Comparison of Dance and AAPM/EFOMP TG282 breast dosimetry methodologies for a screening population: Evaluation of model-based median breast density metrics

Background

Accurate mean glandular dose (MGD) estimation is important in breast cancer screening programs to balance diagnostic benefit with radiation risk.

Purpose

This study aimed to compare the performance of the Dance and AAPM/EFOMP Task Group 282 (TG282) breast dosimetry methodologies using model versus image-derived breast density metrics.

Methods

This study analyzed over 80,000 digital mammography images acquired in 2023 from BreastScreen Queensland (BSQ). Data were obtained from Siemens and Hologic systems and included 2D cranio-caudal and mediolateral oblique views. Images with compressed breast thickness (CBT) between 20 and 100 mm were included. Volumetric breast density (VBD) and glandularity were extracted using Volpara software. MGD was estimated using both Dance and AAPM/EFOMP TG282 models, employing model-based median and image-measured breast density metrics. The ratios of MGD estimated using model medians to those using measured values ($R_{\mathrm{Dance}}$ and $R_{\mathrm{TG}282}$) were analyzed across CBT, and Pearson correlations (r) were computed.

Results

The Dance model median glandularity overestimates population-derived glandularity for most CBT, resulting in $R_{\mathrm{Dance}}$ > 1 at low CBT, with the trend reversed for CBT > 80 mm. $R_{\mathrm{Dance}}$ showed moderate positive correlation with CBT (r = 0.57 Hologic; r = 0.63 Siemens, p < 0.001). $R_{\mathrm{TG}282}$ remained close to unity across CBT, with weak negative correlations (r = −0.17 Hologic; r = −0.04 Siemens, p < 0.001), indicating consistency between model and measured VBD.

Conclusions

The AAPM/EFOMP TG282 dosimetry model exhibited stronger agreement between median model-predicted and population-specific measured breast density metrics than the Dance model. This resulted in improved consistency in ratios of estimated MGD values based on median model-to-measured breast density metrics across the full range of CBT, when using the AAPM/EFOMP TG282 methodology.