• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.356-363
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• 2014

Recently pediatric CT has been performed by reduced dose according to tube current modulation이라고, this fact has a possibility more reduce a dose because of strong affect depend on tube current modulation. Almost all MDCT snow show and allow storage of the volume CT dose index (CTDIvol), dose length product (DLP), and effective dose estimations on dose reports, which are essential to assess patient radiation exposure and risks. To decrease these radiation exposure risks, the principles of justification and optimization should be followed. justification means that the examination must be medically indicated and useful. Results is using tube current modulation이라고 tend to the lower kV, the lower effective dose. In case of use a low dose CT protocol, we found a relatively lower effective dose than using tube current modulation. Average effective dose of our studies(brain, chest, abdomen-pelvis) less than 47%, 13.8%, 25.7% of germany reference dose, and 55.7%, 10.2%, 43.6% of UK(United Kingdom) reference dose respectively. when performed examination for reduced dose, we must use tube current modulation and low dose CT protocol including body-weight based tube current adaption.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.63-69
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• 2013

Comparing with film-screen system, flat-panel detector has extensive dynamic range. Focusing flat-panel detector, whole body human phantom PBU-50 (Kyoto, kagaku, Japan) was used to perform comparative study of the estimate of image quality and exposure dose. the exposure condition was 81kV and 20mAs, which is used for Abdomen supine exam in clinical area. As a result of the kV change of the interpreted medical image which has over 30dB of PSNR value, the value of DAP shows the difference of 19.6 times. Moreover, the result of comparing kV change with effective dose of ICRP 103 shows that stochastic effect was increased by over exposure. Therefore, it is significantly necessary that digital radiation technical chart will be used to obtain high quality image and make the standard of dose by educating radio-technologist continually.

• Journal of radiological science and technology
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• v.34 no.1
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• pp.27-33
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• 2011

Along with the developments of science technology, up-to-date medical radiation equipments are introduced. Those equipments has brought many progresses in diagnosing patients not only in the quantitative aspects but in the qualitative ones. Especially, in the case of dental radiography, patients can be exposed more than CT, cone beam computed tomography (CBCT). In this study, we used human phantom and TLD-100H to measure the organ dose in each dental radiography and computed the effective dose according to ICRP (International Committee for Radioactivity Prevention) 60, 103. We measured the effective dose to be 5.1 and $29.5{\mu}Sv$ in the panoramic radiography and 11.2 and $14.4{\mu}Sv$ in the cephalometric radiography respectively. We also executed the CBCT and CT test on the maxillaries and the mandibles and found the amounts of effective dose were 53.7, 209.6, 129, and $391.5{\mu}Sv$ respectively in the CBCT and $93.3{\mu}$, 139.5, 282.7 and $489.7{\mu}Sv$ in the CT test. Consequently, it was shown that the effective dose in the CBCT test was lower than one in the CT test, but was higher in both panoramic and cephalometric radiography.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.199-204
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• 2001

Purpoe : To find the optimal values of total arc degree to protect the normal brain tissue from high dose radiation in stereotactic radiotherapy planning. Methods and Materials : With Xknife-3 planning system & 4 MV linear accelerator, the authors planned under various values of parameters. One isocenter, 12, 20, 30, 40, 50, and 60 mm of collimator diameters, $100^{\circ},\;200^{\circ},\;300^{\circ},\;400^{\circ}C,\;500^{\circ},\;600^{\circ}$ or total arc degrees, and $30^{\circ}\;or\;45^{\circ}$ or arc intervals were used. After the completion of planning, the plans were compared each other using $V_{50}$ (the volume of normal brain that is delivered high dose radiation) and integral biologically effective dose. Results : At $30^{\circ}$ of arc interval, the values of $V_{50}$ had the decreased pattern with the increase of total arc degree in any collimator diameter. At 45 arc interval, up to $400^{\circ}$ of total arc degree, the values of $ V_{50}$ decreased with the increase of total arc degree, but at $500^{\circ}\;and\;600^{\circ}$ of total arc degrees, the values increased. At $30^{\circ}$ of arc interval, integral biologically effective dose showed the decreased pattern with the increase of total arc degree in any collimator diameter. At $45^{\circ}$ arc interval with less than 40 mm collimator diameter, the integral biologically effective dose decreased with the increase of total arc degree, but with n and n mm or collimator diameters, up to $400^{\circ}$ or total arc degree, integral biologically effective dose decreased with the increase of total arc degree, but at $500^{\circ}\;and\;600^{\circ}$ of total arc degrees, the values increased. Conclusion : In the stereotactic radiotherapy planning for brain lesions, planning with $400^{\circ}$ of total arc degree is optimal. Especially, when the larger collimator more than 50 mm diameter should be used, the uses of $500^{\circ}\;and\;600^{\circ}$ of total arc degrees make the increase of$V_{50}$ and integral biologically effective dose. Therefore stereotactic radiotherapy planning using $400^{\circ}$ of total arc degree can increase the therapeutic ratio and produce the effective outcome in the management of personal and mechanical sources in radiotherapy department.

• Journal of Radiation Protection and Research
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• v.39 no.1
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• pp.30-37
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• 2014

Recently High-Definition Reference Korean-Man (HDRK-Man) and High-Definition Reference Korean-Woman (HDRK-Woman) were constructed in Korea. The HDRK phantoms were designed to represent respectively reference Korean male and female to calculate effective doses for Korean by performing Monte Carlo dose calculation. However, the Monte Carlo dose calculation requires detailed knowledge on computational human phantoms and Monte Carlo simulation technique which regular researchers in radiation protection dosimetry and practicing health physicists do not have. Recently the UFPE (Federal University of Pernambuco) research group has developed, and opened to public, an online Monte Carlo dose calculation system called CALDOSE_X(www.caldose.org). By using the CALDOSE_X, one can easily perform Monte Carlo dose calculations. However, the CALDOSE_X used caucasian phantoms to calculate organ doses or effective doses which are limited for Korean. The present study developed an online reference Korean dose calculation system which can be used to calculate effective doses for Korean.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.181-186
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• 2016

Cardiac angiography(CA) or cardiac intervention(CI) is one of the major examination methods applied to the detection of cardiovascular diseases using X-rays. These CA and CI procedures require radiation exposure to patients and physicians. We evaluated the radiation dose to cardiac operator during the each case of CA and CI procedures. The number of patients is 113 patients in CA and 34 patients in CI. Mean fluoroscopy time, mean cine time, and mean total cumulative dose area product(DAP) in patients during CA and CI was 165.9 sec vs. 1200.0 sec, 30.31 sec vs 107.5 sec, and $37130.3mGy.cm^2$ vs $213312.6mGy.cm^2$, respectively. Mean dose of thyroid, over chest apron and under chest apron in operator during CA and CI was 15.84 uSv vs 89.81 uSv, 20.16 uSv vs 123.20 uSv, and 0.30 uSv vs 2.40 uSv, respectively. Mean effective dose of operator during CI was about 6 times greater than during CA. Also there was significant inter-relationship between fluoroscopy or cine time and effective dose in operator during CA and CI(p=0.001 and p=0.001, respectively).

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1041-1047
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• 2021

In this study, the effective dose for frequently general radiography among the diagnostic reference level (DRL) for examinations provided by the government in Korea was evaluated using the Monte Carlo N-Particle eXtended (MCNPX) simulation tool. We were selected to evaluate for a total of 5 examination sites which included head anterior-posterior, chest (posterior-anterior, lateral), abdomen anterior-posterior and pelvis anterior-posterior. Physical conditions such as tube voltage and tube current used in MCNPX simulation were used in domestic conditions of the Korea Disease Control and Prevention Agency (KDCA). To evaluate domestic medical radiation exposure, we used the HDRK-Man computerized human phantom manufactured based on the international standard ICRP 103 that was applied to the MCNPX simulation. The phantom could represent the standard body shape of Koreans. As a results, the effective dose corresponding to the DRL based on adult males of head anterior-posterior position was 0.086 mSv, chest posterior-anterior position was 0.05 mSv, chest lateral was 0.354 mSv, abdomen anterior-posterior position was 0.548 mSv, and pelvis anterior-posterior position was 0.451 mSv.

• Progress in Medical Physics
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• v.26 no.4
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• pp.267-272
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• 2015

In this study, the reduction of dose and risk was evaluated from using automatic mA control in 4D CT scan of patients whose organ movement was considered for gated radiotherapy. The organ doses, CTDI, effective doses from 4D CT with and without using automatic mA control were evaluated using CT-Expo program for each 10 patients of liver and lung cancer, and the risk of exposure induced death and loss of life expectancy were evaluated using PCXMC program. It was founded that there were 26.8%, and 15.5% dose reduction in organ doses and CTDI for liver and lung cancer patients and 16.5% and 19.8% risk reduction in liver and lung cancer patients. The organ doses and effective doses were evaluated for the parameter of each patient used in CT scans, and risks considering age and gender could be evaluated. It was founded that there were 21.2% dose reduction and 18.2% risk reduction in 4D CT scan using AEC for liver and lung cancer patients.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.1-10
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• 2010

Dental panoramic radiography is an imaging technique which shows the information of teeth, jaws and superficial structures on a single image. In this study, we propose the clinical dose reference for dental panoramic radiography. Dental panoramic radiography is an application which can increase the radiation does of oral cavity. It is very important to study the real condition of management for these panoramic X-ray equipments. Since there was no researches on dental panoramic equipments in domestic and foreign study groups, we measured and analyzed the dose such as effective dose, DAP and DWP of panoramic radiography.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.473-479
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• 2023

In this study, the dose of photoneutrons generated during radiotherapy of prostate cancer using high energy was measured using a photo-stimulated luminescence dosimeter. In addition, this study was intended to study the probability of side effects occurring in the abdomen. A medical linear accelerator capable of generating 15 MV energy, True Beam STx (Varian Medical Systems, USA) and a radiation treatment planning system (Eclipse, Varian Medical Systems, USA) were used. A human body phantom was installed on the couch of the linear accelerator, and an Albedo Neutron Optical Stimulation Luminescence Neutron Detector (Landauer Inc., IL, USA) was used to measure the photoneutron dose. The photoneutron dose value in the abdomen of VMAT and 3C-CRT was 52.8 mSv, more than twice as high as VMAT compared to 3D-CRT. During radiotherapy of prostate cancer, the probability of causing side effects in the abdomen due to light neutron dose was calculated to be 3.2 per 1,000 for VMAT and 1.4 for 3D-CRT. By studying the abdomen, which has a major side effect that can occur during radiotherapy of prostate cancer, it is expected that it will be used as a meaningful study to study the quality of life and stochastic effect of prostate cancer patients