The article “Exposure to Technologists from Preparing and Administering Therapeutic 131I: How Frequently Should We Bioassay?” by Kopisch et al. (J Nucl Med Technol. 2011;39:60–62) contained a mathematic error in the “Results” paragraph. The corrected paragraph appears below. The authors regret the error.From these data, one learns that an average air concentration of 0.0024E−03 kBq/mL (6.4E−05 μCi/mL) of air can be expected from the handling and administration of a dose of 5.74 GBq (155 mCi) of 131I. The NRC assumption for its derived air concentration calculations is that an average worker inhales approximately 20 L of air per minute. A technologist utilizing a full 10 min of 131I handling for a procedure would inhale about 200 L of air. One could project a total ingestion for the technologist of 0.481 kBq (0.013 μCi) during such a procedure.