Investigation of Mean Free Path, Macroscopic Cross- Sections, and Total Cross- Sections in Particle-Induced Reactions for Production of Theranostic 186Re Using Geant4

The study of Mean Free Path (MFP), Macroscopic Cross-Section (MCS) and Total Cross- Section (TCS) as a function of incident energy for particle induced reactions is receiving much interest due to their importance in applications, such as medical radionuclide production and optimization, radiotherapy, shielding design and geological dating studies. This paper investigated the MFP, MCS and TCS as functions of alpha, deuteron, proton and neutron particles on 186Os targets in order to model nuclear reactions for the production and optimization of theranostic radionuclides with the use of GEANT4, a C++ based Monte Carlo simulation toolkit that offers visualization, graphical user interface and several options to customize target geometry, size, beam energy as well as irradiation time. The findings reveal the shortest MFP to be 2.9 cm, peak MCS as 0.35 cm-1, and peak TCS was 0.34 b from neutron interactions at 2.5 MeV. For proton, deuteron and alpha particles interactions, their maximum MCS and TCS values manifest at energies in range between 17.5 MeV and 25 MeV which indicate apparent analogy in their behaviour in 186Os at high energies. Further, the results also reveal the excitation function datasets for the 186Os (n.p)186Re reaction which demonstrated good agreement with evaluated nuclear data files (ENDF) and experimental data (EXFOR). The new nuclear data will be invaluable for radiopharmaceutical manufacturers in producing 186Re to sustain the theranostic approach.