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.

새로 개발된 국산 니티놀 담도스텐트의 유효성 평가 : 물리적 특성 시험

박훈희,김태형,김종규,임진오,최원찬,이세철,장용철,류명선 대한방사선사협회 2002 대한방사선사협회지 Vol.28 No.1

A Study of Decrease Exposure Dose for the Radiotechnologist in PET/CT

박훈희,김빛나,조석원,이주영,유광열 대한방사선과학회 2015 방사선기술과학 Vol.38 No.1

Positron emission tomography scan has been growing diagnostic equipment in the development of medical imaging system. Compare to 99mTc emitting 140 keV, Positron emission radionuclide emits 511 keV gamma rays. Because of this high energy, it needs to reduce radioactive emitting from patients for radio technologist. We searched the external dose rates by changing distance from patients and measure the external dose rates when we used shielder investigate change external dose rates. In this study, the external dose distribution were analyzed in order to help managing radiation protection of radio technologists. Ten patients were searched (mean age: 47.7 ± 6.6, mean height: 165.5 ± 3.8 cm, mean weight: 65.9 ± 1.4 kg). Radiation was measured on the location of head, chest, abdomen, knees and toes at the distance of 10, 50, 100, 150, and 200 cm, respectively. Then, all the procedure was given with a portable radiation shielding on the location of head, chest, and abdomen at the distance of 100, 150, and 200 cm and transmittance was calculated.In 10 cm, head (105.40 μSv/h) was the highest and foot(15.85 μSv/h) was the lowest. In 200 cm, head, chest, and abdomen showed similar. On head, the measured dose rates were 9.56 µSv/h, 5.23 µSv/h, and 3.40 µSv/h in 100, 150, and 200 cm, respectively. When using shielder, it shows 2.24 µSv/h, 1.67 µSv/h, and 1.27 µSv/h in 100, 150, and 200 cm on head. On chest, the measured dose rates were 8.54 µSv/h, 4.90 µSv/h, 3.44 µSv/h in 100, 150, and 200 cm, respectively. When using shielder, it shows 2.27 µSv/h, 1.34 µSv/h, and 1.13 µSv/h in 100, 150, and 200 cm on chest. On abdomen, the measured dose rates were 9.83 µSv/h, 5.15 µSv/h, and 3.18 µSv/h in 100, 150, and 200 cm, respectively. When using shielder, it shows 2.60 µSv/h, 1.75 µSv/h, and 1.23 µSv/h in 100, 150, and 200 cm on abdomen. Transmittance was increased as the distance was expanded.As the distance was further, the radiation dose were reduced. When using shielder, the dose were reduced as one-forth of without shielder. The Radio technologists are exposed of radioactivity and there were limitations on re-ducing the distance with Therefore, the proper shielding will be able to decrease radiation dose to the technologists.

비스무스, 텅스텐 기반 차폐체의 성능 및 유용성 평가

박훈희 대한방사선과학회 2018 방사선기술과학 Vol.41 No.6

Lead apron is harmful to the human body because it is made at heavy metals, and when worn for long periods of time, it causes pain. Therefore, this paper intended to improve the defects of lead apron by using new material shields. For the comparative evaluation of lead and new material shieldes, the shielding rate and weight were measured and tested based on lead 0.5 mmPb. The rate of shielding was 97% based on lead at 0.5 ㎜ thickness, while The new material shield T3 showed similar shielding rates as lead in 8 layers, and in T2 these values were measured in 11 layers. In addition, similar shielding rate was measured in 12 layers at B2, and 8 layers in BF, and 4 layers in BF2. Comparing the weight of cases when commercialized with apron, T3, T2 and B2 were heavier than lead apron. But BF, BF2 were lighter than the lead apron. Based on the results of the experiment, T3 and T2 can be used as an alternative to lead if human or environmental hazards are considered a priority. However, BF and BF2 should be used if the reduction of external exposure is considered a priority.

A Study of the Changes of Breast Uptakein Menstrual Cycle on 18F-FDG PET/CT

박훈희,탁여진,박민수,이주영 대한방사선과학회 2015 방사선기술과학 Vol.38 No.1

18F-FDG PET/CT has been known a useful modality to diagnose high-glucose-using cells such as cancer cells by glucose metabolism of FDG. Mainly, FDG takes on cancer and inflammatory cells; however, there have been FDG uptakes on normal tissues by individual physiological characteristics, occasionally. Especially, in fertile fe-males, unusual FDG uptake of breast changes as the menstrual cycle, and disturb diagnosis. Therefore, the study aimed to evaluate the change of breast FDG uptake in menstrual cycle on 18F-FDG PET/CT. 160 females (34±3.5 years old) who do not undergo a gynecologic anamnesis and have regular menstrual cycle over the previous 6 months were examined. They were divided 4 groups (each 40 patients) as flow phase, proliferative phase, ov-ulatory phase and secretory phase using Pregnancy Calculator 0.14. and history taking. Discovery Ste (GE Healthcare, Milwaukee, Mi, USA) was used as PET/CT. We analyzed SUVs on accumulated region on breast, and 3 nuclear medicine specialists did the Blind test. SUVs on the Breast were flow phase (1.64±0.25), proliferative phase (0.93±0.28), ovulatory phase (1.66±0.26) and secretory phase (1.77±0.28). It showed high uptake value in secretory, flow phase and ovulatory phase (p<0.05). In gross analysis, the accumulation of breast was divided in-to 3 grades as comparing with lung and liver. The breast’s uptake was equal to lung (Grade Ⅰ); between lung and liver (Grade II); equal to or greater than liver (Grade III). The results showed high uptake value in secre-tory, flow phase and ovulatory phase (p<0.05). In fertile females, FDG uptake of breast changed as menstrual cycle, and it available to diagnose breast disease. Therefore, we consider reducing false-negative finding of breast disease, by doing examination on appropriate period through history taking about individual menstrual cycle.

3D 프린팅 기법 기반의 Hoffman Brain 팬텀 개발 및 유용성 평가

박훈희,이주영 대한방사선과학회 2019 방사선기술과학 Vol.42 No.6

The purpose of this paper is to recognize the usefulness of the Phantom produced with 3D printing technology by reproducing the original phantom with 3D printing technology. Using CT, we obtained information from the original phantom. The acquired file was printed by the SLA method of ABS materials. For inspection, SPECT/CT was used to obtain images. We filled the both Phantom with a solution mixed with 99mTcO4 1 mCi i n 1 liter of water a nd acq uired images in accordance with the standard protocol. Using Image J, the SNR for each slice of the image was obtained. As a reference images, AC images were used. For the analysis of acquired images, ROI was set in the White mater and Gray mater sections of each image, and the average Intensity Value within the ROI were compared. According to the results of this study, 3D printed phantom's SNR is about 0.1 higher than the conventional phantom. And the ratio of Intensity Value was shown in the original 1 : 3.4, and the printed phantom was shown to be 1 : 3.2. Therefore, if Calibration Value is applied, It is assumed that it can be used as an alternative to the original.

방사선과 재학생의 수시출입자 방사선 피폭선량에 대한 고찰

박훈희 대한방사선과학회 2018 방사선기술과학 Vol.41 No.6

The Nuclear Safety Commission amended the Nuclear Safety Act by strengthening the safety management system for the frequent workers to the level of radiation workers. And students entering radiation management zones for testing and practical purposes are subject to frequent workers. It is inevitable that this will incur additional costs. In this paper, the validity of the amendment to the Nuclear Safety Act was to be assessed in terms of radiation protection. Study subjects are from 2014 to 2016, among university students in Seong-nam Korea and comparisons for analyses were made taking into account variables that are differences in annual, practical types, on-class and clinical practice students exposure dose. The analysis showed that exposures between on-class and clinical practice received were less than the annual dose limit of 1 mSv for the public. Then, some alternatives that excluding from frequent workers during on-class practice or mitigating the frequent workers’ safety regulation for only on-class frequent workers can be considered. Optimization is how rational is the reduction in exposure dose to the costs required. Therefore, the results are hardly considered for optimization. If the data accumulated, it could be considered that the revision of the act could be evaluated and improved.

핵의학 PET/CT의 임상적용

박훈희 대한전자공학회 2018 전자공학회지 Vol.45 No.3

PET/CT 영상에서의 표준섭취계수(SUV)의 신뢰성 확보를 위한 시스템별 차이에 관한 연구 : 초기 연구

박훈희,박민수,김정열,이승재,신희순,임한상,김세영,장혜원,오기백,김재삼,이창호,Park, Hoon-Hee,Park, Min-Soo,Kim, Jung-Yul,Lee, Seung-Jae,Sheen, Hee-Soon,Lim, Han-Sang,Kim, Sei-Young,Jang, Hye-Won,Oh, Ki-Back,Kim, Jae-Sam,Lee, Chang-Ho 대한디지털의료영상학회 2008 대한디지털의료영상학회논문지 Vol.10 No.1

In this study, using an experiment, in certified an error between each system of SUV (standardized uptake value) that is one of the main analyses to diagnose a tumor in PET/CT, so, it would assure reliability and help to diagnose any lesions accurately. That is, a detailed analysis progressed. as all images reconstructed every setting time, then, clinical reliability between each system was expressed numerically at MBq/mL and SUV. Therefore, this study is considered that flexibility of follow-up using diverse system was insured, and it helps to offer accurate and beneficial information for diagnosis of various fields.

유방암 PET-CT 검사에서 Prone(복와위)자세의 유용성 평가

박훈희,김세영,김정열,박민수,임한상,정석,강천구,김재삼,이창호,Park, Hoon-Hee,Kim, Sei-Yung,Kim, Jung-Yul,Park, Min-Soo,Lim, Han-Snag,Jung, Suk,Kang, Chun-Goo,Kim, Jae-Sam,Lee, Chang-Ho,Lee, Yung-Joo 대한핵의학기술학회 2008 핵의학 기술 Vol.12 No.1

유방암은 FDG PET-CT에서 예민도는 80~96%, 특이도는 75~95% 정도이며, 유방촬영(mammography) 소견상 판단이 어려운 수진자에게 매우 유용하며, 검진으로서의 조기 암 검출을 충분히 기대할 수 있다. PET-CT에서 대부분의 검사는 앙와위(supine position)으로 검사되어 전신검사(whole body scan)에서 원형으로부터 변형된 유방영상을 획득된다. 반면에 보정구를 이용하여 복와위(prone position)으로 영상을 획득할 경우, 유방을 중력에 의존하여 보다 원형에 가깝게 표현함으로써 영상의 진단가치를 높일 수 있기에 그 유용성을 평가하였다. 유방암으로 의심되거나 확진 된 여성 환자 30명을 대상으로 하였으며, $^{18}F$-FDG 주사한 뒤 60분 후 supine position으로 whole body PET-CT scan 시행 후, 보정구를 이용하여 prone position으로 병변에 대한 추가검사(lesional scan)를 시행하였다. 각각 획득된 영상은 핵의학과 의사로부터 blind test를 하였고, PET-CT 영상의 SUV를 측정하여 분석하였다. 30명 중 27명의 환자에게서 prone자세가 진단 용이성과 정확한 판별률이 높았으며, 나머지 3명의 경우는 병소가 1 cm 이하의 크기로 인하여, MRI상에는 나타났지만 PET-CT에서는 진단에 의미있는 관찰을 할 수 없었다. supine position과 비교하여 prone position은 구조물의 중력에 의한 변형수치가 낮아, 병변의 구별이 곤란한 경우 명확하게 감별되었다. 각 자세에서 SUV분석은 유의수준 0.004로 유의하였다. Supine position을 통한 PET-CT 전신검사 후의 보정구를 이용한 prone position로 병변에 대한 lesional scan은 두 자세의 비교가 모두 가능하였으며, 경우에 따라 결정적으로 진단에 영향을 주었다. 두 가지 자세의 영상비교에 있어 prone position이 원발성(primary) 병변의 진단은 물론, 미세전이(micrometastasis)의 검출이 가능하였다. 이러한 prone position을 기반으로 구조적인 문제를 정량적 분석과 함께 극복한다면 병변의 진단에 있어 보다 유용한 진단적 정보를 얻을 수 있으리라 사료된다. Purpose: In FDG-PET/CT of breast cancer, a sensitivity was 80~96% and a specificity was 75~95% commonly. It was valuable to identify a cancer in early stage been difficult in Mammography. Most of the PET/CT scans have been examined on supine position, so, the image of breast has been acquired by reconstructed whole body scan image. However, using prone position with a compensator, a shape of breast was reassembly shown to be real by gravity. Therefore, the purpose of this study was to evaluate diagnostic value of prone position in FDG PET-CT of breast cancer. Materials and Methods: 30 female patients with doubtful or positive breast cancer were examined. The PET-CT whole body scan was acquired at 60 minutes after $^{18}F$-FDG injection on Supine position. Then, regional breast spot scan was progressed on prone position using a compensator. Each image was evaluated by physicians blinded to patient's data, and statistical analysis did through SUVs measured in PET-CT images. Results: In 27 of 30 patients, prone position was shown accurate discrimination and diagnostic value, but in another 3 patients had a lesion 1cm below, PET-CT couldn't detect it, unlike MRI. Consequently, prone position distinguished a lesion better than Supine position, because of low degree of metamorphosis by gravity. The SUVs analysis of each position was significant (p value=0.004). Conclusion: In PET-CT of breast cancer, prone position could detect micrometastasis as well as primary lesion, better than supine position. Therefore, this study proposes that any technical change considered morphological feature like prone position can offer adequate and useful diagnostic information, together with complementary quantitative analysis.