Ongoing problems with access to technetium-99m have led to the postponementof nonurgent scans, reintroductionof procedures that had beenphased out, and off-label use of otherradiopharmaceuticals.
Ongoing problems with access to technetium- 99m have led to the postponement of nonurgent scans, reintroduction of procedures that had been phased out, and off-label use of other radiopharmaceuticals.
Tc-99m is used in 70% to 80% of all nuclear medicine procedures, and demand is growing. It is produced naturally during the decay of the radioisotope molybdenum-99, which itself is generated as a byproduct of uranium fission.
All three European nuclear reactors that generate Mo-99 were shut during September. The Osiris reactor in Saclay, France, and the BR-2 reactor in Mol, Belgium, were closed for scheduled maintenance, and the High Flux Reactor at Petten, the Netherlands, was shut after a routine inspection revealed escaping gas bubbles in its cooling system. It was not due to restart Mo-99 production until late October at the earliest.
To make matters worse, one of the two sites in Europe that refines Mo-99 and distributes Tc-99m generators to hospitals and clinics was closed as well. The shutdown of the Institut des Radioéléments in Fleurus, Belgium, followed a 40-GBq leak of iodine-131 through the plant’s chimney. The IRE administration hoped to resume isotope delivery by the beginning of October, but this decision was in the hands of Belgium’s Agency for Nuclear Control.
Nuclear medicine physicians at the Manchester Royal Infirmary in the U.K. have had to work with 30% of their usual Tc-99m supply. This should be sufficient to cover urgent clinical cases, according to Dr. Robert Shields, manager of the hospital’s nuclear medicine department. Some nonurgent tests have been rescheduled, and, where possible, myocardial perfusion imaging has been performed with thallium-201.
"Tl-201 can give perfectly acceptable results for these heart scans. It takes a little longer, and the procedure is different, so we have had to train our staff to do these studies. But by making this switch, we are able to preserve our capacity for about 70% of our work," he said.
The situation at Antwerp University Hospital (UZA) was stable but deteriorating, according to Dr. Laurens Carp, a nuclear medicine physician at UZA and secretary general of the Belgian Society for Nuclear Medicine. The available Tc-99m has had to be prioritized. Doctors may also try harvesting Tc-99m twice a day from their Mo-99 source instead of just once.
No imaging appointments had yet been canceled at the University Hospital Copenhagen, despite a 50% drop in isotope supply levels over the summer, said Prof. Liselotte Højgaard, director of clinical physiology, nuclear medicine, and PET.
The need for Tc-99m was being assessed on a case-by-case basis. Fluorine-18 sodium fluoride PET was replacing bone scintigraphy, I-123 had been ordered for thyroid scans, and Tl- 201 had been reintroduced for myocardial scintigraphy.
"I have been in this area for about 25 years, and I have never experienced anything like it," Højgaard said. "As doctors, it is very important that we adopt a proactive approach and do the very best for our patients, instead of sitting back and saying, ‘I have to cancel.’"
Large university hospitals with cyclotron facilities that can make alternative radioisotopes may be in a better position to ride out the shortage than smaller clinics, said Prof. Wolfram Knapp, president-elect of the European Association of Nuclear Medicine and director of the nuclear medicine clinic at Hanover Medical School in Germany.
The EANM advised all institutions seeking to substitute Tc-99m with a product that does not have marketing authorization to clarify their position with the appropriate regulatory authorities.
Although the supply of Tc-99m has previously been good in Europe, radioisotope manufacturers should consider liaising more closely in the future to avoid similar problems, said Prof. Alan Perkins, a professor of medical physics at the University of Nottingham, U.K., and honorary secretary of the British Nuclear Medicine Society.
"Out of this I think will come more international cooperation and agreement about how the reactors are operated," he said.
-By Paula Gould