핵의학 PET/CT의 임상적용

박훈희 대한전자공학회 2018 전자공학회지 Vol.45 No.3

An Initial Study on the Reliability Assurance in PET/CT Standardized Uptake Values

박훈희,김정열,이승재,박민수,남궁혁,임한상,오기백,김재삼,이창호,진계환,Park, Hoon-Hee,Kim, Jung-Yul,Lee, Seung-Jae,Park, Min-Soo,NamKoong, Hyuk,Lim, Han-Sang,Oh, Ki-Baek,Kim, Jae-Sam,Lee, Chang-Ho,Jin, Gye-Hwan The Korean Society of Nuclear Medicine Technology 2009 핵의학 기술 Vol.13 No.3

최근 PET/CT가 급격하게 증가하면서 의료기관 사이에 영상의 이동도 증가하고 있다. 이에 서로 다른 의료기관 간의 시스템 별 표준섭취계수 차이를 반영하기 위하여 1 Bed에서 표준섭취계수, 슬라이스 내의 표준섭취계수 변화율과 측정시간에 따른 표준섭취계수를 정량적으로 비교할 수 있는 팬텀을 이용한 비교측정이 필요하다. 본 연구에서는 임상에서 사용하는 다양한 PET/CT 시스템의 표준섭취계수 차이에 대한 연구를 통하여, PET/CT 영상의 표준화섭취계수의 신뢰성을 확보하고자 하였다. 대한민국 전국에 분포되어 의료기관에 설치된 PET/CT 장비 10대를 대상으로 하였으므로, 정확한 방사능 산출을 위하여, 한국표준과학원의 검출기로 검증을 통하여 실험하였다. NEMA PET $Phantom^{TM}$의 내부구조물을 제거하고 $^{18}F$-FDG 1 mCi를 6,000 mL 증류수에 균일하고 분포하도록 마그네틱 스터러와 마그네틱 바의 회전력으로 희석하여, 팬텀에 주입하였다. 주입 후 60분, 70분, 80분, 90분, 100분, 110분, 120분에 3분간 영상을 획득하고, 관심영역 $200\;cm^2$에 대하여 분석하였으며, 유용성 확인을 위하여 임상환자를 대상으로 교정표를 산출하였다. 1 Bed에서 표준섭취계수, 슬라이스 내의 표준섭취계수 변화율, 측정시간에 따른 표준 섭취계수 변화율과 함께 표준섭취계수의 변이계수가 -11.0~9.90%로 국제적으로 통용되는 기준인 ${\pm}10%$를 1개의 장비를 제외하고 모두 만족하였다. 또한, 시스템 별 평균 표준섭쉬계수 차이를 이용하여 0.803~1.246으로 이루어진 교정표를 도출하였고, 정상인을 통한 임상 적용에서 선형회귀분석을 통하여 유의함을 확인하였다. 본 연구를 통하여 PET/CT 장비간의 표준섭취계수 차이를 교정표를 이용하여 정량적으로 비교할 있는 근거를 제시한다면 정확한 진단에 도움이 되며, 아울러 이에 대한 세계적 기준이 명확하지 않기에 유사 연구에 도움이 되리라 사료된다. Purpose: As the number of domestic medical institutions installing PET/CT is increasing rapidly, the transfer of PET/CT images among medical institutions is also increasing. Thus, it is necessary to collect the comparative SUV data from several medical institutions' PET/CT systems through a phantom study which semi-quantitatively compares the SUV on one bed, the change scale of the SUV on the slices, and the time of measuring. The phantom study to find differences among the SUVs from various PET/CT offers the opportunity to obtain the reliability of the SUV in PET/CT images. Materials and Methods: Ten PET/CT systems from medical institutions in Korea were used. To obtain the accurate data, the study has been using the radiation detector of Korea Research Institute of Standards and Science to verify. The internal structures of NEMA $phantom^{TM}$ were removed and Six thousand milliliters of distilled water which has 1mCi of $^{18}F$-FDG put into the phantom. The water was properly integrated with $^{18}F$-FDG using magnetic stirrer. The images were acquired at 60, 70, 80, 90, 100, 110 and 120-minutes for 3 minute each. Two hundred square centimeters of region of interests were placed and analyzed. To confirm the usefulness, the correction-table came out from patients' data. Results: The coefficient of variability of the SUV from -11.0 to 9.90 % fell into the range of international standards(${\pm}10%$) along with the SUV on a bed, the change scale of the SUV on the slices, and the time of measuring, except one PET/CT system. Using the data of the differences among the SUVs, we came to withdraw the correction-table ranging from 0.803 to 1.246. The correction-table was confirmed its usefulness through Linear Regression Analysis which was applied to normal cases. Conclusions: Although studies have been made on the variation of the SUV, there is little attention on the standardization of the SUV. Based on this study of the quantitatively comparable data about the SUV accommodating the correction-table, it would help to have more corrective diagnosis.

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.

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.

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 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.

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.

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.

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

3D 프린팅 팬텀의 핵의학분야 적용 평가 - 감마카메라 중심으로

박훈희,이주영,김지현,Park, Hoon-Hee,Lee, Juyoung,Kim, Ji-Hyeon 대한핵의학기술학회 2017 핵의학 기술 Vol.21 No.2

Purpose 3D 프린팅 기술은 3D 스캔이나 모델링을 통하여 적측가공 방식으로 제작하는 기공기술로서 금형 없이 직접 생산이 가능하고 빠른 시간 내에 제작이 가능하여 최근 다양한 산업분야에서 본격적으로 적용되고 있다. 3D 프린팅 기술은 의료분야에 있어, 영상의학 및 방사선 치료분야에서 다양하게 활용되고 있지만 핵의학 분야에서는 관련 연구가 미비한 실정이다. 그러므로 본 연구는 기존에 적용되고 있는 핵의학분야 팬텀과 3D 프린팅 기술로 제작된 텀의 특성을 비교하고 적용 가능성을 평가하는데 목적을 두었다. Materials and Methods 방사선 투과도 변화측정 국제기준 팬텀인 알루미늄(Aluminum) 계단 쐐기(step wedge)를 기준($140mm{\times}62mm{\times}35mm$)으로 PMMA(Poly Methyl Meta Acrylate)와 ABS(Acrylonitrile Butadiene Styrene)재질로 각각 동일한 크기의 팬텀을 제작하였다. PMMA 팬텀은 핵의학 분야에서 주로 적용되는 팬텀의 성분과 동일한 소재로 제작하였고, ABS 팬텀 제작은 3D 프린팅 기술의 액체 기반형의 SLA(Stereo Lithography Apparatus)기법을 사용하여 제작하였다. 본 연구는 SPECT/CT장비 BrightView XCT(Philips Health Care, Cleveland, USA)를 이용하였다. 영상 획득은 Rectangular Flood phantom(Biodex, New York, USA) $^{99m}TcO_4$ 3, 6 mCi와 $^{57}Co$ lood phantom(adqual, New Hampshire, USA) $^{57}Co$ 20 mCi를 이용하여 Aluminum, PMMA, ABS 팬텀에 대해 60 min 리스트모드(List mode)로 획득하였다. 획득한 영상의 분석을 위해 관심영역(ROI)을 설정하여 각 팬텀의 단계별로 평가하였다. Results 방사선원의 종류 및 방사선량에 따라 ABS 팬텀의 계수치는 PMMA 팬텀의 계수치와 유사한 값을 나타내며, 두께의 증가에 따라 선형적으로 감소하였다. Aluminum, PMMA, ABS 팬텀의 선감약계수를 비교했을 때, Aluminum 팬텀의 선감약계수는 나머지 두 팬텀보다 수치가 높았고, PMMA, ABS 팬텀에서는 근사치의 선감약계수가 나타났다. Conclusion 3D 프린팅 기술로 제작된 ABS 팬텀을 기준으로 PMMA 팬텀은 두께가 증가함에 따른 계수치의 변화가 유사하게 선형적으로 감소하였고, 선감약계수도 근사치로 나타내었다. ABS 팬텀의 핵의학적 적용 가능성을 확인할 수 있었으며, 추후 연구를 통해 세부적인 교정치(correction value)를 적용한다면 활발한 적용이 가능하리라 사료된다.