In 2017, a 69-year-old man with pancreatic cancer went to hospital with abnormally low blood pressure. Sadly, he died only two days later, and his remains were cremated.

What nobody at the hospital or the crematorium knew, was that this hadn't been the man's only recent trip to hospital.

Just one day earlier, in fact, he had been injected with a radioactive compound at another hospital to treat his tumour – and when his mortal remains were incinerated, this radioactive and potentially dangerous dose of lutetium Lu 177 dotatate was still inside his body.

This alarming case, reported in a new research letter this week, illustrates the collateral risks potentially posed by on average 18.6 million nuclear medicine procedures involving radiopharmaceuticals performed in the US every year.

While rules regulate how these drugs are administered to living patients, the picture can become less clear when those patients die, thanks to a patchwork of different laws and standards in each state – not to mention situations like the 69-year-old man, whose radioactive status simply slipped through the cracks.

"Radiopharmaceuticals present a unique and often overlooked postmortem safety challenge," researchers from the Mayo Clinic explain in a case note.

"Cremating an exposed patient volatilises the radiopharmaceutical, which can then be inhaled by workers (or released into the adjacent community) and result in greater exposure than from a living patient."

In this patient's case, once the treating physicians and the radiation safety department at the initial hospital became aware of the man's death, they got in touch with the crematorium.

Almost a month after the cremation took place, they used a Geiger counter to detect radiation levels inside the cremation chamber and on equipment, including the oven, vacuum filter, and bone crusher.

What they found were low but nonetheless elevated levels of radiation, while a spectroscopic personal radiation detector identified the primary radionuclide culprit – lutetium Lu 177, the same radioactive compound used to treat the man.

"This wasn't like the second-coming of Chernobyl or Fukushima, but it was higher than you would anticipate," case co-author and radiation safety officer Kevin Nelson told The Verge.

While there's no definitive proof specifically linking the patient's radiopharmaceutical dosage to the radiation levels detected in the crematorium, it's certainly the most likely explanation for how those trace levels of lutetium Lu 177 could be there.

It's also the first time radioactive contamination of crematory facilities has been documented like this.

But that's not the most concerning part of the story.

When the researchers analysed the crematorium operator's urine to see if the employee had also been contaminated by radiation exposure, they couldn't find any traces of lutetium Lu 177.

They did find something, though: a different radioactive isotope, called technetium Tc 99m. The worker said they had never been exposed to the compound as part of a nuclear medicine procedure.

Because of this, the researchers say it's plausible the operator could have been exposed to volatilised technetium Tc 99m while cremating other human remains – and if they're right, we could be looking at a broader issue here, as opposed to an isolated, unfortunate one-off.

Still, the amount of radiation we're talking about is very low, so even while the problem of accidental volatilisation could be widespread in the cremation industry, it may not actually be as dangerous as it sounds.

"I don't think this is an issue that may entail any risk of cancer or other radiation-induced illnesses," cancer researcher Paolo Boffetta from the Icahn School of Medicine at Mount Sinai told UPI.

"Having said that, it's clear it's a possible source of exposure, and if someone is exposed regularly, every week or every few days, then it may become a source of concern."

Given more than half of all Americans eventually get cremated, postmortem management of individuals who receive radioactive drugs is an area the US health system needs to work on, the researchers say.

This includes better ways of evaluating radioactivity in deceased patients (prior to them being cremated), and also standardising ways of notifying crematoriums about their clients.

After all, nobody really has any idea how often this is happening.

As nuclear scientist Marco Kaltofen from the Worcester Polytechnic Institute in Massachusetts, who wasn't involved with the research, told BuzzFeed News: "They only happened to catch this one case because normally they don't look."

The findings are reported in JAMA.