Experimental determination of linear attenuation coefficients using a CdTe detector: application to breast tissue-equivalent materials.

Tissue-equivalent materials play an important role in clinical radiography systems, as they must accurately simulate human tissue in quality control testing. Therefore, precise characterization of these materials is essential for developing reliable phantoms for applications in this field. This study aims to evaluate an experimental methodology for determining the distribution of mass attenuation coefficients (μ/ρ (E)) of materials at each energy of polyenergetic X-ray beams measured by X-ray spectrometry using a CdTe detector. Additionally, as a practical application, various resins were analyzed to identify materials equivalent to breast tissue. The methodology involves measuring X-ray spectra using a CdTe detector in a narrow beam geometry, both incident on and transmitted through materials of varying thicknesses. For each energy in the distribution, an attenuation curve is obtained from the measured X-ray spectra, and the linear attenuation coefficient is calculated. Four reference materials with varying densities and atomic numbers were evaluated for validation purposes: PMMA, aluminum, silver, and copper. The experimental μ/ρ (E) for the reference materials agreed with literature results, with a minimal average relative discrepancy of -0.5 % for PMMA and a maximum of 3.2 % for silver. Among the analyzed resins, at low energies, a mixture of UV resin with 15 % soft resin exhibited a mass attenuation coefficient curve closer to that of adipose tissue compared to the other resins. The methodology presents limitations in analyzing breast tissue-equivalent materials, as breast tissues exhibit very similar linear attenuation coefficient values, requiring high precision. However, its performance can be improved by acquiring spectra with a high number of counts, which reduces statistical errors. This method is effective for evaluating material equivalence in terms of mass attenuation coefficient across different types of tissue.