Radioactive isotopes produced for medical applications: setting up an accurate measurement method for production cross section

National audienceThe nuclear medicine is a medical specialty that uses radionuclides for diagnosis or therapy. Several modalities are used in diagnosis (PET/SPECT, Positron Emission Tomography/Single Photon Emission Computed Tomography) which takes advantage of the photon emissions occurring during the decay of the radionuclide. In therapy, strongly interacting particles obtained through the radioactive decay are used such as alpha, beta or Auger electrons. They are mostly used coupled to a vector molecule for targeted therapy. The trend followed by nuclear medicine is to become more and more personalized to each patient. To reach that goal, a wide variety of radionuclides (different decay particles, different half-lives, different chemical properties) must be available to meet the patient’s need. Their production is achieved using reactor or accelerator and has to be well controlled. In order to optimize the production of radionuclides, a good knowledge of the radionuclide production cross section is required. In collaboration with the GIP ARRONAX[1] which possesses a multi-particle high energy cyclotron, the project is to get an accurate measurement of production cross sections for a wide variety of radionuclides. Among the information requires for a precise measurement, the flux of the incident particle is the more important one. The data about the particle flux of the beam can be evaluated using a monitor reaction with a well-known cross section whose values are recommended by the International Atomic Energy Agency (IAEA). The uncertainty (around 10%) associated to the monitor cross section values results in a high uncertainty on the measured ones. Another method is to measure the amount of charges crossing the stack. This method allows reducing the uncertainty on the measured cross section (