10 CFR §35.63

1. (a)A licensee shall determine and record the activity of each dosage before medical use.
2. (b)For a unit dosage, this determination must be made by—
   1. (1)Direct measurement of radioactivity; or
   2. (2)A decay correction, based on the activity or activity concentration determined by—
      1. (i)A manufacturer or preparer licensed under § 32.72 of this chapter or equivalent Agreement State requirements; or
      2. (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
      3. (iii)A PET radioactive drug producer licensed under § 30.32(j) of this chapter or equivalent Agreement State requirements.
3. (c)For other than unit dosages, this determination must be made by—
   1. (1)Direct measurement of radioactivity;
   2. (2)Combination of measurement of radioactivity and mathematical calculations; or
   3. (3)Combination of volumetric measurements and mathematical calculations, based on the measurement made by:
      1. (i)A manufacturer or preparer licensed under § 32.72 of this chapter or equivalent Agreement State requirements; or
      2. (ii)A PET radioactive drug producer licensed under § 30.32(j) of this chapter or equivalent Agreement State requirements.
4. (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.
5. (e)A licensee shall retain a record of the dosage determination required by this section in accordance with § 35.2063.