청도 반시의 노래 - 꽃나무의 전언 14

류영환 문예운동사 2010 문예운동 Vol.- No.108

서울시 종합의료기관의 실내공기 중 대기로 방출되는 라돈 (222Rn) 농도 측정 및 개선 방안

류영환,이수형,김미영,곽종길,동경래 (사)한국방사선산업학회 2018 방사선산업학회지 Vol.12 No.2

We have started this study in an attempt to measure facility spaces’ Radon density and minimize Radon damages to human health accounting for measurement values. The subject of this study is a general hospital situated within the Seoul metropolitan area, the Seoul Medical Center. The Radon density measurement points were dispersed as following for comparison among spatial categorization: 17 spots within office areas (places where only hospital employees occupy), 25 spots within patients’ waiting area (occupied by employees, patients, patient caretakers, general passerby), 22 spots within treatment areas (occupied by employees or patients). For comparison among building levels, 10 places were picked within the basement area (5 on the first basement level, 1 on the second basement level, 2 on the third basement level, 2 on the fourth basement level), 54 places above ground (25 on the first floor, 27 on the second, 2 on the third). For comparison based on the factor of window existence, 21 spots without windows and 43 spots with windows were compared. Measurement was carried out for the duration of four months by Alpha track detectors with the removal of LR-115 tapes. These detectors are fixed to the wall with a one meter length string hanging from a half-circle shaped link fixed upright at a right angle on the ceiling at the center of the measurement area. As a manual detector, for Alpha track detector measurement to be properly conducted, it should be used under minimized circumstantial changes from the usual status quo for the duration of measurement. Study collaborators have kept the environmental factors constant while measuring Radon density, with indoors detectors being comprised of two types, passive and active detectors. These two types could be differentiated apart by their electric power source. Passive detectors are easier to maneuver and are more economical in their costs than their active counterparts. Few demerits persist, however, in that passive detectors have more difficulty achieving prompt long term measurements and are more prone to lowered reliability in their measurements due to external environmental factors. Despite these shortcomings, for its relative low costs and efficiency, collaborators have decided on using Alpha track detector LR-115 device for the purpose of this study. The mean Radon concentration level of the 21 places with windows was 58.00 Bq·m-3, with the 43 places without windows mean level being 62.93 Bq·m-3, The mean difference of approximately 5 Bq·m-3 with windowed places being lower in Radon concentration levels were nonsignifican t (p>0.05). The reason why lower Radon density was measured in windowed areas could be postulated to be due to airing and emission of Radon from measured indoors to outdoors. In the comparisons between workspace categorizations, the mean Radon density level of the 17 places within office areas (occupied only by hospital employees) was 58.18 Bq·m-3, a mean of 64.50 Bq·m-3 in 22 patient waiting areas (occupied by employees, patients, caretakers, and passersby), and a mean of 61.31 Bq·m-3 was achieved in 22 treatment areas. Radon density level was ranked from highest to lowest from office areas, treatment areas, and patient waiting areas. There were, however, no statistical significance achieved among the three spatial categorizations (p>0.05). We could postulate lower Radon level was achievable through frequent airing from multiple windows. Comparisons between floor levels led to the result of mean of 55.90 Bq·m-3 in the 10 areas in the basement levels, and mean of 62.31 Bq·m-3 in the 54 areas in the above ground level floors. While not achieving statistical significance (p>0.05), Radon levels were measured to be 7 Bq·m-3 lower in the basement areas compared to the above ground levels. Based on these results, we believe reducing lung cancer inducing Radon density by appropriately measuring and controlling radon concentration levels would be condu...

Digital X-ray장비 구축 검진차량의 웹 기반 무선 네트워크 환경 구축 전과 후의 비교분석

류영환,권대철,구은회,동경래,최성현,장영일,Ryu, Young-Hwan,Kweon, Dae-Cheol,Goo, Eun-Hoe,Dong, Kyung-Rae,Choi, Sung-Hyun,Jang, Young-Ill 대한디지털의료영상학회 2010 대한디지털의료영상학회논문지 Vol.12 No.2

A total of 200 hospital employees participated in this study from January 2009 to June 2010. For the survey, each participant was given necessary items for external health exams. Cronbach's alpha was calculated for the survey regarding wireless networks. There was a need for educating data processing workers in the medical field regarding fundamental information prior to wireless network construction. The reason is high scores would be collected, which would reflect knowledge regarding data processing used at hospitals and the differences between paper charts and electronic charts. However, low scores were obtained which reflected knowledge regarding the differences between wired and wireless networks and Mini-PACS. Time for each patient was shortened to a maximum of three minutes and minimum of one minute for treatment and transmitting medical images when comparing pre and post wireless network construction(p < 0.01). Scores from the pre and post construction survey increase 1.98, 1.65, and 1.43 points for activity in the health screening area, usage of space in the health screening vehicle, and patient information storage respectively(p < 0.05). The number of patients receiving external health screenings twelve times was 3,655 prior to construction of a wireless network system. However, the number increased to 4,265 after construction. The increasing percentage was 17% in total. Prior to construction, X-ray images were taken 527 times, but after construction of a wireless network, this number growed to 1,194 and it was 116% increase. The loss of patient's medical treatment charts was reduced from 19.8% to 18.7% after construction. We believe that educating medical workers on Mini-PACS and Mini-OCS Systems will not only increase their efficiency but also make patients receiving better treatment.

Moyamoya 질환에서 1차 통과기법을 이용한 자기공명관류영상의 이해

류영환,구은회,정재은,동경래,최성현,이재승,Ryu, Young-Hwan,Goo, Eun-Hoe,Jung, Jae-Eun,Dong, Kyung-Rae,Choi, Sung-Hyun,Lee, Jae-Seung 대한디지털의료영상학회 2010 대한디지털의료영상학회논문지 Vol.12 No.1

The purpose of this study was to investigated the usefulness of MR perfusion image comparing with SPECT image. A total of pediatric 30 patients(average age : 7.8) with Moyamoya disease were performed MR Perfusion with 32 channel body coil at 3T from March 01, 2010 to June 10, 2010. The MRI sequences and parameters were as followed : gradient Echo-planar imaging(EPI), TR/TE : 2000ms/50ms, FA : $90^{\circ}$, FOV : $240{\times}240$, Matrix : $128{\times}128$, Thickness : 5mm, Gap : 1.5mm. Images were obtained contrast agent administrated at a rate of 1mL/sec after scan start 10s with a total of slice 1000 images(50 phase/1 slice). It was measured with visual color image and digitize data using MRDx software(IDL version 6.2) and also, it was compared of measurement with values of normal and abnormal ratio to analyze hemodynamic change, and a comparison between perfusion MR with technique using Warm Color at SPECT examination. On MR perfusion examination, the color images from abnormal region to the red collar with rCBV(relative cerebral blood volume) and rCBF(relative cerebral blood flow) caused by increase cerebral blood flow with brain vascular occlusion in surrounding collateral circulation advancement, the blood speed relatively was depicted slowly with blue in MTT(Mean Transit Time) and TTP(Time to Peak) images. The region which was visible abnormally from MR perfusion examination visually were detected as comparison with the same SPECT examination region, would be able to confirm the identical results in MMD(Moyamoya disease)judgments. Hymo-dynamic change in MR perfusion examination produced by increase and delay cerebral blood flow. This change with digitize data and being color imaging makes enable to distinguish between normal and abnormal area. Relatively, MR perfusion examination compared with SPECT examination could bring an excellent image with spatial resolution without radiation expose.

인간사막 외 1편

류영환 천년의시작 2017 (계간)시작 Vol.16 No.4

돌아오지 못한 편지 외 1편

류영환 천년의시작 2016 (계간)시작 Vol.15 No.4

핵의학과 방사선작업종사자의 말단 및 수정체 선량에 대한 인식도 조사

류영환 ( Younghwan Ryu ),서민영 ( Minyoung Seo ),동경래 ( Kyungrae Dong ) 조선대학교 공학기술연구원 2015 공학기술논문지 Vol.8 No.3

Radiation workers working in nuclear medicine department are exposed to radiation, especially in extremities and the eye lens, due to their work consisting of distributing radioactive isotopes and injecting patients with the radiological materials. The assessment of radiological exposure to the extremities and the eye lens using whole body effective dose assessment method cannot be deemed valid; Because the extremities and the eye lens cannot be constantly protected, there needs to be another dose assessment method. Despite the apparent error in the current assessment method, radiation workers in nuclear medicine department overlook exposure to radiation in the extremities and the eye lens, leading to the current lack of exposure dose control. As such, we set out to understand the radiation workers’ level of knowledge and awareness in this issue by surveying 33 radiation workers working in Korean nuclear medicine department. As for the level of knowledge about the dosimeter for extremities and the eye lens, most radiation workers were aware that radiation exposure in the extremities and the eye lens took place during their work, as well as yearly exposure dose limit, but they were not as knowledgeable about the dosimeter. In the assessment of the radiation workers’ awareness of dosimeter, these professionals acknowledged the necessity of wearing a dosimeter to manage the exposure dose in the extremities and the eye lens, although their level of understanding and trust for these products were rather low. In the current usage of dosimeters in nuclear medicine department, it was revealed that most radiation workers do not wear dosimeters during their work, which led to the lack of exposure dose assessment during distribution and injection tasks. As such, the current study concludes that policies on exposure dose measurement and assessment are required to optimize the amount of exposure to the extremities and the eye lens in radiation workers, in addition to continued education and training to change awareness about controlling the exposure dose.

방사선의 산업적 이용에 따른 방사선 안전관리 지식 조사

류영환(Younghwan Ryu),동경래(Kyungrae Dong),정운관(Woonkwan Chung),조재환(Jaehwan Cho),박용순(Yongsoon Park),정홍량(Hongryang Jung) 한국방사선학회 2012 한국방사선학회 논문지 Vol.6 No.3

본 연구의 목적은 방사선의 사업적 이용에 따른 방사선발생장치 또는 방사성동위원소 등(이하 방사성동위원소 등)을 운용하는 방사선작업종사자를 대상으로 방사선안전관리와 관련된 지식의 설문 조사하고 이를 체계적으로 추이분석 함으로서 방사선 이용시설 등의 방사선안전 문화를 정착시키기 위함에 있다. 연구 방법은 2011년 08월 01일 부터 09월 05일 까지 861 명의 방사선 종사자를 대상으로 설문 조사를 하였다. 분석 방법으로 설문 응답자의 일반적인 특성과 기관정보는 빈도 분석을 하였으며 방사선안전관리에 대한 지식 수준은 평균과 표준편차를 구하여 각각 비교하였다. 분석 결과 작업 종사자의 방사선 안전 관리에 대한 지식 조사에서는 종사자 모두 높은 수준으로 평가 되었다. 결론적으로 방사선 작업종사자들의 방사선 안전관리와 관련하여 보다 다양한 요인들에 대한 연구들이 수행되어야 하며 작업종사자들의 의식을 높이기 위해서 시기적절한 교육이 필요할 것으로 사료되며, 지속적으로 방사선 작업종사자들을 관리함으로써 효율적인 방사선이용이 될 수 있는 기반이 확립될 것으로 사료된다. The purpose of this study was examine via a survey the knowledge related to radiation safety management (RSM) among radiation workers who operated or used a radiation generator or radioactive isotopes (radioactive isotopes, etc. hereinafter) for industrial use and to systematically analyze the changes in the survey results in order to promote a radiation safety culture for facilities where radiation is used. We administered a questionnaire to 861 radiation workers in the period from August 1 to September 5, 2011. As for the analysis method, a frequency analysis was made for the general characteristics and organization information of survey respondents, while the average and standard deviation were calculated and compared for the knowledge level of the RSM. According to the analysis results, the knowledge level of the RSM was evaluated to be high in all of the radiation workers. In conclusion, it is required to conduct a study on various factors in regards to the RSM among radiation workers. This can contribute to establishing educational programs in a timely manner to increase the awareness of safe and efficient use of radioactive materials and equipments by radiation workers.

소아 복부 및 골반 X선 검사 시 나노텅스텐 차폐체의 선량평가에 관한 연구

최성현,류영환 (사)한국방사선산업학회 2020 방사선산업학회지 Vol.14 No.4

A shield made of nano-sized tungsten particles was fabricated using eco-friendlymaterials to protect organs and gonads in the abdomen of children who are sensitive to abdominaland pelvic X-ray examination. We would like to evaluate its usefulness through dose evaluation. During the abdominal and pelvic X-ray examination of children, there was a dose reduction ofabout 60% in ESD values before and after the use of the shield. If the Nano Tungsten shield iscommercialized and used, it is believed that exposure doses for pediatric patients’ radiation-relatedtests such as general X-ray imaging, CT examination, and fluoroscopic examination can be reduced.

SNR and PSNR measurements and analysis of median filtering for the removal of impulse noise from CR imaging

홍성일,류영환,동경래 한국콘텐츠학회 2009 International Journal of Contents Vol.5 No.4

In this paper, the authors showed that the removal of impulse noise in CR images was implemented using variety of median filters and SNR/PSNR measurements. They used three kinds of medical images-hand, skull, and knee- for experimental results. But the noise in CR image was only the impulse noise. In real medical image, the noise of an image would be very different type. Therefore, the lack of experimental results using different noise in CR images is one flaw.