Failure of 18F-florbetapir Amyloid PET Imaging after Injection With an Automated Injector Using an Air-vent Filter for FDG Injection

A 77-year-old woman with mild cognitive impairment was referred to 18F-florbetapir positron emission tomography (PET) to assess the indication of a disease-modifying drug against Alzheimer disease. PET images showed no uptake in the brain and only slight uptake in the sinus veins. In an automated injector, almost all the radioactivity was trapped in an air-vent filter, which is usually used for FDG injections and is made of mixed cellulose ester. After injection using other types of filters not made of mixed cellulose ester, 18F-florbetapir PET imaging was successful. The filter made of mixed cellulose ester should never be used for 18F-florbetapir injection.