Couto Lilian Soares, Freitas-Junior Ruffo, Correa Rosangela Silveira, Peixoto João Emílio, Almeida Claudio Domingues, Rodrigues Danielle Cristina Netto, Glassman Leonard M, Soares Leonardo Ribeiro
São Marcelo Clinic, Goiânia-GO, Brazil. Mastology Program, Federal University of Goias, Goiânia-GO, Brazil.
J Radiol Prot. 2019 Apr;39(2):498-510. doi: 10.1088/1361-6498/ab0b28. Epub 2019 Feb 27.
Mean Glandular Dose (MGD) is the quantity related to the risk of radiation-induced breast cancer. This study aimed to evaluate the MGD in screening mammography for women with breast implants.
This retrospective study used data of 2680 mammographies of 335 asymptomatic women with mammary implants examined in a digital direct x-ray unit. Each woman had a total of eight images: four in standard views and four with posterior displacement of the implant (ID). Data on kV, mAs, target/filter combination, compressed breast thickness and MGD were obtained from the DICOM header of the stored images. Quantitative variables were presented through descriptive statistics for median (5th-95th percentiles); and the qualitative variables were presented by numbers and percentages. Mean glandular doses of standard views and ID views were compared and statistical analysis was used to assess the influence of implant position, breast glandularity and thickness on mean glandular doses.
Median MGD for standard views were 3.30 (2.60-4.00) mGy for CC and 3.31 (2.70-4.20) mGy for MLO. For ID views, median were 1.20 (0.90-2.20) mGy and 1.40 (0.97-3.74) mGy for CC and MLO views, respectively. Median MGD for the whole examination of women with breast implants was 9.60 (7.92-12.07) mGy, ranging from 6.25 to 21.50 mGy. When comparing MGD median for standard and ID views it was found a statistically significant difference (p < 0.05), with higher doses for the standard views due to the greater compressed breast thickness in these views. It was observed that, in the standard views, MGD decreases with increasing breast thickness due to the manual radiographic techniques used to expose the women. It was also observed that implant position does not affect MGD in breast augmentation mammography.
Mammography of women with mammary implants gives higher radiation doses when compared with those without implants. For more accurate dose assessment in augmented breast mammography, it is necessary that specific conversion factors for the calculation of MGD based on air kerma at entrance of breasts with implants are made available.
平均腺体剂量（MGD）是与辐射诱发乳腺癌风险相关的量。本研究旨在评估植入乳房假体女性的乳腺钼靶筛查中的平均腺体剂量。
这项回顾性研究使用了在数字直接X线设备上检查的335名无症状乳房植入假体女性的2680例乳腺钼靶检查数据。每位女性共有八张图像：四张标准视图图像和四张植入物后移（ID）视图图像。从存储图像的DICOM头文件中获取千伏（kV）、毫安秒（mAs）、靶/滤过组合、压缩乳腺厚度和平均腺体剂量的数据。定量变量通过中位数（第5-95百分位数）的描述性统计呈现；定性变量通过数字和百分比呈现。比较标准视图和ID视图的平均腺体剂量，并使用统计分析评估植入物位置、乳腺腺体密度和厚度对平均腺体剂量的影响。
CC位标准视图的平均腺体剂量中位数为3.30（2.60-4.00）mGy，MLO位为3.31（2.70-4.20）mGy。对于ID视图，CC位和MLO位的中位数分别为1.20（0.90-2.20）mGy和1.40（0.97-3.74）mGy。植入乳房假体女性的整个检查的平均腺体剂量中位数为9.60（7.92-12.07）mGy，范围为6.25至21.50 mGy。比较标准视图和ID视图的平均腺体剂量中位数时，发现存在统计学显著差异（p < 0.05），标准视图的剂量更高，因为这些视图中压缩乳腺厚度更大。观察到，在标准视图中，由于用于为女性进行曝光的手动放射技术，平均腺体剂量随乳腺厚度增加而降低。还观察到，在隆乳钼靶检查中，植入物位置不影响平均腺体剂量。
与未植入假体的女性相比，植入乳房假体女性的乳腺钼靶检查辐射剂量更高。为了在隆乳乳腺钼靶检查中进行更准确的剂量评估，有必要提供基于植入假体乳房入口处空气比释动能计算平均腺体剂量的特定转换因子。
