The Removal of legacy 226Ra and 137Cs Medical Sources from Paraguay to the United States Under the International Atomic Energy Agency’s Global 226Ra Management Initiative

OBJECTIVE: To describe the transfer of six decommissioned legacy 226Ra sources totaling 9.92 ± 2.0% GBq (268 mCi), and 116 decommissioned 137Cs sources totaling 41.1 ± 2.0% GBq (1,110 mCi), from the Republic of Paraguay to the United States, within the framework of the International Atomic Energy Agency's Global Radium-226 Management Initiative. METHODS: The sources were removed from their original shielded packaging, a cement-filled 200-L steel drum. The sources were identified via spectroscopic analysis, assayed, and repackaged in six Type A containers; five containers contained 226Ra sources, and one contained all the 137Cs sources. The containers were wipe-tested, and dose rates on contact and at 1.0 m were measured. RESULTS: External wipe tests on the containers revealed counts slightly above natural background in one of the units (14% above background), well below the allowable surface contamination for a II-Yellow-coded (medium risk) Type A container. Dose rates at 1.0 m for all containers (i.e., their transport indices) ranged between 1.1 μSv h-1 ± 10% (0.11 mrem h-1) and 4.4 μSv h-1 ± 10% (0.44 mrem h-1), also corresponding to a II-Yellow code. Thus all containers were II-Yellow-coded for air shipment to the United States. The transfer of the containers from hospital to airport, inspection, weighing at customs, and loading onto the aircraft proceeded without incident. CONCLUSIONS: The safe transfer of decommissioned 226Ra and 137Cs medical sources from possessor to receptor countries is possible provided all national and international safety guidelines are adhered to. Based on our experience, we recommend that any country considering such a transfer avail itself of the safety and security standards associated with the International Atomic Energy Agency's Global Radium-226 Management Initiative.