Re: Criteria for release of cats that received I-131 therapy

[BLHamrick@AOL.COM]

In a message dated 4/9/2004 8:08:31 AM Pacific Standard Time, 

ljb1@CORNELL.EDU writes:

We are wondering what criteria other vet nuclear medicine facilities are 

being held to in terms of release of cats that have received I-131 

therapy.  We are held to a minimum stay time (5 days), a maximum dose rate 

at a foot from the thyroid (0.5 mrem/h) and a maximum activity remaining in 

the cat (200 uCi).  We would also like to know what regulatory agency is 

involved with that criteria.

This will vary based on the regulatory agency with jurisdiction over 

byproduct material state to state.  There are currently 33 Agreement States in the 

U.S., which regulate the possession and use by byproduct material (including 

I-131) under an agreement with the U.S. NRC.  In the remaining states, the NRC 

retains jurisdiction over the possessiona nd use of the materials.



Below is the guidance provided by NRC in NUREG 1556, Vol. 7, Appendix H:



"Release of Animals

Before a veterinarian releases an animal that has been injected with a 

radiopharmaceutical or has had radioactive seeds implanted, the veterinarian must 

ensure that the dose that members of the public (including the animal's 

caretaker) will receive from the animal is within limits of 10 CFR 20.1301. 10 CFR 

20.1301 requires that the total effective dose equivalent to an individual member 

of the public from the licensed operation does not exceed 1 mSv (0.1 rem) in 

a year and the dose in any unrestricted area from external sources does not 

exceed 0.02 mSv (0.002 rem) in any one hour. Furthermore, licensees should 

provide instructions to the animal's caretaker to keep doses ALARA."

States may provide similar guidance, or, as it appears in your case, may 

provide actual dose-rate limitations (usually via a license condition) on the 

animals such that they will generally meet the public dose limits upon release.

Barbara