• 대한방사선기술학회지:방사선기술과학
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• 제30권1호
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• pp.13-23
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• 2007

유방촬영장치가 screen-film system에서 최근에는 빠른 속도로 digital system으로 교체되고 있는 추세이다. Digital system이 screen-film system에 비해 여러 가지 장점을 가지고 있다. 그 중의 하나가 digital detector가 screen-film보다 X선 흡수효율이 더 높으며, digital system 중에서도 direct digital detector가 indirect digital detector보다 흡수효율이 높다. 이에 입각하면 촬영 시 적은 선량을 주어도 되기 때문에 환자피폭선량이 감소한다. 그러나 임상 방사선사들이 느끼는 바는 달랐다. 따라서 이번 연구에서는 screen-film mammography system, computed mammography system, indirect digital mammography system, direct digital mammography system에서 glandularity가 30%, 50% 및 70%인 세 종류의 유방조직 등가팬텀을 이용하여 평균유선선량(AGD)을 측정하여 다음과 같은 결론을 얻었다. Screen-film보다 digital detector가 X선 흡수효율이 높지만, glandularity가 30%인 경우의 AGD는 오히려 SFM에서 가장 낮았고, 그다음 CM, IDM, DDM 순으로 증가되었다. 자동노출장치로 설정하였지만 두께나 glandularity에 따라 target/filter의 조합이 바뀌지 않고 Mo/Mo으로 계속 사용된 SFM에서는 AGD가 급격히 증가되었다. 따라서 높은 glandularity를 가진 두꺼운 팬텀을 위한 고에너지 촬영에서는 SFM에서 AGD값이 가장 높았고, 저에너지 촬영에서는 DDM에서 AGD값이 가장 높았다. 그러나 target/filter의 조합이 다양하게 바뀐 CM에서는 두께나 glandularity에 따른 AGD의 곡선이 가장 완만하게 증가하였으며, AGD값이 가장 낮았다. 이와 같이 두께와 glandularity가 증가함에 따라 target/filter의 조합이 Mo/Mo에서 Mo/Rh으로 더 증가하면 Rh/Rh으로 바뀌는 것이 AGD의 증가량이 적어 환자의 피폭선량 측면에서 바람직하다. 따라서 유방촬영에서 환자의 피폭선량을 평가하기 위해서는 검출효율 외에도 여러 가지 촬영 변수가 중요한 역할을 한다.

• 대한디지털의료영상학회논문지
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• 제16권2호
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• pp.25-29
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• 2014

The full-field digital mammography (FFDM), which has been known as a digital breast imaging system, carries out more outstanding performance than the screen-film mammography in overall image quality, skin & nipple, description of pectoral muscle and expression of micro-calcification. Thus, in this thesis, I perform experiments for both the enhancement of image quality and accurate estimation of the result in question, when detecting the very tiny-sized lesions in mammography. The image of digital breast X-rays is the important diagnostic tool for detecting early breast cancer and micro calcification lesion. The experiment of how much compression rate has an effect on the result of diagnosis in the case of microcalcification lesion, with JPEG2000 40:1 compression and over 50% enlargement led to obscure or definitely unacceptable diagnostic results is performed. And in another study of assessment of PSNR degree. I recognized the importance of standardized management system in mammography, where not to mention the accurate reading of the image has the most crucial role in diagnosis

• 한국산학기술학회논문지
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• 제12권10호
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• pp.4578-4589
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• 2011

최근 디지털 유방촬영술 분야에서 영상의 획득장치, 표시장치, 저장장치는 각각 별도의 분야로 발전하고 있다. 영상획득장치는 유방을 통과한 X-선을 흡수 포착하여 영상으로 저장하는 장치인데, 이를 이용하여 촬영된 영상은 여러 가지의 영상처리기술을 이용하여 진단이 가능하기 때문에 조기에 병변을 발견할 수 있다. 본 논문에서는 지금까지의 디지털 유방촬영술의 기술에 대하여 알아보고 구현된 디지털 유방X-선촬영기의 성능을 분석한다.

• 대한디지털의료영상학회논문지
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• 제12권2호
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• pp.133-138
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• 2010

The purpose of this study was to survey and test quality control of mammography system. The conclusion of this study is as follows ; First, The rate of pass for phantom image test shows that Film-Screen mammography system(F/S) and computed mammography system(CR) is 80%, Indirect digital mammography system(DR) is 100%. Second, The test of exposure dose shows that F/S is 921 mR. CR is 1,140 mR, DR is 474 mR. The grade of this testament is CR > F/S > DR. Third, The test of average glandular dose shows that F/S is 1,336 mGy, CR is 1,635 mGy, DR is 1,26 mGy. The grade of this testament is CR > F/S > DR. Fourth, The testament of resolution shows as follows F/S is 11~13 Lp/mm, CR is 4~5 Lp/mm, and DR is 5~7 Lp/mm(F/S > DR > CR) Fifth, The survey of projection, cassette, development and reading shows that user are indifference.

• 한국방사선학회논문지
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• 제15권2호
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• pp.147-152
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• 2021

본 연구에서는 선별적 유방촬영술 방법의 하나인 디지털 유방촬영술을 시행한 5320명의 유방암검진 결과를 후향적으로 분석하여 디지털 유방촬영술을 통한 유방암검진의 효용성을 살펴보았다. 유방암 검진을 시행한 환자들의 평균 나이는 57.7세(범위 30~87세)이며 암 발견율은 26건으로 1000명당 4.6건에서 유방암이 발견 되었다. 유방암 검진을 실시한 환자들의 위험인자별 암 발견율을 살펴보면 대부분 아무런 기저질환이나 기왕력이 없는 환자에서 유방암이 발견되는 비율이 높았다. 추가적인 초음파 검사등을 통해 확인된 위음성율은 3.6 %로 Film-Screen system의 위음성율에 비해 상대적으로 매우 낮은 것을 확인할 수 있다.

• 대한의용생체공학회:의공학회지
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• 제17권2호
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• pp.165-172
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• 1996

A scanning slot digital mammography system Luing a plastic scintillating fiber screen (SFS) is currently being developed To improve the x-ray interaction efficiency and absorption efficiency of an SFS, high Z elements can be added into the scintillating fiber core. In this paper, we investigated theoretically the zero spatial frequency detective quantum efficiency, DQE(0), and modulation transfer function, MTF(f), of three 2 cm thick SFSs made of polystyrene, polystyrene loaded with 5% by weight of lead, and polystyrene Loaded with 10% by weight of tin scintillating fibers. X-ray interaction efficiency, scintillating light intensity distributions and line spread functions were generated using Monte Carlo simulation. DQE(0) and MTF(f) were computed for x-ray energies ranging from 15 to 50 keV. Loading high Z elements into the SFS markedly increased the DQE(0). For x-ray energies used for mammovaphy, DQE(0) values of both high Z element loaded SFSs are about a factor of three higher than the DQE(0) of an Min-R screen. At mammographic x-ray energies, MTF(f) values of all three SFSs are Venter than 50% at 25 Ip/mm spatial frequency, and were found to be dominated by the 20 um individual scintillating fiber diameter used The results show that both hiP DQE(0) and spatial resolution can be achieved with the high Z element loaded SFSs, which make these SFSs attractive for use in a scanning slot detector for digital mammography.

• 대한디지털의료영상학회논문지
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• 제15권2호
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• pp.19-23
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• 2013

Purpose : Automatic exposure system(AOP mode) in DR Mammography of the STD and DOSE apply to women of childbearing age, the average glandular dose(AGD) and image quality by comparing was to demonstrate the usefulness of DOSE. Materials and Methods : Of the under 40 age 108 patients who visit to our hospital and examined STD and DOSE mammography from January 2008 to July 2013. AGD was obtained by DICOM header information provided by GE Senographe DS. STD and DOSE images were evaluated with obtained patients, Image J program was compared by calculating the SNR. Results : The average AGD of DOSE mode was 0.99mGy, and which decreased by 19% comparing to that of STD mode which was 1.18mGy. The two the average AGDs indicated statistically significant difference(p< .01). The average SNR of STD was 40.26, DOSE displayed, and to 39.68 in, there was no statistical significance. Results : The average AGD using DOSE mode which is one of DR mammography AOP modes decreased by comparing to that of STD mode showing no difference in image quality. The use of DOSE is considered to be useful.

• Korean Journal of Radiology
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• 제25권4호
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• pp.343-350
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• 2024

Objective: Artificial intelligence-based computer-aided diagnosis (AI-CAD) is increasingly used in mammography. While the continuous scores of AI-CAD have been related to malignancy risk, the understanding of how to interpret and apply these scores remains limited. We investigated the positive predictive values (PPVs) of the abnormality scores generated by a deep learning-based commercial AI-CAD system and analyzed them in relation to clinical and radiological findings. Materials and Methods: From March 2020 to May 2022, 656 breasts from 599 women (mean age 52.6 ± 11.5 years, including 0.6% [4/599] high-risk women) who underwent mammography and received positive AI-CAD results (Lunit Insight MMG, abnormality score ≥ 10) were retrospectively included in this study. Univariable and multivariable analyses were performed to evaluate the associations between the AI-CAD abnormality scores and clinical and radiological factors. The breasts were subdivided according to the abnormality scores into groups 1 (10-49), 2 (50-69), 3 (70-89), and 4 (90-100) using the optimal binning method. The PPVs were calculated for all breasts and subgroups. Results: Diagnostic indications and positive imaging findings by radiologists were associated with higher abnormality scores in the multivariable regression analysis. The overall PPV of AI-CAD was 32.5% (213/656) for all breasts, including 213 breast cancers, 129 breasts with benign biopsy results, and 314 breasts with benign outcomes in the follow-up or diagnostic studies. In the screening mammography subgroup, the PPVs were 18.6% (58/312) overall and 5.1% (12/235), 29.0% (9/31), 57.9% (11/19), and 96.3% (26/27) for score groups 1, 2, 3, and 4, respectively. The PPVs were significantly higher in women with diagnostic indications (45.1% [155/344]), palpability (51.9% [149/287]), fatty breasts (61.2% [60/98]), and certain imaging findings (masses with or without calcifications and distortion). Conclusion: PPV increased with increasing AI-CAD abnormality scores. The PPVs of AI-CAD satisfied the acceptable PPV range according to Breast Imaging-Reporting and Data System for screening mammography and were higher for diagnostic mammography.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3521-3526
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• 2016

Digital breast tomosynthesis (DBT) as a breast cancer screening modality, through generation of three-dimensional images during standard mammographic compression, can reduce interference from breast tissue overlap, increasing conspicuity of invasive cancers while concomitantly reducing false-positive results. We here conducted a systematic review on previous studies to synthesize the evidence of DBT efficacy, eventually 18 articles being included in the analysis. The most commonly emerging topics were advantages of DBT screening tool in terms of recall rates, cancer detection rates and cost-effectiveness, preventing unnecessary burdens on women and the healthcare system. Further research is needed to evaluate the potential impact of DBT on longer-term outcomes, such as interval cancer rates and mortality, to better understand the broader clinical and economic implications of its adoption.

• 한국방사선학회논문지
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• 제10권3호
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• pp.215-222
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• 2016

엑스선유방촬영술은 다양한 유방질환 중 석회화 병변을 진단하는데 가장 효과적인 방법이다. 환자의 의료피폭 저감과 진단에 필요한 최적의 영상을 얻기 위해서는 성능유지를 지속적으로 관리해야 한다. 엑스선유방촬영술에서 엑스선을 발생시키는 양극의 경사각도는 중심선을 기준으로 하기 때문에 조사야 내의 위치에 따라 엑스선관의 유효초점이 미세하게 달라질 수 있어 공간분해능의 차이가 발생할 수 있다. 본 연구에서는 디지털 엑스선유방촬영장치에서 검출기 위치에 따른 LSF를 측정하여 MTF를 계산함으로써 공간분해능 변화에 대해서 연구하였다. 와이어 직경에 대한 변화에서 $50{\mu}m$ 직경의 와이어의 경우 가장 높은 공간주파수 값을 나타냈으며 검출기의 픽셀보다 작은 직경을 갖는 와이어를 사용해야 검출기의 공간주파수에 따른 응답을 바르게 구할 수 있다는 것을 알 수 있었다. 조사야 내의 검출기의 위치에 따라서 공간주파수는 중심부분의 와이어가 나머지 와이어보다 우수한 MTF 특성을 보였으나, 그 차이는 미소하게 나타났다. 또한 중앙부분에서 반치폭 또는 유효초첨이 가장 작게 나타났으며 중앙에서 벗어날수록 반치폭이 증가하여 공간분해능이 낮아진 것으로 나타났다.