評估接受底片式乳房攝影病患之平均乳腺劑量－－年齡之影響

A survey of average glandular dose to patients undergoing screen/film mammography-the influence of age

本研究的目的為探討台灣女性年齡改變時對乳房攝影中平均乳腺劑量的影響，本研究回溯分析4092張頭腳方向之底片式乳房攝影影像，受檢者的年齡層介於30-79歲之間，分析每次攝影的暴露參數以計算出病人的平均乳腺劑量。結果顯示，乳房壓迫厚度和射束品質隨年齡的改變僅有些微變化，年齡對於乳腺比例卻有很大的影響。本研究中的乳房壓迫厚度、乳腺比例和乳腺平均劑量的平均值分別為4.2cm，54%以及1.70mGy。在病人年齡層為55-59歲和75-79歲之乳腺平均劑量分別為30-34歲病人之0.96和0.70倍。總而言之，在女性年齡層介於30-59歲時，年齡在乳腺平均劑量上顯現出較小的影響；而當年齡差異增加，乳腺平均劑量之變動也隨著增大。

The aim of this study was to investigate age-related changes in average glandular dose (AGD) for Taiwanese women. A retrospective review of 4092 craniocaudal screen/film exposures was conducted. Subjects’ age range was 30-79 years. The radiographic factors of each exposure were analyzed to determine the patient AGD. The results show that age has a strong modifying effect on glandularity, while the compressed breast thickness (CBT) and beam quality needed varied only slightly with age. The average values of CBT, glandularity, and AGD were 4.2 cm, 54%, and 1.70 mGy, respectively. The values of patient AGD for the age bands 55-59 and 75-79 years were factors of 0.96 and 0.70, respectively, compared to the age band 30-34 years. In conclusion, age appears to have a small effect on AGD for women surveyed in the age interval 30-59 years. As age differences increase, variation in AGD increases.