Modeling of Dual Head Gantry Radiotherapy System with Monte Carlo Simulation

Seungwoo Park(박승우) 대한방사선과학회(구 대한방사선기술학회) 2017 방사선기술과학 Vol.40 No.4

듀얼 헤드 갠트리(dual-head) 갠트리 방사선치료 시스템을 설계하기 위해 LINAC의 단일 헤드는 GATE를 예비 연구로 사용하여 모델링되었다. LINAC 헤드는 임상에서 사용되고 있는 VARIAN사를 대상으로 모델링되었다. LINAC 헤드에서 생성된 6MV의 광자선을 물 팬텀에 조사하여 빔의 특성을 평가하였다. GATE 시뮬레 이션은 X- 선 스펙트럼을 생성한 후 물 팬텀에 광자선을 조사하였다. 결과로는 백분율 깊이 선량 과 빔의 프 로파일을 평가하였으며, 5 × 5와 10 × 10 ㎠에서 수행하였다. 빔 품질이 검증 된 후 듀얼 헤드 갠트리(dual head gantry) 방사선치료 시스템을 시뮬레이션 한 후 팬텀(phantom)을 이용한 선량 분포 측면에서 LINAC 시 스템의 단일 헤드와 비교하였다. 듀얼 헤드 갠트리 방사선치료 시스템은 단일 헤드 방사선치료 시스템에 비 해 방사선치료의 효율 면에서 40~60% 높은 것을 확인할 수 있었으며, 듀얼 헤드 방사선치료 시스템은 방사선치료 및 치료시간을 줄일 수 있을 것이 사료된다. In order to design a dual-head gantry radiotherapy system, the single head of LINAC was modeled using GATE as a preliminary study. The LINAC head was designed with VARIAN manufacturer’s information. 6 MV photons were generated from the head and the photons w irradiated to a water phantom for beam evaluation. GATE simulation was segmented by two stages, the one was to generate X-ray spectrum and the other one was for irradiation X-ray to the water phantom. The quantitative results were described in Percentage depth dose and beam profile. Two field size conditions were employed as 5 × 5 and 10 × 10 ㎠. After beam quality was verified, dual heads gantry radiotherapy system were simulated and they was compared to the single head of LINAC system in terms of dose deposition with in the phantom. The simulated LINAC head showed accept-able beam quality result for radiotherapy. The efficiency was calculated that deposited dose from dual heads was divided by the dose from single head. At all conditions, dual heads showed higher treatment efficiency. Efficiency was increased about 40 to 60%. Form the result, The dual head gantry system of new LINAC system will contribute to the practical radiotherapy of tumor and to reduce treatment time.

Hemorrhage 환자에 있어서 Dual-Energy Computed Tomography를 이용한 Head Angiography 검사의 유용성

정성민(Sung Min Chung),김혜진(Hye Jin Kim) 대한CT영상기술학회 2010 대한CT영상기술학회지 Vol.12 No.2

Purpose To estimate the availability of dual energy computed tomography(DECT) for the patients who had been underwent head angiography because of bleeding with the image(virtual non-contrast, VNC, 50% mixed image, overlay view) that was obtained by readjusting of iodine concentration at dual-energy processing and volume rendering image. Materials and methods The subjects were 40 patients who had hemorrhage or were suspected to have hemorrhage and took head angiography with DECT in our hospital from April 2009 to January 2010. The method was that we implemented the monitoring scan and set the interest area at aortic arch and made the scanning to be started automatically when Hounsfield unit reached to 100 using by auto bolus triggering. 60 ml of contrast medium was injected at the speed of 4 ml/sec and another 60 ml was injected at the speed of 2.5 ml/sec and 30 ml of saline was added at the speed of 2.5 cc/sec. The estimation was done with computed tomographic angiography(CTA) volume rendering images took from 3D reconstruction process and 2D mapping images(VNC 50% mixed image) took from dual console. Results We had 9 patients of Vascular lesion which was 25.5%, 16 patients of tumor lesion which was 40%, 8 patients of simple hemorrhage which was 20%, 4 patients who didn’t have hemorrhage which was 10%, 2 patients of tauma which was 5%, and 1 patient of hemorrhage caused by uncertain reason which was 2.5%. Conclusion It was concluded that the estimating the reason of hemorrhage using by both volume rendering image in bead angiography by dual energy and 2D mappiing image acquired through dual console can be an useful diagnosis to choose additional examinations and make a decision the direction of the treatment.

정상인에서 Dual-Head Gamma Camera를 이용한 위배출 연구

강영우(Young Woo Kang),손수호(Soo Ho Sohn),허정숙(Jung Sook Hur),박근용(Keun Young Park),안성훈(Sung Hoon Ahn),전석길(Seok Young Park) 대한소화기학회 1994 대한소화기학회지 Vol.26 No.2

N/A Gastric emptying study has an important role in patients with gastrointestinal functional disorders without demonstrable mechanical or mucosal abnormalities. Although several meth- ods for detection on gastrointestinal functional disorders are well known, non-invasive scintigraphic technique using a Gamma Camera is taken as a gold standard at present. A Dual-Head Gamma Camera coupled to a computer was used in 20 normal subjects after in- gestion of the mixture of ''T,-labelled scrambled egg in order to determine gastric emptying time. Four values including lag time, T,,(half gastric emptying time), remnant 1 hour, remant 2 hours were taken at all ages. In the female half gastric emptying time and lag time was slightly shorter, and the amount of remnant radioactive counts at one and two hours was smaller than the I,aale without significant difference. Delayed gastric emptying time was above 109. 9 minutes of half gastric emptying time when defined as excess of Mean+ZSD. W e believe this study using a Dual-Head Gamma Camera can be useful for establishment of more accurate gastric emptying study.(Korean J Gastroenterol 1994; 26: 2Z4 229)

한국어 이중 주격 구문의 유형과 통사 구조

박호관 우리말글학회 2004 우리말 글 Vol.31 No.-

The purpose of this paper is to look into the realization of dual-subjective construction of a sentence and then the syntactic structure by its type. The results of this study can be summarized as follows; First, though the realization of a dual-subjective construction sentence is made according to the morphology ‘-i(이)/ga(가)’, both of them can not be double subject constructions. Even though a dual-subjective is realized, the number of the subject of a sentence is one. And a realization of ‘-i(이)/-ga(가)’ of the existing-discussed morpho signs, a syntactic property, a semantic property can not be absolute criteria in confirmation of dual-subjective construction of a sentence, it should be discussed whether or not the formation of divided sentences which meets a syntax-semantic criterion can be made. Second, according to whether or not the composition of these divided sentences is possible, dual-subjective construction can be divided into three types: ① double subject constructions of deep structure such as “kkot-i jangmi-ga yeoppeu-da.(Flower, rose is beautiful.)” ; ② the subjective-ization construction of adverbial phrase such as “i kkot-i jangmi-ga pi-eot-da.(This flower, rose is in bloom.)” or “Yeonghui-ga don-i man-ta.(Yeonghui, money is abundant)” ; ③ the subjective-ization construction of genitive noun phrase such as “sagwa-ga se gae-ga sanghaet-da.(Apple, even three ones, is spoiled.)”, or “kokkiri-ga ko-ga gil-da.(Elephant, its tail, is long.)”. Third, the syntactic structure of dual-subjective construction can be generalized as shown in (26), head noun(N') of a noun phrase is selected in relation of a category and selection restrictions according to the value of argument in verb(V<s>'), and case marking(Ks) of noun phrase(NPs) is made according to the grammatical relation of verb(V<s>'), and head noun(N'). And when an another noun phrase is base-established on the position of specific(명시어), when a adverbial phrase is moved to specific position and precedes a subject noun phrase, or when a subjective noun phrase at the position of an internal or external complement is moved to the position of specific, subjective-marking(Ks) is permeated so that a dual-subjective construction can be realized.(Daegu University)

복수를 동반한 간경변증 환자에서 Dual - Head Gamma Camera 를 이용한 고형식의 위배출능 연구

손수호(Soo Ho Sohn),안성훈(Seong Hoon Ahn),강영우(Young Woo Kang) 대한내과학회 1994 대한내과학회지 Vol.47 No.4

N/A Objective: Various GI symptoms of the patient with liver disease can be related to gastrointestinal functional disorders without mechanical or mucosal abnormalities. We studied to evaluate the presence of delayed gastric emptying of solids which may be one of the causes of gastrointestinal dysfunction in patients with liver cirrhosis. Method: A Dual-Head Gamma Camera coupled to a computer was used in 20 normal volunteers and 12 patients with liver cirrhosis and GI-II ascites after ingestion of the mixture nf 99mTc-labelled scrambled egg in order to determine gastric emptying time. Results: Gastric lag time was 17.2 minutes in normal volunteers and 19.8 munutes in patients with liver cirrhosis, half gastric emptying time was 74.6 minutes in normal volunteers and 82.1 minutes in patients with liver cirrhosis. Although the patients with liver cirrhosis represented slightly delayed gastric emptying, there was no significant difference. The remnant radioactive count after one hour was 36100 in normal volunteers and 50200 in patients with liver cirrhosis, the remnant radioactive count after two hours was 15700 in normal volunteers and 29800 in patients with liver cirrhosis. Although the patients with liver cirrhosis represented high radioactive counts, there is was significant difference. Conclusions: As there is no definitely delayed gastric emptying of solids in patients with liver cirrhosis and ascites, it is needed to study in large numbers of patients and to evaluate other causes of gastrointestinal functional distrubance.

운동장애성 소회불량 환자에서 Dual - Head Gamma Camera 를 이용한 고형식의 위배출 연구

이운우(Woon Woo Lee),황재석(Jae Seok Hwang),강영우(Young Woo Kang) 대한내과학회 1995 대한내과학회지 Vol.49 No.6

N/A Objectives : The present study was performed to evaluate gastric emptying delay of solids using a dual-head gamma camera in patient with dysmotility-like functional dyspepsia. Methods: 75 patients with dysmotility-like functional dyspepsia and 30 healthy volunteers were studied gastric emptying of solids using a ADAC dual-head gamma camera. Results: The mean gastric emptying time (Tl/ 2) was 74.6±17.6 min in normal controls. Delayed gastric emptying defined as the time above 92.2 minutes, when it was defined as the value above mean+lSD of normal controls. There was no significant difference in gastric emptying time between dysmotility-like functional dyspepsia (66.9±19.6min) and normal cotrols(74.6±17.6min)(p>0,05), A gastric emptying delay was observed in 9% (7 cases) of 75 patients with dysmotility-like functional dyspepsia. Conclusion: The present study revealed a few incidence of delayed gastric emptying in patients with dysmotility-like functional dyspepsia, which resulted from a wide range of normal controls, and the need for study of gastrointestinal dysmotility and dysperception besides a gastric emptying delay.

Development of a Beam Source Modeling Approach to Calculate Head Scatter Factors for a 6 MV Unflattened Photon Beam

박소연,최누리,장나영 한국의학물리학회 2021 의학물리 Vol.32 No.4

Purpose: This study aimed to investigate the accuracy of head scatter factor (Sc) by applying a developed multi-leaf collimator (MLC) scatter source model for an unflattened photon beam. Methods: Sets of Sc values were measured for various jaw-defined square and rectangular fields and MLC-defined square fields for developing dual-source model (DSM) and MLC scatter model. A 6 MV unflattened photon beam has been used. Measurements were performed using a 0.125 cm3 cylindrical ionization chamber and a mini phantom. Then, the parameters of both models have been optimized, and Sc has been calculated. The DSM and MLC scatter models have been verified by comparing the calculated values to the three Sc set measurement values of the jaw-defined field and the two Sc set measurement values of MLC-defined fields used in the existing modeling, respectively. Results: For jaw-defined fields, the calculated Sc using the DSM was consistent with the measured Sc value. This demonstrates that the DSM was properly optimized and modeled for the measured values. For the MLC-defined fields, the accuracy between the calculated and measured Sc values with the addition of the MLC scatter source appeared to be high, but the only use of the DSM resulted in a significantly bigger differences. Conclusions: Both the DSM and MLC models could also be applied to an unflattened beam. When considering scattered radiation from the MLC by adding an MLC scatter source model, it showed a higher degree of agreement with the actual measured Sc value than when using only DSM in the same way as in previous studies.

이중각도 분사 방식에 의한 고효율 고압 믹싱 헤드 연구와 최적화

김슬기(S.G. Kim),전언찬(E. C. Jeon),하동승(D. S. Ha),박세종(S. J. Park),안광우(G. W. Ann),이찬우(C. W. Lee) (사)한국CDE학회 2015 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2015 No.동계

Video See-Through HMD를 위한 인터페이스 디자인 평가: 보행 중인 사용자 중심으로

신현주(Hyunjoo Shin),박재완(Jaewan Park) 한국디자인학회 2024 디자인학연구 Vol.37 No.1

Background : This study aims to evaluate the design of head-mounted display (HMD) interfaces in walking environments, focusing on the impact of interface position and opacity variations. Prior research on the subjective evaluation of mental load and satisfaction levels concerning opacity in dualtask situations like walking environments is limited and has primarily been conducted using optical seethrough (OST) methods. With the augmented reality HMD market shifting towards video see-through (VST) HMDs, research into VST HMD interfaces is becoming increasingly vital. Methods : We investigated how interface position and opacity affect user satisfaction and mental load in walking environments. A survey was conducted among 29 undergraduate and graduate students (17 males, 12 females) to measure satisfaction and mental load. Satisfaction was measured with a focus on the interface, while mental load evaluated the mental burden experienced by users while using the interface. Multivariate analysis of variance (MANOVA) was employed to assess differences in satisfaction and mental load based on position, opacity, and their interaction. Results : The results indicated that there were no statistically significant differences in satisfaction and mental load related to the position of the interface. However, there were statistically significant differences in satisfaction (66%=100%>33%) and mental load (66%<33%) related to opacity. No significant interaction was found between position and opacity. Conclusions : The study suggests that in designing VST HMD interfaces optimized for walking environments, both central and bottom positions can be flexibly chosen, and setting opacity to 66% can provide high satisfaction and low mental load. This research is significant in its exploration of ways to maximize satisfaction with interface attributes and to minimize mental load, thereby enhancing user experience. The study specifically focuses on the design of VST HMD applications considering walking environments. The results of this study can serve as foundational data for the design of VST HMD interfaces.

극소 공기막을 갖는 헤드 슬라이더 부상상태 해석

이상순,김광선,임경화 한국마이크로전자및패키징학회 2003 마이크로전자 및 패키징학회지 Vol.10 No.4

본 연구에서는 초고밀도 광디스크 시스템이나 하드 디스크 시스템의 헤드 슬라이더의 부상상태를 안정되고 효율적으로 예측하는 수치해석법을 다루고 있다. 뉴톤법과 유사 뉴톤법을 이용하여 정상적인 부상상태들을 예측하기 위해서 Dual Solver를 개발하였다. 수치해석 결과에 의하면, Dual Solver는 초고밀도 광디스크 시스템이나 하드 디스크 시스템용 슬라이더의 부상상태를 해석하는데 효과적이고 신뢰성있는 방법이 될 수 있다. A method that predicts the flying state of the head slider in an optical disk drive (ODD) or a hard disk drive(HDD) was investigated. The dual solver based on the Newton method and the quasi-Newton method have been developed to simulate the steady-state flying conditions. The numerical results show the effectiveness and reliability of this new solver.