A new ultrasound device, used in conjunction with magnetic resonance imaging (MRI), allows neurosurgeons to precisely burn out small pieces of malfunctioning brain tissue without cutting the skin or opening the skull. A preliminary study from Switzerland involving nine patients with chronic pain shows that the technology can be used safely in humans. The researchers now aim to test it in patients with other disorders, such as Parkinson’s disease
“The groundbreaking finding here is that you can make lesions deep in the brain–through the intact skull and skin–with extreme precision and accuracy and safety,” says Neal Kassell, a neurosurgeon at the University of Virginia. Kassell, who was not directly involved in the study, is chairman of the Focused Ultrasound Surgery Foundation, a nonprofit based in Charlottesville, VA, that was founded to develop new applications for focused ultrasound.
High-intensity focused ultrasound (HIFU) is different from the ultrasound used for diagnostic purposes, such as prenatal screening. Using a specialized device, high-intensity ultrasound beams are focused onto a small piece of diseased tissue, heating it up and destroying it. The technology is currently used to ablate uterine fibroids–small benign tumors in the uterus–and it’s in clinical testing for removing tumors from breast and other cancers. Now InSightec, an ultrasound technology company headquartered in Israel, has developed an experimental HIFU device designed to target the brain.
The major challenge in using ultrasound in the brain is figuring out how to focus the beams through the skull, which absorbs energy from the sound waves and distorts their path. The InSightec device consists of an array of more than 1,000 ultrasound transducers, each of which can be individually focused. “You take a CT scan of the patient’s head and tailor the acoustic beam to focus through the skull,” says Eyal Zadicario, head of InSightec’s neurology program. The device also has a built-in cooling system to prevent the skull from overheating.
The ultrasound beams are focused on a specific point in the brain–the exact location depends on the condition being treated–that absorbs the energy and converts it to heat. This raises the temperature to about 130 degrees Fahrenheit and kills the cells in a region approximately 10 cubic millimeters in volume. The entire system is integrated with a magnetic resonance scanner, which allows neurosurgeons to make sure they target the correct piece of brain tissue. “Thermal images acquired in real time during the treatment allow the surgeon to see where and to what extent the rise in temperature is achieved,” says Zadicario.
Just be careful in there. Too bad they can’t selectively numb the cells to see if the effect is positive or negative. Wow, imagine the ability to stimulate one or two neurons at a time with this. You might be able to evoke specific memories… and then wipe them out?
Woody Allen Quote:
“My brain? That’s my second favorite organ.”