中文摘要：

乳腺是对辐射致癌最敏感的组织之一,而辐射致癌风险与受照剂量密切相关。为更准确地评估电离辐射所致乳腺受照剂量,本文建立了一个具有皮肤、皮下脂肪、乳房后侧脂肪、悬吊韧带、纤维腺体区脂肪、输乳管、小叶、输乳窦和乳头等精细结构的乳房数学模型,并将其体素化为体素模型。考虑到在乳腺X射线摄影中的应用,对乳房体素模型进行头尾位（CC位）压迫,建立压迫乳房模型,并与中国成年女性参考人体素体模（CRAF）相拼接。采用Geant4对乳腺X射线摄影进行蒙特卡罗模拟,计算了一系列平均腺体剂量转换因子。根据计算结果,采用精细乳房模型计算的平均腺体剂量转换因子低于我国现行国家标准的取值,但与美国放射学会（ACR）标准的取值差别不大。

英文摘要：

The female breast is one of the most radiosensitive organs,and mean glandular tissue（MGD）is regarded as the most reasonable dose descriptor related to the risk of radiation-induced breast cancer.To estimate the MGD more precisely,a mathematical model with detailed structures of breast was constructed,which includes skin,subcutaneous fat layer,retromammary fat layer,Cooper＇s ligaments,intraglandular fats,ductal trees,lobules,lactiferous sinus,nipple and so on.The mathematical model was then voxelized to a voxel model.The voxel breast model was compressed in the craniocaudal direction for mammography.The compressed breast model was combined with the Chinese reference adult female voxel model（CRAF）,and Monte Carlo simulation ofmammography was performed based on it with Geant4.A series of glandular tissue dose conversion factors for mammography were calculated.The data calculated in this work are smaller than the data from specification for testing of quality control in mammography of China.However,the difference between the data calculated in this work and those from American College of Radiology（ACR）is small.