• Progress in Medical Physics
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• v.21 no.3
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• pp.239-245
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• 2010

The purpose of this study is to comprehensively compare and evaluate the characteristics of image quality for digital mammography systems which use a direct and indirect conversion detector. Three key metrics of image quality were evaluated for the direct and indirect conversion detector, the modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE), which describe the resolution, noise, and signal to noise performance, respectively. DQE was calculated by using a edge phantom for MTF determination according to IEC 62220-1-2 regulation. The contrast to noise ratio (CNR) was evaluated according to guidelines offered by the Korean Institute for Accreditation of Medical Image (KIAMI). As a result, the higher MTF and DQE was measured with direct conversion detector compared to indirect conversion detector all over spatial frequency. When the average glandular dose (AGD) was the same, direct conversion detector showed higher CNR value. The direct conversion detector which has higher DQE value all over spatial frequency would provide the potential benefits for both improved image quality and lower patient dose in digital mammography system.

• Progress in Medical Physics
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• v.23 no.4
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• pp.261-268
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• 2012

Breast cancer is the second leading cause of women cancer death in Korea. The key for reducing disease mortality is early detection. Although digital mammography (DM) has been credited as one of the major reasons for the early detection to decrease in breast cancer mortality observed in the last 20 years, DM is far from perfect for several limitations. Digital breast tomosynthesis (DBT) is expected to overcome some inherent limitations of conventional mammography caused by overlapping of normal tissue and pathological tissue during the standard 2D projections for the improved lesion margin visibility and early breast cancer detection. In this study, we compared a DM system and DBT system acquired with different thickness of breast phantom. We acquired breast phantom data with same average glandular dose (AGD) from 1 mGy to 4 mGy under same experimental condition. The contrast, micro-calcification measurement accuracy and observer study were conducted with breast phantom images. As a result, the higher accuracy of lesion detection with DBT system compared to DM system was demonstrated in this study. Furthermore, the pain of patients caused by severe compression can be reduced with DBT system. In conclusion, the results indicated that DBT system play an important role in breast cancer detection.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.221-228
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• 2015

Purpose: In digital mammography QC program was used for the purpose of reducing low-dose and high-definition images of the radiation dose. Materials and Methods: In digital mammography using a QC phantom according to the average glandular dose in the exposure method MLO view $0^{\circ}C$, $30^{\circ}C$, $45^{\circ}C$, $50^{\circ}C$, $55^{\circ}C$, $70^{\circ}C$, was measured at $90^{\circ}C$ intervals, an image with Hologic QC program to the SNR and CNR was measured to evaluate. Results: The average dose in the MLO view was wired to $90^{\circ}C$ when the maximum was 1.75 mGy, it decreased approximately 6% was measured at $45^{\circ}C$ 1.65 mGy. In addition, 1.67 mGy, manual record, there were an average wired in accordance with the exposure dose and the dose of 1.52 mGy difference in the way auto filter. Image quality evaluation at every angular section SNR 50 ~ 52, shows a slight difference in CNR 11 ~ 12, it was included in the manufacturer's recommended value. Conclusion: The dose was lowest in MLO view $45^{\circ}C$, the difference between SNR and CNR were insignificant. The method of exposure will need a way to reduce the exposure of the patient's body or unnecessary patient by placing a difference in settings in which the characteristics.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.247-254
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• 2014

For the purpose of early diagnosis of the breast cancer, the attention on the screening mammography has been increasing-with supply of digital mammography day by day. Image quality is decided by target materials and filter combinations. Optimized selection by a glandular density and a thickness is needed, because these combinations change x-ray spectrum and effect to image quality. The purpose of this study is to find out optimized target and filter combinations through the evaluation of quantitative image quality and to suggest means which minimize patient dose through MCNPX. In results, spatial frequency resolution evaluation which is quantitative image quality evaluation method, MTF, NPS, DQE shows that we have to select Mo/Mo combinations or Mo/Rh combinations when compressed breast is thin. but in case of that when compressed breast is thick, we have to select Rh/Rh combinations or W /Rh combinations. In a comprehensive evaluation, W!Rh combinations which are not used in thin breasts in practice was superior to all image quality evaluation. This result is somewhat different-with clinical examination results. Secondary end point was organ dose evaluation, radiation dose of opposite breast was approximately 47 ~73% effectiveness when selecting standard breast. In conculsion, the most important point is that we have to select the optimal combinations-with considering dose evaluation and various thickness.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.4109-4114
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• 2015

Background: Full-field digital mammography (FFDM) with dense breasts has a high rate of missed diagnosis, and digital breast tomosynthesis (DBT) could reduce organization overlapping and provide more reliable images for BI-RADS classification. This study aims to explore application of COMBO (FFDM+DBT) for effect and significance of BI-RADS classification of breast cancer. Materials and Methods: In this study, we selected 832 patients who had been treated from May 2013 to November 2013. Classify FFDM and COMBO examination according to BI-RADS separately and compare the differences for glands in the image of the same patient in judgment, mass characteristics display and indirect signs. Employ Paired Wilcoxon rank sum test was used in 79 breast cancer patients to find differences between two examine methods. Results: The results indicated that COMBO pattern is able to observe more details in distribution of glands when estimating content. Paired Wilcoxon rank sum test showed that overall classification level of COMBO is higher significantly compared to FFDM to BI-RADS diagnosis and classification of breast (P<0.05). The area under FFDM ROC curve is 0.805, while that is 0.941 in COMBO pattern. COMBO shows relation of mass with the surrounding tissues, the calcification in the mass, and multiple foci clearly in breast cancer tissues. The optimal sensitivity of cut-off value in COMBO pattern is 82.9%, which is higher than that in FFDM (60%). They share the same specificity which is both 93.2%. Conclusions: Digital Breast Tomosynthesis (DBT) could be used for the BI-RADS classification in breast cancer in clinical.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.339-344
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• 2014

The quality control items of mammography devices in South Korea do not include the linearity, which is required by international standards. The linearity is a requirement for the adjustment of radiation dose and radiation quality. This study tested the linearity, which was suitable for the IEC 60601-2-45 standard, of the 5 mammography devices. All showed adequate results. Consistent measurement management is required for more developed quality control in the future.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.420.2-420
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• 2002

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.151-152
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• 2015

유방 검사에서 Tomosynthesis는 Mammogram과 비교하여 유방 병변 구별에 우수하고 확연한 대조도 차이를 보이며 추가적인 유방촬영 검사나 재촬영을 감소시킴으로서 장기적으로 환자의 피폭선량이 감소하는 효과를 보이므로 유방 병변 진단의 효과를 높일 수 있는 유용한 검사이다.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.162-168
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• 2007

For the past decade, the full-field digital mammography has been widely used for early diagnosis of breast cancer, and computer aided diagnosis has been developed to assist physicians as a second opinion. In this study, we try to predict the breast cancer using both mediolateral oblique(MLO) view and craniocaudal(CC) view together. A skilled radiologist selected 35 pairs of ROIs from both MLO view and CC view of digital mammogram. We extracted textural features using Spatial Grey Level Dependence matrix from each mammogram and evaluated the generalization performance of the classifier using Support Vector Machine. We compared the multi-view based classifier to single-view based classifier that is built from each mammogram view. The results represent that the multi-view based computer aided diagnosis in digital mammogram could improve the diagnostic performance and have good possibility for clinical use to assist physicians as a second opinion.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.05
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• pp.142-145
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• 1995

스크린-필름 X선 유방조영술(Screen-film X-ray mammography)은 유방암 진단을 위한 기준이 되는 방법으로 독보적인 위치를 차지하고 있다. 그러나 현재 사용되는 스크린-필름 방식 유방조영술은 여러 가지 한계점들이 인식되어 왔으며, 만약 유방 X선 사진(mammogram)이 디지탈 형식으로 곧 바로 얻어진다면 영상의 질(image quality)과 방사선량의 감소 가능성 관점에서 향상될 수 있다는 증거가 있다. 본 논문에서는, 디지탈 유방조영술에 대한 논리적 근거가 제시되고, 스크린 대용으로 개발되고 있는 X-선 검출기들과 이들을 사용한 여러가지 디지탈 유방조영술 시스템들을 분석 전망한다. 디지털 유방조영술을 실용화하기 위해 해결되어야 할 문제점들이 논의된다.