Screen-film mammographic technique for breast cancer screening.
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.
D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D004560:Electricity; D005260:Female; D006801:Humans; D008163:Luminescent Measurements; D008327:Mammography / Q000295:instrumentation / Q000379:methods*; D008433:Mathematics; D008961:Models, Structural; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation; D013679:Technology, Radiologic; D014963:X-Ray Intensifying Screens