Fast determination of 90Sr in urine samples and internal dose evaluation in emergency situations

During nuclear or radiological emergency, it is important to rapidly identify contaminated people to administer them necessary treatments as soon as possible. A simple method to project and adapt measurement techniques for a mass monitoring of internal contamination based on the concept of "minimum detectable dose" has been developed. This method has been applied to ⁹⁰Sr, as it has a specific significance for spread in anthropic activity and radiotoxicity, so to require a fast, precise and suitable technique for its determination in many biological samples. A chromatographic separation allowed to isolate and measure by gas proportional counting ⁹⁰Sr excreted into urine and to calculate the correspondent intake and committed effective dose within half a day, taking also into account an overestimation of 10 % of total activity due to ⁹⁰Y not eliminated or formed during the measurement. The capacity to attribute values of committed effective dose lower than the precautionary reference level of 10 mSv, which is generally considered safe and does not typically cause health observable effects, has proved the method efficacy, even for a sample collection range larger than 20 days from the intake and for the most dangerous Type S of the investigated radionuclide.