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RISS 인기검색어
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- 저자 : 오용운(Yong Woon OH) (검색결과 3 건)
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심혈관 CT 검사 시 적응식 통계적 반복 재구성법(ASIR)에 대한 유용성
장현철(Hyun Chul Jang),조용근(Yong Geun Cho),오용운(Yong Woon OH),김진배(Jin Bae Kim),조인완(In Wan Cho),구상진(Sang Jin Gu),유병헌(Byeong Heon Yoo) 대한CT영상기술학회 2010 대한CT영상기술학회지 Vol.12 No.2
Purpose The goals of this study was to evaluate effect of reduced radiation dose, change of CT noise, and proper amount of ASIR under assessing image quality with different ASIR amounts during cardiovascular CT examinations. Materials and methods 15 patients who had undergone routine cardiac CT for evaluation of bean problem were enrolled and all examinations were performed on a 64-MDCT scanner (Light-Speed VCT XTe, GE Healthcare, Milwaukee, USA). The GE performance evaluation phantom was scanned triple and noise were measured at center(directions of 6 o’clock) and periphery (directions of 9, 12, 3 o’clock) of phantom image under fixed 100 kVp and during changing of ASIR 0~100%. The two radiologists estimated me subjective image qualities of right coronary artery(RCA), left circumflex artery(LCX), left anterior descending artery(LAD) in reconstructed four chamber images. To assess radiation dose, CTDIvols recorded from applied ASIR man non-applied ASIR were compared and analyzed. Results In applied ASIR to image in 10 % increments (0~100%), CT noise of center(directions of 6 o’clock) and periphery(directions of 9, 12, 3 o’clock) of phantom decreased in 9.7%~49.5%, 9.8%~52.1%, 9.6%~48.9%, 9.7%~51.1%. Observer A and B estimated image quality respectively as follows: 15 and 15 patients until 60% ASIR, 13 and 13 patients until 70% ASIR, 12 and 8 patients until 80% ASIR, 8 and 6 patients until 90% ASIR, 7 and 6 patients at 100% ASIR In assessing radiation dose, CIDIvol recorded from 60% ASIR decreased in 46.9% (21.11 mGy) than non-applied ASIR(39.73 mGy) Conclusion 60% ASIR helps reduce radiation dose and acquire consistent image quality without spoiling quality.
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경부 CT검사시 선속경화현상 감소를 위한 환자 자세 및 영상 평가
정우준(Woo Jun Jeong),신훈(Hoon Sin),오용운(Yong Woon Oh),김진배(Jin Bae Kim),조인완(In Wan Cho),구상진(Sang Jin Gu),유병헌(Byeong Heon Yoo) 대한CT영상기술학회 2009 대한CT영상기술학회지 Vol.11 No.1
Purpose The goals of this study was to examine the changes of beam hardening effect in shoulder and to evaluate the change of image quality which follows in positional change in patients with neck diseases. Materials and methods 30 patients with neck diseases were included in this study and 16-slice MDCT (Sensation 16, Siemens, Erlangen, Germany) was undergone. Positions of patients had changed with time such as neutral position with(group N), position with raising left arm (group S), and position with getting off everted both arms maximally(group P). ROI (1cm in area) located at supraclavicular fatty tissue for measuring CT noise was measured(3 times) and an average was recorded. For analysis of radiation exposure, parameters were fixed and scanned topograms of changed positions were compared with CTDIvol values measured at same position. Two investigators assessed image qualities, which were graded to unacceptable, suboptimal, adequate, good, excellent diagnostic quality. Results In CT noise, group S and group P showed 23% and 19% decrement rather than those of group N respectively. In radiation exposure, group S and group P showed 12% and 11% decrement rather than those of group N respectively. In 30 patients, image qualities of group N, group S, and group P were analyzed to unacceptable(n=0, 0, 0), suboptimal (n=0, 28, 2), adequate (n=24, 26, 3), good (N=28, 6, 22), and excellent diagnostic quality (n=8, 0, 33). Conclusion Appropriate positional change in neck CT scanning is useful method for obtaining images of improved quality and reducing beam hardening effect by shoulder.
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CT Mammography검사 시 자세변화에 따른 영상평가 및 적정선량에 관한 연구
송훈(Hoon Song),김현주(Hyeon Ju Kim),신훈(Hoon Shin),조인완(In Wan Cho),오용운(Yong Woon OH),유병헌(Byeong Heon Yoo),김승식(Seung Sik Kim) 대한CT영상기술학회 2008 대한CT영상기술학회지 Vol.10 No.1
Purpose The subject of this study is female breast cancer patient who had. CT mammography before and after surgery. The study covers effects on exposure dose and image quality by change of exposure condition are observed, and makes comparative, analytic study of difference between a breast image taken with supine position and the other one with prone position. Materials & Methods Qualities of supine position image were compared with those of prone position image and difference between two of the images were analyzed with change of kVp and mAs by 3grades(Equivalent, Acceptable, Unacceptable). A special equipment was used for prone position image so as to breast of the subjects don’t be squeezed. CTDIvol was recorded scanning by 120kVp/100mAs during usual scanning and 100kVp/70mAs for this study. 20 female breast cancer patients were subjects, and Somatom Sensation16(Siemens, Erlagen, Germany) was used by 2 observers in this study. Two studies were conducted on phantom. First, ion chambers were put into holes around and center of a phantom, and exposure dose on reader was recorded after scanning the phantom with change of kVp and mAs. Second, CTDIvol that was changing by exposed area differ by position of the breast phantom was measured with change of kVp and mAs, Results According to the 20 scanned images based on change of position and image quality, It gives 1 case on Equivalent, 19 cases on Acceptable and 0 case on Unacceptable. CTDIvol is measured as 7.8mGy at 120kVp/100mAs and 3.5mGy at 100kVp/70mAs. but there was no relation with position. Surface dose decreased by mean 59% and deep dose decreased by 63% at 100kVp/70mAs compared at 120kVp/100mAs in phantom study while dose is measured as 1.11mGy at 100kVp/70mAs with straighten up position for maximum exposed area which is reduced by 10% compared with a lateral position in the same condition. Conclusion It’s impossible for exposure dose to be less than a certain value in order to satisfy a proper condition, 100kVpn/70mAs, at which the image quality is not effected. In this study, it results that prone position makes fine image especially for diagnosing patients before surgery rather than supine position does. consequently, this study shows that prone position have decisive role for the accurate examination of breast cancer
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