폐음 기반 폐섬유증 질병 진단에 관한 연구

이준협(Jun Hyub Lee),최재민(Jae Min Choi),김효수(Hyosu Kim) 한국통신학회 2024 한국통신학회 학술대회논문집 Vol.2024 No.1

저 선량 흉부 CT 검사 시 인공심장박동기에 의한 인공물 영향

이준협(Jun-Hyub Lee),강선영(Sun-young Kang) 대한CT영상기술학회 2020 대한CT영상기술학회지 Vol.22 No.1

인공심장박동기와 제세동기를 삽입한 경우에 발생하는 인공물이 폐암의 조기 발견을 위해 시행되는 저선량 흉부CT에서 어떠한 영향을 주는지 알아보고자 한다. Lungman phantom과 인공심장 박동기를 이용하여 대조군과 실험군을 설정하여 인공심장박동기 주변 인공물의 CT value와 표준편차를 측정하였다. 인공심장박동기 주변으로 영상정보를 상실 (black-hole artifact) 하거나 선속 경화(streak artifact) 인공물을 확인하였다. 수검자들의 다양한 체형과 인공심장 박동기의 위치에 따라 폐암의 조기발견을 위한 저 선량 흉부CT 검사 시 수검자들에게 미세 병변의 발견을 저해하는 요인으로 작용할 것이라 생각되며 임상에서의 실질적인 검사에 적용할 수 있는 더 많은 연구가 필요할 것이다. We would like to find out how the artificial insemination of an artificial cardiac pacemaker and defibrillator affects the low-dose chest CT performed for early detection of lung cancer. Using Lungman phantom and artificial heart pacemaker, the control and experimental group were set up to measure the CT value and standard deviation of the man-made objects around the artificial heart pacemaker. Black-hole artifact (black-hole artifact) or pre-speed curing (streak artifact) artifacts were identified around the artificial heartbeater. Depending on the various body types of the examinees and the location of the artificial heart pacemakers, low dose chest CT examinations for early detection of lung cancer are thought to serve as inhibitors to the detection of fine lesions and will require more research to be applied to practical examinations in clinical trials.

심부정맥혈전증 검사시 Tracker 기법의 유용성 평가

이윤상(Yun Sang Lee),이준협(Jun Hyub Lee),남진현(Jin Hyun Nam),박성수(Seong Soo Park),이경숙(Kyung Sook Lee),이장범(Jang Beom Lee),최태규(Tae Kyu Choi) 대한CT영상기술학회 2009 대한CT영상기술학회지 Vol.11 No.1

Purpose In deep vein thrombosis test, 180sec latency test, one of existing test methods, has less accuracy of diagnosis because the image of venous thrombosis may be shown differently according to the status of cardiac output, artery occlusion, etc. thus in the present study, an attempt was made to look into the clinical availability of the new test method of performing test at the peak of a time-threshold curve for popliteal veins by using tracker method of multi-detector computed tomography. Materials and methods A retrospective study was made for total 32 patients consisting of 16 patients who took the existing test and 16 patients who took the new test among patients who visited the hospital between May and July 2008 and took deep vein thrombosis test. Using tracker method of the new test method, threshold was set to be high for popliteal veins, and tracking was started 50 seconds after beginning angiography, and when the tracking time curve started to bend downward from the peak of the threshold, test was done together with injection of a cell line in order to reduce arteriography. After test, comparison on the images between existing test method and new one was made and they went through statistical analysis, and based on these, the availability of those images in deep vein thrombosis test was evaluated. Results For thrombosis parts of total 32 patients who took deep vein thrombosis diagnosis, in existing test group, they were mainly found in large blood vessels of the pelvis and abdomen by order of iliac veins, femoral veins, and popliteal veins, while in new test group, they were equally found in popliteal veins, iliac veins, and femoral veins. This result implies that the existing test method has limitations in identifying the extent of the proximal portion for venous thrombosis according to the patient’s cardiac output, artery occlusion, etc. On the other hand, it was pointed out that the new test method showed a highly contrast-enhanced image of arteries, but the quality of image of venous phase could be raised by injection of a cell line. As a result of analysis by statistics of independent sample t-test between existing test group and new test group, a significance level was shown to be(p<0.05)p=0.008, which indicates there was statistically significant difference. Conclusion In the new test method, significantly high incidence of thrombosis was found with development of multi detector computed tomography, thus the new test method is deemed as more useful method in terms of objectivity and accuracy of diagnosis, compared to the existing test method. It is concluded that more prospective studies are required to be made for establishment of protocol with many cases.

저 선량 흉부 CT검사에서 Isocenter 불일치 시 CAD의 유용성 연구

강선영(Seon-Young Kang),이준협(Jun-Hyub Lee),김형철(Hyeong-Cheol Kim),이윤상(Yun-Sang Lee) 대한CT영상기술학회 2017 대한CT영상기술학회지 Vol.19 No.2

목적 : 컴퓨터 보조진단 활용의 폐 영역에서 저 선량일 때 Gantry aperture의 isocenter와 피사체 중심이 불일치하는 상황에서의 결절 검출을 통해 CAD의 유용성을 알아보고자 하였다. 대상 및 방법 : LungMan phantom내에 직경 3, 5, 8, 10, 12 mm의 고형결절 5개는 좌 폐에, 5, 8, 8, 10, 12 mm의 간유리 결절 5개는 우폐에 위치시킨다. LungMan을 Gantry aperture의 isocenter와 일치시킨 실험과, X-축 또는 Y-축 방향으로 30, 60, 90 mm, 이동시켜 실험하고 isocenter 불일치에 따른 Lung의 CT Number와 noise를 측정하여, 신호대잡음비(signal to noise ratio 이하, SNR)의 변화를 비교, 평가하였다. LungMan을 이동시켰을 때의 영상을 CAD를 이용하여 nodule 감별평가를 하였다. LungMan phantom내에 직경 8 mm의 일정한 크기와 재질의 고형 결절 20개를 정해진 배열 없이 위치시킨 후 LungMan을 Gantry aperture의 isocenter와 일치시켜 실험한 영상과, X-축 또는 Y-축 방향으로 30, 60, 90 mm 이동시킨 영상을 CAD로 분석하여 다수 결절에 대한 재현성을 평가하였다. 결과 : 1. LungMan이 Gantry aperture의 isocenter에서 X-축 또는 Y-축으로 멀어짐에 따라 CT Number와 noise는 증가하였고, SNR은 감소하였다. 2. 고형결절은 직경 5, 8, 10, 12 mm, 간유리결절은 직경 10, 12 mm의 결절이 LungMan의 중심을 X-축 또는 Y-축으로 이동시킴에 관계없이 모두 동일한 개수로 감별되었다. 3. 직경 8 mm의 일정한 재질의 고형 결절 20개는 세 번의 실험군에서 LungMan의 중심을 X-축 또는 Y-축 으로 이동시킴에 관계없이 모두 검출하였다. 결론 : CAD 프로그램은 저 선량과 isocenter 불일치 시 화질 저하의 조건에서 8 mm 고형결절의 검출 재현성이 우수하였으므로 유용한 보조진단의 도구가 될 수 있다. Purpose : The purpose of this study is to evaluate the usefulness of CAD in detection of nodules in the case of gantry aperture isocenter and object center discrepancy at low dose in the lung area of Computer-Aided Diagnosis. Materials and Methods : Five solid nodules with diameters of 3, 5, 8, 10, and 12 mm were placed in the left lung and Five GGO nodules with diameters of 5, 8, 8, 10, and 12 mm were placed in the right lung without alignment. Lungman was inspected in agreement with the isocenter of the gantry aperture and the Lungman was moved 30, 60 and 90 mm in the X or Y direction. After that, estimated CT number, noise and SNR of the lung according to the position change. 20 solid nodules of uniform size and material 8 mm in diameter were placed in the Lungman phantom without alignment. Lungman was inspected in agreement with the isocenter of the gantry aperture and the Lungman was moved 30, 60 and 90 mm in the X or Y direction. After that, the reproducibility of multiple nodules was evaluated. Results : 1. As Lungman moved away from the isocenter of the Gantry aperture away from the X-axis or Y-axis, CT Number and noise increased, and SNR decreased 2. The solid nodules were identified as 5, 8, 10, and 12 mm in diameter, and the GGO nodules were all of the same number irrespective of whether the 10 and 12 mm diameter nodules moved the center of the LungMan to the X-axis or Y-axis. 3. 20 solid nodules of uniform size and material, 8 mm in diameter, were detected in all three experimental changes without a defined arrangement, regardless of whether the LungMan was moved to the X-axis or the Y-axis. Conclusions : The CAD program can be a helpful diagnostic tool because of its excellent reproducibility of detection of 8 mm solid nodule under pool image quality conditions of low dose and isocenter inconsistency.

AEC를 적용한 흉부 CT 검사 시 pitch에 따른 생식선 차폐위치의 적정성 평가에 관한 연구

홍석호(Seok Ho Hong),이준협(Jun Hyub Lee),강선영(Seon Young Kang),이용재(Yong Jae Lee) 대한CT영상기술학회 2014 대한CT영상기술학회지 Vol.16 No.2

목적 : 흉부 CT 검사 시 gonad 부위에 차폐를 해줌으로써 gonad부위에 받는 선량이 감소하는 효과가 있지만, 생식선 차폐체가 포함된 topogram에서 AEC를 적용시 overscanning length의 영향으로 오히려 전체적인 선량이 증가할 수 있으므로 pitch에 따른 검사범위와 차폐체간의 적절한 위치를 알아보고자 한다. 대상 및 방법 : CT장비는 128 slice CT(Somatom Definition flash, Siemens, Germany)와 Lung-Man phantom을 사용하였다. 차폐거리의 정확성을 위하여 X-ray용 Ruler(115cm)를 이용하였으며, Gonad 부위 차폐를 위해 blanket shield(A-9344-5, 0.5 mm Pb, Bar Ray, USA)를 사용하였다. 생식선 차폐체가 없는 topogram 검사 후 AEC를 적용하였을 때, 차폐체가 없을 경우, 차폐체가 검사범위에 포함된 경우, 차폐체가 검사범위에 불포함된 경우의 선량 차이가 있는지 비교하였다. 생식선 차폐체가 있는 topogram검사 후 AEC를 적용하여 검사범위 마지막 지점부터 다리 방향쪽으로 1cm씩 이동하여 pitch를 0.5, 0.75, 1, 1.25, 1.5로 변화시킴에 따른 각각의 CTDIvol, DLP값으로 선량 증감율을 알아보았다. 결과 : 생식선 차폐체가 없는 topogram검사 후 AEC를 적용하였을 때, 차폐체가 없을 경우, 차폐체가 검사범위에 포함된 경우, 차폐체가 검사범위에 불포함된 경우 선량 차이가 없음을 확인하였다. 생식선 차폐체가 있는 topogram검사 후 AEC를 적용하여 검사범위 마지막 지점부터 다리 방향쪽으로 1cm씩 이동하여 pitch를 0.5, 0.75, 1, 1.25, 1.5로 변화시킴에 따라 검사한 경우에는 pitch가 증가할수록 overscanning length 범위가 증가하므로 CTDIvol, DLP 역시 증가하는 것으로 나타났다. pitch 별로 검사범위와 생식선 차폐체간의 적절한 차폐거리가 필요한 것으로 나타났다. 결론 : AEC를 적용한 흉부 CT 검사 시 topogram내에 생식선 차폐체가 포함되어 검사하는 경우 overscanning length로 인한 선량 증가를 고려하여 pitch에 따른 검사범위와 생식선 차폐체간의 적절한 거리를 두고 차폐 할 것을 제안한다. Purpose : There is a dose reduction effect by gonad shield when scanning chest CT. But, dose can be increased by influence of overscanning length when applying AEC in topogram included in gonad shield. So, We investigated appropriate shield distance of gonad shield each pitch. Materials and methods : 128 slice CT equipment (Somatom Definition flash, Siemens, Germany) was used and experimental subject was Lung-Man phantom. For the accuracy of shield distance 115 cm X-ray Ruler was taken. Blanket shield(0.5 mm Pb, Bar Ray, USA) was used for gonad shield. When applying AEC in topogram not included in gonad shield, and if there is no shield and there is shield in scan range or outside, we compared to dose difference. AEC was applied in topogram included in gonad shield and we investigated dose rate of change in CTDIvol and DLP value by 0.5, 0.75, 1, 1.25 and 1.5 pitch scanned and 1 cm by moving in the direction of the foot from the last post of scan range. Results : We sustained that there was no change of dose when applying AEC in topogram not included in gonad shield, and if there is no shield and there is shield in scan range or outside. The more pitch was, the more overscanning length range was when applying AEC in topogram included in gonad shield and 0.5, 0.75, 1, 1.25, and 1.5 pitch scanned and 1cm by moving in the direction of foot from the last post of scan range. So, CTDIvol and DLP value also was increased. Appropriate shield distance of gonad shield was needed each pitch. Conclusions : Dose was increased by influence of overscanning length in topogram included in gonad shield in chest CT applied AEC. So, shielding of appropriate shield distance was proposed each pitch.

Develop of Maximum Endurance Time Curve for Thumb Pressure

이성용(Sung-Yong Lee),공용구(Yong-Ku Kong),최경희(Kyeong-Hee Choi),이준협(Jun-Hyub Lee) 대한인간공학회 2016 대한인간공학회 학술대회논문집 Vol.2016 No.11

Objective: The aim of this study is to develop the endurance time curve for thumb pressure of male subjects and compare to several literature. Background: Most of manual materials handling tasks are require to static constant force exertion or repetition. These are lead to musculoskeletal disorders. The relation between relative force and maximum endurance time is employed in a number of methods for ergonomics study. However, there is no study on the thumb muscle. Method: The present study compared the maximum endurance time of thumb according to the relative force for male. 10 healthy males were recruited as participants. The independent variable was relative target force value (10%, 20%, 40%, 60%, 80% and 100% maximum voluntary contraction of thumb). The dependent variables were maximum endurance time (min.). Results: The result show that endurance time increased with decease of relative target force level, especially 10%MVC (13.16 ± 9.17 min.). When comparing the thumb endurance curve which was developed in this study, thumb endurance time was shorter than other several literature (when <20%MVC). However, most showed a similar trend. Conclusion: The Endurance time discrepancy is caused by many factors (e.g. Muscle fiber, Muscle temperature, Muscle group). To clarify the major cause of discrepancy, therefore, further study need to consider of various subjects characteristic. Application: The results of this study can be used as the basis for the work design and pipette design.

64MD CT를 이용한 흉부외상 환자 VR 영상의 알고리즘별 분석

이윤상(Yun Sang Lee),이준협(Jun Hyub Lee),최소영(So Young Choi),박성수(Seong Soo Park),이경숙(Kyung Sook Lee),김기원(Gi Won Kim) 대한CT영상기술학회 2007 대한CT영상기술학회지 Vol.9 No.1

Purpose We tried to find out the utility comparing and analyzing the difference of image quality according to the algorithm(filter) change and the 3 dimension volume randering of breast CT pre-contrast enhancement and post-contrast enhancement images by 64 multi-detector among the breast injury patients who came into the emergency room of our hospital. Materials and Methods We analyzed the difference of the attention and the quality of the image is excellent in some algorithm while analyzing the image algorithm statistically that ga: the most excellent assessment of image algorithm and post contrast enhancement assessing 3D VR image that has changed the image filter from 1 point(the best) to 5 points(the worst) by the 3D specialized radiator and the image medicine specialized doctor that has changed the image filter targeting the patient which we implemented pre contrast enhancement and post contrast enhancement breast CT of the breast injury patient of 34 students who came into our hospital emergency room from August to November, 2006. Results For the image assessment according to each algorithm, YD filter got the most excellent assessment, and rather than the CT of post contrast enhancement, the YD filter of pre contrast enhancement got better assessment, but the attention P showed as 0.197 to be insignificant in the difference of image according to the change of algorithm of the image of the pre contrast enhancement CT and the image of post contrast enhancement. Conclusion If the differences in breast CT of pre contrast enhancement and post contrast enhancement are trivial, by providing information and breast 3D VR image in the quick and formalized way by one post contrast enhancement CT inspection that can reduce additional width to the patient, we think breast 3D VR image to be useful.

흉부 CT영상에서 인공심장박동기가 진단에 끼치는 영향

이단비(Dan-Bi Lee),이준협(Jun-Hyub Lee),강선영(Sun-Young Kang) 대한CT영상기술학회 2023 대한CT영상기술학회 학술대회자료집 Vol.2023 No.1

Target Force Level에 따른 악력의 주관적 평가 정확도

공용구,박동현,최경희,신재민,이주희,이준협,Kong, Yong-Ku,Park, Donghyun,Choi, Kyeong-Hee,Shin, Jae-Min,Lee, Juhee,Lee, Jun-Hyub 대한인간공학회 2017 大韓人間工學會誌 Vol.36 No.5

Objective: The purposes of this experiment are an analysis of accuracy between target force level and subjective rating for the Target Force Level and an analysis of the patterns of subjective rating depending on target force level when there is no feedback from males for analysis. Background: The study of perceived exertion about the static contraction is processed with using among the matching procedure method between contralateral limbs, Exertion vs. Borg CR-10 scale and Exertion vs. %MVC (Maximum Voluntary Contraction). However, when there is no feedback, there is lack of the study on whether the subject can distinguish the subjective rating of the force depending on the target force levels. Method: Total 30 males, healthy subjects are measured the maximum grip strength, MVC, and then, each subject is measured the subjective rating and the accuracy with the random target force level (10, 20, 30, 40, 50, 60, 70, 80, and 90% MVC). Results: In the MVC study, males exerted 256.87N (${\pm}51.33$). In the subjective rating of grip strength increased for each Target Force Level (9 levels), higher subjective rating evaluated (p<0.05). In accuracy examination between target force level and subjective rating of grip strength by each %MVC, 10, 30, 40, 50, 70, 90% target force levels showed accurate strength (p>0.05). However, at 20% target force level, the subjects evaluated less subjective rating of grip strength than the target force (Underestimation), and at 60% and 80% target force level, the subjects evaluated more subjective rating of grip strength than the target force (Overestimation) (p<0.05). Conclusion: In the experiment, the MVC showed 256.87N (${\pm}51.33$) for the male adults and as the subjective rating value increased for each Target Force Level (9 levels), higher subjective rating evaluated (p<0.05). Moreover, the results of the accuracy test between target forces and subjective rating of the subjects showed that most participants rated a fairly accurate assessment of subjective rating of grip strength for Target Force Level (9 levels), except for 20%, 60%, and 80%MVC. Application: This experimental result would be used for basic data for the subjective rating of grip strength pattern by the target force level when the voluntary muscle is contracted.

Dose Distribution and Image Quality in the Gantry Aperture for CT Examinations

조평곤(Pyong-Kon cho),김유현(You-Hyun Kim),최종학(Jong-Hak Choi),이기열(Ki-Yeol Lee),김형철(Hyung-Cheol Kim),김장섭(Jang-Seob Kim),신동철(Dong-Chul Shin),이성현(sung-Hyun Lee),이준협(Jun-Hyub Lee),신귀순(Gwi-Soon Shin) 대한방사선과학회(구 대한방사선기술학회) 2009 방사선기술과학 Vol.32 No.4

슬라이스 두께(slice thickness)와 선속시준(beam collimation, BC)의 변화에 따른 CT gantry aperture 내의 선량 분포와 영상의 질을 알아보고자 하였다. CT장치로는 64-slice MDCT 스캐너(Brilliance 64, Philips, Cleveland, USA)를 사용하였다. 피사체가 없는 경우(air scan)의 선량측정을 위해 CT용 전리함을 gantry aperture내의 회전중심점(isocenter)과 12시, 3시, 6시, 9시 방향에서 회전중심점으로부터 5 cm 간격으로, 30 cm까지 BC를 변화시키면서 각각 측정 하였다. 또한 5개의 구멍(팬텀의 중심과 12시, 3시, 6시, 9시 방향)으로 구성된 CT head and body close phantom을 gantry aperture 내에 위치시키고 각 지점에서 선량을 측정하였다. Gantry apertue 내 피사체의 위치변화에 대한 영상의 노이즈를 비교하기 위해서 AAPM CT용 팬텀의 물통을 회전중심점과 12시 방향으로 5 cm와 10 cm 이동시킨 후 BC를 변화시키면서 스캔한 후 팬텀의 중심과 12시, 3시, 6시, 9시 방향의 지점에서 노이즈를 측정하였다. 이 중에서 몇 군데의 위치는 영상 영역에서 벗어나서 측정할 수가 없었다. 이대 노이즈 측정을 위해서 영상재구성의 슬라이스 두께는 5mm로 하였다. 측정한 결과 다음과 같은 결론을 얻었다: 첫째, CTDIw는 회전중심점으로부터 멀어질수록, BC가 넓어질수록 감소하였다. 둘째, BC의 넓이가 비슷한 경우는 CTDIw는 거의 유사한 값을 보였다. 즉, CTDIw는 검출기 배열의 수나 화소의 크기 보다는 전체적인 BC의 넓이에 의존하고 있음을 알 수 있었다. 셋째, air scan과 phantom scan 경우 모두에서 CTDIw는 BC가 증가될수록 감소하였다. 그러나 air scan의 경우보다 head pahntom scan 시 약 30%, body phantom scan 시 약 52% 정도 CTDIw의 값이 감소하였다. 넷째, BC와 팬텀의 위치 변화에 따른 노이즈 값은 2X0.5mm의 BC을 제외하고는 head pahntom scan한 경우 3.9~5.9, body phantom scan한 경우 5.3~7.4로 나타나, BC와 팬텀의 위치변화에 따라서 큰 차이가 없었다. 따라서 피사체의 위치가 gantry aperture 내 SFOV(scan field of view)에 포함될 경우 회전중심점에 정확하게 위치시키지 않아도 영상의 질에는 많은 영향을 미치지 않는다는 것을 알 수 있었다. The purpose of this study was to determine the dose distribution and image quality according to slice thichness and BC(beam collimation) in the gantry aperture. CT scans were performed with a 64-slice MDCT(Brilliance 64, Philips, Cleveland, USA) scanner. To determine the dose distribution according to BC, a ionization chamber was palced at isocenter and 5, 10, 15, 20, 25 and 30 cm positions from the isocenter in the 12, 3, 6 and 9 o'clock directions. The dose distribution for phantom scan was also measured using 12, 3, 6 and 9 o'clock directions. The image noise measurement for different BCs was performed using an AAPM CT phantom. Water-filled block of the pahntom was moved by 5 cm or 10 cm to the 12 o'clock direction, and the image noise was measured at the center of the phantom, and the points of 12, 3, 6 and 9 o'clock direction respectively. Some points were placed beyond the scan field of view (SFOV), so that measurement was not possible at that points. The results are as follows: The CTDIw showed a larger decrese as the source goes farther from the iso-center or the BC became wider. The CTDIw depends on the BC width more than the number of the channel of a detector arry. The value of CTDIW decresed with increasing BC, but the value decreased 16.6~31.9% in the lead pahntom scan in air scan and 51.0~64.5% in the body phantom scan. The value of the noise was 3.9~5.9 in the head and 5.3~7.4 in the body except for BC 2X0.5 mm regardless of the degree of deviation from the iso-center. When a subject was located within the SPOV, the position did not significantly affect image quality even if the subject was out of the center.