Novel dosimetric gels for three-dimensional dose mapping in radiotherapy

One of the most recent and promising developments for radiotherapy (RT) dosimetry was the introduction of 3D radiation- sensitive gels. The gels are tissue equivalent, so they also serve as a phantom, and their response is largely independent of rad iation quality and dose rate. Some gels are infused with ferrous sulfate and rely on the radiation-induced oxidation of ferrous ions to ferric ions (Fricke-gels) . These gels suffer from spontaneous-oxidation and diffusion of ferric ions after irradiation; the latter is significantly reduced by chelating agents such as xylenol orange (XO) (Fricke-XO gels) [2]. Other formulations consist of dispersed monomers, and rely on radiation-induced cross-linking [3]. They develop into stable polymer structures, but they are often affected by significant toxicity. Recently, poly- vinyl alcohol (PVA) was identified as an alternative, promising matrix [4]. This work investigated new formulations based-on or loaded-with PVA, which are easy to manufacture and provide some of the most stable and sensitive gels available. In an extremely recent and original development, some of these gels can also be reset and reused.