Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters

FACUNDO MATTEA; MARCELO ROMERO; JOSE VEDELAGO; ANDRES QUIROGA; MAURO VALENTE

APPLIED RADIATION AND ISOTOPES

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 100 p. 101 - 107

0969-8043

Polymer gel dosimeters have specific advantages for recording 3D radiation dose distributionin diagnostic and therapeutic medical applications. But, even in systems where the 3Dstructure is usually maintained for long periods of time after irradiation, it is still not possible to eliminate the diffusion of the different species in the regions of dose gradients within thegel. As a consequence, information of the dose loses quality over time. In the pursuit of asolution and to improve the understanding of this phenomenon a novel system based onitaconic acid and N, N?-methylene-bisacrylamide (BIS) is hereby proposed. Effects of changesin the chemical structure of the monomers over the dosimetric sensitivity and over the postirradiationdiffusion of species was studied. In this study, one of the carboxylic groups of theitaconic acid molecule was modified with aniline to obtain molecules with similar reactivitybut different molecular sizes. Then, dosimeters based on these modified species and on theoriginal ITA molecules were irradiated in an x-ray tomography apparatus at different doses upto 173 Gy. Afterwards, the resulting dosimeters were characterized by Raman spectroscopyand optical absorbance in order to study their feasibility and capabilities as dosimetricsystems, and by optical-CT to analyze the post irradiation diffusion.