An investigation of the thermoluminescence of Ge-doped SiO2 optical fibres for application in interface radiation dosimetry

We investigate the ability of high spatial resolution (∼ 120 μm) Ge-doped SiO2 TL dosimeters to measure photoelectron dose enhancement resulting from the use of a moderate to high-Z target (an iodinated contrast media) irradiated by 90 kVp X-rays. We imagine its application in a novel radiation synovectomy technique, modelled by a phantom containing a reservoir of I2 molecules at the interface of which the doped silica dosimeters are located. Measurements outside of the iodine photoelectron range are provided for using a stepped-design that allows insertion of the fibres within the phantom. Monte Carlo simulation (MCNPX) is used for verification. At the phantom medium I2-interface additional photoelectron generation is observed, ∼60% above that in the absence of the I2, simulations providing agreement to within 3%. Percentage depth doses measured away from the iodine contrast medium reservoir are bounded by published PDDs at 80 kVp and 100 kVp.

▶ Studies of dosimetric characteristic of commercially available doped silica optical fibres. ▶ Investigation of the potential of the dosimeter in dose enhancement measurement. ▶ Use of photoelectron dose enhancement as might be applied in radiation synovectomy. ▶ Measurement of the percentage depth dose recorded by Ge-doped silica optical fibres. ▶ The Monte Carlo simulation provides comparison against measured data.