An Arizona crematorium was polluted by a plume of radiation after operators inadvertently incinerated the remains of a cancer patient who had undergone radioactive treatment a few days before his death unexpected.
Doctors at the Mayo Clinic in Phoenix, who reported the contamination, were alarmed by the discovery that the crematorium operator also had traces of radioactive material in his urine, but from an isotope different from that found in the cancer patient recently cremated. Doctors released their results Tuesday in a JAMA letter of research.
While the radiation levels detected in the crematorium and its operator were unlikely to cause any damage, doctors say the problem requires more attention. They conclude:
Further studies are needed to assess the frequency and extent of radioactive contamination and the health effects of repeated or long-term exposure of crematorium employees in the United States, from both more than the cremation rate was over 50% in 2017.
They also note that there is no federal regulation regarding radioactive materials in crematoriums and that existing regulations vary from state to state. Arizona, for example, currently has no rules requiring doctors to inform crematoria of the presence of radiopharmaceuticals in recently deceased patients. Florida, meanwhile, forbids crematoriums to burn radioactive waste unless they obtain government approval.
Arizona doctors were informed of the problem after the unexpected death of a 69-year-old man struggling with a pancreatic tumor a few days after receiving nuclear medicine treatment. The doctors treated the man with 193.6 mCi of Lu lutetum 177 dotatate intravenously, whose half-life is about 6.65 days. The day after treatment, the man went to another hospital for low blood pressure. He died suddenly from an underlying illness two days later and was then cremated five days after his radioactive treatment.
The doctors who treated the man with the radiopharmaceutical did not immediately announce his death. When they discovered, they informed the crematorium, which then investigated a possible contamination. But at that time, it had been a month since the cancer patient had received his radiation treatment.
Investigators found contamination of Lu 177 lutetium on crematorium equipment, including the oven, bone crusher and vacuum filter, with a maximum exposure of 7.5 mR per hour in direct contact with the detector Geiger-Mueller. For practical reasons, this equates to a dosage equivalent to 0.0075 rem / hour. The maximum limit of a worker's body exposure is set at 5 rems per year of the US Occupational Safety and Health Administration, and the annual total exposure limit of the Nuclear Regulatory Commission for a member of the public is 0.1 rems a year.
When the investigators examined the crematorium's urine, they did not find Lu 177. But they found traces of technetium Tc 99m, which is a radioactive tracer (with a half-life of six hours). ) used in diagnostic tests. The operator had not had such tests, however.
Given the short half-lives of the two isotopes, Mayo Clinic physicians do not believe that accidental cremations have pushed advertising beyond the NRC public boundary. But, they say, the case highlights "a unique and often overlooked challenge to post-mortem safety".
JAMA, 2018. DOI: 10.1001 / jama.2018.21673 (About the DOIs).