Assessment of intake and internal dose from iodine-131 for exposed workers handling radiopharmaceutical products

Two methods for determination of internal dose due to I-131 intake during the preparation and handling of iodine radiopharmaceutical products have been compared. The first method was based on the measurement of I-131 in 24-hour urine samples while the second method was based on the measurement in vivo of I-131 in thyroid. The results have shown that urine analysis method can be used as a screening test but not for internal dose assessment of exposed workers. Thyroid monitoring method was found to be more reliable and accurate method for assessing internal dose from I-131 intake. In addition, the assessed internal dose showed that the annual internal effective dose for some workers was below 1 mSv with no risk classification, whereas the results of other group of workers were between 1 and 6 mSv with low risk classification. Only one worker reached 7.66 mSv with high risk classification; and this worker must be monitored individually. (C) 2013 Elsevier Ltd. All rights reserved.