Monte Carlo assessment of peak-to-valley dose ratio for MRT

Small angle X-ray scattering experiments were conducted at the ID02 beamline of the ESRF to collect the form factors (FFs) of several biological tissues, among which were dry and fresh (wet) bone, as well as brain tissue. From the experimental data, the elastic diffusion cross-sections could be worked out and used for upgrading the cross-section libraries of the EGS4 code. A more accurate description of the radiation transport across biological samples is anticipated from the inclusion of the new values. The effect on the radiological dose deposited by arrays of planar microbeams to be used for therapeutic purposes has been evaluated. This technique is known as microbeam radiation therapy (MRT). In particular, we have focused on the dose profile which features valleys (between two consecutive peaks generated by the incoming microbeams) and peaks. The peak-to-valley dose ratio values obtained by using experimental data and via the independent atoms model (IAM) have been compared and critically discussed.