“I remember in Geneva two months ago we said, ‘Pay attention, because in this specific week there is a risk of shortages if there is a problem with one of the active reactors,’ and that’s what happened,” David Crunelle recalls. , spokesperson for Nuclear Medicine Europe (NMEU), an industry association.
Due to their very nature, it is impossible to store these radioactive substances: they are fleeting. Technetium-99m functions as a radioactive tracer because, when it decays, it emits gamma rays with a photon energy of 140 KeV. This is “pretty ideal” for detection using a gamma-ray camera, says Cathy Cutler, chair of isotope research and production at Brookhaven National Laboratory in the United States.
But technetium-99m has a very short half-life, only approximately six hours. Hence, radioisotope production facilities send miniature generators containing molybdenum-99 to hospitals. These generators, sometimes called “molybdenum cows,” produce the desired technetium-99m as the molybdenum-99 decays, a bit like a portable technetium-99m vending machine, which runs out after about two weeks, a once the molybdenum-99 has been completely used up. deteriorated.
Glenn Flux, head of radioisotope physics at the Royal Marsden Hospital and the Institute of Cancer Research in London, says what differentiates a technetium-99m scan from, say, a CT scan or MRI, is that it reveals how patients’ organs or a tumor function. They are working, for example, by revealing blood flow to the area in question.
“The CT scan will show you if there is a tumor, but the technetium or other isotopes will tell you if it is active or aggressive,” explains Flux.
The recent shortage of radioisotopes has led to the cancellation of a few thousand appointments in the UK alone, estimates Stephen Harden, vice-president of clinical radiology at the Royal College of Radiologists (RCR). Healthcare staff sprang into action to distribute the remaining radioisotope supplies across the UK, to ensure that the most urgent patients (those with cancer, for example) could still attend their scans. “If there had not been a coordinated policy at the national level, there would be significant regions of the country without any supply,” Harden says.
Crunelle and his NMEU colleagues continually monitor the production of medical radioisotopes at key reactors around the world. They find out about maintenance schedules well in advance, and as such, NMEU often advises reactor bosses to push these dates back slightly, for example, to help minimize the risk of multiple shutdowns occurring at the same time. NMEU staff use software, a type of reactor maintenance calendar, that allows them to forecast production levels. But sometimes unpredictable events happen, like the pipeline problem in Petten.