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

[BLHamrick@AOL.COM]

In a message dated 4/11/2004 12:17:58 AM Pacific Standard Time, 

email@philrutherford.com writes:

However, as a practical matter, human patients are apparently not restricted 

from release following these everyday procedures. 

In fact, 10 CFR 35 allows patients to be released if the expected maximum 

dose to another person will not exceed 500 millirem.  NUREG 1556, Vol. 9, 

Appendix U provides guidance on determining whether or not this limit will be 

exceeded.  It actually provides that a patient may be released without instruction if 

the remaining activity is less than 760 mCi for Tc-99m.  Given that the 

average dosages for Tc-99m generally don't exceed 25 mCi, and that for other common 

nuclides, the numbers are all well over the average dosages administered, 

virtually all diagnostic patients are releasable without a second thought.  



Part 35 is devoted to human medical use, and the 500 millirem limit 

supercedes the 100 millirem limit in Part 20.  Veterinary practice does not fall under 

Part 35 regulations, therefore must comply with the Part 20 limits.  I'm not 

saying it makes sense, necessarily, but it does in a way if you follow the 

development of the regulations.



Barbara