Development and Characterisation of MOSFET Sensor for Dosimetry in DaRT and Proton Therapy

In modern radiotherapy, development of cancer treatment modalities has advanced to improve patient outcome, but new therapies come with various challenges for dosimetry and quality assurance (QA). In vivo dosimetry (IVD) is a methodology that monitors the actual dose independent to treatment planning system (TPS) by placing dosimeters on the patient skin, at a distance with build-up, or inside the patient. Comprehensive in vivo dose verifications are essential to identify major deviations in treatment delivery and even serve as patient QA but are not yet implemented during treatment. However, only a few radiotherapy centres worldwide include IVD during the treatment. MOSFET dosimeters are identified as advantageous for IVD given their small sensitive volume and real-time readout response. Dosimetric characteristics of MOSFET, such as linearity of doseresponse, sensitivity as a function of bias on the gate and fading response, are highly important for their application in radiotherapy. This thesis aims to characterise the MOSFETs that are developed and designed by the Centre for Medical and Radiation Physics, University of Wollongong, with three types of radiations for use as in vivo dosimeter.