Production of non-conventional high specific activity radionuclides for biomedical, toxicological, and environmental purposes

Low- and medium-energy accelerators and sometimes thermal nuclear reactor, allow production of very high specific activity radionuclides (HSARNs) for biomedical, environmental, toxicological and occupational investigations. Specific Activities of the order of GBq·μg-1 are achieved; this means that the experiments can be carried out in the sub-nanogram range (nanochemistry). The HSARNs allow labeling increasing amounts of different chemical forms of toxicological or pharmacological interest, with the possibility to obtain dose vs. effect relationships on both cell cultures and laboratory animals. In nuclear medicine, “very high” AS - in No Carrier Added radiopharmaceuticals - are normally required to avoid undesirable effects due to high chemical concentration of labeled species. Some labeled species are sparingly soluble in body fluids, organs and barrier membranes; some others present toxic or adverse effects onto humans; a low AS(NCA) means a high molar concentration and could interfere into normal human metabolism, by inducing undesired pharmacological effects. High-resolution HPGe c-spectrometry and b-spectrometry by liquid scintillation counting allow determination of radionuclidic and radiochemical purities of the tracer and determination of radiochemical yield of processing procedures. Chemical purity determination is carried out by a range of analytical and radioanalytical techniques. Radionuclide production for biomedical applications has been brought up in the years, at LASA, particularly in co-operation with JRC-Ispra of EC and LENA-Pavia