Day 1

Monday, July 1

• Visit of the ARRONAX cyclotron
• Lectures on radio-isotope production and extraction, radiochemistry and dosimetry
• 1 spot on nuclear medicine

• Radionuclide production: means and limitations
  Férid Haddad
  Researcher in Nuclear Physics on Production of Radionuclides for Medical Applications, Subatech
  Head of GIP ARRONAX

Radionuclides utilized in nuclear medicine are mostly produced artificially by induced nuclear reaction on a target material using different types of projectiles. To produce these projectiles one can use research nuclear reactors for neutrons or accelerators for protons, deuterons, ions, α particles, γ, etc. After the presentation of the overall radionuclide production scheme, we will describe the different production methods using the production of alpha emitters as a guide to enlighten their strengths and limitations.

• Radiolabelling Chemistry
  François Guérard
  Researcher in Medicinal Chemistry, Nuclear Chemistry and Radiochemistry, Nuclear Oncology group, CRCI²NA

The production of radiopharmaceuticals necessitates in most case chemical steps to bind the radionuclide to a disease targeting vector. The strategy employed depends on the chemical nature of the radionuclide, its physical properties and on the carrier molecule. In this session, the main concepts on which the chemists rely for the development of radiopharmaceutical will be introduced, with a particular emphasis on:

• the complexation of radiometals and the main rules for the design of a good radiochelate
• the radiolabelling with nonmetal radioisotopes and the main parameters to take into consideration to reach optimal labelling yields
• the main bioconjugation strategies, their strengths and weaknesses.

This presentation will provide the main keys to understand the challenges faced by the chemists and radiochemists in the development of radiopharmaceuticals.

• Internal dosimetry: from theory to practice
  Arnaud Dieudonné
  Medical Physicist in Nuclear Medicine, Centre Henri Becquerel, Rouen

While the concept of internal dosimetry dates back several decades, its routine clinical application is relatively recent and has been stimulated by the development of nuclear medicine imaging and new applications of targeted radionuclide therapy (TRT). One TRT modality that has particularly benefited from dosimetry over the last decade is liver radioembolization with Y90-loaded microspheres. New methodological concepts have been developed to better personalize dosimetry and plan treatment. Radiobiological concepts already applied to external beam radiotherapy (EBRT) can now be applied to TRT. This is not only interesting in terms of reconciling the clinical results of the two therapeutic modalities, but can also bring new perspectives to better control treatment outcomes. This conference will provide an overview of internal dosimetry and state-of-the-art protocols for beta emitters

• Targeted alpha therapy dosimetry
  Nicolas Chouin
  Researcher in Medical Physics, Nuclear Oncology group, CRCI²NA - Oniris Nantes

The history of targeted alpha therapy (TAT) is a very good illustration of the value of dosimetry in nuclear medicine. This therapeutic modality was indeed abandoned short after its debuts due to excessive toxicity observed on patients. Since then, it was progressively re-adopted in nuclear medicine while the right dosing (absorbed dose?) was approached. This is still an ongoing process. Whereas some normal-tissue dose limits for radionuclide therapy have been published lately, these values exclusively concern beta-emitters radionuclide therapy. This lack of knowledge is due to the limited data available on patients for TAT but it also reflects the difficulties related to alpha-particle dosimetry.

This lecture will provide an overview of the different specificities and challenges associated to targeted alpha therapy dosimetry:

• Low injected activity
• Alpha emitters decay chain
• Short range of alphaparticles

It will also describe the solutions provided in the recent years, the approaches envisaged in the future, and the preliminary dosimetric results from the ongoing clinical trials.

• Dosimetry in targeted radiation therapy: necessary, nice to have, or counterproductive ?

• Back to ISI NucMed program 2024