Theoretical investigation of radiation absorption properties of electrons, photons, and heavy ions in Fe-based shape memory biomedical alloys

Abstract

Shape memory alloys (SMAs) have many new applications in medicine today due to their ability to remember a specific geometry. However, the majority of SMAs are not biodegradable, resulting in serious surgical procedures to remove them when necessary. Similarly, the use of radiation applications for any diagnostic or therapeutic purpose affects the radiation dose distribution to the patient, leading to dosimetric errors due to scatter. Uncertainties in this dose distribution can lead to serious patient complications. In this study, the response and interaction mechanisms of four Fe-based SMAs (Fe-30Mn-5Si-CaP, Fe-23Mn-5Si, Fe-30Mn and Fe-5Pt) against X-ray and particle radiation used in diagnosis and treatment were analysed and interpreted using different theoretical software. To determine the reliability of the GAMOS algorithm in assessing the radiation absorption capacity of alloys, the Phy-X/PSD database was also used to obtain the radiation absorption parameters of alloys. The mean free path ( $ \lambda $ lambda), half-value layer (HVL), mass attenuation coefficient ( $ \mu /\rho $ mu/rho) and linear attenuation coefficient ( $ \mu $ mu) values, the energy exposure accumulation factors (EBF) and energy absorption accumulation factors (EABF) were analysed as radiation protection parameters. Stopping power and range data were also obtained from ESTAR (Stopping Power and Range Tables for Electrons) and SRIM (Stopping and Ranging of Ions in Matter) packages. These were used to understand the electron and heavy ion interactions of the SMA alloys. As a result, the radiation interaction mechanisms for photons and even for ions at different energy levels of the Fe-based shape memory biomedical alloys are quite different and their effect on the radiation dose distribution are remarkable.