Image guidance and beam localization for transcranial focused ultrasound therapy

Therapeutic uses of transcranial focused ultrasound (tFUS) in the brain are being widely explored in both clinical and research settings from tissue destruction to blood brain barrier opening (BBBO) to neuromodulation. The appeal of tFUS is the ability to target structures throughout the brain with a millimeter scale focus. In order to understand the outcome of the treatment or experiment it is important to ensure the tFUS beam is targeted to and located at the region of interest. Image guidance allows for targeting of anatomical or functional structures within the brain. Here we present a targeting and localization scheme where optical tracking of the transducer is used to target the tFUS focus to a brain region within a previously acquired image and MR acoustic radiation force imaging is used to localize the beam in the brain to ensure the focus is at the target. By combining this targeting and localization scheme with a phased array transducer we are able to then steer the focus to ensure accurate sonications of specific brain regions using tFUS. This talk will discuss the application of this method to two different phased array transducers used for neuromodulation and BBBO in nonhuman primates.