乳房攝影的模式化乳房與等效假體之發展與應用

Mammography is one of the important examinations used for the detection of breast cancer. The assessment of average glandular dose (AGD) and image quality are helpful for determining dose reduction strategies, and for developing new imaging techniques in mammography. To achieve these purposes, model breasts (mathematical phantoms) and breast phantoms are commonly applied in mammography. At present, the subjects used for the development of model breasts and breast phantoms are Western women. Few attempts have been made to investigate such information for Asian women. In view of the fact that the breast size of Taiwanese women is in general smaller than that of Western women, we explored four important topics in the present study. First was the development of an adjustable model breast for AGD assessment. The second was to develop equivalent breast phantoms for Taiwanese women. Third was to investigate breast dosimetry and age-related changes in AGD for Taiwanese women. The fourth was the development of an imaging-planning program of screen/film (SF) and computed radiography (CR) mammography for short chest-wall-to-nipple-distance (CWND) breasts. A retrospective review of 4226 SF mammograms (craniocaudal views) was conducted in this study. Breast parameters, including compressed breast thickness (CBT), CWND, compressed breast width (CBW), and glandularity were measured. The equivalent thickness of a polymethylmethacrylate (PMMA) phantom was determined for each breast using the exposure factors. The AGD for each exposure was estimated. The equivalence of PMMA phantoms and breasts obtained above was applied to develop the imaging-planning program for short CWND breasts. Results from the present study show that the average values of CBT, CWND, CBW, and glandularity of the women studied are 4.1 cm, 6.9 cm, 16.9 cm, and 54%, respectively. The average equivalent PMMA thickness is 4.0 cm, which is thinner than that reported in previous studies (4.5 cm). The mean AGD for Taiwanese women surveyed is 1.72 mGy, which is lower than those obtained for Western women in previous studies. The dose reduction is 4% between the age bands of 30-34 and 55-59 years, and 14% between the age bands of 30-34 and 65-69 years. By application of the imaging-planning program developed, adequately imaging parameters for short CWND breasts can be determined. In conclusion, an adjustable model breast and the equivalent breasts of 2.5-6 cm PMMA phantoms were developed for the age groups 30-49 years and 50-69 years. In this study, the AGD to patients increased with increasing CBT. As the difference in age increases, the variation in AGD increased. With application of the imaging-planning program in mammography, the variation in image quality of short CWND breasts can be minimized.

關鍵字

乳房攝影；假體；劑量

參考文獻

Bakic P R, Albert M, Brzakovic D and Maidment A D 2002a Mammogram synthesis using a 3D simulation. I. Breast tissue model and image acquisition simulation Med. Phys. 29 2131-2139

Bakic P R, Albert M, Brzakovic D and Maidment A D 2002b Mammogram synthesis using a 3D simulation. II. Evaluation of synthetic mammogram texture Med. Phys. 29 2140-2151

Beckett J R and Kotre C J 2000 Dosimetric implications of age related glandular changes in screening mammography Phys. Med. Biol. 45 801-813

Bliznakova K, Bliznakov Z, Bravou V, Kolitsi Z and Pallikarakis N 2003 A three-dimensional breast software phantom for mammography simulation Phys. Med. Biol. 48 3699-3719

Bloomquist A K, Yaffe M J, Pisano E D, Hendrick R E, Mawdsley G E, Bright S, Shen S Z, Mahesh M, Nickoloff E L, Fleischman R C, Williams M B, Maidment A D, Beideck D J, Och J and Seibert J A 2006 Quality control for digital mammography in the ACRIN DMIST trial: part I Med. Phys. 33 719-736

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乳房攝影的模式化乳房與等效假體之發展與應用

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