New silicon-based detector for proton-beam cancer therapy in development

A team of researchers, from Proton Radiotherapy Verification and Dosimetry Applications (PRaVDA), are developing a new type of Silicon-based detector for eventual use within proton-beam cancer therapy.

Hopes are high for the new detector, as the researchers are aiming for it  to be developed and integrated into a series of new scanners that should provide physicians with a more accurate 3D image of any cancerous regions targeted for treatment.

Therapeutic proton-beams: the problem with CT scans

Currently, therapeutic proton-beams are guided to affected tissue areas via a preliminary CT scan (Computerised Tomography).  The collectedinformation from the CT scan is then used to calculate certain unique variables associated with any subsequent patient therapy (i.e. tumour location, beam energy, trajectory etc).

The problem with this technique is that a small, but non-negligible amount of uncertainty is introduced into the treatment. This means the proton-beam could affect regions of healthy tissue surrounding the tumour, making the current procedure less efficient and potentially more hazardous to patients.

How the problem could be solved

PRaVDA’s new detector is designed to eliminate these uncertainties: by utilising a complementary metal–oxide–semiconductor (CMOS) based array of sensors (DynAMITe – Dynamic range Adjustable for Medical Imaging Technology), an increasingly more accurate image of any cancerous regions can be obtained. Utilising specialised software, the sensors track proton trajectories through a patient’s body – and those paths can then be retraced back to the affected region to build up a more accurate three-dimensional picture of the tumour.

Whereas current calorimeter–based censors can only monitor single protons at any one time, DynAMITe, using its two pixelated wafer diode layers, can resolve multiple protons passing through the device; thus allowing increased localisation of ‘proton-sensor interactions’, as well as ‘spatial resolution’.

The future of proton-beam therapy

PRaVDA researchers plan to combine this technology into a ‘stack configuration’ that will hopefully be incorporated, along with other specialised sensors, into a series of new ‘proton transmission CT scanners’. The scanners will provide unique real-time imaging that will allow operating technicians to adjust and tailor therapeutic proton-beams to individual patient requirements (dose, energy, direction etc), without damaging surrounding healthy tissue.

Funding for the manufacture of two scanners has been received and should be operational in the not too distant future.

As PRaVDA states: ‘UK Department of Health confirmed in December 2011 that proton therapy will be made available for patients in the UK from 2017 via two new treatment centres, located in London and Manchester.


Credit: Paul Hattle

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