• 한국의학물리학회지:의학물리
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• 제21권3호
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• pp.281-290
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• 2010

최근 디지털 단층영상합성법을 영상유도 방사선 치료에 활용하기 위한 연구가 활발히 시도되고 있다. 적은 수의 투사영상으로 삼차원 영상재구성이 가능하기 때문에 환자에 대한 피폭선량을 줄일 수 있으며, 환자의 움직임을 최소화할 수 있는 장점이 있기 때문이다. 그러나 단층영상의 화질이 스캔 각도(${\beta}_{scan}$) 및 사용한 투사영상의 수 등 촬영조건에 크게 의존하는 단점이 있다. 본 연구에서는 필터링 후 역투사법을 이용한 디지털 단층영상합성의 구현에 대해 자세히 논하였으며, 이에 대한 최적 촬영조건에 대해 살펴 보았다. 이를 위해 시스템 성능을 신호 대 잡음비, 잔상퍼짐함수, 연산횟수를 조합한 이득함수로 정의하였으며, 다양한 촬영조건에 대해 실험을 통해 각 지표를 구한 후 평가하였다. 평가 결과 및 분석으로부터 큰 단위 스캔 각도(${\Delta}{\beta}$)로 60도 이상의 넓은 범위에 걸쳐 스캔을 할수록 높은 화질의 단층영상을 얻을 수 있다는 결론을 얻었다. 대략적으로 시스템 성능이 $\sqrt{{\Delta}{\beta}}{\times}{\beta}^{2.5}_{scan}$에 비례하였다. 만약 각 평가지표에 명확한 가중치를 부여할 수 있다면 보다 엄밀하고 구체적인 촬영조건을 구할 수 있을 것이다.

• 대한영상의학회지
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• 제83권5호
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• pp.1090-1103
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• 2022

목적 본 연구는 미세석회화가 의심되는 유방에서 정위적 조직검사에 앞서서 시행하는 디지털 유방단층영상합성법(digital breast tomosynthesis with the two-dimensional synthesized mammogram; 이하 DBT with 2DSM)과 전면디지털유방촬영술(full-field digital mammography; 이하 FFDM)의 진단능을 비교 평가하고 영상의 진단적 명확도를 평가하기 위해서 시행하였다 대상과 방법 2015년 1월에서 2020년 1월까지 후향적 연구로서 189명의 환자 중 정위적 조직검사를 통한 조직병리검사상 미세석회화 병변이 확인된 환자를 중 DBT with 2DSM나 FFDM을 시행한 환자군에서 시행되었다. 두 명의 영상의학과 의사가 눈가림 상태로, Breast Imaging Reporting and Data System (BI-RADS) 분류에 따른 미세석회화의 평가 및 본 연구에서 별도로 1-5점 척도를 통해 정의한 진단적 명확도에 대한 평가를 시행하였다. 결과 전반적인 검사자간 일치도는 우수한 것으로 확인되었다. 맥네머 검정에서 악성가능성이 높은 미세석회화(4B, 4C, or 5)의 검출에 있어서는 두 진단방법 간에 통계적 유의성은 보이지 않았으나, 양성가능성이 높은 미세석회화(4A)의 진단에 있어서는 통계적 유의성을 보였다. DBT with 2DSM는 FFDM보다 더 높은 가시성을 보임이 확인되었고, 치밀유방에서도 FFDM보다 진단에 있어서 더 우수하였다. 결론 DBT with 2DSM는 FFDM과 비교하여 미세석회화 병변에 대해서 더 높은 전반적 진단적 정확도와 진단적 명확성을 제공하였다. DBT with 2DSM는 FFDM보다 양성 미세석회화 병변에서와 치밀유방에서 우수성을 보였다. 본 연구에서는 치밀 유방에서 미세석회화 병변에 대해서 정위적 생검을 시행할 때 유용한 진단 기구로서의 DBT with 2DSM의 역할을 확인할 수 있었다.

• Korean Journal of Radiology
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• 제20권1호
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• pp.58-68
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• 2019

Objective: To compare digital breast tomosynthesis (DBT) and conventional full-field digital mammography (FFDM) in the detectability of breast cancers in patients with dense breast tissue, and to determine the influencing factors in the detection of breast cancers using the two techniques. Materials and Methods: Three blinded radiologists independently graded cancer detectability of 300 breast cancers (288 women with dense breasts) on DBT and conventional FFDM images, retrospectively. Hormone status, histologic grade, T stage, and breast cancer subtype were recorded to identify factors affecting cancer detectability. The Wilcoxon signed-rank test was used to compare cancer detectability by DBT and conventional FFDM. Fisher's exact tests were used to determine differences in cancer characteristics between detectability groups. Kruskal-Wallis tests were used to determine whether the detectability score differed according to cancer characteristics. Results: Forty breast cancers (13.3%) were detectable only with DBT; 191 (63.7%) breast cancers were detected with both FFDM and DBT, and 69 (23%) were not detected with either. Cancer detectability scores were significantly higher for DBT than for conventional FFDM (median score, 6; range, 0-6; p < 0.001). The DBT-only cancer group had more invasive lobular-type breast cancers (22.5%) than the other two groups (i.e., cancer detected on both types of image [both-detected group], 5.2%; cancer not detected on either type of image [both-non-detected group], 7.3%), and less detectability of ductal carcinoma in situ (5% vs. 16.8% [both-detected group] vs. 27.5% [both-non-detected group]). Low-grade cancers were more often detected in the DBT-only group than in the both-detected group (22.5% vs. 10%, p = 0.026). Human epidermal growth factor receptor-2 (HER-2)-negative cancers were more often detected in the DBT-only group than in the both-detected group (92.3% vs. 70.5%, p = 0.004). Cancers surrounded by mostly glandular tissue were detected less often in the DBT only group than in the both-non-detected group (10% vs. 31.9%, p = 0.016). DBT cancer detectability scores were significantly associated with cancer type (p = 0.012), histologic grade (p = 0.013), T and N stage (p = 0.001, p = 0.024), proportion of glandular tissue surrounding lesions (p = 0.013), and lesion type (p < 0.001). Conclusion: Invasive lobular, low-grade, or HER-2-negative cancer is more detectable with DBT than with conventional FFDM in patients with dense breasts, but cancers surrounded by mostly glandular tissue might be missed with both techniques.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3037-3040
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• 2013

Introduction: Mammography is the most basic modality in breast cancer imaging. However, the overlap of breast tissue depicted on conventional two-dimensional mammography (2DMMG) may create significant obstacles to detecting abnormalities, especially in dense or heterogeneously dense breasts. In three-dimensional digital breast tomosynthesis (3DBT), tomographic images of the breast are reconstructed from multiple projections acquired at different angles. It has reported that this technology allows the generation of 3D data, therefore overcoming the limitations of conventional 2DMMG for Western women. We assessed the detectability of lesions by conventional 2DMMG and 3DBT in diagnosis of breast cancer for Japanese women. Methods: The subjects were 195 breasts of 99 patients (median age of 48 years, range 34~82 years) that had been pathologically diagnosed with breast cancer from December 20, 2010 through March 31, 2011. Both conventional 2DMMG and 3DBT imaging were performed for all patients. Detectability of lesions was assessed based on differences in category class. Results: Of the affected breasts, 77 (75.5%) had lesions assigned to the same categories by 2DMMG and 3DBT. For 24 (23.5%) lesions, the category increased in 3DBT indicating improvement in diagnostic performance compared to 2DMMG. 3DBT improved diagnostic sensitivity for patients with mass, focal asymmetric density (FAD), and architectural distortion. However, 3DBT was not statistically superior in diagnosis of the presence or absence of calcification. Conclusions: In this study, 3DBT was superior in diagnosing lesions in form of mass, FAD, and/or architectural distortion. 3DBT is a novel technique that may provide a breakthrough in solving the difficulties of diagnosis caused by parenchyma overlap for Japanese women.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.117-120
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• 1996

In this paper, a new approach to acquire the cross-sentional image for automatic solder joint inspection of double-sided PCB using X-ray source is presented. We designed the apparatus with fixed X-ray source to realize the cross-sectional image by tunning object and detector synchronously. The cross-sectional images are captured at several view angle of X-ray source, the geometric image distortions caused by view angle and the shape of image intensifier are compensated. The precision variation of cross-sectional image by the change of view angle was investigated. Also we acquired the cross-sectional image to the solder joint of double-sided PCB and reconstructed the shape of solder joint.

• 대한의용생체공학회:의공학회지
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• 제29권1호
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• pp.46-51
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• 2008

We describe a backprojection filtering method for limited angle tomography. In order to reduce blur artifacts originated from the out-of-planes and control high-frequency noise, we employed two band-limited window functions, and which were realized by Hann filters in this study. Based on the experimentally measured data, the performance of the developed method is demonstrated by comparing with the conventional shift-and-add and filtered backprojection methods. Application of the developed method to the dental imaging has a potential to be used for the preoperative evaluation of the jaw for dental implants with much reduced patient dose instead of the conventional dental computed tomography.

• 대한영상의학회지
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• 제83권6호
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• pp.1327-1341
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• 2022

목적 국내 디지털 유방 토모신테시스(digital breast tomosynthesis; 이하 DBT) 사용 현황 및 영상의학과 의사들의 DBT에 대한 인식 및 사용자 요구조건에 관해 알아보고자 하였다. 대상과 방법 2021년 3월 대한 유방영상의학회 회원들을 대상으로 DBT와 관련한 26개의 객관식 문항과 1개의 주관식 문항이 포함된 온라인 설문조사를 시행하였다. 설문 문항은 기본 정보, 유방촬영술 및 DBT에 대한 진료 현황, DBT 인식, 관련 연구 경험 및 관심도를 포함하였다. 결과는 로지스틱 회귀분석을 이용하여 분석하였다. 결과 총 257명의 회원 중 120명이 응답하여, 응답률은 46.7%였다. 응답자 중 67명(55.8%)이 현재 DBT를 사용하고 있는 것으로 나타났다. DBT의 전반적인 만족도는 5점 척도를 사용하여 평균 3.31점이었다. DBT 검사의 장점으로 가장 많이 응답한 것은 소환율 감소(55.8%), 병변의 명확도 향상(48.3%), 유방암 발견율 향상(45.8%)이었고, 단점으로 많이 응답한 것은 환자의 추가비용 부담46.7%), 불충분한 미세석회화 검출(43.3%), 불충분한 진단능 향상 효과(39.2%), 방사선량 증가(35.8%)였다. DBT가 더 널리 사용되지 못하는 원인으로는 영상의 저장 용량, 판독 시간 증가를 주요 요인으로 응답하였다. 결론 DBT 사용이 보다 보편화되기 위해서는 사용자 불편사항과 피드백을 반영한 향후 기술개발이 필요하겠다.

• 대한방사선기술학회지:방사선기술과학
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• 제45권2호
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• pp.117-125
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• 2022

Although stationary inverse-geometry digital tomosynthesis (s-IGDT) is able to reduce motion artifacts, image acquisition time and radiation dose, the image quality of the s-IGDT is degraded due to the truncations arisen in projections. Therefore, the effects of geometric and image acquisition conditions in the s-IGDT should be analyzed for improving the image quality and clinical applicability of the s-IGDT system. In this study, the s-IGDT images were obtained with the various X-ray source arrangement types and the various number of projections. The resolution and noise characteristics of the obtained s-IGDT images were evaluated, and the characteristics were compared with those of the conventional DT images. The s-IGDT system using linear X-ray source arrangement and 40 projections maximized the image characteristics of resolution and noise, and the corresponding system was superior to the conventional DT system in terms of image resolution. In conclusion, we expect that the s-IGDT system can be used for providing medical images in diagnosis.

• 대한의용생체공학회:의공학회지
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• 제38권3호
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• pp.116-122
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• 2017

Physical breast phantoms would be useful for the development of a dedicated breast computed tomography (BCT) system and its optimization. While the conventional breast phantoms are available in compressed forms, which are appropriate for the mammography and digital tomosynthesis, however, the BCT requires phantoms in uncompressed forms. Although simple cylindrical plastic phantoms can be used for the development of the BCT system, they will not replace the roles of uncompressed phantoms describing breast anatomies for a better study of the BCT. In this study, we have designed a numerical voxel breast phantom accounting for the random nature of breast anatomies and applied it to the 3D printer to fabricate the uncompressed anthropomorphic breast phantom. The numerical voxel phantom mainly consists of the external skin and internal anatomies, including the ductal networks, the glandular tissues, the Cooper's ligaments, and the adipose tissues. The voxel phantom is then converted into a surface data in the STL file format by using the marching cube algorithm. Using the STL file, we obtain the skin and the glandular tissue from the 3D printer, and then assemble them. The uncompressed breast phantom is completed by filling the remaining space with oil, which mimics the adipose tissues. Since the breast phantom developed in this study is completely software-generated, we can create readily anthropomorphic phantoms accounting for diverse human breast anatomies.