Development of real-time dosimetry methods for VHEE FLASH Radiation Therapy

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Cancer is a critical societal issue. Worldwide, in 2018 alone, 18.1 million cases were diagnosed, 9.6 million people died and 43.8 million people were living with cancer. Current projections anticipate an increase with approximatively 24,6 million newly diagnosed patients and 13 million related deaths by 2030.Ever since the discovery of X-rays in 1895, they played key role in cancer treatment. The beams of high-energy particles are known for depositing their kinetic energy when entering and propagating through matter. In radiotherapy (RT), this property of beams is used for the treatment of tumour's, since the deposited energy can damage and kill the tumour cells. Different particle types have been used for this purpose - photons (most common type of RT), electrons, neutrons, protons and heavy ions. RT is now a fundamental component of effective cancer treatment and control. The most frequently used modality of RT uses high-energy (6 to 10 MeV) photon, and in a small proportion low to intermediate energy (3 to 25 MeV) electron beams. The main challenge of RT is that the dose delivered to a tumour is limited by the dose that can be tolerated by the surrounding normal tissues.On the other hand, conventional photon RT is characterised by almost exponential attenuation and absorption, and consequently delivers the maximum energy near the beam entrance, but continues to deposit significant energy at distances beyond the cancer target. The maximum dose for photons beams with an energy of about 8 MeV, is reached at a depth of 2-3cm of soft tissue. RT is by far the most cost-effective modality for cancer treatment with the added advantage of conserving normal tissue function. The Global Task Force on Radiotherapy for Cancer Control (GTFRCC) estimated that 12,600 megavolt-class treatment machines will be needed to meet demand in LMICs by 2035 (there are currently only 385 machines) .Aims and Objectives.The STELLA (Smart Technologies to Extend Lives with Linear Accelerators) project will identify the fundamental specifications for an advanced X-ray RTT system for application in the challenging environments. A suitable electron-beam accelerator will be developed which matches these requirements, incorporating modern principles and technologies which are able to provide robust operation and modularized implementation.For the accelerator, modular options for the linear accelerator (linac) will be explored, which will be simpler and cheaper to maintain. These will include assessments of; a) The feasibility of a modular electron gun design to be simply separated from the linac structure for easy servicing/replacement to increase reliability and lifetime. b) Novel open linac structure solutions which could be substantially cheaper to manufacture and remove requirement for tuning post manufacturing. c) A new compact RF sources to power the linac, to minimise the physical size of the machine. d) Solutions for turn-key RF systems that is simpler for hospital engineers to replace. e) Ways to minimise the impact of highly variable electricity supply and determine improved methodologies. f) Improved modularity for local control and remote monitoring to predict common failure modes and minimise down time. g) The main causes of failure in RTT systems to perform statistical analysis of data provided by several hospitals in ODA countries. Similar issues are found in the Modulators, Klystrons, RF cavities and electron guns in CLARA at Daresbury and it can be used as a test bed for these studies. The student will work in collaboration with by ASTeC (technical lead for STELLA prototyping).