Seung-wook Shin

A parallel algorithm for large-scale linear programs with a special structure

A new sequential algorithm and computational results for large-scale linear programs with a special structure were presented previously by J.B. Rosen and S. Oh (1992). A parallel version of the algorithm is developed for a hypercube multiprocessor architecture NCUBE2. Computational results using 128 processors are presented for a randomly generated large-scale sparse or dense problems with the number of variables up to 256 and constraints up to 5 million.<<ETX>>

Design of Control System for Dual-Head Radiation Therapy

Sungkyunkwan University groups have been developed advanced radiation therapy machine named dual-head radiation therapy gantry for reducing the treatment time by up to 30%. The main difference between previous radiation therapy machine [1] is using two electron LINAC as X-ray sources at radiation therapy. In support of this system, control system based on SCADA and hardware development was implemented. The control system consists of supervisory computers and local controllers and the control network was ethernet and software was written by labVIEW. An overview of this control system is presented in paper. INTRODUCTION Sungkyunkwan University has developed a dual head radiation therapy system since 2012, which is a radiation therapy system that aims to reduce treatment time up to 30% than conventional radiation therapy machine [2]. To reduce treatment time, dual X-ray source, head are equipped with this system. developed dual-head gantry system is shown in Fig. 1. Those system configurations have economic benefits and advantages on account of reducing radiation treatment time but the additional installation of components result in space limit and a complexity of the system. To overcome space limit, we use 6 MeV Xband LINAC as X-ray source and it sufficiently reduce not only cavity volume but also waveguide and magnetron [3]. Controlling dual X-ray source is new challenge. in contrast to conventional TomoTherapy that use single X-ray source, dual head gantry system uses dual X-ray sources ssimultaneously or sequentially so control system requires supervisory control and sequence control that not only include data acquisition and monitoring but also two electron LINAC beam pulse synchronization. Figure 1: Dual-head Radiation therapy system. SYSTEM HARDWARE CONFIGURATION Developed gantry system is consist of subsystems such as two heads, electron LINAC and gantry robot and subsystems have each local controller. Head subsystem objective is to control the radiation path from the LINAC to the patient. It measures radiation dose rate and control X-ray field size. Its appearance is shown in Fig. 2 Head’s main control unit is Atmega2560 and control board has potential meters and limit switches for interlock. Figure 2: Gantry Head Appearance. Five motors in head system have each driver. By using daisy-chain scheme, master motor manages other slave motors as shown in Fig. 3. Figure 3: Gantry head system block diagram. 9th International Particle Accelerator Conference IPAC2018, Vancouver, BC, Canada JACoW Publishing ISBN: 978-3-95450-184-7 doi:10.18429/JACoW-IPAC2018-THPML076

Development of new 116Cd/Pt target for cyclotron produced 117mSn as a medical radiometal

The radioisotope 117mSn has recently attracted considerable attention because of its application in theranostics and its imaging using 159-keV γ-photons. In this study, we developed a target system that yielded 117mSn via a 116Cd(α, 3n)117mSn nuclear reaction. A separable Pt substrate was utilized to prepare the enriched 116Cd target to be irradiated, and the enriched 116Cd in a cadmium acetate solution was electroplated onto the Pt substrate. The substrate was thermally analyzed via ANSYS simulations, and the plating thickness was optimized through calculations with TALYS code. The production of 117mSn was confirmed through the emission measurement of inherent gamma rays.