The process of blocking blood flow to a tumor is called embolization, and using gas bubbles is a new technique in embolotherapy. What makes it so promising is that the technique allows doctors to control exactly where the bubbles are formed, so blockage of blood flow to surrounding tissue is minimal, said Joseph Bull, assistant professor of biomedical engineering at U-M.
The research of Bull and collaborator Brian Fowlkes, an associate professor in the Department of Radiology in the U-M Medical School, is currently focused on the fundamental vaporization and transport topics that must first be understood in order to translate this developmental technique to the clinic.
In traditional embolotherapy techniques, the so-called cork that doctors use to block the blood flow---called an emboli---is solid. For instance, it could be a blood clot or a gel of some kind. A major difficulty with these approaches is restricting the emboli to the tumor to minimize destruction of surrounding tissue, without extremely invasive procedures, Bull said. The emboli must be delivered by a catheter placed into the body at the tumor site.
Gas bubbles, on the other hand, allow very precise delivery because their formation can be controlled and directed from the outside, by a focused high intensity ultrasound.
This envisioned technique is actually a two-step process, Bull said. First, a stream of encapsulated superheated perfluorocarbon liquid droplets goes into the body by way of an intravenous injection. The droplets are small enough that they don't lodge in vessels. Doctors image the droplets with standard ultrasound, and once the droplets reach their destination, scientists hit them with
Source:University of Michigan