방사선촬영에서 면적선량 및 새로운 실질면적선량 개념의 비교 평가

최우철(Woo Cheol Choi),김용민(Yongmin Kim),김정수(Jung Su Kim) 대한방사선과학회(구 대한방사선기술학회) 2021 방사선기술과학 Vol.44 No.1

Kerma Area Product (KAP) is best indicator of radiation monitoring on radiographic examinations. KAP can be measured differently depending on the X-ray irradiation area, air kerma, souce-skin distance, type of equipment, etc. The major factors are exposure area and the air krema. The KAP currently used only considers the exposure area with X-rays and has a problem that KAP is always excessively overestimated from the dose received by an actual subject. Therefore, in this study, in order to measure the accurate KAP, a new area dose calculation that can be calculated by dividing the area where the actual X-ray is irradiated is presented, and the KAP is the real area. We compared and analyzed how much it was overestimated compared to the dose. The Skull AP projection and seven other projection were compared and analyzed, and the KAP was overestimated in each test by 52% to 60%. In this way, the effective KAP (EKAP) calculation developed through this study should be utilized to prevent extra calculation of the existing KAP, and only the accurate patient subject area should be calculated to derive the accurate area dose value. EKAP is helpful for control the patient s exposure dose more finely, and it is useful for the quality control of medical radiation exposure.

복사전달과정에서 지형효과에 따른 기상수치모델의 민감도 분석

지준범,민재식,장민,김부요,조일성,이규태 한국기상학회 2017 대기 Vol.27 No.4

Numerical weather prediction experiments were carried out by applying topographic effects to reduce or enhance the solar radiation by terrain. In this study, χ and κ(φo, θo) are precalculated for topographic effect on high resolution numerical weather prediction (NWP) with 1 km spatial resolution, and meteorological variables are analyzed through the numerical experiments. For the numerical simulations, cases were selected in winter (CASE 1) and summer (CASE 2). In the CASE 2, topographic effect was observed on the southward surface to enhance the solar energy reaching the surface, and enhance surface temperature and temperature at 2 m. Especially, the surface temperature is changed sensitively due to the change of the solar energy on the surface, but the change of the precipitation is difficult to match of topographic effect. As a result of the verification using Korea Meteorological Administration (KMA) Automated Weather System (AWS) data on Seoul metropolitan area, the topographic effect is very weak in the winter case. In the CASE 1, the improvement of accuracy was numerically confirmed by decreasing the bias and RMSE (Root mean square error) of temperature at 2 m, wind speed at 10 m and relative humidity. However, the accuracy of rainfall prediction (Threat score (TS), BIAS, equitable threat score (ETS)) with topographic effect is decreased compared to without topographic effect. It is analyzed that the topographic effect improves the solar radiation on surface and affect the enhancements of surface temperature, 2 meter temperature, wind speed, and PBL height.

핵의학과 PET/CT실 방사선작업종사자의 수정체 부위의 등가선량과 흉부의 유효선량의 측정 비교

손상준(Son Sang-Joon),박정규(Park Jeong-Kyu),정동경(Jung Dong-Kyung),박명환(Park Myeong-Hwan) 대한방사선과학회(구 대한방사선기술학회) 2019 방사선기술과학 Vol.42 No.3

Comparison of the effective dose of the chest and the equivalent dose of the lens site in the radiation workers working at four medical institutions with the PET / CT room located in one metropolitan city and province from April 1 to June 30, 2018 Respectively. Radioactive medicine were measured at the time of dispensing and at the time of injection. In this experiment, the average dispensing time per patient was 5.7 minutes and the average injection time was 3.1 minutes. The equivalent dose at the lens site was 0.78 μSv/h for 1 mCi, and the effective dose for chest was 0.18 μ Sv/h per 1 mCi. The equivalent dose at the lens site during injection was 0.88 μSv/h per mCi and the effective dose of chest was 0.20 μSv/h per mCi. The daily effective dose of the chest was 0.9±0.6 μSv and the equivalent dose of the lens site was 3.6±1.4 μSv during daily dosing for 20 days. The effective dose of the chest during the day was 0.6±0.5 μSv and the equivalent dose of the lens was 2.2±1.0 μSv. At the time of dispensing, the equivalent dose of the lens was 0.187±0.035 mSv, the effective dose of the chest was 0.137±0.055 mSv, the equivalent dose of the lens was 0.247±0.057 mSv, and the effective dose of the monthly chest was 0.187±0.021 mSv. As a result of the corresponding sample test, the equivalent dose and the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, the effective dose of the chest, The equivalent dose of the lens and the effective dose of the chest were statistically significant (p<0.05) with a significance of 0.000. However, there was no statistically significant difference (p>0.05) between the equivalent dose and the effective dose of the chest, the equivalent dose of the lens at the time of injection, and the effective dose of the chest at 0.138 and 0.230, respectively.

5MHz 초과 초음파자극기에 대한 IEC 61689 규격 적용의 유효성에 관한 연구

윤주신,최기상,Youn, Ju-Shin,Choi, Gi Sang 대한의용생체공학회 2015 의공학회지 Vol.36 No.3

Ultrasonic physiotherapy systems should comply with IEC 60601-2-5(particular requirements for safety of ultrasonic physiotherapy equipment) standard for safety of patients and clinical performances. One of the most important parameters in the standard is the effective radiating area ($A_{ER}$). It has to be measured in accordance with IEC 61689 (field specifications and methods of measurement in the frequency range 0.5MHz to 5MHz). Typical ultrasonic physiotherapy system works in the frequency range 1MHz ~ 3MHz to comply with the IEC 61689. However, ultrasonic physiotherapy system using frequencies over 5MHz is out of the IEC 61689's scope. That is, even if such ultrasonic physiotherapy systems are developed by demands of the market, there is no standard to apply. It is the motivation for this study. Whereas there are other parameters to be considered, this study focuses on the effective radiating area and shows effectiveness of applying IEC 61689 in measuring effective radiating area of ultrasonic physiotherapy systems using frequency range over 5MHz by comparing the results of computer simulation and experiment. Results of this study shows that applying the IEC 61689 standard to ultrasonic physiotherapy system using frequency range over 5MHz is possible.

ERCP 검사 시 방사선 피폭량과 암 위험도 분석

이양섭,서대건,조재환 (사)한국방사선산업학회 2018 방사선산업학회지 Vol.12 No.3

Therapeutic endoscopic retrograde cholangiopancreatography (ERCP) requiresfluoroscopic and radiographic exposures, which impose radiation risks to patients. The aim of thestudy was to calculate radiation doses for patients and cancer risk for patients during proceduresby department. In this study, a total of 288 patients (Male: 182, female: 106), conducted using aERCP system from January to March of 2016, were analyzed. A total of 288 patients were eligible,regardless of gender, with an average age of 61.28±13.4 (19~91) years. The procedures wereperformed in the radiology department using a fluoroscopy X-ray machine (multidiagnost ELEVAFD). In study, fluoroscopy time, DAP (Dose area product) values, effective dose and cancer riskby department were measured. DAP measurements can be used to estimate an effective dose (ED)and cancer risk to patients undergoing ERCP. Mean fluoroscopy time of all departments was7.05±7 min (0.4~71.2 min). LTS (liver transplantation & hepatobiliary surgery) had the highestfluoroscopy time with 10.58±7.93 min, and HBP (hepatobiliary pancreatic surgery) had thelowest fluoroscopy time with 3.38±1.93 min (p<0.01). Mean DAP values of all departments was8.40±7.77 mGy·cm2. LTS had the highest DAP value with 11.96±9.03 mGy·cm2, and HBP hadthe lowest DAP value with 4.15±2.73 mGy·cm2 (p<0.01). Mean effective dose of all departmentswas 0.68±0.63 mSv. LTS had the highest effective dose with 0.97±0.73 mSv, and HBP had thelowest effective dose with 0.34±0.22 mSv (p<0.01). Mean cancer risk of all departments was1.007±0.006 time, and LTS had the highest cancer risk with 1.06 time (p<0.01). LTS had thehighest cancer risk with 1.06 time but the risk is low in the approximate 1.0 times. TherapeuticERCP procedure is beneficial to the patient, but may be necessary comprehensive managementand efforts to reduce radiation dose.

몬테카를로 코드를 활용한 표준 감마선 조사장치의 성능평가에 관한 연구

박원석 ( Won-seok Park ),허승욱 ( Seung-uk Heo ),김장오 ( Jang-oh Kim ),민병인 ( Byung-in Min ) 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.2

본 연구는 표준 감마선 조사장치의 유효빔 크기를 실측과 시뮬레이션의 결과를 비교하여 유효빔 영역의 결정에 유용한 수단을 제공하고자 하였다 시뮬레이션과 전리함을 이용한 실측의 결과는 공기커마율의 경우는 상대오차 4.5~7.3% 범위에 분포하였다. 유효빔 영역의 크기는 시뮬레이션의 경우 수평 방향 27cm, 수직 방향 21.6cm로 구현되었고, 필름을 이용한 실측결과는 수평 방향 26.5cm, 수직 방향 21.9cm로 유사한 결과가 도출되었다. 수평방향의 상대오차는 1.85%, 수직 방향은 1.38% 이며 유효빔 영역도 감마선장을 중심으로 유사하게 분포하였다. 감마선 조사장치에 있어서 시뮬레이션의 유효성이 충분함을 확인하였다. 특히 공기커마율보다 유효빔 크기의 상대오차가 적은 것은 빔의 크기가 표준선원의 용량보다는 기하학적 요인으로 결정되기 때문인 것으로 판단된다. 향후 시뮬레이션을 이용한 광자 에너지 분포도의 신뢰성을 높이기 위한 연구가 필요 할 것이다. In this study, we compared the measured values of the effective beam size of standard gamma irradiator with the simulation results to provide a useful means to the effective beam area determination. Results of the simulation and measured using ion chamber was distributed in a relative error of 4.5 ~ 7.3% of the case of air kerma rate. The size of the effective beam area is when the simulation was implemented in the horizontal direction 27cm, 21.6cm vertical direction, the measured result using a film was obtained similar results with the horizontal direction 26.5cm, 21.9cm vertical direction. The relative error in the horizontal direction is 1.85% and 1.38% vertical effective beam area was also similarly distributed around the field gamma rays. As a result of the study, it was confirmed that the effectiveness of the simulation was sufficient for the gamma irradiation system. In particular, it is small relative errors in the effective beam size than the air kerma rate is considered to be due to the size of the beam is determined by geometric factors rather than the capacity of the standard source. A further study is needed to improve the reliability of the photon energy distribution diagram using simulation.

A Study on the Performance Evaluation of Standard Gamma Irradiation System Using Monte Carlo Code

Won-Seok Park(박원석),Seung-Uk Heo(허승욱),Jang-Oh Kim(김장오),Byung-In Min(민병인) 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.2

In this study, we compared the measured values of the effective beam size of standard gamma irradiator with the simulation results to provide a useful means to the effective beam area determination. Results of the simulation and measured using ion chamber was distributed in a relative error of 4.5 ~ 7.3% of the case of air kerma rate. The size of the effective beam area is when the simulation was implemented in the horizontal direction 27cm, 21.6cm vertical direction, the measured result using a film was obtained similar results with the horizontal direction 26.5cm, 21.9cm vertical direction. The relative error in the horizontal direction is 1.85% and 1.38% vertical effective beam area was also similarly distributed around the field gamma rays. As a result of the study, it was confirmed that the effectiveness of the simulation was sufficient for the gamma irradiation system. In particular, it is small relative errors in the effective beam size than the air kerma rate is considered to be due to the size of the beam is determined by geometric factors rather than the capacity of the standard source. A further study is needed to improve the reliability of the photon energy distribution diagram using simulation. 본 연구는 표준 감마선 조사장치의 유효빔 크기를 실측과 시뮬레이션의 결과를 비교하여 유효빔 영역의 결정에 유용한 수단을 제공하고자 하였다. 시뮬레이션과 전리함을 이용한 실측의 결과는 공기커마율의 경우는 상대오차 4.5~7.3% 범위에 분포하였다. 유효빔 영역의 크기는 시뮬레이션의 경우 수평 방향 27cm, 수직 방향 21.6cm로 구현되었고, 필름을 이용한 실측결과는 수평 방향 26.5cm, 수직 방향 21.9cm로 유사한 결과가 도출되었다. 수평방향의 상대오차 는 1.85%, 수직 방향은 1.38% 이며 유효빔 영역도 감마선장을 중심으로 유사하게 분포하였다. 감마선 조사장치에 있어서 시뮬레이션의 유효성이 충분함을 확인하였다. 특히 공기커마율보다 유효빔 크기의 상대오차가 적은 것은 빔의 크기가 표준선원의 용량보다는 기하학적 요인으로 결정되기 때문인 것으로 판단된다. 향후 시뮬레이션을 이용한 광자 에너지 분포도의 신뢰성을 높이기 위한 연구가 필요할 것 이다.