RADIONUCLIDES FOR MEDICINE - EXCITATION FUNCTIONS FOR THE PRODUCTION OF TC-99M, ZR-89 AND PD-103

The production of radionuclides for medicine is one of the most important directions of nuclear chemistry and nuclear industry. Radionuclides are used both for medical diagnostics of various diseases as well as for internal radiotherapy: the consumption of pharmaceuticals based on radioactive isotopes is growing fast. The main amount of commercial medical radionuclides is produced on nuclear reactors but more and more radiopharmaceuticals are produced on the base of accelerator produced isotopes. Even if the accelerator production is more expensive, it can provide a wider range of radionuclides and often provide higher specific activity. This work is focused on the production optimization of three main radionuclides Tc-99m, Zr-89 and Pd-103 irradiating, correspondingly, targets of enriched molybdenum-100, natural yttrium-89 and natural rhodium-103 with proton or deuteron beams accelerated by cyclotrons. Formation of several by-products synthesized in the same targets is also investigated because it is important to understand the presence of all the possible impurities to be removed with the radiochemical procedures. All these radionuclides are important and used in nuclear medicine. Tc-99m is considered the “workhorse” of radiopharmaceutical imaging and it is usually obtained from another radioactive parent isotope Mo-99 produced mostly in the world on nuclear reactors. However, in the last years, the direct production of Tc-99m from the Mo-100-enriched targets in low-energy proton accelerators – nuclear reaction (p, 2n) – is considered as possible substitution of reactor production and has good prospects for local needs. Zr-89 is a radionuclide extremely prospective for labelling monoclonal antibodies, bio-distribution studies, and immuno-positron emission tomography (PET) imaging. Pd-103 is used in brachytherapy and, with the rapid development of nanoscience and nanotechnology, it becomes appealing to make injectable nano-scale brachytherapy seeds. The production of Zr-89 and Pd-103 by protons was well studied and considered. In contrast, there are few experimental data on the excitation functions of the deuteron-induced nuclear reactions or these are rather scattered: the (d,2n) reaction appears to be very attractive and it deserves particular interest of study.