A project announced at the ICTR-PHE 2012 medical conference has seen the light of day at CERN: MEDICIS (Medical Isotopes Collected from ISOLDE) will produce radioactive isotopes for medical research with unused beams from ISOLDE. Such isotopes are used in medicine to highlight specific cells for imaging, or to target them for destruction.
"At ISOLDE we have the capability to produce a thousand different radioactive isotopes," says MEDICIS leader Thierry Stora, who also leads ISOLDE's Targets and Ion Sources Development Team. "MEDICIS will use the expertise and infrastructure of ISOLDE to produce isotopes that could be useful in medicine."
At the ISOLDE facility, physicists bombard various targets with beams of protons. Of the incident beams, only 10% are stopped by the targets to achieve their experimental objectives, while the remaining 90% are not used. Adding a second target for MEDICIS behind the first will allow a portion of these lost beams to be re-used, without interrupting ISOLDE's scheduled experimental programme.
Once the second target has been bombarded and the "medical" isotopes created, the sample will be transferred by means of a pneumatic transport system to a shielded cell, funded by the Knowledge Transfer Fund. When the sample reaches the cell an operator will extract and purify the isotopes, which will be sent in batches to external medical-research laboratories.
"CERN-MEDICIS will bring together cancer specialists, surgeons, experts in nuclear medicine, scientists and experts from ISOLDE," says Stora, "A real tiger team!" The project 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.
Making isotopes
ISOLDE experts can modify the structure of a material by bombarding it with proton beams. When the nuclei of the atoms in the target material break apart, new elements form along with their radioactive isotopes.
Nuclei can break apart in three ways: In fragmentation, a small piece breaks off the nucleus, leaving a lighter nucleus; in fission, a heavy nucleus is split into two nuclei of intermediate mass; and in spallation, protons or neutrons are ejected from the nucleus, leaving behind a nucleus closely related to the original.
Titanium, lead, ceramics and many other substances can be used as target material. By choosing just the right combination of target and method, ISOLDE physicists produce a wide range of made-to-order radioactive isotopes.