ABSTRACT
The history of development of radiochromic materials dates back to the early nineteenth century before discovery of X-ray by Roentgen and prior to the use of conventional silver halide-based radiographic films for radiographic imaging and radiation dosimetry. The radiochromic processes always involve the direct coloration of a material by the absorption of electromagnetic radiation, without requiring latent chemical or thermal development or amplification. The materials in the radiochromic films that are responsible for the coloration are known as crystalline polyacetylenes, in particular diacetylenes, and upon thermal annealing or radiation exposure they undergo polymerization, turning blue or red depending on their specific composition. In 2004, a more sensitive radiochromic film, external beam therapy (EBT) film, was introduced that was several orders of magnitude more sensitive than previous RCF models. EBT-XD film construction may also lend itself to better uniformity in the lateral scanning direction of desktop scanners as it should provide lower light scattering and polarization effects compared with EBT3 film.
