Radiation shielding guidance on our website has been updated because of the recent issuance of NCRP Report 147 entitled “Structural Shielding Design for Medical X-Ray Imaging Facilities”.  Among the several recent changes in our website guidance is an increase in the shielding design goal for persons in uncontrolled areas.  Earlier guidance had included the use of a 0.25 mSv per year (25 mrem/year) dose constraint as recommended in the 1993 NCRP 116 report entitled “Limitation of Exposure to Ionizing Radiation.”  In Report 147, a radiation shielding design goal of 1 mGy per year is now recommended, and that new NCRP recommendation has been incorporated into our website guidance.

Because Report 147 is so new, review of that report by regulatory agencies, such as the Radiation Safety Section, and others will likely continue for a while.  In the meantime, if further clarification, addition, revision, or expansion of any shielding guidance items on our website would helpful in light of Report 147, please let us know.