Medicinal gases

Nitrous oxide and oxygen have been used for more than 100 years. Other gases, such as helium, are used in sophisticated techniques such as MRI (magnetic resonance imaging), keyhole surgery and PET (positron emission tomography). Carbon dioxide is employed in bath therapy and for cryo surgery, liquid nitrogen is used for cryo surgery, rheumatic therapy and cryo conservation and nitric oxide for patients with pulmonary failure.