Contrast and dose with Mo-Mo, Mo-Rh, and Rh-Rh target-filter combinations in mammography.
OBJECTIVE
To study the effect of three mammography target-filter combinations on contrast and dose.


METHODS
With screen-film sensitometry, the contrast of a calcification target embedded in simulated breast tissue was measured for three target-filter combinations--molybdenum-molybdenum (Mo-Mo), molybdenum rhodium (Mo-Rh), and rhodium-rhodium (Rh-Rh)--as a function of x-ray tube potential, breast thickness, and breast composition. The corresponding average glandular tissue doses were also determined.


RESULTS
Contrast and dose decreased with increasing kilovolt peak with all three target-filter combinations. Contrast was highest for Mo-Mo and lowest for Rh-Rh for images exposed with a low kilovoltage (< 29 kVp). For thick or radiographically dense phantoms, the contrast produced with Mo-Mo was less than or equal to that produced by the other two x-ray spectra when a higher kilovoltage (> or = 29 kVp) was selected. Average glandular dose was greatest for Mo-Mo and lowest for Rh-Rh for all phantom thicknesses, breast compositions, and tube potentials studied.


CONCLUSIONS
For the thick or dense breast, the alternative target-filter selections can achieve contrast comparable to or better than that obtainable with Mo-Mo while using a smaller dose.
Gingold
E L
EL
Department of Radiology, University of Alabama Hospitals and Clinics, University of Alabama at Birmingham, USA.
Wu
X
X
Barnes
G T
GT
D001940:Breast / Q000528:radiation effects; D005260:Female; D006801:Humans; D008327:Mammography / Q000295:instrumentation*; D008961:Models, Structural; D008982:Molybdenum; D011829:Radiation Dosage; D012238:Rhodium; D013679:Technology, Radiologic / Q000295:instrumentation*
D008982:Molybdenum; D012238:Rhodium