유방암 방사선치료 시 최적의 방사선치료계획기법에 대한 고찰

김영범,이상록,정세영,권영호,Kim, Young-Bum,Lee, Sang-Rok,Chung, Se-Young,Kwon, Young-Ho 대한방사선치료학회 2006 대한방사선치료학회지 Vol.18 No.1

Purpose: A various find of radiotherapy treatment plans have been made to determine appropriate doses for breasts, chest walls and loco-regional lymphatics in the radiotherapy of breast cancers. The aim of this study was to evaluate the optimum radiotherapy plan technique method by analyzing dose distributions qualitatively and quantitatively. Materials and Methods: To evaluate the optimum breast cancer radiotherapy plan technique, the traditional method(two dimensional method) and computed tomography image are adopted to get breast volume, and they are compared with the three-dimensional conformal radiography (3DCRT) and the intensity modulated radiotherapy (IMRT). For this, the regions of interest (ROI) such as breasts, chest walls, loco-regional lymphatics and lungs were marked on the humanoid phantom, and the computed tomography(Volume, Siemens, USA) was conducted. Using the computed tomography image obtained, radiotherapy treatment plans (XiO 5.2.1, FOCUS, USA) were made and compared with the traditional methods by applying 3DCRT and IMRT. The comparison and analysis were made by analyzing and conducting radiation dose distribution and dose-volume histogram (DVH) based upon radiotherapy techniques (2D, 3DCRT, IMRT) and point doses for the regions of interest. Again, treatment efficiency was evaluated based upon time-labor. Results: It was found that the case of using 3DCRT plan techniques by getting breast volume is more useful than the traditional methods in terms of tumor delineation, beam direction and confirmation of field boundary. Conclusion: It was possible to present the optimum radiotherapy plan techniques through qualitative and quantitative analyses based upon radiotherapy plan techniques in case of breast cancer radiotherapy. However, further studies are required for the problems with patient setup reproducibility arising from the difficulties of planning target volume (PVT) and breast immobilization in case of three-dimensional radiotherapy planning.

해상 환경에서의 무선 이동 통신을 위한 선박용 Ad-hoc 네트워크 운용 시나리오

김영범,장경희,윤창호,박종원,임용곤,Kim, Young-Bum,Chang, Kyung-Hi,Yun, Chang-Ho,Park, Jong-Won,Lim, Yong-Kon 한국정보통신학회 2009 한국정보통신학회논문지 Vol.13 No.10

육상에서는 기지국을 통해 고속의 무선 통신 시스템을 사용하고 없는 반면, 해상의 경우 기지국을 설치하는데 제약이 따르고, 이로 인해 긴 전송거리를 갖는 저속의 MF/HF 대역 모뎀을 주로 사용 하고 있다. 고속 전송을 위해 해상위성통신이 사용되기도 하지만, 비용이 비싸다는 단점을 가지고 있다. 낮은 비용으로 전송속도를 증가시키기 위해서는 Vehicular Ad-hoc Network (VANET)과 같은 기지국이 없는 상황에서 단말간의 통신이 가능한 네트워크의 구성이 필요한데, 해상의 경우 육상과는 다른 환경적인 특징들을 갖기 때문에 본 논문에서는 해상에서의 Ad-hoc 네트워크를 Nautical Ad-hoc Network (NANET) 이라 칭하며 NANET을 위한 시나리오를 설정하고, 시나리오 별 Multiple Access 및 Duplex 방식을 분석한 후, NANET을 구축하기 위한 주요 후속 연구 주제들을 정리하여 해상 무선 통신 연구를 위한 기본적인 Guide Line을 제시한다. In terrestrial communications, high data rate transmission can be achieved by splitting the coverage area into small cells through base stations and reusing the resource efficiently. However, the geographical features of maritime communications require the long transmission range, and it is not practical to install base station on the sea to set up the similar deployment as the terrestrial communications, so MF/HF band modem with low data rate are currently utilized for maritime communications. And the expensive satellite communication via Inmarsat is the conventional solution for the high data rate transmission on the sea. To reduce the cost, Ad-hoc network is proposed to apply on the sea, which requires no base station for the peer-to-peer communications. In this paper, we denominate this maritime environment specific Ad-hoc network as Nautical Ad-hoc Network (NANET). Furthermore, the deployment scenario for the NANET, and the analysis on multiple access and duplexing schemes for the NANET are discussed in this paper, which serves as the cornerstone for the further NANET research and development.

정보시대 새로운 출판운동의 모색

김영범,Kim, Yeong-Beom 대한출판문화협회 1997 출판저널 Vol.218 No.-

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.

Mesh Networks을 위한 다중채널 다중인터페이스 MAC 프로토콜에 관한 연구

김영범,Kim, Young-Beom 한국정보통신학회 2011 한국정보통신학회논문지 Vol.15 No.7

본 논문에서는 무선 애드혹 네트워크에서 복수개 채널을 이용한 효율적인 매체접속제어 프로토콜로써 DM-MMAC (Doze Mode Multi-Chanel MAC)을 제안한다. 기존의 IEEE 802.11 프로토콜의 경우 물리계층에서 복수개의 가용 채널이 주어지나 MAC 계층에서는 오직 고정된 단일채널을 통한 접속만이 가능하다. 이를 보완하기 위한 프로토콜로써 여러 가지 멀티채널 MAC 프로토콜이 제안되었으나 대부분의 경우 채널수가 적고 호스트의 수가 많아지면 전송 처리율(throughput)이 급격히 저하되는 문제점이 있다. 본 연구에서는 기존 MMAC 프로토콜의 채널 할당 및 채널점유 과정을 단순화하고 호스트 간 충돌가능성을 줄임으로써 절전효과와 함께 전송률 향상을 도모하였다. In this paper, we propose a new MAC protocol, namely DM-MMAC (Doze Mode Multi-Channel MAC) for ad hoe wireless networks which can utilize multiple channels effectively, thereby enhancing the network throughput considerably. Basically, the IEEE 802.11 specification allows for the use of multiple channels available at the physical layer, but its MAC protocol is designed only for a single channel with the fatal drawback, so called multi-channel hidden terminal problem in multi-channel environments. In this vein, several multi-channel MAC protocols have been proposed, but most of them demonstrate the performance problem that its throughput drastically decreases as the number of mobile hosts residing in a given network increases with small number of available channels. In this work, we tried to improve the performance of multi-channel MAC protocols in terms of network throughput as well as power saving effects by simplifying the channel assignment and channel capturing procedures and reducing the possibility of collisions between mobile hosts.

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.

평화정착과 인권의식 개화를 위한 전제조건

김영범,Kim, Yeong-Beom 대한출판문화협회 2000 출판저널 Vol.282 No.-

항등비트율 서비스를 위한 GCRA 폴리싱 알고리즘의 성능 해석

김영범,Kim, Young-Beom 한국정보통신학회 2006 한국정보통신학회논문지 Vol.10 No.12

항등 비트율 서비스를 위한 대표적인 이용자 트래픽 통제 알고리즘인 GCRA에 있어서 네트워크의 과부하와 전송 도중 불가피하게 발생하는 전송지연 변동에 따른 이용자 트래픽의 과도한 손실을 방지하기 위해서는 적절한 전송 지연변동 허용치의 설정이 매우 중요하다. 본 논문에서는 항등 비트율의 소스 트래픽에 대한 GCRA 순응검사에서 지연변동 허용치의 범 위에 따른 GCRA의 성능을 여러 측면에서 분석하고 적절한 지연변동 허용치 설정을 위한 가이드라인을 제시한다. In implementing GCRA, well known as the representative user traffic policing algorithm for constant-bit rate service, it is essential to set proper values for delay variation tolerance in order to prevent network overload and excessive user data loss due to delay variation incurred inevitably during transmission process. In this paper, we investigate the performance of GCRA algorithm for various values of delay variation tolerance and suggest a guideline for setting proper delay variation tolerance values.

병아리의 에너지대사에 미치는 비단백태질소의 영향

김영범,남기택,고태송 ( Y . B . Kim,K . T . Nam,T . S . Koh ) 한국축산학회 1985 한국축산학회지 Vol.27 No.10

In order to investigate an effect of non-protein nitrogen (NPN) on the energy metabolism of chicks, hatched Single Comb White Leghorn male chicks were fed for the first 8 days on a commercial chick mash, followed by 6 days on protein-free diet and the subsequent 6 days on the protein-free diets and protein diets containing 10.59% of crude protein supplemented with 0, 0.5, 1.0 and 1.5% of urea, respectively. When birds were fed on protein-free diets during 6 days of experimental feeding period, protein and lipid retentions were in negative balance. Protein loss was least in birds fed 1.0% of urea and lipid loss decreased in the order of increasing level of urea in the diets. The rate (MEn/GE) of metabolizable energy (MEn) to the gross energy (GE) tended to decrease in birds fed urea and the rate (ER/MEn) of energy retention (GR) to the MEn were -19.5∼-22.0%. The MEn intake and heat production (FIP) per metabolic body size (㎏^(0.75)) was lowered in the order of the increasing level of urea in diets, and ER her ㎏^(0.75) of birds fed 1.0 and 1.5% of urea was increased. Birds fed protein diets containing urea deposited more protein and less lipids compared to those containing no urea. The MEn/GE of protein diets supplemented with the urea were higher and the ER or ER/MFn were lower than those without supplementation. The MGn intake per ㎏^(0.75) of birds fed protein diet containing 1.5% of urea was increased and the ER was lowered in birds fed diets contained urea, and the HP was increased in the order of the increasing levels of urea in the diets.

4MV X-선을 이용한 조직보상체 두께비 연구 및 응용

김영범,정희영,권영호,김유현,Kim Young-Bum,Jung Hee-Young,Kweon Young-Ho,Kim You-Hyun 대한방사선치료학회 1996 大韓放射線治療技術學會誌 Vol.8 No.1

A radiation beam incident on irregular or sloping surface produces an inhomogeneity of absorbed dose. The use of a tissue compensator can partially correct this dose inhomogeneity. The tissue compensator should be made based on experimentally measured thickness ratio. The thickness ratio depends on beam energy, distance from the tissue compensator to the surface of patient, field size, treatment depth, tissue deficit and other factors. In this study, the thickness ratio was measured for various field size of $5cm{\times}5cm,\;10cm{\times}10cm,\;15cm{\times}15cm,\;20cm{\times}20cm$ for 4MV X-ray beams. The distance to the compensator from the X-ray target was fixed, 49cm, and measurement depth was 3, 5, 7, 9 cm. For each measurement depth, the tissue deficit was changed from 0 to(measurement depth-1)cm by 1cm increment. As a result, thickness ratio was decreased according to field size and tissue deficit was increased. Use of a representative thickness ratio for tissue compensator, there was $10\%$ difference of absorbed dose but use of a experimentally measured thickness ratio for tissue compensator, there was $2\%$ difference of absorbed dose. Therefore, it can be concluded that the tissue compensator made by experimentally measured thickness ratio can produce good distribution with acceptable inhomogeneity and such tissue compensator can be effectively applied to clinical radiotherapy.