Investigation of relaxation times of irradiated Fricke gels by means of nuclear magnetic resonance relaxometry

Fricke gel dosimeters are ideal candidates to provide 3D maps of dose distributions and are particularly useful in the plann ing and verification phase of radiotherapy treatments. One of the most effective experimental techniques to reconstruct dose maps is magnetic resonance imaging (MRI). This measures th e nuclear relaxation times variations induced by irradiation. In this work, we analyzed Fricke gels with and without Xylenol Orange by means of a single side-NMR relaxometer (which is abl e to provide information on both relaxation relaxation times T1 and T2 and is mainly used in the field of diagnostics for Cultural Heritage [1-2] to perform porosimetry meaurements). Our goal was to perform a more basic investigation on the MR relaxation features of these gels with and without xylenol orange in order to achieve a deeper understanding of the physical properties of these gels from the relaxation times.