Detecting ionizing radiation dose using composite hydrogel-based sensors

Dose verification in radiotherapy is crucial to ensure a safe and efficient outcome of medical treatments. To overcome routine radiation dose detection challenges, a composite hydrogel sensor comprised of fluorescent poly( N -isopropylacrylamide)-based nanogels and clay nanoparticles is reported. The sensing methodology is primarily based on the transition of hydroxyphenyl fluorescein to fluorescence in the presence of OH radicals due to the radiolysis of water molecules under ionizing radiation, whereas the fluorescence intensity of 5(6)-carboxytetramethylrhodamine is stable upon radiation. Harnessing the ratiometric fluorescent strategy, in vitro point- and topographical-dose profiles under X-ray and electron beam irradiation and the in-vivo determination of γ-ray dose are determined without any waiting time after irradiation. The determined dose is comparable to the results of Monto Carlo simulations and clinical treatment planning systems (TPS). Also, the sensing capability of the developed sensor is well maintained, regardless of the types of radiation, dose rate, radiation energy, testing temperature, and storing period. Hence, our sensors show the translational potential for dose verification in radiotherapy.