New Imaging Methods Improve Focused Ultrasound Brain Treatments


Key Points

  • Researchers are continually working to improve, refine, and expand the use of focused ultrasound technology.
  • Researchers at Stanford University investigated focus correction across the skull.
  • An improved technique, the hybrid angular spectrum method, achieved better results than the standard of care in three important areas.

Transcranial Focused Ultrasound Phase Correction Using the Hybrid Angular Spectrum Method

Although focused ultrasound is successfully being used for thousands of brain treatments around the world, scientists are continually working to improve, refine, and expand the technology. A research team based at Stanford University in collaboration with Focused Ultrasound Foundation team members investigated, calculated, and compared various methods for overcoming the blurring of focused ultrasound treatment by the skull. An improved technique, the hybrid angular spectrum method, achieved significantly better results than the current standard of care for target intensity, peak intensity, and positioning error.

“For the same energy input, a higher temperature at the focus can be achieved,” said John Snell, PhD, the Technical Director of the Foundation’s Brain Program and co-author of the paper. “This means that additional targets in the brain can be reached, and a larger population of patients would be suitable candidates for treatment.”

The ex vivo study tested three human skulls and calculated phase corrections using four different methods [straight ray tracing, the commercial standard ray tracing method, the hybrid angular spectrum (HAS) method, and hydrophone]. Incorporating the HAS method into the current clinical system may improve treatment outcomes, specifically benefitting ablative techniques that require a high, focused power at the target. It could also improve the development of focused ultrasound neuromodulation and blood-brain barrier opening.

Dr. Snell added, “The HAS method is a much more complete simulation method, so it takes longer to compute than the method that is currently used by the Insightec system – but its computation time of about 30 minutes still produces results that could provide clinical utility. Continuous increases in speed and decreases in the cost of computational hardware are quickly making sophisticated acoustic simulations such as the HAS method practical for clinical use. This study is an important benchmark of where the technology currently stands.”

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