Purpose: To determine the composition of a breast phantom that is most suitable for phototimer testing.
Materials and methods: Kilovolt peak and milliampere second values were analyzed for phototimed exposures of phantoms containing 0%, 30%, 50%, 70%, and 100% simulated glandular material at thicknesses of 2, 4, 6, and 8 cm. Data also were analyzed from 1,578 mammograms in 417 patients. The mean effective glandular content of phantoms that simulated patient breasts of varying thicknesses was determined.
Results: Examination of mammographic techniques showed that the effective glandular content that simulated the average patient breast was 34%. Effective glandular content was 16% in breasts at least 7 cm thick when compressed; 26%, more than 5 to up to 7 cm thick; 42%, more than 3 to up to 5 cm thick, and 68% in breasts at most 3 cm thick.
Conclusion: A phantom composed of 30% glandular tissue and 70% adipose tissue allows closer simulation of the phototimer response of the mammographic x-ray unit for the average breast. The phantom currently used contains 16% more glandular tissue than the average breast.