10 CFR § 35.63 - Determination of dosages of unsealed byproduct material for medical use.

---
identifier: "/us/cfr/t10/s35.63"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "10 CFR § 35.63 - Determination of dosages of unsealed byproduct material for medical use."
title_number: 10
title_name: "Energy"
section_number: "35.63"
section_name: "Determination of dosages of unsealed byproduct material for medical use."
chapter_name: "NUCLEAR REGULATORY COMMISSION"
part_number: "35"
part_name: "MEDICAL USE OF BYPRODUCT MATERIAL"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Atomic Energy Act of 1954, secs. 81, 161, 181, 182, 183, 223, 234, 274 (42 U.S.C. 2111, 2201, 2231, 2232, 2233, 2273, 2282, 2021); Energy Reorganization Act of 1974, secs. 201, 206 (42 U.S.C. 5841, 5846); 44 U.S.C. 3504 note."
regulatory_source: "67 FR 20370, Apr. 24, 2002, unless otherwise noted."
cfr_part: "35"
---


# 35.63 Determination of dosages of unsealed byproduct material for medical use.

(a) A licensee shall determine and record the activity of each dosage before medical use.

(b) For a unit dosage, this determination must be made by—

(1) Direct measurement of radioactivity; or

(2) A decay correction, based on the activity or activity concentration determined by—

(i) A manufacturer or preparer licensed under § 32.72 of this chapter or equivalent Agreement State requirements; or

(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

(iii) A PET radioactive drug producer licensed under § 30.32(j) of this chapter or equivalent Agreement State requirements.

(c) For other than unit dosages, this determination must be made by—

(1) Direct measurement of radioactivity;

(2) Combination of measurement of radioactivity and mathematical calculations; or

(3) Combination of volumetric measurements and mathematical calculations, based on the measurement made by:

(i) A manufacturer or preparer licensed under § 32.72 of this chapter or equivalent Agreement State requirements; or

(ii) A PET radioactive drug producer licensed under § 30.32(j) of this chapter or equivalent Agreement State requirements.

(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.

(e) A licensee shall retain a record of the dosage determination required by this section in accordance with § 35.2063.

[67 FR 20370, Apr. 24, 2002, as amended at 72 FR 55931, Oct. 1, 2007]