Preliminary investigation of a reusable radiochromic sheet for radiation dosimetry

This work investigates a novel reusable radiochromic sheet developed as an economic film substitute or as a radiochromic bolus. The radiation-induced optical density (OD) change of the sheet is read-out with a commercial flat-bed optical scanner. An optimized readout procedure was developed including an optimal scan-time window. Fundamental radiochromic properties of the sheets were characterized including temporal decay of OD, dose sensitivity and consistency through repeated irradiations, and temperature sensitivity. The radiation induced OD change in the sheets was found to decay to baseline within ∼24 hours, after which the sheet could be reused. The sensitivity of subsequent re-irradiations was found to be consistent within ±5% (coefficient of variation of 4.5%) for at least 6 irradiations and potentially many more. Importantly, the sheets were not observed to carry any detectable memory of previous irradiations within measurement uncertainty. In conclusion, the Presage sheets show promise as an economic multi-purpose alternative for film applications and potentially as a radiochromic bolus. Further work is required to test the sheet in diverse clinical applications, and to develop a softer material for bolus applications. (paper)