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Licensees are required to report certain medical events that meet the criteria defined in 10 CFR § 35.3045, Report and Notification of a Medical Event. Such reports allow the NRC to identify the causes of the events so as to prevent their recurrence and to notify other licensees so they can take action to prevent such events at their facilities. The NRC Staff and the Advisory Committee on the Medical Uses of Isotopes (ACMUI) perform annual reviews of medical event reports to identify trends, patterns, generic issues, and generic concerns, and to recognize any shortcomings related to specific equipment or procedures.

On August 26, the NRC issued Information Notice 2019-07, which documents the ACMUI’s most recent review. The NRC uses information notices to inform addressees of significant, recently identified operating experiences that involve safety, safeguards, or environmental issues. Addressees are expected to review the information for applicability to their operations, and to consider appropriate actions to avoid similar problems.

The ACMUI recently reviewed four years of medical event reports to identify any common causes, and recommended methods to prevent future medical events. The review determined that licensees reported 212 medical events in those four years. A breakdown of the events by regulatory use appears below.


Number of Medical Events

Imaging and Localization Using Unsealed Byproduct Material


Unsealed Byproduct Material with Written Directive Required


Manual Brachytherapy


Afterloader Brachytherapy


Gamma Stereotactic Surgery


Radioactive Seed Localization


Yttrium-90 Microsphere Brachytherapy


In reviewing the events, the ACMUI identified the following common causes:

  • Unsealed Byproduct Material with Written Directive Required: Several events involved the administration of the wrong drug and/or dosage, or the administration of the drug to the wrong patient.
  • Manual Brachytherapy: Several events involved a different implanted source strength than that prescribed in the written directive.
  • Afterloader Brachytherapy: Several events involved use of the wrong treatment plan, the use of the wrong reference length, or the recording of the wrong dose or source strength.
  • Gamma Stereotactic Surgery: Several events involved patient setup errors and the wrong location of treatment selected on the treatment plan.
  • Yttrium-90 Microsphere Brachytherapy: Several events involved the administration of a dosage that differed from that stated in the written directive, while others involved the selection of the wrong catheter placement.

In an effort to prevent recurrence of such events, the ACMUI recommended that licensees take time out to identify the patient using two identifiers (e.g., name and date of birth) and to confirm the procedure to be performed, the isotope to be used, the dose, and the anatomic location to receive treatment. The ACMUI also recommended that licensees consider the following types of refresher training: (1) taking a review course from a professional society; (2) reading review articles; (3) speaking to colleagues with more experience with the procedure; (4) performing a dry run of the procedure with the team; and (5) reviewing the mechanics of the device setup and its operation.

The NRC staff further recommended that licensees provide adequate training to medical staff following the introduction of new equipment or software, or updates to existing software.

We will continue to monitor issues related to the medical uses of isotopes.