mined by direct measurement, a combination of measurement of radioac-
tivity and mathematical calculations, or a combination of volumetric mea-
surements and mathematical calculations based on the activity provided by
the manufacturer.
Unless otherwise directed by the authorized user, the licensee may not
use a dosage if it does not fall within the prescribed dosage range, or if it
differs from the prescribed dosage by more than 20%. The licensees who
use only unit dosages supplied by the manufacturer may not need to have
a dose calibrator.
Calibration, Transmission, and Reference Sources
The following sources of by-product material are permitted for check, cal-
ibration, transmission, and reference use (10CFR35.65):
(a) Sealed sources not exceeding 30 mCi (1.11 GBq) manufactured and
supplied by a licensed manufacturer, or a licensee authorized to redis-
tribute such sources
(b) Any by-product material with a half-life not longer than 120 days in
individual amounts not exceeding 15 mCi (0.56 GBq)
(c) Any by-product material with a half-life longer than 120 days in indi-
vidual amounts not to exceed the smaller of 200mCi (7.4 MBq) or 1000
times the quantities in Appendix B of 10CFR30
(d) 99mTc in amounts as needed
A licensee may only use sealed sources for medical use, manufactured by
a licensed manufacturer (10CFR49).
Requirement for Possession of Sealed Sources
According to 10CFR35.67, sealed sources of radionuclides with a half-
life greater than 30 days and containing more than 100mCi (3.7 MBq) of g-
emitting material or more than 10mCi (370 kBq) a-emitting material must
be leak tested and inventoried semiannually. If a source shows a leak of
0.005mCi (185 Bq) or more of removable contamination, it must be imme-
diately removed from use and stored, disposed of, or repaired according to
regulations, and a report must be filed with the NRC within five days of the
leak test describing the source involved, the test results, and the action
taken.
Labeling of Vials and Syringes
Each syringe and vial containing radioactivity must be labeled to identify
the radioactive drug (10CFR35.69). Each syringe or vial shield also must
286 16. Radiation Regulations and Protection