Investigation of thin thermoluminescent films of mixed CaSO4 and P(VDF-TrFE) copolymers and its blends with PMMA for digital radiography

The thermoluminescence of [CaSO₄:Mn] have been explored to produce radiographic images when this material is mixed with pure ferroelectric poly(vinylidene fluoride-trifluorethylene) [P(VDF-TrFE)] copolymer blended with poly(methyl methacrylate) [PMMA]. These polymeric materials have been utilized mainly because of their good optical transparence, good resistance to ionizing radiation and heat diffusion. Thin thermoluminescent films (200μm) were prepared by casting and irradiated with gamma and X rays in the presence of human phantoms and metallic standards. The radiographic images were generated in a special device designed to heat the sample to CaSO₄:Mn main TL peak temperature (136°C). The emitted light was collected by a charged coupled device (CCD) camera. The good quality of the obtained radiographic images have demonstrated the feasibility of using TL materials immersed in polymeric matrix as an alternative way to obtain X ray digital images, which are commonly produced by photoluminescence phosphors and X ray sensitive CCD cameras. This investigation has shown that combining new high sensitive TL materials with CCD cameras which presents high response in the blue spectrum range could lead thermoluminescent films to show the same or even better performances than conventional digital radiographic devices.