Investigation of radiation interaction parameters for some essential biomolecules

A biomolecule is a building block not only for humans but also for all the living organisms including animals and plants. In this dissertation, the radiation interaction properties of some essential biomolecules such as creatinine hydrochloride (creatinine H), methionine, glycoprotein, glycine, proline, margaric acid, tyrosine, inosine, and lactose were investigated by using the Geant4 simulations and some theoretical approaches. The photon interactions are studied by evaluating different important parameters such as linear attenuation coefficients (μ), mass attenuation coefficients (μm), effective atomic number (Zeff), and effective electron density (Neff) over a wide range of energy varying from 1 keV to 1000 MeV. The μm values were compared with the theoretical calculations performed via the XCOM program. In addition, the photon energy-absorption processes, which are influential mechanisms for the photon – biomolecule interactions, were investigated. Furthermore, the G-P method was applied to evaluate the photon exposure build-up factor (PEBF/EBF) and photon energy-absorption build-up factor (PEABF/EABF) which are related to the exposure in the air and medium, respectively. Additionally, the charged particle interactions with the selected biomolecules were studied by determining the electron stopping power, and the effective atomic number for electron, proton, alpha particle, and carbon ion for kinetic energies in the range of 0.015 – 15 MeV. The present work gives a full understanding, rich information, and important data for the radiation interactions with the biomolecules involved. Such data are expected to be used in dose calculations for both X / gamma rays and charged particle radiations.