Radiology, Vol 163, 471-479, Copyright © 1987 by Radiological Society of North America
Screen-film mammographic technique for breast cancer screening
L Stanton, JL Day, T Villafana, CH Miller and DA Lightfoot
The values of dose and signal-to-noise ratio (SNR) for many techniques and
breast thicknesses were computed and compared with a reference technique
and breast thickness to provide a valid basis upon which to select a
screening technique for screen-film mammography. The reference consisted of
a Min-R/OM1 combination (or its equivalent) exposed through a 4.5-cm thick
breast via 28 kV and a molybdenum target- beryllium window tube with a
0.03-mm Mo filter. Radiographs of an improved breast phantom were used to
relate computed relative SNR values of techniques to diameters of the
smallest calcific and soft- tissue objects demonstrated in mammograms.
Without use of a grid, four Mo target/filtration combinations yielded
similar computed dose and SNR levels, as did a tungsten target tube
operated at 23 kV without a filter. Operation of the latter tube at 27.5 kV
with a 0.051-mm rhodium filter should reduce dose by half but also SNR by
22%. However, such operation with a grid should greatly improve imaging
moderate to large breasts without increasing dose over reference values.
