[The film-mammographic demonstration of micro-calcification (author's transl)].

The smallest dimension (dmin) of circular, isolated micro-calcifications in breast tissue was studied in relation to the degree of calcification (weight-per cent-appetite), relative scatter and the film properties of screenless mammography films. From our own investigations on phantoms, the smallest signal-to-noise ratio (delta S min/delta R) was obtained which determines the minimal contrast, given the film properties (film response S, film gradient gamma) and the amount of scatter. An approximate formula for dmin has been derived which incorporates the ROC concept.