AUTHOR=Fitilis Ioannis , Grigoriadis Anastasios , Tazes Ioannis , Petrakis Stelios , Andrianaki Georgia , Dimitriou Vasilios , Bakarezos Efthimios , Benis Emmanouil P. , Tsiapa Irini , Boursianis Themistoklis , Kalaitzakis Georgios , Bontzos Georgios , Liakopoulos Dimitrios A. , Pappas Evangelos , Detorakis Efstathios T. , Clark Eugene L. , Maris Thomas G. , Papadogiannis Nektarios A. , Tatarakis Michael TITLE=Polymer-Gel Radiation Dosimetry of Laser-Based Relativistic Electron Sources for Biomedical Applications: First Qualitative Results and Experimental Challenges JOURNAL=Frontiers in Physics VOLUME=10 YEAR=2022 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.727511 DOI=10.3389/fphy.2022.727511 ISSN=2296-424X ABSTRACT=

The generation of laser based relativistic electron sources involves impressive basic science as well as innovative applications. This study reports first novel qualitative results on polymer-gel radiation dosimetry of ultrafast laser-based relativistic electron beams. The fabricated polymer-gels are irradiated by the ultra-high dose rate (FLASH) laser-generated electron beams and then are analysed using magnetic resonance imaging. The reading of the irradiated dosimeters is performed using a clinical 1.5 T Magnetic Resonance Imaging system. Three-dimensional colour parametric T2 maps are then constructed from the original PD-T2 weighted images obtained from the clinical MRI scanner. For comparison, the gels are also irradiated with standard electron beams of various energies utilizing a radiotherapy clinical linear accelerator system. For the calibration measurements of the gel dosimetry method, special calibrated dosimetric films are also implemented. The preliminary results demonstrate the potential of polymer gel dosimetry for 3D-dose-distribution of FLASH type irradiation of laser generated electron beams. Furthermore, they illustrate potential issues related to the polymer gel based dosimetry in challenging irradiation arrangements, such as the oxygen sensitivity and necessity for oxygen impermeable container material.