Embolization is the selective blocking of blood vessels by placing tiny particles in the vessel. Once the particles in place, the blood flow along that vessel is dimished or stopped entirely. Embolization is used for many purposes, such as cutting off the blood supply to malignant tumors or uterine fibroids, or to stop hemorrhaging in the lungs or nasal passages.

The particles are about the size of a grain of sand, and they are made of a plastic substance that is similar to the material used to make hard contact lenses, called polyvinyl alcohol (PVA).  This is a medical-grade material that is FDA approved for embolization and has been used for embolization in the human body for over 20 years.

Embolization is a catheter-based procedure. The catheter is guided via fluoroscopy (live x-ray) to the location to be blocked. The particles are released until the blood flow has been reduced to the appropriate level. The catheter is withdrawn and the procedure is done.