Georg Naser

Shockwave source having a centrally disposed ultrasound locating system

A shockwave source of the type wherein a shockwave is generated by rapid electromagnetic repulsion of a membrane by a rapidly energized coil has a central opening extending through the membrane and the coil. An ultrasound head of an ultrasound transmission and reception system is received in the opening. The ultrasound head is disposed in a mount which is rotatable around its longitudinal axis by a rotary drive. In one embodiment of the shockwave source, the shockwave source also has a focusing device disposed in front of the membrane, and in this embodiment the focusing device also has a central opening in which the ultrasound head is received. The ultrasound head has a distal end in contact with a liquid coupling agent for promoting transmission to, and reception from, a patient to which the shockwave source is coupled. The shockwave source is particularly suited for lithotripsy treatment of gallstones.

Lithotripter comprising locating apparatus

A lithotripter for treating calculi has a housing formed by a first sub-housing with an opening with a membrane for contacting the patient, a second sub-housing composed of two parts with the first of the two parts forming a cylindrical bearing with the first sub-housing to allow rotation around an axis, a second part being mounted for pivotal movement on an axis extending perpendicular to the axis of rotation. The second housing part supports the source of the shockwave to create a shockwave on a central axis and includes a focussing arrangement mounted on the second part for focussing the shockwave on the central axis. To locate the calculus or stone, two scanning heads having sector scanning planes are mounted at a predetermined angle on the focus arrangement. To locate the stone, the second housing part is rotated to locate the stone in one of the scan planes, and then the second housing part is pivoted to move the second scan plane onto the stone.

Extracorporeal shock wave source with a piezoelectric generator

An extracorporeal lithotripter with a piezoceramic pressure source which emits focused pressure waves focussed at a point within a patient at which a calculus to be disintegrated is located. A number of discrete piezoceramic elements are arranged along a curve forming an ultrasound resonator having a diameter of at least about 10 cm and a radius of curvature up to about 20 cm, and operated at an ultrasound frequency below about 500 kHz. The volume between the ultrasound resonator and a terminating membrane through which the pressure waves pass is filled with a A having an acoustic impedance higher than water, preferably greater than or equal to the acoustic impedance of ethylene glycol, so that the piezoceramic elements, forming the pressure source, can be disposed closer to the focus, thereby reducing losses due to non-linear attenuation. The overall efficiency of the lithotripter is thereby increased, and the load of acoustical energy on the patient is diminished. A coupling member may be disposed between the terminating membrane and the patient.

Ultra-sound sensor

The ultrasound sensor (2) of the invention comprises a polymer foil (4) which is supported in its outer region and is piezoelectrically activated at least in one portion (42). The portion (42) is coupled electrically to a first electrode (200) in the form of an adjacent, i.e., touching pin. A second electrode (8), in the form of a grid (214) connected to ground and/or a ring (216) connected to ground, is physically separated from the activated portion (42). The pin (200) is connected to the first input of an amplifier (210). The second input thereof is connected to ground. The metallic take-off at the activated zone (42) results in high sensitivity of the ultra-sound sensor (2) which is provided particularly for the measurement of shock waves with a high pressure amplitude and which finds application in lithotripsy.

Shock wave generator for generating an acoustical shock wave pulse

A shock wave generator has a focusing stage wherein a number of different lenses having respectively different concentrating characteristics are accommodated, and which can be selectively introduced transversely into the path of the shock wave pulse, by linear displacement or by pivoting. The lenses can be alternatively introduced one at a time in one embodiment, or in a second embodiment more than one lens can be simultaneously introduced to achieve a concentrating characteristic resulting from a combination of lenses. For further adjustment and flexibility, the shock wave generator is provided with at least two capacitors for selectively varying the amount of discharge energy used to trigger the shock wave. The approach path between the membrane which generates the shock wave and the lens can also be varied. By combining variations in the discharge energy, the length of the approach path, and the type of lens, a wide range of operating conditions are available so that operation of the shock wave generator can be adapted from patient to patient in accord with the best suited treatment.

Shock wave source with increased degree of effectiveness

A shock wave source, especially useful for a lithotriptor, has a pressure source for the generation of a pressure wave impulse, a focusing device for focusing the pressure wave pulse, and a seal diaphragm for coupling the pressure wave pulse into the body of a patient, perhaps via a coupling body placed between the seal diaphragm and the patient. The seal diaphragm and the focusing device of the pressure source form a space which serves as a prepassage. The prepassage space is filled with a liquid substance which has a high B/A ratio and an acoustic impedance less than or equal to that of water. The advantage of this configuration is that the pressure wave pulse can be built up very rapidly in its course through the space. At a given point in the space, with the selection of the above-mentioned substances, as compared to water, a given minimum value of the quotient amplitude/build-up time of the pressure wave pulse can be achieved inspite of a reduced output amplitude at the pressure source. Consequently, the life expectancy of the pressure source is higher and less stress is placed on the patient by the acoustic energy. Thus, the degree of effectiveness of the lithotriptor is increased.

Sensor for evaluation of shock wave pulses

A sensor for determining the position of shock wave pulses of a shock wave source comprises a device for holding a metal foil in the region of focus for the shock wave source. The metal foil is held to extend perpendicular to the main propagation direction of the pulses and the incidence of the pulses on the metal foil will cause a bulge-like deformation of the material to be formed at the point of incidence. The deformation in the foil can be optically measured, for example, by evaluation in terms of location, diameter, depth, profile and volume to obtain conclusions about the position of the center of the focussed shock waves and also the power or intensity of the shock waves.