Analysis of the antidote requirements and outcomes of different radionuclide decorporation strategies for a scenario of a "dirty bomb" attack.

Objective: In radiological emergencies, there is a risk of radionuclide incorporation. The radiological doses absorbed can be reduced by decorporation treatment. Antidote requirements depend on the scenario and treatment strategy ("urgent approach": immediate treatment of all patients with possible incorporation; "precautionary approach": treatment only after confirmation of incorporation). We calculated the number of daily antidote doses for different scenarios and the differences in outcome for both treatment strategies.

Design: The number of potentially contaminated victims was varied from 1,000 to 60,000 (a maximum that might seem plausible for "dirty bomb" scenarios in Germany), the proportion of patients actually needing decorporation treatment from 0.1 percent to 100 percent, the radioactive screening capacities from 250 to 2,500 people/day and treatment duration from 10 to 90 days. The outcomes were assessed as total statistical lifetime saved assuming an inhalation of 1 mCi cesium-137 and the achievable dose reductions by a Prussian Blue treatment.

Results: Assuming 1 percent of the potentially contaminated people actually needing treatment, applying an "urgent approach" the requirements for 1,000 victims range from 1,100 to 3,400 and for 60,000 victims from 489,000 to 4,400,000 daily doses, depending on treatment duration and screening capacities. The "urgent approach" is associated with larger stockpile requirements than the "precautionary approach", up to several hundred times in large-scale scenarios if the proportion of people actually needing treatment is low. The impact of the screening capacities is particularly important in large-scale scenarios, a low proportion of people needing treatment and extended treatment duration. The outcome is better for an "urgent approach" particularly in large-scale scenarios and low screening capacities.

Conclusions: If only a small fraction of the victims actually needs treatment, their timely identification by enhancing screening capacities may be the most efficacious way to reduce antidote requirements. In large-scale scenarios, it might be necessary to abandon the medically preferable "urgent approach" for an antidote-sparing "precautionary approach".