DEUTERONS EXPERIMENT - CSN 5--INFN, RESPONSIBLE: Mauro Bonardi
Deuteron beams can
in "selected cases" lead to the production of radionuclides "neutron
rich", which are often obtained in thermal nuclear reactor and used as
radiotracers (i.e. radiopharmaceuticals) in metabolic radiotherapy,
theragnostics. Several of these radionuclides have the same gamma
emitters (or negatron/positron emitters) and can therefore be detected
outside the body of the patient using imaging techniques such as
gamma-camera, SPECT or PET. The combination of metabolic radiotherapy
and imaging is nowadays named "theragnostic". Its importance lies in
the possibility for the nuclear medicine physician to check the
"effective" biodistribution of the radiotracer after administration to
the patient and the follow-up of the patient in case of repeated
The use of deuterons leads to a further series of considerable advantages, in addition to the increasing difficulty to have nuclear reactors for research. One of the most importatnt advantage is the possibility to obtain radionuclides with "high specific activity" in no-carrier-added (NCA) form. This as a consequence of the possibility with specific and selective radiochemical methods - in strictly NCA form - to separate the reaction products from the irradiated target and any radionuclide impurities not isotopic.
The radionuclides produced in NCA form with specific activity extremely high can be used in the biomedical sector, in particular in the metabolic receptorial radiotherapy.
Another technical advantage is that deuterons have a greater stopping power with respect to protons, allowing the use of targets with less thickness: this leads decreasing the amount of irradiated material,as well as the volume of the reagents and of the amount of synthesis, thus increasing at the same time both specific activity and the chemical purity of the radioactive product.
A further advantage of deuterons is that often show cross sections higher than the protons ones in the region of "compound nucleus", especially for the high Coulomb barrier of the high Z targets.
For each radionuclide under investigation, the experimental thin tagets yields of the radionuclide of interest and of the impurities are measured. From these results will be measured and determined the thick target yield in order to determine the best energetic window and the optimized couple (E,DE) to obtain the radionuclide with high radionuclidic purity. It will be pointed out a specific radiochemical separation and the quality control tests for the experimental detemination of the radionuclidic, radiochemical and chemical purity.
Finally for each nuclear reaction considered cross sections will be calculated in Milano with the code EMPIRE-II of the NEA and with the TALYS code (possibly in cooperation with LNL). Of particular importance is the calculation of the cross section of the interfering side reactions, which can lead to non-radioisotopic radionuclide impurities, sometimes with a long half-life that are hardly manageable, not so much from the point of view of the dose to the patient, as from the point of view of the personnel dose and radioactive disposal.