Radiation Exposure to Visitors to Nuclear Medicine Department Waiting Areas

Objectives: The Nuclear Regulatory Commission (NRC) limits the amount of radiation exposure that members of the general public receive from non-patient radioactive sources, and this limit is 20 microsievert (µSv) in any one hour. Visitors to nuclear medicine department waiting areas receive radiation exposure from radioactive patients. The purpose of this research was to prospectively determine if visitors receive radiation exposure greater than 20 µSv from patient sources, which are currently unregulated by the NRC.

Methods: Luxel optically stimulated luminescence (OSL) dosimeters (n=18) were placed on the walls of nuclear medicine department waiting areas in three hospitals, two per waiting area, over the course of three months. At the end of each month the area monitors were sent to Landauer to have their radiation exposure determined, and were replaced with the next set of area monitors. The exposure rate was calculated by dividing the radiation exposure readings received from Landauer by the number of hours the departments were open each month. The average amount of time visitors spent in the waiting areas was observed over one day. The total visitor exposure was calculated by multiplying the average visitor waiting time by the exposure rate. The total visitor exposures for all three hospitals were averaged and compared to the 20 µSv limit for the general public.

Results: The average visitor exposure for all three hospitals was 0.783 µSv and the highest exposure was 2.793 µSv. The average visitor exposure and the maximum exposure were less than the limit for the general public of 20 µSv in any one hour.

Conclusions: Visitors to nuclear medicine department waiting areas do not receive radiation exposure greater than the limit for the general public of 20 µSv for non-patient sources.