Measurement of spectra in mammography using different phantoms

Evaluation of the performance of mammographic equipment requires the imaging and interpretation of test objects or phantoms and risk assessment. This study evaluated, using a spectrometry technique, the linear attenuation coefficients determined from transmitted intensity for commercially available tissue-equivalent phantoms for mammography, namely the Computerized Imaging Reference Systems (CIRS) phantom with different glandularity–adipose contents and PMMA. The measurements were performed using X-ray beams produced by Mo/Mo, Mo/Rh, and W/Rh target/filter combinations. The results are presented for the characteristic X-ray photopeaks (Mo Kα 1 at 17.48 keV and Mo Kα 2 at 19.61 keV). Spectrometry measurements were carried out using an Amptek XR-100T Cadmium Telluride (CdTe) detector, and the spectra were corrected using MCNP6 simulations. This work demonstrates the adequacy of the results obtained for Mo Kα 1 at 17.48 keV when compared with publications that applied different methods of analysis. In addition, it presents the evaluation of the attenuation coefficient for Mo Kα 2 at 19.61 keV for the CIRS phantom and its comparison with PMMA results.