The US Nuclear Regulatory Commission’s (NRC’s) revised regulations regarding the medical use of byproduct material became effective on January 14, 2019—six months after being published in final form, and nearly a decade after the proposed rulemaking. See Medical Use of Byproduct Material—Medical Event Definitions, Training and Experience, and Clarifying Amendments, 83 Fed. Reg. 33,046 (July 16, 2018). The revised regulations amend 10 CFR Parts 30, 32, and 35. The NRC also issued guidance to provide additional detail regarding the substance of the revised regulations and to assist licensees with compliance. See Guidance for the Final Rule, Medical Use of Byproduct Material—Medical Events, Definitions, Training and Experience, and Clarifying Amendments, 83 Fed. Reg. 33,759 (July 16, 2018). Among other things, the amendments change the requirements associated with

  • reporting medical events involving brachytherapy;
  • training and experience for individuals involved in licensed activities;
  • molybdenum contamination and failed technetium and rubidium generators; and
  • naming associate radiation safety officers.

The NRC’s rulemaking makes the following various changes to NRC regulations regarding the medical use of byproduct materials.

Medical Event (ME) Reporting and Notification: Current ME criteria for brachytherapy implants in 10 CFR Part 35 are based on the dose administered to the patient. NRC Staff concluded that dose-based criteria are problematic for permanent implant brachytherapy because the absorbed dose can be challenging to calculate. Consequently, the revised regulations establish ME criteria based on the total source strength administered (activity based) rather than the dose delivered (dose based). Activity-based criteria should allow MEs to be identified sooner and for corrective actions to be taken in a more timely manner. As part of this change, licensees are required to develop, implement, and maintain procedures reflecting the new ME criteria.

Training and Experience (T&E) Requirements: Part 35 currently provides three pathways for radiation safety officers (RSOs), authorized medical physicists (AMPs), authorized nuclear pharmacists (ANPs), and authorized users (AUs) to satisfy T&E requirements:

  • Certification by a specialty board using a process recognized by the NRC or an Agreement State (certification pathway)
  • Evaluation by a preceptor of the individual’s T&E (alternate pathway)
  • Approval based on an existing NRC or Agreement State license

Under the certification and alternate pathways, the individual must obtain a written attestation signed by a preceptor with the same authorization. The attestation must state that the individual completed the necessary T&E requirements and achieved a sufficient level of competency to function independently in the position for which authorization is sought. The rulemaking eliminates the attestation requirement for individuals using the certification pathway. For others, the attestation requirement still applies; however, residency program directors may now provide the attestation.

Molybdenum Contamination Measuring: A technetium-99m generator is a device used to extract the metastable isotope 99mTc from a source of decaying 99Mo. Most commercial 99Mo - 99mTc generators use column chromatography, in which 99Mo is adsorbed onto acid alumina (Al2O3). Pulling or pushing normal saline solution through the column of immobilized 99Mo elutes the soluble 99mTc, resulting in a saline solution containing radioactive 99mTc, 99Tc, 99Mo, and aluminum ions; the 99Mo and aluminum ions are contaminants, the quantities of which must be limited for the protection of the patient.

Prior to 2002, Part 35 required licensees to measure the Mo-99 concentration of each eluate to detect malfunctioning generators. In April 2002, and because the medical and pharmaceutical community considered the frequency of generator failures to be rare, the NRC revised its regulations to require licensees to measure only the concentration of the first eluate. From October 2006 to February 2007, and again in January 2008, licensees reported that numerous generators had failed testing. The rulemaking returns to the pre-2002 performance standard and again requires licensees to measure the Mo-99 concentration for each eluate. The rulemaking also adds reporting requirements when a generator eluate exceeds permissible Mo-99, strontium-82, or strontium-85 concentrations.

Associate RSOs (ARSOs): Part 35 requires each licensee’s RSO to agree in writing to be responsible for implementing the radiation protection program. And current regulations do not allow more than one permanent RSO to be named on a license. The rulemaking continues to allow licensees to name only one RSO on a license; however, licensees are able to name qualified individuals with expertise in certain uses of byproduct material to serve as ARSOs. ASROs have oversight duties for specified radiation safety operations and report to the RSO, who continues to be responsible for the day-to-day oversight of the entire radiation safety program. ARSOs are required to complete the same T&E requirements as the named RSO for the individual’s assigned sections.

RSOs: Currently, Part 35 allows AUs, AMPs, and ANPs to serve as RSOs for only the licenses on which they are listed. Because AUs, AMPs, and ANPs must meet the same requirements to serve as RSOs regardless of which medical use licenses they are identified on, the NRC believes that it is overly restrictive not to allow them to serve as RSOs on any medical use license. Accordingly, the rulemaking allows an AU, AMP, or ANP listed on any medical use license or permit to serve as an RSO or ARSO. This change increases the number of individuals available to serve as RSOs and ARSOs on NRC medical licenses.

Part 35 contains numerous detailed regulations that affect the practice of radiology, radiation oncology, nuclear medicine, and medical physics. Because of the complexity of the regulations and the lengthy period over which the revisions were accomplished, many radiologists might be uninformed regarding the current status of these regulations and the requirements therein. Given the NRC’s continued interest in the enforcement of these regulations, affected practitioners should ensure that their policies and procedures reflect the regulations’ current requirements.