A radioactive method for assessing microbial safety of an infusion set for contrast-enhanced imaging

1185 Objectives Multiple uses of automatic contrast injection systems can save costs. However, cross-contaminations with blood-borne pathogens of infectious diseases may occur. We developed a radioactive method for quantitative safety evaluation on a new replaceable patient-delivery system. By mimicking pathogens with a radiotracer, we evaluated the feasibility of using the system repeatedly without septic risks. Methods Twelve patient-delivery systems were tested using an automatic contrast dual-injector and one filling-injecting set. Protocols with normal saline (n=6) and contrast agent plus saline (n=6) loaded in the injection system were compared. Each patient-delivery system was connected to the ear vein of a rabbit that was intravenously pre-injected with a radiotracer 99mTc-dimercaptopropionyl-human serum albumin (185MBq/rabbit). Aliquots from filling-injecting set, patient line and blood were counted after replacing each patient-delivery system. Results With saline, radioactivity was found in blood (1655903±593221 CPM) and in patient line (52894±33080 CPM) but in none of samples from the filling-injecting set (8±3 CPM), relative to the background (7±3 CPM) (p=0.726). Contrast plus saline showed radioactivity in blood (1119107±183174 CPM) and in patient line (32991±20232 CPM) but in none of samples from the filling-injecting set (6±6 CPM), relative to the background (6±4 CPM) (p=0.955). Conclusions This radioactive method appears accurate and reliable. The patient-delivery system proves safe and convenient. By replacing the patient delivery system, cross-contamination risks can be avoided without changing the main part of injection system. This method can be applied for evaluation of similar devices before human use. Animal experiments with radioactive techniques allow sensitive real-time analyses.