• Progress in Medical Physics
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• v.17 no.3
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• pp.173-178
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• 2006

The purpose of this study was to evaluate the radiation dose for clinical PET/CT protocols in clinical environments using Alderson phantom and TLDs. Radiation doses were evaluated for both Philips GEMINI 16 slice PET/CT system and GE DSTe 16 slice PET/CT system. Specific organ doses with $^{137}Cs$ transmission scan, high quality CT scan and topogram in philips GEMINI PET/CT system were measured. Specific organ doses with CT scan for attenuation map, CT scan for diagnosis and topogram in GE DSTe PET/CT system were also measured. The organs were selected based on ICRP60 recommendation. The TLDs used for measurements were selected for within an accuracy of ${\pm}5%$ and calibrated in 10 MV X-ray radiation field. The effective doses for $^{137}Cs$ transmission scan, high qualify scan, and topogram in Philips GEMINI PET/CT system were $0.14{\pm}0.950,\;29.49{\pm}1.508\;and\;0.72{\pm}0.032mSv$ respectively. The effective doses for CT scan to make attenuation map, CT scan to diagnose and topogram in GE DSTe PET/CT system were $20.06{\pm}1.003,\;24.83{\pm}0.805\;and\;0.27{\pm}0.008mSv$ respectively. We evaluated the total effective dose by adding effective dose for PET Image. The total PET/CT doses for Philips GEMINI PET/CT (Topogram+$^{137}Cs$ transmission scan+PET, Topogram+high qualify CT+PET) and GE DSTe PET/CT (Topogram +CT for attenuation map+ PET, Topogram+diagnostic CT+ PET) are $7.65{\pm}0.951,\;37.00{\pm}1.508,\;27.12{\pm}1.003\;and\;31.89{\pm}0.805mSv$ respectively. Further study may be needed to be peformed to find optimal PET/CT acquisition protocols for reducing the patient exposure with good image qualify.

• Progress in Medical Physics
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• v.24 no.1
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• pp.68-75
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• 2013

The purpose of this research is to compare and analyze $SUV_{LBM}$-maximum of normal regions using VOI (the volume of interest) in order to enhance the diagnostic level in whole body images of PET/CT and PET/MRI for 26 health check-up participants. In particular, we try to set up $SUV_{LBM}$-maximum data that can be used in synchronous evaluation for PET/CT and PET/MRI without contrast media. The evaluation of $SUV_{LBM}$-maximum for normal regions of whole body PET/CT and whole body PET/MRI shows that the image of PET/MRI differs very significantly from the reference image of PET/CT (p<0.0001). However, they exhibit high correlations in view of statistics (R>0.8). From this research, we suggest that the decision in the evaluation of $SUV_{LBM}$-maximum for PET/MRI should be made with the reduction of about 26.3%, while one should decide with the reduction of about 29.3% when the contrast media is used. It is helpful to interpret all image of PET/CT and PET/MRI using $SUV_{LBM}$-maximum for convenience and efficiency.

• Progress in Medical Physics
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• v.17 no.4
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• pp.246-251
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• 2006

The purpose of this study was to evaluate SUV (standard uptake value) using different reconstruction methods in whole body PET/CT Imaging. PET/CT studies were peformed with and without correction for effect of contrast media. The patients data were acquired using GE DSTe commercial PET/CT system. The liver disease (hepatocellular carcinoma, HCC) and renal disease (renal ceil carcinoma, RCC) patients were selected for this study, The PET/CT data were reconstructed using post CT scan with and without correction for effect of contrast media. We selected ROIs (region of Interest) at the same location and same area for the same patient to compare SUVs in these two methods. For HCC and RCC, the average differences of SUVs were measured as $1.5{\pm}1.2%\;and\;1.0{\pm}0.9%$, respectively. For HCC and RCC, the maximum differences of SUVs were measured as 4.3% and 1.9%, respectively. We observed that SUVs without correction for effect of contrast media were higher than SUVs with correction for effect of contrast media. However the differences of SUVs were very minimal. These results may be limited to HCC and RCC and further studies will be Heeded for other organs or diseases to see any changes in SUV with and without correction for effect of contrast media.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.44-49
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• 2012

Purpose: In the whole body PET/CT scan, it is natural to lift the patient's arm for its quality improvement. However, when the lesion is located in head and neck, the arms should be located lower. This study was designed to compare the CT effective dose for each arm position applying Automatic Exposure Control (AEC). Materials and Methods: 45 patients who had $^{18}F$-FDG whole body PET/CT scan were studied with Biograph Truepoint 40 (SIEMENS, GERMANY), Biograph Sensation 16 (SIEMENS, GERMANY), Discovery STe 8 (GE healthcare, USA). The CT effective dose of 15 patients for each equipment was measured and comparatively analyzed in both arm-lifted position and lower-arm position. ImPACT v1.0 program was used as the method of measurement for CT effective dose. For the statistics analysis, Paired t-test which paired with SPSS 18.0 statistic program was applied. Results: In the case of arm-lifted, it was measured as $6.33{\pm}0.93mSv$ for Biograph Sensation 16, $8.01{\pm}1.34mSv$ for Biograph Truepoint 40, and $9.69{\pm}2.32mSv$ for Discovery STe 8. When arms are located lower position, it was measure as $6.97{\pm}0.76mSv$, $8.95{\pm}1.85mSv$, $13.07{\pm}2.87mSv$ for each. CT effective dose according to the arm position was 9.2% for Biograph Truepoint 40, 10.5% for Biograph Sensation 16, and 25.9% for Discovery Ste 8. The statistics analysis showed the meaningful difference ($p$<0.05). Conclusion: For the whole body PET/CT case, CT effective dose applying AEC was decreased the radiation exposure of the patients when the arm was lifted for 15.2% of average value. The patient who has no lesion in head and neck would decrease the artifact occurrence in objective part and lower the CT effective dose. Also, for the patient who had lesion in head and neck, the artifact in objective part can be lower by putting the arms down, the fact that CT effective dose increases should be concerned in its whole body PET/CT scan.

• Progress in Medical Physics
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• v.24 no.3
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• pp.176-182
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• 2013

Through this research, we measure the data for several SUVs such as SUVLBM, SUVBW, and SUVBSA using volume of interest in order to enhance the diagnostic level in whole-body image for healthy examinees via F-18 FDG PET/CT. Maximum value, mean value, standard deviation, and threshold value for each SUVs are shown. The measurement of SUVs are carried out with 31 examinees who have taken whole-body examination with F-18 FDG PET/CT from July, 2012 to August, 2012. To secure the preciseness of measurement, we selected 26 healthy examinees as a subject of measurement according to diagnostic view of a nuclear-medical doctor. We see from the measurement of SUVs of PET/CT that the value of SUVBW is hightest and followed by SUVLBM and SUVBSA in turn regardless of the use of contrast media. By comparing the SUVLBM-maximum data for the group used contrast media with those for the group used no contrast media, there found a trend that the measured values increase when the contrast media are used. Among them, liver, aorta, lumbar-5, and Cerebellum exhibit significant difference (p<0.05). We conclude that our data for SUVs would be basic references in overall image interpretation, and hope that the research using VOI would be active.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.39-43
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• 2008

Purpose: We evaluated whether it was necessary to perform whole body acquisition of $^{18}F$-FDG PET/CT including whole skull and lower extremity (LE) distal to mid-thigh (MT) in patients with multiple myeloma (MM). Materials and Methods: Thirty patients underwent 45 whole body $^{18}F$-FDG PET/CT scans including skull and LE distal to MT. PET scans were divided by 2 subgroups according to the presence of abnormal focal $^{18}F$-FDG uptake in skull or LE distal to MT. Clinical characteristics including age, sex, and stages were compared between the 2 subgroups. Results: Of total 45 whole body PET/CT scans, focally increased abnormal FDG uptake in the skull or LE distal to MT suggesting myeloma involvement was found in 22 scans (48.9%) of 14 patients (46.7%). Skull lesions were more frequently observed than LE lesions distal to MT on PET (86.4% vs. 40.9%, p<0.005). There were no significant differences in age, sex, initial Durie/Salmon stage, and tumor burden at the time of PET scan suggested by serum hemoglobin level, serum calcium level, serum and urine paraprotein level, and serum creatinine level between the two subgroups. The presence of the skull or LE distal MT lesions on PET did not affect on the Durie/Salmon plus stage except only 1 case (1/22, 4.5%, p>0.05). Conclusion: Abnormal lesions in the skull or LE distal to MT on $^{18}F$-FDG PET/CT did not affect significantly on the tumor burden and Durie/Salmon plus stage of MM. Therefore, torso PET acquisition including head may be sufficient for evaluating patients with MM.

• Progress in Medical Physics
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• v.17 no.2
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• pp.89-95
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• 2006

The purpose of this study was to evaluate the radiation doses during CT transmission scan by changing tube voltage and tube current, and to estimate the radiation dose during our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan. Radiation doses were evaluated for Philips GEMINI 16 slices PET/CT system. Radiation dose was measured with standard CTDI head and body phantoms in a variety of CT tube voltage and tube current. A pencil ionization chamber with an active length of 100 mm and electrometer were used for radiation dose measurement. The measurement is carried out at the free-in-air, at the center, and at the periphery. The averaged absorbed dose was calculated by the weighted CTDI ($CTDI_w=1/3CTDI_{100,c}+2/3CTDI_{100,p}$) and then equivalent dose were calculated with $CTDI_w$. Specific organ dose was measured with our clinical whole body $^{137}Cs$ transmission scan and high quality CT scan using Alderson phantom and TLDs. The TLDs used for measurements were selected for an accuracy of ${\pm}5%$ and calibrated in 10 MeV X-ray radiation field. The organ or tissue was selected by the recommendations of ICRP 60. The radiation dose during CT scan is affected by the tube voltage and the tube current. The effective dose for $^{137}Cs$ transmission scan and high qualify CT scan are 0.14 mSv and 29.49 mSv, respectively. Radiation dose during transmission scan in the PET/CT system can measure using CTDI phantom with ionization chamber and anthropomorphic phantom with TLDs. further study need to be peformed to find optimal PET/CT acquisition protocols for reducing the patient exposure with same image qualify.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.257-260
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• 2006

In order to evaluate the exposure to the radiologic technologists from patients who had been administrated with radiopharmaceuticals, we measured the spatial dose rates at $5{\sim}300\;cm$ from skin surface of patients using an proportional digital surveymeter, 1.5(PET scan) and 4hr(bone scan) after injection. In results, the exposure to the technologists in each procedure was small, compared with the dose limits of the medical workers. However, the dose-response relationships in cancer and hereditary effects, referred to as the stochastic effects, have been assumed linear and no threshold models ; therefore, the exposure should be minimized. For this purpose, the measurements of spatial dose rate distributions were thought to be useful.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.185-193
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• 2007

This review focuses on the use of $^{18}F-FDG$ PET/CT to evaluate second primary cancers. The emergence of a second primary cancer is an important prognostic factor in cancer patients. The early detection of a second primary cancer and the appropriate treatment are essential for reducing the morbidity and mortality associated with these tumors. Integrated $^{18}F-FDG$ PET/CT, which can provide both the metabolic and anatomic information of a cancer, has been shown to have a better accuracy in oncology than either CT or conventional PET. The whole body coverage and high sensitivity of $^{18}F-FDG$ PET/CT along with its ability to provide both metabolic and anatomic information of a cancer make it suitable for evaluating a second primary cancer in oncology. Whole body $^{18}F-FDG$ PET/CT is useful for screening second primary cancers with a high sensitivity and good positive predictive value. In order to rule out the presence of a second primary cancer or an unexpected metastasis, further diagnostic work-up is essential when abnormal findings indicative of a second primary cancer are found on the PET/CT images. PET/CT is better in detecting a second primary tumor than conventional PET.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.2
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• pp.83-87
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• 2008

Diagnostic and functional imaging device have been developed independently. The recognition that combining of these two devices can provide better diagnostic outcomes by fusing anatomical and functional images. The representative examples of combining devices would be PET/CT and SPECT/CT. Development and their applications of animal imaging and instrumentation have been very active, as new drug development with advanced imaging device has been increased. The development of advanced imaging device resulted in researching and developing for detector technology and imaging systems. It also contributed to develop a new software, reconstruction algorithm, correction methods for physical factors, image quantitation, computer simulation, kinetic modeling, dosimetry, and correction for motion artifacts. Recently, development of MRI and PET by combining them together was reported. True integration of MRI and PET has been making the progress and their results were reported. The recent status of imaging and instrumentation in nuclear medicine is reported in this paper.