소나무재선충병 피해지에 식재된 편백의 낙엽· 낙지에 의한 탄소 및 질소 유입량

강현철 ( Hyeon Cheol Kang ),백경원 ( Gyeongwon Baek ),최병길 ( Byeonggil Choi ),하지석 ( Jiseok Ha ),김춘식 ( Choonsig Kim ) 한국산림과학회(구 한국임학회) 2021 한국산림과학회지 Vol.110 No.1

소나무재선충병 피해목을 모두베기하거나 미피해 곰솔을 잔존하고 편백을 수하식재 한 15년생 편백 조림지를 대상으로 1년 동안(2018년 12월∼2019년 12월) 낙엽·낙지에 의한 탄소 및 질소 유입량을 조사하였다. 편백의 평균 흉고직경은 모두베기구가 12.10 cm로 수하식재구의 9.42 cm에 비해 유의적으로 크게 나타났다. 편백 낙엽의 유기탄소 및 질소 농도는 모두베기구나 수하식재구 사이에 유의적인 차이(P > 0.05)가 없었으나, 낙엽의 C/N비는 8월∼10월에 유입된 낙엽이 93으로 12월∼3월 사이에 유입된 낙엽의 143보다 유의적으로 낮았다. 낙엽·낙지 구성 성분의 탄소 농도는 곰솔 가지, 편백낙엽, 곰솔 낙엽 등의 탄소 농도가 활엽수나 기타 물질에 비해 유의적으로 높았으며, 질소 농도는 활엽수 잎, 편백 녹엽(green leaf), 기타 물질 등이 편백 낙엽이나 곰솔 가지 등에 비해 높은 농도를 보였다. C/N비는 곰솔 낙엽과 편백 낙엽이 기타 물질, 편백 녹엽, 활엽수 낙엽 등에 비해 유의적으로 높았다. 편백 낙엽에 의한 유기탄소 및 질소 유입량은 모두베기구가 773 kg C ha^-1 yr^-1와 6.95 kg N ha^-1 yr^-1로 수하식재구 78 kg C ha^-1 yr^-1와 0.70 kg N ha^-1 yr^-1에 비해 유의적으로 많은 양이 유입되었다. 그러나 총 유기탄소 및 질소 유입량은 수하식재구 3,765 kg C ha^-1 yr^-1와 47.6 kg N ha^-1 yr^-1, 모두 베기구 1,290 kg C ha^-1 yr^-1와 17.2 kg N ha^-1 yr^-1로 수하식재구가 상층 곰솔의 낙엽·낙지 유입으로 인하여 3배 정도 많았다. 본 연구결과에 따르면 모두베기구에 조성된 편백의 흉고직경 생장은 수하식재구에 비해 양호하였으나, 낙엽·낙지에 의한 탄소 및 질소 유입량은 상당히 감소하는 것으로 나타났다. In this study, carbon (C) and nitrogen (N) inputs by the litterfall of Japanese cypress (Chamaecyparis obtusa Endlicher) planted in pine wilt disease-disturbed forests were determined. The study sites were located in Sacheon-si, Gyeongsangnam-do. Eight plots under two regeneration sites (DR: four plots of C. obtusa planted under slightly disturbed Pinus thunbergii stands; CR: four plots of C. obtusa planted following the clear-cutting of severely disturbed pine stands) were established to collect litterfall from December 2018 to December 2019. The growth of diameter at breast height (DBH) was significantly higher in the CR treatment (12.10 cm) than that in the DR treatment (9.42 cm). C and N concentrations and the C/N ratio in C. obtusa leaf litter did not differ significantly between the two regeneration treatments, but the C/N ratio was significantly lower in the leaf litter collected in October (93) relative to that collected in December (143). The C concentration of litterfall components was significantly higher in C. obtusa leaf litter and in P. thunbergii needle litter than in broadleaved and miscellaneous litter, whereas the N concentration in broadleaved and miscellaneous litter was significantly higher than that in the leaf litter of C. obtusa and in branch litter. Thus, the C/N ratio was significantly higher in C. obtusa leaf litter and branch litter compared with that in miscellaneous and broadleaved litter. Respective C and N inputs by leaf litter were 773 kg C ha^-1 yr^-1 and 6.95 kg N ha ^-1 yr^-1 for the CR treatments, and 78 kg C ha^-1 yr^-1 and 0.70 kg N ha^-1 yr^-1 for the DR treatment. Total C and N inputs were higher for the DR treatment (3,765 kg C ha^-1 yr^-1 and 47.6 kg N ha^-1 yr^-1, respectively) than for the CR treatment (1,290 kg C ha^-1 yr^-1 and 17.2 kg N ha^-1 yr^-1, respectively). These results indicate that, for C. obtusa, the DBH growth in the CR treatment was superior to that in the DR treatment, but the C and N inputs by litterfall were considerably reduced in CR treatments.

부산·울산·경남지역 직업병 감시체계

김정일,김병권,김정원,채창호,이철호,강동묵,김지홍,김진하,김영욱,이영하,이지호,김정호,윤형렬,유철인,정백근,장태원,김운규,윤동영,강진욱,김종은,안진홍,이동준,장준호,이광영,송혜란,최영희,이용환,조병만,최홍렬,고상백,김은아,이유진,홍영습,정갑열,김정만,김준연 大韓産業醫學會 2004 대한직업환경의학회지 Vol.16 No.1

Objective: Occupational medicine specialists in the Busan, Ulsan and Kyung-Nam areas established an area-based occupational disease surveillance system and used this system to collected case information for the purpose of preventing occupational diseases Methods: l l hospital participated in this system. The authors selected five main diseases, which were hand-arm vibration syndrome (HAVS), work-related musculoskeletal disorder (WRMSD), occupational asthma, occupational skin disease and occupational and occupational lung cancer and established their case definitions. All cases were reported on the web, and real time analysis was conducted. Results: Between April 2001 and April 2003, 192 cases of HAVS, 118 cases of WRMSD, 33 cases of occupational asthma, 17 cases of occupational skin disease and 17 cases of occupational lung cancer (for a total of 377 cases of these five main diseases) were reported. most of the HAVS cases came from shipbuilding, and 172 of them (92.7%) were associated with grinding. Of the four main types of WRMSD, carpal tunnel syndrome (CTS) was the most prevalent with 46 cases and shipbuilding was also the main industry involved (83.9%). The ergonomic risk factors involved mainly associated with the hand. In 19 (57.6%) and 4 (12.1%) cases of occupational asthma, the agents involved. The causative agents of occupational lung cancer included Cr, welding fume, PAH, Ni, etc. 10(58.8%) of the cases were diagnosed as squamous cell carcinoma and 5(29.4%) as adenoma. Conclusion: This result showed that an area-based occupational disease surveillance system might provide an effective method of evaluating the prevalence of such diseases, however the Busan, Ulsan and Kyung-Nam provinces are too large to be treated as individual areas. Therefore, the authors suggest that each province should establish its own surveillance system.

Diagnostic X-ray Spectra Detection by Monte Carlo Simulation

Cheol-Ha Baek(백철하),Seung-Jae Lee(이승재),Daehong Kim(김대홍) 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.3

Most diagnostic devices in the medical field use X-ray sources, which emit energy spectra. In radiological diagnosis, the quantitative and qualitative analyses of X-rays are essential for maintaining the image quality and minimizing the radiation dose to patients. This work aims to obtain the X-ray energy spectra used in diagnostic imaging by Monte Carlo simulation. Various X-ray spectra are simulated using a Monte Carlo simulation tool. These spectra are then compared to the reference data obtained with a tungsten anode spectral model using the interpolating polynomial (TASMIP) code. The X-ray tube voltages used are 50, 60, 80, 100, and 110 kV, respectively. CdTe and a-Se detector are used as the detectors for obtaining the X-ray spectra. Simulation results demonstrate that the various X-ray spectra are well matched with the reference data. Based on the simulation results, an appropriate X-ray spectrum, in accordance with the tube voltage, can be selected when generating an image for diagnostic imaging. The dose to be delivered to the patient can be predicted prior to examination in the diagnostic field. 대부분의 진단용 방사선 장치는 엑스선을 사용하며, 엑스선은 다양한 에너지를 갖는 스펙트럼을 갖는다. 진단 영상에서 엑스선의 정량적 및 정성적 분석은 선량을 줄이면서 영상 화질을 유지하는데 필수적이다. 본 연구의 목적은 진단 영상에 사용되는 엑스선 스펙트럼을 몬테칼로 시뮬레이션으로 측정하는 것이다. 다양한 엑스선 에너지 스펙트럼이 몬테칼로 시뮬레이션으로 측정되었다. 이 스펙트럼들은 다항식을 보간 한 양극 텅스텐 모델에 의해 계산된 결과와 비교하였다. 엑스선 관전압은 50, 60, 80, 100, 110 kV 였다. 검출기로는 카드뮴 텔루라이드와 비정질 셀레늄 물질을 사용하였다. 엑스선 에너지 스펙트럼의 시뮬레이션 결과는 참조 결과와 일치하였고, NRMSD 값은 최소 1.1%에서 최대 5.7%를 보였다. 시뮬레이션 결과에 의하면 진단 영상을 획득할 때 적절한 관전압의 선택을 가능하게 할 것이다. 또한, 영상 획득 전 환자에 전달되는 선량을 예측하는데 기여할 것이다.

Radioprotective Effect of HME-Mulberry Leaves against Electromagnetic Radiation-Induced Damage in Rats

Cheol-Ha Baek,Su-Ji Ryu,Hye-Min Kim,Seoul-Hee Nam,Jong-Suep Baek,Byung-In Min,Jang-Oh Kim 한국자기학회 2023 Journal of Magnetics Vol.28 No.4

In this study, a solid dispersion containing mulberry leaves and additives was manufactured by hot-melt extrusion (HME) to develop a radioprotective agent against electromagnetic radiation. The prepared formulations were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and electrophoretic light scattering (ELS). The formation of regular dispersions was confirmed through SEM and TEM analysis. To explore the radioprotective effect, animals were randomly classified into four groups: normal control (NC), irradiation (IR), irradiation after administration with mulberry leaves (MR), and irradiation after administration with HME-mulberry leaves (HR). Each sample was orally administered at 100 ㎎/㎏/day, and 7 Gy of 6 MV electromagnetic radiation (X-ray) was used once for the whole body. Lymphocytes seemed to recover in the HR group, but none of the groups recovered at a normal range by the seventh day after irradiation. There was also no change in all groups of the red blood cells. The spleen index tended to recover in the HR group compared to the IR group, which was consistent with histological analysis. The spleen of the radiation-exposed groups (IR, MR, and HR) showed relatively atrophied white pulp and decreased lymphocytes. These symptoms further increased on the third day after irradiation and gradually alleviated on the seventh day. Compared to the IR group, the MR and HR groups had less loss of lymphocytes caused by damage to the white pulp. Specifically, the HR group demonstrated a higher recovery rate than the MR group, confirming the potential of HME-Mulberry as a radioprotective agent. The study’s findings suggest further studies on health supplements and medicines to supplement the current research.

Simulation Study of a Monochromatic X-ray Beam with K-edge Filter for Low Dose Mammography

Cheol-Ha Baek,Daehong Kim 한국자기학회 2019 Journal of Magnetics Vol.24 No.4

X-ray mammography can be used to acquire images useful for early breast cancer detection in medical applications. There have been a number of approaches to diagnostic low-dose mammography. The purpose of this study was to design a concept for use of monochromatic X-ray beams by using K-edge filters for low dose mammography. The SRS-78 X-ray simulation code and Monte Carlo simulation GATE code were used to model the X-ray tube, target material, filter material, breast phantom, and detector. To achieve a monochromatic X-ray beam, molybdenum (Mo) and rhodium (Rh) were used as filter materials in various thicknesses. The direct conversion detector (FDXD 1417, Drtech, Seongnam, Korea) composed of thin-film transistor (TFT)-amorphous selenium (a-Se) was modelled through Monte Carlo simulation. According to the CVR and EER results, the filter thickness for optimal mammographic imaging is set to 6 and 3 HVL for Mo and Rh, respectively. SNR values with the Rh filter improved by 1.01, 6.28, 5.60, 5.60, 5.60, 5.60 % over the range from 0.1 to 0.6 μGy compared to analogous SNR values without filter. The present work demonstrates that monochromatic X-ray beams can be generated for low dose mammography. According to the results, Rh filter could be useful for enhancing calcification while absorbed dose is reduced.

Monte Carlo Simulation of X-ray beam design for multi-energy imaging with charge-integrating detector Using GATE

Cheol-Ha Baek,Daehong Kim 한국자기학회 2017 한국자기학회 학술연구발표회 논문개요집 Vol.2017 No.5

Optimization of Large-Angle Pinhole Collimator for Environmental Monitoring System

Cheol-Ha Baek,Seung-Jae Lee,Yong Choi,Yong Hyun Chung IEEE 2010 IEEE transactions on nuclear science Vol.57 No.3

<P>The purpose of this study was to optimize a large-angle pinhole collimator using Monte Carlo simulation for nuclear survey imaging. Simulations using GATE (Geant4 Application for Tomographic Emission) were performed to model the pinhole gamma camera system. A gamma camera consists of a cone-shaped pinhole collimator with a tungsten aperture and a CsI(Tl) scintillation crystal 6.0 mm thick and 50.0 mm × 50.0 mm in area. The focal length and the acceptance angle of the pinhole collimator were set to 14.5 mm and 120°, respectively. The intrinsic spatial resolution and sensitivity were simulated by changing the pinhole diameter and channel height. The point source of Tc-99m was located 30.0 mm above the center of the pinhole, and the projection data was estimated for pinhole diameter values from 0.5 mm to 4.0 mm while the channel heights were fixed between knife-edge and 3.0 mm. The optimal ranges of channel height and pinhole diameter were determined through evaluation of the intrinsic resolution and sensitivity tradeoff curves. The simulation results allowed us to determine the optimal values of pinhole diameter and channel height to be 1.5 mm and 0.5 mm, respectively, to get intrinsic resolution below 2.0 mm FWHM with a reasonable sensitivity for the system configured in this study. The resolution and sensitivity were measured experimentally, and the simulated and measured data were in good agreement. The results demonstrated that the pinhole collimator designed in this study could be utilized to create a large-angle radiation monitoring system.</P>

소동물 전용 양전자방출단층시스템의 섬광체 배열에 따른 특성 평가

백철하(Cheol-Ha Baek) 한국콘텐츠학회 2015 한국콘텐츠학회논문지 Vol.15 No.4

본 연구의 목적은 몬테칼로 모사방법을 이용하여 소동물 전용 양전자방출단층촬영 시스템의 모듈 내 섬광체 배열 수에 따른 특성평가를 하는 것이다. 이 연구에서 제안한 소 동물 전용 양전자방출단층촬영 시스템은 모듈 내 섬광체 수를 1 ∼ 8개로 구성하였으며, 섬광체 크기는 2.0 × 2.0 × 10.0 ㎣ 크기의 LSO 섬광결정을 사용하였고 스캐너의 직경은 100 mm로 설계하였다. 몬테칼로 시뮬레이션 방법중에 하나인 GATE 코드를 이용하여 선원은 511 keV 점선원을 이용하였으며 동시계수 측정된 좌표값을 이용하여 민감도 및 사이노그램을 획득하였다. 모듈 내 섬광체 수가 적을수록 모듈 별 틈새가 줄어들어 민감도가 향상되는 결과를 보였으며, 사이노그램 결과에서도 불완전한 데이터(missing data)가 발생하지 않는 것을 알 수 있었다. 이 연구 결과는 모듈 안 섬광체 수가 적을수록 민감도 향상 및 불완전한 데이터 획득이 줄어드는 것을 증명함으로써, 소동물 전용 양전자방출단층촬영 시스템의 성능 개선을 위한 새로운 접근법을 제시한다. The aim of this study is to perform simulations to design the detector module with crystal array by Monte Carlo simulation. For this purpose, a small animal PET scanner, employing module with 1∼8 crystal array discrimination scheme, was designed. The proposed scanner has an inner diameter of 100 mm with detector modules in crystal array. Each module is composed of a 5.0 mm LSO crystal with a 2.0 × 2.0 ㎟ sensitive area with a pitch 2.1 mm and 10.0 mm thickness. The LSO crystals are attached to the SiPM which has a dimension of 2.0 × 2.0 ㎟. The detector module with crystal array of the designed PET detector was simulated using the Monte Carlo code GATE(Geant4 Application for Tomographic Emission). The detector is enough compensation for the loss of data in sinogram due to gaps between modules. The results showed that the high sensitivity and effectively reduced the problem about the missing data were greatly improved by using the detector module with 1 crystal array.

진단용 X-선 스펙트럼의 몬테칼로 전산모사 측정

백철하 ( Cheol-ha Baek ),이승재 ( Seung-jae Lee ),김대홍 ( Daehong Kim ) 한국방사선학회 2018 한국방사선학회 논문지 Vol.12 No.3

대부분의 진단용 방사선 장치는 엑스선을 사용하며, 엑스선은 다양한 에너지를 갖는 스펙트럼을 갖는다. 진단 영상에서 엑스선의 정량적 및 정성적 분석은 선량을 줄이면서 영상 화질을 유지하는데 필수적이다. 본 연구의 목적은 진단 영상에 사용되는 엑스선 스펙트럼을 몬테칼로 시뮬레이션으로 측정하는 것이다. 다양한 엑스선 에너지 스펙트럼이 몬테칼로 시뮬레이션으로 측정되었다. 이 스펙트럼들은 다항식을 보간 한 양극 텅스텐 모델에 의해 계산된 결과와 비교하였다. 엑스선 관전압은 50, 60, 80, 100, 110 kV 였다. 검출기로는 카드뮴 텔루라이드와 비정질 셀레늄 물질을 사용하였다. 엑스선 에너지 스펙트럼의 시뮬레이션 결과는 참조 결과와 일치하였고, NRMSD 값은 최소 1.1%에서 최대 5.7%를 보였다. 시뮬레이션 결과에 의하면 진단 영상을 획득할 때 적절한 관전압의 선택을 가능하게 할 것이다. 또한, 영상 획득 전 환자에 전달되는 선량을 예측하는데 기여할 것이다. Most diagnostic devices in the medical field use X-ray sources, which emit energy spectra. In radiological diagnosis, the quantitative and qualitative analyses of X-rays are essential for maintaining the image quality and minimizing the radiation dose to patients. This work aims to obtain the X-ray energy spectra used in diagnostic imaging by Monte Carlo simulation. Various X-ray spectra are simulated using a Monte Carlo simulation tool. These spectra are then compared to the reference data obtained with a tungsten anode spectral model using the interpolating polynomial (TASMIP) code. The X-ray tube voltages used are 50, 60, 80, 100, and 110 kV, respectively. CdTe and a-Se detector are used as the detectors for obtaining the X-ray spectra. Simulation results demonstrate that the various X-ray spectra are well matched with the reference data. Based on the simulation results, an appropriate X-ray spectrum, in accordance with the tube voltage, can be selected when generating an image for diagnostic imaging. The dose to be delivered to the patient can be predicted prior to examination in the diagnostic field.

GATE 시뮬레이션 프로그램을 이용한 I-131의 영상 특성의 타당성에 관한 연구

백철하(Cheol-Ha Baek),김대호(Dae Ho Kim),이용구(Yong-Gu Lee),이영진(Youngjin Lee) 대한전자공학회 2017 전자공학회논문지 Vol.54 No.5

본 연구의 목적은 GATE (Geant4 Application for Tomographic Emission) Simulation을 사용하여 치료용 방사성동위원소인 I-131의 감마카메라/SPECT 영상을 획득하여, 실제 기기의 실험결과와 그 특성을 비교 및 분석 하여 GATE simulation의 정확성을 획득하는 것이다. 더 나아가 GATE simulation을 이용한 치료용 방사성동위원소를 위한 감마카메라/SPECT 영상 정량화 기반기술 연구가 가능함을 입증하고자 한다. 본 연구에서 Simulation상에서 구성한 SPECT System은 Stream-R Forte version 1.2 (Philips Medical System, Best and Heerlen, Netherlands)의 설계변수를 참고로 하였다. 감마카메라/SPECT 시스템에서의 I-131 영상특성을 이해하기 위하여 실제 Forte 시스템을 이용하여 산란물질을 사용하였을 때와 사용하지 않았을 때 에너지 스펙트럼 및 선 선원에 대한 선 응답함수 (Line Spread Function, LSF)와 반치폭 (Full Width at Half Maximum, FWHM)을 측정하였다. 또한 실제 실험과의 비교를 위하여 GATE simulation에서 구성한 시스템에서도 동일한 실험 조건 및 변수에 대하여 에너지 스펙트럼 및 선 선원에 대한 LSF 및 FWHM을 측정하였다. 그 결과 산란물질을 사용하지 않았을 때의 에너지 스펙트럼의 경우 실제 실험과 Simulation 모두 364 keV의 위치에서 에너지 피크를 나타내어 동일한 경향의 결과를 보였다. FWHM은 실제 실험과 Simulation 모두에서 선원과 검출기간의 거리가 증가함에 따라 그 크기가 증가하는 경향을 보였으며 오차율은 3.8%로 나타났다. 산란물질을 사용하였을 때의 에너지 스펙트럼 역시 실제 실험과 Simulation 경우 모두에서 비슷한 경향을 나타내었다. 결론적으로, GATE simulation은 치료용 방사성 동위원소에 대해서도 실제 기기의 특성 및 방사성 동위원소의 특징을 모두 반영하고 있으며 이를 이용하여 감마카메라/SPECT에서의 치료용 방사성 동위원소의 정량화에 대한 다양한 연구가 가능 할 것이라고 사료된다. The purpose of this study was to validate for GATE (Geant4 Application for Tomographic Emission) simulation by comparing the results of GATE simulation and experiment in real SPECT system. Futhermore, we want to prove that it is possible that the quantitative research of gamma camera/SPECT imaging for therapeutic radio isotope by using GATE simulation. In this study, the SPECT system on simulation referred to the parameters of Stream-R Forte version 1.2 (Philips Medical System, Best and Heerlen, Netherlands). To understand the I-131 image of gamma camera/SPECT system, we acquired the energy spectrum and measured the full width at half maximum (FWHM) which comes from line spread function (LSF) with and without scatter material in real SPECT system. And to compare with experiment, we also measured the FWHM and acquired the energy spectrum without scatter material in GATE simulation. As a result, without scatter material, the energy peak was almost same location, which are located nearby 364 keV, and other spectrum factors are same tendency in both cases. The FWHM was increased by increasing the distance of source to detector, and the error rate was approximately 3.8%. When we used the line source with scatter material, energy spectrum also indicated similar tendency in both cases. As you confirmed earlier, GATE simulation included real instrument and radioisotope characters for therapeutic radioisotope. Therefore this result that it was possible that various quantitative study for therapeutic radioisotope imaging in gamma camera/SPECT using GATE simulation.