An optical fibre dose imaging system for cancer radiotherapy
Over half of diagnosed cancer patients in Europe require some form of radiotherapy treatment. Delivering this medicine exactly where it is needed means lower doses are necessary, and any harmful side effects are reduced. Radiation treatment for cancer has become far more localised, through a process known as brachytherapy, where radioactive material is placed directly into the area of cancerous tissue. Yet clinicians still need to monitor the intervention in real time. The EU-funded ORIGIN project has created an innovative photonic-based imaging and localisation system for radiotherapy, which will significantly lower the risk of treatment error and improve patient outcomes. “The ORIGIN system was always developed with the patient at the fore, and the technical teams worked closely alongside the clinical teams to ensure it was designed in a way that meets the patients’ needs,” explains Sinead O’Keeffe, Royal Society – Science Foundation Ireland University research fellow at the University of Limerick and ORIGIN project coordinator.
Photonics-enabled brachytherapy
To measure the radiation, the team designed optical fibre sensors using a special radiation-sensitive material, known as a scintillator, which converts the radiation into visible light. The detector system measures the light emitted by the optical fibres. It is based on a 16-channel array, which allows the radiation dose to be measured at multiple points simultaneously. The multichannel detector system employs specialist technology known as a silicon photomultiplier, which enables the detection or ‘counting’ of single photons. “This provides both the sensitivity and range required for different brachytherapy treatments,” adds O’Keeffe. “When exposed to ionising radiation, the scintillating tip of the optical fibre sensor emits photons of light which travel along the optical fibre to the detector system.”
Enhancing accuracy with artificial intelligence
The accurate placement and measurement of the radioactive source during brachytherapy is crucial, both to guarantee the dose prescribed to the target area and to ensure minimum exposure to nearby organs. Here the team employed artificial intelligence to determine the location of the radiation source, by analysing dose readings from the optical fibre sensors, and combined this data with the position of sensors. A heat map can then be generated, which, when overlaid with the patient’s CT or ultrasound image, confirms the position and dose of the radiation being received.
From ORIGIN to clinical validation
Through the project, the team constructed 3D-printed models of the human pelvic area to eliminate the need for patients during trials to verify and develop the system. ORIGIN system prototypes were clinically evaluated by the project’s three clinical partners, the Blackrock Health Galway Clinic, Northern Ireland Cancer Centre and University Central Hospital of Asturias. “The overall ORIGIN system is the project’s main exploitable result, providing significant clinical impacts,” notes O’Keeffe. However some individual aspects have found applications beyond the original scope. The next step is to bring the ORIGIN system to the clinical validation stage. “While working closely with the clinical teams, the impact this system would have on patient outcomes in brachytherapy was continually conveyed,” says O’Keeffe. “As such, the whole team is eager to see the system rolled out in hospitals throughout Europe, and will continue to drive towards this goal.”
Keywords
ORIGIN, cancer, treatment, artificial intelligence, brachytherapy, optical, photonics, clinical
