DOSIMETRY IN CONTACT AND MAGNIFICATION MAMMOGRAPHY, USING MONTE CARLO SIMULATION

摘要

Magnification mammography is a technique used when breast complaints are noticed by a woman or when an abnormality is found in a screening mammogram. The carcinogenic risk in mammography is directly related to the dose deposited in the glandular tissue of the breast, rather than the adipose, and Average Glandular Dose (AGD) is the quantity taken into consideration. Direct measurement of the AGD cannot be performed during clinical practice and thus, normalization to the incident air Kinetic Energy Released per unit of MAss (KERMA) on the breast surface is used to estimate the glandular dose. In this study, the conversion factors for the case of both contact and magnification mammography are calculated, using Monte Carlo simulation. Moreover, the effect of different anode/filter material combinations on the percentage depth dose (PDD) and on the AGD was examined. Results demonstrate that, for fixed glandularity, the estimation of AGD utilizing conversion factors mainly depends on the magnification factor, the anode/filter combination and the tube voltage applied. Moreover, AGD and PDD where found to increase with the filter material k-absorption edge, the anode material kemission edge and the filter thickness.