http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Lee, Minsik,Cho, Min-Seok,Lee, Hoyeon,Chung, Hyekyun,Cho, Byungchul Korean Society of Medical Physics 2017 의학물리 Vol.28 No.4
The purpose of this study is to install a system that compensated for the respiration motion using an articulated robotic manipulator couch which enables a wide range of motions that a Stewart platform cannot provide and to evaluate the performance of various prediction algorithms including proposed algorithm. For that purpose, we built a miniature couch tracking system comprising an articulated robotic manipulator, 3D optical tracking system, a phantom that mimicked respiratory motion, and control software. We performed simulations and experiments using respiratory data of 12 patients to investigate the feasibility of the system and various prediction algorithms, namely linear extrapolation (LE) and double exponential smoothing (ES2) with averaging methods. We confirmed that prediction algorithms worked well during simulation and experiment, with the ES2-averaging algorithm showing the best results. The simulation study showed 43% average and 49% maximum improvement ratios with the ES2-averaging algorithm, and the experimental study with the $QUASAR^{TM}$ phantom showed 51% average and 56% maximum improvement ratios with this algorithm. Our results suggest that the articulated robotic manipulator couch system with the ES2-averaging prediction algorithm can be widely used in the field of radiation therapy, providing a highly efficient and utilizable technology that can enhance the therapeutic effect and improve safety through a noninvasive approach.
Lee Minsik,Cho Min-Seok,Lee Hoyeon,Jeong Chiyoung,Kwak Jungwon,Jung Jinhong,Kim Su Ssan,Yoon Sang Min,Song Si Yeol,Lee Sang-wook,Kim Jong Hoon,Choi Eun Kyung,Cho Seungryong,Cho Byungchul 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.78 No.1
The purpose of this study is to evaluate the performance of a recurrent neural network (RNN)-based prediction algorithm to compensate for respiratory movement using an articulated robotic couch system. A prototype of a real-time respiratory motion compensation couch was built using an optical 3D motion tracking system and a six-degree-of-freedom-articulated robotic system. To compensate for the system latency from motion detection to re-positioning of the system, RNN and double exponential smoothing (ES2) prediction algorithms were applied. Three aspects of performance were evaluated, simulation and experiments for geometric and dosimetric evaluations, using data from three liver and three lung patients who underwent stereotactic body radiotherapy. Overall, the RNN algorithm showed better geometric and dosimetric results than the other approaches. In simulation tests, RNN showed 82% average improvement ratio, compared with non-predicted results. In the geometric evaluation, RNN only showed average FWHM broadening of 1.5 mm, compared with the static case. In the dosimetric evaluation, RNN showed average gamma passing rates of 97.4 ± 1.0%, 89.0 ± 2.4% under the 3%/3 mm, 2%/2 mm respectively. It may be technically feasible to use the RNN prediction algorithm to compensate for respiratory motion with an articulated robotic couch system. The RNN algorithm could be widely used for motion compensation in patients undergoing radiotherapy.
Fully Elastic Conductive Films from Viscoelastic Composites
Cho, Sunghwan,Song, Jun Hyuk,Kong, Minsik,Shin, Sangbaie,Kim, Young-Tae,Park, Gyeongbae,Park, Chan-Gyung,Shin, Tae Joo,Myoung, Jaemin,Jeong, Unyong American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.50
<P>We investigated, for the first time, the conditions where a thermoplastic conductive composite can exhibit completely reversible stretchability at high elongational strains (epsilon = 1.8). We studied a composite of Au nanosheets and a polystyrene-block-polybutadiene-block-polystyrene block copolymer as an example. The composite had an outstandingly low sheet resistance (0.45 Omega/sq). We found that when a thin thermoplastic composite film is placed on a relatively thicker chemically cross-linked elastomer film, it can follow the reversible elastic behavior of the bottom elastomer. Such elasticity comes from the restoration of the block copolymer microstructure. The strong adhesion of the thermoplastic polymer to the metallic fillers is advantageous in the fabrication of mechanically robust, highly conductive, stretchable electrodes. The chemical stability of the Au composite was used to fabricate high luminescence, stretchable electrochemiluminescence displays with a conventional top-bottom electrode setup and with a horizontal electrode setup.</P>
강동욱,Minsik Cho,이대희,Hyunjun Yoo,김명수,Jun Hyung Bae,Hyoungtaek Kim,Jongyul Kim,김현덕,조규성 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.9
Recently large-size 3-Tr active pixel CMOS image sensors have been being used for medium-size digital X-ray radiography such as dental CT, mammography and NDT for consumer products. We designed and fabricated 50 um x 50 um 3-Tr test pixels having a pixel photodiode with various structures and shapes using TSMC 0.25 um standard CMOS process to compare their optical characteristics. The pixel photodiode output was continuously sampled while a test pixel was continuously illuminated by 550 nm light at a constant intensity. The measurement was repeated 300 times for each test pixel to obtain reliable results on the pixel output mean and variance at each sampling time. The sampling rate was 50 kHz and the reset period was 200 msec. To estimate the conversion gain, the mean-variance method was used. From the measured results, the n-well/p-substrate photodiode showed the best performance at a low illumination condition equivalent to typical X-ray signal range among 3 photodiode structures available in a standard CMOS process. Quantum efficiencies of n+/p-well, n-well/p-substrate, and n+/p-substrate were 18.5 %, 62.1 %, and 51.5 %, respectively. From the comparison of pixels with rounded and rectangular corners, we found that rounded corner structure could reduce the dark current in large-size pixels. A pixel with four rounded corners showed the reduced dark current of about 200 fA compared to a pixel with four rectangular corners in our pixel sample size. Photodiodes with round p-implant openings showed about 5 % higher dark current, but about 34 % higher sensitivities than the conventional photodiodes.
Park Minsik,김주환,Kim Taesam,Kim Suji,Park Wonjin,Ha Kwon-Soo,Cho Sung Hwan,원무호,이정형,권영근,김영명 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-
Low-dose metronomic chemotherapy (LDMC) inhibits tumor angiogenesis and growth by targeting tumor-associated endothelial cells, but the molecular mechanism has not been fully elucidated. Here, we examined the functional role of regulated in development and DNA damage responses 1 (REDD1), an inhibitor of mammalian target of rapamycin complex 1 (mTORC1), in LDMC-mediated endothelial cell dysfunction. Low-dose doxorubicin (DOX) treatment induced REDD1 expression in cultured vascular and lymphatic endothelial cells and subsequently repressed the mRNA expression of mTORC1-dependent translation of vascular endothelial growth factor receptor (Vegfr)-2/3, resulting in the inhibition of VEGF-mediated angiogenesis and lymphangiogenesis. These regulatory effects of DOX-induced REDD1 expression were additionally confirmed by loss- and gain-of-function studies. Furthermore, LDMC with DOX significantly suppressed tumor angiogenesis, lymphangiogenesis, vascular permeability, growth, and metastasis in B16 melanoma-bearing wild-type but not Redd1-deficient mice. Altogether, our findings indicate that REDD1 is a crucial determinant of LDMC-mediated functional dysregulation of tumor vascular and lymphatic endothelial cells by translational repression of Vegfr-2/3 transcripts, supporting the potential therapeutic properties of REDD1 in highly progressive or metastatic tumors.