On May 18, 2026, the U.S. Nuclear Regulatory Commission announced a landmark proposed rule that would transform the regulatory landscape for medical isotopes. The rule, Modernizing NRC Regulations for Byproduct Material Use (RIN 3150-AL49, Docket No. NRC-2025-1205), addresses long-standing inefficiencies in the licensing framework governing byproduct material, which encompasses virtually every radioisotope used in nuclear medicine.[1] When it becomes final, the rule will amend eight parts of Title 10 of the Code of Federal Regulations (10 CFR Parts 30, 31, 32, 34, 39, 40, 70 and 150) and represent the NRC’s most consequential action in this space in nearly two decades.
The rule responds directly to President Donald Trump’s Executive Order 14300 (“Ordering the Reform of the Nuclear Regulatory Commission,” May 23, 2025) and the bipartisan ADVANCE Act of 2024. E.O. 14300 directed the NRC to eliminate unnecessary regulatory burdens, expedite licensing timelines, and adopt risk-informed approaches that align with modern radiopharmaceutical production practices. The ADVANCE Act further reinforced these objectives by mandating that the NRC streamline its licensing processes for medical and research applications while maintaining robust safety standards.
For sponsors and operators in the radiopharmaceutical sector, the rule offers meaningful deregulatory relief — most notably, the elimination of decommissioning financial assurance (DFA) for short-lived therapeutic isotopes and a 100-fold relief in DFA thresholds for Ge-68/Ga-68 generators.
Although E.O. 14300 mandates that a final rule and any guidance be issued by Nov. 23, 2026, the NRC’s projected publication date extends to March 31, 2027. [2] The NRC also expects to release a second proposed rulemaking, Reducing Barriers to Medical Use Licensing (RIN 3150-AL50; 10 CFR Part 35), later this quarter. Together, these two rules advance the objectives of E.O. 14300 and will cover the full nuclear medicine supply chain from manufacturing and distribution through dispensing and administration.
I. Core Regulatory Changes for Byproduct Material Licensees
A. Decommissioning Financial Assurance Relief Under Appendix B
For sponsors and operators, the most significant immediate financial impact comes from proposed changes to Appendix B of 10 CFR Part 30. This appendix sets the rules for DFA—essentially, the bonds and reserves that licensees must maintain to cover cleanup costs when a facility shuts down. Two proposed changes deserve careful review:
First, the rule removes all radionuclides with half-lives of 120 days or less from DFA calculations. This effectively eliminates DFA obligations for the entire current generation of therapeutic radioligands, including Lu-177 (6.7-day half-life), Y-90 (2.7 days), Ac-225 (10 days), Ra-223 (11.4 days) and shorter-lived alpha and beta emitters under clinical development. The NRC concludes that “short-lived radionuclides do not require major decommissioning efforts, as radionuclides with half-lives of 120 days or less naturally decay to negligible levels within a few years.” [3] The 120-day threshold has been embedded in § 30.35 since the NRC’s original 1988 decommissioning financial assurance framework, reflecting the long-standing technical judgment that a radionuclide with a half-life of 120 days or less will pass through roughly 10 half-lives, and thus decay to effectively background levels, within approximately three to four years. The present rulemaking accordingly does not create the exemption so much as conform Appendix B to the operative criterion in § 30.35.
Second, the rule gives Ge-68 and several other naturally occurring or accelerator-produced radionuclides (NARM) specific listings at risk-appropriate thresholds. Under current default values, Ge-68/Ga-68 generators trigger DFA at extremely low possession quantities — possession of more than 0.1 millicurie of certain unsealed isotopes triggers $225,000 in DFA, and possession above 1 millicurie triggers $1,125,000. The proposed rule adjusts the default values and lists Ge-68 at 10 microcuries — a roughly 100-fold increase in the minimum DFA threshold. Industry has been calling for this change for years. The Advisory Committee on the Medical Uses of Isotopes (ACMUI) concluded in 2015 that current DFA requirements were “preventing and/or deterring the use of promising Gallium-68 (Ga-68) diagnostic imaging agents for patients.” [4]
Investor implication
The practical significance of conforming Appendix B to the operative criterion in § 30.35 is substantial. It removes a recurring compliance burden for licensees whose inventories consist almost entirely of short-lived isotopes, and it eliminates a structural disincentive to the development and adoption of next-generation theranostic agents. For sponsors active in theranostics, radiopharmacy networks and freestanding imaging operators, the change also removes a contingent liability that has historically complicated diligence, balance sheet treatment and exit modeling for targets whose isotope inventories are dominated by short-lived agents. The Organization of Agreement States, in its petition PRM-30-66 that prompted this rulemaking, specifically noted that the current framework “puts an undue hardship on certain licensees with little or no radiation safety benefit, discourages the development of new beneficial products, and negatively impacts patient care.” [5]
For sponsors building Ga-68-dependent platforms, the proposed 100-fold increase in the Appendix B value materially improves the scalability of multi-site generator deployment, eliminates a recurring class of regulatory friction in add-on acquisitions and converts what has historically been a site-by-site exemption process into a predictable threshold that can be modeled in advance.
B. Microsource and Microsphere Distribution (§§ 32.72 and 32.74)
The NRC has proposed amendments to 10 CFR Part 32 that would, for the first time, permit commercial radiopharmacies to prepare and distribute radioactive microspheres. The changes are driven in significant part by USP General Chapter <825>, which now sweeps sterile intravascular radioactive devices into a preparation and compounding framework historically applied to radiopharmaceuticals. The sections below describe the existing regulatory architecture, the specific revisions on the table, and what the changes are likely to mean in practice for radiopharmacy operators, treating facilities, and the investors backing them.
Under current Part 32, two distinct commercial distribution pathways exist: § 32.72 covers radioactive drugs, and § 32.74 covers sources and devices containing byproduct material. Because FDA regulates microspheres as medical devices, they are commercially distributed under § 32.74 and used medically under § 35.1000 as brachytherapy sources and devices, rather than under the radioactive-drug framework that applies to most radiopharmaceuticals. USP General Chapter <825>, however, draws sterile intravascular radioactive devices into the same preparation, compounding, dispensing and repackaging framework that governs radiopharmaceuticals, including a requirement that sterile microspheres used more than one hour after vial puncture be prepared in an ISO Class 5 environment. The mismatch is structural: commercial radiopharmacies have the engineering controls and trained personnel that <825> contemplates, but their § 32.72 commercial distribution authority covers radioactive drugs — not devices — so they cannot currently prepare and commercially distribute patient-ready microsphere doses in the way they do for FDG, DOTATATE or PSMA agents.
The proposed amendments accomplish three objectives:
- Expands § 32.72 to cover microsources, allowing § 32.72-licensed radiopharmacies to prepare and distribute microspheres. The amendments also broaden the provision to apply to any applicant legally authorized under federal or state law to manufacture, compound, prepare or distribute radioactive drugs or medical devices.
- Revises § 32.74 with microsource-specific provisions, confirming that licensees may use either § 32.72 or § 32.74 to distribute microsources and clarifying that distribution is permitted to any licensee authorized to use the source or device under Part 35.
- Makes a conforming change to § 30.32 to reflect the restructured § 32.72.
The amendments are intended to reduce regulatory burden, improve clarity for regulators and licensees alike, allow licensees to select the distribution framework that fits their business model, support USP <825> compliance, and preserve timely patient access to microsphere therapy without compromising public health and safety.
Investor implication
For sponsors invested in commercial radiopharmacy networks, interventional oncology platforms or theranostics-adjacent imaging operators, the structural gap between § 32.72 (radioactive drugs) and § 32.74 (sources and devices) has meaningfully constrained the commercial radiopharmacy thesis. The proposed amendments represent a material expansion of the addressable market for radiopharmacy platforms and should trigger a corresponding revaluation of acquisition targets in this space. With these amendments, supply-chain bottlenecks should ease over time, though the pace of relief will depend on radiopharmacy microsphere adoption and the time it may take to layer device-specific elements onto existing drug cGMP frameworks.
FDA device-specific elements
When a product contains a device and a drug constituent, 21 CFR Part 4 requires compliance with FDA’s device-focused quality management system regulation (QMSR) and drug-focused cGMPs of Part 211/212, typically through a single integrated quality system. For radiopharmaceutical manufacturers already operating under Part 212, this generally means layering device-specific QMSR elements onto existing drug cGMP frameworks rather than building parallel systems from scratch. The most substantial additions are design controls, ISO-14971 risk management, formal device CAPA and supplier qualification at the rigor ISO-13485 requires. Facility, environmental monitoring, materials handling, lot release and personnel training procedures generally carry over with some revisions.
C. Expanded Consortium Arrangements for PET Production (§ 30.4) — Distance Limitation Repealed
The rule removes a longstanding geographic restriction to the definition of “consortium,” the pooled-cost arrangement under which medical-use licensees and a PET radionuclide production facility share operating expenses. Under current practice, a production facility must sit in the same geographical area as a medical use licensee. This requirement reflects historical concerns about transporting short-lived isotopes such as F-18 (1.8-hour half-life). The NRC concedes the restriction had no safety basis but was established due to supply chain constraints. [6] With this provision gone, longer-lived PET radionuclides, particularly Cu-64 (12.7 hours) and Ga-68, will be able to be produced at centralized hubs and shipped to consortium members regardless of distance. One important caveat: The consortium production site must still be a noncommercial facility (educational, federal or medical). Commercial PET manufacturers still need § 32.72 distribution licenses and do not benefit directly.
Expect to see more cost-effective regional PET production models, with development and collaboration opportunities across academic-federal-medical partner groups.
D. New Standard General License (§ 31.16) — Streamlined Access for Diagnostic Nuclear Medicine, Not Therapeutics
The rule creates a new class of “Standard General Licenses” (SGLs), which will be a streamlined licensing pathway requiring only registration, fee payment and certification of understanding (rather than the more burdensome specific license process). NRC proposes a new class of SGLs for low-risk activities that are currently specifically licenses, including fixed gauging, portable gauging, certain medical uses, and certain analytical equipment uses, and certain in vitro testing uses. For medical uses, the SGL under covers unsealed gallium-67, indium-111, iodine-123, iodine-125, iodine-131, technetium-99m, thallium-201 and xenon-133 for diagnostic uses when no written directive is required; Mo-99/Tc-99m generators; and calibration, transmission and reference sources. The SGL pathway will mandate inventory limitations designed to prohibit a single general licensee from aggregation of materials requiring implementation of requirements contained in 10 CFR Part 37, materials requiring a decommissioning plan or financial assurance, and materials requiring an emergency plan.
The SGL is not a therapeutic licensing pathway. Any administration requiring a written directive, such as Lu-177 PSMA, I-131 therapy, Y-90 microsphere therapy or Ac-225 therapy, remains on the specific license track. It also does not authorize Ga-68 or Cu-64. The NRC explains in the proposed rule that adding PET radionuclides or non-Mo-99/Tc-99m generators “would not meet the essential objective for this requirement as these radionuclides or uses require additional licensing requirements to ensure an adequate level of safety.” [7]
Mobile medical services are also excluded, and possession is capped below Category 2 thresholds in 10 CFR Part 37, below DFA-triggering thresholds and below emergency planning thresholds.
Lastly, Agreement State adoption of the SGL pathway is voluntary, so adoption timelines and implementation details will vary by state.
Investor implication
Investors should not assume the SGL accelerates therapeutic site rollout. RLT treatment center platforms should continue to plan around full specific license timelines for new sites. The SGL is genuinely useful for diagnostic-only nuclear medicine practices and certain Tc-99m-focused operations. That is the universe in which the value should be modeled. Multi-state operators also plan for a patchwork period during which SGL eligibility will not be uniform across their footprint. Diligence should include a state-by-state assessment of Agreement State adoption posture for any platform with operations in multiple jurisdictions.
E. Reciprocity Reforms (§ 150.20)
The proposed rule would streamline the framework that lets NRC and Agreement State licensees work across jurisdictional lines. The initial reciprocity filing notice drops from three days before activity to the day of. Offshore licensees no longer need to amend NRC Form 241 for changes in work location. Reciprocity would also extend to SGLs, allowing them to work in NRC jurisdictions for up to 180 days per calendar year.
Investor implication
For national-scale radiopharmaceutical distributors, manufacturers and centralized treatment networks, this offers additional operational flexibility, especially for emergency procedures, urgent diagnostic studies and time-sensitive theranostic patient care.
II. Recommended Actions
For acquisitions or follow-on investments closing in the next 12 months, three points of diligence should move to the front of the checklist:
- DFA carrying-cost savings should be modeled as a near-term EBITDA tailwind;
- Microsphere supply chain capabilities should be assessed under the expanded § 32.72 framework — both as a value driver for sellers and as a competitive consideration for buyers building radiopharmacy platforms;
- Target license diligence should map which licenses may benefit from transitioning to SGL post-rule and which should stay on the specific-license track.
Q2 and Q3 2026:
- Identify assets with material DFA postures and quantify DFA cost savings.
- Evaluate platforms for potential microsphere expansion and whether to license under the expanded § 32.72 or § 32.74 pathway based on business-model fit.
- Engage with industry trade associations (SNMMI, CORAR, Health Physics Society, Coalition of PET Drug Manufacturers) to align on coordinated comment positions.
- Coordinate engagement on the companion Reducing Barriers to Medical Use Licensing rule (RIN 3150-AL50).
- Track ACMUI subcommittee output on the proposed rule; ACMUI recommendations carry more weight in the final rule than most third-party comments. The subcommittee will make its recommendations to the full committee on the proposed rule at a publicly held teleconference during the public comment period.
III. Closing Observation
This proposed rule marks a pivotal moment for the radiopharmaceutical industry — one that creates meaningful opportunities for investors and positions the sector for continued growth and innovation.
McGuireWoods is tracking this rulemaking and the companion Part 35 rulemaking closely. For questions about the proposed rule, comment strategy or portfolio company impact assessments, contact the authors, Kevin M. Madagan or Jessia L. Vaughn, Ph.D., or a member of the Life Sciences Industry Group.
[1] The NRC has also prepared interim staff guidance document Guidance for the Implementation of 10 CFR Part 31 Subpart C Standard General Licenses and Guidance on Reciprocity.
[2] 91 Fed. Reg. 289169 (May 18, 2026) (Proposed Rule).
[3] Proposed Rule, pg. 28920. An important caveat: accelerator-produced Ac-225 may contain Ac-227 impurity (up to 2%), which has a 21.8-year half-life and the 120-day exemption does not cover it. Licensees handling accelerator-produced Ac-225 should confirm their supply source and impurity profile to determine whether DFA obligations remain for the Ac-227 component.
[4] ACMUI, Germanium-68 (Ge-68) Decommissioning Funding Plan (DFP), Final Report (Aug. 12, 2015), pg. 1.
[5] OAS Petition for Rulemaking: Revision of 10 CFR 30 Appendix 8 (2017).
[6] Proposed Rule, pg. 28919.
[7] Proposed Rule, pg. 28933.