[Radioiodine therapy of differentiated thyroid cancer: radiologic impact of out-patient treatment with 100 to 150 mCi Iodine-131 activities].

PURPOSE: To evaluate exposure and dosimetry to family members and environment due to outpatient radioiodine therapy of differentiated thyroid carcinoma.

METHODS: Twenty patients were treated with 100-150mCi of iodine-131 on an out-patient basis. Family members dosimetry (n = 27) and potential doses inside the house were measured with thermoluminescent dosimeters. Surface contamination and radioactive wastes were also monitored.

RESULTS: Less than 1.0 mSv doses were found in 26 co-habitants and 2.8 mSv in a single case (inferior to the acceptable value of 5.0 mSv/procedure). Potential doses in the houses were inferior to 0.25 mSv, excluding the patients bedroom (mean value = 0.69 mSv). Surface contamination (mean = 4.2 Bq.cm-2) were below clearance levels. Radioactive wastes generated had a volume of 2.5 liters and a total activity estimated in 90 microCi, with a calculated exposure close to the background radiation levels.

CONCLUSIONS: No radiological impact was detected after iodine therapy with 100-150 mCi on an out-patient basis followed by experienced professionals.