Method and apparatus for enhancing the reflection coefficient of a surgical instrument for use in conjunction with an apparatus for pulse-echo ultrasound imaging of an area of the body, by means of a diffraction grating disposed on the surgical instrument.

An ultrasonic medical apparatus, particularly convenient for use inside a body cavity, includes an applicator having an ultrasonic transducer, which may be attached to an acoustic lens such that the emitted ultrasonic waves are focused at two or more different positions. For this purpose, the wave-emitting surface of the transducer, or the acoustic lens attached to it, is partitioned into concave surface elements which may be in a concentric annular arrangement and may each have a different radius of curvature and a different center of concavity. An apparatus thus structured can be made compact and hence is convenient for use inside a body cavity.

The present invention relates to an ultrasound visualization system which has a capability of microscopic examination of tissue within the body without the need for removal of the tissue. A transducer, capable of producing and receiving high frequency acoustical beams is positioned within a needle. The acoustical beams are directed radially from the needle and are focused on a point which is outside of the needle and in the tissue. The microscope can be operated in either the pulse echo or pulse reflection mode. The needle can be inserted into a patient, and the acoustical beams are scanned to produce highly magnified images of cellular features of internal tissue or features of tissue architecture and structure helpful to the determination of tissue pathology.

Disclosed is an apparatus for the treatment of biological tissue as well as for destroying concretions by means of focussed acoustic waves, having a sound generating unit which a control unit triggers in such a manner that the unit generates acoustic waves of a specific frequency and energy, and a focussing unit which focusses the generated waves in a focal area. The present invention is distinguished by the sound generating unit (2) being provided, in an as such known manner, with a plane or only slightly curved radiation area in such a manner that the generated wave is an essentially plane wave and that the focussing unit (5) disposed in a fixed spatial relationship to the sound generating unit being provided with a Fresnel lenslike structure on the sound entry and/or sound exit area.

In a hyperthermia apparatus, ultrasonic waves obtained by using an ultrasonic vibrator are focused in a living body through an acoustic lens and degassed water to form a heating region. In this case, the ultrasonic vibrator is not required to be divided, and the surface of the acoustic lens in contact with the ultrasonic vibrator and the opposite surface are formed in a concave surface, and hills and valleys spreading alternatively in the radial direction are formed on thik concave surface, and the portion between these hill and valley are formed in a plane or a curved surface. In accordance with this acoustic lens, the ultrasonic waves are focused on the heating region, and a phase difference is produced by a difference in thickness between the hill part and the valley part, and thereby no undesirable hot spots are produced behind the heating region.