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

선량감소효과를 위한 저관전압 복부CT의 추적검사에의 적용

안수현(Su Hyeon Ahn),조인완(In Wan Cho),강성진(Seong Jin Kang),강래욱(Rae Wook Kang),유병헌(Byeong Heon Yoo),김승식(Seung Sik Kim) 대한CT영상기술학회 2006 대한CT영상기술학회지 Vol.8 No.1

Purpose To study the analyse radiation dose, CT number, contrast scale, image quality of the patient who needs periodic follow-up examination by applying abdominal CT using low tube voltage. Materials & Methods To evaluate the image quality of abdomen, radiation dose, CT number and contrast scale follows in change of tube voltage, subjects are divided into two groups. One group is the patients able to be applied in the clinical analysis and the other group vvere used phantom. Somatom Sensation 16(Siemens, Erlangen, Germany) was used. Twenty patient were selected at random in the group which was applied periodic follow-up examination by CT. In this clinical study, tube current was fixed in 150mA, tube voltage was adjusted according to appropriate value of each examinations and then we measured CTDI values. The measurement of CT number of each organs was performed by setting up a lcm diameter ROI at abdominal organs in the same height of first lumbar vertebra by using images of arterial phase. Quality of the abdominal images were graded into the 3 degrees by two radiologists in consensus. Abdominal shaped acrylic phantom was used in phantom study. Ion chamber was inserted into the holes located on the center and periphery of the phantom, and around there, then scaned, and radiation dose were automatically displayed by the reader which were 80kVp, 100kVp, 120kVp, 140kVp of tube voltage were applied to the phantom(diluted contrast medium with water 1:10 ratio), then the phantom was scanned and a 1cm diameter ROI in the center of the image was measured CT number. Results CTDI value was m decreased in 100kVp by 36%(11.70mGy vs 7.50mGy) in comparison with 120kVp. According to radiologist’ evaluation, there were 17 equivalent, 3 acceptable, 0 unacceptable in the group of 20 subjects. Radiation dose in the phantom study showed decreasing as tube voltage was lowered from 80kVp to 140kVp. Peripheral dose decreased by 38%, and central dose decreased by 41%. CT number showed 1365.9±4.4HU in 80kVp, 1046.1±3.7 in 100kVp, 862.8±3.2HU in 120kVp, 737.5±3.0 in 140kVp. Conclusion By applying the low tube voltage using abdominal CT to the patients who need periodical follow-up examination, the quality of the image is relatively high contrast scale without a lowering of image quality and we can decrease the effect of radiation dose.

Dual Energy를 이용한 Breast CT의 유용성 평가

이민수(Min Su Lee),김현주(Hyeon Ju Kim),김진배,김경준,주명식,오용운,조인완(In Wan Jo),변태권,유병헌(Byeong Heon Yoo) 대한CT영상기술학회 2014 대한CT영상기술학회지 Vol.16 No.2

목적 : Dual Energy CT로 Breast CT를 검사하여 GSI(gemstone spectral image) Scan을 통한 breast cancer의 영상학적 진단적인 가치를 높이고 유용성을 극대화 하고자 한다. 대상 및 방법 : 본 연구에 사용한 장비는 64-MDCT(Discovery 750HD, GE HEALTHCARE, Milwaukee, USA)를 이용하였으며 본원에서 Breast cancer 진단을 받은 20명의 환자를 임의로 선정하여 Dual Energy Breast CT로 GSI scan하였으며 팬텀연구를 바탕으로 임상연구를 시행 하여 정량적 정성적 분석을 이용하여 분석 평가하였다. 영상 데이터 분석은 Advantage workstation(Version 4.6, GE, USA)과 SPSS 18.0 for Windows: SPSS Chicago, IL)을 이용하였다. 결과 : Mammography용 ACR breast phantom을 이용하여 기존의 SECT와 실험에 적용한 DECT로 각각 물질의 HU값을 20회씩 측정하고 비교 분석한 결과의 경우 mass팬텀에서 SECT는 -15.79±0.78, DECT는 -14.02±1.27로 측정되었고, Nylon fiber팬텀은 SECT에서 3.2±0.4, DECT는 2.91±0.78로 측정되었으며, Specks팬텀의 경우 SECT에서 -23.39±0.25, DECT는 -34.59±2.83로 측정되었다. Ion camber용 아크릴팬텀을 이용하여 표면선량과 심부선량을 측정한 결과 표면선량 0시 방향의 경우 SECT에서 0.91±0.07, DECT에서 1.31±0.14, 3시방향의 경우 SECT에서 0.96±0.2, DECT에서 1.15±0.07, 6시 방향의 경우 SECT에서 0.86±0.05, DECT에서 1±0.02, 9시방향의 경우 SECT에서 0.7±0.14, DECT에서 1.14±0.08로 측정되었으며 중심부에서는 SECT에서 0.85±0.05 DECT에서 1±0.04로 측정되었다. GSI로 스캔하면 cancer의 용적(㎤)측정 및 입체적인(3D) 영상까지 재구성이 가능하여 진단적 유용성을 극대화 할 수 있었다. 또한 각 물질별 분석이 가능한 MD(Material Decomposition) 기능을 이용하여 cancer의 조영증강 패턴과 cancer의 성분분석이 가능하게 되었다. 정성적 분석 결과 DECT를 이용한 breast CT의 모든 영상에서 Equivalent 47, Acceptable 13, Unacceptable 0의 평가를 받았다. 결론 : Breast CT에서 DECT(Dual Energy Computed Tomography)는 GSI Scan을 통한 MD분석, Volume measurement, Color coding, Spectral HU curve 등을 적용한 영상의 재구성 분석방법으로 breast cancer의 다양한 진단방법을 제시할 수 있는 긍정적인 효과를 기대할 수 있었다. Purpose : We want to maximize the usability and value of a radiological diagnosis of breast cancer that examine the Breast CT with Dual Energy CT using the GSI scan. Material and Methods : Instrument used in this study was 64-MDCT(GE), doing the GSI scan with Dual Energy Breast CT that selected 20 patients randomly who underwent Breast cancer diagnosis in this hospital with Dual Energy Breast CT, the conducted clinical study and evaluation were analyzed using quantitative and qualitative analysis based on the phantom study. Analysis of radiological data is Advantage workstation(Version4.6) SPSS18.0 for Windows: SPSS Chicago, the IL). Results : As a result for HU value of each substance used for ACR breast phantom of Mammography measured 20 times with existing SECT and applied to experiment DECT, it is measured at -15.79±0.78 for SECT, -14.02±1.27 for DECT in mass phantom, 3.2±0.4 for SECT, 2.91±0.78 for DECT in Nylon fiber phantom, -23.39±0.25 for SECT, -34.59±2.83 for DECT in Specks phantom. As result of depth and surface dose using acrylic phantom of ion camber, it is 0.91±0.07 for SECT and 1.31±0.14 for DECT at 12’clock direction, 0.96±0.2 for SECT and 1.15±0.07 for DECT at 3’o clock, 0.86±0.05 for SECT and 1±0.02 for DECT at 6’o clock, 0.7± 0.14 for SECT and 1.14±0.08 for DECT at 9’o clock, 0.85±0.05 for SECT and 1±0.04 for DECT in center. As result of the size of the cancer compared with reports of histopathology Breast cancer and obtained image after DECT,it is measured similarly in all patients except for one and we could maximize diagnosis usability for reconstruction of three-dimensional (3D) images of the measurement volume(㎤) of cancer. As using analyzable MD(Material Decomposition) function of each substance, component analysis and contrast enhancement patterns of cancer has become possible. As a result of qualitative analysis, it is rated Equivalent 47, Acceptable 13, Unacceptable 0 from the all images of breast CT using DECT. Conclusion : DECT in Breast CT is the method of analysis that applied for MD Analysis, Volme measurement, Color coding, Spectral HU curve through GSI Scan, it is expected positive effect suggesting various diagnosis method.

저관전압 흉부 CT검사 시 CT value의 변화에 따른 영상평가

김현주(Hyun Joo Kim),송훈(Hoon Song),조인완(In Wan Cho),안수현(Su Hyeon Ahn),신훈(Hoon Shin),유병헌(Byeong Heon Yoo),김승식(Seung Sik Kim) 대한CT영상기술학회 2007 대한CT영상기술학회지 Vol.9 No.1

Purpose Experiments carried out on the patients who visited this department for pulmonary disease and need CT scans for Follow-up to observe change of CT value, evaluation of image quality and decrease of radiation dose as change of tube voltage Materials and Methods Subjects were the patients of 20 persons visited this department for pulmonary disease and Somatom Sensation 16(Siemens, Erlangen, Germany) was used. Measurement of CT value as change cf tube voltage was done by setting up ROI diameter of 1cm at the height of thyroid, aortic arch, right pulmonary artery in arterial phase image using 100OkVp, measuring 3 times, and recorded the average. CT value of phantom was measured by scanning phantoms which means contrast media diluted by normal saline by various ratio with tube voltage of 80kVp, 100kVp, 120kVp, 140kVp and recorded the average of 3 CT values of center of phantom image. In analysing radiation dose, CTDIvol. values of the latest arterial phase image of 120kVp and as this research set that of 100kVp were analyzed comparatively. 2 observers graded quality of chest images by 5 degrees (UnaccepTable, Suboptimal, Adequate, Good, Excellent diagnostic quality). Results CT value of chest image increased at 100kVp by 14.06%~27.26% in each ROI than 120kVp. CT value of phantom increased as tube voltage lowered at various concentration of contrast media. CTDIbol. decreased at 100kVp(5.00mGy) by 36% than 120kVp(7.80mGy) in radiation dose analysis. here were 0 UnaccepTable, 1 Suboptimal, 3 Adequate, 10 Good, 6 Excellent diagnostic quality in totally 20 persons. Conclusion Chest CT scanning with low kilo-voltage for patients who need CT scan repeatedly can bring images valuable for diagnose, and decrease radiation dose against patients.

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.

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.

고밀도 물질에 기인한 CT영상 화질저하 개선을 위한 Iterative MAR 알고리즘 적용의 유용성에 관한 연구

강지원(Ji Won Kang),조인완(In Hwan Jo),김현주(Hyeun Joo Kim),정우준(Woo Joon Jeong),고병근(Byeung Geun Go),이정탁(Jeong Tak Lee),유회성(Hoi Seong Yoo),유병헌(Byeong Heon Yoo) 대한CT영상기술학회 2016 대한CT영상기술학회지 Vol.18 No.2

Purpose: In this research we tried to know the limitation and how much IMAR algorithm useful is in the clinical field by the evaluation of image and ana lysis using image data from phatom research and clinical research which used the Iterative MAR(Metal Artifact Reduction) algorithm from Inc. C that chose the way to get the data through its own HU of the kinds of metal in the human body(Titanium:4.5g/cm³ Around 6500HU, Stainless steel:7.8g/cm³ Around 50000HU, Gold:19.3g/cm³ Over 100000HU). Materials and Methods : We made the phantom with the dense material used in the replacement arthroplasty(L-spine : Titanium, Hip joint : Stainless steel), made of platinum for aneurysm in cerebral vessels and gold for dental filling. Also we used these machines, Somatom Derinition Flash from Inc. 5 and 64-MDCT Discovery 750 HD from Inc. G. we had studied from 1st May to 31st Oct. in 2015 using the image data from the patients to visit the hospital for f/u test. We used Advantage workstation program for alnalysis. We chose the ROI sized 2mm at the same part of Black Streak artifact and White streak artifact to record the average of the CT value after measuring it 20 times. Calculating the attenuation number, using the CT value measured, we calculate the attenuation number for each machines as the percentage to know how much the attenuation decrease, then compared and analyzed that. We got the image data after scan and set the same WW/WL of image data through Advantage Workstation program for research about clinical image. After then two groups, one consists of 2 radiologists and another one consists of 3 radiology technicians, evaluate how much the artifact reduce and the factors deciding the image quality such as resoultion and contrast. Result : As a result of converting attenuation coefficient into a percentage in the phantom research, Black streak artifact and White streak artifact of GDC coil image with MAR algorithm were 94% and 51% but both of them of GDC coil image with IMAR algorithm were 1% and 37%. Both of them decreased by 93% and 14% each. In Titanium, Black streak artifact decreased by 6%, from 17% to 11% and White streak artifact decreased by 19%, from 21% to 2% after using IMAR algorithm instead of MAR. In stainless steel Black streak artifact decreased by 5%, from 7% to 2% and White streak artifact decreased by 27%, from 34% to 7%. According to this phantom research, GDC coil, titanitum, and stainless steel are evaluated ‘adequate’ which had 3points in most of categories. Gold is the only one evaluated ‘good’ which had 4points in most of categories. This is the result of using IMAR algorithm instead of WFBP in the clinical image research, after converting attenuation coefficient into a percentage. Black streak artifact decreased by 17%, from 24% to 7%, and White streak artifact decreased by 7%, from 9% to 2% in plantium(GDC coil). In gold for dental filling, Black streak artifact decreased by 23%, from 33% to 10%, and White streak artifact decreased by 25%, from 30% to 5%. Also in stainless steel, Black streak artifact decreased by 48%, from 52% to4%, and White streak artifact decreased by 45%, from 46% to 1%. According to the evlauation for clinical images, GDC coil, titanium, and Stainless got 4points which meant ‘good’ in most of categories. Gold evaluated ‘adequate’, 3points in most of categories. Condusion : IMAR algorithm is more useful to reduce metal artifact caused by dense material rather than MAR algorithm. Using IMAR algorithm can provide information of various kinds to tissue with less artifact around metal foreign body, so it will be much more helpful for accurate diagnois. 목적 : 본 연구에서 인체에 삽입된 금속의 물질별(Titanium :4.5g/cm³ Around 6500HU, Stainless steel:7.8g/cm³ Around 5000HU, Gold:19.3g/cm³ Over 100000HU)로 고유의 HU(Hounsfield Unit)값을 적용하여 Data를 얻는 방식인 S사의 Iterative MAR(Metal Artifact Reduction) 알고리즘을 팬텀 연구와 임상 연구를 시행하여 획득된 영상데이터를 이용하여 정량적 분석과 임상 영상평가를 통하여 IMAR 알고리즘 유용성과 더불어 제한점을 알아보고자 하였다. 대상 및 방법 : 임상에서 치료목적으로 사용하는 재료 중 정형 외과적 치환술 시 이용하는 고밀도(L-spine: Titanium), (Hip joint: Stainless steel)물질과 머리 혈관 동맥류의 시술을 위해 사용하는 Platinum성분의 고밀도 물질인 GDC coil, 치아 충전재로 사용하는 Gold(Dental filling)를 이용하여 자체 제작한 팬텀과 이를 토대로 적용한 임상연구의 순으로 진행하였다. 연구를 위해 이용한 장비는 S사의 Somatom Definition Flash와 G사의 64-MDCT Discovery 750 HD를 사용하였다. 임상연구는 2015년 5월 1일부터 10월31일까지 5개월간 추적검사를 위해 내원한 환자의 영상데이터를 이용하였다. 정량적 분석은 Advantage workstation 프로그램에서 Black streak artifact와 White streak artifact의 동일한 부위에 직경 2mm의 ROI를 그려 CT value값을 20회 씩 측정 후 평균 CT value값을 기록 하였다. 측정 CT value 값을 이용하여 감약계수로 환산 후 각 장비별 인공물 감소 정도를 백분율로 계산 후 비교 분석 하였다. 임상영상 연구는 스캔 후 획득한 영상 Data를 Advantage Workstation 프로그램을 이용하여 WW/WL을 동일하게 설정 한 후 영상의학과 전문의 2명, 방사선사 3명 등 총 5명의 관찰자가 5점 척도로 인공물의 감소 정도 및 영상의 화질 좌우인자인 해상도 및 대조도 등의 항목을 적용하여 평가하였다, 결과 : 팬텀연구에서 감약계수를 백분율로 환산한 결과 GDC Coil에서 Black streak artifact와 White streak artifact순으로 MAR는 94%, 51%, IMAR는 1%, 37%로 93%, 14% 감소되었다. Gold에서 MAR는 30%, 22%, IMAR는 24%, 16%로 둘 모두 6% 감소되었다. Titanium에서 MAR는 17%, 21%, IMAR는 11%, 2%로 6%, 19% 감소되었다. Stainless steel에서 MAR는 7%, 34%, IMAR는 2%, 7%로 5%, 27% 감소되었다. 팬텀 영상 평가는 GDC coil, Titanium, Stainless steel 모두 Adquate(3점)이 가장 많았고, Gold는 Good(4점)이 가장 많았다. 임상 영상 연구에서는 감쇠계수를 백분율로 환산한 결과 Platinum(GDC Coil)에서 WFBP는 24%, 9%, IMAR는 7%, 2%로 17%, 7% 감소되었다. Gold(Dental filing)는 WFBP 33%, 30%, IMAR 10%, 5%로 23%, 25% 감소되었다. Titanium은 WFBP 93%, 61%, IMAR 35%, 15%로 58%, 46% 감소되었다. Stainless steel은 WFBP 52%, 46%, IMAR 4%, 1%로 48%, 45% 감소되었다. 임상 영상 평가는 GDC Coil, Titanium, Stainless steel 모두 Good(4점), Gold는 Adquate(3점)이 가장 많았다. 결론 : 고밀도 물질에 의한 Metal Artifact를 기존의 MAR Algorithm 보다 IMAR Algorithm을 적용시켰을 때 보다 유용하게 감소시킬 수 있으며. IMAR는 Artifact가 감소된 금속구조물주변의 다양한 조직들의 정보를 제공할 수 있어 영상의학과 판독의와 임상의에게 정확한 진단을 결정하는데 많은 도움을 줄 수 있을 것으로 사료된다.