PURPOSE: To determine the normalized glandular dose (D̄(gN)) for molybdenum target-rhodium filter (Mo-Rh) and rhodium target-rhodium filter (Rh-Rh) mammography and compare the average glandular doses (D̄(g)) that resulted with a conventional molybdenum target-molybdenum filter (Mo-Mo) source assembly. MATERIALS AND METHODS: X-ray spectra models for Mo-Rh and Rh-Rh were developed and used to calculate D̄(gN) values for these target- filter combinations as a function of x-ray tube potential, half-value layer, and breast thickness for three breast compositions. For the average glandular dose comparisons, 50/50 phantoms were imaged for the three target-filter source assemblies at three tube potentials. RESULTS: For the same parameters, D̄(gN) values for Mo-Rh and Rh-Rh were higher than for Mo-Mo. At the same voltage, the exposures required to image breast phantoms are substantially lower, and as a result, D̄(g)s are also less with Mo-Rh and Rh-Rh than with Mo-Mo. CONCLUSION: D̄(gN) values presented permit practical evaluations of average glandular doses for Mo-Rh and Rh-Rh mammography. At a given potential, dose savings are realized with Mo-Rh and Rh-Rh source assemblies.
