X-ray scattering and attenuation cross-sections and coefficients of bone, brain, lung, fat, and soft tissue for applications in dosimetry, cancer detection, and treatment

Abstract

The Klein-Nishina electronic and atomic cross-sections and Compton mass attenuation coefficients of the bone, lung, soft tissue, brain, and fat are calculated for X-ray or γ-ray energies of 50 keV, 140 keV, 364 keV, 1.25 MeV, 4.784 MeV, and 6.0 MeV. The Klein-Nishina formula was used in the entire calculation. The results show that the Klein-Nishina electronic cross-section (eσ) decreases with increasing photon energy. Due to the complex variation in the effective charge number Z of the tissues, the Klein-Nishina atomic cross-section (aσ) first increases and then decreases for the investigated tissues. The Compton mass attenuation coefficient (σ/ρ) has even more complexity when the calculated values of σ/ρ are analyzed as a function of increasing Z/A for the investigated tissues. An overall trend of increase in σ/ρ is observed for increasing Z/A for all tissues except the cortical bone. In the case of the cortical bone, the values of σ/ρ decrease since cortical bone is a relatively high Z tissue as compared to other tissues where a rapid increase in the effective mass number A occurs when Z is increased. Overall, the results are very useful in calculating and delivering precise and optimum doses to avoid image quality degradation in radiographic images and to treat a tumor more effectively while keeping the normal tissues safe in radiation treatment planning.