CERN to start producing medical isotopes

A promising project that was hailed at the ICTR-PHE 2012 medical conference (see Bulletin issues 10-11/2012 and 12-13/2012) has seen the light of day at CERN. The project, known by the name of MEDICIS, will make it possible to produce a large variety of radioactive isotopes for medical research.


This image of a brain, superimposed on a drawing by Leonardo da Vinci, was taken by a PET scanner after injecting a molecule containing a positron-emitting isotope. CERN-MEDICIS will produce new isotopes for imaging which will be able to show up cancerous tissues and destroy them by emitting local radiation as the isotopes decay.

In the United States, a new radium-based drug which targets bone metastases is about to go on the market. Radium, which can be brought to bear at the cell level, is a potent weapon in the fight against certain types of cancer, and is opening the way to a new form of medicine. This is the direction that CERN has decided to follow through the CERN-MEDICIS* (Medical Isotopes Collected from ISOLDE) project.

Thierry Stora, leader of the CERN-MEDICIS project and of the Targets and Ion Sources Development Team at ISOLDE, explains: "At ISOLDE we have the capability to produce a thousand different radioactive isotopes. The objective of MEDICIS is to make use of the expertise and infrastructure of ISOLDE to produce radioactive isotopes that could be useful in medicine."

In ISOLDE, targets are bombarded with proton beams. Of the incident beams, only 10% are actually stopped in the targets and achieve their objective, while the remaining 90% are not used. By putting up a second target for MEDICIS behind the first one, a portion of the lost beams could be re-used. This will allow us to produce isotopes specially for medicine, without interfering with ISOLDE’s work,” underlines Thierry Stora. Once the second target has been bombarded and the “medical" isotopes created, the sample will be transferred to a shielded cell in the ISOLDE laboratory, by means of a pneumatic transport system. The transport system and the shielded cell will be funded from the Knowledge Transfer Fund” (see the article in Bulletin 04-05/2012), says a contented Thierry Stora.

When the sample reaches the shielded cell, an operator will start the process of extracting the radioactive isotopes. The highly purified isotopes will be formed into batches that can be sent to external laboratories that will use them for medical research. “CERN-MEDICIS is supported by the Hôpitaux Universitaires de Genève, the Centre Hospitalier Universitaire Vaudois (CHUV) in Lausanne and the cancer research institute ISREC of the École Polytechnique Fédérale de Lausanne. It will bring together cancer specialists, surgeons, experts in nuclear medicine, scientists and experts from ISOLDE: a real tiger team!” says an enthusiastic Stora.

In the future, MEDICIS is expected to join other European institutes specialising in the production of radioactive isotopes for medical research.

* Note that the name “MEDICIS” has not yet been approved and may change.

Producing isotopes

By bombarding a specific material with a proton beam, the experts from ISOLDE can modify its structure. When the nuclei of the atoms in the target material are broken apart, new elements are created—including radioactive isotopes.

There are three possibilities for breaking apart a nucleus. Fragmentation involves a small piece being broken off the nucleus, leaving a lighter nucleus. In fission, a heavy nucleus is split into two nuclei of intermediate mass. In spallation, finally, protons or neutrons are ejected, leaving behind a nucleus that is closely related to the original.

The target material can be of many different substances: titanium, lead, ceramic, etc. By choosing just the right target and method, ISOLDE can produce a wide range of different radioactive isotopes.


by Anaïs Schaeffer