The infusion of contrast solution into multiple patients from a single infusion bag is desired in clinics concerned with the high cost of the solution. Using one-way check valves in the infusion line is a protection method to reduce the risk of blood-borne cross-contamination. The suitability of this method is assessed through testing of the operating characteristics of the valves and infusion system and the high back pressure testing of the valves. The results indicate that the use of back-flow valves can ensure the prevention of flow from the patient to the injector. Results also indicate that the use of sprung valves, those which require a significant forward pressure to open them, are more appropriate for this application.