Piezoelectric transducer for the destruction of concretions within an animal body
AssigneeRichard Wolf GmbH
InventorsGunther Kurtze, Rainer Riedlinger
Life of this patent
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Abstract
A piezoelectric transducer in the form of a spheroidal cap comprises a mosaic of individual piezoceramic elements having a height of 3 to 10 mms and a lateral extension that does not substantially exceed the height there being gaps between the piezoceramic elements which are filled with an electrically insulating material having a modulus of elasticity which is smaller by at least one order of magnitude than that of the ceramic material, with the rise of the spheroidal cap amounting to at least 5 cms and the apex angle of the corresponding spherical sector amounting to at least 60.degree..
Claims21
A piezoelectric transducer for the destruction of hard concretions within an animal body, said piezoelectric transducer being in the form of a spheroidal cap with a rise and comprising a mosaic of separate piezoceramic elements each having a height of about 3 to about 10 mm and a lateral extension which does not substantially exceed the height, said piezoceramic elements having gaps therebetween, said gaps being filled with an electrically insulating elastic material having a modulus of elasticity which is smaller by at least one order of magnitude than that of the piezoceramic material, and the rise of the spheroidal cap being at least 5 cms and the apex angle of the corresponding spherical sector of the cap being at least 60.degree..
An apparatus according to claim 8 wherein the cap has a recess being filled with a soft plastic material to form a member having an acoustic impedance which is approximately equal to that of the body tissue and said member having a surface which is outwardly slightly domed convexly.
An apparatus for destroying hard concretions within an animal body, said apparatus including a piezoelectric transducer having a form of a spheroidal cap with a rise, said transducer comprising a mosaic of separate piezoceramic elements each having a height of a range of 3 to 10 mm and a lateral extension which does not substantially exceed the height, said piezoceramic elements having gaps therebetween, said gaps being filled with an electrically insulating elastic material having a modulus of elasticity which is smaller by at least one order of magnitude than that of the material of the elements, and the rise of the spheroidal cap being at least 5 cm and the apex angle of the corresponding spherical sector of the cap being at least 60.degree..
A method of using an apparatus having a piezoelectric transducer for the destruction of hard concretions within an animal body, said transducer having a form of spheroidal cap with a rise and comprising a mosaic of separate piezoceramic elements each having a height of a range of 3 10 mm and a lateral extension which does not substantially exceed the height, the piezoceramic elements having gaps therebetween which are filled with an electrically insulating elastic material having a modulus of elasticity which is smaller by at least one order of magnitude than that of the ceramic material of the elements and the rise of the spheroidal cap being at least 5 cm and the apex angle of the corresponding spherical sector being at least 60.degree., said method comprising creating individual pressure pulses of a duration of 1 .mu.s in the transducer to destroy the concretions by charging the transducer with a rise time <<1 .mu.s and a voltage of a range of 5-15 kV and then discharging the transducer with a decay period of >1 .mu.s.
A method of destroying calculi from outside of a patient's body, comprising the steps of:
- (a) fixing a plurality of individual piezoelectric elements, each having an inner end face, in a mosaic pattern on a support member, isolated from each other, so that each inner end face is substantially facing a common focal point over an included angle of at least sixty degrees and the inner end faces collectively define a generally spherical transmissive surface having a rise of at least five centimeters;
- (b) determining the position of a calculus inside the patient's body by directing low power ultrasonic pulse waves into the body and viewing an image derived therefrom on an image screen;
- (c) positioning said support member and transmissive surface outside the patient's body so that the focal point coincides with the determined position of said calculus inside the patient's body;
- (d) exciting each of said elements with at least one high power electrical signal so that at least one discrete pulse is generated from said transmissive surface and focused at said focal point and no greater than about ten pulses per second are generated;
- (e) transmitting said pulse through liquid interposed between said elements and the patients body to said focal point;
- (f) redetermining the position of said calculus by directing low power ultrasonic waves into the body and viewing an image derived therefrom on said image screen;
- (g) repositioning said arrangement if the position of the calculus has moved so that the focal point continues to coincide with the calculus;
- (h) repeating steps (d) through (g) above until clinically beneficial calculus destruction has been achieved;
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- (i) at all times maintaining the pulse rate over time and the pulse power per pulse at levels which, in total, destroy the calculus without clinically significant injury to tissue.
A lithotrite for contact-free, pulsed wave disintegration of calculi without producing clinically significant injury to tissue without an animal body, comprising;
- (a) a high power, ultrasonic pulse generator;
- (b) a piezoelectric transducer formed by a mosaic of piezoelectric elements separated from each other by gaps and mounted on a rear member so as to form a spherical transmissive surface portion adapted to focus the disintegrating waves at a focal spot spaced from the transmissive surface portion;
- and
- (c) means substantially enclosing said spherical transmissive surface portion and said gaps;
- (d) said enclosing means and said gaps containing insulating material, and said enclosing means including two flexible diaphragms having a fluid therebetween;
- (e) one of said diaphragms permitting coupling to the skin of the animal's body.
Dependencies are inferred from the claim text.