8/3/2014 · Objective We developed a bubble point test kit and investigated the bubble point test of a 0.22-μm membrane filter used for the sterilizing filtration of [18F]FDG, [11C]MET and [11C]PIB. The bubble point test of the Millex-GS vented filter was often difficult due to air leakage from the vented portion of this filter. Therefore, to close the vented portion of this filter simply and reliably