Chewing gum for retrospective determinations of radiation doses, by means of EPR analysis

摘要

In case of an accident or attack involving radiation there is need for fast and accurate estimations of absorbed dose to individuals to optimize the medical treatment or in case of moderate doses to estimate the risk of late effects. Ionizing radiation induces free radicals which are rather stable especially in crystalline materials. By means of EPR (Electron Paramagnetic Resonance) spectroscopy the number of free radicals can be measured, which is proportional to the absorbed dose in the material. EPR-dosimetry on tooth enamel is today one of the best method as a rather fast method for dose reconstructions. Till now a drawback is that accurate analysis must be done at extracted teeth. In the pockets of individuals some materials like sweets, medicines and chewing gum has a content of sugar or sweetening which can be used for EPR-dosimetry. After a brief testing sucrose and sugar free chewing gums were chosen and the specific aim was to analyze the EPR spectra, establish a dose response curve and estimate the accuracy for dose reconstructions. Samples of 300 mg of sucrose were put into test tubes and irradiated with doses from 0 to 21 Gy and 10 chewing gums were irradiated from 1 to 10 Gy. A regression curve was obtained for both measurements and the accuracy of the dose reconstruction was checked in a blind test with irradiation of a chewing gum. A dose of 4,24+-0,35Gy (1SD) was estimated for the blind dose, which true value was 3,96 Gy. Further investigations are believed to improve the accuracy significantly.