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Radiation dosimeter uses light emissions

A device that measures radiation dosing in people or environments was developed by Sonia Tatumi, a physicist from the Federal University of São Paulo (Unifesp), Baixada Santista campus, jointly with Professors Marcio Yee and Juan Carlos Mittani from the São Paulo State Technological College (Fatec) in São Paulo. The device, a luminescent dosimeter that can be used for healthcare applications or in nuclear plants, consists of crystals produced from aluminum oxide doped with rare earths (ytterbium, erbium, neodymium, and praseodymium) and semimetals. “We noticed that these doping materials form nanocrystals, which are essential for increasing the luminescence emission,” says Tatumi. The new type of dosimeter uses the luminescence emitted after a stimulus by an electric current or LED light, and may be used to monitor patients during X-ray exams, in nuclear medicine, or in radiotherapy for treating cancer. According to Tatumi, a dosimeter based on carbon-doped alpha-alumina is commercially available, but it is manufactured using a very costly crystal-growing process that requires high pressures and temperatures. “We chose to use more modern, efficient, and inexpensive processes,” she says. “They permit a simple, well-controlled doping process, both with regard to quantity and purity of the doping materials.” A patent for the project has been filed and is now pending at the Brazilian Industrial Property Institute (INPI). “The dosimeter is already complete and may become a commercial product,” says the researcher.