Novel silicon devices for radiation therapy monitoring

Modern radiotherapy techniques pose specific constraints in radiation-monitoring and dosimetry due to the occurrence of small radiation fields with high dose gradients, variation in space and time of the dose rate, variation in space and time of the beam energy spectrum. Novel devices coping with these strict conditions are needed. This paper reviews the most advanced technologies developed with silicon-based materials for clinical radiotherapy. Novel Si diodes as Pt-doped Si, epitaxial Si as well as thin devices have optimized performance, their response being independent of the accumulated dose, thus ensuring radiation tolerance and no need of recalibration. Monolithic devices based on segmented Si detectors can be easily tailored to optimize spatial resolution in the large active areas required in clinical radiotherapy. In particular, a monolithic device based on epitaxial p-type silicon, characterized by high spatial resolution and ability to directly measure temporal variations in dose modulation proved to be best viable solution for pre-treatment verifications in IMRT fields.