Radiological Characterization of a Tissue-Equivalent Material for Trabecular Bone: From Diagnostic Imaging to Radiotherapy

Abstract

Author(s): Walid Allioui123*, Abdellah khallouqi1, Hamza Sekkat1, A. Slimani1, Abdellah halimi1, Omar El rhazouani1

The development of accurate trabecular bone-equivalent materials remains essential for improving the reliability of anthropomorphic phantoms used in medical imaging and radiotherapy. In this work, an epoxy–TiO? composite (75/25%) was developed and characterized over a wide photon energy range extending from 10 keV to 25 MeV. The evaluation combined theoretical calculations using the XCOM database, determination of effective atomic number and effective electron density using Phy-X/PSD, and experimental validation through computed tomography. At low energies (< 40 keV), the mass attenuation coefficient (μ/ρ) shows relative differences ranging from 8% to 14%, while Z_eff values remain close, with deviations within ±3% to ±5% around 10 keV. In the diagnostic energy range (50– 200 keV), μ/ρ values exhibit a strong agreement, with deviations generally below 2%, despite larger differences in Z_eff exceeding 20%. In this same range, N_eff values converge, with relative differences typically within 1% to 3%, supporting the similarity of photon interaction properties. At higher energies (> 200 keV), including the radiotherapy domain, μ/ρ values remain consistent within 1% to 4%, indicating stable attenuation behavior across extended energy conditions. Experimental CT measurements yielded Hounsfield Unit (HU) values between 226.9 and 296.8 HU, with an average of 271.2 HU, closely matching the clinical reference for trabecular bone (265.4 ± 3.2 HU). These results demonstrate that the developed composite provides a reliable approximation of trabecular bone and represents a cost-effective solution for applications in both CT imaging and radiotherapy dosimetry.

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