Quality assurance and average glandular dose measurement in mammography units

To ensure the safe operation of mammography units, acceptance tests and quality assurance (QA) protocols have been developed by the American Association of Physicists in Medicine (AAPM), Engineers Registration Board, and International Atomic Energy Agency. Eight mammography units manufactured by five different manufacturers located in hospitals in our region were investigated following the AAPM and Atomic Energy Regulatory Board (AERB) protocols using a solid-state dosimeter-based PTW-NOMEX Multimeter and a metal-oxide-semiconductor field-effect transistor. This study evaluated different operating parameters through mechanical test, accelerating voltage (kVp) accuracy test, machine output measurement, half-value layer measurement, calibration of compression device, image quality assessment, measurement of leakage radiation, radiation survey, and average glandular dose (AGD) measurements using stereotactic needle biopsy phantom. The results show that out of eight mammography units, only a single mammography unit (U-1) passed all QA tests and 2 units passed 7 tests, 2 units passed 6 tests, and 3 units passed 5 tests out of 8 QA tests. In unit 5, the AGD value was 4 and 1.93 mGy before and after service, respectively. QA programs as recommended by AAPM and AERB should be carried out periodically to ensure safety in breast cancer screening. This work points to the importance of the regulation and effective compliance and also help in both improving the QA and reduce the glandular dose received by the patients. (author)