Delivering and Measuring FLASH radiotherapy

Worldwide interest in the transformative potential of Flash radiotherapy (RT) at high doses and dose rates >40 Gy/s stems from experimental results that appear to show that Flash RT kills the tumour whilst significantly reducing the damage to the healthy cells surrounding it. It is damage to these healthy cells that leads to RT induced side-effects which can have life-changing effects for patients.
This project aims to develop novel, non-destructive detector technology in the new accelerator environment of the proton therapy research room at the Christie. This room was designed through collaboration between the Precise group (UoM / Christie) and the Cockcroft Institute and represents a state of the art environment for investigating the parameters and delivery of clinical proton beams (70 MeV-250 MeV). This project seeks to accurately measure the dose and dose rate during proton beam ultra-high dose rate FLASH delivery. The first stage of this will use standard detector dosimetry techniques such as film, TLDs and alanine pellets which all need additional processing before getting a reading. The second stage will use real-time advanced detectors with the aim of achieving real time dosimetry measurements. Research will take place using high energy proton beams in the PBT research room at the Christie. This will involve working alongside the PBT research room engineer and Varian engineers to deliver FLASH PBT dose rate beams in the UK for the first time. Optimising the parameters of the cyclotron, beamline and beamline delivery system and magnets to optimise accelerator parameters to deliver FLASH beams and then developing the detector technologies to accurately measure them.
Initially, we would plan to do this in the PBT research room at the Christie, but the technology could also be applied to very high energy electrons (VHEE) or laser-induced high dose rate beams of photons, electrons, protons and ions. Accurate knowledge of the dose being delivered to the patient is crucial in all forms of RT but for Flash delivery, the high dose rate presents an added challenge and at the moment uncertainty measurements are about 4% [10-11]. This project will combine Monte-Carlo radiation transport calculations with empirical measurements in the PBT research room at the Christie to investigate the performance of detectors. It will then go on to look at other forms of Flash delivery collaborating with other groups at the Cockcroft Institute. The aim would be, given the current uncertainties to develop new detectors to measure Flash doses and dose rates, in real time with an uncertainty of around 1%