Sensor could prevent X-rays from damaging healthy cells

Doctors could avoid mistreating cancer patients undergoing radiotherapy with a new radiation detector under development at Bristol and Swansea universities.

The device will help prevent X-rays from hitting healthy tissue instead of tumours by alerting radiotherapists to any problems with the beam.

‘We are working on a detector based on very thin silicon camera systems that will not interfere with the radiation beam, but will provide the radiographer with an instantaneous real-time image of the beam as it is delivered,’ said Bristol’s Dr Jaap Velthuis.

‘This system will immediately detect inaccurate treatments, allowing any errors to be corrected before the patient suffers any adverse consequences. Costs of treatment will also be reduced as fewer mistreatments means more efficient patient care.’

Advances in radiation therapy mean tumours can be targeted more accurately, using devices called collimators to exactly adjust the shape and intensity of the radiation.

But faults can still occur once the beam is turned on and problem radiation isn’t easily detected. This has resulted in a significant number of mistreatments in recent years, particularly in the US, where adoption of the new technology has been more widespread.

The researchers are developing a device based on prototype sensors used to detect charged particles in physics research, and which is similar to sensors found in some mobile phones and cameras.

But this is the first time the technology is being used with X-rays. The device will be placed between the patient and the radiation source and will need to be very thin so it doesn’t affect the beam.

Estimates suggest it could measure just 0.0001 per cent of the radiation but this will depend on the thickness of the final model and even 0.1 per cent may be sufficient.

While the sensor’s hardware will essentially be the same previous devices, the team will also need to develop software that knows what to expect and can compare results quickly to enable the operator to identify problems and prevent mistreatment.

The National Institute of Health Research (NIHR), which funds research that benefits the NHS, is providing around £330,000 to support the 17- month project. The final device could be operational in hospitals within three years after completion of the prototype.