Monte Carlo Design and Simulation of a Grid−type Multi−layer Pixel Collimator for Radiotherapy: Feasibility Study

윤도군,정주영,서태석 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.9

In order to confirm the possibility of field application of a different type collimator with a multileafcollimator (MLC), we constructed a grid-type multi-layer pixel collimator (GTPC) by using aMonte Carlo n-particle simulation (MCNPX). In this research, a number of factors related to theperformance of the GPTC were evaluated using simulated output data of a basic MLC model. Alayer was comprised of a 1024-pixel collimator (5.0 × 5.0 mm2) which could operate individually asa grid-type collimator (32 × 32). A 30-layer collimator was constructed for a specific portal formto pass radiation through the opening and closing of each pixel cover. The radiation attenuationlevel and the leakage were compared between the GTPC modality simulation and MLC modeling(tungsten, 17.50 g/cm3, 5.0 × 70.0 × 160.0 mm3) currently used for a radiation field. Comparisonsof the portal imaging, the lateral dose profile from a virtual water phantom, the dependence of theperformance on the increase in the number of layers, the radiation intensity modulation verification,and the geometric error between the GTPC and the MLC were done using the MCNPX simulationdata. From the simulation data, the intensity modulation of the GTPC showed a faster responsethan the MLC’s (29.6%). In addition, the agreement between the doses that should be delivered tothe target region was measured as 97.0%, and the GTPC system had an error below 0.01%, whichis identical to that of MLC. A Monte Carlo simulation of the GTPC could be useful for verificationof application possibilities. Because the line artifact is caused by the grid frame and the foldedcover, a lineal dose transfer type is chosen for the operation of this system. However, the result ofGTPC’s performance showed that the methods of effective intensity modulation and the specificgeometric beam shaping differed with the MLC modality.

한국 다사(茶史)의 一考察

尹道心(윤도심) 일본어문학회 2008 일본어문학 Vol.43 No.-

몬테카를로 전산모사를 이용한 다엽콜리메이터의 기본 모델링과 품질보증요소의 정량적 평가

윤도군,서태석 대한방사선방어학회 2013 대한방사선방어학회 학술발표회 논문요약집 Vol.2013 No.04

조선시대 차 문화의 일고찰

尹道心 한일일어일문학회 2008 한일어문논집 Vol.12 No.-

Trimethoprim-sulfamethoxazole에 대해 지연성 과민반응을 보인 환자에서 성공적인 급속 탈감작 치료 사례 1예

윤도란 ( Doran Yoon ),안홍근 ( Hongkeun Ahn ),김세용 ( Se Yong Kim ),황성준 ( Seong Jun Hwang ),박한기 ( Han Ki Park ),강혜련 ( Hye Ryun Kang ) 대한천식알레르기학회(구 대한알레르기학회) 2015 Allergy Asthma & Respiratory Disease Vol.3 No.2

Trimethoprim-sulfamethoxazole (TMP-SMX) is an antibiotic used for the treatment or prophylaxis of Pneumocystis pneumonia and other infectious conditions. Sulfonamide derivatives have been reported to cause delayed hypersensitivity reactions, resulting in switch to less effective second-line antibiotics. Although desensitization is traditionally known to be effective in patients with imme￢diate hypersensitivity, it is also applied to the treatment of delayed hypersensitivity in recent years. A 66-year-old female who had a history of repeated TMP-SMX-induced delayed hypersensitivity presenting as whole body rashes needed to take prophylactic dose of TMP-SMX (80/400 mg daily) before initiation of chemotherapy for multiple myeloma. Intravenous rapid desensitization was per￢formed by using a 11-step, 4-bottle protocol from 1:1,000 to 1:1 solution for 3 hours to reach the target dose for prophylaxis. After successful rapid desensitization of TMP-SMX, 1-month prophylaxis was completed without any complications until the patient re-covered normal immunity. We herein reported a case of delayed hypersensitivity reaction to TMP-SMX in an about-to-be immuno￢compromised host with planned chemotherapy who successfully completed 1-month prophylaxis with the drug without any com￢plications through rapid desensitization.(Allergy Asthma Respir Dis 2015;3:155-158)

한국의 다(茶) 문화 고찰

윤도심 일본어문학회 2010 일본어문학 Vol.49 No.-

茶人らが言う茶道とは人間の清浄心である。清浄心とは何事にも捕らわれない心を清浄心と言う。この心をもって、あるがままに自由にモノを見て、聞いて、味わい、触って全ての経験をしておいで。だけど、それに心奪われたりしちゃいけないよ。心を一ヶ所に停めてはだめですよ、という意味の禅語である。清浄心にあれば至る所に真理を見いだすことができる。花郎というのは、新羅時代に青年貴族から選ばれた夭き、みめよい戦士。美貌としなやかな身ごなしで、儒教․仏教․道教を融合した「風流道」の修行を積むため新羅の麗しい山河を駆けめぐった。もともと茶道は、上流社會で楽しむもので庶民生活とは程遠いものであったので、朝鮮王朝中期以降の茶文化は姿を潜め、僧やソンビなどがお茶をの嗜む程度となったが、いまから約30年前から再び茶文化が蘇り、大きく関心を惹くようになってきている。日本では、植物としての茶が伝来して栽培されるよりはるか以前、中国と韓半島に渡った僧侶たちにより、喫茶の習慣がもたらされ、禅宗寺院において茶禮として定着していった。

적층구조의 3차원 콜리메이터

윤도군(Dok-Un Yoon),이태웅(Tae-Woong Lee),이원호(Won-Ho Lee) 대한방사선과학회(구 대한방사선기술학회) 2013 방사선기술과학 Vol.36 No.2

2차원 방향으로 납을 이동하여 방사선 세기를 조절하는 기존의 다엽콜리메이터와는 다른 방식으로 고안 된 3차원 콜리메이터를 개발하였다. 3차원 콜리메이터는 복잡한 기하학적 구조에 방사선 조사에 있어 실시간으로 선량을 변화 할 수 있다. 3차원 콜리메이터는 정육면체 구조로 이를 구성하는 각각의 복셀화된 콜리메이터는 모터와 납으로 연결되어 있다. 각각의 프레임은 컴퓨터로 코딩된 FPGA 신호를 회로에 전달하여 계획대로 개별적으로 움직일 수 있다. 여러 가지 복잡한 기하학적 구조를 몬테칼로 시뮬레이션을 이용하여 결과를 도출하고 직접 실험한 결과를 비교 분석 하였다. Multileaf collimators whose Pb leaves are moving in two-dimensional directions have been used. We propose a different concept three-dimensional (3D) collimator with 3D shape that is automatically changeable to modulate the radiation dose even for complex tumors in real time. A voxel collimator, including a hinged Pb plane and a 3D assembly of many voxel collimators, was used. In each frame rotation axis, a motor, which was controlled by a circuit with field-programmable gate array (FPGA) board connected with computer, was operated according to a predetermined plan. Simulations of that, which are generally used for planning, were performed and compared with experimental results.

위치민감형 광다이오드 검출기의 신호처리회로 개발과 적용

윤도군(Do-kun Yoon),이원호(Won-ho Lee) 대한방사선과학회(구 대한방사선기술학회) 2012 방사선기술과학 Vol.35 No.4

본 연구는 위치 민감형 광 증폭 다이오드로부터 나오는 신호를 증폭 및 파형 변화 후 신호의 크기를 검출하여 일정시간 동안 유지시키는 뒷단 회로 개발에 관한 연구이다. 신호발생기에서 발생한 소신호를 증폭 소자를 통한 안정적인 증폭 후 미분회로를 통하여 신호 파형을 검출하기 수월한 형태로 변형 하고, peak/hold 회로에서 피크의 최대점을 일정시간 유지하여 신호의 수집을 원활하게 하였다. 본 회로에 대한 독립적인 성능 평가를 위하여 상용 장비로부터의 검사신호를 입력으로 사용하였다. The aim of this study was to develop a signal process circuit for a position sensitive avalanche photodiode detector. The circuit parts consisted of amplification, differential and peak/hold circuit. This research was the baseline to develop highly compact radiation detector. The signal was amplified by an amplification chip and its shape was changed in a differential circuit to minimize the pulse tailing. The peak/hold circuit detect the peak of the signal from the differential circuit and hold the amplitude of the peak for data acquisition. In order to test the intrinsic function of the circuit, the input signal was transmitted from a commercial pulse generator.

다국적 상품 웹 페이지의 표준화 정도에 관한 연구

박종민,윤도일,박병원 한국광고학회 2000 광고학연구 Vol.11 No.2

붕소 중성자 포획 치료에서 치료 영역 영상화를 위한 예비 연구

정주영,윤도군,한성민,장홍석,서태석,Jung, Joo-Young,Yoon, Do-Kun,Han, Seong-Min,Jang, HongSeok,Suh, Tae Suk 한국의학물리학회 2014 의학물리 Vol.25 No.3

본 연구의 목적은 붕소 중성자 포획 치료 시 집적된 붕소 영역에서 중성자 선속의 변화와 그에 따른 방출된 즉발 감마선의 검출 시뮬레이션을 통하여 치료 영역에 대한 영상화의 가능성을 확인하고자 함이다. 전산 모사를 통하여 (1) 붕소 유무에 따른 중성자의 영향, (2) 내부와 외부에서의 즉발 감마선량 검출, (3) 즉발 감마선에 대한 에너지 스펙트럼 검출을 수행하였다. 모든 전산 모사는 Monte Carlo n-particle extended (MCNPX, Ver.2.6.0, Los Alamos National Laboratory, Los Alamos, NM, USA)를 이용하여 가상의 물 팬텀과 열중성자(thermal neutron) 소스, 붕소 영역을 지정하였다. 열중성자의 에너지는 1 eV 이하의 에너지였으며 선속은 2,000,000 n/sec.로 설정하였다. 이 때, 발생된 즉발 감마선의 검출은 물 팬텀과 수직 방향으로 위치시키고 납으로 둘러싸인 lutetium-yttrium oxyorthosilicate (Lu0,6Y1,4Si0,5:Ce; LYSO) 섬광체 검출기를 이용하였다. 붕소가 존재하는 영역인 5 cm 깊이에서의 28 분할로서 대략 0.18 cm의 bin을 도출하여 붕소 영역의 얕은 깊이에서부터 급격하게 저하되는 것을 확인하였다. 또한 붕소 영역이 시작되는 지점인 9 cm 깊이에서 감마선의 피크 레벨을 확인하였다. 그리고 478 keV 지점에서 정확한 즉발 감마선 피크가 관찰되는 것을 확인하였다. 478 keV의 즉발 감마선 피크는 41 keV의 반치폭으로 에너지 분해능 값은 8.5%로 측정되었다. 결론적으로 붕소 중성자 포획 치료 시 발생되는 즉발 감마선의 계측으로 치료가 행해지는 부위를 감마 카메라 또는 단일 광자 방출 단층 촬영 기기에서 영상화할 수 있는 가능성을 확인하였다. The purpose of this study was to confirm the feasibility of imaging of therapy region from the boron neutron capture therapy (BNCT) using the measurement of the prompt gamma ray depending on the neutron flux. Through the Monte Carlo simulation, we performed the verification of physical phenomena from the BNCT; (1) the effects of neutron according to the existence of boron uptake region (BUR), (2) the internal and external measurement of prompt gamma ray dose, (3) the energy spectrum by the prompt gamma ray. All simulation results were deducted using the Monte Carlo n-particle extended (MCNPX, Ver.2.6.0, Los Alamos National Laboratory, Los Alamos, NM, USA) simulation tool. The virtual water phantom, thermal neutron source, and BURs were simulated using the MCNPX. The energy of the thermal neutron source was defined as below 1 eV with 2,000,000 n/sec flux. The prompt gamma ray was measured with the direction of beam path in the water phantom. The detector material was defined as the lutetium-yttrium oxyorthosilicate (Lu0,6Y1,4Si0,5:Ce; LYSO) scintillator with lead shielding for the collimation. The BUR's height was 5 cm with the 28 frames (bin: 0.18 cm) for the dose calculation. The neutron flux was decreased dramatically at the shallow region of BUR. In addition, the dose of prompt gamma ray was confirmed at the 9 cm depth from water surface, which is the start point of the BUR. In the energy spectrum, the prompt gamma ray peak of the 478 keV was appeared clearly with full width at half maximum (FWHM) of the 41 keV (energy resolution: 8.5%). In conclusion, the therapy region can be monitored by the gamma camera and single photon emission computed tomography (SPECT) using the measurement of the prompt gamma ray during the BNCT.