The work within ORIGIN was centred on two main areas, System Development and Manufacturability, and Clinical Integration, each with specific challenges associated with them:
SYSTEM DEVELOPMENT AND MANUFACTURABILITY
To measure the radiation, optical fibre sensors have been designed with a special radiation-sensitive material, known as a scintillator, which converts the radiation into visible light. Although the scintillating material differs for LDR and HDR brachytherapy, the design of the probes are identical. Therefore, the same fabrication process and equipment can be used, increasing the manufacturing efficiency and decreasing costs.
The detector system, which measures the light emitted by the optical fibres, has been developed to meet the needs of the differing radiation profiles of LDR and HDR brachytherapy. Both detector systems are based on a 16-channel array which allows the radiation dose to be measured at multiple points simultaneously. The multi-channel detector systems employs specialist technology known as silicon photomultiplier (SiPM), which enables the detection or “counting” of single photons. This provides both the sensitivity and range required for different brachytherapy treatments. When exposed to ionising radiation the scintillating tip of the sensor emits photons of light which travel along the optical fibre to the detector system.
Accurate placement and measurement of the radioactive source during brachytherapy is crucial to guarantee the dose prescribed to the target area, whilst also ensuring minimum exposure to nearby organs. Using artificial intelligence, the dose readings from the optical fibre sensors, combined with the sensors’ position, provided by an electromagnetic tracking system, enables the determination of the location of the radiation source(s). 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.
CLINICAL INTEGRATION
A careful consideration of the ORIGIN system development has been to ensure it is compatible with existing clinical practice and equipment. Several custom made devices have been designed to enable the ORIGIN sensors to be secured within existing brachytherapy applicators. Models known as phantoms, constructed using 3D printing technology, were developed to mimic the human pelvic area and enable the examination of dose measurements in anatomically correct models. The ORIGIN system prototypes were clinically evaluated by the project’s three clinical partners, Blackrock Health Galway Clinic, Northern Ireland Cancer Centre, and University Hospital of Asturias. A protocol for the integration of the ORIGIN system with existing treatment planning systems was developed for prostate and gynaecological HDR and LDR brachytherapy.
