The Efficiency of Radiation Shielding Sheet to Reduce Radiation Exposure during C-arm Fluoroscopy

전호상,신원철,설희윤,기용간,김경백,추기석,이상돈,강석웅 대한골절학회 2023 대한골절학회지 Vol.36 No.4

Purpose: This study evaluates the radiation shielding performance of a new lead-free tungsten-based sheet to reduce the radiation exposure of operators and patients under C-arm fluoroscopy. Materials and Methods: A non-lead radiation shielding sheet (ROO201128; Pentas, Korea) was fabricated using tungsten and bismuth. The dose measurements were conducted using a C-arm fluoroscopy machine at 64 kVp and 1.5 mA, assuming two possible scenarios according to the position of the sheet. In each scenario, measurements were conducted at three distances (30, 60, and 90 cm) away from the beam center and in three directions (cephal, caudal, and operator’s direction). Results: In the area within a radius of 60 cm from the beam center, the measured doses were reduced by 66.3% on mean, and the doses measured at distances more than 60 cm were less than 0.1 mSv/h in both scenarios. The most beneficial utilization of the lead-free shielding sheet was verified during Carm fluoroscopy by placing the sheet on the X-ray tube. The operator’s radiation exposure was reduced by 56.6% when the sheet was placed under the phantom, and by 81.0% when the sheet was placed on the X-ray tube. Conclusion: The use of lead-free radiation shielding sheets under C-arm fluoroscopy was effective in reducing radiation exposure, and the most beneficial scenario in which the sheet can be utilized was verified when the sheet was placed on the X-ray tube.

A군 연구균 감염 후 급성 사구체 신염과 동반된 침습성 수막구균감염증 1례

전호상,한원호,박동균,차성호,Jeon, Hosang,Hahn, Wonho,Park, Dongkyun,Cha, Sungho 대한소아감염학회 2004 Pediatric Infection and Vaccine Vol.11 No.1

본 저자들은 A군 연쇄구균 감염 후 급성 사구체신염과 동반된 수막구균감염증(수막구균 뇌수막염, 수막구균혈증)에 걸린 7세 남아를 경험하였는데 A군 연쇄구균 감염 후 급성 사구체 신염으로 인해서 C3가 감소하여 수막구균감염증에 감염이 되었는지, 역으로 가능성은 떨어지지만 수막구균감염증의 결과로 C3가 감소하였고 사구체신염이 생긴 것인지 전후 관계가 확실하지 않은 증례를 문헌고찰과 함께 보고하는 바이다. Neisseria meningitidis is a leading cause of meningitis and septicemia in children and young adults. Meningococcemia, the most severe form of infection, represents a part of the various spectrum of the illness, and its clinical manifestations varied from mild fever and occult bacteriemia to fulminant catastrophic events(e.g., sepsis, shock, and death) within a few hours after onset of symptoms. Complement deficiencies, either congenital or acqired, increase the risk for invasive meningococcal disease. Since C3 plays a critical role in the complement cascade, congenital C3 deficiency or conditions that decrease C3(e.g., systemic lupus erythematosus, cirrhosis, nephritis, C3 nephritic factor) increase the risk for invasive disease due to pyogenic bacteria including N. meningitidis. We had experienced a case of meningococcemia and meningococcal meningitis presenting with mild fever, petechiae, and purpura. The patient was a 7-year old male. He had mild fever, vomiting, headache, nuchal rigidity, petechiae and purpura on both lower extremities, which spreaded to the whole body. His blood culture grew Neisseria meningitidis. The diagnosis of meningococcal meningitis was confirmed by examination of cerebrospinal fluid. The clinical symptoms of the illness were improved after treatment of antibiotics(cefotaxime) for 12 days. However the patient had developed generalized edema, microscopic hematuria & proteinuria on the third day after admission. High ASO titer and low serum C3 level were also noted. The microscopic hematuria returned to normal about 2 months after discharge. The C3 level returned to normal range about 3~4 months after discharge. we report a case of combined acute poststreptococcal glomerulonephritis and acute invasive meningococcal disease with reference review.

유리선량계의 전처리 방법이 방사선 치료 선량 측정에 미치는 영향

전호상,남지호,박달,김용호,김원택,김동원,기용간,김동현,이주혜,Jeon, Hosang,Nam, Jiho,Park, Dahl,Kim, Yong Ho,Kim, Wontaek,Kim, Dongwon,Ki, Yongkan,Kim, Donghyun,Lee, Ju Hye 한국의학물리학회 2013 의학물리 Vol.24 No.2

여러 치료선량 측정기들 중 치료 현장에서의 사용이 간편한 형광물질 기반 측정기인 유리선량계(Glass Rod Dosimeter, GRD)는 방사선 조사 후 측정 소자의 안정화를 위한 전처리(Pre-processing) 과정이 필수적이며, 가열방식($70^{\circ}C$, 30분)과 대기방식($20^{\circ}C$, 24시간)의 두 가지의 전처리 방식이 사용되고 있다. 본 연구에서는 각각의 전처리 조건이 측정 결과에 미치는 영향을 분석하여 사용자들에게 유용한 참고자료를 제시하고자 한다. 20개의 GRD 소자들 모두에 같은 선량을 조사한 후, 10개씩 나누어 각각 다른 전처리 방식을 사용하여 판독함으로써 각 전처리 방식의 특징들을 상호 비교하였다. 가열방식의 경우 소자 간 판독 편차는 1.13%, 시간에 따른 평균 판독값의 편차는 최대 5.33%였다. 대기방식의 경우에는 소자 간 판독 편차가 0.49%, 시간에 따른 평균 판독값의 편차는 최대 1.28%로 나타났다. 또한 동일한 선량을 주었을 때 전처리 방식에 따라 판독 절대값은 4.1%의 차이를 보였다. 또한 251명의 환자들을 대상으로 한 임상 측정 평가 결과 부위에 따라 다르지만 평균적으로 5% 이내의 측정 오차를 보였으나, 대기 방식의 경우 판독 시점에 따른 영향이 상대적으로 크게 나타났다. 결론적으로 GRD는 치료 현장에서 사용하기에 적합하나 신속한 판독이 요구되지 않는다면 대기방식의 전처리가 보다 적합하며 정해진 판독 시점을 지켜야 한다. 또한 치료 부위 등 조사 조건의 변화에 관계없이 안정적인 정확성을 기대할 수 있는 측정 방법에 대한 연구가 향후 필요하다고 생각된다. The experimental verification of treatment planning on the treatment spot is the ultimate method to assure quality of radiotherapy, so in-vivo skin dose measurement is the essential procedure to confirm treatment dose. In this study, glass rod dosimeter (GRD), which is a kind of photo-luminescent based dosimeters, was studied to produce a guideline to use GRDs in vivo dosimetry for quality assurance of radiotherapy. The pre-processing procedure is essential to use GRDs. This is a heating operation for stabilization. Two kinds of pre-processing methods are recommended by manufacturer: a heating method (70 degree, 30 minutes) and a waiting method (room temperature, 24 hours). We equally irradiated 1.0 Gy to 20 GRD elements, and then different preprocessing were performed to 10 GRDs each. In heating method, reading deviation of GRDs at same time were relatively high, but the deviation was very low as time went on. In waiting method, the deviation among GRDs was low, but the deviation was relatively high as time went on. The meaningful difference was found between mean reading values of two pre-processing methods. Both methods present mean dose deviation under 5%, but the relatively high effect by reading time was observed in waiting method. Finally, GRD is best to perform in-vivo dosimetry in the viewpoint of accuracy and efficiency, and the understanding of how pre-processing affect the accuracy is asked to perform most accurate in-vivo dosimetry. The further study is asked to acquire more stable accuracy in spite of different irradiation conditions for GRD usage.

2003~2004년 경남 마산 지역에서 분리된 A군 연쇄구균의 T 혈청형과 emm 유전자형의 계절별 분포

전호상,박화진,이희주,마상혁,차성호,Jeon, Ho-Sang,Park, Hwa-Jin,Lee, Hee-Joo,Ma, Sang-Hyuk,Cha, Sung-Ho 대한소아감염학회 2005 Pediatric Infection and Vaccine Vol.12 No.1

목 적 : 류마티스열이나 사구체신염과 같은 합병증의 집단발생 및 GAS 감염의 역학조사를 위해서는 감염균의 혈청형분석이 필수적이다. T 단백은 GAS의 역학적 상황을 이용하는데 유용하여 선별검사로 가장 많이 이용한다. 혈청형 검사의 단점을 보완하기 위해 최근 분자생물학적 방법을 이용하기 시작하였다. 중합효소연쇄반응으로 emm 유전자를 증폭하여 자동염기서열 분석기를 이용한 emm형별 분석이 최근에 보고가 되고 있다. 그래서 저자들은 emm 유전자를 이용한 자동염기서열 분석과 T 혈청학적 분석을 통하여 마산의 어느 한 센터에서 얻은 GAS의 계절별 분포에 대해서 알고자 하였다. 방 법 : 2003년 6월부터 2004년 2월까지 경남 마산시에 위치한 창원파티마병원에서 급성 인두염이나 성홍열 또는 봉소염이 의심되는 환아에게 인후배양을 시행하였고, 그 중 GAS로 동정된 100개의 균주를 분리하여 미국 미네소타대학의 WHO Collaborating Center on Group A Streptococci에 보내 T 항원형을 혈청학적 동정을 하였고 emm 유전자 분석을 하였다. 이 결과들을 다시 계절별과 질병별로 분류하였다. 결 과 : T단백 혈청형은 총 19종이 분리되었다. 계절별로 분류하면 여름철에는 빈도순으로 T4(27.5%), T1(17.6%), T6(13.7%), T12(13.7%)이 흔히 분리되었고, 겨울철에는 T4(28.3%), T12(15.2%), T12/B3264(8.7%)의 순서로 흔히 발생하였다. T4, T12는 계절별로 변화가 거의 없었다. 질환별로 분리하면 급성 인두염은 89례를 차지하였는데 T 혈청형을 빈도순으로 나열하면 계절별 분포에서와 마찬가지로 T4(26.7%), T12(14.0%), T1(12.8%), T6(11.6%) 순으로 전체 균주의 빈도순과 동일한 양상을 보였다. emm 유전자형은 총 15종류가 분류되었다. emm 1, emm 6, emm 9, emm 44는 겨울철에 많이 감소하거나 없어졌고, emm 3, emm 12, emm 89는 겨울철에 새로 생기거나 빈도가 비교적 많이 증가한 유전자형이었다. 급성 인두염에서 emm 유전자형을 빈도순으로 나열하면 계절별 분포에서와 마찬가지로 emm 4(26.7%), emm 22(18.6%), emm 1(12.8%), emm 6(11.6%)의 순서로 분리되었다. 결 론 : 2003년과 2004년에 걸쳐 조사한 T단백 혈청형과 emm 유전자형의 계절별 분포는 각각 19종과 15종으로 다양하게 분리되었다. 이 중 EM 내성과 관련이 있는 T 혈청형으로는 T12, T28, T4, T1, NT 등으로 알려져 있는데 이들의 비율이 전체의 56.7%를 차지하였다. 따라서 항생제 선택에 있어서 EM 내성률이 높다는 사실을 고려해야 한다. T 혈청형과 emm 유전자형의 분석이 GAS 질병의 역학과 병인을 연구하는데 도움이 되므로 앞으로 매년 감시를 해야하고, 특히 침습성 연쇄구균 감염으로부터 얻은 GAS을 T 혈청형 분석과 emm 유전자형 분석을 통해서 감시해야 하겠다. Purpose : The aim of this study is to know seasonal distribution of group A streptococci obtained from one center using emm genotyping and T serotyping in Masan from 2003 through 2004. Methods : Among children who visited the Changwon Fatima Hospital at Masan, Korea from June 2003 through February 2004, 100 patients who had clinical findings of acute pharyngitis, scarlet fever, and cellulitis were confirmed as GAS by culture, and were enrolled in our study. All obtained GAS were sent to the WHO Collaborative Center for Reference and Research on Streptococci, University of Minnesota, Minneapolis for T serotyping and emm genotyping. We classified these results again according to seasonal and disease's entities. Results : 19 different T serotypes was typed. T4(27.5%), T1(17.6%), T6(13.7%), and T12(13.7%) serotypes were relatively common in summer, while T4(28.3%), T12(15.2%), and T12/B3264(8.7%) were common in winter. T4 and T12 were persistent all year around. Distribution of T serotypes in 89 patients with pharyngotonsillitis were T4(26.7%), T12(14.0%), T1(12.8%), and T6(11.6%) in order of frequency. 15 different emm genotypes was typed. The number of emm 1, emm 6, emm 9, and emm 44 genotypes decreased or disappeared in winter, and the number of emm 3, emm 12, and emm 89 genotypes increased or reappeared in winter. Conclusion : Because T serotyping and emm genotyping are useful tools for evaluating epidemiology and pathogenesis of group A streptococci, we should monitor these strains every year, and should serotype and genotype GAS obtained from the invasive streptococcal infections.

소아 천식

전호상 한국의학사 2004 診斷과治療 Vol.24 No.1

수몰된 종족마을의 건축ㆍ문화적 지속성에 관한 연구 : 경북 구미시 해평면 일선리마을의 사례를 중심으로 Focused on the Case of a Newly Resettled Lineage Village, Ilseon-ri Village, Kyongsanbuk-do

전호상,이상해 대한건축학회 2004 대한건축학회논문집 Vol.20 No.2

This study is on the architectural and cultural continuity caused by the resettlement of a village, Ilseon-ri, after submergence. The villagers of Ilseon-ri originally resided in Musil, Imdong-myun, Andong-si, Kyongsangbuk-do and they were forced to move to other place caused by the construction of the lmha dam near Musil. Since then, the villagers decided to construct a new village, Ilseon-ri, Haepyong-myun, Kumi-si, Kyongsangbuk-do in 1987, about 70km south-west distant from Musil. Through the study, it is verified that the newly built village demonstrates an alternative method of establishing a contemporary lineage village by following characteristics of traditional lineage villages in Korea such as 1). social and cultural norms adopted from Confucian order and traditional life, 2). allocation of important buildings in a village such as Jong-taeck(종택), Jeong-ja(정자), Village-hall(마을회관), etc, showing their hierarchy in a village. It is also verified that plans of newly built modern western style houses reflect traditional housing plan and space use by separating man and woman in house, and by proving reception area for guests. Thus, it can be maintained that Ilseon-ri, a resettled lineage village, shows a case of keeping architectural and cultural continuity in Korea.

Imaging Responses of On-site CsI and Gd2O2S Flat-panel Detectors: Dependence on the Tube Voltage

전호상,정명진,윤승만,남지호,이자영,박달,김원택,기용간,김호경 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.1

One of the emerging issues in radiography is low-dose imaging to minimize patient’s exposure. The scintillating materials employed in most indirect flat-panel detectors show a drastic change of X-ray photon absorption efficiency around their K-edge energies that consequently affects image quality. Using various tube voltages, we investigated the imaging performance of most popular scintillators: cesium iodide (CsI) and gadolinium oxysulfide (Gd2O2S). The integrated detective quantum efficiencies (iDQE) of four detectors installed in the same hospital were evaluated according to the standardized procedure IEC 62220-1 at tube voltages of 40 − 120 kVp. The iDQE values of the Gd2O2S detectors were normalized by those of CsI detectors to exclude the effects of image postprocessing. The contrast-to-noise ratios (CNR) were also evaluated by using an anthropomorphic chest phantom. The iDQE of the CsI detector outperformed that of the Gd2O2S detector over all tube voltages. Moreover, we noted that the iDQE of the Gd2O2S detectors quickly rolled off with decreasing tube voltage under 70 kVp. The CNRs of the two scintillators were similar at 120 kVp. At 60 kVp, however, the CNR of Gd2O2S was about half that of CsI. Compared to the Gd2O2S detectors, variations in the DQE performance of the CsI detectors were relatively immune to variations in the applied tube voltages. Therefore, we claim that Gd2O2S detectors are inappropriate for use in low-tube-voltage imaging (e.g., extremities and pediatrics) with low patient exposure.

선형가속기 방사선 중심점의 크기 측정 방법 개발과 Clinac 21EX 선형가속기의 방사선 중심점 크기 분석

전호상,남지호,박달,김용호,김원택,김동원,기용간,김동현,Jeon, Ho-Sang,Nam, Ji-Ho,Park, Dahl,Kim, Yong-Ho,Kim, Won-Taek,Kim, Dong-Won,Ki, Yong-Kan,Kim, Dong-Hyun 한국의학물리학회 2011 의학물리 Vol.22 No.3

Star-shot 영상을 이용한 선형가속기의 방사선중심점(radiation isocenter)에 대한 정도관리를 정량적으로 할 수 있는 방법을 개발하고 이를 컴퓨터 프로그램으로 구현하였다. 구현한 프로그램의 정확도를 검증하고 프로그램을 사용하여 2008년 6월부터 2010년 12월 사이에 수행한 선형가속기 Clinac 21EX (Varian, USA)의 방사선중심점의 정도관리 정보로부터 방사선중심점의 크기를 측정하여 어떤 변화가 있는지 분석하였다. 개발한 방법은 먼저 star-shot 영상의 빔(ray)들 각각의 중심선 위에 있는 두 개의 점들을 찾아서 모든 중심선들의 방정식을 구하고 구한 방정식을 이용하여 중심선들을 모두 가로지르는 원의 최소의 직경을 찾아 방사선중심점의 크기를 구하는 것이다. 프로그램은 중심선의 x-절편과 y-절편을 0.084 mm 이하의 정확도로 찾아냈고 방사선중심점의 크기는 0.053 mm의 정확도로 구하여 검증에 사용한 영상의 해상도 0.085 mm보다 작았다. Clinac 21EX의 radiation isocenter의 크기는 콜리메이터, 갠트리, 테이블 각각 $0.33{\pm}0.27mm$, $0.71{\pm}0.36mm$, $0.50{\pm}0.16mm$였고 측정 기간 동안 2.0 mm보다 작게 나와 모두 허용한도를 만족하였다. 개발한 프로그램은 충분한 정확도로 방사선중심점의 크기를 계산해주어 정기적인 정도관리에 많은 도움이 될 것으로 생각된다. A method to get a size of the radiation isocenter of linear accelerators using star-shot images was presented and a computer program was developed to automate the method. Accuracy of the method was verified. The developed program was used to measure sizes of the radiation isocenters for a Clinac 21EX (Varian, USA) using data of quality assurance (QA) performed from June 2008 to December 2010. To calculated the size of radiation isocenter, positions of two points on each central ray of the star-shot image were found and the equation of the central ray was determined using the positions of two points. Using the equations of central rays the radius of the minimum circle intersecting all the central rays, which is one half of the size of radiation isocenter, was calculated. The program measured x-intercepts and y-intercepts of the central rays within errors of 0.084 mm and sizes of radiation isocenters within 0.053 mm. All the errors were less than the spatial resolution of star-shot images 0.085 mm. The radiation isocenter sizes of Clinac 21EX were $0.33{\pm}0.27mm$, $0.71{\pm}0.36mm$, $0.50{\pm}0.16mm$ for collimator, gantry and couch respectively. During the measurement period all the measured sizes were less than 2.0 mm and within tolerance. The developed program could calculate the size of radiation isocenters and it would be helpful to routine QA.

산란선 대 일차선비(SPR)를 이용한 MV 영상의 산란 보정을 위한 실험적 방법

전호상,박달,이자영,남지호,김원택,기용간,김동현,이주혜,김동원,Jeon, Hosang,Park, Dahl,Lee, Jayeong,Nam, Jiho,Kim, Wontaek,Ki, Yongkan,Kim, Donghyun,Lee, Ju Hye,Kim, Dongwon 한국의학물리학회 2014 의학물리 Vol.25 No.3

고에너지(MV, Mega-voltage) X선 영상은 일반적인 방사선 치료 시 조사야의 영상 검증이 가능한 유일한 방법으로 널리 사용되고 있다. 그러나 고에너지 특유의 높은 콤프턴 산란 반응 특성으로 인해 저에너지 영상에 비해 화질이 크게 낮으며, 1990년대에 디지털 MV 영상이 소개된 이후 화질을 보완하기 위한 연구들이 활발히 이루어져 왔다. 본 연구에서는 디지털 영상처리 기법을 이용하거나 산란 커널 계산을 통해 화질을 개선하는 기존의 방법 대신 측정된 산란선 대 일차 선비(SPR, Scatter to Primary Ratio)를 이용하는 새로운 방법을 제안하였다. 먼저 주어진 촬영 조건 하에서 환자를 모사하는 고체 물팬톰의 유무에 따라 각각 MV영상을 촬영하고 방사선의 투과율을 별도로 계산한 후 산란 성분이 포함된 일차선 영상과 포함되지 않은 일차선 영상을 각각 획득하였다. 이를 기반으로 산란 보정에 사용할 SPR 분포를 획득하였다. 그리고 알루미늄 막대를 이용한 line pair (LP) 팬텀 및 실제 환자 골반의 영상을 이용하여 산란 보정 효과의 검증을 수행하였다. SPR 측정 결과 팬톰 두께에 따른 SPR 분포들을 성공적으로 획득하였으며, LP 팬텀 검증 결과 영상의 산란 성분이 효과적으로 제거되어 팬톰 본래의 밀도 분포가 복원되었음을 확인하였다. 또한 환자 골반 영상 보정 결과 모든 관심영역에서 대조도가 평균 48% 증가하였다. 본 연구에서 제시한 MV 영상의 산란 보정 방법은 실제 측정 자료를 기반으로 하므로 높은 신뢰성을 가지며, 적은 시간과 비용으로도 임상 현장에서 즉각적인 도입이 가능하다. 결론적으로 본 연구는 MV 영상을 이용한 영상유도 방사선치료의 질을 높이기 위한 하나의 효과적인 방법이 될 수 있을 것으로 기대된다. In general radiotherapy, mega-voltage (MV) x-ray images are widely used as the unique method to verify radio-therapeutic fields. But, the image quality of MV images is much lower than that of kilo-voltage x-ray images due to scatter interactions. Since 1990s, studies for the scatter correction have performed with digital-based MV imaging systems. In this study, a novel method for the scatter correction is suggested using scatter to primary ratio (SPR), instead of conventional methods such as digital image processing or scatter kernel calculations. We measured two MV images with and without a solid water phantom describing a patient body with given imaging conditions, and calculated un-attenuated ratios. Then, we obtained SPR distributions for the scatter correction. For experimental validation, a line-pair (LP) phantom using several Al bars and a clinical pelvis MV image was used. As the result, scatter signals of the LP phantom image were successfully reduced so that original density distribution of the phantom was restored. Moreover, image contrast values increased after SPR correction at all ROIs of the clinical image. The mean value of increases was 48%. The SPR correction method suggested in this study has high reliability because it is based on actually measured data. Also, this method can be easily adopted in clinics without additional cost. We expected that the SPR correction can be an effective method to improve the quality of MV image guided radiotherapy.

디지털 흉부 X선 촬영장치의 화질: 정량적 화질 평가와 영상의학과 의사의 육안 평가 간의 비교 연구

전호상,남지호,정명진,박달,김원택,김용호,기용간,김동현,이주헤,김동원 대한영상의학회 2011 대한영상의학회지 Vol.65 No.5

Purpose: To evaluate the performance of imaging devices, which should be periodically monitored to maintain high quality images to the radiologists. Additionally, this evaluation may prevent patients from radiation over-exposure. The most suitable engineering standard for imaging performance evaluation of digital X-ray thoracic imagers was determined. Materials and Methods: IEC 62220-1 standards were used to evaluate the performance of the imagers. In succession, the visibilities of overall image, pneumothorax, and humerus head in anthropomorphic thoracic phantom images were used to evaluate the image qualities by radiologists. Results: The rank correlation coefficient (p) of visual scoring by radiologists with system spatial resolution is not meaningful (p-value, p = 0.295), but is significant with image noise (p-value, p = -0.9267). Finally, the noise equivalent quanta (NEQ) presents a high rank correlation for visual scoring of radiologists (p-value, p = 0.9320). Conclusion: Image quality evaluation of radiologists were mainly affected by imaging noise. Hence, the engineered standard for evaluating image noise is the most important index to effectively monitor the performance of X-ray imagers. Additionally, the NEQ can be used to evaluate the performance of radiographic systems, because it theoretically corresponds to the synthetic image quality of systems.