Measurement and Simulation of the Counting Efficiency of a Whole-body Counter Using a BOMAB Phantom Inserted with Rod Sources Containing Mixed Radionuclides :

Park, MinSeok,Yoo, Jaeryong,Ha, Wi-Ho,Park, Sunhoo,Jin, Young Woo Pergamon Press 2018 Health physics Vol.114 No.3

<P>The examination of internal contamination is important for providing an adequate medical response during a radiological emergency. A whole-body counting system can assess gamma-emitting radionuclides in a human body when monitoring internal contamination. It is necessary to calibrate whole-body counting systems by using a calibration phantom, such as a Bottle Manikin Absorption phantom, to properly assess internal contamination. However, the total weight of the Bottle Manikin Absorber phantom is high, and there can be leakage of radioactive sources, which are disadvantages of using such a phantom. This study proposes a calibration phantom that is designed to overcome these disadvantages. The proposed phantom consists of rod sources that are inserted in each part of the phantom. The counting efficiency of the rod-source-inserted calibration phantom was acquired using a Monte Carlo simulation method, but the results were evaluated by comparing the experimental efficiencies with those of a conventional Bottle Manikin Absorption phantom by using two commercial whole-body counting systems (stand-up type and bed type). The efficiency curve of the rod-source-inserted phantom matched well that of the conventional calibration phantom. The relative deviation between the efficiencies of the conventional Bottle Manikin Absorption phantom and the proposed calibration phantom in both whole-body counting systems was less than 11%, and the total weight of the phantom was also reduced. These results suggest that the proposed phantom can be manipulated more easily and replace the conventional Bottle Manikin Absorption calibration phantom for these two types of whole-body counting systems.</P>

Establishment of animal model for the analysis of cancer cell metastasis during radiotherapy

Park, Jong Kuk,Jang, Su Jin,Kang, Sung Wook,Park, Sunhoo,Hwang, Sang-Gu,Kim, Wun-Jae,Kang, Joo Hyun,Um, Hong-Duck BioMed Central 2012 Radiation oncology Vol.7 No.-

<P><B>Background</B></P><P>Γ-Ionizing radiation (IR) therapy is one of major therapeutic tools in cancer treatment. Nevertheless, γ-IR therapy failed due to occurrence of metastasis, which constitutes a significant obstacle in cancer treatment. The main aim of this investigation was to construct animal model which present metastasis during radiotherapy in a mouse system <I>in vivo</I> and establishes the molecular mechanisms involved.</P><P><B>Materials and methods</B></P><P>The C6L transfectant cell line expressing firefly luciferase (fLuc) was treated with γ-IR, followed by immunoblotting, zymography and invasion assay <I>in vitro.</I> We additionally employed the C6L transfectant cell line to construct xenografts in nude mice, which were irradiated with γ-IR. Irradiated xenograft-containing mice were analyzed via survival curves, measurement of tumor size, and bioluminescence imaging <I>in vivo</I> and <I>ex vivo</I>. Metastatic lesions in organs of mice were further assessed using RT-PCR, H & E staining and immunohistochemistry.</P><P><B>Results</B></P><P>γ-IR treatment of C6L cells induced epithelial-mesenchymal transition (EMT) and increased cell invasion. In irradiated xenograft-containing mice, tumor sizes were decreased dramatically and survival rates extended. Almost all non-irradiated xenograft-containing control mice had died within 4 weeks. However, we also observed luminescence signals in about 22.5% of γ-IR-treated mice. Intestines or lungs of mice displaying luminescence signals contained several lesions, which expressed the fLuc gene and presented histological features of cancer tissues as well as expression of EMT markers.</P><P><B>Conclusions</B></P><P>These findings collectively indicate that occurrences of metastases during γ-IR treatment accompanied induction of EMT markers, including increased MMP activity. Establishment of a murine metastasis model during γ-IR treatment should aid in drug development against cancer metastasis and increase our understanding of the mechanisms underlying the metastatic process.</P>

Development of a minipig physical phantom from CT data

Park, Sooyeun,Lee, Pilsoo,Ha, Wi-Ho,Kim, Han Sung,Park, Byeong Ryong,Kim, Jae ,Seok,Shim, Sehwan,Park, Sunhoo,Kim, Young-su,Kim, Chan Hyeong,Jin, Young-Woo JAPAN RADIATION RESEACH SOCIETY 2017 JOURNAL OF RADIATION RESEARCH Vol.58 No.5

<P><B>ABSTRACT</B></P><P>Quantification of pathological progression of radiation-induced injury is essential in development of treatment methods, and a proper animal model is necessary for relevant radiological and medical studies. A minipig is a current animal model selected because of its similarities to humans in anatomy and pathology. In the present study, a minipig physical phantom was developed using computed tomography (CT) data. For dosimetry purposes, the minipig physical phantom was constructed on a slice-by-slice basis, with an array of holes to accommodate dosimeters. The phantom is constituted of three major organs, i.e. bone, lung, and remaining soft tissue, and the organs are clearly distinguishable on each 20-mm-thick axial slice. The quality of the tissue-equivalent (TE) substitutes was analyzed in terms of the atomic compositions and Hounsfield units (HUs). The density (in g/cm<SUP>3</SUP>) and effective atomic number of TE substitutes for the bone, lung, and soft tissue are 1.4 and 7.9, 0.5 and 10.0, and 1.0 and 5.9, respectively. Although the TE substitutes have slightly different physical properties, we think the phantom is acceptable because the HU values of the TE substitutes lie in the HU range of real tissues.</P>

Risk Stratification for Serosal Invasion Using Preoperative Predictors in Patients with Advanced Gastric Cancer

Park, Sung-Sil,Min, Jae-Seok,Lee, Kyu-Jae,Jin, Sung-Ho,Park, Sunhoo,Bang, Ho-Yoon,Yu, Hwang-Jong,Lee, Jong-Inn The Korean Gastric Cancer Association 2012 Journal of gastric cancer Vol.12 No.3

Purpose: Although serosal invasion is a critical predisposing factor for peritoneal dissemination in advanced gastric cancer, the accuracy of preoperative assessment using routine imaging studies is unsatisfactory. This study was conducted to identify high-risk group for serosal invasion using preoperative factors in patients with advanced gastric cancer. Materials and Methods: We retrospectively analyzed clinicopathological features of 3,529 advanced gastric cancer patients with Borrmann type I/II/III who underwent gastrectomy at Korea Cancer Center Hospital between 1991 and 2005. We stratified patients into low-(${\leq}40%$), intermediate-(40~70%), and high-risk (>70%) groups, according to the probability of serosal invasion. Results: Borrmann type, size, longitudinal and circumferential location, and histology of tumors were independent risk factors for serosal invasion. Most tumors of whole stomach location or encircling type had serosal invasion, so they belonged to high-risk group. Patients were subdivided into 12 subgroups in combination of Borrmann type, size, and histology. A subgroup with Borrmann type II, large size (${\geq}7$ cm), and undifferentiated histology and 2 subgroups with Borrmann type III, large size, and regardless of histology belonged to high-risk group and corresponded to 25% of eligible patients. Conclusions: This study have documented high-risk group for serosal invasion using preoperative predictors. And risk stratification for serosal invasion through the combination with imaging studies may collaboratively improve the accuracy of preoperative assessment, reduce the number of eligible patients for further staging laparoscopy, and optimize therapeutic strategy for each individual patient prior to surgery.

Positive selection of type II collagen-reactive CD80^high marginal zone B cells in DBA/1 mice

Park, Chanho,Kho, In Seong,In Yang, Jeong,Kim, Min-Jung,Park, Sunhoo,Cha, Hoon-Suk,Lee, Jaejoon,Kim, Tae Jin Elsevier 2017 Clinical immunology Vol.178 No.-

<P><B>Abstract</B></P> <P>To investigate whether dysregulated selection of autoreactive marginal zone (MZ) B cells is involved in autoimmune diseases, we examined MZ B cell profile in multiple strains of mice, and found that type II collagen (CII)-reactive autoreactive CD80<SUP>high</SUP> MZ B cells spontaneously developed in the DBA/1, but not in C57BL/6 mice. CD80<SUP>high</SUP> MZ B cells that were characteristically found in DBA/1 mice expressed higher levels of TACI, SLAM3, and SLAM6 than the usual CD80<SUP>low</SUP> MZ B cells. Notably, the CD80<SUP>high</SUP> MZ B cells were more sensitive to ibrutinib, a Bruton's tyrosine kinase inhibitor, than CD80<SUP>low</SUP> MZ or follicular B cells and their transient depletion via intravenous injection of ibrutinib significantly delayed the induction of collagen-induced arthritis (CIA). In summary, we suggest that the positive selection of CII-reactive CD80<SUP>high</SUP> MZ B cells is a critical homeostatic process predisposing the DBA/1 mice to the CIA induction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> DBA/1 mice show pronounced expansion of marginal zone B cells consisting of distinct CD80<SUP>high</SUP> and CD80<SUP>low</SUP> populations. </LI> <LI> Autoreactive anti-type II collagen CD80<SUP>high</SUP> marginal zone B cells are positively selected in DBA/1 mice. </LI> <LI> Treatment with a BTK inhibitor ibrutinib selectively reduces the survival of CD80<SUP>high</SUP> marginal zone B cells in DBA/1 mice. </LI> <LI> Depletion of CD80<SUP>high</SUP> marginal zone B cells significantly delayed the onset of collagen-induced arthritis in DBA/1 mice. </LI> </UL> </P>

동적 유입류 기법에 의거한 다중 로터 무인비행체의 공기역학 간섭 예측

박선후(SunHoo Park),임병욱(ByeongUk Im),이동열(DongYeol Lee),신상준(SangJoon Shin) 한국항공우주학회 2023 한국항공우주학회 학술발표회 논문집 Vol.2023 No.4

Co-rotational Plane Beam-Dynamic Tip Load를 이용한 Drone Single Arm의 최적 설계

박선후(SunHoo Park),이상구(SangGu Lee),신상준(SangJoon Shin) 한국항공우주학회 2017 韓國航空宇宙學會誌 Vol.45 No.10

본 논문에서는 단일 보의 최적 설계를 활용하여 드론 플랫폼을 구축하였다. 단일 보를끝 단 질량을 가진 외팔보로 가정하였다. 수치 최적화 이론에 기초하여, ANSYS가 얻은 유사한 결과와 비교함으로써 새로운 설계의 검증 및 최적화를 수행 하였다. 마지막으로, 이 설계는 제어 시뮬레이션에 반영되며 공진 상황을 고려한 최적의 구조 설계 요구 사항을 만족함을 보였다. This paper aims to build a drone platform based on an optimum design of its single arm. Its single arm is assumed as a cantilevered beam with a tip mass. Based on the numerical optimization theory, validation and optimization of a new design is conducted by comparing the results with the similar ones obtained by ANSYS. Finally, this design is reflected in the control simulation, and the requirement of an optimum structural design considering the resonance situation is satisfied.

무인비행체 비행 안전도 평가 및 정밀 시뮬레이션

박선후(SunHoo Park),이시훈(SiHun Lee),유정욱(JeongUk Yoo),신상준(SangJoon Shin) 한국항공우주학회 2020 한국항공우주학회 학술발표회 논문집 Vol.2020 No.7

비행 조건의 영향을 고려한 쿼드콥터형 무인비행체의 로터 공력 특성 예측

박선후(SunHoo Park),은원종(WonJong Eun),신상준(SangJoon Shin) 한국항공우주학회 2018 韓國航空宇宙學會誌 Vol.46 No.10

본 연구에서는 무임 회전익기의 종류인 쿼드콥터의 로터 블레이드에 대해 바람 및 비행 조건의 따른 공력특성을 예측하고자 한다. 돌풍 및 비행 조건들을 고려하기 위해 바람의 좌표계 변환 개념을 제시하였다. 강체 블레이드 플래핑 운동방정식을 고려한 깃 요소 및 운동량 이론을 이용해 개별 로터의 제자리, 전지, 상승 비행을 해석하였다. XFOIL을 사용하여 공력결과를 도출하였고, 개발된 BEMT를 이용하여 제자리 비행, 전진, 상승 조건의 검증을 수행했다. 또한 제자리 비행 실험 환경 구축 및 실험 결과와 개발된 BEMT의 비교 및 검증을 수행하였다. This paper aims to predict the aerodynamic characteristics of individual rotor for the gust and flight conditions. Transformation procedure into the wind frame is conducted to analyze the gust. Hover, forward, and climb flight conditions of an individual rotor are analyzed using the blade element momentum theory (BEMT) considering the rigid blade flapping motion. XFOIL is used to derive aerodynamic results. Validation for hover, forward flight, and climb conditions are conducted using the present BEMT. In addition, a static experimental environment is constructed. The experimental results and the present BEMT are compared and verified.

동적 유입류에 의거한 무인비행체 로터의 공기역학 정밀 예측

박선후(SunHoo Park),이시훈(SiHun Lee),유정욱(JeongUk Yoo),신상준(SangJoon Shin) 한국항공우주학회 2020 한국항공우주학회 학술발표회 논문집 Vol.2020 No.11