A new generation of radiation dose detectors tailored for radiation treatment monitoring
Louis Archambault
Medical Physicist/Adjunct Professor
CHUQ/Laval University
Tuesday, October 2, 2012

Radiation treatments have considerably evolved in recent years. Today, radiotherapy employs complex dose distributions that are highly modulated in three dimensions. Furthermore, treatments can now be delivered dynamically by varying an array of parameters simultaneously such as the beam orientation, the dose rate and the shape of the beam aperture. In this context, traditional radiation dose detectors have increasing difficulties to accurately track radiation dose delivery. We are therefore motivated to develop new instruments specifically designed to monitor modern radiation treatments. Based on our past experience with plastic scintillation dose detector, we are investigating two novel detector concepts that would exhibits high spatial and temporal resolution as well as high measurement precision and accuracy.

By using multiple-scintillating elements emitting different wavelength spectra and a novel mathematical formalism akin the one used in hyperspectral imaging we have shown a way to optically encode spatial information within the scintillation signal thus allowing us to build a miniature detector array for real-time dose measurement capable of making readings at multiple locations simultaneously. In a second investigation, we have shown the feasibility of performing a tomographic acquisition of the scintillation signal produced within a large volume of scintillating material. With such a device, it is possible to reconstruct a complete, three-dimensional dose distribution after a single irradiation with a spatial resolution of the order of the millimeter.

While further work is required to bring these new instruments in the clinic, our work have shown their strong potential for answering the needs of modern radiation treatments. The use of these detectors will improve our confidence that complex, highly conformal treatments can be delivered accurately without risk to patients.