Radiation exposure for 'caregivers' during high-dose outpatient radioiodine therapy

On 27 occasions, radiation doses were measured for a family member designated as the 'caregiver' for a patient receiving high-dose radioiodine outpatient therapy for differentiated thyroid carcinoma. For 25 of the administrations, patients received 3.7 GBq of 131I. Radiation doses for the designated caregivers were monitored on an hourly basis for 1 week using electronic personal dosemeters. The average penetrating dose was 98±64 μSv. The maximum penetrating dose was 283 μSv. Measured dose rate profiles showed that, on average, one-third of the caregiver dose was received during the journey home from hospital. The mean dose rate profile showed rapid clearance of 131I with three distinct phases. The corresponding clearance half-times were <1 h, 21 h and ∼8 d. These components were associated, respectively, with the drive home, the clearance of radioiodine from an athyreotic patient and small quantities of 131I contaminating the home. (authors)