Answer to Question #1387 Submitted to "Ask the Experts"

Q

In hospitals with nonpatient-related research laboratories where radioactive materials are used (for example, 10 mCi ³²P in an experiment), how far from patient areas should the labs be? Our hospital is considering putting such a lab just around the corner from waiting rooms and other patient areas. It seems like a bad idea to me.

A

There are no specific requirements regarding the distance the laboratory must be from patient waiting areas. Because patients in waiting areas are members of the public, the only requirements in this case are those imposed on doses in unrestricted areas and dose limits to members of the public, as well as ALARA (as low as reasonably achievable). Specifically, Part 20 (Code of Federal Regulations, Title 10, Part 20) requires that doses to members of the public be limited to 100 mrem/yr and be kept ALARA. In addition, doses in unrestricted areas are to be below 2 mrem in any one hour. Therefore, if the lab meets these requirements at the proposed location, it may be established at that location, unless it can be shown that ALARA considerations dictate otherwise. From a radiological controls point of view it may be advisable to consider other, nonregulatory, factors. For example, if unsealed radioactive materials are to be used, ventilation and the flow of air out of the lab to the waiting areas would be an issue, as well as the potential spread of contamination into these areas and the control of access to the lab, which will likely be posted as a restricted area. Security of radioactive materials is also a consideration. Such factors may make establishing the lab at the proposed location less than ideal, but these are not strictly regulatory considerations, but rather organizational and pragmatic.

Sami Sherbini
Nuclear Regulatory Commission