Focal spot size and scatter suppression in magnification mammography.

The improved image quality using magnification in film-screen mammography is related to a complicated interplay between focal spot size, x-ray tube output, detector resolution and sensitivity, air gap size, and target dimensions. Preliminary clinical evaluation of magnification mammography indicates that accuracy of diagnosis has been considerably enhanced. Additional technical and clinical evaluations are continuing, as suggested by mathematical modeling, in order to determine the best possible magnification protocols. While a small focal spot (less than 300 micrometers) is highly recommended for both contact and magnification with the film-screen systems, the smallest focal spot sizes (150 micrometers and smaller) may neither be necessary nor the best in all situations of reduced dose magnification mammography.