Non-invasive Transcranial Surgery with Dual-Mode Ultrasound Arrays

We present the first transcranial mapping of temperature with Dual-Mode Ultrasound Arrays (DMUAs), with subsequent validation of transskull ultrasound therapy guidance and monitoring in a small rodent model. Experiments were conducted in sacrificed rats, utilizing the custom designed DMUA platform manufactured in our laboratory. First, careful examination of DMUA imaging through the skull was conducted, where a fine 50 mu m wire was embedded within the brain tissue. Second, anatomical landmarks were visualized by co-registering two volumes, volume of synthetic aperture (SA) images acquired with DMUA and a 9.4T MRI volume acquired in live rats prior to the sacrifice. Third, subtherapeutic shot delivery through the skull was tested, where a set of five varying intensity shots were deposited below the skull surface. Shot delivery and temperature monitoring were performed with DMUA, and compared with the thermocouple data acquired close to the therapeutic focus. This study was an exploratory effort to validate ultrasound therapy delivery and monitoring in transcranial applications with DMUAs. In conclusion, DMUAs offer a unique advantage by providing real-time feedback by means of temperature monitoring with a high degree of spatial localization.