Quality Assurance Detector for Proton Beam Therapy

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Campus of University College London (Image credit: UCL)

A team of researchers from University College London, led by Professor Simon Jolly, has obtained a research grant from the UK’s Science and Technology Facilities Council (STFC) to fund the project QuADProBe: Quality Assurance Detector for Proton Beam Therapy.

In order to ensure that Proton Beam Therapy treatment is carried out safely, a range of quality assurance (QA) procedures are carried out each day before treatment starts. This means checking that the proton beam is in the correct position, is the right shape and size, and travels the correct depth: this must be checked for a range of different beam positions and energies to ensure treatment is safe. These QA measurements take significant time to set up and adjust for different energies: the full procedure can take over an hour.

QuADProBe is developing a detector that can make faster and more accurate measurements of the proton beam size, position and range than existing systems.
The detector is made of two parts. The first is a profile monitor made of two arrays of scintillating optical fibres, mounted at right angles to each other, which emit light when the proton beam passes through. This light can be measured with photodiodes to determine the beam size and position.
The second part, behind the profile monitor, is a detector built from layers of plastic scintillator. Protons passing through this scintillator stack deposit energy in each layer that is converted into light: by recording the light from each layer, the amount of energy the protons deposit along their path can be measured. Such a system provides a direct measurement of the range of protons in tissue, since the absorption of the plastic is virtually identical to human tissue.
This detector could allow the full morning beam QA procedure to be carried out in a few minutes, with an accuracy well below a millimetre in size, position and range. This would translate into being able to treat an extra 12 – 18 patients every day at the two new UK centres for Proton Therapy (at University College Hospital in London and The Christie in Manchester).

The QuADProBe project builds on the success of the QuARC scintillator range calorimeter, which was funded by an STFC grant and was originally developed through the work of OMA Fellow Laurent Kelleter. The project also benefited immensely from several OMA partners, including Cosylab and MedAustron.

The grant was awarded through the Challenge Led Applied Systems Programme (CLASP), which was established to support the application and commercialisation of STFC research in four key global research challenge areas: Energy, Environment, Healthcare, and Security.