Abstract: A system and method for controlling the delivery of ultrasound energy to a subject is provided. In particular, such a system and method are capable of safely disrupting the blood-brain barrier. Ultrasound energy is delivered to produce cavitation of an ultrasound contrast agent at a selected pressure value. An acoustic signal is acquired following cavitation, from which a signal spectrum is produced. The signal spectrum is analyzed for the presence of harmonics, such as subharmonics or ultraharmonics. When subharmonics or ultraharmonics are present, the pressure value is decreased for subsequent sonications. If a previous sonication resulted in no subharmonics or ultraharmonics being generated, then the pressure value may be increased. In this manner, the blood-brain barrier can be advantageously disrupted while mitigating potentially injurious effects of the sonication.

Abstract: A system and method for controlling the delivery of ultrasound energy to a subject is provided. In particular, such a system and method are capable of safely disrupting the blood-brain barrier. Ultrasound energy is delivered to produce cavitation of an ultrasound contrast agent at a selected pressure value. An acoustic signal is acquired following cavitation, from which a signal spectrum is produced. The signal spectrum is analyzed for the presence of harmonics, such as subharmonics or ultraharmonics. When subharmonics or ultraharmonics are present, the pressure value is decreased for subsequent sonications. If a previous sonication resulted in no subharmonics or ultraharmonics being generated, then the pressure value may be increased. In this manner, the blood-brain barrier can be advantageously disrupted while mitigating potentially injurious effects of the sonication.

Abstract: A system and method for efficiently transmitting and receiving focused ultrasound through a medium, such as bone, is provided. The focal region of the focused ultrasound is iteratively updated to provide an improved focus through the medium. This method may be carried out using a transducer assembly that includes two or more transmit arrays each operating at a different frequency. An initial focus is set and updated by delivering focused ultrasound with a lower frequency transmit array. The phase corrections determined in the first iteration are applied to subsequently higher frequency transmit arrays and received signals, and the process repeated until a desired focus or image resolution is achieved.

Abstract: A system and method for controlling the delivery of ultrasound energy to a subject is provided. In particular, such a system and method are capable of safely disrupting the blood-brain barrier. Ultrasound energy is delivered to produce cavitation of an ultrasound contrast agent at a selected pressure value. An acoustic signal is acquired following cavitation, from which a signal spectrum is produced. The signal spectrum is analyzed for the presence of harmonics, such as subharmonics or ultraharmonics. When subharmonics or ultraharmonics are present, the pressure value is decreased for subsequent sonications. If a previous sonication resulted in no subharmonics or ultraharmonics being generated, then the pressure value may be increased. In this manner, the blood-brain barrier can be advantageously disrupted while mitigating potentially injurious effects of the sonication.

Abstract: A system and method for controlling the delivery of ultrasound energy to a subject is provided. In particular, such a system and method are capable of safely disrupting the blood-brain barrier. Ultrasound energy is delivered to produce cavitation of an ultrasound contrast agent at a selected pressure value. An acoustic signal is acquired following cavitation, from which a signal spectrum is produced. The signal spectrum is analyzed for the presence of harmonics, such as subharmonics or ultraharmonics. When subharmonics or ultraharmonics are present, the pressure value is decreased for subsequent sonications. If a previous sonication resulted in no subharmonics or ultraharmonics being generated, then the pressure value may be increased. In this manner, the blood-brain barrier can be advantageously disrupted while mitigating potentially injurious effects of the sonication.

Abstract: A system and method for controlling the delivery of ultrasound energy to a subject is provided. In particular, such a system and method are capable of safely disrupting the blood-brain barrier. Ultrasound energy is delivered to produce cavitation of an ultrasound contrast agent at a selected pressure value. An acoustic signal is acquired following cavitation, from which a signal spectrum is produced. The signal spectrum is analyzed for the presence of harmonics, such as subharmonics or ultraharmonics. When subharmonics or ultraharmonics are present, the pressure value is decreased for subsequent sonications. If a previous sonication resulted in no subharmonics or ultraharmonics being generated, then the pressure value may be increased. In this manner, the blood-brain barrier can be advantageously disrupted while mitigating potentially injurious effects of the sonication.

Abstract: A system and method for efficiently transmitting and receiving focused ultrasound through a medium, such as bone, is provided. The focal region of the focused ultrasound is iteratively updated to provide an improved focus through the medium. This method may be carried out using a transducer assembly that includes two or more transmit arrays each operating at a different frequency. An initial focus is set and updated by delivering focused ultrasound with a lower frequency transmit array. The phase corrections determined in the first iteration are applied to subsequently higher frequency transmit arrays and received signals, and the process repeated until a desired focus or image resolution is achieved.

Abstract: A system and method for controlling the delivery of ultrasound energy to a subject is provided. In particular, such a system and method are capable of safely disrupting the blood-brain barrier. Ultrasound energy is delivered to produce cavitation of an ultrasound contrast agent at a selected pressure value. An acoustic signal is acquired following cavitation, from which a signal spectrum is produced. The signal spectrum is analyzed for the presence of harmonics, such as subharmonics or ultraharmonics. When subharmonics or ultraharmonics are present, the pressure value is decreased for subsequent sonications. If a previous sonication resulted in no subharmonics or ultraharmonics being generated, then the pressure value may be increased. In this manner, the blood-brain barrier can be advantageously disrupted while mitigating potentially injurious effects of the sonication.