Implantable in vivo Dosimetric Probe Based on GaN Radioluminescence

Abstract

This paper presents an implantable in-vivo dosimetric probe using a small-volume GaN bulk as scintillator. The high light yield of GaN under irradiation in radiotherapy conditions is observed. Heavily-doped n-type GaN is chosen because of enhanced and dominant UV emission. The fabrication process of the probe is described. It is tested using 6 and 18MV photon beams. Measured results show reproducibility errors of less than 2% for a delivered dose of 50cGy. The linearity of the measure and its independence of the dose rate are also verified. The probe’s output light has both GaN and fiber contributions. The fiber contribution may vary with the beam incidence angle (due to dominant Cerenkov effect), while the GaN does not have such dependence.