Suleiman Moayyad E, Brennan Patrick C, Ekpo Ernest, Kench Peter, McEntee Mark F
1 Medical Radiation Sciences, The University of Sydney, Faculty of Health Sciences. Cumberland Campus , Lidcombe, NSW , Australia.
Br J Radiol. 2018 May;91(1085):20180032. doi: 10.1259/bjr.20180032. Epub 2018 Feb 13.
This work proposes the use of mammographic breast density (MBD) to estimate actual glandular dose (AGD), and assesses how AGD compares to mean glandular dose (MGD) estimated using Dance et al method.
A retrospective sample of anonymised mammograms (52,405) was retrieved from a central database. Technical parameters and patient characteristics were exported from the Digital Imaging and Communication in Medicine (DICOM) header using third party software. LIBRA (Laboratory for Individualized Breast Radiodensity Assessment) software package (University of Pennsylvania, Philadelphia, USA) was used to estimate MBDs for each mammogram included in the data set. MGD was estimated using Dance et al method, while AGD was calculated by replacing Dance et al standard glandularities with LIBRA estimated MBDs. A linear regression analysis was used to assess the association between MGD and AGD, and a Bland-Altman analysis was performed to assess their mean difference.
The final data set included 31,097 mammograms from 7728 females. MGD, AGD, and MBD medians were 1.53 , 1.62 mGy and 8% respectively. When stratified per breast thickness ranges, median MBDs were lower than Dance's standard glandularities. There was a strong positive correlation (R = 0.987, p < 0.0001) between MGD and AGD although the Bland-Altman analysis revealed a small statistically significant bias of 0.087 mGy between MGD and AGD (p < 0.001).
AGD estimated from MBD is highly correlated to MGD from Dance method, albeit the Dance method underestimates dose at smaller CBTs. Advances in knowledge: Our work should provide a stepping-stone towards an individualised dose estimation using automated clinical measures of MBD.
本研究提出使用乳腺钼靶摄影密度（MBD）来估计实际腺体剂量（AGD），并评估AGD与使用丹斯等人的方法估计的平均腺体剂量（MGD）相比情况如何。
从一个中央数据库中检索出匿名乳腺钼靶图像的回顾性样本（52405例）。使用第三方软件从医学数字成像和通信（DICOM）头文件中导出技术参数和患者特征。使用LIBRA（个体化乳腺放射密度评估实验室）软件包（美国宾夕法尼亚大学，费城）来估计数据集中每张乳腺钼靶图像的MBD。使用丹斯等人的方法估计MGD，而通过用LIBRA估计的MBD替代丹斯等人的标准腺体密度来计算AGD。采用线性回归分析来评估MGD与AGD之间的关联，并进行布兰德 - 奥特曼分析以评估它们的平均差异。
最终数据集包括来自7728名女性的31097张乳腺钼靶图像。MGD、AGD和MBD的中位数分别为1.53、1.62 mGy和8%。当按乳房厚度范围分层时，MBD的中位数低于丹斯的标准腺体密度。MGD与AGD之间存在强正相关（R = 0.987，p < 0.0001），尽管布兰德 - 奥特曼分析显示MGD与AGD之间存在0.087 mGy的小的统计学显著偏差（p < 0.001）。
从MBD估计的AGD与丹斯方法得出的MGD高度相关，尽管丹斯方法在较小的乳房压缩厚度（CBT）时低估了剂量。知识进展：我们的工作应为使用MBD的自动化临床测量进行个体化剂量估计提供一个垫脚石。
