Optically stimulated luminescent glass optical fibre dosemeter

An optical fibre radiation dosemeter has been developed that utilises optically stimulated luminescence and scintillation to provide independent, remote, real-time dose measurements. The radiation sensitive element consists of a 1 mm long, 0.4 mm diameter piece of copper-ion-doped fused quartz that is attached to a 1 m length of commercial optical fibre. The dosemeter probe is 0.6 mm in diameter and is flexible enough to be used in standard medical catheters for internal radiation dose measurements. A four-channel dosemeter system has been built and characterised under conditions typical of a radiotherapy environment. The device exhibits a linear response over the range of doses from 0.01 Gy to 10 Gy. The dosemeter responds identically to both electrons and photons in the range from 4 to 20 MV and the calibration was retained to within +/-2% over a period of 4 weeks. The fibre dosemeter has been used successfully to verity doses received by three patients receiving radiotherapy treatments.