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이온전리함 기반의 컨테이너 검색용 고에너지 X-선 선량 측정장치 개발
이정희,임창휘,박종원,이상헌,Lee, Junghee,Lim, Chang Hwy,Park, Jong-Won,Lee, Sang Heon 한국정보통신학회 2020 한국정보통신학회논문지 Vol.24 No.12
X-ray of up to 9MeV are used for container inspection. X-ray intensity must be maintained stably regardless of changes in time. If dose is not constant, it may affect the image quality, and as a result, may affect the inspection of abnormal cargo. Therefore, to acquire high-quality images, continuous dose monitoring is required. In this study, the ion-chamber based device was developed for monitoring the dose change in high-energy x-ray. And to estimate the performance of signal-processing device change according to the environmental change, the output changing due to the change of temperature and humidity was observed. In addition, verification of the device was performed by measuring the output change. As a result of the measurement, there was no significant difference in performance due to changes in temperature and humidity, and the change in output according to the change in exposure was linear. Therefore, it was found that the developed device is suitable for the dose monitoring of high-energy x-ray. 일반적으로 컨테이너 내부검사를 위해서는 최대 9MeV의 X-선을 사용한다. 이때 사용되는 X-선은 선형가속기를 통해 생성되며 일정한 세기의 X-선량이 시간의 변화에 관계없이 안정적으로 유지되어야 한다. 만약 발생되는 X-선의 세기가 일정하지 않다면 영상의 해상도와 대비도 등에 영향을 미칠 수 있으며 결과적으로 컨테이너 내부의 이상화물에 대한 검사에 영향을 미칠 수 있다. 그러므로 고화질의 영상을 획득하기 위해서는 발생되는 X-선 선량에 대한 지속적인 모니터링이 요구된다. 이와같은 선량 모니터링을 위하여, 본 연구에서는 고에너지 X-선 선량의 변화 측정을 위한 이온전리함 기반의 선량변화 측정장치를 개발하였고 환경변화에 따른 신호처리부의 성능변화를 확인하기 위하여 온도와 습도 변화에 의한 측정값의 변화를 관찰하였다. 또한, 고에너지 X-선 발생장치에서 발생되는 선량의 변화에 따른 응답특성변화를 측정함으로써 개발한 X-선 선량측정장치의 검증을 수행하였다. 측정결과 온도와 습도의 변화에 따른 성능의 차이가 크게 나타나지 않았으며 입사되는 선량의 변화에 따른 출력의 변화가 선형적이었다. 그러므로 개발한 이온전리함 기반의 선량변화측정장치는 고에너지 X-선의 선량변화의 측정에 적용하기에 적합함을 알 수 있었다.
안면부 종창을 동반한 Henoch-Scho¨nlein 자반증 1례
이재휘,서무규,임문환,박성기,김태우,이창연 동국대학교 경주대학 1991 東國論集 Vol.10 No.-
We experienced a case of Henoch-Scho‥nlein purpura with are manifestation of facial swelling in a 7-year-old boy.
박민경,서원석,박재옥,김창휘,고은석,임철완 순천향의학연구소 2004 Journal of Soonchunhyang Medical Science Vol.10 No.2
Tuberculous peritonitis is discovered from sixty to ninty percent of pulmonary tuberculosis patients. Clinical symptoms are nonspecific such as mild fever, weakness and malaise but show tenderness in right lower abdomen and abdominal distension. Diagnosis is confirmed by laparoscopic and pathologic findings. We report a case of tuberculous peritonitis in an 11-year-old boy who was hospitalized because of abdominal distension with pain on right lower abdomen which had developed one day before he came to hospital. Chest X-ray showed pleural effusion on both sides. We did laparoscopic examination and observed diffuse nodular infiltration. In biopsy specimen we observed osseous granuloma and acid-fast bacilli in AFB stain.
박현종 ( Hyun Jong Park ),이문휘 ( Mun Hwi Lee ),문영진 ( Young Jin Moon ),임기은 ( Ki Eun Lim ),하창원 ( Chang Won Ha ),권자영 ( Ja Young Kwon ),박용원 ( Yong Won Park ) 대한주산의학회 2009 Perinatology Vol.20 No.4
Hydatidiform mole with a coexisting fetus is rare, but this condition has recently shown an increased incidence because of assisted reproduction technology. In most of the reported cases, termination at diagnosis was preferred due to poor fetal survival and maternal risk factors such as vaginal bleeding, preeclampsia, hyperthyroidism, potential of malignant change. However, considering the value of pregnancy by assisted reproduction technology, whether to continue or to terminate this condition is a dilemma. Based on currently available information, it seems that it is reasonable to allow the pregnancy to continue in the absence of maternal complications. We report on a case of the complete hydatidiform mole with two coexisting fetuses with a brief reviews of the literature.
프로토 타입 조직등가비례계수기의 중입자가속기연구소의 135 MeV/u 탄소 이온에 대한 선형에너지 스펙트럼 측정
남욱원 ( Uk Won Nam ),이재진 ( Jae Jin Lee ),표정현 ( Jeong Hyun Pyo ),박원기 ( Won Kee Park ),문봉곤 ( Bong Kon Moon ),임창휘 ( Chang Hwy Lim2,),문명국 ( Myung Kook Moon ),하시시키다무라 ( Hisashi Kitamure ),신고고바야시 ( Shingo Kob 한국센서학회 2014 센서학회지 Vol.23 No.3
TEPC (Tissue Equivalent Proportional Counter) was usually used for high LET radiation dosimetry. We developed a prototype TEPC for micro-dosimetry in the range of 0.2~300 keV/μm. And, the simulated site diameter of the TEPC is 2 μm, of similar size to a cell nucleus. For purposes of characterization the response for high LET radiation of the TEPC has been investigated under 135MeV/u Carbon ions in HIMAC (Heavy Ion Medical Accelerator). We determined the gas multiplication factor and measured the lineal energy spectrum [yd(y)] of 135 MeV/u Carbon ions. The value of the gas multiplication factor was 315 at 700 V bias voltage. As a result of the experiment, we could more understand the performance of the TEPC for high LET (Linear Energy Transfer) radiation. And the procedure of high LET radiation dosimetry using TEPC is established.
임창휘(Chang Hwy Lim),조민국(Min Kook Cho),한종철(Jong Chul Han),윤한빈(Hanbean Youn),윤승만(Seungman Yun),정민호(Min Ho Cheong),김호경(Ho Kyung Kim) 한국비파괴검사학회 2009 한국비파괴검사학회지 Vol.29 No.4
원추형 빔 단층촬영 시스템의 효과적인 모사를 위하여 상용 몬테칼로 코드인 MCNP를 기반으로 한 전산모사 시뮬레이터를 개발하였다. 기본적으로 Visual C++<SUP>®</SUP>를 이용하여 제작하였으며, 모델의 시각화를 위해 OpenGL<SUP>®</SUP> 라이브러리를 이용하여 개발하였다. 컴퓨터 단층촬영 시뮬레이션 수행을 위한 입력파일의 생성과 MCNP를 이용한 시뮬레이션 실행, 그리고 투과영상 생성과 단층영상 재구성을 수행할 수 있는 기능을 구현하였다. 개발한 시뮬레이터의 검증을 위하여 콘트라스트 팬텀(contrast phantom)에 대해 실험과 시뮬레이션을 수행하였다. 산란 엑스선, 영상센서의 잡음 및 픽셀 결함에 의한 structured noise 등을 시뮬레이션에서 고려하지 못했기 때문에 두 결과가 정확하게 일치하지는 않았으나, 매우 유사한 비교 결과를 얻을 수 있었다. 본 연구를 통해 개발한 MCNP 기반의 CBCT 전산모사 시스템은 CBCT의 이해, 실제 시스템의 설계 및 제작시에 도움을 줄 것으로 기대된다. We have developed a computer simulator for cone-beam computed tomography (CBCT) based on the commercial Monte Carlo code, MCNP. All the functions to generate input files, run MCNP, convert output files to image data, reconstruct tomographs were realized in graphical user-interface form. The performance of the simulator was demonstrated by comparing with the experimental data. Although some discrepancies were observed due to the ignorance of the detailed physics in the simulation, such as scattered X-rays and noise in image sensors, the overall tendency was well agreed between the measured and simulated data. The developed simulator will be very useful for understanding the operation and the better design of CT systems.
고에너지 X-선 영상검출을 위한 CdWO<sub>4</sub> 섬광체 두께와 반사체의 반사율 변화에 따른 광 수집량의 변화
임창휘,박종원,이정희,Lim, Chang Hwy,Park, Jong-Won,Lee, Junghee 한국정보통신학회 2020 한국정보통신학회논문지 Vol.24 No.12
컨테이너 검색을 위해 사용되는 고에너지 X-선 영상획득용 검출기는 입사되는 고에너지 X-선을 효과적으로 획득하기 위하여 MeV X-선 수집이 충분히 수행될 수 있는 두께의 섬광체를 사용한다. 컨테이너 검색기에서는 섬광체에 입사되는 X-선의 에너지는 일반적으로 최대 9MeV의 X-선이 사용된다. 그러므로 고에너지 X-선 광자를 효과적으로 수집하기 위해서는 수 cm 두께의 섬광체가 이용되어야 하며 섬광체의 두께는 신호의 수집효율에 영향을 미치게 된다. 본 연구에서는 컨테이너 검색에 사용되는 CdWO4 섬광체와 소면적의 센서를 활용한 영상검출기의 설계조건에 대한 연구를 기술하고 있다. 이를 위하여 본연구에서는 섬광체의 적절한 두께와 섬광체 표면의 반사율에 따른 빛 수집효율을 계산하기 위하여 MCNP6와 DETECT2000을 활용하여 다양한 조건에서 X-선 거동과 빛의 거동에 대한 모사를 수행하였다. 빛 수집효율 계산결과 섬광체 표면의 반사율이 낮은 경우 대략 15 ~ 20mm 두께의 섬광체를 선정하는 것이 적합하였으나 반사율이 높아짐에 따라 대략 25 ~ 30mm 두께의 CdWO4 섬광체를 선정하는 것이 적합한 것으로 확인되었다. The high-energy X-ray imaging detector used for container inspection uses a thick scintillator to effectively acquire X-rays. X-ray incident on the scintillator is generally up to 9MeV. Therefore, to effectively collect X-ray, it is necessary to use a thick scintillator. To collect the light generated by the reaction between X-ray and scintillator, an optical-sensor must be combined with the scintillator. In this study, a study on the design conditions of the detector using a CdWO4 and a small sensor is described. To calculate the collected light according to the change of the scintillator thickness and the reflectance of surface, MCNP6 and DETECT2000 were used. As a result of calculating, it was confirmed that when the reflectance of the surface was low, it was appropriate to select a scintillator with a thickness of 15 to 20-mm, but as the reflectance increased, it was confirmed that it was appropriate to select a CdWO4 with a thickness of 25 to 30-mm.
Lee, Jeonghee,Lim, Chang Hwy,Park, Jong-Won,Kim, Ik-Hyun,Moon, Myung Kook,Lim, Yong-Kon The Korean Association for Radiation Protection 2017 방사선방어학회지 Vol.42 No.4
Background: X-ray imaging detectors for the nondestructive cargo container inspection using MeV-energy X-rays should accurately portray the internal structure of the irradiated container. Internal and external factors can cause noise, affecting image quality, and scattered radiation is the greatest source of noise. To obtain a high-performance transmission image, the influence of scattered radiation must be minimized, and this can be accomplished through several methods. The scatter rejection method using an anti-scatter grid is the preferred method to reduce the impact of scattered radiation. In this paper, we present an evaluation the characteristics of the signal and noise according to physical and material changes in the anti-scatter grid of the imaging detector used in cargo container scanners. Materials and Methods: We evaluated the characteristics of the signal and noise according to changes in the grid ratio and the material of the anti-scatter grid in an X-ray image detector using MCNP6. The grid was composed of iron, lead, or tungsten, and the grid ratio was set to 2.5, 12.5, 25, or 37.5. X-ray spectrum sources for simulation were generated by 6- and 9-MeV electron impacts on the tungsten target using MCNP6. The object in the simulation was designed using metallic material of various thicknesses inside the steel container. Using the results of the computational simulation, we calculated the change in the scatter-to-primary ratio and the signal-to-noise ratio improvement factor according to the grid ratio and the grid material, respectively. Results and Discussion: Changing the grid ratios of the anti-scatter grid and the grid material decreased the scatter linearly, affecting the signal-to-noise ratio. Conclusion: The grid ratio and material of the anti-scatter grid affected the response characteristics of a container scanner using high-energy X-rays, but to a minimal extent; thus, it may not be practically effective to incorporate anti-scatter grids into container scanners.