{"data":{"id":"us/10-cfr-35.63","jurisdiction":"us","citation":"10 CFR 35.63","heading":"Determination of dosages of unsealed byproduct material for medical use.","body":"(a) A licensee shall determine and record the activity of each dosage before medical use.\n(b) For a unit dosage, this determination must be made by—\n(1) Direct measurement of radioactivity; or\n(2) A decay correction, based on the activity or activity concentration determined by—\n(i) A manufacturer or preparer licensed under § 32.72 of this chapter or equivalent Agreement State requirements; or\n(ii) An NRC or Agreement State licensee for use in research in accordance with a Radioactive Drug Research Committee-approved protocol or an Investigational New Drug (IND) protocol accepted by FDA; or\n(iii) A PET radioactive drug producer licensed under § 30.32(j) of this chapter or equivalent Agreement State requirements.\n(c) For other than unit dosages, this determination must be made by—\n(1) Direct measurement of radioactivity;\n(2) Combination of measurement of radioactivity and mathematical calculations; or\n(3) Combination of volumetric measurements and mathematical calculations, based on the measurement made by:\n(i) A manufacturer or preparer licensed under § 32.72 of this chapter or equivalent Agreement State requirements; or\n(ii) A PET radioactive drug producer licensed under § 30.32(j) of this chapter or equivalent Agreement State requirements.\n(d) Unless otherwise directed by the authorized user, a licensee may not use a dosage if the dosage does not fall within the prescribed dosage range or if the dosage differs from the prescribed dosage by more than 20 percent.\n(e) A licensee shall retain a record of the dosage determination required by this section in accordance with § 35.2063.","path":["Title 10—Energy","CHAPTER I—NUCLEAR REGULATORY COMMISSION","PART 35—MEDICAL USE OF BYPRODUCT MATERIAL","Subpart C—General Technical Requirements"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-10.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:09Z","sha256":"4edc4fa91acd23245d0bda941aca8ff832c5b15290d6ed2b1d12d90ebe668a72","source_id":"us-cfr","stale":true,"prev":"us/10-cfr-35.61","next":"us/10-cfr-35.65"},"notice":"GroundRules: Original legal text. Not legal advice."}