PET Scan Radiation Warning Issued By FDA

U.S. medical regulators are warning that positron emission tomography (PET) scans using the CardioGen-82 radionuclide generator could lead to excessive radiation exposure. 

The FDA issued a drug safety communication on July 15, warning that some patients have suffered increased radiation from PET scans and announced that the agency is currently investigating the cause of the radiation exposure overdoses.

The warning was issued after the FDA received at least two reports of radiation overexposure from patients scanned with the CardioGen-82, which is manufactured by Bracco Diagnostics, Inc. In both cases, the patients received an injection of rubidium (Rb)-82 chloride, which is a standard part of receiving a PET scan. The FDA suspects the excess radiation came from strontium isotopes that were accidentally injected by the CardioGen-82 with the Rb-82 injection.

PET scans use radioactive drugs to create an image of the heart. Rb-82 is an isotope created using Strontium, but a correct injection only injects Rb-82 isotopes into the patient, which have a half-life of just 75 seconds. In the case of the two incidents reported to the FDA, the patients were injected with strontium-82 as well, which has a half-life of 25 days.

The FDA indicates that the dangers from the exposure are minimal, but warns that any excessive radiation exposure is cause for concern. The agency believes it would take much more radiation than the two patients received to represent a threat of severe health effect.

The agency is recommending that healthcare professionals closely adhere to quality control measures and required testing to detect what is being called a “strontium breakthrough” from the CardioGen-82. The FDA also recommends healthcare professionals look at alternative heart scan techniques while federal investigators look into the problem.

The FDA suggested patients scheduled to receive a PET scan using a CardioGen-82 consider delaying their scan until the FDA concludes its investigation.