Nuclear medicine gains traction from PET/CT, new radioisotopes

Rapid technological developments, in terms of both instrumentation and radiopharmaceuticals, are making nuclear medicine an increasingly relevant part of daily clinical practice, according to Prof. Peter Ell, director of the Institute of Nuclear Medicine at University College London.

"Nuclear medicine is well, it is alive, it is progressing, and it is fascinating," he said in an invited lecture at the opening ceremony for a new radiopharmaceutical production plant in Belgium. "It continues to make an impact in healthcare."

The new BetaPlus Pharma site, opened officially in May 2007, is a joint venture between IBA and the medical universities of Saint-Luc, Brussels. Such a partnership between industry and academia is a great development for nuclear medicine, Ell said.

Ell used his lecture to emphasize the major contribution that nuclear medicine is making to early diagnosis, patient risk stratification, and treatment monitoring. Nuclear medicine techniques are helping to deliver comprehensive medical, diagnostic, and therapeutic services to hundreds of thousands of patients worldwide each year. Picomolar sensitivity means that a large variety of biologically relevant signals can now be imaged.

Specially designed radioligands are the key to comprehensive investigations of organ function and metabolism. Typical examples include perfusion studies of the heart and brain, and glucose metabolism in most cancers. Radiopharmaceuticals described as "special therapeutic bullets" are being used to treat pathology of the thyroid, cancers, lymphomas, and neuroendocrine tumors.

The availability of PET/CT technology is advancing studies of coronary artery disease and neuroendocrine pathology as well as the monitoring of advanced transplant protocols in lymphoma patients, Ell said. Myocardial perfusion studies combining perfusion data with coronary anatomy have now been performed in Europe, thanks to PET/CT. Ultrarapid myocardial perfusion studies of the heart have also been carried out with SPECT.

PET/CT with the radioisotope rubidium-82 makes it possible to reduce the total examination time from six hours to 30 minutes. This makes the procedure much more patient-friendly. The sensitivity of interpretation means that good data can be derived from relatively simple techniques.

"When you use Rb for cardiac PET, it is often said that a 64-slice CT scanner is necessary. But if you use the data well from a 16-slice CT system, you get good information," he said.

The emerging role of receptor imaging in oncology confirms that there is life after FDG, Ell said. New detectors are now in commercial development. These promise to improve resolution and sensitivity, and speed up the time for data acquisition.

"If this development pans out, it could be a very important improvement," he said.

Ell also expanded on the role of PET/CT in the management of lymphoma patients subject to transplantation. Studies have shown that it is possible to predict the likelihood of relapse after radioisotope therapy. Nuclear medicine physicians need to pursue collaborations with biologists and other scientists to refine decisions over which paths to pursue.

"Nuclear medicine in general hasn't been very good at choosing which signals to follow," he said.