Inspeção Geral da Agricultura, do Mar, do Ambiente, e do Ordenamento do Territorio (IGAMOT), Seção Radiações Ionizantes, Rua de O Seculo, N.51, 1200-433, Lisbon, Portugal.
Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Estrada Nacional 10, km 139,7, 2695-066, Bobadela LRS, Portugal.
Radiography (Lond). 2022 May;28(2):333-339. doi: 10.1016/j.radi.2021.09.002. Epub 2021 Sep 24.
Digital Mammography (DM-2D) and more recently Digital Breast Tomosynthesis (DBT), are two of the most effective imaging modalities for breast cancer detection, often used in screening programmes. It may happen that exams using these two imaging modalities are inadvertently performed to pregnant women. The objective of this study is to assess the dose in the uterus due to DM-2D and DBT exams, according to two main irradiation scenarios: in the 1st scenario the exposure parameters were pre-selected directly by the imaging system, while in the 2nd scenario, the maximum exposure parameters were chosen.
The mammography equipment used was a Siemens Mammomat Inspiration. A physical anthropomorphic phantom, PMMA plates (simulating a breast thickness of 6 cm) and thermoluminescent dosimeters (TLDs) were used to measure entrance air kerma values on the phantom's breast and abdomen in order to successively estimate the mean glandular dose (MGD) and the dose in the uterus. For the two irradiation scenarios chosen, two-breast imaging modalities were selected: 1) DBT in Cranio-Caudal (CC) view (with 28 kV and 160 mAs as exposure parameters), 2) DBT and DM in Medio Lateral-Oblique (MLO) and CC views (with 34 kV and 250 mAs as exposure parameters).
In the 1st scenario, the TLD measurements did not detect significant dose values in the abdomen whereas the MGD estimated using the D.R. Dance model was in close agreement with data available in the literature. In the 2nd scenario, there was no significant difference in MGD estimation between the different views, whereas the air kerma values in the abdomen (in DBT mode, CC and MLO) were 0.049 mGy and 0.004 mGy respectively. In CC DM-2D mode the abdomen air kerma value was 0.026 mGy, with no significant detected value in MLO view.
For the dose in the uterus, the obtained values seem to indicate that DM-2D and DBT examinations inadvertently performed during pregnancy do not pose a significant radiological risk, even considering the case of overexposure in both breasts.
The accurate knowledge of the doses in DM-2D and DBT will contribute to raise the awareness among medical practitioners involved in breast imaging empowering them to provide accurate information about dose levels in the uterus, improving their radiation risk communication skills and consequently helping to reduce the anxiety of pregnant women undergoing this type of examinations.
数字乳腺 X 线摄影术（DM-2D）和数字乳腺断层合成术（DBT）是两种最有效的乳腺癌检测成像方式，常用于筛查项目。在这些成像方式的检查过程中，可能会意外地对孕妇进行检查。本研究的目的是根据两种主要照射情况评估因 DM-2D 和 DBT 检查而导致子宫内的剂量：在第一种情况下，由成像系统直接预选曝光参数，而在第二种情况下，选择最大曝光参数。
所使用的乳腺摄影设备是西门子 Mammomat Inspiration。使用物理人体模型体模、PMMA 板（模拟 6 厘米的乳房厚度）和热释光剂量计（TLDs）测量体模乳房和腹部的入口空气比释动能值，以依次估计乳腺腺体剂量（MGD）和子宫内的剂量。对于选择的两种照射情况，选择了两种乳房成像方式：1）DBT 颅尾位（CC）视图（曝光参数为 28 kV 和 160 mAs），2）DBT 和 DM 中侧斜位（MLO）和 CC 视图（曝光参数为 34 kV 和 250 mAs）。
在第一种情况下，TLD 测量未在腹部检测到明显的剂量值，而使用 D.R. Dance 模型估计的 MGD 与文献中提供的数据非常吻合。在第二种情况下，不同视图之间的 MGD 估计值没有差异，而腹部（在 DBT 模式下，CC 和 MLO）的空气比释动能值分别为 0.049 mGy 和 0.004 mGy。在 CC DM-2D 模式下，腹部空气比释动能值为 0.026 mGy，在 MLO 视图中未检测到明显值。
对于子宫内的剂量，获得的值似乎表明，即使考虑到双乳过度曝光的情况，在怀孕期间意外进行的 DM-2D 和 DBT 检查不会带来显著的放射风险。
准确了解 DM-2D 和 DBT 的剂量将有助于提高参与乳腺成像的医疗保健专业人员的意识，使他们能够提供关于子宫内剂量水平的准确信息，提高他们的辐射风险沟通技巧，从而有助于减少接受这种类型检查的孕妇的焦虑。
