Absorbed dose estimation to family members of patients treated with radioiodine for thyroid cancer

Abstract

Introduction Thyroid remnant ablation with radioiodine is a well-established treatment for patients with Differentiated Thyroid Carcinoma (DTC) following thyroidectomy. After 3–4 days of hospitalization, these patients return home, presenting a possible radiation hazard to their family members. Purpose This work aims at estimating the radiation burden to the cohabitants of DTC patients treated with radioiodine, after hospital release. Materials and methods 724 patients (183/541 men/women) suffering from DTC were treated with radioiodine activities ranging from 1850 to 9250MBq. Thyroid Hormone Withdrawal (THW) was applied in 305 patients (42.1%), whereas 419 (57.9%) patients were prepared with recombinant human TSH (rhTSH). Radioiodine T eff was calculated from dose rate measurements at 1 and 2 m from the patients, performed at regular time intervals throughout their hospitalization. All patients were discharged 3–4 days post-treatment and were provided with written and oral instructions about radiation protection precautions. Patients were grouped according to their family status and radiation doses to their cohabitants were estimated based on appropriate exposure scenarios. Results Mean radioiodine T eff was 15.3 h (range 1.9–37.5 h). T eff in the rhTSH group was lower than the THW group (14.5 h and 17.1 h respectively, p〈0.05). Mean absorbed doses to all family members were estimated to be well below the corresponding dose constraints. Maximum dose to any child was slightly above 0.5 mSv, whereas maximum dose to any non-relative co-traveller was Conclusion Provided necessary precautions are followed, radiation burden to the family members of DTC patients treated with radioiodine following thyroidectomy can be kept lower than the corresponding dose constraints.