RESEARCH IN RADIOACTIVE DRUGS

NUCLEAR TRACERS: At Denmark’s National Research Centre Risø radioactive isotopes are created for use in scanning for cancer. Research is also conducted into new radioactive tracers which home on cancer cells by themselves and destroy them

Danish hospitals are enjoying a minor boom in the numbers of combined PET and CT scanners, which primarily are used for the diagnosis of cancer. After injecting radioactive tracers into the patient, the scanning process locates cancer tumours. Using 3D X-ray images, doctors can precisely visualise the anatomical details of tumours as well as seeing how widespread the cancer is, and whether there are metastases.

The increased number of scanners has led to a rise in the need for radioactive tracers. This has led to the establishment of a new laboratory at Denmark’s National Research Centre Risø, which conducts research into the development of new radioactive drugs as well as producing radioactive tracers for diagnostics and treatment.

Cyclotron
Risø previously had Denmark’s only nuclear reactors, which were used for research.

But following a political decision in Denmark many years ago not to build nuclear power plants for energy production, the nuclear research at Risø was gradually marginalised and the three test reactors were shut down. But at almost the same time as the last reactor was shut down, Risø bought a cyclotron for the production of radioactive isotopes.

“But we focus just as much on research and development into new biomedical tracers,” says programme manager Lars Martiny, who heads the Hevesy Laboratory at Risø’s department for Radiation Research. “The fact that we are also supplying hospitals is because the need is strongly increasing, but it also provides an important production routine for our research scientists.”

Destroys cancer cells
The Hevesy Laboratory, named after the Hungarian Nobel Prize winner for chemistry in 1943, who discovered how to use radioactive tracers to study biological processes, specialises in binding tracers to molecules with the main focus on the tracer F18-FDG, where a radioactive isotope of fluorine (F18) is bound to modified glucose. Cancer tumours consume glucose voraciously, and so they absorb more of the tracer than the surrounding tissue. The tumours thus appear very clearly on the PET scan.

“F18-FDG is today so established and well documented that it has become a common clinical aid,” says Lars Martiny. “Consequently we conduct research with other substances and molecules which can be helpful for both diagnosis and possible treatment, not just of cancer, but also other diseases. For instance, we are developing a special drug for the treatment of certain types of cancer. The substance, Y90-DOTATOC, contains a radioisotope of Yttrium and is special in the way that it tracks down certain types of cancer cells where it works directly by destroying the cancer cells with ionizing radiation.”

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