Breast dosimetry

The estimation of the absorbed dose to the breast is an important part of t he quality control of the mammographic examination. Knowledge of breast dos e is essential for the design and performance assessment of mammographic im aging systems. This review gives a historical introduction to the measureme nt of breast dose. The mean glandular dose (MGD) is introduced as an approp riate measure of breast dose. MGD can be estimated from measurements of the incident air kerma at the surface of the breast and the application of an appropriate conversion factor. Methods of calculating and measuring this co nversion factor are described and the results discussed. The incident air k erma itself may be measured for patients or for a test phantom simulating t he breast. In each case the dose may be determined using TLD measurements, or known exposure parameters and measurements of tube output. The methodolo gy appropriate to each case is considered and the results from sample surve ys of breast dose are presented. Finally the various national protocols for breast dosimetry are compared. (C) 1998 Elsevier Science Ltd. All rights r eserved.