PURPOSE: To determine the normalized glandular dose ((D) over bar(gN))
for molybdenum target-rhodium filter (Mo-Rh) and rhodium target-rhodi
um filter (Rh-Rh) mammography and compare the average glandular doses
((D) over bar(g)) that resulted with a conventional molybdenum target-
molybdenum filter (Mo-Mo) source assembly. MATERIALS AND METHODS: X-ra
y spectra models for Mo-Rh and Rh-Rh were developed and used to calcul
ate (D) over bar(gN) values for these target-filter combinations as a
function of x-ray tube potential, half-value layer, and breast thickne
ss for three breast compositions. For the average glandular dose compa
risons, 50/50 phantoms were imaged for the three target-filter source
assemblies at three tube potentials. RESULTS: For the same parameters,
(D) over bar(gN) values for Mo-Rh and Rh-Rh were higher than for Mo-M
o. At the same voltage, the exposures required to image breast phantom
s are substantially lower, and as a result, (D) over bar(gs) are also
less with Mo-Rh and Rh-Rh than with Mo-Mo. CONCLUSION: (D) over bar(gN
) values presented permit practical evaluations of average glandular d
oses for Mo-Rh and Rh-Rh mammography. At a given potential, dose savin
gs are realized with Mo-Rh and Rh-Rh source assemblies.