• The Journal of the Korea Contents Association
• /
• v.15 no.11
• /
• pp.322-328
• /
• 2015

This study evaluated the diagnostic value and compares the Mammogram Tomosynthesis, and as compared to the AGD, was studied with respect to utilization of Tomosynthesis. During January 2015 one month were enrolled patients admitted to 62 people present. The ACR phantom was used. AEC was set to be. kVp is fixed and given a step-by-step changing the mAs analyzed AGD. Tomosynthesis was superior to the distinction of breast lesions when compared with Mammogram showed a noticeable difference in contrast. AGD(Average Glandular Dose) was higher 0.33 mGy. However, in the long run, the dose was reduced. Tomosynthesis is therefore increase the diagnostic value of the breast, a examination that can reduce the dose.

• Journal of radiological science and technology
• /
• v.28 no.4
• /
• pp.293-299
• /
• 2005

In the present investigation, we analyzed the data of 1,318 patients (2,636 images) who underwent mammographic examinations and obtained the distribution of the patient age and compressed breast thickness. We measured also average glandular doses (AGD) as function of compressed breast thickness. In order to obtain the values of AGD, we measured half value layer (HVL) and tube output (mR/mAs) for each kVp and target/filter combination. Entrance surface air kerma (ESAK) was calculated from the tube output as measured for each voltage used under clinical conditions and from the tube loading (mAs). AGD per exposure were calculated by multiplying the ESAK values by the conversion factors tabulated by Dance. We obtained in this study the following conclusions. The mean value of compressed breast thickness for cranio-caudal (CC) view was 35.8mm and that for medio-lateral oblique (MLO) view was 43.3 mm. The mean value of AGD for CC view was 1.55 mGy and that for MLO view was 1.70 mGy. The AGD for MLO view was 0.15 mGy (10%) higher than that for CC view because the thickness for MLO view was on average 4.8 mm higher than that for CC view. The values of AGD increased with increasing compressed brest thickness. The increased AGD value was on average 0.34 mGy per 10 mm in the thickness ranges $10{\sim}80\;mm$, therefore differences between the AGD values of each thickness were relative large. Thus, it is considered to need limited doses for mammography with the upper end of exposure range at several different compressed brest thickness.

• Journal of the Korean Society of Radiology
• /
• v.9 no.7
• /
• pp.535-540
• /
• 2015

Collimator has important functions with control primary X-ray that decrease radiation exposure dose for patients and reduce scatter ray and make better quality of image. But there are no regulations for X-ray mammography device of collimator, so widely used device adopt rectangularly controlled collimator. Though digital X-ray mammography device expand supply recently, rectangularly controlled collimator of film/screen mode still used. After searching for real condition of beam field with digital mammography, we made a multi-leaf collimator which is able to adjust the beam field in accordance with size and shape of breast, and we measuring up the transitions of image quality, average glandular dose(AGD) and, Dose area product(DAP). There are no significant differences between rectangularly controlled collimator and multi-leaf collimator, and DAP value decreased by 50.72%. As conclusion, there needs to expand the use of multi-leaf collimator for optimum adoption of beam field in digital mammography, and also need to develop an automatic regulation of beam field for reduce of exposure dose to patients.

• Journal of radiological science and technology
• /
• v.39 no.4
• /
• pp.483-491
• /
• 2016

The conditions after exposure to digital mammography and digital breast tomosynthesis were analyzed. The examinations for the ACR phantom were done using manual exposure, not auto exposure, to examine image discrimination and patient dose. As a result, the following results were derived: In the CC exposure, the kVp was 2kVp higher while mAs decreased to 58.6% for the 3D tomography. Such result showed an approximate decrease of 60mAs. At that time, the patients' Average Glandular Dose (AGD) was 1.65mGy in 2D and 1.87mGy in 3D; thus, AGD of 3D was shown to have about 1.13times higher. The result of the manual exposure revealed a reduced mAs of up to 80%; there was no effect in the assessment standard in terms of image discrimination, resulting in more than 10 points. When mAs was reduced to 80% in the manual exposure for ACR phantom, AGD was decreased to 0.66mGy. The diagnostic values of images were maintained and patients dose was reduced in the manual exposure in the AEC condition for 3D. Since the use of 3D has recently increased, using the manual exposure has been recommended in this study to improve the diagnostic value, while, simultaneously reducing patients dose.

• Journal of the Korean Society of Radiology
• /
• v.6 no.2
• /
• pp.121-127
• /
• 2012

Of this study, it was found that there were 250 mammographic units in total installed and used in the areas for this study, and 36 units were used in general hospitals, 53 units in hospitals and 116 units in clinics. That is, the units in clinics accounted for 50% out of the whole units. As for the image acquisition method, it was found there were 131 units using F/S, 67 units using CR and 7 units using DR respectively. At present, F/S system was mainly used in the areas. As for the materials of target/filter, it was found that Mo/Mo was mostly used (66%), followed by Mo/Rh (25%). As for the size of focus, both 0.1 mm for small focus and 0.3 mm for large focus were mainly used for the units.

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

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

• Radiation Oncology Journal
• /
• v.28 no.3
• /
• pp.177-183
• /
• 2010

Purpose: Simulation using computed tomography (CT) is now widely available for radiation treatment planning for breast cancer. It is an important tool to help define the tumor target and normal tissue based on anatomical features of an individual patient. In Korea, most patients have small sized breasts and the purpose of this study was to review the margin of treatment field between conventional two-dimensional (2D) planning and CT based three-dimensional (3D) planning in patients with small breasts. Materials and Methods: Twenty-five consecutive patients with early breast cancer undergoing breast conservation therapy were selected. All patients underwent 3D CT based planning with a conventional breast tangential field design. In 2D planning, the treatment field margins were determined by palpation of the breast parenchyma (In general, the superior: base of the clavicle, medial: midline, lateral: mid - axillary line, and inferior margin: 2 m below the inframammary fold). In 3D planning, the clinical target volume (CTV) ought to comprise all glandular breast tissue, and the PTV was obtained by adding a 3D margin of 1 cm around the CTV except in the skin direction. The difference in the treatment field margin and equivalent field size between 2D and 3D planning were evaluated. The association between radiation field margins and factors such as body mass index, menopause status, and bra size was determined. Lung volume and heart volume were examined on the basis of the prescribed breast radiation dose and 3D dose distribution. Results: The margins of the treatment field were smaller in the 3D planning except for two patients. The superior margin was especially variable (average, 2.5 cm; range, -2.5 to 4.5 cm; SD, 1.85). The margin of these targets did not vary equally across BMI class, menopause status, or bra size. The average irradiated lung volume was significantly lower for 3D planning. The average irradiated heart volume did not decrease significantly. Conclusion: The use of 3D CT based planning reduced the radiation field in early breast cancer patients with small breasts in relation to conventional planning. Though a coherent definition of the breast is needed, CT-based planning generated the better plan in terms of reducing the irradiation volume of normal tissue. Moreover it was possible that 3D CT based planning showed better CTV coverage including postoperative change.