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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.
Kyusun Cho,Jaehoon Ko,Seungryong Kim 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.6
This paper explores the application of 3D-aware GANs in video editing, specifically addressing challenges related to identity preservation and temporal consistency. We propose an optimizationbased inversion pipeline that maps consecutive frames of a portrait video to the latent space of 3Daware GANs. Novel 3D-aware loss functions are employed to reinforce the optimization of latent codes and camera viewpoint, ensuring temporal coherency using estimated optical flow. Additionally, we introduce a strategy to enhance visual quality by addressing focal length inconsistency in each frame. Extensive experiments demonstrate that our method outperforms previous video GAN inversion techniques, maintaining identity and temporal consistency while achieving comparable visual quality and manipulation capabilities. Furthermore, we showcase the versatility of our approach by applying it to tasks such as head pose control and 3D shape generation. This research sheds light on the potential of 3D-aware GANs in video editing, opening new possibilities for future exploration and practical applications.
Feasibility Study of Robotics-based Patient Immobilization Device for Real-time Motion Compensation
Chung, Hyekyun,Cho, Seungryong,Cho, Byungchul Korean Society of Medical Physics 2016 의학물리 Vol.27 No.3
Intrafractional motion of patients, such as respiratory motion during radiation treatment, is an important issue in image-guided radiotherapy. The accuracy of the radiation treatment decreases as the motion range increases. We developed a control system for a robotic patient immobilization system that enables to reduce the range of tumor motion by compensating the tumor motion. Fusion technology, combining robotics and mechatronics, was developed and applied in this study. First, a small-sized prototype was established for use with an industrial miniature robot. The patient immobilization system consisted of an optical tracking system, a robotic couch, a robot controller, and a control program for managing the system components. A multi speed and position control mechanism with three degrees of freedom was designed. The parameters for operating the control system, such as the coordinate transformation parameters and calibration parameters, were measured and evaluated for a prototype device. After developing the control system using the prototype device, a feasibility test on a full-scale patient immobilization system was performed, using a large industrial robot and couch. The performances of both the prototype device and the realistic device were evaluated using a respiratory motion phantom, for several patterns of respiratory motion. For all patterns of motion, the root mean squared error of the corresponding detected motion trajectories were reduced by more than 40%. The proposed system improves the accuracy of the radiation dose delivered to the target and reduces the unwanted irradiation of normal tissue.
Son, Kihong,Cho, Seungryong,Kim, Jin Sung,Han, Youngyih,Ju, Sang Gyu,Choi, Doo Ho unknown 2014 Journal of applied clinical medical physics Vol.15 No.2
<P>Image‐guided techniques for radiation therapy have improved the precision of radiation delivery by sparing normal tissues. Cone‐beam computed tomography (CBCT) has emerged as a key technique for patient positioning and target localization in radiotherapy. Here, we investigated the imaging radiation dose delivered to radiosensitive organs of a patient during CBCT scan. The 4D extended cardiac‐torso (XCAT) phantom and Geant4 Application for Tomographic Emission (GATE) Monte Carlo (MC) simulation tool were used for the study. A computed tomography dose index (CTDI) standard polymethyl methacrylate (PMMA) phantom was used to validate the MC‐based dosimetric evaluation. We implemented an MC model of a clinical on‐board imager integrated with the Trilogy accelerator. The MC model's accuracy was validated by comparing its weighted CTDI (CTDIw) values with those of previous studies, which revealed good agreement. We calculated the absorbed doses of various human organs at different treatment sites such as the head‐and‐neck, chest, abdomen, and pelvis regions, in both standard CBCT scan mode (125 kVp, 80 mA, and 25 ms) and low‐dose scan mode (125 kVp, 40 mA, and 10 ms). In the former mode, the average absorbed doses of the organs in the head and neck and chest regions ranged 4.09‐8.28 cGy, whereas those of the organs in the abdomen and pelvis regions were 4.30‐7.48 cGy. In the latter mode, the absorbed doses of the organs in the head and neck and chest regions ranged 1.61‐1.89 cGy, whereas those of the organs in the abdomen and pelvis region ranged between 0.79‐1.85 cGy. The reduction in the radiation dose in the low‐dose mode compared to the standard mode was about 20%, which is in good agreement with previous reports. We opine that the findings of this study would significantly facilitate decisions regarding the administration of extra imaging doses to radiosensitive organs.</P><P>PACS number: 87.57.uq</P>
Energy-Efficient Probabilistic Routing Algorithm for Internet of Things
Park, Sang-Hyun,Cho, Seungryong,Lee, Jung-Ryun Hindawi Limited 2014 Journal of applied mathematics (JAM) Vol.2014 No.-
<P>In the future network with Internet of Things (IoT), each of the things communicates with the others and acquires information by itself. In distributed networks for IoT, the energy efficiency of the nodes is a key factor in the network performance. In this paper, we propose energy-efficient probabilistic routing (EEPR) algorithm, which controls the transmission of the routing request packets stochastically in order to increase the network lifetime and decrease the packet loss under the flooding algorithm. The proposed EEPR algorithm adopts energy-efficient probabilistic control by simultaneously using the residual energy of each node and ETX metric in the context of the typical AODV protocol. In the simulations, we verify that the proposed algorithm has longer network lifetime and consumes the residual energy of each node more evenly when compared with the typical AODV protocol.</P>
Review of the Existing Relative Biological Effectiveness Models for Carbon Ion Beam Therapy
Kim, Yejin,Kim, Jinsung,Cho, Seungryong Korean Society of Medical Physics 2020 의학물리 Vol.31 No.1
Hadron therapy, such as carbon and helium ions, is increasingly coming to the fore for the treatment of cancers. Such hadron therapy has several advantages over conventional radiotherapy using photons and electrons physically and clinically. These advantages are due to the different physical and biological characteristics of heavy ions including high linear energy transfer and Bragg peak, which lead to the reduced exit dose, lower normal tissue complication probability and the increased relative biological effectiveness (RBE). Despite the promising prospects on the carbon ion radiation therapy, it is in dispute with which bio-mathematical models to calculate the carbon ion RBE. The two most widely used models are local effect model and microdosimetric kinetic model, which are actively utilized in Europe and Japan respectively. Such selection on the RBE model is a crucial issue in that the dose prescription for planning differs according to the models. In this study, we aim to (i) introduce the concept of RBE, (ii) clarify the determinants of RBE, and (iii) compare the existing RBE models for carbon ion therapy.
반도체 본딩 불량 검출을 위한 U-Net 기반 X선 영상 배경 제거
임선호(Sunho Lim),조승룡(Seungryong Cho),이태원(Taewon Lee) 대한전자공학회 2022 대한전자공학회 학술대회 Vol.2022 No.11
Semiconductor packaging technology has been developing in response to the demand for high performance and miniaturization of electronic products. X-rays are inevitably used to detect defects due to bonding methods using wires and bumps used in highly integrated semiconductor chips. However, in the case of an inspection method using a computed tomography (CT) scan, productivity is lowered due to a long imaging time, and more defects are caused due to an increase in the dose to the semiconductor chip. To solve this problem, in this paper, we proposed a preprocessing method that uses U-Net to remove the background information, not the part to be inspected, from the 2D X-ray image of the semiconductor chip, and it was confirmed that the background was successfully removed.