Transkull transmission of an intense focused ultrasonic beam

An intense focused ultrasonic beam was used in the transkull transmission mode to produce focal thermal “lesions” in a lucite block. This result was accomplished with a 1 MHz beam transmitted through an excised adult human skull section which had been shown by low intensity measurements to have 13 dB attenuation of sound pressure at this frequency. The essential focal beam dimensions and temporal coherence of the sound wave have been preserved at this frequency after transmission through this particular skull. Other studies indicate that no adult human skull should have a higher attenuation value at a frequency of 500 kHz than this skull shows at 1 MHz.