OPTIMIZATION OF RADIATION-DOSE AND IMAGE QUALITY IN MAMMOGRAPHY - A CLINICAL-EVALUATION OF RHODIUM VERSUS MOLYBDENUM

Mammography was done with a conventional molybdenum anode/filter combi nation and either a molybdenum/rhodium (Mo/Rh) or rhodium/rhodium (Rh/ Rh) combination to compare the contrast characteristics and penetratin g ability of the different techniques. Each pair was rated as being eq ual, one slightly better than the other, or one much better than the o ther. The ''preferred'' image was also selected. The entrance surface exposure and the mean glandular dose were determined for each exposure . Mo/Mo was compared with Mo/Rh in 26 patients and to Rh/Rh in 23. Mo/ Mo was judged to produce better or equal contrast and penetration in a ll cases except one using the Mo/Rh combination. Mo/Rh was the preferr ed image only once and Rh/Rh not at all. In comparison to the conventi onal Mo/Mo technique, the average dose was reduced by approximately 25 % with Mo/Rh and by 50% with Rh/Rh.