this invention relates to the filling or dispensing of radiopharmaceuticals in sample vials . radiopharmaceuticals must be dispensed in a cleanroom environment according to cgmp regulations . single - use filling cassette - type dispensing systems can be used for filling or dispensing of radiopharmaceuticals in sample vials . a single - use filling cassette is the core of such a dispenser system . a flexible bag container comprising a flexible bag and a filling cassette was found . the filling cassette is assembled within the flexible bag under aseptic conditions . the assembled filling cassette defined a closed system since each opening is connected to a sample vials or sterile filter avoiding contamination from outside .