Optimization of the production of non-conventional high specific activity radionuclides for medicine, toxicology and nanotoxicology

The use of radionuclides plays a crucial role in Life Science: this use is applied in nuclear medicine in the areas of diagnostics, of metabolic radiotherapy and of the recent discipline that goes by the name of theranostics, in environmental studies related to prolonged exposure to contaminants with extremely low concentrations, as well as nanotoxicology. With regard to the Nuclear Medicine, the possibility of radiolabeling pharmaceuticals, monoclonal antibodies or fragments of peptides which are specific for receptors of tumor cells or of the corresponding antigens, it is an extremely interesting strategy to treat these diseases; at the same time the labeled compounds, specific to the "target" to be treated, must be very selective in order to minimize the dose to healthy tissue surrounding the diseased area. It is therefore necessary to employ non-conventional radionuclides suitable for diagnostic techniques like Positron Emission Tomography (PET) or Single Photon Emission Tomography (SPECT), for metabolic radiotherapy and for theranostics. The selection of such radionuclides should be conducted according to criteria and parameters that involve the physical characteristics linked to the different modes of interaction of the ionizing radiation as a function of the type of emission and the half-life of the radionuclide, as well as radiation protection aspects related to the safety of operators in the preparation and in the manipulation of the labeled compound, the possible exposure of people who take care for the patient and the reduction of the amount of radioactive waste that are going to have an environmental impact. For the production of each non-conventional radionuclide it is necessary to point out a protocol that provides the optimization of production with high specific activity of the radionuclide of interest, typically through the use of charged particle accelerators, the development of appropriate radiochemical separations and of a strict quality control system of the product obtained. After presenting these basic concepts and describing the Laboratories of the Physics Department that are installed at the LASA lab in Segrate, equipped with the required features and permissions for conducting such researches, we will present the latest results related to the production of new radionuclides and the possible use of radiolabelled nanoparticles.