Radioactive waste discharge quantities for patients undergoing radioactive iodine therapy for thyroid carcinoma

There is a need to provide realistic estimates of the activity discharged to the drains by patients undergoing procedures involving unsealed radionuclides. These estimates are essential for record keeping purposes, to demonstrate compliance with limits set in waste disposal authorizations and for planning new installations. In this study, we report the discharge of activity for 174 patients (202 treatments) undergoing treatment of thyroid carcinoma with radioactive iodine. We have found that approximately 55% of administered activity is excreted in the first 24 h and that 85% of administered activity is discharged to the sewer over a typical inpatient stay of 5 days. There was no significant difference in levels of discharge between those patients undergoing inaugural ablation therapy and those having further treatments with radioactive iodine.