Your search for "radiometric mass flowmeters" revealed the following:

Endress+Hauser CNGmass D8CB CNG Coriolis flowmeter for high-pressure natural gas refueling
Endress+Hauser LPGmass D8EB LPG Coriolis flowmeter for refueling and distribution applications
Endress+Hauser Proline Prowirl R 200 low-flow vortex flowmeter for steam and gas measurement
Fluke 922 Airflow Meter/Micromanometer for HVAC airflow measurement
Fluke 922 HVAC airflow meter for differential pressure and air velocity testing
Endress+Hauser Proline Prowirl O 200 high-pressure vortex flowmeter for steam and gas measurement