboratory and 6 medical wastebaskets in the radiopharmaceuticals laboratory of the East building, 2 medical wastebaskets in the waiting room of the New building of Nuclear Medicine Department in Asan Medical Center from April to August 2010. Mean radioactivity and its standard deviation of each place have been found by measuring surface contamination of medical wastebaskets and backgrounds twice a week, totaling 30 times. An independent t-test of SPSS (Ver. 12.0) statistic program has been used for statistical analysis. Swabs, saline solution bottles and poly gloves collected from each place also measured 30 times, respectively. Results: This study analyzed medical waste and the backgrounds of each place by using survey meter detectors that significant differences of five places did not exist, but existed statistically in twelve places (p<0.05). Also, swabs, saline solution bottles and poly gloves collected from each radioactive waste partly exceed the legal dose limit as a result of measuring by a gamma counter. Conclusion: Backgrounds and the surface doses of radioactive disposal box in all 17 places measured by the survey meter did not exceed the legal dose limit; however, it obviously showed that there were prominent differences in 12 places. Assuming that the cause of the differences was swabs, saline solution bottles and gloves, we examined them by gamma counter, and the results showed remarkably high doses of radioactivity. Consequently, swabs and poly gloves which are normally disposed in the general medical waste box should be disposed in the radioactive waste box furnished by radiopharmaceuticals laboratory. Also, saline solution discharged from radioactive pharmaceutical places is considered as radioactive liquid waste so that it should be disposed of by the septic tank specifically designed for radioactive liquid.

• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.481-488
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• 2005

Purpose: Functional imaging of dopamine transporter (DAT) defines integrity of the dopaminergic system, and DAT is the target site of drugs of abuse such as cocaine and methamphetamine. Functional imaging the DAT may be a sensitive and selective indicator of neurotoxic change by the drug. The aim of the present study is to evaluate the clinical implications of qualitative/quantitative analyses of dopamine transporter imaging in methamphetamine abusers. Materials and Methods: Six detoxified methamphetamine abusers (abuser group) and 4 volunteers (control group) were enrolled in this study. Brain MRI was performed in all of abuser group. Abuser group underwent psychiatric and depression assessment using brief psychiatric rating scale (BPRS) and Hamilton depression rating scale (HAMD), respectively. All of the subjects underwent I-123 IPT SPECT (IPT SPECT). IPT SPECT image was analysed with visual qualitative method and quantitative method using basal ganglia dopamine transporter (DAT) specific/non-specific binding ratio (SBR). Comparison of DAT SBR between abuser and control groups was performed. We also performed correlation tests between psychiatric and depression assessment results and DAT SBR in abuser group. Results: All of abuser group showed normal MRI finding, but had residual psychiatric and depressive symptoms, and psychiatric and depressive symptom scores were exactly correlated (r=1.0, p=0.005) each other. Five of them showed abnormal finding on qualitative visual I-123 IPT SPECT Abuser group had lower basal ganglia DAT SBR than that of control ($2.38{\pm}0.20\;vs\;3.04{\pm}0.27$, p=0.000). Psychiatric and depressive symptoms were negatively well correlated with basal ganglia DAT SBR (r=-0.908, p=0.012, r=-0.924, p=0.009). Conclusion: These results suggest that dopamine transporter imaging using I-123 IPT SPECT may be used to evaluate dopaminergic system of the basal ganglia and the clinical status in methamphetamine abusers.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.3
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• pp.229-234
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• 2008

Hepatobiliary scintigraphy is very sensitivity of hepatic cell and gallbladder, biliary track atresia and biliary leakage. however, Hepatobiliary scan of biliary leakage diagnosis was separated determine biliary leakage and bowl drainage bile-juice. The object of this study will determine biliary leakage and bowl drainage bile-juice to hepatobiliary scintigraphy both decubitus position in bile leakage patients. Material & Methode: 31 patients (meal 14, Femeal 17), $51.1{\pm}14.4$ years. dynamic scan acquisition 60 farme for 60 minute on supine position. and delay scan was 2 hrs, 4 hrs, 24 hrs for 5 minute on supine, both decubitus position. Both decubitus position scan was kept for 5 minutes. Efficient of Hepatobiliary Scintigraphy both decubitus position in bile leakage patients was compared leakage size, density, image of supine position and both decubitus position. Results: 23 patients for 31 bile leakage patients was checked up function image or delay image, and 8 patients was checked up bile leakage on both decubitus. anatomical leakage location was supine position very well, but both decubitus position was separated bile leakage and moving bile-juice in bowl. also, uptake (counts/pixel) average of roi and bkg was supine 5.02, left decubitus 2.08, right decubitus 2.68. No. pixels of supine ROI counted 1.91 times than left decubitus, 1.05 times than right decubitus. Conclusion: 31 patient both decubitus position, but decubitus position was separated bile juice movement in bowl leakage location. also, It was compared ROI/BKG ratio and ROI No. pixels of supine, both decubitus in 38.5% patients. And No. pixels of supine position was large 19%, 5% than left decubitus, right decubitus, And density was in low 60%, 50% than left decubitus, right decubitus. It was mean bile leakage of ROI. so, If Hepatobiliary Scintigraphy was additional both decubitus position scan in bile leakage patients, this study will be more valuable in diagnosis of bile leakage.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.433-440
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• 2018

Recently, MTV(metabolic tumor volume) has been used as indices of the whole tumor FDG uptake on FDG PET image but it is influenced by image reconstruction. The purpose of this study was to evaluate the correlation between actual volume and metabolic tumor volume applying different SUVmax threshold for different reconstruction algorithm on phantom study. Measurement were performed on a Siemens Biograph mCT40 using a NEMA IEC body phantom containing different size six spheres filled with F18-FDG applying four SBRs (4:1, 8:1, 10:1, 20:1). Images reconstructed four algorithms (OSEM3D, OSEM3D+PSF, OSEM3D +TOF, OSEM3D+TOF+PSF) and MTV were measured with different SUVmax threshold. Overall, the use of increasing thresholds result in decreasing MTV. and increasing the signal to background ratio decreased MTV by applying same SUVmax threshold. The 40% SUVmax threshold gave the best concordance between measured and actual volume in PSF and PSF+TOF reconstruction image. and the 45% threshold had the best correlation between the volume measured and actual volume in OSEM3D and TOF reconstruction image. we believe that this study will be used when the measurement of MTV applying various reconstruction image.