Characterisation of Glass Beads for Radiotherapy Dosimetry

Examinations have been made of a low cost commercially available material which is potentially useful as a dosimeter in radiotherapy. An investigation of the thermoluminescent (TL) yield and electron paramagnetic resonance (EPR) signal was performed by irradiating acid-washed glass jewellery beads to MV photons using a medical linear-accelerator and 60Co gamma rays. For comparison, irradiation exposures were also carried out on 5 mm length of Ge-doped optical fibres that have been widely investigated for their TL properties [1]. The dose response was linear for the investigated dose range of 1 to 2500 cGy, with an R2 correlation coefficient of > 0.999 and reproducibility of 1.7%. The results suggest the potential for use of glass beads as TL dosimeters in radiotherapy.