Abstract: A metal oxide field effect transistor (MOSFET) dosimeter developed by the Centre for Medical and Radiation Physics in Australia named the “MOSkin” is characterized in a clinical proton beam at Massachusetts General Hospital, Boston. The main advantage of the MOSkin is that it can be used as a pinpoint, real time dose verification tool for assessing the skin dose on patients receiving proton therapy. The detector has a 70 µm water equivalent thickness overlayer mimicking the skin depth of a patient. In order to characterize the MOSkin for proton therapy skin dose applications, several experiments have been conducted here at MGH at the Burr proton therapy center. The characterization of this detector includes a study of the dosimeters linearity, fading, angular dependence, as well its response to varying the voltage on the gate, along with a full pristine Bragg peak (BP) and clinical spread out Bragg peak (SOBP) depth dose curves which are benchmarked against a Markus ionization chamber and a 2D array of ionization chambers. While not all measurements have been fully analyzed and unpacked, some interesting results have been shown which will be presented along with the outlook for the device in a clinical setting.

About the speaker: My name is Vladimir Pan and I am a PhD student from the University of Wollongong in Australia, currently in Boston for 2 months to conduct experiments at the Proton Therapy Centre here at MGH. I began my studies at UOW in 2015 with a Bachelor of Medical and Radiation Physics, and after successfully completing my 4th year with First Class Honours, I undertook a PhD in 2019. I am currently 3.5 years into my studies and aim to finish within the next 6 – 12 months. My thesis is centered around silicon-on-insulator microdosimetry and its applications in particle therapy - specifically in RBE assessment, as well as radiation protection for astronauts in space. This talk however, will be focused towards the application of a MOSFET dosimeter, named the MOSkin, for skin dose verification during proton therapy, specifically for breast cancer patients as it is one of the main focuses for my visit here to MGH.