Gel dosimetry is a 3D integrating dosimeter that offers high spatial resolution, precision and accuracy. Polymer gel dosimetry is founded on the basis that monomers dissolve in the gel matrix polymerize due to the presence of free radicals produced by the radiolysis of water molecules. The amount of polymerization that occurs within a polymer gel dosimeter can be correlated to the absorbed dose. The gel matrix maintains the spatial integrity of the polymers and hence a dose distribution can be determined by imaging the irradiated polymer gel dosimeter using an imaging modality such as MRI, X-ray Computed Tomography (CT), Optical Computed Tomography (OCT), Ultrasound and vibrational spectroscopy.