소아 흉부 X-ray 검사 시 Exposure field 조정에 따른 유효선량의 평가

안준오(June-Oh Ahn):정지상(Ji-Sang Jung):김성식(Sung-Sik Kim):안치복(Chi-Bok An),박순규(Sun-Kyu Park),임재식(Jae-Sik Lim) 대한영상의학기술학회 2016 대한영상의학기술학회 논문지 Vol.2016 No.1

목 적 : 소아 흉부 X-ray 검사 시, DR system에서의 적절한 Exposure field 조정을 통해 유효 Exposure Index범위 내의 영상의 유효선량과 각 장기에서의 유효선량 및 cancer risk 확률을 비교함으로써, field size 조정에 따른 유효선량 및 장기 유효선량을 평가하기 위함에 있다. 대상 및 방법 : 본원의 디지털 진단용 엑스선 촬영장치인 Discovery XR656(GE Healthcare, Korea)을 사용하여, 소아 흉부팬텀을 이용한 Chest AP검사를 수행하였다. IEC 61257-1에서 권고하는 General Digital Radiography의 선질 RQA3 조건에 맞춰 SID는 110cm, 노출조건은 관전압 50kVp로 고정하고, mAs range는 위의 장비에서 적용할 수 있는 범위 안에서 0.5,0.63,0.8,1.0,1.25,1.6,2.0,2.5,3.2mAs으로 변화를 주며 exposure하였다. 위의 조건에 따라, Exposure field size를 20cmx20cm, 30cmx30cm, 40x40cm, 총 3그룹으로 분류하였다. 각 조건에서 총 243번의 exposure를 한 뒤, 이의 평균값을 구하였다. 또한 획득 된 영상들을 Exposure Index를 기준으로 세 그룹으로 분류하고, 이 중에서 유효 Exposure Index범위 내의 영상들만을 분류하여 DAP를 계산하고 a PC-Based Monte Carlo Program 2.0(PCXMC)를 사용, 유효선량을 도출하였다. 위에서 얻은 유효선량을 기준으로 DR system에서 소아 Chest AP(PED)검사 시, Exposure field size에 따른 유효선량 경향을 분석하였다. 또한 각 조건에서 선량계로 측정한 실측 선량 값을 측정하여 Phantom에서 흡수한 실제 선량 값을 비교하였다. 더불어, PCXMC2.0을 사용하여 각 장기에서의 유효선량과 cancer risk 확률도 계산하였다. 결 과 : 적정 노출 군(DI: -3.0이상, 2.0이하)에 포함된 영상 중에서 동일한 mAs를 기준으로 Field size가 증가할 때의 유효선량은 field size가 늘어남에 따라 유효선량도 증가하는 경향을 보였다. 반면 선량계를 통해 측정한 phantom에서의 실측 선량 값에서는 큰 변화가 없었다. 또한 PCXMC2.0을 이용한 각 장기에서의 유효선량 및 cancer risk 확률은 증가하는 경항을 보였다. 결 론 : 각 조건으로부터 획득된 영상의 Exposure Index 값을 기준으로 분류한 영상들의 결과 값을 통해 소아 Chest AP(PED)검사 시, 의료 방사선 종사자의 적절한 Field size 조정을 통해 소아 환자의 피폭 저감화 및 방사선 방어에 일조할 수 있다고 사료된다. Purpose : Pediatric chest radiography, DR system at the effective dose of the proper image within the range Exposure Index Exposure field through the appropriate adjustments by comparing the effective dose and cancer risk probability in each organ, It is in order to assess the effective dose and organ dose of the active field size adjustment. Materials and Methods : Using the present system of digital diagnostic X-rays taken of Discovery XR656 (GE Healthcare, Korea), Chest AP tests were performed using a pediatric chest phantom. SID is 110cm, exposure conditions and secure it with the tube voltage 50kVp, mAs range gives exposure to changes in 0.5,0.63,0.8,1.0,1.25,1.6,2.0,2.5,3.2mAs was within the range that can be applied to the above equipment. Depending on the conditions above, Exposure field size of 20cmx20cm, 30cmx30cm, 40x40cm, were divided into three groups. After a total of 243 times in each exposure condition, its average value was determined. Classified into three groups of the acquired image relative to the Exposure Index, and classifies the image only in the effective Exposure Index range from this calculate the DAP to use a PC-Based Monte Carlo Program 2.0 (PCXMC), derived the effective dose. Based on the effective dose obtained above test, were analyzed according to the effective dose trend Exposure field size. In addition, by measuring dose actually measured value measured by a dosimeter in each condition the actual dose value was measured by absorption at Phantom. In addition, by using the calculated PCXMC2.0 the effective dose and the probability of cancer risk from each organ. Result : Among the images included in the appropriate exposure group relative to the same mAs effective dose to increase the Field size tended to increase the effective dose is increased. On the other hand, the actually measured value of the dose measured by the dosimeter in phantom unchanged. Effective dose and cancer risk probability in each organ using PCXMC2.0 also showed a tendency to increase. Conclusion : Through the results of the classification based on the DI value of the images obtained from each condition, through the appropriate Field size adjustment of medical radiation workers, it is thought that exposure can contribute to the reduction of Radiation Protection and pediatric patients.

방사선 취급 작업종사자의 개인 피폭선량(Individual Dose)에 관한 연구

동경래,김창복,박용순,지연상,김치년,원종욱,노재훈 한국실내환경학회 2009 한국실내환경학회지 Vol.6 No.1

The importance of managing the exposure to radiation for radiological technologist is becoming more conspicuous as modern medical care increases the number of hospital exams involving radiation and as work of radiological technologists expand and increase in areas using advanced medical equipment for diagnosis and treatment purposes involving radiation. Measurements for individual exposure dose to radiation can differ according to the equipment and facilities in the work environment and the average number of exposures an individual is involved in. Therefore, systematic and reasonable controls on the exposure dose to radiation can be attained from core data. Shallow dose/Deep dose measurements were taken according to the year of the measurement, the technologist’s occupation post, gender, department, and age over a five year period from January 1, 2003 to December 31, 2007 using a sample of radiological technologists from ten general hospitals throughout S. Korea. When comparing individual exposure dose of each radiological technologist, there was no significant difference in the mean exposure dose according to the year the measurement was taken (p>0.05). Mean exposure dose for Deep/Shallow according to gender showed that men received significantly higher exposure dose than women (p<0.001). Mean exposure dose for Deep/Shallow according to age showed an increase in exposure dose as age decreases, however, it was not statistically significant (p>0.05). According to occupation post, technologists working in nuclear medicine received significantly higher dose than other occupation posts (p<0.001). The results of individual exposure dose were under the dose limits in accordance to all nuclear regulations. Furthermore, since stochastic effects may occur with long-term exposure to low level radiation, individual exposure dose data was thoroughly managed and the principle of As Low as Reasonably Achievable (ALARA) was implemented when establishing the design of this study.

방사선 취급 작업종사자의 개인 피폭선량(Individual Dose)에 관한 연구

동경래(Kyung-Rae Dong) ⋅김창복(Chang-Bok Kim) ⋅박용순(Yong-Soon Park) ⋅지연상(Yeon-Sang Ji) ⋅김치년(Chi-Nyon Kim) ⋅원종욱(Jong-Uk Won) ⋅노재훈(Jae-Hoon Roh) 한국실내환경학회 2009 한국실내환경학회지 Vol.6 No.1

The importance of managing the exposure to radiation for radiological technologist is becoming more conspicuous as modern medical care increases the number of hospital exams involving radiation and as work of radiological technologists expand and increase in areas using advanced medical equipment for diagnosis and treatment purposes involving radiation. Measurements for individual exposure dose to radiation can differ according to the equipment and facilities in the work environment and the average number of exposures an individual is involved in. Therefore, systematic and reasonable controls on the exposure dose to radiation can be attained from core data. Shallow dose/Deep dose measurements were taken according to the year of the measurement, the technologist’s occupation post, gender, department, and age over a five year period from January 1, 2003 to December 31, 2007 using a sample of radiological technologists from ten general hospitals throughout S. Korea. When comparing individual exposure dose of each radiological technologist, there was no significant difference in the mean exposure dose according to the year the measurement was taken (p>0.05). Mean exposure dose for Deep/Shallow according to gender showed that men received significantly higher exposure dose than women (p<0.001). Mean exposure dose for Deep/Shallow according to age showed an increase in exposure dose as age decreases; however, it was not statistically significant (p>0.05). According to occupation post, technologists working in nuclear medicine received significantly higher dose than other occupation posts (p<0.001). The results of individual exposure dose were under the dose limits in accordance to all nuclear regulations. Furthermore, since stochastic effects may occur with long-term exposure to low level radiation, individual exposure dose data was thoroughly managed and the principle of As Low as Reasonably Achievable (ALARA) was implemented when establishing the design of this study.

선량 환산 관례를 이용한 생애유효선량 및 라돈피폭 위험도예측: 대학 강의실 라돈농도 중심으로

이재승,권대철 대한의용생체공학회 2018 의공학회지 Vol.39 No.6

The indoor radon concentration was measured in the lecture room of the university and the radon concentration was converted to the amount related to the radon exposure using the dose conversion convention and compared with the reference levels for the radon concentration control. The effect of indoor radon inhalation was evaluated by estimating the life effective dose and the risk of exposure. To measure the radon concentration, measurements were made with a radon meter and a dedicated analysis Capture Ver. 5.5 program in a university lecture room from January to February 2018. The radon concentration measurement was carried out for 5 consecutive hours for 24 hours after keeping the airtight condition for 12 hours before the measurement. Radon exposure risk was calculated using the radon dose and dose conversion factor. Indoor radon concentration, radon exposure risk, and annual effective dose were found within the 95% confidence interval as the minimum and maximum boundary ranges. The radon concentration in the lecture room was 43.1-79.1 Bq/m3, and the maximum boundary range within the 95% confidence interval was 77.7 Bq/m3. The annual effective dose was estimated to be 0.20-0.36 mSv/y (mean 0.28 mSv/ y). The life-time effective dose was estimated to be 0.66-1.18 mSv (mean 0.93 ± 0.08 mSv). Life effective doses were estimated to be 0.88-0.99 mSv and radon exposure risk was estimated to be 12.4 out of 10.9 per 100,000. Radon concentration was measured, dose effective dose was evaluated using dose conversion convention, and degree of health hazard by indoor radon exposure was evaluated by predicting radon exposure risk using nominal hazard coefficient. It was concluded that indoor living environment could be applied to other specific exposure situations.

High Dose Computed Tomography검사의 Exposure Dose 측정 및 평가

김주(Joo Kim),권성옥(Seong Ohk Kwon),김기홍(Ki Hong Kim),서동수(Dong Soo Suh),최준호(Joon Ho Choi) 대한CT영상기술학회 2007 대한CT영상기술학회지 Vol.9 No.1

Purpose Charge of patient decreased on account of National Health Insurance benefit in CT examination. Scan time is reduced by generalization of spinal CT and utility of MDCT technic. Accuracy of diagnosis has improved because of up-to-date software. As a result, coefficient of utilization on CT examination increased and exposure dose is reduced by improved performance of detector and CT unit. It was necessary to use Thin slice in other to acquire a quantity of data but radiation hazard of adapted Multi-phase study increased. This Study evaluates exposure dose in CT examination. Objects and Methods CT head arteriography protocol is 20kVp, 100~300mAs, tube rotation time 0.5 or 1sec, total scan time 53sec, neck arteriography protocol is 120kVp, 150~300mAs, tube rotation time 0.5, 0.75 or 1sec, total scan time 67sec. CT OMU protocol is 120kVp, 120mAs, tube rotation time 1sec, total scan time 30sec. CT perfusion protocol is 80kVp, 200mAs, tube rotation time 1sec, total scan time 40sec. CT coronary artery protocol is 120kVp, pre : 20mAs, coronary artery : 600mAs, tube rotation time 0.5, or 0.37sec, total scan time 32sec. CT 3D intestine protocol is 120kVp, 200mAs, tube rotation time 0.5sec, total scan time 88sec. We located Ionization chamber at the center brain and abdomen acrylic and measure exposure dose. Results Exposure dose of CT head arteriography is 12.6R, exposure dose of CT neck arteriography is 23.83R, exposure dose of CT OMU is 12.6R, exposure dose of CT coronary artery is 6.15R, exposure dose of CT 3D intestine is 9.68R. We measured 5 times multi-phase study of CT neck arteriography, CT 3D intestine : 5 times, CT OMU : 2 times, CT perfusion : 2 times, CT coronary artery : 3 times Conclusion Exposure dose of CT head arteriography is 12. 6R which is maximum value and exposure dose of CT OMU is 12.6R which is minimum value. there is not only benefit but also a loss

A Study of Injection Dose for Patients and Exposure Dose for Technologists from the PET/CT Systems

박훈희,오기백,이승재,반영각,강천구,임한상,김재삼,이창호,Park, Hoon-Hee,Oh, Ki-Beak,Lee, Seung-Jae,Bhan, Young-Kag,Kang, Chun-Goo,Lim, Han-Sang,Kim, Jae-Sam,Lee, Chang-Ho The Korean Society of Nuclear Medicine Technology 2011 핵의학 기술 Vol.15 No.1

PET/CT검사에서 $^{18}F$-FDG가 가장 널리 이용되며, 장비의 물리적 특성에 따라 환자 주입 $^{18}F$-FDG량이 다르게 권고되고 있다. 또한, 검사 특성상 방사선종사자와 환자의 접촉으로 인하여 방사선의 피폭이 불가피하기에, 본 연구에서는 각기 다른 PET/CT 장비를 대상으로 환자에게 주입되는 $^{18}F$-FDG가 방사선 종사자에게 미치는 피폭선량과의 관계를 분석하였다. 총 3대의 각각 다른 PET/CT (Scanner 1 (S1) : 0.15 mCi/kg, Scanner 2 (S2) : 0.17 mCi/kg, Scanner 3 (S3) : 0.12 mCi/kg)를 대상으로 각 장비에 숙련도를 고려하여 총 6명의 방사선종사자를 5개월간 순환근무 하였고, 하루에 검사하는 환자수를 일정하게 유지하였다. 또한, 검사 진행 방법을 유사하게 유지하고, 방사선종사자의 개인피폭선량계인 열형광유리선량계(TLD)를 매월 판독 하여 분석하였다. 개인의 월별 평균 피폭선량은 장비에 따라 S1은 0.76 mSv, S2는 0.93 mSv, S3는 0.47 mSv였다. 피폭선량은 개인 최대 1.12 mSv, 최저 0.42 mSv로 숙련도와 경험에 따라 유의한 차이를 보였고, 또한 각 주입량에 따른 PET/CT의 종류에 따라 피폭선량은 유의한 상관관계를 나타냈다. 본 연구를 통하여 주입 $^{18}F$-FDG가 적을수록 방사선종사자의 피폭선량이 낮았다. 또한, 개인숙련도에 따라 피폭선량이 감소하였으나, 장비의 특성에 따라 적은 방사성의약품 주입량의 영향이 방사선종사자의 피폭선량을 현저하게 감소할 수 있기에 이에 대한 연구가 보다 활성화 되어야 할 것이다. Purpose: It appears the different value when the injection dose is calculating for patients on each PET/CT systems. It directly affects the technologists' radiation exposed dose. We studied the effect of the variable injection doses from several PET/CT systems to exposure dose for technologists. Materials and Methods: Six technologists have worked for 5 months through unit rotations with 3 PET/CT systems {Scanner 1 (S1): 0.15 mCi/kg, Scanner 2 (S2): 0.17 mCi/kg, Scanner 3 (S3): 0.12 mCi/kg}. Eighteen to 19 patients have had examinations per a day on each PET/CT systems. Examination parameters were adjusted to the same. TLDs were used for checking the exposure dose of technologists. Results: Each technologists' the monthly average exposure dose was as follows; S1: 0.76 mSv, S2: 0.93 mSv, S3: 0.47 mSv. The maximum exposure dose was 1.12 mSv, and minimum was 0.42 mSv. The results showed significance in the correlation between the PET/CT system and the exposure dose (p<0.005). Conclusion: When the amount of injection dose was small, the exposure dose was decreased not only the patients but also the technologists. The exposure dose was decreased by the individual proficiency of technologists. However, the low injection dose can highly reduce the exposure dose for technologist so that there will be needed to following studies.

CT 촬영 조건에 따른 PET 영상의 변화

박재윤 ( Jae-yoon Park ),김정훈 ( Jung-hoon Kim ),이용기 ( Yong-ki Lee ) 한국방사선학회 2019 한국방사선학회 논문지 Vol.13 No.3

다양한 촬영 조건의 CT 감쇠 지도가 PET 영상에 영향을 미치는지 알아보기 위하여 다양한 kVp와 mA 조건에서 Uniformity phantom 영상의 신호 강도 (SI; Signal Intensity)와 표준 섭취율 계수 (SUV; Standardized Uptake Value)를 측정하고, CTDI(Computed Tomography Dose Index)를 통해 각 조건에 따른 피폭선량을 측정하였다. 또한 동일한 조건에서 Resolution phantom의 반치폭 (FWHM; Full Width at Half Maximum)을 측정하여 CT의 kVp와 mA에 따른 PET 영상의 화질 변화에 대하여 정량적으로 알아보고자 하였다. 연구 결과, CT의 촬영 조건은 PET 영상에는 영향을 주지 않는 것으로 나타났으나, CT의 촬영 조건이 감소하게 되면 방사선 피폭이 감소하게 되지만 영상에 영향을 미치게 되므로 향후 진단이 가능한 CT 화질을 유지하면서 방사선 피폭을 최소화할 수 있는 양전자 방출 단층 촬영 (PET/CT; Positron Emission Tomography / Computed Tomography)의 촬영 조건에 대한 연구가 지속적으로 되어야 할 것이다. PET-CT improves performance and reduces the time by combining PET and CT of spatial resolution, and uses CT scan for attenuation correction. This study analyzed PET image evaluation. The condition of the tube voltage and current of CT will be changed using. Uniformity phantom and resolution phantom were injected with 37 MBq ¹⁸F (fluorine ; 511 keV, half life - 109.7 min), respectively. PET-CT (Biograph, siemens, US) was used to perform emission scan (30 min) and penetration scan. And then the collected image data were reconstructed in OSEM-3D. The same ROI was set on the image data with a analyzer (Vinci 2.54, Germany) and profile was used to analyze and compare spatial resolution and image quality through FWHM and SI. Analyzing profile with pre-defined ROI in each phantom, PET image was not influenced by the change of tube voltage or exposure dose. However, CT image was influenced by tube voltage, but not by exposure dose. When tube voltage was fixed and exposure dose changed, exposure dose changed too, increasing dose value. When exposure dose was fixed at 150 mA and tube voltage was varied, the result was 10.56, 24.6 and 35.61 mGy in each variables (in resolution phantom). In this study, attenuation image showed no significant difference when exposure dose was changed. However, when exposure dose increased, the amount of dose that patient absorbed increased too, which indicates that CT exposure dose should be decreased to minimum to lower the exposure dose that patient absorbs. Therefore future study needs to discuss the conditions that could minimize exposure dose that gets absorbed by patient during PET-CT scan.

CT 촬영 조건에 따른 PET 영상의 변화

박재윤,김정훈,이용기 한국방사선학회 2019 한국방사선학회 논문지 Vol.13 No.3

다양한 촬영 조건의 CT 감쇠 지도가 PET 영상에 영향을 미치는지 알아보기 위하여 다양한 kVp와 mA 조건에서 Uniformity phantom 영상의 신호 강도 (SI; Signal Intensity)와 표준 섭취율 계수 (SUV; Standardized Uptake Value)를 측정하고, CTDI(Computed Tomography Dose Index)를 통해 각 조건에 따른 피폭선량을 측정하였다. 또한 동일한 조건에서 Resolution phantom의 반치폭 (FWHM; Full Width at Half Maximum)을 측정하여 CT의 kVp와 mA에 따른 PET 영상의 화질 변화에 대하여 정량적으로 알아보고자 하였다. 연구 결과, CT의 촬영 조건은 PET 영상에는 영향을 주지 않는 것으로 나타났으나, CT의 촬영 조건이 감소하게 되면 방사선 피폭이 감소하게 되지만 영상에 영향을 미치게 되므로 향후 진단이 가능한 CT 화질을 유지하면서 방사선 피폭을 최소화할 수 있는 양전자 방출 단층 촬영 (PET/CT; Positron Emission Tomography / Computed Tomography)의 촬영 조건에 대한 연구가 지속적으로 되어야 할 것이다. PET-CT improves performance and reduces the time by combining PET and CT of spatial resolution, and uses CT scan for attenuation correction. This study analyzed PET image evaluation. The condition of the tube voltage and current of CT will be changed using. Uniformity phantom and resolution phantom were injected with 37 MBq 18F (fluorine ; 511 keV, half life - 109.7 min), respectively. PET-CT (Biograph, siemens, US) was used to perform emission scan (30 min) and penetration scan. And then the collected image data were reconstructed in OSEM-3D. The same ROI was set on the image data with a analyzer (Vinci 2.54, Germany) and profile was used to analyze and compare spatial resolution and image quality through FWHM and SI. Analyzing profile with pre-defined ROI in each phantom, PET image was not influenced by the change of tube voltage or exposure dose. However, CT image was influenced by tube voltage, but not by exposure dose. When tube voltage was fixed and exposure dose changed, exposure dose changed too, increasing dose value. When exposure dose was fixed at 150 mA and tube voltage was varied, the result was 10.56, 24.6 and 35.61 mGy in each variables (in resolution phantom). In this study, attenuation image showed no significant difference when exposure dose was changed. However, when exposure dose increased, the amount of dose that patient absorbed increased too, which indicates that CT exposure dose should be decreased to minimum to lower the exposure dose that patient absorbs. Therefore future study needs to discuss the conditions that could minimize exposure dose that gets absorbed by patient during PET-CT scan.

흉부 X-ray 검사 시 DEI 값에 따른 적정 관전압에 관한 고찰

채정현(Jeong-hyun, Chae),심지나(Ji-na, Sim),정지상(Ji-sang, Jung),한영수(Yung-soo, Han),진덕은(Duk-eun, Jin),강성호(Sung-ho, Kang),임재식(Jae-sik, Lim) 대한영상의학기술학회 2014 대한영상의학기술학회 논문지 Vol.2014 No.1

목 적 : 흉부 X-ray 검사 시, DR 시스템에 적절한 유효 Detector Exposure Index (DEI) 범위 내의 영상의 Dose Area Product (DAP)값과 유효선량을 비교함으로써, high kVp 사용의 적합성을 영상의 퀄리티나 환자선량 측면에서 평가하기 위함에 있다. 대상 및 방법 : GE definium 8000을 사용하여 흉부팬텀을 이용한 Chest PA 검사를 재현하였다. kVp range는 60~130 kVp로 정하였다. mAs range는 앞의 정한 kVp에 따라 Auto Exposure Control (AEC) 시스템에 의거하여 60kVp에서는 40mAs, 130kVp에서는 2.5mAs로 정하였고 mAs range는 2.5mAs에서, 3.2mAs, 4.0mAs, 5.0mAs, 6.3mAs, 8.0mAs, 10mAs, 12.5mAs, 16mAs, 20mAs, 25mAs, 32mAs, 40mAs로 설정하였다. 위의 kVp 조건에 따라, 각각의 mAs로 총 104번 을 exposure한 뒤, 세브란스 선량관리 시스템으로 전송된 영상의 DEI와 DAP를 획득할 수 있었다. 획득한 영상을 유효한 DEI 범위의 영상들(0.2-0.6 : 정상군)과 DEI 0.2 이하, DEI 0,6 이상인 영상들 을 각각 분류하고 DAP을 이용하여 a PC-Based Monte Carlo Program 2.0 (PCXMC)을 통해 유효 선량을 계산하였다. 각각의 측정한 데이터를 DEI기준, DAP기준, 유효선량의 기준으로 분류한 후, DR 시스템에서 Chest PA 검사 시 적절한 kVp 범위를 분석하였다. 각 그룹의 유의성은 SPSS(version 12.0, SPSS Inc Chicago, IL, USA) 통계 패키지 프로그램을 사용하여 kruskal-wallis test와 사후검정으로 mann -whitney test를 시행하여 검증 하였으며 검증에 사용된 신뢰구 간은 95 %이다.    결 과 : 위의 실험을 통해 얻은 유효한 DEI 범위(0.2-0.6)에 포함된 영상의 평균 kVp는 75.29 kVp 이고 평균  mAs는 8.58 mAs, 평균 DAP는 1.73 mGy·cm², 유효선량은 0.018 mSv 이었다. 유효선 량별로 수집한 군에서 최저의 유효선량인 0.011449 mSv가 측정된 조건은 70kV, 5mAs, DAP 1.06mGy·cm²,이었다. 실측값 DAP에 따른 군에서는 최저 DAP 인 0.885 mGy·cm²에서 조건은 90kV, 2.5mAs, 0.013mSv이 측정되었다. 유의성 검증 결과, 유효 DEI 범위 내의 유효선량에서 유의한 차 이(p<0.05)가 있었고, 전체 DEI 그룹에서 대해서는 0.2 이하 범위와 0.2이상 0.6 이하의 범위, 0.6이상의 범위의 유효선량과 DAP에서 모두 유의한 차이가 있었다.(p<0.05)  결 론 : 각각의 DEI, DAP, 유효선량 기준으로 분류된 데이터를 통해 현재 사용되고 있는 흉부 검사 시 high kVP기법은 환자 피폭적인 측면과 영상의 퀄리티적인 측면에서 재고할 필요성이 있다고 사료된다. Purp os e : This study is to evaluate the suitability of the use of high kVp technique for Chest PA examination in DR system by comparing with Dose Area Product and effective dose of chest images in efficient Detector Exposure Index(DEI) range.    Materials and Methods :  We set up situation of Chest PA examination with GE definium 8000. kVp range is 60~130 kVp. Range of mAs is 40 mAs at 60kVp, 2.5mAs at 130kVp  through Auto Exposure Control system(AEC) in accordance with kVp range we set, then we set up mAs range from 2.5mAs, 3.2mAs, 4.0mAs, 5.0mAs, 6.3mAs, 8.0mAs, 10mAs, 12.5mAs, 16mAs, 20mAs, 25mAs, 32mAs to 40mAs. We exposured 104 times as the kVp condition we set, then all images are sent to the Severance Dose management system which we can acquire DEI and DAP data. We classified acquired images into several DEI groups–under 0.2, between 0.2 and 0.6, over 0.6, then calculated Effective Dose with DAP by using a PC-Based Monte Carlo Program 2.0(PCXMC). After classifying acquired data into 3 groups according to DEI, DAP and effective dose, we analyzed suitable kVp range for Chest PA examination in DR system. SPSS(version 12.0, SPSS Inc Chicago, IL, USA) is used for statistical significance, which is Kruskal-Wallis test and Mann-Whitney test to each group. Confidence interval is 95%.  Res ult : Average kVp of image in efficient DEI range from the experiment is 75.29 kVp, mAs is 8.58 mAs, DAP is 1.73 mGy·cm² and effective dose is 0.018 mSv. The condition which 0.011449 mSv is acquired as the lowest effective dose is 70 kVp, 5mAs, DAP 1.06mGy·cm² in groups classified with effective dose. Another condition which 0.885mGy·cm² is acquired as the lowest DAP is 90kV, 2.5mAs, and Its effective dose is 0.013mSv. As a result of statistic significance test, there is significance difference in effective dose of the efficient DEI range group(p<0.05) and significance difference is found in whole DEI groups of under 0.2, between 0.2 and 0.6, over 0.6(p<0.05)  Conc lus ion : According to each classified data with DEI, DAP, Effective dose, high kVp technique for Chest PA examination which is currently used is need to be reconsidered in patient exposure and image quality.

의료기관 핵의학 종사자의 직무 별 개인피폭선량에 관한 연구

강천구,오기백,박훈희,오신현,박민수,김정열,이진규,나수경,김재삼,이창호,Kang, Chun-Goo,Oh, Ki-Baek,Park, Hoon-Hee,Oh, Shin-Hyun,Park, Min-Soo,Kim, Jung-Yul,Lee, Jin-Kyu,Na, Soo-Kyung,Kim, Jae-Sam,Lee, Chang-Ho 대한핵의학기술학회 2010 핵의학 기술 Vol.14 No.2

본 연구는 방사성동위원소의 의학적 이용도가 증가함에 따라 의료기관 핵의학과 방사선 관계종사자의 직무 별 방사선 이용에 대한 개인 방사선 피폭선량의 실태를 파악하여, 방사선 위험에 대해 경각심을 고취시키고, 방사선 관계종사자들에게 안전관리와 합리적인 피폭선량 관리에 도움을 주고자 분석하였다. 2007년 1월 1일부터 2009년 12월 31일까지 의료기관에서 근무하는 핵의학 방사선 관계종사자로 분류되어 개인 방사선피폭선량 측정을 정기적, 연속적으로 3년 간 조사 관리된 40명의 종사자를 대상으로 직종 별, 영상실 별, 연령 별, 선량구간 별, 직무 별 관련업무를 파악하여 심부선량에 대하여 연간평균피폭선량을 각각 분석하였다. 분석법으로는 빈도분석과 ANOVA를 시행하였다. 3년 간 영상실 별 연간피폭선량은 PET 및 PET/CT 영상실이 11.06~12.62 mSv로 가장 높은 피폭선량을 보였고, 감마카메라 주사실이 11.72 mSv로 높았으며, 직종 별 연간평균피폭선량은 임상병리사가 8.92 mSv로 가장 높았고, 방사선사 7.50 mSv, 간호사 2.61 mSv, 연구원 0.69 mSv, 접수 0.48 mSv, 의사 0.35 mSv 순으로 나타났으며, 세부업무에 따른 직무별 연간평균피폭선량은 PET 및 PET/CT 업무가 12.09 mSv로 가장 높은 피폭선량을 보였으며, 감마카메라 주사실이 11.72 mSv, 싸이크로트론 관련 합성 업무 8.92 mSv, 감마카메라 영상업무 4.92 mSv, 치료 및 안전관리 2.98 mSv, 간호사 업무 2.96 mSv, 관리 업무 1.72 mSv, 영상분석 업무 0.92 mSv, 판독업무 0.54 mSv, 접수업무 0.51 mSv, 연구업무 0.29 mSv 순으로 나타났다. 선량구간 별 연간평균피폭선량은 연구대상자의 15명(37.5%)이 1 mSv이하의 선량분포와 5명(12.5%)이 1.01~5.0 mSv이하의 선량분포를 가지고 있었고, 5.01~10.0mSv에서 14명(35.0%), 10.01~20.0 mSv에서 6명(15.0%)의 분포로 분석되었다. 연령에 따른 연간평균피폭선량은 방사선사 직종에서는 25~34세 종사자가 8.69 mSv로 가장 높은 평균선량을 보였고, 근무기간에 따른 연간평균피폭선량은 방사선사 직종에서 5~9년 종사자가 9.5 mSv로 가장 높은 평균선량을 나타냈다. 고용형태에 따른 연간평균피폭선량은 정규직 임상병리사 8.92 mSv, 방사선사 7.82 mSv, 계약직 방사선사 7.55 mSv, 인턴직 방사선사 5.62 mSv, 계약직 간호사 2.61 mSv, 정규직 연구원 0.69 mSv, 접수 0.55 mSv, 의사 0.35mSv 순으로 피폭을 받는 것으로 나타났다. 이와 같은 결과로 볼 때 의료기관에서 근무하는 핵의학 방사선 관계종사자의 대부분이 현재의 방사선 안전관리가 실효성 있게 이루어지고 있었으며, 직무특성에 따라 많은 차이가 있는 것을 알게 되었다. 그러나 방사선 피폭을 최소화시키는 노력이 필요하며, 이를 위해서 체계적 교육과 합리적 피폭량 관리를 위한 체계가 필요하다고 사료된다. Purpose: With increasing medical use of radiation and radioactive isotopes, there is a need to better manage the risk of radiation exposure. This study aims to grasp and analyze the individual radiation exposure situations of radiation-related workers in a medical facility by specific job, in order to instill awareness of radiation danger and to assist in safety and radiation exposure management for such workers. Materials and Methods: 1 January 2007 to 31 December 2009 to work in medical institutions are classified as radiation workers Nuclear personal radiation dosimeter regularly, continuously administered survey of 40 workers in three years of occupation to target, Imaging Unit beautifully, age, dose sector, job function-related tasks to identify the average annual dose for a deep dose, respectively, were analyzed. The frequency analysis and ANOVA analysis was performed. Results: Imaging Unit beautifully three years the annual dose PET and PET/CT in the work room 11.06~12.62 mSv dose showed the highest, gamma camera injection room 11.72 mSv with a higher average annual dose of occupation by the clinical technicians 8.92 mSv the highest, radiological 7.50 mSv, a nurse 2.61 mSv, the researchers 0.69 mSv, received 0.48 mSv, 0.35 mSv doctors orderly, and detail work employed the average annual dose of the PET and PET/CT work is 12.09 mSv showed the highest radiation dose, gamma camera injection work the 11.72 mSv, gamma camera imaging work 4.92 mSv, treatment and safety management and 2.98 mSv, a nurse working 2.96 mSv, management of 1.72 mSv, work image analysis 0.92 mSv, reading task 0.54 mSv, with receiving 0.51 mSv, 0.29 mSv research work, respectively. Dose sector average annual dose of the study subjects, 15 people (37.5%) than the 1 mSv dose distribution and 5 people (12.5%) and 1.01~5.0 mSv with the dose distribution was less than, 5.01~10.0 mSv in the 14 people (35.0%), 10.01~20.0 mSv in the 6 people (15.0%) of the distribution were analyzed. The average annual dose according to age in occupations that radiological workers 25~34 years old have the highest average of 8.69 mSv dose showed the average annual dose of tenure of 5~9 years in jobs radiation workers in the 9.5 mSv The average was the highest dose. Conclusion: These results suggest that medical radiation workers working in Nuclear Medicine radiation safety management of the majority of the current were carried out in the effectiveness, depending on job characteristics has been found that many differences. However, this requires efforts to minimize radiation exposure, and systematic training for them and for reasonable radiation exposure management system is needed.