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원판형 마이크로 히트 스프레더의 열성능에 대한 수치적 연구
신현교(Hyun Kyo Shin),이승현(Seung-Hyun Lee),장석필(Seok Pil Jang),김인철(In-Cheol Kim) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
The maximum heat transport rate of a disk-shaped micro heat spreader with pin-fin wick structure is numerically presented in this work. Using the conservative formulations for the steady incompressible vapor flow and the porous medium approach of liquid flow, the well-known Laplace-Young equation is solved to obtain the capillary radius. Based on the capillary radius, the maximum heat transport rate is calculated with the criterion of maximum capillary radius at condenser. Finally, the effects of porosity of wick structure, fin thickness, and height on maximum heat transport of a disk-shaped micro heat spreader are numerically suggested.
서현숙(Hyun Suk Suh),신현교(Hyun Kyo shin),이레나(Rena Lee) 대한방사선종양학회 2000 Radiation Oncology Journal Vol.18 No.4
목적 : 방사선조사야를 확인하는 보편적인 방법은 linacgram은 저대조도(low contrast)의 영상을 보여주고 있어 정확한 영상을 확인하는데 문제점이 있다. 따라서 본 연구는 linacgram의 대조도를 높이는 저가형 확인방법을 모색하여 영상판독과 조사야 확인에 도움이 되고자 한다. 대상 및 방법 : 인체모형을 사용하여 얻어진 필름 영상을 필름전용 스캐너(Diagnostic Pro)을 통해 Optical Density Scan, Histogram Equalized, Linear Histogram Based (HB), Linear Histogram Independent, Linear Optical Density (CD), Logarithmic 및 Power, Square Root scan 방식으로 디지털 화 하였다. 각기 다른 방식으로 전산 입력된 영상의 신호분포도를 얻어 signal intensity를 비교한 후 pallette fitting 방식을 통해 영상을 재구성하였고 재구성된 영상을 비교 분석하였다. 실제 치료에서 얻어진 각 인체 부위별 linacgram도 동일한 방법으로 처리한 후 화질 개선도를 알아 보았다. 결과 : 인체모형을 통해 얻어진 영상의 신호 분포영역은 Logarithmic 방식을 선택했을 때 최소값인 3192가 나왔고 Square Root방식을 사용했을 때 최대값인 21940가 나왔다. 이러한 값들을 모니터 상에서 구현할 수 있는 256 gray scale로 바꾸어 보았을 때 7~30%만 사용되어지고 있음을 알 수 있었다. Pallette fitting 방식을 통하여 모니터의 최대표현 값인 256 계조도로 Gray Scale Expansion (GSE) 함으로서 모니터가 지원하는 8bit gray scale pallette의 전 범위를 사용하여 대조도가 개선되었다. 임상에서 얻어진 각 인체 부위별 무릎관절, 두경부, 폐, 골반영상에서도 GSE 처리하여 얻어진 영상이 해부학적 구조를 판독하는데 도움이 되었다. 결론 : GSE 영상의 재구성은 대조도를 증가 시킬뿐 아니라 인체내 관심부위의 농도분포를 별도로 재구성할 수 있으므로 이중방사선조사(double exposure)에 의해 발생되는 화질의 저하를 보장함으로써 화질 개선을 가능하게 하였다. Linacgram 화질 개선은 simulation image 및 치료계획에서 발생한 DRR과 multi-layer 중첩영상 분석에 사용할 수 있으며 영상 비교 시 치료부위의 신속하고 정밀한 확인을 가능하게 하였다. Purpose : Conventional radiation therapy portal images gives low contrast images. The purpose of this study was to enhance image contrast of a linacgram by developing a low-cost image processing method. Materials and Methods : chest linacgram was obtained by irradiation humanold pahntom and scanned using Diagnostic-Pro scanner for image processing. Several types of scan method were used in scanning. These include optical density scan, histogram equalized scan, linear histogram based scan, linear histogram independent scan, linear optical density scan, logarithmic scan, and power square root scan. The histogram distribution of the scanned images were plotted and the ranges of the gray scale were compared among various scan types. The scanned images were then transformed to the gray window by pallette fitting method and the contrast of the reprocessed portal images were evaluated for image improvement. Portal images of patients were also taken at various anatomic sites and the images were processed by Gray Scale Expansion (GSE) method. The patient images were analyzed to examine the feasibility of using the GSE technique in clinic. Results : The histogram distribution showed that minimum and maximum gray scale ranges of 3192 and 21940 were obtained when the image was scanned using logarithmic method and square root method, respectively. Out of 256 gray scale, ony 7 to 30% of the steps were used. After expanding the gray scale to full range, contrast of the portal images were improved . Experiment performed with patient image showed that improved identification of organs were achieved by GSE in portal images of knee joint, head and neck, lung, and pelvis. Conclusion : Phantom study demonstrated that the GSE technique improved image contrast of a linacgram. This indicates that the decrease in image quality resulting from the dual exposure, could be improved by expanding the gray scale. As a result, the improved technique will make it possible to compare the digitally reconstructed radiographs (DRR) and simulation image for evaluation the patient positioning error.
EWHA Breast Device(EBD)의 제작 및 유용성 평가
변영식,오태성,박종일,신현교,Byun Young-Sik,Oh Tae-Sung,Park Chong-Yil,Shin Hyun-Kyoh 대한방사선치료학회 2005 대한방사선치료학회지 Vol.17 No.1
Purpose : We recently perform the latest radiotheraphy (3D conformal, IMRT,etc.) with the development of 3D CT planning technology. However, in case patients with breast cancer, it is difficult to acquire the CT image with the limitation of CT hole size and tilting of breast immobilization device. The Ewha Breast Device(EBD) was constructed to improve the problem in the treatment of patients with breast cancer and we are intend to introduce the procedure of the EBD construction in this study and compare the EBD with conventional breast device in the view point of usefulness. Materials and Methods : We have constructed the EBD with acryl, analyze the skull size with CT data, consider the skin folder in SCL field and evaluated the EBD usefulness from the view point of set-up reproducibility, dose distribution, skin reaction in comparison with conventional breast device. Results : In the case of patients set-up error analysis, the EBD is superior to conventional device in portal film repetition($\%$) check (80pt.), equal to that in simulation & CT image coincidence check(5pt.). There is no difference between the two systems in dose distribution and skin reaction in SCL field is better the EBD than conventional device. Conclusions : The construction of the EBD enable us to perform the latest radiotheraphy in breast treatments, relieve the pains in simulation, and reduce, the skin reaction. In the future, we expect that modification of the EBD is useful in treating for patients with breast cancer.