“…Over recent years, sulfur hexafluoride (SF 6 ), tetrafluoromethane (CF 4 ), hexafluoroethane (C 2 F 6 ), perfluoropropane (C 3 F 8 ), and octafluorocyclobutane (C 4 F 8 ) have been used to investigate static ventilation 3,4 and diffusion, 5 gas wash‐in and wash‐out dynamics, 6–9 fractional ventilation, 10 ventilation/perfusion ratios, 11,12 as well as surface/volume ratios 13 in animal models, healthy volunteers, and patients with various lung diseases.…”