A direct comparison of the optically stimulated luminescent properties of BeO and Al(2)O(3) for clinical in-vivo dosimetry

Optically stimulated luminescence dosimetry is a relatively recent field of in-vivo dosimetry in clinical radiotherapy, developing over the last 20 years. As a pilot study, this paper presents a direct comparison between the sensitivity variance with use, stability of measurement and linearity of the current clinical standard Al(2)O(3):C and a potential alternative, beryllium oxide. A set of ten optically stimulated luminescence dosimeters (OSLD), including five of each type, were used simultaneously and irradiated on a Versa HD linear accelerator. Having similar sensitivity, while Al(2)O(3):C showed a relatively stable signal response from initial use, BeO was found to have a higher response to the same dose. However, BeO displayed a strong exponential decline from initial signal response following a model of [Formula: see text] , reaching stability after approximately 10 irradiation cycles. BeO was shown to have potentially higher accuracy than Al(2)O(3):C, with less variation between individual doses. Both OSLD showed good linearity between 0.2–5.0 Gy. Between these bounds, Al(2)O(3):C demonstrated a strong linear response following the trend [Formula: see text] , however beyond this showed deviation from linearity, resulting in a measured dose of [Formula: see text] Gy at 10.0 Gy dose delivery. BeO showed strong linearity across the full examined range of 0.2–10.0 Gy with following a model of [Formula: see text] Gy with a recorded dose at 10.0 Gy delivery as [Formula: see text] Gy. In conclusion, BeO does show large variance in sensitivity between individual OSLD and a considerable initial variance and decline in dose–response, however after pre-conditioning and individual normalisation to offset OSLD specific sensitivity BeO provides not only a viable alternative to Al(2)O(3):C, but potentially provide higher accuracy, precision and reproducibility for in-vivo dosimetry.