The Michelin Chefs of Radionuclides!

How difficult to extract radionuclides are produced at CERN-MEDICIS

By Amedeo Habsburg

Did you know that 80% of restaurants fail within their first 5 years of operation? Well, the worlds of radionuclideproduction and restauration are both full of high pressure, hot spaces, and little margin for failure. This being said, with talent and a little luck, late last year CERN-MEDICIS celebrated its 7th year of cooking up highly challenging, yet important radionuclides. Over the years, some of its key, yet most difficult-to-extract dishes have been; Scandium (43/44/47), Terbium (149/152/155), Actinium (225), Barium (128), and Erbium (169). All these radionuclides have a high impact for diagnostics or Targeted Radionuclide Therapy (TRT), however demand highly complex production methods, much like the complex dishes of the world’s most prestigious Michelin Star chefs.

At the base of MEDICIS’ production, lies a basic recipe; mix the ingredients, cook at high temperatures (~2000°C), and serve. A basic recipe, yet its execution distinguishes the amateurs from the Michelin Stars.
The MEDICIS team first starts by irradiating a target material. They work with a pantry of different targets, from Titanium to Thorium, in order to tailor the radionuclide outcome. Specialists in the team even create their own targets, instead of procuring, for further control of irradiation outcomes.

Fun fact: To reduce costs at the beginning of ISOLDE, a common cooking pot was used as a vacuum vessel for irradiation (as seen in the photo above; first target from the left).

Once irradiated the target is heated to temperatures around and sometimes above 2000°C, in order to diffuse and effuse the isotopes to the ion source. Temperatures are precisely controlled to extract the necessary isotopes while leaving impurities behind. The amount of nuclides collected will heavily depend on the temperature the team decides to use. On top of this, the high temperatures and refractive nature of elements such as Scandium, Terbium, and Actinium make them difficult to extract. MEDICIS has, however, managed to extract the highest grade purities of these elements in the world.

Following heating, the radionuclides are ionised through surface ionisation, electron impact, and laser ionisation. Here the chefs use a variety of different wavelengths as tools to ionise specific elements. Subsequently, the produced ionized radionuclides go through MEDICIS’ mass separation which allows the team to select and extract specific masses of ions. The combination of these technologies allows purities that no other facility can recreate.

In addition, much like the best chefs, the MEDICIS team refine their process and recipes to consistently advance. By allocating time to developments, MEDICIS improves on the achievable yields and effectiveness via PhD, Masters, and summer student projects to make even “grander” dishes, that could suit more customers.

Finally, the radionuclides are ready to serve. Sadly, however, no piece of fancy china awaits them. They are impregnated on small salt foils, which can be correctly packaged and sent to research hospitals around the world.

As seen, the production of medical radionuclides may slightly mirror the culinary arts and certainly deserve their first Michelin Star, however, we must remember that they hold an importance much greater than filling our stomachs. They exist to one day allow revolutionary cancer treatments, giving hope to people who need it most.