Application of the 'Spiking' method to the measurement of low dose radiation (≤ 1 Gy) using alanine dosimeters

Alanine dosimeters are limited in radiotherapy by poor sensitivity at low doses (< 5 Gy). A set of alanine dosimeters were 'spiked' with a large dose of radiation, (~30 Gy, 6 MV X-rays) and additional doses ranging between 0.5 and 10 Gy. The radical yield was measured by Electron Paramagnetic Resonance (EPR) spectroscopy, and after subtraction of the contribution from the "spike" dose, a linear correlation between the radiation dose and the area of the central EPR signal was obtained for doses between 0.5 and 10 Gy (regression value of 0.9890), and for the central peak's amplitude (regression value of 0.9895). Overall, this method is easy to perform, requires no complex EPR signal analysis, and offers much potential to extend the current usage of alanine dosimeters in radiotherapy.