Evaluation of photon interaction parameters of Anti-HIV drugs

Medical treatment inevitably exposes individuals to radiation, including those taking drugs used to treat and prevent human immunodeficiency virus (HIV). Motivated by this, we investigated the radiation interaction properties of several HIV drugs to determine the interaction parameters, mass attenuation coefficient (MAC), atomic cross section (ACS), electronic cross section (ECS), effective atomic numbers (Zeff), and effective electron density (Neff). We calculated the values using the Phy-X/PSD software in the range of 0.015–15 MeV. Additionally, we calculated the exposure build-up factor (EBF), and energy absorption build-up factor (EABF) values of the drugs up to 40 mean free path (MFP) using the geometric progression (G-P) method. From our findings, we determined that Combivir, with its relatively high heavy element content, had the highest radiation attenuation capacity, whereas the probability of Lopinavir interacting with photons was the lowest compared with the other drugs. The results of the EBF and EABF parameters, including the scattering effects, ordered the drugs opposite to the primary interaction parameters such as MAC, ACS, ECS, and Zeff. These findings can guide the treatment process of HIV-positive patients and inform HIV prevention practices conducted alongside radiotherapy, as the interaction between radiation and a drug may cause deterioration in the drug's structure.