| Περίληψη: | Magnification mammography is a special technique used in cases where breast
complaints are noticed by a woman or when an abnormality is found in a screening
mammogram. The carcinogenic risk in mammography is 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 during a mammographic exam.
Direct measurement of the AGD is not feasible during clinical practice and thus, the
incident air Kinetic Energy Released per unit of MAss (KERMA) on the breast
surface is used to estimate the glandular dose, with the help of proper conversion
factors.
Additional conversion factors adapted for magnification and tube voltage are
calculated, using Monte Carlo simulation. The effect of magnification factor, tube
voltage and various anode/filter material combinations on AGD, ESD and PDD is
also studied.
Results demonstrate that, for fixed glandularity, the estimation of AGD
utilizing conversion factors depends on magnification factor, anode/filter combination and tube voltage applied. AGD was found to increase mainly with filter material’s kabsorption edge, filter’s Al thickness, anode material’s k-emission edge and tube voltage. Rh/Nb, W/Zr, W/Nb, W/Mo and Mo/Nb are combinations resulting in lower
AGD and higher ESD, compared to the Mo/Mo one.
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