Re: X-Ray Shielding Requirements

["Wesley M. Dunn" <WDUNN@brc1.tdh.texas.gov>]

> From: MAJ Don Jordan <djordan@osiris.cso.uiuc.edu>
> Subject: X-Ray Shielding Requirements
>
> I am looking for any information relating to the practical impact of
> the 100 mrem nonoccupational annual dose limit on medical/industrial
> x-ray facilities whose shielding requirements were initially
> determined using NCRP 49 and the previous 500 mrem/yr nonoccupation
> dose limit.

Well, Texas deemed this to be a significant problem.  So TRCR
21.301(a)(2) [Part 21 is equiv to 10CFR20] allows a TEDE of 500
mrem/year for members of the public "from infrequent exposure
to radiation from diagnostic and therapeutic radiation machines".

In addition, a footnote to 21.301(a)(1) exempts radiation machine
facilities who met the previous dose limits (500 mrem/year) from
having to retrofit if they were installed prior to 1/94.


Wes Dunn
Texas Bureau of Radiation Control