Mario Bechtold

A linear phased array for prostate therapy

A linear phased array for thermotherapy of the prostate with rectal access has been developed. The curved transducer elements with a radius of curvature of 56 mm provide a prefocus in a first plane at a distance of 10 mm in the tissue. The 125 transducer elements can be steered to scan the tumor area in the other plane, while the first plane is being scanned by rotation of the array around its axis. The transmission efficiency of the transducer elements is 47% at 1.7 MHz with a -3 dB bandwidth of 100 kHz due to single matching layer and air backing. The low electrical cross-coupling (-30 dB) enables broad angle single element transmission with a -3 dB angle of more than 50/spl deg/. A simulation program incorporating the elements curvature and different fluids demonstrates the array electronic focusing property in one plane in conjunction with the mechanical prefocus in the other plane.

Ultrasound transmitting configuration

An ultrasound transmitting configuration includes at least one ultrasound generating device for exposing a medium which has an acoustic medium impedance and a medium speed of sound to ultrasonic waves. The ultrasound generating device has at least two ultrasound transducers which can be excited through actuating electrodes for emitting ultrasound and which have an acoustic transducer impedance. The ultrasound transducers are separated from one another and disposed alongside one another. An ultrasound lens which has an acoustic lens impedance and a lens speed of sound is disposed between the ultrasound generating device and the medium. The ultrasound generating device is acoustically coupled on a coupling side to the ultrasound lens. The ultrasound transducers extend toward the medium over a transducer depth, they extend toward one another over a transducer width, and they extend at right angles to both the transducer depth and the transducer width over a transducer length. The transducer width is maximally as great as the transducer depth, and the transducer length is considerably greater than the transducer depth. The ultrasound transducers are associated with a common actuating element for actuating the ultrasound transducers jointly and in the same way.