Preliminary results of synchrotron radiation dosimetry and putative impact on biological samples in mogno (micro/nano tomography) beamline

Full text: Longitudinal experiments are crucial to study biological dynamics in living samples. Among several techniques, bioimaging is a paramount for cellular biology up to systemic events. On the other hand, these samples are highly sensitive to ionizing radiation. Therefore, synchrotron radiation damage is a concern for biological tissue. It's important to understand the effects from cellular scale to the whole organism as well as to distinguish significances between whole body irradiation and partial exposure (tissues or cells). The Mogno micro and nano tomography beamline will have a multilayer KB mirror with a conical and quasi-monochromatic beam with three energy setups: 22, 39 and 67.5 keV; with FOV from 120 nm x 120 nm to 85 mm x 85 mm. The high brightness of synchrotron light at Mogno beamline makes it possible to obtain high spatial and temporal resolution and to improve the image contrast. However, it also increases the amount of energy deposited in the sample. The in-depth knowledge of biological effects passes through computational dose deposition simulations in different scenarios as well as experimental measurements. The radiation dosimetry calculations are being conducted in FLUKA and PENELOPE Monte Carlo (MC) codes to help planning a setup for experimental study with thermoluminescence (TL) and optically stimulated luminescence (OSL) dosimeters. Preliminary results show optimistic scenarios for bioimaging with dose-rate from 10-4 to 103 Gy/s/350mA. The dose rate at samples can be correlated with the damage in cells and explanted tissues. Results obtained in Geant4-DNA simulations will be compared to the experiments with yeast, high-dose resistant bacteria and eukaryotic cells intended to quantify the impact in cellular metabolism, respiration, DNA and chromosomal damage. Ultimately, all these steps will support the forthcoming experimental setup with in vivo small rodents. (author)