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A new method and device of aligning patient setup lasers in radiation therapy
Hwang, Ui‐,Jung,Jo, Kwanghyun,Lim, Young Kyung,Kwak, Jung Won,Choi, Sang Hyoun,Jeong, Chiyoung,Kim, Mi Young,Jeong, Jong Hwi,Shin, Dongho,Lee, Se Byeong,Park, Jeong‐,Hoon,Park, Sung Yong,K unknown 2016 Journal of applied clinical medical physics Vol.17 No.1
<P>The aim of this study is to develop a new method to align the patient setup lasers in a radiation therapy treatment room and examine its validity and efficiency. The new laser alignment method is realized by a device composed of both a metallic base plate and a few acrylic transparent plates. Except one, every plate has either a crosshair line (CHL) or a single vertical line that is used for alignment. Two holders for radiochromic film insertion are prepared in the device to find a radiation isocenter. The right laser positions can be found optically by matching the shadows of all the CHLs in the gantry head and the device. The reproducibility, accuracy, and efficiency of laser alignment and the dependency on the position error of the light source were evaluated by comparing the means and the standard deviations of the measured laser positions. After the optical alignment of the lasers, the radiation isocenter was found by the gantry and collimator star shots, and then the lasers were translated parallel to the isocenter. In the laser position reproducibility test, the mean and standard deviation on the wall of treatment room were 32.3±0.93 mm for the new method whereas they were 33.4±1.49 mm for the conventional method. The mean alignment accuracy was 1.4 mm for the new method, and 2.1 mm for the conventional method on the walls. In the test of the dependency on the light source position error, the mean laser position was shifted just by a similar amount of the shift of the light source in the new method, but it was greatly magnified in the conventional method. In this study, a new laser alignment method was devised and evaluated successfully. The new method provided more accurate, more reproducible, and faster alignment of the lasers than the conventional method.</P><P>PACS numbers: 87.56.Fc, 87.53.Bn, 87.53.Kn, 87.53.Ly, 87.55.Gh</P>
김상일(Sang-Il Kim),임병옥(Byeong-Ok Lim),최길웅(Gil-Wong Choi),이복형(Bok-Hyung Lee),김형주(Hyoung-Joo Kim),김륜휘(Ryun-Hwi Kim),임기식(Ki-Sik Im),이정희(Jung-Hee Lee),이정수(Jung-Soo Lee),이종민(Jong-Min Lee) 한국전자파학회 2013 한국전자파학회논문지 Vol.24 No.2
본 논문에서는 Si가 도핑된 Modulation-doped AlGaN/GaN 이종 접합 구조를 가지는 전력증폭기용 MISHFET 소자를 제작하였다. 제작된 GaN TR 소자는 6H-SiC(0001)의 Substrate 위에 성장시켰으며, 180 nm의 gate length를 가진다. 제작된 소자를 측정한 결과, 837 ㎃/㎜의 최대 드레인 전류 특성, 177 mS/㎜의 gm(Tranconductance)을 가지며, fT는 45.6 ㎓, f㎃X는 46.5 ㎓로 9.3 ㎓에서 1.54 W/㎜의 전력 밀도와 40.24 %의 PAE를 가지는 것으로 확인되었다. This letter presents the MISHFET with si-doped AlGaN/GaN heterostructure for power amplifier. The device grown on 6H-SiC(0001) substrate with a gate length of 180 nm has been fabricated. The fabricated device exhibited ㎃ximum drain current density of 837 ㎃/㎜ and peak transconductance of 177 mS/㎜. A unity current gain cutoff frequency was 45.6 ㎓ and maximum frequency of oscillation was 46.5 ㎓. The reported output power density was 1.54 W/㎜ and A PAE(Power Added Efficiency) was 40.24 % at 9.3 ㎓.
Kang, Dong-Hyeon,Eum, Min-Sik,Lee, Byeong-No,Bae, Tae-Sung,Lee, Kyu-Reon,Lim, Heung-Bin,Hur, Nam-Hwi Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.10
Confined Pt and $CoFe_2O_4$ nanoparticles (NPs) in a mesoporous core/shell silica microsphere, Pt-$CoFe_2O_4$@meso-$SiO_2$, were prepared using a bi-functional linker molecule. A large number of Pt NPs in Pt-$CoFe_2O_4$@meso-$SiO_2$, ranging from 5 to 8 nm, are embedded into the shell and some of them are in close contact with $CoFe_2O_4$ NPs. The hydrogenation of cyclohexene over the Pt-$CoFe_2O_4$@meso-$SiO_2$ microsphere at $25^{\circ}C$ and 1 atm of $H_2$ yields cyclohexane as a major product. In addition, it gives oxygenated products. Control experiments with $^{18}O$-labelled water and acetone suggest that surface-bound oxygen atoms in $CoFe_2O_4$ are associated with the formation of the oxygenated products. This oxidation reaction is operative only if $CoFe_2O_4$ and Pt NPs are in close contact. The Pt-$CoFe_2O_4$@meso-$SiO_2$ catalyst is separated simply by a magnet, which can be re-used without affecting the catalytic efficiency.
황태욱 ( Tae-uk Hwang ),임수진 ( Su-jin Lim ),이재휘 ( Jae-hwi Lee ),허병규 ( Byeong-gyu Heo ),박상은 ( Sang-eun Park ),김정민 ( Jeong-min Kim ) 한국정보처리학회 2022 한국정보처리학회 학술대회논문집 Vol.29 No.2
울산항에서 일어나는 선박사고를 줄이고자 실제 산업환경정보를 수집하여 관제서버로 전송할 수 있는 기능을 갖춘 수상드론과 소형선박 운항자들을 대상으로 제작된 메타환경에서의 모의 운항을 할 수 있는 시뮬레이터를 제작하여 안전한 산업환경을 만들기 위해 복합적인 항만 안전운항관리 솔루션을 구축하고자 한다.
Feasibility Test of Flat-Type Faraday Cup for Ultrahigh-Dose-Rate Transmission Proton Beam Therapy
Sang-il Pak,Sungkoo Cho,Seohyeon An,Seonghoon Jeong,Dongho Shin,Youngkyung Lim,Jong Hwi Jeong,Haksoo Kim,Se Byeong Lee Korean Society of Medical Physics 2022 의학물리 Vol.33 No.4
Purpose: Proton therapy has been used for optimal cancer treatment by adapting its Bragg-peak characteristics. Recently, a tissue-sparing effect was introduced in ultrahigh-dose-rate (FLASH) radiation; the high-energy transmission proton beam is considered in proton FLASH therapy. In measuring high-energy/ultrahigh-dose-rate proton beam, Faraday Cup is considered as a dose-rate-independent measurement device, which has been widely studied. In this paper, the feasibility of the simply designed Faraday Cup (Poor Man's Faraday Cup, PMFC) for transmission proton FLASH therapy is investigated. Methods: In general, Faraday cups were used in the measurement of charged particles. The simply designed Faraday Cup and Advanced Markus ion chamber were used for high-energy proton beam measurement in this study. Results: The PMFC shows an acceptable performance, including accuracy in general dosimetric tests. The PMFC has a linear response to the dose and dose rate. The proton fluence was decreased with the increase of depth until the depth was near the proton beam range. Regarding secondary particles backscatter from PMFC, the effect was negligible. Conclusions: In this study, we performed an experiment to investigate the feasibility of PMFC for measuring high-energy proton beams. The PMFC can be used as a beam stopper and secondary monitoring system for transmission proton beam FLASH therapy.
Dosimetric Impact of Ti Mesh on Proton Beam Therapy
Cho, Shinhaeng,Goh, Youngmoon,Kim, Chankyu,Kim, Haksoo,Jeong, Jong Hwi,Lim, Young Kyung,Lee, Se Byeong,Shin, Dongho Korean Society of Medical Physics 2017 의학물리 Vol.28 No.4
When a high density metallic implant is placed in the path of the proton beam, spatial heterogeneity can be caused due to artifacts in three dimensional (3D) computed tomography (CT) scans. These artifacts result in range uncertainty in dose calculation in treatment planning system (TPS). And this uncertainty may cause significant underdosing to the target volume or overdosing to normal tissue beyond the target. In clinical cases, metal implants must be placed in the beam path in order to preserve organ at risk (OARs) and increase target coverage for tumors. So we should introduce Ti-mesh. In this paper, we measured the lateral dose profile for proton beam using an EBT3 film to confirm dosimetric impact of Ti-mesh when the Ti-mesh plate was placed in the proton beam pathway. The effect of Ti-mesh on the proton beam was investigated by comparing the lateral dose profile calculated from TPS with the film-measured value under the same conditions.
Toward a novel dosimetry system using acrylic disk radiation sensor for proton pencil beam scanning
Cho, Shinhaeng,Lee, Nuri,Song, Sanghyeon,Son, Jaeman,Kim, Haksoo,Jeong, Jong Hwi,Lee, Se Byeong,Lim, Youngkyung,Moon, Sunyoung,Yoon, Myonggeun,Shin, Dongho Published for the American Association of Physicis 2018 Medical physics Vol.45 No.11