Following a public teleconference of the U.S. Nuclear Regulatory Commission’s (NRC) Advisory Committee on Medical Uses of Isotopes (ACMUI) convened last month by the NRC, its ACMUI Subcommittee on Extravasations and Medical Event Reporting has released a preliminary report. The report provides the subcommittee's evaluations and recommendations in response to a draft report by the NRC staff on whether extravasations during nuclear medicine procedures merit a change in medical event reporting to the commission. (Extravasations are tissue infiltration resulting from the inadvertent injection of a radiopharmaceutical into the tissue instead of the intended vein.) We discussed this activity in a Viewpoints article last month.

The process for considering regulatory oversight of extravasations began last year when the NRC requested public comments on a petition that the NRC revise its current policy that exempts extravasations from medical event reporting. Until that point in time, it had been the consensus of medical societies, and leading members of the nuclear medicine and radiology communities that generally there was no clinical data that diagnostic radiopharmaceutical extravasation was a patient safety issue. 

The NRC staff's preliminary evaluation provided a number of rulemaking options, ranging from taking no action to implementing one of several different options requiring that certain extravasations be reported as medical events. The various options would add varying regulatory burdens on licensees (and regulators). In evaluating the regulatory options, the subcommittee examined the following considerations:

• Medical event reporting, when appropriate, is an effective regulatory tool for NRC to collect information on adverse consequences of using radioactive material in medicine.

• Data about the frequency, severity and causes of radiation injury are necessary to support NRC’s radiation safety mission.

• Complexities and uncertainties in radiation dosimetry make it difficult to provide precise estimates of radiation doses to small tissue volumes near injection sites.

• Some radiopharmaceuticals do not have radiation emissions that can be easily imaged by nuclear medicine gamma cameras.

• Numerous clinical trials are underway for novel therapeutic radiopharmaceuticals. Potential consequences of extravasating therapeutic material, particularly alpha-emitting radiopharmaceuticals, may warrant a framework for regulatory oversight.

The subcommittee ultimately voted to recommend an option to NRC that requires reporting to the NRC whenever extravasation events require medical attention. The subcommittee believes that taking this step would provide NRC with information on the types of radiation injuries caused by extravasation, and the frequency of such injuries. Generally, the subcommittee believes that there is no clinical evidence that patients are being harmed, either from excess radiation dose or from compromised diagnostic studies because of radiopharmaceutical extravasation. And it noted that monitoring for extravasation will not prevent those events from occurring.

Ultimately, the subcommittee concluded reporting extravasations would lead to the establishment of appropriate medical event criteria to capture those extravasation events that could result in patient harm so that they could be further evaluated. The subcommittee also hopes that medical institutions will adopt quality assurance policies to monitor and improve the extravasation rates as part of their medical quality improvement programs, even though they would not be subject to regulation by the NRC.