FLASH-RT entails delivering a high dose over a sub-second timescale and exploratory experiments indicate cancerous regions suffer lethal damage whereas healthy tissues show little impairment. There has also been a recent publication on the first patient receiving such treatment with a dose rate of 15 Gy per 90 ms. FLASH-RT was shown to reproducibly spare normal tissues, while preserving the anti-tumor activity. This marked increase of the differential effect between normal tissues and tumors prompted its clinical translation. To achieve these dose rates conventional machines have been modified –and of course the delivery is far from optimal. We plan to investigate an optimised overall system design to achieve high dose rate.
Focusing, scanning and delivery of high dose rates with electrons will be the focus of this project. We have already shown electrons to be readily focused, steered, and to be insensitive to inhomogeneities and hence they are ideal for FLASH-RT. This research, will entail assessing the prospects for a robust machine design –entailing a moderate (with a view to a conservative reliable operation) gradient linac, RF source, magnets, a nd overall controls. This will necessitate a close collaboration with colleagues at ASTeC –as several aspects of expertise in this area will be sought to facilitate the design of a new machine.
The research in this area is limited but is clearly a very active and rapidly developing area. In addition to the relative insensitivity to inhomogeneities there may indeed be advantages of this technique over extant methods –such as more precise and rapid delivery to tumors with reduced fractionation (less patient visits needed with a more conformal high dose delivered). Indeed recent results in the area of ultra-high dose “FLASH” radiotherapy indicate considerable sparing of healthy tissue whilst in the presence of a high dose delivered very rapidly (sub-second).
Initially, the student will work with members of Prof. Jones’ VHEE group, and the potentially with the company Elekta, to become familiar with the control system and fundamental characteristics of a beamline. We also anticipate a strong collaboration with CERN colleagues –and with the CLIC group in particular who are fabricating compact high gradient linear accelerators which with suitable modification may serve as a prototype for a VHEE medical machine capable of delivering FLASH radiotherapy.
A major goal will be to investigate the dose profiles and beam penetration on simple specimens and later on more advanced biological samples. The groundwork for this experimental work will be laid down in the initial stages of the project through extensive simulations with advanced particle tracking codes –Topas/Geant4 in particular as we have in-house expertise on the use of this code. In addition to dose penetration studies the student will also investigate beam scanning and focusing both with extensive simulations and by designing and performing experiments at DL and at CERN’s CLEAR facility.