Ring Badges

[ehsnet!hps (HPS)]

Reply-to: Wes.Dunn@p2.f13.n233.z1.fidonet.org (Wes Dunn)
Fido-To: steven hand

Under the current (and new) 10CFR20, dosimetry requirements are performance driven.  If you can demonstrate that individuals don't have significant exposures below a certain threshold, dosimetry isn't necessary.  Now, some licensees may commit to absolute requirements (often at the request of the regulatory Agency), but it should take little effort to show when finger badges should be worn.  Under the new Part 20, you need to show an exposure greater than 10% of the annual limit (50 Rem) would be unlikely at your action level.  Individuals using less than 1 mCi of P-32 at a time should not come close to 5 Rem to the finger/year unless they are using extremely poor lab techniques.  The solution is to correct their bad habits, not make them wear ring badges.  I would suggest a policy for high energy Beta emitters of badging individuals using at least 1 mCi batches for a time period.  This is in line with current Texas guidelines (Note that until 1/1/94, Texas requires everyone to wear whole body badges unless specifically exempted).

If they show low exposures, then up the limit to 5 mCi.  If they do higher exposures, make sure they get more training on proper techniques.  If your institution has a history of high exposures at 1 mCi or less, you might want to lower these levels until this is remedied.

And yes, finger rings should be worn on the inside of the finger so that it isfacing the source.  Under the new Part 20, the extremity dose is the skin dose.  So it doesn't make sense to only measure radiation that has to penetrate the finger to be detected.

(Standard Disclaimer include the following: I sure hope I quoted the right numbers.  We (Texas Bureau of Radiation Control) just changed 9 section of our regulations and we hardly have time to figure out how the new Part 20 is going to really impact things.  Isn't that what December is for?)

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 * Origin: Health Physics Liberation Front  (1:233/13.2)
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