US NRC 10 CFR Part 35 (Medical Use of Byproduct Material)

Title 10, Part 35 of the US Code of Federal Regulations is the US Nuclear Regulatory Commission's rule set governing the medical use of byproduct (radioactive) material. It covers licensing of authorised users, authorised nuclear pharmacists and authorised medical physicists (Subparts A-C); unsealed material used without a written directive, such as diagnostic uptake and imaging studies (Subpart D); unsealed material requiring a written directive, i.e. most therapeutic radiopharmaceuticals (Subpart E); manual brachytherapy (Subpart F); sealed diagnostic sources (Subpart G); teletherapy and afterloader units (Subpart H); other medical uses (Subpart K, section 35.1000); and recordkeeping, reporting and enforcement (Subparts L-N).

Part 35 sets the practical requirements that shape how lutetium-177, actinium-225, iodine-131 and other therapeutic radiopharmaceuticals are prescribed and administered in the United States: written directives, dose measurement before administration, medical event reporting thresholds, and patient-release criteria after therapy (35.75). NRC licenses cover roughly 40% of medical byproduct-material use directly; the remainder is regulated by 39 Agreement States that adopt compatible rules, so Part 35 also functions as the de facto national baseline.

The regulation text itself is freely available and is a primary source for approvals-adjacent facts (dose thresholds, reporting triggers) that should be cited directly rather than paraphrased from secondary summaries.