Sulfur hexafluoride

Absorption

The pharmacokinetic of the SF6 gas component of Lumason was evaluated in 12 healthy adult subjects (7 men and 5 women). After intravenous bolus injections of 0.03 mL/kg and 0.3 mL/kg of Lumason, corresponding to approximately 1 and 10 times the recommended doses, concentrations of SF6 in blood peaked within 1 to 2 minutes for both doses.

Description

Sulfur hexafluoride is a colorless, odorless, nontoxic, nonflammable gas that has a high dielectric strength and serves widely as an insulating gas in electrical equipment. At atmospheric pressures it sublimes directly from the solid to the gas phase and does not have a stable liquid phase unless under a pressure of more than 32 psia (221 kPa, abs). It is shipped as a liquefied compressed gas at its vapor pressure of 298 psig at 70°F (2050 kPa at 21.1°C).
One of the most chemically inert gases known, it is completely stable in the presence of most materials to temperatures of about 400°F (204°C) and has shown no breakdown or reaction in quartz at 900°F (482°C). Sulfur hexafluoride is slightly soluble in water and oil. No change in pH occurs when distilled water is saturated with sulfur hexafluoride.

The Uses of Sulfur hexafluoride

Sulfur hexafluoride is used extensively as a gaseous dielectric in various kinds of electrical power equipment, such as switchgear, transformers, condensers, and circuit breakers. It has also been used as a dielectric at microwave frequencies and as an insulating medium for the power supplies of high-voltage machines.
Sulfur hexafluoride is also gaining use in nonelectrical applications, including blanketing of molten magnesium, leak detection, and plasma etching in the semiconductor industry. Sulfur hexafluoride also has some limited medical applications.

Background

Sulfur hexafluoride is an ultrasound contrast agent indicated for use ?in echocardiography to opacify the left ventricular chamber and to improve the delineation of the left ventricular endocardial border in adult patients with suboptimal echocardiograms ?in ultrasonography of the liver for characterization of focal liver lesions in adult and pediatric patients

Indications

Echocardiography: Sulfur hexafluoride is indicated for use in adult patients with suboptimal echocardiograms to opacify the left ventricular chamber and to improve the delineation of the left ventricularendocardial border. Ultrasonography of the Liver: Sulfur hexafluoride is indicated for use with ultrasound of the liver in adult and pediatric patients to characterize focal liver lesions.

Pharmacokinetics

Sulfur hexafluoride provides useful echocardiographic signal intensity for two minutes after the injection. Sulfur hexafluoride microspheres are destroyed and contrast enhancement decreases as the mechanical index increases (values of 0.8 or less are recommended). For ultrasonography of the liver, Sulfur hexafluoride provides dynamic patterns of differential signal intensity enhancement between focal liver lesions and liver parenchyma during the arterial, portal venous, and late phase of signal intensity enhancement of the microvasculature.

Metabolism

SF6 undergoes little or no biotransformation; 88% of an administered dose is recovered unchanged in expired air.