Dosimetric and Biological Validation of a Proton Therapy Research Line using a Murine-Based Phantom

Abstract

During pre-clinical research on proton therapy, validating the dosimetry is important for accurate and representable results. To ensure that research outcomes can eventually be implemented in clinical practices, it is equally as important to also take biological effects into account. The aim of this thesis was, therefore, to dosimetrically and biologically commission a pre-clinical proton therapy research line. A phantom was designed, 3D-printed and irradiated to check accurate positioning in the beamline. Radiochromic film was used as a dosimeter at different positions within the phantom. The blackening of this radiochromic film after proton irradiations was quantified to obtain information on the dosimetry. It seemed that the phantom was correctly positioned at different places in the spread-out Bragg peak. However, accurate and precise dosimetry appeared to be difficult with radiochromic film. The added compensator successfully gave more uniform profiles throughout the whole depth of the phantom. Furthermore, the dose response of spheroids made from FaDu tumour cells was characterised and
compared to the dose response of cells grown as a monolayer. Spheroid growth and viability, based on the cellular ATP levels, were used as biological endpoints. A different dose response of FaDu spheroids was found when compared to that of cells, however, no clear explanation was found and more research remains to be done. Overall, with some further research, this 3D-printed phantom, along with the tumour spheroids, can
be implemented to validate a pre-clinical proton therapy research line.