Measurement of radiation exposure to household contacts of patients with Graves disease treated with low dose radioactive iodine (¹³¹I) on outpatient basis

Patients with Graves disease (GD) treated with ¹³¹I represent potential radiation hazard to others including household contacts. Radiation safety is considered an integral part in the protocol of this therapeutic modality. Each center offering this medical service gives specific protective recommendations that should help to ensure compliance with guidelines and radiation precaution regulations for each country, with a final aim of reducing potential harmful radiation exposure to others. Aim: We aimed at evaluation of how safe is the use of low dose ¹³¹I in the treatment of patients with Graves disease on outpatient basis and assessment of compliance of patients and their household contacts to radiation safety instructions (RSI). Measurement of cumulative radiation exposure (CRE) to household contacts and radiation exposure rate (RER) to household environment were our tools. Another aim was looking for patients and contacts factors that can significantly affect CRE to household contacts. Patients and methods: RSI were properly explained in details by qualified professionals to 23 patients with GD and 39 out of 117 household contacts. Patients received ¹³¹I doses ranging from 370 to 740 MBq. Measurements of contacts CRE and RER in different household areas were done five days post ¹³¹I therapy. CRE figures were correlated with different demographic and educational factors of both patients and contacts. Results: All CRE figures were well below 1 mSv, ranging from 0.079 to 0.992 mSv. All household environment RER were also below constraint. No single studied demographic or educational factor had statistically significant correlation with CRE, yet contacts who attended direct RSI education sessions had relatively lower CRE figures. Conclusion: Treatment of GD with ¹³¹I on out patient basis is a safe therapeutic modality with no single household contacts or household environment radiation over exposure, providing RSI are given in a proper way by qualified professionals with an advice to be given to all patients household contact