Using Ultrasound to Treat Brain Tumors

Researchers are studying the feasibility of using high-intensity focused ultrasound (HIFU) as a noninvasive way to treat brain tumors.

HIFU generates ultrasonic waves at an intensity several orders of magnitude higher than those utilized in medical imaging. The waves are focused much in the same manner as those used in medical imaging. HIFU can be made to accurately kill cells by producing heat, but it can do so without killing cells outside the focused area.

"You want to ‘cook' only the tumor and not the surrounding cells,” said Dr. Viren Amin, leader of the study and a scientist at the Center for Nondestructive Evaluation at Iowa State University (Ames, IA, USA) and an adjunct professor of electrical and computer engineering.

There are obstacles to overcome before the ultrasound technology can be used to destroy brain tumors. "We need to predict what the ultrasound beam will do when it goes through so many layers of tissue,” said Dr. Amin. This tissue "inhomogeniety” causes ultrasound energy to be localized in hot spots. The researchers have devised computational models for ultrasound transmission through inhomogeneous materials. Dr. Amin reported that these data can be applied to medical applications to develop high-precision ultrasound therapy.

Another challenge is calculating and delivering the therapy dose--the frequency, intensity, and focus--for a certain type of tumor and location. The scientists will develop visualization and imaging tools to incorporate magnetic resonance imaging (MRI) and ultrasound images as well as simulations of ultrasound beams through tissues and of the heat generated at the focus. These tools will be used to aid in planning high-intensity focused ultrasound treatments. "It's a true multidisciplinary project,” said Dr. Amin.




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