MPECVD에 의한 CO-H₂ 혼합 기체로 부터의 다이아몬드 합성에 관한 연구

具滋春(Ja-Chun Ku),吳政燮(Jung-Sub Oh),黃琪雄(Ki-Woong Whang) 대한전기학회 1990 전기학회논문지 Vol.39 No.6

전자 사이클로트론 공명 플라즈마 화학적 기상 증착 장치에서의 수소 플라즈마 특성연구

김우준(Woo-Jun Kim),구자춘(Ja-Chun Ku),황기웅(Ki-Woong Whang) 한국진공학회(ASCT) 1994 Applied Science and Convergence Technology Vol.3 No.3

Electron cyclotron resonance plasma chemical vapor deposition(ECRPCVD) 장치에서 공정변수에 따른 수소 플라즈마 특성을 조사하였다. 균일한 플라즈마 밀도를 얻기 위하여 전자공명층이기판과 평행하게 형성되도록 정자장 코일을 설계하였으며, 기판근처에 부가적으로 형성된 multicusp field에 의해서 기판 근처에서의 플라즈마 균일도를 개선시킬 수 있었다. 또한, 절연된 공진실과 기판에의 독립적인 DC bias에 의해서 기판으로 입사하는 하전입자들의 에너지와 유량을 조잘할 수 있었다. 이러한 플라즈마 특성을 갖는 ECRPCVD장치를 다양한 특성을 갖는 박막 합성에 응용할 수 있으리라 사료된다 The characteristics of the hydrogen plasma were investigated as functions of the process parameters in the electron cyclotron resonance plasma chemical vapor deposition(ECR-PCVD) system. The external magnet coils was designed such that ECR layer is parallel to the substrate to obtain a uniform plasma density, and the uniformity was improved by the additional multicusp field near the substrate. By the applications of independent DC biases to the cavity and the substrate, the energy and the flux of the charged particles in the plasma could be controlled. It is thought that this ECRPCVD system can be applied to the large and uniform coating having various properties.

방사선치료시 물리학적 반음영의 검토

김영범,황웅구,김유현,Kim, Young-Bum,Whang, Woong-Ku,Kim, You-Hyun 대한방사선치료학회 1994 大韓放射線治療技術學會誌 Vol.6 No.1

Proper evaluation about the penumbra is very important to improve the efficacy of radiation theraphy. There are two kinds of physical penumbra, geometric penumbra and transmission penumbra. In this study, we evaluated the variation of physical penumbra according to the varing enery level, changing the field size and depth. Physical penumbra width was decreased as the source size decreased, and as the SDD increased, but the consideration about the scatter radiation and mechanical stability is an important factor. For the two adjacent beams, upper collimator should be used and especially for Co-60 unit, it is efficient to use the extended collimator.

전자선 조사야 결합부분의 선량분포 개선을 위한 Acrylic Electron Wedge의 제작 및 사용

김영범,권영호,황웅구,김유현,Kim Young Bum,Kwon Young Ho,Whang Woong Ku,Kim You Hyun 대한방사선치료학회 1998 大韓放射線治療技術學會誌 Vol.10 No.1

Treatment of a large diseased area with electron often requires the use of two or more adjoining fields. In such cases, not only electron beam divergence and lateral scattering but also fields overlapping and separation may lead to significant dose inhomogeneities(${\pm}20\%$) at the field junction area. In this study, we made Acrylic Electron Wedges to improve dose homogeneities(${\pm}5\%$) in these junction areas and considered application it to clinical practices. All measurements were made using 6, 9, 12, 16, 20MeV Electron beams from a linear accelerator for a $10{\times}10cm$ field at 100cm SSD. Adding a 1 mm sheet of acryl gradually from 1 mm to 15 mm, We acquired central axis depth dose beam profile and isodose curves in water phantom. As a result, for all energies, the practical range was reduced by approximately the same distance as the thickness of the acryl insert, e.g. a 1 mm thick acryl insert reduce the practical range by approximately 1 mm. For every mm thickness of acryl inserted, the beam energy was reduced by approximately 0.2MeV. These effects were almost independent of beam energy and field size. The use of Acrylic Electron Wedges produced a small increase $(less\;than\;3\%)\;in\;the\;surface\;dose\;and\;a\;small\;Increase(less\;than\;1\%)$ in X-ray contamination. For acryl inserts, thickness of 3 mm or greater, the penumbra width increased nearly linear for all energies and isodose curves near the beam edge were nearly parallel with the incident beam direction, and penumbra width was $35\;mm{\sim}40\;mm$. We decide heel thickness and angle of the wedge at this point. These data provide the information necessary to design Acrylic Electron Wedge which can be use to improve dose uniformity at electron field junctions and it will be effectively applicated in clinical practices.

조사야 확인용 film을 이용한 자궁 경부암환자의 조사야 정확성 연구

김유현,정희영,권영호,정덕양,황웅구 高麗大學校 倂設 保健大學 保健科學硏究所 1995 保健科學論集 Vol.21 No.1

In order to help establish a baseline rate of field placement errors that may be expected in the delivery of radiation therapy and correlate these errors to anatomic regions and specific treament sites, the portal films were reviewed for 30 patients with uterine cervical cancer who were treated over 6 months period at Korea University Hospital Radiation Oncology Department. 30 patients were divided by 6 groups, 5 patients respectively : Group ① : Standard physique, supine not-fixed. Group ② : Standard physique, supine fixed. Group ③ : Obesity physique, supine not-fixed. Group ④ : Obesity physique, supine fixed. Group ⑤ : Obesity physique, prone not-fixed. Group ⑥ : Obesity physique, prone fixed. All groups were taken verification films during the whole treatment period, and it compared with simulation films and portal films. This results suggest that all patients should be immovilized and especially obesity phsique patients should be treated by prone postion in order to reduce radiation field discrepancy. In addition, this results should help to prescribe appropriate safty margins for patient simulation.

방사선 전신 조사 치료시 정확한 환자자세 및 조사야 재현을 위한 방법

권영호,이병구,황웅구,김유현,KWEON YOUNG-HO,LEE BYOUNG-GOO,WHANG WOONG-KU,KIM YOU-HYUN 대한방사선치료학회 1995 大韓放射線治療技術學會誌 Vol.7 No.1

방사선 전신조사는 일반적인 방사선 치료와는 달리 환자의 몸 전체를 포함할 수 있는 큰 조사야와 확장된 SAD가 요구되어지기 때문에 치료실이 충분히 커야 하고 전신에 균등한 선량을 주기 위해서는 환자 체표면 윤곽의 불규칙성과 조직 불균질성을 보완해 줄 수 있는 보상체가 필요하며 피부선량을 높여주기 위해서는 적절한 두께의 방사선 산란체를 사용하여야 한다. 또한 치료장치 및 사용 에너지, 총선량, 선량률, 선량분할, 환자의 자세, 정상적인 조직과 장기의 차폐 등도 방사선 전신조사를 위한 중요한 인자들로 알려져 있다. 그리고 방사선 전신조사 치료방법은 환자치료를 위한 준비시간과 실제 치료시간이 길기 때문에 일상 치료환자 일정에 지장을 초래할 수도 있으며 연속되는 치료기간 동안 치료조사야의 정확한 재현이 무엇보다 중요한 것으로 사료된다. 본원에서는 환자의 자세를 굴곡좌위로 함으로써 짧은 거리에서도 환자를 조사야내에 충분히 포함시켰고, 납 보상체를 제작하여 조직결손 부위를 보상하여 전신에 균등한 선량을 줄 수 있었으며 폐 차폐물을 제작하여 폐의 선량을 조절하였다. 치료계획시 환자의 음영을 치료실 벽면에 그려넣음으로써 조사야 재현시 도움이 되도록 하였으며 치료시간을 단축할 수 있었다. Total body irradiation (TBI) requires large radiation field and extended source to axis distance (SAD), therefore in needs large size treatment room and it needs compensators which components. Appropriate thickness beam spoiler should be used to raise skin dose. Treatment machine, photon energy, total dose, dose rate, dose fractionation, patient position, shield of normal tissues and organs were known to important parameters for TBI. TBI disturbes regular daily treatment schedule and significantly overloads Radiation on oncology departments and during the treatment session it requires accurate reproduction of radiation field and patient position. We were enable to TBI in small size treatment room and short SAD with parallel opposing lateral fields technique and achieved homogenious whole body dose distribution using pb compensators and controled lung dose by lung shield blocks. Drawing a patient shadow on the wall, we could shortened set up time and possible to accurate reproduction of radiation field and patient position.

조사야 확인용 film을 이용한 자궁 경부암 환자의 조사야 정확성 연구

정희영,권영호,정덕양,황웅구,김유현,Jung Hee-Young,Kweon Young-Ho,Jeong Deok-Yang,Whang Woong-Ku,Kim You-Hyun 대한방사선치료학회 1995 大韓放射線治療技術學會誌 Vol.7 No.1

1. Purpose : 30 patients with uterine cervical cancer who had been treated at Department of radiation Oncology of Korea university Hospital from June, 1, 1994. to December. 31, 1994. were analyzed to the radiation field accuracy using verification films. 2. Methods and Materials : 30 patients were divided by 6 groups, 5 patients respectively : Group (1) : Standard physique, supine not-fixed Group (2) : Standard physique, supine fixed Group (3) : Obesity physique, supine, not-fixed Group (4) : Obesity physique, supine, not-fixed Group (5) : Obesity physique, prone, not-fixed Group (6) : Obesity physique, prone, fixed All groups were taken verification fimls during the whole treatment period, and it compared with simulation films and portal fimls, 3. Results : This results suggest that all patients should be immovilized and especially obesity physique patients should be treated by prone position in order to reduce radiation field discrepancy. In addition, this results should help to prescribe appropriate safty margins for patients simulation.