Work

Comparative evaluation of mass attenuation coefficients and energy absorption parameters in human tissues across a broad photon energy range

Year: 2026

Type: article

Abstract: Reliable photon attenuation data are fundamental to medical physics for characterizing radiation transport, dose deposition, and shielding requirements within biological media. This study provides a comprehensive evaluation of the mass attenuation coefficient (MAC) across twelve human tissues representing distinct anatomical profiles: skeletal cortical bone, brain, blood, lung, heart, liver, ovary, muscle, thyroid, spleen, pancreas, and kidney. Computational calculations were performed using the XCOM database and the Phy-X/PSD platform over a broad photon energy range spanning from 1 keV to 100 GeV. The theoretical framework builds upon the classical exponential attenuation law, the mixture rule for composite media, and the breakdown of total attenuation into photoelectric absorption, Compton scattering, and pair production, alongside secondary evaluations of mass energy-absorption coefficients and kerma. The computed values were validated against available historical experimental datasets. The results reveal a uniform energy-dependent trend characterized by high low-energy attenuation values driven by the photoelectric effect, followed by convergence in the intermediate energy region where Compton interactions predominate, and eventual stabilization at high energies due to pair-production thresholds. Cortical bone demonstrated the highest MAC values under low-energy conditions due to its calcium and phosphorus content. Conversely, soft tissues exhibited highly uniform, closely matched attenuation profiles at high energies, with MAC values stabilizing around 0.0164–0.0171 cm 2 g −1 between 40 and 100 MeV. The close alignment between XCOM, Phy-X/PSD, and experimental values establishes the practical utility of these computational engines for clinical modeling, external beam radiotherapy planning, diagnostic optimization, and radiation protection training.

Source: Journal of Radiation Research and Applied Sciences

DOI: 10.1016/j.jrras.2026.102707