EP0461287B1 - Electrically-driven acoustic shock-wave generator - Google Patents

Electrically-driven acoustic shock-wave generator Download PDF

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Publication number
EP0461287B1
EP0461287B1 EP90111220A EP90111220A EP0461287B1 EP 0461287 B1 EP0461287 B1 EP 0461287B1 EP 90111220 A EP90111220 A EP 90111220A EP 90111220 A EP90111220 A EP 90111220A EP 0461287 B1 EP0461287 B1 EP 0461287B1
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EP
European Patent Office
Prior art keywords
membrane
generator according
coil arrangement
coolant
coil
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Expired - Lifetime
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EP90111220A
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German (de)
French (fr)
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EP0461287A1 (en
Inventor
Benedikt Dipl.-Ing. Hartinger (Fh)
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Siemens AG
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Siemens AG
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Priority to EP90111220A priority Critical patent/EP0461287B1/en
Priority to DE59005639T priority patent/DE59005639D1/en
Priority to US07/707,673 priority patent/US5165388A/en
Publication of EP0461287A1 publication Critical patent/EP0461287A1/en
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Publication of EP0461287B1 publication Critical patent/EP0461287B1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/06—Coils, e.g. winding, insulating, terminating or casing arrangements therefor
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
    • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated

Definitions

  • the invention relates to an electrically drivable acoustic shock wave generator which has, as electrically conductive elements, a coil arrangement and a membrane which can be driven in an electric shock-like manner by means of the coil arrangement, by means of which shock waves can be introduced into an acoustic propagation medium adjacent to the membrane.
  • shock wave generators can be used for a wide variety of purposes, e.g. in medicine to non-invasively break up the stones in a patient's body or to treat non-invasive pathological tissue changes.
  • shock wave generators can be used in material testing to apply shock waves to material samples.
  • the shock wave generator is always acoustically coupled in a suitable manner to the object to be irradiated, so that the shock waves generated in the acoustic propagation medium can be introduced into the object.
  • the shock wave generator and the object to be sonicated must be aligned so that the area of the object to be sonicated is in the path of propagation of the shock waves. If the shock wave generator emits focused shock waves, it must also be ensured that the area of the object to be irradiated is in the focus area of the shock waves.
  • shock wave generators For such shock wave generators it is approximately the case that the peak pressure of the shock waves which can be achieved increases with the square of the current flowing through the coil arrangement.
  • the coil arrangement with high-voltage pulses in the order of 10 to 20 kV must be applied in order to produce currents in the coil arrangement, the level of which is sufficient to generate shock waves which, after suitable focusing, can be used for Shattering of concrements in the body of living beings have the required peak pressure.
  • the necessity of having to apply voltages of the stated height to the coil arrangement is considered to be extremely disadvantageous in practice, since the insulation measures required to achieve a sufficient electrical strength of the shock wave generator are problematic and very complex.
  • the high voltages mentioned have a disadvantageous effect on the service life of not only the shock wave generator but also the electrical and electromechanical components of the high-voltage generator device provided for driving the shock wave generator.
  • the invention is therefore based on the object of designing a shock wave generator of the type mentioned in such a way that a relatively high peak pressure of the shock waves can be achieved even when the coil arrangement is subjected to comparatively low voltage.
  • this object is achieved in that at least one of the electrically conductive elements, that is to say the coil arrangement and / or membrane, contains material which can be set into the superconducting state and that means for setting the material containing the at least one electrically conductive element into the superconducting state are provided.
  • the ohmic resistance component of the coil arrangement practically completely disappears and / or higher currents are induced in the membrane as a result of superconductivity, in comparison with the prior art, electrical impulses of a lower voltage are sufficient in the shock wave generator according to the invention to reduce a specific current to let the coil assembly flow.
  • a variant of the invention provides that the coil arrangement can be brought into the superconducting state by means of a cooling medium, which is located in the region of the coil arrangement. Since the coil arrangement generally has to be fixed to a coil carrier, there is the advantageous possibility of providing the coil carrier with a channel through which the cooling medium flows past the coil arrangement as closely as possible. According to a preferred variant of the invention, however, it is provided that the coil arrangement is wound from a tube into material that can be brought into the superconducting state and that the cooling medium flows through the tube. That way it is special with low design effort possible to put the coil arrangement in the superconducting state, since a special channel system or the like is not required to bring the cooling medium to the coil arrangement.
  • a further particularly preferred embodiment of the invention provides that a coolant which brings the membrane into the superconducting state and is accommodated in a space upstream of the membrane is provided as the acoustic propagation medium.
  • the coolant that serves to put the membrane in the superconducting state is also used as an acoustic propagation medium for the shock waves, so that no additional design effort is required to be able to put the membrane in the superconducting state .
  • the coolant-receiving space is closed at its end remote from the membrane with a solid plate, which is formed from shock wave conductive material, ie a material with low acoustic damping for shock waves, and that side of the solid plate facing away from the membrane adjoins a second space in which there is a medium which conducts shock waves and whose temperature is higher than that of the coolant.
  • the membrane is formed from such a material that very low temperatures, ie temperatures well below 170 Kelvin, are required to achieve the superconducting state, since then, when viewed from the membrane, it is "tolerable” beyond the solid plate Temperatures ", for example in the order of the usual room temperature, can be achieved.
  • the heat flow from the medium conducting the shock waves through the solid plate into the coolant can be influenced, since the greater the thickness of the solid plate, the smaller the heat flow.
  • the cooling medium the channel or the tube forming the coil arrangement and / or the coolant the space upstream of the membrane and / or the shock wave conducting medium flows through the second space.
  • a partition wall made of shock wave-conducting material which closes the second room at its end remote from the solid plate, the one facing away from the second room Side of the partition is bordered by a material whose acoustic impedance corresponds essentially to that of an object to be irradiated.
  • the partition is designed as an acoustic lens.
  • the required design effort can be reduced considerably.
  • the changes in the refractive index of the lens material caused by a possibly existing temperature gradient of the lens material transverse to the direction of propagation of the shock waves can be taken into account.
  • One embodiment of the invention provides that a flexible sack is provided for acoustically coupling the shock wave generator to a living being to be sonicated, and that a shock wave conducting material adjoins the inside of the bellows, the temperature of which does not differ significantly from the body temperature of the living being.
  • the material adjacent to the bellows may be the coolant in the space upstream of the membrane, or the medium in the second space the one facing away from the second room Act on the side of the partition adjacent fabric or a special material.
  • the acoustic impedances of the substances in the propagation path of the shock waves should differ as little as possible from the acoustic impedance of the object to be irradiated in order to avoid losses due to reflections as far as possible.
  • FIG. 1 shows a shock wave generator which serves to break up concrements and has a tubular housing 1 which is closed at one end by a shock wave source, generally designated 2, and at the other end by a flexible bag 3.
  • the shock wave source 2 has a coil 5 arranged on a flat contact surface of a coil carrier 4. This has the connections 6 and 7, the turns of the coil 5 connecting the connections 6 and 7, one of the turns being provided with the reference symbol 8, running in a spiral.
  • the coil carrier 4 is formed from an electrically insulating material, for example aluminum oxide ceramic.
  • the space between the turns 8 of the coil 5 is filled with an electrically insulating casting resin, for example araldite (registered trademark).
  • the coil 5 consists of a material which can be put into the superconducting state, for example yttrium-barium-copper oxide, which remains superconducting up to temperatures of approximately 90 Kelvin.
  • a spiral groove 9 is embedded in the coil carrier 4, which is sealed liquid-tight with a disk 10, which is made of the same material as the coil carrier 4, so that an inlet 11 with the outlet 12 connecting channel is present.
  • the inlet line 13 and the outlet line 14 are connected to this.
  • liquid nitrogen With the help of a pump 15, liquid nitrogen, the temperature of 77 Kelvin is easily sufficient to bring the material of the coil 5 into the superconducting state, is pumped through the channel as a cooling medium.
  • a cooling unit 16 is provided in order to be able to ensure that the nitrogen remains in its liquid state.
  • the connections 6 and 7 of the coil 5 are connected to an electrical pulse generator 17.
  • a disc-shaped, flat membrane 19 is arranged opposite the side of the coil 5 facing away from the coil carrier 4, which also consists of a material that can be put into the superconducting state, for example barium-lanthanum-copper oxide.
  • the membrane 19, the insulating film 18 and the coil 5 are combined with the coil carrier 4 and the disk 10 by means of a centering edge attached to the coil carrier 4 to form a unit.
  • This unit is pressed against a shoulder 21 provided in the bore of the housing 1 by means of a ring 20 and a plurality of screws resting on the coil carrier 4 and several screws; only the center lines of two screws are indicated by dash-dotted lines.
  • the membrane 19 possibly with the interposition of suitable sealants, not shown, bears against the shoulder 21 in a liquid-tight manner.
  • a solid plate 22 which is made of a material with low thermal conductivity, for example polystyrene, in a liquid-tight manner.
  • liquid nitrogen In the space between the solid plate 22 and the membrane 19 there is liquid nitrogen, the presence of which causes the membrane 19 to be brought into the superconducting state.
  • the limited by the membrane 19 and the solid plate 22 Room has an inlet 23 and an outlet 24, to which an inlet line 25 and an outlet line 26 are connected, so that the liquid nitrogen can be circulated as a coolant by means of a pump 27, again with a cooling unit 28, so that it is ensured that the nitrogen maintains its liquid state.
  • a plane-concave acoustic converging lens 30 is fixed, which consists, for example, of polystyrene.
  • Glycerin for example, is possible as a liquid, whose acoustic impedance is similar to that of polystyrene.
  • the liquid located between the collecting lens 30 and the solid plate 22 is fed via inlet and outlet lines 33 and / or outlet lines 33 connected to an inlet 31 and an outlet 32. 34 with the help of a pump 35 through a heater 36, which compensates for the heat loss and ensures a constant temperature of the liquid in a manner known per se by means of thermostatic control.
  • the space between the collecting lens 30 and the sack 3 is filled with another liquid substance, for example water, the acoustic impedance of which is matched as precisely as possible to that of the tissue of the living being to be treated.
  • the further liquid substance which is circulated by means of a pump 41 via an inlet 37 and an outlet 38 and the inlet and outlet lines 39 and 40 connected to them, is kept at a temperature by means of a thermostat-controlled heater 42 which is different from the body temperature of the body treating living being does not deviate significantly.
  • Shock waves are generated in a manner known per se by means of the shock wave generator according to the invention by applying a voltage pulse to the coil 5 by means of the pulse generator 17.
  • the coil 5 then builds up a magnetic field extremely rapidly, which induces a current in the membrane 19 which is opposite to the current flowing through the coil 5.
  • This current is accompanied by a magnetic field which is opposite to the magnetic field belonging to the current flowing through the coil 5.
  • the membrane 19 is suddenly moved away from the coil 5, whereby an initially flat shock wave is introduced into the acoustic propagation medium adjacent to the membrane 19, in the case of the shock wave generator according to the invention the liquid nitrogen.
  • the liquid nitrogen located between the membrane 19 and the solid plate 22, which brings the membrane 19 into the superconducting state, advantageously also serves as an acoustic propagation medium for the shock waves emanating from the membrane 19.
  • These pass through the solid plate 22 and between the solid plate 22 and the flat side of the converging lens 30 liquid.
  • the essentially flat shock wave entering the converging lens 30 is focused as a result of the lens effect of the converging lens 30 in the manner indicated by dash-dotted lines on a focus zone F which lies on the central axis M of the shock wave source.
  • shock wave generator is pressed by means of the sack 3 with the aid of a known, suitable locating device in such a position on the body 44 of the living being to be treated that the concretion K to be broken, for example the stone of a kidney N, is in the focus zone F.
  • the concrement K can be broken up into fragments by a series of shock waves that are so small that they can be excreted naturally.
  • the solid plate 22 which, as already mentioned, consists of a material with low thermal conductivity, serves the purpose of keeping the amount of heat supplied to the liquid nitrogen between the solid plate 22 and the membrane 19 per unit time as low as possible.
  • a roughly schematically indicated heat protection 43 is provided, which surrounds the entire housing 1 with the exception of the end closed by means of the bag 3.
  • the heat protection can be a body made of a suitable insulating material, e.g. Styrofoam (registered trademark), or an evacuated double-walled body, or both.
  • the heat protection 43 also prevents the liquid nitrogen located in the region of the coil 5 in the channel formed by the groove 9 and the disk 10 from being supplied with ambient heat.
  • the liquid located between the solid plate 22 and the converging lens 30 also serves the purpose of keeping the extreme temperatures of the liquid nitrogen away from the object to be sonicated, ie the body 44 of the living being to be treated, and in the region of the end engaging with the body 44 of the shock wave generator to ensure physiologically pleasant temperatures.
  • a further temperature adjustment takes place by means of the liquid enclosed between the collecting lens 30 and the bag 3, which also serves for the acoustic impedance adjustment to the conditions of the body 44 of the living being to be treated.
  • the liquid enclosed between the collecting lens 30 and the bag 3 which also serves for the acoustic impedance adjustment to the conditions of the body 44 of the living being to be treated.
  • the solid plate 22 and the collecting lens 30 and the liquids located between the membrane 19 and the solid plate 22 or the solid plate 22 and the collecting lens 30 are advisable for the solid plate 22 and the collecting lens 30 and the liquids located between the membrane 19 and the solid plate 22 or the solid plate 22 and the collecting lens 30 to choose substances which have material properties such that the acoustic losses in the direction of propagation of the shock waves limit through reflections and attenuation.
  • the acoustic impedances of the different materials should not differ significantly from one another in order to keep the reflection losses low.
  • oils, glycerols, alcohols, etc. may be used as liquids between the membrane 19 and the solid plate 22 in the future. Under certain circumstances, this would enable a further improvement of the acoustic adjustments and thus further reduced acoustic losses.
  • FIG. 2 A further variant of a shock wave generator according to the invention is shown in FIG. 2, with only the total here Shown with 45 designated shock wave source area of the shock wave generator is shown, which otherwise corresponds to that described above, which is why the same parts have the same reference numerals.
  • the membrane 46 is composed of a carrier 48, which can be made of titanium, for example, and one on the carrier 48 attached layer 47 of a material which can be brought into the superconducting state, for example barium-lanthanum-copper oxide.
  • the carrier 48 serves as mechanical fixation and stiffening for the layer 47 made of barium-lanthanum copper oxide, into which high currents can be induced, since it is adjacent to the coil 49.
  • the coil 49 is again arranged on the flat contact surface of a coil carrier 50 and wound spirally.
  • the coil 49 is made of a tube of material that can be put into the superconducting state, for example barium-lanthanum copper oxide, whereby liquid nitrogen, which puts this material in the superconducting state, through which the coil 49 forming tube flows. It is therefore unnecessary to provide a channel system in the coil carrier 50, which allows the liquid nitrogen to be brought into the area of the coil 49.
  • This has two connections 51 and 52, via which it is connected to the electrical pulse generator 17.
  • the connections 51 and 52 also serve as inlet and outlet for the liquid nitrogen and are accordingly connected to a pump 53 and a cooling unit 54.
  • the pump 53 and the cooling unit 54 are also responsible for the liquid nitrogen located between the membrane 46 and the solid plate 22, which is why the inlet line 25 and the outlet line 26 are connected in a corresponding manner to the pump 53 and the cooling unit 54.
  • shock wave generators which are used to crush concretions.
  • the invention can also be used in shock wave generators which serve any other purposes.
  • both the membrane and the coil are flat.
  • shock wave generators according to the invention can also be constructed in which the membrane and the coil do not have a flat shape, but are, for example, spherically curved around a common center.
  • high-temperature superconductors namely yttrium-barium-copper oxide and barium-lanthanum-copper oxide
  • yttrium-barium-copper oxide and barium-lanthanum-copper oxide have been described in connection with the exemplary embodiments as an example of the material which can be brought into the superconducting state and are contained in the coil and the membrane.
  • other (high-temperature) superconductors are also possible, in which case substances other than liquid nitrogen must or may be present in order to bring these materials into the superconducting state.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
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Description

Die Erfindung betrifft einen elektrisch antreibbaren akustischen Stoßwellengenerator, welcher als elektrisch leitende Elemente eine Spulenanordnung und eine mittels der Spulenanordnung elektrisch stoßartig antreibbare Membran aufweist, mittels derer Stoßwellen in ein an die Membran angrenzendes akustisches Ausbreitungsmedium einleitbar sind.The invention relates to an electrically drivable acoustic shock wave generator which has, as electrically conductive elements, a coil arrangement and a membrane which can be driven in an electric shock-like manner by means of the coil arrangement, by means of which shock waves can be introduced into an acoustic propagation medium adjacent to the membrane.

Derartige Stoßwellengeneratoren können für die unterschiedlichsten Zwecke verwendet werden, z.B. in der Medizin, um im Körper eines Patienten befindliche Konkremente nichtinvasiv zu zertrümmern oder pathologische Gewebeveränderungen ebenfalls nichtinvasiv zu behandeln. Außerdem können derartige Stoßwellengeneratoren in der Werkstoffprüfung eingesetzt werden, um Materialproben mit Stoßwellen zu beaufschlagen. Der Stoßwellengenerator wird stets in geeigneter Weise mit mit jeweils zu beschallenden Objekt akustisch gekoppelt, so daß die in dem akustischen Ausbreitungsmedium erzeugten Stoßwellen in das Objekt eingeleitet werden können. Der Stoßwellengenerator und das zu beschallende Objekt müssen dabei so ausgerichtet sein, daß der zu beschallende Bereich des Objektes sich im Ausbreitungsweg der Stoßwellen befindet. Falls der Stoßwellengenerator fokussierte Stoßwellen abgibt, muß außerdem sichergestellt sein, daß sich der zu beschallende Bereich des Objektes in dem Fokusbereich der Stoßwellen befindet.Such shock wave generators can be used for a wide variety of purposes, e.g. in medicine to non-invasively break up the stones in a patient's body or to treat non-invasive pathological tissue changes. In addition, such shock wave generators can be used in material testing to apply shock waves to material samples. The shock wave generator is always acoustically coupled in a suitable manner to the object to be irradiated, so that the shock waves generated in the acoustic propagation medium can be introduced into the object. The shock wave generator and the object to be sonicated must be aligned so that the area of the object to be sonicated is in the path of propagation of the shock waves. If the shock wave generator emits focused shock waves, it must also be ensured that the area of the object to be irradiated is in the focus area of the shock waves.

Ein Stoßwellengenerator der eingangs genannten Art ist in der US-A-4 674 505 =EP-A-0 133 665 beschrieben. Es handelt sich hierbei um einen sogenannten elektromagnetischen Stoßwellengenerator, dessen Wirkung darauf beruht, daß die Spulenanordnung bei Beaufschlagung mit einem Hochspannungsimpuls äußerst rasch ein Magnetfeld aufbaut, welches in die Membran einen Strom induziert, der dem durch die Spulenanordnung fließenden Strom entgegengesetzt ist und von einem dem zur Spulenanordnung gehörigen Magnetfeld entgegensetzten Magnetfeld bekleidet ist. Infolge der hierbei auftretenden Abstoßungskräfte wird die Membran schlagartig von der Spulenanordnung wegbewegt. Dabei wird ein Druckimpuls in das akustische Ausbreitungsmedium eingeleitet, der sich auf seinem Ausbreitungsweg allmählich zur Stoßwelle aufsteilt. Der Einfachheit halber soll im folgenden daher unabhängig davon, ob sich der Druckimpuls bereits zur Stoßwelle aufgesteilt hat oder noch nicht, stets von Stoßwellen die Rede sein.A shock wave generator of the type mentioned at the outset is described in US Pat. No. 4,674,505 = EP-A-0 133 665. It is a so-called electromagnetic shock wave generator, the effect of which is based on the fact that the coil arrangement, when subjected to a high-voltage pulse, builds up a magnetic field extremely quickly, which induces a current in the membrane which is opposite to the current flowing through the coil arrangement and is clad by a magnetic field opposite the magnetic field belonging to the coil arrangement. As a result of the repulsive forces that occur here, the membrane is suddenly moved away from the coil arrangement. A pressure pulse is introduced into the acoustic propagation medium, which gradually divides into a shock wave as it travels. For the sake of simplicity, we shall therefore always speak of shock waves below, regardless of whether the pressure pulse has already split up into the shock wave or not yet.

Für derartige Stoßwellengeneratoren gilt näherungsweise, daß der erzielbare Spitzendruck der Stoßwellen mit dem Quadrat des durch die Spulenanordnung fließenden Stromes steigt. In der Praxis hat sich gezeigt, daß bei den derzeit üblichen Stoßwellengeneratoren die Spulenanordnung mit Hochspannungsimpulsen in der Größenordnung von 10 bis 20 kV beaufschlagt werden muß, um Ströme in der Spulenanordnung hervorzurufen, deren Höhe zur Erzeugung von Stoßwellen ausreicht, die nach geeigneter Fokussierung den zur Zertrümmerung von Konkrementen im Körper von Lebewesen erforderlichen Spitzendruck aufweisen. Die Notwendigkeit, die Spulenanordnung mit Spannungen der genannten Höhe beaufschlagen zu müssen, wird in der Praxis als äußerst nachteilig angesehen, da die zur Erzielung einer ausreichenden elektrischen Spannungsfestigkeit des Stoßwellengenerators erforderlichen Isolationsmaßnahmen problematisch und sehr aufwendig sind. Außerdem wirken sich die genannten hohen Spannungen nachteilig auf die Lebensdauer nicht nur des Stoßwellengenerators sondern auch der elektrischen und elektromechanischen Bauteile der zum Antrieb des Stoßwellengenerators vorgesehenen Hochspannungs-Generatoreinrichtung aus.For such shock wave generators it is approximately the case that the peak pressure of the shock waves which can be achieved increases with the square of the current flowing through the coil arrangement. In practice, it has been shown that in the currently common shock wave generators, the coil arrangement with high-voltage pulses in the order of 10 to 20 kV must be applied in order to produce currents in the coil arrangement, the level of which is sufficient to generate shock waves which, after suitable focusing, can be used for Shattering of concrements in the body of living beings have the required peak pressure. The necessity of having to apply voltages of the stated height to the coil arrangement is considered to be extremely disadvantageous in practice, since the insulation measures required to achieve a sufficient electrical strength of the shock wave generator are problematic and very complex. In addition, the high voltages mentioned have a disadvantageous effect on the service life of not only the shock wave generator but also the electrical and electromechanical components of the high-voltage generator device provided for driving the shock wave generator.

Der Erfindung liegt daher die Aufgabe zugrunde, einen Stoßwellengenerator der eingangs genannten Art so auszubilden, daß bereits bei Beaufschlagung der Spulenanordnung mit elektrischen Impulsen vergleichsweise geringer Spannung ein hoher Spitzendruck der Stoßwellen erzielbar ist.The invention is therefore based on the object of designing a shock wave generator of the type mentioned in such a way that a relatively high peak pressure of the shock waves can be achieved even when the coil arrangement is subjected to comparatively low voltage.

Nach der Erfindung wird diese Aufgabe dadurch gelöst, daß wenigstens eines der elektrisch leitenden Elemente, also Spulenanordnung und/oder Membran, in den supraleitenden Zustand versetzbares Material enthält und daß Mittel zum Versetzen des in den wenigstens einen elektrisch leitenden Element enthaltenden Materials in den supraleitenden Zustand vorgesehen sind. Da in diesem Falle die ohm'sche Widerstandskomponente der Spulenanordnung praktisch vollständig verschwindet und/oder in die Membran infolge der Supraleitung höhere Ströme induziert werden, reichen im Vergleich zum Stand der Technik bei dem erfindungsgemäßen Stoßwellengenerator elektrische Impulse geringerer Spannung aus, um einen bestimmten Strom in der Spulenanordnung fließen zu lassen. Alternativ oder zusätzlich ist eine (weitere) Verringerung der Spannung der elektrischen Impulse möglich, da infolge der höheren in der Membran fließenden Ströme größere Abstoßungskräfte auftreten. Es wird also deutlich, daß im Falle des erfindungsgemäßen Stoßwellengenerators im Vergleich zum Stand der Technik geringere Spannungen ausreichen, um Stoßwellen eines bestimmten Spitzendruckes zu erzeugen. Es versteht sich, daß die Spulenanordnung und die zu dieser führenden elektrischen Leitungen möglichst induktivitätsarm ausgeführt sein sollten, da andernfalls die ohm'sche Widerstandskomponente nur einen geringen Teil des Gesamtwiderstandes darstellen würde, deren Elimination durch Supraleitung keine wesentliche Verbesserung bringen könnte.According to the invention, this object is achieved in that at least one of the electrically conductive elements, that is to say the coil arrangement and / or membrane, contains material which can be set into the superconducting state and that means for setting the material containing the at least one electrically conductive element into the superconducting state are provided. In this case, since the ohmic resistance component of the coil arrangement practically completely disappears and / or higher currents are induced in the membrane as a result of superconductivity, in comparison with the prior art, electrical impulses of a lower voltage are sufficient in the shock wave generator according to the invention to reduce a specific current to let the coil assembly flow. As an alternative or in addition, a (further) reduction in the voltage of the electrical pulses is possible, since larger repulsive forces occur as a result of the higher currents flowing in the membrane. It is therefore clear that in the case of the shock wave generator according to the invention, lower voltages are sufficient in comparison to the prior art to generate shock waves of a certain peak pressure. It goes without saying that the coil arrangement and the electrical lines leading to it should be designed with as little inductance as possible, since otherwise the ohmic resistance component would represent only a small part of the total resistance, the elimination of which by superconductivity could not bring about any significant improvement.

Eine Variante der Erfindung sieht vor, daß die Spulenanordnung mittels eines Kühlmediums in den supraleitenden Zustand versetzbar ist, welches sich im Bereich der Spulenanordnung befindet. Da die Spulenanordnung in der Regel an einem Spulenträger fixiert sein muß, besteht die vorteilhafte Möglichkeit, den Spulenträger mit einem Kanal zu versehen, durch den das Kühlmedium möglichst dicht an der Spulenanordnung vorbeiströmt. Gemäß einer bevorzugten Variante der Erfindung ist jedoch vorgesehen, daß die Spulenanordnung aus einem Rohr in den supraleitenden Zustand versetzbaren Materials gewickelt ist und daß das Kühlmedium das Rohr durchströmt. Auf diese Weise ist es mit besonders geringem konstruktivem Aufwand möglich, die Spulenanordnung in den supraleitenden Zustand zu versetzen, da ein besonderes Kanalsystem oder dergleichen nicht erforderlich ist, um das Kühlmedium an die Spulenanordnung heranzuführen.A variant of the invention provides that the coil arrangement can be brought into the superconducting state by means of a cooling medium, which is located in the region of the coil arrangement. Since the coil arrangement generally has to be fixed to a coil carrier, there is the advantageous possibility of providing the coil carrier with a channel through which the cooling medium flows past the coil arrangement as closely as possible. According to a preferred variant of the invention, however, it is provided that the coil arrangement is wound from a tube into material that can be brought into the superconducting state and that the cooling medium flows through the tube. That way it is special with low design effort possible to put the coil arrangement in the superconducting state, since a special channel system or the like is not required to bring the cooling medium to the coil arrangement.

Eine weitere besonders bevorzugte Ausführungsform der Erfindung sieht vor, daß als akustisches Ausbreitungsmedium ein die Membran in den supraleitenden Zustand versetzendes Kühlmittel vorgesehen ist, welches in einem der Membran vorgelagerten Raum aufgenommen ist. Im Falle dieser Ausführungsform wird also das Kühlmittel, das dazu dient, die Membran in den supraleitenden Zustand zu versetzen, zugleich als akustisches Ausbreitungsmedium für die Stoßwellen verwendet, so daß kein zusätzlicher konstruktiver Aufwand erforderlich ist, um die Membran in den supraleitenden Zustand versetzen zu können. Gemäß einer weiteren Variante der Erfindung ist vorgesehen, daß der das Kühlmittel aufnehmende Raum an seinem von der Membran entfernten Ende mit einer Feststoffplatte abgeschlossen ist, welche aus Stoßwellen leitendem Material, d.h. einem Material mit geringer akustischer Dämpfung für Stoßwellen, gebildet ist, und daß die von der Membran abgewandte Seite der Feststoffplatte an einen zweiten Raum angrenzt, in welchem sich ein Stoßwellen leitendes Medium befindet, dessen Temperatur höher als die des Kühlmittels ist. Diese Maßnahme ist insbesondere dann von Bedeutung, wenn die Membran aus einem solchen Material gebildet ist, daß sehr niedrige, d.h. deutlich unterhalb von 170 Kelvin liegende Temperaturen zum Erreichen des supraleitenden Zustandes erforderlich sind, da dann von der Membran aus gesehen jenseits der Feststoffplatte "erträgliche Temperaturen", beispielsweise in der Größenordnung der gewöhnlichen Raumtemperatur, erzielbar sind. In Abhängigkeit von der Dicke der Feststoffplatte läßt sich der Wärmestrom von dem die Stoßwellen leitenden Medium durch die Feststoffplatte in das Kühlmittel beeinflussen, da der Wärmestrom um so geringer ist, je größer die Dicke der Feststoffplatte ist. Zweckmäßigerweise ist vorgesehen, daß das Kühlmedium den Kanal bzw. das die Spulenanordnung bildende Rohr und/oder das Kühlmittel den der Membran vorgelagerten Raum und/oder das Stoßwellen leitende Medium den zweiten Raum durch-strömt.A further particularly preferred embodiment of the invention provides that a coolant which brings the membrane into the superconducting state and is accommodated in a space upstream of the membrane is provided as the acoustic propagation medium. In the case of this embodiment, the coolant that serves to put the membrane in the superconducting state is also used as an acoustic propagation medium for the shock waves, so that no additional design effort is required to be able to put the membrane in the superconducting state . According to a further variant of the invention it is provided that the coolant-receiving space is closed at its end remote from the membrane with a solid plate, which is formed from shock wave conductive material, ie a material with low acoustic damping for shock waves, and that side of the solid plate facing away from the membrane adjoins a second space in which there is a medium which conducts shock waves and whose temperature is higher than that of the coolant. This measure is particularly important if the membrane is formed from such a material that very low temperatures, ie temperatures well below 170 Kelvin, are required to achieve the superconducting state, since then, when viewed from the membrane, it is "tolerable" beyond the solid plate Temperatures ", for example in the order of the usual room temperature, can be achieved. Depending on the thickness of the solid plate, the heat flow from the medium conducting the shock waves through the solid plate into the coolant can be influenced, since the greater the thickness of the solid plate, the smaller the heat flow. It is expediently provided that the cooling medium the channel or the tube forming the coil arrangement and / or the coolant the space upstream of the membrane and / or the shock wave conducting medium flows through the second space.

Um eine verlustarme Einleitung der Stoßwellen in ein zu beschallendes Objekt zu ermöglichen, ist erforderlichenfalls, d.h. dann, wenn die akustische Impedanz des in dem zweiten Raum befindlichen Mediums wesentlich von der des zu beschallenden Objektes abweicht, eine Trennwand aus Stoßwellen leitendem Material vorgesehen, welche den zweiten Raum an seinem von der Feststoffplatte entfernten Ende abschließt, wobei an die dem zweiten Raum abgewandte Seite der Trennwand ein Stoff angrenzt, dessen akustische Impedanz der eines zu beschallenden Objektes im wesentlichen entspricht.In order to enable a low-loss introduction of the shock waves into an object to be irradiated, if necessary, i. if the acoustic impedance of the medium located in the second room differs substantially from that of the object to be sonicated, a partition wall made of shock wave-conducting material is provided, which closes the second room at its end remote from the solid plate, the one facing away from the second room Side of the partition is bordered by a material whose acoustic impedance corresponds essentially to that of an object to be irradiated.

Falls die von der Membran ausgehenden Stoßwellen der Fokussierung bedürfen, ist gemäß einer besonders bevorzugten Ausführungsform der Erfindung vorgesehen, daß die Trennwand als akustische Linse ausgebildet ist. Falls also sowohl eine Trennwand als auch eine akustische Linse erforderlich sind, kann auf diese Weise der erforderliche konstruktive Aufwand ganz erheblich gesenkt werden. Bei der Berechnung der Krümmung der Linse können übrigens die durch einen eventuell vorhandenen Temperaturgradienten des Linsenmaterials quer zur Ausbreitungsrichtung der Stoßwellen bedingten Änderungen des Brechungsindex des Linsenmaterials berücksichtigt werden.If the shock waves emanating from the membrane require focusing, it is provided according to a particularly preferred embodiment of the invention that the partition is designed as an acoustic lens. In this way, if both a partition and an acoustic lens are required, the required design effort can be reduced considerably. Incidentally, when calculating the curvature of the lens, the changes in the refractive index of the lens material caused by a possibly existing temperature gradient of the lens material transverse to the direction of propagation of the shock waves can be taken into account.

Eine Ausführungsform der Erfindung sieht vor, daß ein flexibler Sack zur akustischen Ankopplung des Stoßwellengenerators an ein zu beschallendes Lebewesen vorgesehen ist, und daß an die Innenseite des Balges ein Stoßwellen leitendes Material angrenzt, dessen Temperatur von der Körpertemperatur des Lebewesens nicht wesentlich abweicht. In Abhängigkeit von derjenigen Temperatur, bei deren Erreichen das Material der Membran in den supraleitenden Zustand übergeht, kann es sich bei dem an den Balg angrenzenden Material um das in dem der Membran vorgelagerten Raum befindlichen Kühlmittel, um das in dem zweiten Raum befindliche Medium, um den an die dem zweiten Raum abgewandte Seite der Trennwand angrenzenden Stoff oder ein besonderes Material handeln.One embodiment of the invention provides that a flexible sack is provided for acoustically coupling the shock wave generator to a living being to be sonicated, and that a shock wave conducting material adjoins the inside of the bellows, the temperature of which does not differ significantly from the body temperature of the living being. Depending on the temperature at which the material of the membrane changes into the superconducting state, the material adjacent to the bellows may be the coolant in the space upstream of the membrane, or the medium in the second space the one facing away from the second room Act on the side of the partition adjacent fabric or a special material.

Es versteht sich, daß sich die akustischen Impedanzen der im Ausbreitungsweg der Stoßwellen befindlichen Substanzen möglichst wenig von der akustischen Impedanz des zu beschallenden Objektes unterscheiden sollten, um Verluste durch Reflexionen nach Möglichkeit zu vermeiden.It goes without saying that the acoustic impedances of the substances in the propagation path of the shock waves should differ as little as possible from the acoustic impedance of the object to be irradiated in order to avoid losses due to reflections as far as possible.

Ausführungsbeispiele der Erfindung sind in den beigefügten Zeichnungen dargestellt. Es zeigen:

Fig. 1
einen Längsschnitt durch einen erfindungsgemäßen Stoßwellengenerator in schematischer Darstellung, und
Fig. 2
ein Detail einer Variante eines weiteren erfindungsgemäßen Stoßwellengenerators im Längsschnitt in schematischer Darstellung.
Embodiments of the invention are shown in the accompanying drawings. Show it:
Fig. 1
a longitudinal section through a shock wave generator according to the invention in a schematic representation, and
Fig. 2
a detail of a variant of a further shock wave generator according to the invention in longitudinal section in a schematic representation.

Die Fig. 1 zeigt einen zur Zertrümmerung von Konkrementen dienenden Stoßwellengenerator, der ein rohrförmiges Gehäuse 1 aufweist, das an seinem einen Ende durch eine insgesamt mit 2 bezeichnete Stoßwellenquelle und an seinem anderen Ende durch einen flexiblen Sack 3 verschlossen ist.1 shows a shock wave generator which serves to break up concrements and has a tubular housing 1 which is closed at one end by a shock wave source, generally designated 2, and at the other end by a flexible bag 3.

Die Stoßwellenquelle 2 weist eine auf einer ebenen Auflagefläche eines Spulenträgers 4 angeordnete Spule 5 auf. Diese besitzt die Anschlüsse 6 und 7, wobei die die Anschlüsse 6 und 7 verbindenden Windungen der Spule 5, eine der Windungen ist mit dem Bezugszeichen 8 versehen, spiralförmig verlaufen. Der Spulenträger 4 ist aus einem elektrisch isolierenden Werkstoff, z.B. Aluminiumoxidkeramik, gebildet. Der Raum zwischen den Windungen 8 der Spule 5 ist mit einem elektrisch isolierenden Gießharz, z.B. Araldit (eingetragenes Warenzeichen), ausgefüllt. Die Spule 5 besteht aus einem in den supraleitenden Zustand versetzbaren Werkstoff, z.B. Yttrium-Barium-Kupfer-Oxid, das bis zu Temperaturen von etwa 90 Kelvin supraleitend bleibt.The shock wave source 2 has a coil 5 arranged on a flat contact surface of a coil carrier 4. This has the connections 6 and 7, the turns of the coil 5 connecting the connections 6 and 7, one of the turns being provided with the reference symbol 8, running in a spiral. The coil carrier 4 is formed from an electrically insulating material, for example aluminum oxide ceramic. The space between the turns 8 of the coil 5 is filled with an electrically insulating casting resin, for example araldite (registered trademark). The coil 5 consists of a material which can be put into the superconducting state, for example yttrium-barium-copper oxide, which remains superconducting up to temperatures of approximately 90 Kelvin.

Um die Spule 5 in den supraleitenden Zustand versetzen zu können, ist in den Spulenträger 4 eine spiralförmige Nut 9 eingelassen, die mit einer Scheibe 10, die aus dem gleichen Material wie der Spulenträger 4 besteht, flüssigkeitsdicht verschlossen ist, so daß ein den Zulauf 11 mit dem Ablauf 12 verbindender Kanal vorliegt. An diese sind die Zulaufleitung 13 und die Ablaufleitung 14 angeschlossen. Mit Hilfe einer Pumpe 15 wird flüssiger Stickstoff, dessen Temperatur von 77 Kelvin ohne weiteres ausreicht, um das Material der Spule 5 in den supraleitenden Zustand zu versetzen, als Kühlmedium durch den Kanal gepumpt. Um sicherstellen zu können, daß der Stickstoff in seinem flüssigen Zustand bleibt, ist ein Kühlaggregat 16 vorhanden. Die Anschlüsse 6 und 7 der Spule 5 sind mit einem elektrischen Impulsgenerator 17 verbunden.In order to be able to put the coil 5 in the superconducting state, a spiral groove 9 is embedded in the coil carrier 4, which is sealed liquid-tight with a disk 10, which is made of the same material as the coil carrier 4, so that an inlet 11 with the outlet 12 connecting channel is present. The inlet line 13 and the outlet line 14 are connected to this. With the help of a pump 15, liquid nitrogen, the temperature of 77 Kelvin is easily sufficient to bring the material of the coil 5 into the superconducting state, is pumped through the channel as a cooling medium. In order to be able to ensure that the nitrogen remains in its liquid state, a cooling unit 16 is provided. The connections 6 and 7 of the coil 5 are connected to an electrical pulse generator 17.

Unter Zwischenfügung einer Isolierfolie 18 ist der von dem Spulenträger 4 abgewandten Seite der Spule 5 gegenüberliegend eine kreisscheibenförmige, ebene Membran 19 angeordnet, die ebenfalls aus einem in den supraleitenden Zustand versetzbaren Material, beispielsweise Barium-Lanthan-Kupfer-Oxid, besteht. Die Membran 19, die Isolierfolie 18 und die Spule 5 sind mit dem Spulenträger 4 und der Scheibe 10 mittels eines an dem Spulenträger 4 angebrachten Zentrierrandes zu einer Einheit zusammengefaßt. Diese Einheit ist mittels eines an dem Spulenträger 4 anliegenden Ringes 20 und mehrerer Schrauben, es sind lediglich die Mittellinien zweier Schrauben strichpunktiert angedeutet, gegen einen in der Bohrung des Gehäuses 1 vorgesehenen Absatz 21 gepreßt. Dabei liegt die Membran 19, eventuell unter Zwischenfügung geeigneter nicht dargestellter Dichtmittel, flüssigkeitsdicht an dem Absatz 21 an. An der von der Membran 19 abgewandten Seite des Absatzes 21 liegt eine Feststoffplatte 22, die aus einem Material geringer Wärmeleitfähigkeit, beispielsweise aus Polystyrol besteht, flüssigkeitsdicht an. In dem zwischen der Feststoffplatte 22 und der Membran 19 begrenzten Raum befindet sich flüssiger Stickstoff, durch dessen Anwesenheit die Membran 19 in den supraleitenden Zustand versetzt wird. Der von der Membran 19 und der Feststoffplatte 22 begrenzte Raum weist einen Zulauf 23 und einen Ablauf 24 auf, an die eine Zulaufleitung 25 und eine Ablaufleitung 26 angeschlossen sind, so daß mittels einer Pumpe 27 der flüssige Stickstoff als Kühlmittel umgewälzt werden kann, wobei wieder ein Kühlaggregat 28 vorhanden ist, so daß gewährleistet ist, daß der Stickstoff seinen flüssigen Zustand beibehält.With the interposition of an insulating film 18, a disc-shaped, flat membrane 19 is arranged opposite the side of the coil 5 facing away from the coil carrier 4, which also consists of a material that can be put into the superconducting state, for example barium-lanthanum-copper oxide. The membrane 19, the insulating film 18 and the coil 5 are combined with the coil carrier 4 and the disk 10 by means of a centering edge attached to the coil carrier 4 to form a unit. This unit is pressed against a shoulder 21 provided in the bore of the housing 1 by means of a ring 20 and a plurality of screws resting on the coil carrier 4 and several screws; only the center lines of two screws are indicated by dash-dotted lines. Here, the membrane 19, possibly with the interposition of suitable sealants, not shown, bears against the shoulder 21 in a liquid-tight manner. On the side of the shoulder 21 facing away from the membrane 19 there is a solid plate 22 which is made of a material with low thermal conductivity, for example polystyrene, in a liquid-tight manner. In the space between the solid plate 22 and the membrane 19 there is liquid nitrogen, the presence of which causes the membrane 19 to be brought into the superconducting state. The limited by the membrane 19 and the solid plate 22 Room has an inlet 23 and an outlet 24, to which an inlet line 25 and an outlet line 26 are connected, so that the liquid nitrogen can be circulated as a coolant by means of a pump 27, again with a cooling unit 28, so that it is ensured that the nitrogen maintains its liquid state.

Auf einem weiteren Absatz 29 der Bohrung des Gehäuses 1 ist eine plan-konkave akustische Sammellinse 30 fixiert, welche beispielsweise aus Polystyrol besteht. Die der Feststoffplatte 22 zugewandte plane Seite der Sammellinse 30 und die dieser zugewandte Seite der Feststoffplatte 22 begrenzen einen weiteren Raum, in dem sich eine Flüssigkeit als Stoßwellen leitendes Medium befindet, deren Temperatur von der normalen Umgebungstemperatur, also etwa 20 bis 30° C, nicht wesentlich abweicht. Als Flüssigkeit kommt beispielsweise Glyzerin in Frage, dessen akustische Impedanz ähnlich der von Polystyrol ist. Da eine bestimmte Wärmenmenge aus der Flüssigkeit durch die Feststoffplatte 22 hindurch in den an die Membran 19 angrenzenden flüssigen Stickstoff abfließt, wird die zwischen Sammellinse 30 und Feststoffplatte 22 befindliche Flüssigkeit über an einen Zulauf 31 und einen Ablauf 32 angeschlossene Zulauf- und Ablaufleitungen 33 bzw. 34 mit Hilfe einer Pumpe 35 durch eine Heizung 36 geführt, die den Wärmeverlust ausgleicht und in an sich bekannter Weise mittels einer thermostatischen Regelung eine konstante Temperatur der Flüssigkeit gewährleistet.On a further shoulder 29 of the bore of the housing 1, a plane-concave acoustic converging lens 30 is fixed, which consists, for example, of polystyrene. The flat side of the converging lens 30 facing the solid plate 22 and the side of the solid plate 22 facing this delimit a further space in which a liquid as a shock wave-conducting medium is located, the temperature of which does not deviate from the normal ambient temperature, that is to say about 20 to 30 ° C. deviates significantly. Glycerin, for example, is possible as a liquid, whose acoustic impedance is similar to that of polystyrene. Since a certain quantity of heat flows out of the liquid through the solid plate 22 into the liquid nitrogen adjacent to the membrane 19, the liquid located between the collecting lens 30 and the solid plate 22 is fed via inlet and outlet lines 33 and / or outlet lines 33 connected to an inlet 31 and an outlet 32. 34 with the help of a pump 35 through a heater 36, which compensates for the heat loss and ensures a constant temperature of the liquid in a manner known per se by means of thermostatic control.

Der zwischen der Sammellinse 30 und dem Sack 3 befindliche Raum ist mit einem weiteren flüssigen Stoff, beispielsweise Wasser, gefüllt, dessen akustische Impedanz der des Gewebes des zu behandelnden Lebewesens möglichst exakt angepaßt ist. Der weitere flüssige Stoff, der über einen Zulauf 37 sowie einen Ablauf 38 und an diese angeschlossene Zulauf- und Ablaufleitungen 39 bzw. 40 mittels einer Pumpe 41 umgewälzt wird, wird mittels einer thermostatgesteuerten Heizung 42 auf einer Temperatur gehalten, die von der Körpertemperatur des zu behandelnden Lebewesens nicht wesentlich abweicht.The space between the collecting lens 30 and the sack 3 is filled with another liquid substance, for example water, the acoustic impedance of which is matched as precisely as possible to that of the tissue of the living being to be treated. The further liquid substance, which is circulated by means of a pump 41 via an inlet 37 and an outlet 38 and the inlet and outlet lines 39 and 40 connected to them, is kept at a temperature by means of a thermostat-controlled heater 42 which is different from the body temperature of the body treating living being does not deviate significantly.

Mittels des erfindungsgemäßen Stoßwellengenerators werden Stoßwellen in an sich bekannter Weise erzeugt, indem die Spule 5 mittels des Impulsgenerators 17 mit einem Spannungsimpuls beaufschlagt wird. Die Spule 5 baut daraufhin äußerst rasch ein Magnetfeld auf, welches in die Membran 19 einen Strom induziert, der dem durch die Spule 5 fließenden Strom entgegengesetzt ist. Dieser Strom ist von einem Magnetfeld begleitet, das dem zu dem durch die Spule 5 fließenden Strom gehörigen Magnetfeld entgegengesetzt ist. Infolge der hierbei auftretenden Abstoßungskräfte wird die Membran 19 schlagartig von der Spule 5 wegbewegt, wodurch in das an die Membran 19 angrenzende akustische Ausbreitungsmedium, im Falle des erfindungsgemäßen Stoßwellengenerators den flüssigen Stickstoff, eine zunächst ebene Stoßwelle eingeleitet wird. Im Gegensatz zum Stand der Technik sind im Falle des erfindungsgemäßen Stoßwellengenerators infolge des Umstandes, daß sich sowohl die Spule 5 als auch die Membran 19 im supraleitenden Zustand befinden, wesentlich geringere Spannungen zur Erzeugung einer Stoßwelle eines bestimmten Energiegehaltes und eines bestimmten Spitzendruckes erforderlich. Dies hat zum einen seinen Grund darin, daß unter der Voraussetzung eines induktivitätsarmen Aufbaus des Stoßwellengenerators infolge des Wegfalls der ohm'schen Widerstandskomponente der Spule 5 bereits vergleichsweise geringe Spannungen ausreichen, um die jeweils erforderlichen Ströme fließen zu lassen. Zum anderen können infolge des Wegfalls der ohm'schen Widerstandskomponente der Membran in diese höhere Ströme induziert werden, die wiederum zu höheren Abstoßungskräften führen, so daß eine weitere Verminderung der Spannung, mit der die Spule 5 zu beaufschlagen ist, möglich wird.Shock waves are generated in a manner known per se by means of the shock wave generator according to the invention by applying a voltage pulse to the coil 5 by means of the pulse generator 17. The coil 5 then builds up a magnetic field extremely rapidly, which induces a current in the membrane 19 which is opposite to the current flowing through the coil 5. This current is accompanied by a magnetic field which is opposite to the magnetic field belonging to the current flowing through the coil 5. As a result of the repulsive forces occurring here, the membrane 19 is suddenly moved away from the coil 5, whereby an initially flat shock wave is introduced into the acoustic propagation medium adjacent to the membrane 19, in the case of the shock wave generator according to the invention the liquid nitrogen. In contrast to the prior art, in the case of the shock wave generator according to the invention, due to the fact that both the coil 5 and the membrane 19 are in the superconducting state, much lower voltages are required to generate a shock wave of a certain energy content and a certain peak pressure. One reason for this is that under the condition of a low-inductance construction of the shock wave generator due to the elimination of the ohmic resistance component of the coil 5, comparatively low voltages are already sufficient to allow the respectively required currents to flow. On the other hand, as a result of the omission of the ohmic resistance component of the membrane, higher currents can be induced therein, which in turn lead to higher repulsive forces, so that a further reduction in the voltage to be applied to the coil 5 becomes possible.

Im Falle des Stoßwellengenerators gemäß Fig. 1 dient der zwischen der Membran 19 und der Feststoffplatte 22 befindliche flüssige Stickstoff, der die Membran 19 in den supraleitenden Zustand versetzt, in vorteilhafter Weise zugleich als akustisches Ausbreitungsmedium für die von der Membran 19 ausgehenden Stoßwellen. Diese durchlaufen die Feststoffplatte 22 sowie die zwischen der Feststoffplatte 22 und der planen Seite der Sammellinse 30 befindliche Flüssigkeit. Die in die Sammellinse 30 eintretende im wesentlichen ebene Stoßwelle wird infolge der Linsenwirkung der Sammellinse 30 in der strichpunktiert angedeuteten Weise auf eine Fokuszone F fokussiert, die auf der Mittelachse M der Stoßwellenquelle liegt. Wird der Stoßwellengenerator mittels des Sackes 3 unter Zuhilfenahme einer an sich bekannten, geeigneten Ortungsvorrichtung in einer solchen Position an den Körper 44 des zu behandelnden Lebewesens angepreßt, daß sich das zu zertrümmernde Konkrement K, beispielsweise der Stein einer Niere N, in der Fokuszone F befindet, kann das Konkrement K durch eine Serie von Stoßwellen in Fragmente zertrümmert werden, die so klein sind, daß sie auf natürlichem Wege ausgeschieden werden können.In the case of the shock wave generator according to FIG. 1, the liquid nitrogen located between the membrane 19 and the solid plate 22, which brings the membrane 19 into the superconducting state, advantageously also serves as an acoustic propagation medium for the shock waves emanating from the membrane 19. These pass through the solid plate 22 and between the solid plate 22 and the flat side of the converging lens 30 liquid. The essentially flat shock wave entering the converging lens 30 is focused as a result of the lens effect of the converging lens 30 in the manner indicated by dash-dotted lines on a focus zone F which lies on the central axis M of the shock wave source. If the shock wave generator is pressed by means of the sack 3 with the aid of a known, suitable locating device in such a position on the body 44 of the living being to be treated that the concretion K to be broken, for example the stone of a kidney N, is in the focus zone F. , the concrement K can be broken up into fragments by a series of shock waves that are so small that they can be excreted naturally.

Die Feststoffplatte 22, die wie bereits erwähnt aus einem Material geringer Wärmeleitfähigkeit besteht, dient dem Zweck, die dem zwischen der Feststoffplatte 22 und der Membran 19 befindlichen flüssigen Stickstoff pro Zeiteinheit zugeführte Wärmemenge möglichst niedrig zu halten. Aus dem gleichen Grunde ist ein grob schematisch angedeuteter Wärmeschutz 43 vorgesehen, der das gesamte Gehäuse 1 mit Ausnahme des mittels des Sackes 3 verschlossenen Endes umgibt. Bei dem Wärmeschutz kann es sich um einen Körper aus einem geeigneten Dämmaterial, z.B. Styropor (eingetragenes Warenzeichen), oder einen evakuierten doppelwandigen Körper oder beides handeln. Der Wärmeschutz 43 verhindert außerdem, daß dem im Bereich der Spule 5 in dem durch die Nut 9 und die Scheibe 10 gebildeten Kanal befindlichen flüssigen Stickstoff Umgebungswärme zugeführt wird.The solid plate 22, which, as already mentioned, consists of a material with low thermal conductivity, serves the purpose of keeping the amount of heat supplied to the liquid nitrogen between the solid plate 22 and the membrane 19 per unit time as low as possible. For the same reason, a roughly schematically indicated heat protection 43 is provided, which surrounds the entire housing 1 with the exception of the end closed by means of the bag 3. The heat protection can be a body made of a suitable insulating material, e.g. Styrofoam (registered trademark), or an evacuated double-walled body, or both. The heat protection 43 also prevents the liquid nitrogen located in the region of the coil 5 in the channel formed by the groove 9 and the disk 10 from being supplied with ambient heat.

Die zwischen der Feststoffplatte 22 und der Sammellinse 30 befindliche Flüssigkeit dient übrigens dem Zweck, die extremen Temperaturen des flüssigen Stickstoffes von dem zu beschallenden Objekt, d.h. dem Körper 44 des zu behandelnden Lebewesens, fernzuhalten und im Bereich des mit dem Körper 44 in Eingriff stehenden Endes des Stoßwellengenerators für physiologisch angenehme Temperaturen zu sorgen.The liquid located between the solid plate 22 and the converging lens 30 also serves the purpose of keeping the extreme temperatures of the liquid nitrogen away from the object to be sonicated, ie the body 44 of the living being to be treated, and in the region of the end engaging with the body 44 of the shock wave generator to ensure physiologically pleasant temperatures.

Eine weitere Temperaturanpassung erfolgt mittels der zwischen der Sammellinse 30 und dem Sack 3 eingeschlossenen Flüssigkeit, die außerdem der akustischen Impedanzanpassung an die Verhältnisse des Körpers 44 des zu behandelnden Lebewesens dient. Insbesondere wenn menschliche Patienten behandelt werden sollen, empfiehlt es sich als Flüssigkeit zwischen Sack 3 und Sammellinse 30 Wasser vorzusehen, da dessen akustische Impedanz der von menschlichem Körpergewebe recht genau entspricht.A further temperature adjustment takes place by means of the liquid enclosed between the collecting lens 30 and the bag 3, which also serves for the acoustic impedance adjustment to the conditions of the body 44 of the living being to be treated. In particular, if human patients are to be treated, it is advisable to provide water as a liquid between sack 3 and collecting lens 30, since its acoustic impedance corresponds exactly to that of human body tissue.

Es empfiehlt sich für die Feststoffplatte 22 sowie die Sammellinse 30 und die zwischen der Membran 19 und der Feststoffplatte 22 bzw. der Feststoffplatte 22 und der Sammellinse 30 befindlichen Flüssigkeiten Stoffe zu wählen, die solche Materialeigenschaften aufweisen, daß sich die akustischen Verluste in Ausbreitungsrichtung der Stoßwellen durch Reflexionen und Dämpfung in Grenzen halten. So sollen sich beispielsweise die akustischen Impedanzen der verschiedenen Stoffe nicht stark voneinander unterscheiden, um die Reflexionsverluste klein zu halten. Bei Verwendung von flüssigem Argon mit einer akustischen Impedanz von 1.1075 x 10³ kg/M² s als Flüssigkeit zwischen Membran 19 und Feststoffplatte 22, Polystyrol mit einer akustischen Impedanz von 2.800 x 10³ kg/m² s als Material für die Feststoffplatte 22 und die Sammellinse 30 und Glyzerin mit einer akustischen Impedanz von 2.420 x 10³ kg/M² s als Flüssigkeit zwischen Feststoffplatte 22 und Linse 30 sind die Verluste mit denen von herkömmlich aufgebauten Stoßwellengeneratoren mit Wasser als akustischem Ausbreitungsmedium zwischen Membran und Sack durchaus vergleichbar. - Sollten auf dem Gebiet der (Hochtemperatur-) Supralleitung weitere Fortschritte erzielt werden, können als Flüssigkeiten zwischen der Membran 19 und der Feststoffplatte 22 künftig eventuell Öle, Glyzerine, Alkohole usw. eingesetzt werden. Dies würde unter Umständen eine weitere Verbesserung der akustischen Anpassungen und somit weiter verringerte akustische Verluste ermöglichen.It is advisable for the solid plate 22 and the collecting lens 30 and the liquids located between the membrane 19 and the solid plate 22 or the solid plate 22 and the collecting lens 30 to choose substances which have material properties such that the acoustic losses in the direction of propagation of the shock waves limit through reflections and attenuation. For example, the acoustic impedances of the different materials should not differ significantly from one another in order to keep the reflection losses low. When using liquid argon with an acoustic impedance of 1.1075 x 10³ kg / M² s as liquid between membrane 19 and solid plate 22, polystyrene with an acoustic impedance of 2.800 x 10³ kg / m² s as material for solid plate 22 and converging lens 30 and Glycerin with an acoustic impedance of 2,420 x 10³ kg / M² s as a liquid between the solid plate 22 and lens 30, the losses are quite comparable to those of conventionally constructed shock wave generators with water as the acoustic propagation medium between the membrane and the bag. - Should further progress be made in the field of (high-temperature) superconductivity, oils, glycerols, alcohols, etc. may be used as liquids between the membrane 19 and the solid plate 22 in the future. Under certain circumstances, this would enable a further improvement of the acoustic adjustments and thus further reduced acoustic losses.

Eine weitere Variante eines erfindungsgemäßen Stoßwellengenerators ist in Fig. 2 dargestellt, wobei hier nur der die insgesamt mit 45 bezeichnete Stoßwellenquelle enthaltende Bereich des Stoßwellengenerators dargestellt ist, der im übrigen mit dem zuvor beschriebenen übereinstimmt, weshalb jeweils gleiche Teile die gleichen Bezugszeichen tragen.A further variant of a shock wave generator according to the invention is shown in FIG. 2, with only the total here Shown with 45 designated shock wave source area of the shock wave generator is shown, which otherwise corresponds to that described above, which is why the same parts have the same reference numerals.

Im Gegensatz zu dem zuvor beschriebenen Ausführungsbeispiel, wo die Membran 19 insgesamt aus in den supraleitenden Zustand versetzbaren Material besteht, setzt sich im Falle der Stoßwellenquelle 45 die Membran 46 aus einem Träger 48, der beispielsweise aus Titan bestehen kann, und einer auf dem Träger 48 angebrachten Schicht 47 eines in den supraleitenden Zustand versetzbaren Materials, beispielsweise Barium-Lanthan-Kupfer-Oxid, zusammen. Der Träger 48 dient als mechanische Fixierung und Versteifung für die Schicht 47 aus Barium-Lanthan-Kupfer-Oxid, in die hohe Ströme induziert werden können, da sie der Spule 49 benachbart ist.In contrast to the exemplary embodiment described above, where the membrane 19 as a whole consists of material that can be put into the superconducting state, in the case of the shock wave source 45, the membrane 46 is composed of a carrier 48, which can be made of titanium, for example, and one on the carrier 48 attached layer 47 of a material which can be brought into the superconducting state, for example barium-lanthanum-copper oxide. The carrier 48 serves as mechanical fixation and stiffening for the layer 47 made of barium-lanthanum copper oxide, into which high currents can be induced, since it is adjacent to the coil 49.

Die Spule 49 ist wieder auf der ebenen Auflagefläche eines Spulenträgers 50 angeordnet und spiralförmig gewickelt. Im Gegensatz zu dem zuvor beschriebenen Ausführungsbeispiel ist die Spule 49 aus einem Rohr aus in den supraleitenden Zustand versetzbarem Material, beispielsweise Barium-Lanthan-Kupfer-Oxid, gefertigt, wobei flüssiger Stickstoff, der dieses Material in den supraleitenden Zustand versetzt, durch das die Spule 49 bildende Rohr strömt. Es erübrigt sich also, in dem Spulenträger 50 ein Kanalsystem vorzusehen, das es gestattet, den flüssigen Stickstoff in den Bereich der Spule 49 zu bringen. Diese verfügt über zwei Anschlüsse 51 und 52, über die sie mit dem elektrischen Impulsgenerator 17 verbunden ist. Die Anschlüsse 51 und 52 dienen zugleich als Zulauf und Ablauf für den flüssigen Stickstoff und sind dementsprechend mit einer Pumpe 53 und einen Kühlaggregat 54 verbunden. Die Pumpe 53 und das Kühlaggregat 54 sind zugleich für den zwischen der Membran 46 und der Feststoffplatte 22 befindlichen flüssigen Stickstoff zuständig, weshalb die Zulaufleitung 25 und die Ablaufleitung 26 in entsprechender Weise mit der Pumpe 53 und dem Kühlaggregat 54 verbunden sind.The coil 49 is again arranged on the flat contact surface of a coil carrier 50 and wound spirally. In contrast to the previously described embodiment, the coil 49 is made of a tube of material that can be put into the superconducting state, for example barium-lanthanum copper oxide, whereby liquid nitrogen, which puts this material in the superconducting state, through which the coil 49 forming tube flows. It is therefore unnecessary to provide a channel system in the coil carrier 50, which allows the liquid nitrogen to be brought into the area of the coil 49. This has two connections 51 and 52, via which it is connected to the electrical pulse generator 17. The connections 51 and 52 also serve as inlet and outlet for the liquid nitrogen and are accordingly connected to a pump 53 and a cooling unit 54. The pump 53 and the cooling unit 54 are also responsible for the liquid nitrogen located between the membrane 46 and the solid plate 22, which is why the inlet line 25 and the outlet line 26 are connected in a corresponding manner to the pump 53 and the cooling unit 54.

Die Ausführungsbeispiele betreffen ausschließlich Stoßwellengeneratoren, die zur Zertrümmerung von Konkrementen Verwendung finden. Die Erfindung kann jedoch auch bei Stoßwellengeneratoren eingesetzt werden, die beliebigen anderen Zwecken dienen. Im Falle der beschriebenen Ausführungsbeispiele sind sowohl die Membran als auch die Spule eben ausgebildet. Es können jedoch auch erfindungsgemäße Stoßwellengeneratoren aufgebaut werden, bei denen die Membran und die Spule keine ebene Gestalt aufweisen, sondern beispielsweise um einen gemeinsamen Mittelpunkt sphärisch gekrümmt sind.The exemplary embodiments relate exclusively to shock wave generators which are used to crush concretions. However, the invention can also be used in shock wave generators which serve any other purposes. In the case of the described exemplary embodiments, both the membrane and the coil are flat. However, shock wave generators according to the invention can also be constructed in which the membrane and the coil do not have a flat shape, but are, for example, spherically curved around a common center.

Als Beispiel für das in der Spule und der Membran enthaltene in den supraleitenden Zustand versetzbare Material wurden im Zusammenhang mit den Ausführungsbeispielen sogenannte Hochtemperatur-Supraleiter, nämlich Yttrium-Barium-Kupfer-Oxid und Barium-Lanthan-Kupfer-Oxid beschrieben. Selbstverständlich kommen auch andere (Hochtemperatur-) Supraleiter in Frage, wobei dann andere Substanzen als flüssiger Stickstoff vorhanden sein müssen bzw. sein können, um diese Materialien in den supraleitenden Zustand zu versetzen.So-called high-temperature superconductors, namely yttrium-barium-copper oxide and barium-lanthanum-copper oxide, have been described in connection with the exemplary embodiments as an example of the material which can be brought into the superconducting state and are contained in the coil and the membrane. Of course, other (high-temperature) superconductors are also possible, in which case substances other than liquid nitrogen must or may be present in order to bring these materials into the superconducting state.

Claims (10)

  1. An acoustic shockwave generator able to be driven electrically, which, as electrically conductive elements (5, 19; 49, 46), has a coil arrangement (5; 49) and a membrane (19; 46) able to be driven in an electrically impulsive manner by means of the coil arrangement (5; 49), by means of which shockwaves are able to be introduced into an acoustic propagation medium adjacent to the membrane (19; 46), characterised in that at least one of the electrically conductive elements (5, 19; 49, 46) contains material able to be transferred into the super-conducting state and in that means (9 to 16, 23 to 28; 23 to 26, 49, 51 to 54) are provided for transferring the material contained in at least one electrically conductive element into the super-conducting state.
  2. A shockwave generator according to claim 1, characterised in that the coil arrangement (5) is able to be transferred by means of a coolant into the super-conducting state, said coolant being located in the region of the coil arrangement (5).
  3. A shockwave generator according to claim 2, in which the coil arrangement (5) is fixed on a coil carrier (4), characterised in that the coil carrier (4) is provided with a channel (9, 10), through which the coolant flows past the coil arrangement (5).
  4. A shockwave generator according to claim 1, characterised in that the coil arrangement (49) is wound from a tube of a material able to be transferred into the super-conducting state and in that the coolant flows through the tube.
  5. A shockwave generator according to one of claims 1 to 4, characterised in that a coolant transferring the membrane (19; 46) into the superconducting state is provided as acoustic propagation medium, which is accommodated in a chamber arranged before the membrane.
  6. A shockwave generator according to claim 5, characterised in that the chamber accommodating the coolant is sealed on its end far from the membrane (19; 46) with a solid material plate (22), which is formed from a material conducting shockwaves, and in that the side of the solid material plate (22) facing away from the membrane (19; 46) is adjacent to a second chamber, in which there is located a shockwave-conducting medium, the temperature of which is higher than that of the coolant.
  7. A shockwave generator according to one of claims 1 to 6, characterised in that the coolant flows through the channel (9, 10) or the tube forming the coil arrangement (49) and/or the coolant flow/a through the chamber arranged in front of the membrane (5; 46) and/or the medium conducting shockwaves flows through the second chamber.
  8. A shockwave generator according to one of claims 1 to 7, characterised in that a partition wall (30) of material conducting shockwaves is provided, which seals the second chamber at its end removed from the solid material plate (22), wherein adjoining the side of the partition wall (30) facing away from the second chamber there is a material, the acoustic impedance of which corresponds substantially to that of an object (44) to be acoustically irradiated.
  9. A shockwave generator according to claim 8, characterised in that the partition wall is formed as an acoustic lens (30).
  10. A shockwave generator according to one of claims 1 to 9, characterised in that a flexible bag (3) is provided for acoustic coupling of the shockwave generator to a living being to be acoustically irradiated and in that adjoining the inner side of the bag (3) there is a material conducting shockwaves, the temperature of which does not vary substantially from the body temperature of the living being.
EP90111220A 1990-06-13 1990-06-13 Electrically-driven acoustic shock-wave generator Expired - Lifetime EP0461287B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP90111220A EP0461287B1 (en) 1990-06-13 1990-06-13 Electrically-driven acoustic shock-wave generator
DE59005639T DE59005639D1 (en) 1990-06-13 1990-06-13 Electrically driven acoustic shock wave generator.
US07/707,673 US5165388A (en) 1990-06-13 1991-05-30 Electrodynamic shockwave generator with a superconducting coil arrangement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP90111220A EP0461287B1 (en) 1990-06-13 1990-06-13 Electrically-driven acoustic shock-wave generator

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EP0461287A1 EP0461287A1 (en) 1991-12-18
EP0461287B1 true EP0461287B1 (en) 1994-05-04

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US5350352A (en) * 1991-02-21 1994-09-27 Siemens Aktiengesellschaft Acoustic pressure pulse generator
DE4132343C1 (en) * 1991-09-27 1992-12-10 Siemens Ag, 8000 Muenchen, De
DE102008034702A1 (en) * 2008-07-25 2010-01-28 Siemens Aktiengesellschaft Ultrasonic-shock wave head for patient during therapy i.e. lithotripsy, with shock waves, has electromagnetic shock wave source including electrical conductor arrangement having electrical conductor constructed from carbon-nano particles
CN101829012A (en) * 2010-05-11 2010-09-15 陈文韬 Surge pin
CN101904767B (en) * 2010-05-11 2015-11-25 朱伟辉 Shocking wave rod
CN101829009A (en) * 2010-05-11 2010-09-15 席贤兴 Surge hammer
US9833373B2 (en) 2010-08-27 2017-12-05 Les Solutions Médicales Soundbite Inc. Mechanical wave generator and method thereof
US20170195765A1 (en) * 2015-12-11 2017-07-06 Sebastian Koper Wearable device for conversation during high motion activity
US11883047B2 (en) * 2019-09-02 2024-01-30 Moshe Ein-Gal Electromagnetic shockwave transducer

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US3343035A (en) * 1963-03-08 1967-09-19 Ibm Superconducting electrical power transmission systems
US4048437A (en) * 1974-05-16 1977-09-13 The United States Energy Research And Development Administration Superconducting magnet cooling system
CH641290A5 (en) * 1978-12-22 1984-02-15 Bbc Brown Boveri & Cie METHOD FOR PRODUCING A SUPERAL CONDUCTOR, AND COIL PRODUCED BY THIS METHOD.
DE3328051A1 (en) * 1983-08-03 1985-02-14 Siemens AG, 1000 Berlin und 8000 München DEVICE FOR CONTACTLESS CRUSHING OF CONCRETE
JPS6220303A (en) * 1985-07-19 1987-01-28 Hitachi Ltd Forced-cooling superconducting coil apparatus
DE3789688D1 (en) * 1986-07-14 1994-06-01 Siemens Ag Shock wave generator for a device for the contactless smashing of concrements in the body of a living being.
DE8709363U1 (en) * 1987-07-07 1988-11-03 Siemens AG, 1000 Berlin und 8000 München Shock wave source
DE3742500A1 (en) * 1987-12-15 1989-06-29 Siemens Ag Shock wave generator for contactless destruction of concrements, and method for producing it
DE8801989U1 (en) * 1988-02-16 1989-06-15 Siemens AG, 1000 Berlin und 8000 München Shock wave generator for contactless crushing of concretions
US5057645A (en) * 1989-10-17 1991-10-15 Wisconsin Alumni Research Foundation Low heat loss lead interface for cryogenic devices

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EP0461287A1 (en) 1991-12-18
DE59005639D1 (en) 1994-06-09

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