WO2000074105A1 - X-ray tube and catheter having such an x-ray tube - Google Patents

X-ray tube and catheter having such an x-ray tube Download PDF

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Publication number
WO2000074105A1
WO2000074105A1 PCT/DE2000/001790 DE0001790W WO0074105A1 WO 2000074105 A1 WO2000074105 A1 WO 2000074105A1 DE 0001790 W DE0001790 W DE 0001790W WO 0074105 A1 WO0074105 A1 WO 0074105A1
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WO
WIPO (PCT)
Prior art keywords
ray tube
anode
catheter
ray
cathode
Prior art date
Application number
PCT/DE2000/001790
Other languages
German (de)
French (fr)
Inventor
Erich Hell
Mathias HÖRNIG
Manfred Pfeiler
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO2000074105A1 publication Critical patent/WO2000074105A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1001—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy using radiation sources introduced into or applied onto the body; brachytherapy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/32—Tubes wherein the X-rays are produced at or near the end of the tube or a part thereof which tube or part has a small cross-section to facilitate introduction into a small hole or cavity
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N5/1001—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy using radiation sources introduced into or applied onto the body; brachytherapy
    • A61N5/1002—Intraluminal radiation therapy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/08—Targets (anodes) and X-ray converters
    • H01J2235/086—Target geometry

Definitions

  • the invention relates to an X-ray tube with an anode and a cathode.
  • the invention also relates to a catheter provided for insertion into the human vascular system with such an x-ray tube.
  • PTCA percutaneous transluminal coronary angioplasty
  • the use of stents can somewhat reduce the number of cases in which restenosis forms: nevertheless, a treatment method which has allowed a significant further reduction in the formation of restenosis would achieve substantial benefits for the patient. namely, in addition to the avoidance of conventional and surgical follow-up interventions, even in a difficult starting situation, an extended stenosis-free interval and thus an improved quality of life.
  • Range of the high-energy radioactive radiation sources used are not to be carried out in the same clinical environment in which the PTCA takes place.
  • a catheter containing a miniaturized x-ray tube to perform radiation therapy of vascular wan ⁇ en with X-rays, as described in WO 97/07740 AI.
  • the X-ray quanta in the area of the central axis are drawn using electrons that are generated by field emission or the polarization of ferroelectrics. With field emission, there is a risk that the field emission current m of a microtip on the cathode will lead to evaporation and breakdown in a vacuum if a critical current density is exceeded.
  • the x-ray tubes described also have the disadvantage that the x-ray radiation emanates from a point source lying on the central axis of the x-ray tube, which is associated with a drop in the x-ray dose along the longitudinal axis of the x-ray tube.
  • part of the X-ray radiation is absorbed by the materials in the catheter.
  • the X-ray radiation loses intensity until it strikes the tissue tissue, since its point of origin is relatively far away from the tissue tissue and the intensity of the X-ray radiation is inversely proportional to the distance between the tissue tissue and the point of origin of the X-ray radiation.
  • an X-ray tube with a vacuum housing in which an elongated cathode and an anode surrounding it are accommodated, the anode having at least essentially linear sections which are arranged at a distance from one another, the linear sections of the Anode preferably in the manner of a network, in the manner of a cage or in the manner of a coil and according to a preferred embodiment form close to the wall of the vacuum housing, ie are at least closer to the wall of the vacuum housing than to the cathode.
  • the anode which is made of a material with a high atomic number, thus represents a non-closed envelope system surrounding the cathode, which allows the X-ray radiation to be generated close to the tissue to be treated, so that the X-ray radiation is on its way the vascular tissue to be treated loses little intensity.
  • the anode in the case of the X-ray tube according to the invention is not a transmission anode, but rather an anode composed of linear cut-offs. This is understood to mean “that the line-shaped sections have such a small width that only the smaller part of the envelope surface of the arode is formed by the line-shaped sections.
  • the line-shaped sections are less than 50%, but preferably a maximum of 10 - make out the envelope of the anode.
  • a catheter for insertion into the human vascular system which for treating vascular walls with X-rays contains at its distal end an X-ray tube of the type described above and which is preferably flexible for easier application
  • the catheter is provided in the region of the X-ray tube, but outside the main propagation path of the X-ray radiation emanating from the anode, with several inflatable balloons arranged at angular intervals, which are dimensioned such that when the catheter is inserted into a vessel, between adjacent inflated balloons a flow path for blood remains free.
  • the protein of the blood is prevented from curdling because of the not inconsiderable outside temperature of the catheter, since at least a reduced blood flow takes place through the flow paths located between adjacent inflated balloons.
  • Fig. 1 shows an inventive X-ray tube m schematic, partially block diagram-like representation in longitudinal section as part of an inventive
  • FIG. 2 shows a cross section through the catheter according to FIG. 1,
  • FIG. 3 shows a further exemplary embodiment in a representation analogous to FIG. 1, Fig. 4, the anode of the X-ray tube shown in FIG. 3 m Perspecti ⁇ vischer representation, and
  • the x-ray tube according to the invention designated overall by 1 in FIG. 1, has, according to FIG. 1, a vacuum housing 2, preferably of at least substantially rotationally symmetrical design, of lenticular shape, which has an outer diameter of, for example, 4 mm and is made of an X-ray-transparent material with a low atomic number, for example boron nitride or titanium.
  • An elongated thermal cathode designated as a whole by 3, is inserted into the vacuum housing 2 and has a length of e.g. 1 to 10 mm and the longitudinal axis of which at least approximately coincides with the longitudinal axis of the vacuum housing 2 and thus the longitudinal axis of the X-ray tube.
  • the two connections of the cathode 3 are led to the outside in a vacuum-tight manner by insulators from the vacuum housing 2.
  • a straight filament for example made of tungsten
  • cathode 3 a straight filament, for example made of tungsten
  • an elongated glow cathode can also be provided within the scope of the invention.
  • An anode 4 made of an X-ray-emissive anode material with a high atomic number is provided inside the vacuum housing 2, which surrounds the cathode 3 on all sides and is supported in that it rests on the inside of the vacuum housing 2, whereby the vacuum housing 2 assumes the same potential as the anode 4.
  • the anode 4 has at least essentially line-shaped sections which are arranged at a distance from one another, 1 in the case of the exemplary embodiment according to FIG. 1, the individual windings of a coil which is preferably circular in cross section and which is cylindrical in the case of the exemplary embodiment described are cylindrical. Since the diameter of the wire is small compared to the distance between adjacent turns of the coil, for example a ratio of 1: 3, the major part of the envelope surface of the anode 4 is free of anode material. The distance that the turns of the filament are from the inside of the vacuum housing is significantly less than their distance from the cathode 3.
  • a high-voltage generator 5 is provided, which is connected to the x-ray tube 1 via a taxial cable 6.
  • the triaxial cable 6 has a monofilament inner conductor 7, which is surrounded by high-voltage insulation 8, which separates it from a center conductor 9, which is known per se as a wire mesh or a helically wound foil strip.
  • the center conductor 9 is also surrounded by high-voltage insulation 10, which separates it from an outer conductor 11, which is likewise designed in a manner known per se as a wire mesh or a helically wound foil strip.
  • the X-ray tube 2 is embedded in a high-voltage insulation, X-ray-transparent insulating material body 12, which is formed from a suitable X-ray-transparent material.
  • the X-ray tube 1 forms a catheter K with the triaxial cable 6 and the insulating body 12, which catheter K is made of a biocompatible, i.e. physiologically well-tolerated material, e.g. Silicone, is coated.
  • catheter K is made of a biocompatible, i.e. physiologically well-tolerated material, e.g. Silicone, is coated.
  • the Isolierstoffkorper 12 is completely surrounded by the outer conductor 11 of the T ⁇ axialtent 6, which for safety of the patient is connected to a protective potential 9, since the tube tension is of the order of 20 kV, corresponding to an average energy of the X-ray quanta of 10 keV, and the catheter may end up in the patient's heart.
  • the X-ray tube 1 is thereby subjected to high voltage, i.e. with the tube voltage, applied that a pole of the high voltage generator 5 via the inner conductor 7 of the T ⁇ axialkul 6 with one connection of the cathode 3 and the other pole of the high voltage generator 5 via the central conductor 9 of the triaxial cable 6 with the anode 3, which for this purpose has a vacuum-tight connection led out of the vacuum housing 2 through one of the insulators.
  • the heating current required for the operation of the X-ray tube 1 for the cathode 3 is superimposed on the tube voltage, which is a DC voltage, as a preferably high-frequency AC voltage.
  • a modulator 14 is connected to the high-voltage generator 5.
  • the anode 4 is connected to the second connection of the cathode 3 via a capacitor 15.
  • the capacitor 15 prevents a direct current flowing through it between the anode 4 and the cathode 3, but, on the other hand, is dimensioned taking into account the frequency at which the modulator 14 operates so that it allows the flow of the heating current through the cathode 3 .
  • the cathode 3 During operation of the X-ray tube 1, the cathode 3 thus emits electrons over its entire length, which due to the electric field between the anode 4 and the cathode 3 are accelerated outwards in all directions and hit the line-shaped sections of the anode 4 and X-rays Draw (brake radiation) that emerges from the vacuum housing 2 of the X-ray tube 1 to the outside. Due to the use of an elongated cathode 3 on its Whole length is surrounded by the anode 4, the length of the cathode 3 and thus the longitudinal axis of the x-ray tube 1 result in an at least substantially uniform intensity distribution of the x-ray radiation, which is advantageous for the treatment of vessel walls.
  • the X-rays emanating from the anode 4 lose little intensity on their way to the tissue to be treated. Also due to the presence of the anode 4, there is no significant weakening of the intensity of the X-radiation, since, due to the fact that the anode 4 consists of linear sections, unlike in the case of a transmission anode, there is practically no weakening of the emitted X-rays by the anode 4 itself.
  • the catheter m shown in FIG. 1 has several, for example three, inflatable balloons 16 which are located close to the X-ray tube 1, if necessary, also shortly behind the X-ray tube 1, outside the main direction of propagation of the X-ray radiation emanating from the X-ray tube 1 on the lateral surface of the catheter, m offset at angular intervals.
  • the balloons 16 can be inflated via m channels not shown in the figures and, with a length of, for example, 2 to 4 mm, their cross-section m from FIG.
  • each of the balloons 16 extends over a range of approximately 60 °, so that a flow path remains free between adjacent balloons 16, which also extends over a range of approximately 60 °.
  • 3 and 4 differs from that previously described first in that the triaxial cable has a bifilar inner conductor with the two conductors 18a and 18b, which are connected to the two connections of the cathode 3, which in the case of the 3 and 4 is designed as a U-shaped curved glow wire.
  • a heating voltage generator 19, which is provided in addition to the high-voltage generator 5, is connected in a conventional manner to the other ends of the conductors 18a and 18b.
  • the negative pole of the high-voltage generator 5 is also connected to the conductor 18a.
  • the anode 4 m surrounding the cathode 3 m is designed as a cage which consists of a number of circular, line-shaped sections 20 and is composed of straight line-shaped sections 21, for example by welding, the sections 20 and 21 being formed from wire, preferably a circular cross section, m only a circular section and a straight section with the corresponding reference number in FIGS. 3 and 4 veins
  • FIG. 5 shows a further exemplary embodiment, which differs from the previously described plane in that the line-shaped sections of the anode 4 are wires, preferably circular in cross-section, which are connected to one another in the manner of a network, of which the m of FIG. 5 visible with the reference numerals 22 to 27.
  • the X-ray tube does not have to be accommodated in an insulating body 12, as in the case of the previously described exemplary embodiments, that of the outer conductor 11 and an outer skin 13 is surrounded. Rather, the vacuum housing of the X-ray tube can be formed from a biocompatible material, for example glass-like carbon, as it is sold under the name Sigradur®.
  • the outer skin 13 can be made removable. It is then possible to remove the outer skin 13 after use of the catheter and to replace it with a fresh, sterile outer skin 13, as a result of which the catheter is ready for use again.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Pathology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
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Abstract

The invention relates to an X-ray tube (1) having a vacuum casing (2) in which a long cathode (3) and an anode (4) surrounding the cathode are located. The anode (4) has at least substantially linear sections disposed at a distance from one another, wherein the linear sections of the anode (4) are disposed in the form of a net, a cage or a helix in the direct proximity of the wall of the vacuum casing (2).

Description

Beschreibungdescription
Röntgenröhre und Katheter mit einer solchen RöntgenröhreX-ray tube and catheter with such an X-ray tube
Die Erfindung betrifft eine Röntgenröhre mit einer Anode und einer Kathode. Die Erfindung betrifft außerdem einen zur Einfuhrung in das menschliche Gefaßsystem vorgesehenen Katheter mit einer solchen Röntgenröhre.The invention relates to an X-ray tube with an anode and a cathode. The invention also relates to a catheter provided for insertion into the human vascular system with such an x-ray tube.
Die PTCA (perkutane transluminale Coronar-Angioplastie) hat sich als Verfahren der Wahl zur Therapie von Stenosen durchgesetzt. Ein Problem dieses auch als Ballondilatation bekannten Verfahrens, das insbesondere im Bereicn der Herzkranzge- faße zum Einsatz kommt, liegt darin, daß es nach etwa einem halben Jahr m bis zu 50% aller Falle zu einer Restenosebil- dung durch Proliferation oder gar zu Lu enverschlussen kommt. Durch den Einsatz von Stents kann zwar die Anzahl der Falle, m denen sich Restenosen bilden, etwas reduziert: werden, dennoch wäre durch ein Behandlungsverfahren, das eine deutliche weitere Reduzierung der Bildung von Restenosen gestatten wurde, ein erneblicher Nutzen für den Patienten zu erreichen, nämlich neben der Vermeidung von mterventionellen und chirurgischen Folgeeingriffen auch bei schwieriger Ausgangslage ein verlängertes stenosefreies Intervall und damit eine verbesserte Lebensqualität.PTCA (percutaneous transluminal coronary angioplasty) has become the method of choice for the treatment of stenoses. A problem with this method, also known as balloon dilation, which is used in particular in the area of the coronary arteries, is that after about half a year m up to 50% of all cases lead to restenosis formation due to proliferation or even to occlusion is coming. The use of stents can somewhat reduce the number of cases in which restenosis forms: nevertheless, a treatment method which has allowed a significant further reduction in the formation of restenosis would achieve substantial benefits for the patient. namely, in addition to the avoidance of conventional and surgical follow-up interventions, even in a difficult starting situation, an extended stenosis-free interval and thus an improved quality of life.
Von den bisher untersuchten Verfahren führte nur die Behandlung des mittels PTCA therapierten Bereichs mit Gammastrahlung zu einer effektiven Reduktion der Bildung von Resteno- sen. Allerdings ist diese Behandlung aufgrund der hohenOf the procedures examined so far, only the treatment of the area treated with PTCA with gamma radiation led to an effective reduction in the formation of restenoses. However, this treatment is due to the high level
Reichweite der dabei verwendeten hochenergetischen radioaktiven Strahlungsquellen nicht n der gleichen klinischen Umgebung durchzufuhren, m der die PTCA stattfindet.Range of the high-energy radioactive radiation sources used are not to be carried out in the same clinical environment in which the PTCA takes place.
Ein weiterer vielversprechenαer Ansatz besteht m der Verwendung eines eine miniaturisierte Röntgenröhre enthaltenden Katheters zur Durchfuhrung einer Strahlentherapie von Gefäß- wanαen mit Röntgenstrahlung, wie dies in der WO 97/07740 AI besenrieben ist. Bei den hier bescnrieoenen Rontgenronren werden die Rontgenquanten im Bereich der Mittelachse mit Hilfe von Elektronen ausgelost, die durch Feldemission oder die Polarisation von Ferroelektrika erzeugt werden. Bei der Feldemission besteht die Gefahr, daß der Feldemissionsstrom m einer Mikrospitze auf der Kathode beim Überschreiten einer kritischen Stromdichte zu Verdampfungserscheinungen und Durchschlagen im Vakuum fuhrt. Die beschriebenen Rontgenroh- ren haben außerdem den Nachteil, daß die Röntgenstrahlung quasi von einer auf der Mittelachse der Röntgenröhre liegenden Punktquelle ausgeht, womit ein Abfall der Rontgendosis entlang der Längsachse der Röntgenröhre verbunden ist. Es kommt hinzu, daß ein Teil der Röntgenstrahlung m den im Ka- theter befindlichen Materialien absorbiert wird. Außerdem verliert die Röntgenstrahlung bis zum Auftreffen auf das Gefaßgewebe an Intensität, da ihr Entstehungsort relativ weit von dem Gefaßgewebe entfernt ist und die Intensität der Röntgenstrahlung dem Abstand zwischen Gefaßgewebe und Entste- hungsort der Röntgenstrahlung umgekehrt proportional ist.Another promising approach is to use a catheter containing a miniaturized x-ray tube to perform radiation therapy of vascular wanαen with X-rays, as described in WO 97/07740 AI. In the X-ray cartridges described here, the X-ray quanta in the area of the central axis are drawn using electrons that are generated by field emission or the polarization of ferroelectrics. With field emission, there is a risk that the field emission current m of a microtip on the cathode will lead to evaporation and breakdown in a vacuum if a critical current density is exceeded. The x-ray tubes described also have the disadvantage that the x-ray radiation emanates from a point source lying on the central axis of the x-ray tube, which is associated with a drop in the x-ray dose along the longitudinal axis of the x-ray tube. In addition, part of the X-ray radiation is absorbed by the materials in the catheter. In addition, the X-ray radiation loses intensity until it strikes the tissue tissue, since its point of origin is relatively far away from the tissue tissue and the intensity of the X-ray radiation is inversely proportional to the distance between the tissue tissue and the point of origin of the X-ray radiation.
In der US Re . 34 421 ist eine Röntgenröhre für onkologische Anwendungen beschrieben, bei der αie Rontgenquanten an der Innenseite eines röhrenförmigen Glasgehauses erzeugt werden. Als Elektronenquelle wird eine im Bereich der Mittelachse der Anordnung angebrachte langgestreckte Wendel verwendet, durch die ein Heizstrom fließt. Derartige Röntgenröhren lassen sich nur mit einem relativ großen Durchmesser realisieren, der den Einsatz solcher Röntgenröhren m kleineren Herzkranzgefaßen (Durchmesser z.B. 1,5 mm) praktisch ausschließt.In the US Re. 34 421 describes an X-ray tube for oncological applications in which the X-ray quanta are generated on the inside of a tubular glass housing. An elongated coil, through which a heating current flows, is used as the electron source in the region of the central axis of the arrangement. Such X-ray tubes can only be realized with a relatively large diameter, which practically excludes the use of such X-ray tubes in smaller coronary arteries (diameter e.g. 1.5 mm).
Aus der US Re . 34 421 ist es auch bekannt, eine langgestreckte Kathode isozentrisch innerhalb eines Vakuumgehauses anzuordnen, dessen Wandung als Durchstrahlanode ausgebildet ist. Infolge dieser Ausbildung der Anode kann die Röntgenstrahlung m ihrer Intensität m unerw nschter Weise geschwächt werden. Der Emndung liegt die Aufgaoe zugrunde, eine Röntgenröhre der eingangs genannten Art so auszubilden, daß gunstige Voraussetzungen für den Einsatz der Röntgenröhre im menschlichen Gefaßsystem gegeben sind. Der Erfindung liegt außerdem die Aufgaoe zugrunde, einen Katheter der eingangs genannten Art anzugeben, der die Voraussetzungen dafür bietet, mit einem besonders geringen Durchmesser realisiert zu werden.From the US Re. 34 421 it is also known to arrange an elongate cathode isocentrically within a vacuum housing, the wall of which is designed as a transmission anode. As a result of this design of the anode, the intensity of the X-radiation can be undesirably weakened. The mouth is based on the task of designing an X-ray tube of the type mentioned at the outset in such a way that favorable conditions are met for the use of the X-ray tube in the human vascular system. The invention is also based on the problem of specifying a catheter of the type mentioned at the beginning, which offers the prerequisites for being realized with a particularly small diameter.
Nach der Erfindung wird der eine Röntgenröhre betreffendeAccording to the invention, the one relating to an X-ray tube
Teil der Aufgabe gelost durch eine Röntgenröhre mit einem Va- kuumgehause, m dem eine langgestreckte Kathode und eine diese umgebende Anode aufgenommen sind, wobei die Anode wenigstens im wesentlichen linienformige Abschnitte aufweist, die im Abstand zueinander angeordnet sind, wobei die linien- formigen Abschnitte der Anode vorzugsweise nach Art eines Netzes, nach Art eines Käfigs oder nach Art einer Wendel und gemäß einer bevorzugten Ausfuhrungs form dicht bei der Wandung des Vakuumgehauses, d.h. zumindest naher bei der Wandung des Vakuumgehauses als bei der Kathode, angeordnet sind.Part of the task solved by an X-ray tube with a vacuum housing, in which an elongated cathode and an anode surrounding it are accommodated, the anode having at least essentially linear sections which are arranged at a distance from one another, the linear sections of the Anode preferably in the manner of a network, in the manner of a cage or in the manner of a coil and according to a preferred embodiment form close to the wall of the vacuum housing, ie are at least closer to the wall of the vacuum housing than to the cathode.
Die Anode, die aus einem Material hoher Kernladungszahl her- gestel_t ist, stellt also ein die Kathode umgebendes, nicht geschlossenes Hullsystem dar, das es gestattet, die Rontgen- strahlαng nahe am zu behandelnden Gefaßgewebe zu erzeugen, so daß d-e Röntgenstrahlung auf ihrem Weg zu dem zu behandelnden Gefaßgewebe nur wenig an Intensität verliert. In diesem Zu- sammer.nang ist auch von Bedeutung, daß es sich bei der Anode im Fal_e der erfmdungsgemäßen Röntgenröhre nicht um eine Durchstrahlanode handelt, sonαern um eine aus linienformigen Abschr._tten zusammengesetzte Anode. Hierunter soll verstanden werde", daß die linienformigen Abschnitte eine so geringe Breite aufweisen, daß nur der geringere Teil der Hullflache der Ar ode durch die linienformigen Abschnitte gebildet ist. Daß ne ßt, daß die linienformigen Abschnitte weniger als 50%, vorzugsweise aber maximal 10- der Hullflache der Anode ausmachen . Der einen Katheter betreffende Teil der Aufgabe wird nach der Erfindung gelost durch einen Katheter zur Einfuhrung m das menschliche Gefaßsystem, welcher zur Behandlung von Gefaßwan- den mit Röntgenstrahlung an seinem distalen Ende einer Röntgenröhre der vorstehend beschriebenen Art enthalt und welcher vorzugsweise zur leichteren Applikation flexibel ausgeführtThe anode, which is made of a material with a high atomic number, thus represents a non-closed envelope system surrounding the cathode, which allows the X-ray radiation to be generated close to the tissue to be treated, so that the X-ray radiation is on its way the vascular tissue to be treated loses little intensity. In this context, it is also important that the anode in the case of the X-ray tube according to the invention is not a transmission anode, but rather an anode composed of linear cut-offs. This is understood to mean "that the line-shaped sections have such a small width that only the smaller part of the envelope surface of the arode is formed by the line-shaped sections. That means that the line-shaped sections are less than 50%, but preferably a maximum of 10 - make out the envelope of the anode. The part of the task relating to a catheter is achieved according to the invention by a catheter for insertion into the human vascular system, which for treating vascular walls with X-rays contains at its distal end an X-ray tube of the type described above and which is preferably flexible for easier application
Gemäß einer bevorzugten Ausfuhrungsform der Erfindung ist der Katheter im Bereich der Röntgenröhre, jedoch außerhalb des Hauptausbreitungsweges der von der Anode ausgehenden Röntgenstrahlung mit mehreren in Winkelabstanden versetzt zueinander angeordneten aufblasbaren Ballons versehen, welche derart be- messen sind, daß bei in ein Gefäß eingeführtem Katheter zwischen benachbarten aufgeblasenen Ballons ein Stromungsweg für Blut frei bleibt. Auf diese Weise ist einerseits eine Zentrierung des Katheters im Gefaßlumen möglich. Andererseits wird verhindert, daß das Eiweiß des Blutes wegen der nicht unbeträchtlichen Außentemperatur des Katheters gerinnt, da zumindest ein reduzierter Blutfluß durch die zwischen benachbarten aufgeblasenen Ballons befindlichen Stromungswege erfolgt.According to a preferred embodiment of the invention, the catheter is provided in the region of the X-ray tube, but outside the main propagation path of the X-ray radiation emanating from the anode, with several inflatable balloons arranged at angular intervals, which are dimensioned such that when the catheter is inserted into a vessel, between adjacent inflated balloons a flow path for blood remains free. In this way, centering of the catheter in the vessel lumen is possible on the one hand. On the other hand, the protein of the blood is prevented from curdling because of the not inconsiderable outside temperature of the catheter, since at least a reduced blood flow takes place through the flow paths located between adjacent inflated balloons.
Ausfuhrungsbeispiele der Erfindung sind m den beigefugten Zeichnungen dargestellt. Es zeigen:Exemplary embodiments of the invention are shown in the accompanying drawings. Show it:
Fig. 1 eine erfmdungsgemaße Röntgenröhre m schematischer, teilweise blockschaltbildartiger Darstellung im Längsschnitt als Bestandteil eines erfmdungsgemaßenFig. 1 shows an inventive X-ray tube m schematic, partially block diagram-like representation in longitudinal section as part of an inventive
Katheters,Catheters,
Fig. 2 einen Querschnitt durch den Katheter gemäß Fig. 1,2 shows a cross section through the catheter according to FIG. 1,
Fig. 3 in zu der Fig. 1 analoger Darstellung ein weiteres Ausfuhrungsbeispiel, Fig. 4 die Anode der Röntgenröhre gemäß Fig. 3 m perspekti¬ vischer Darstellung, und3 shows a further exemplary embodiment in a representation analogous to FIG. 1, Fig. 4, the anode of the X-ray tube shown in FIG. 3 m Perspecti ¬ vischer representation, and
Fig. 5 m Form einer teilweisen Abwicklung die Anode einer weiteren Variante einer erfmdungsgemaßen Röntgenröhre .5 m in the form of a partial development of the anode of a further variant of an X-ray tube according to the invention.
Die m Fig. 1 insgesamt mit 1 bezeichnete erfmdungsgemaße Röntgenröhre weist gemäß Fig. 1 ein vorzugsweise wenigstens im wesentlichen rotationssymmetrisch ausgebildetes Vakuumge- hause 2 von ulsenformiger Gestalt auf, das einen Außendurchmesser von beispielsweise 4 mm hat und aus einem rontgen- transparenten Werkstoff geringer Kernladungszahl, beispielsweise Bornitrit oder Titan, hergestellt ist. In das Vakuumge- hause 2 ist eine insgesamt mit 3 bezeichnete langgestreckte thermische Kathode eingesetzt, die eine Lange von z.B. 1 bis 10 mm aufweist und deren Langsachse zumindest annähernd mit der Längsachse des Vakuumgehauses 2 und damit der Langsachse der Röntgenröhre übereinstimmt. Die beiden Anschlüsse der Ka- thode 3 sind vakuumdicht durch Isolatoren aus dem Vakuumge- hause 2 nach außen gefuhrt.The x-ray tube according to the invention, designated overall by 1 in FIG. 1, has, according to FIG. 1, a vacuum housing 2, preferably of at least substantially rotationally symmetrical design, of lenticular shape, which has an outer diameter of, for example, 4 mm and is made of an X-ray-transparent material with a low atomic number, for example boron nitride or titanium. An elongated thermal cathode, designated as a whole by 3, is inserted into the vacuum housing 2 and has a length of e.g. 1 to 10 mm and the longitudinal axis of which at least approximately coincides with the longitudinal axis of the vacuum housing 2 and thus the longitudinal axis of the X-ray tube. The two connections of the cathode 3 are led to the outside in a vacuum-tight manner by insulators from the vacuum housing 2.
Als Kathode 3 ist im Falle des dargestellten Ausfuhrungsbei- spiels ein gerader, beispielsweise aus Wolfram, hergestellter Gluhdraht vorgesehen. Anstelle eines geraden Gluhdrahtes kann im Rahmen der Erfindung jedoch auch eine aus Draht wendelartig gewundene langgestreckte Gluhkathode vorgesehen sein.In the case of the exemplary embodiment shown, a straight filament, for example made of tungsten, is provided as cathode 3. Instead of a straight glow wire, however, an elongated glow cathode can also be provided within the scope of the invention.
Innerhalb des Vakuumgehauses 2 ist eine Anode 4 aus einem rontgenemissiven Anodenmaterial hoher Kernladungszahl vorgesehen, die die Kathode 3 allseits umgibt und dadurch gehaltert ist, daß sie an der Innenseite des Vakuumgehauses 2 anliegt, wodurch das Vakuumgehause 2 das gleiche Potential wie die Anode 4 annimmt.An anode 4 made of an X-ray-emissive anode material with a high atomic number is provided inside the vacuum housing 2, which surrounds the cathode 3 on all sides and is supported in that it rests on the inside of the vacuum housing 2, whereby the vacuum housing 2 assumes the same potential as the anode 4.
Die Anode 4 weist wenigstens im wesentlichen linienformige Abschnitte auf, die im Abstand zueinander angeordnet sind, bei denen es sich im Falle des Ausfuhrungsbeispiels gemäß Fig. 1 um αie einzelnen Windungen einer aus Draht vorzugsweise kreisförmigen Querschnitts gewundene im Falle des beschriebenen Ausfuhrungsbeispiels zylindrische Wendel handelt. Da der Durchmesser des Drahtes klein gegen den Abstand benachbarter Windungen αer Wendel ist, z.B. Verhältnis 1:3, ist der überwiegende Teil der Hullflache der Anode 4 frei von Anodenmaterial. Der Abstand, den die Windungen der Wendel von der Innenseite des Vakuumgehauses aufweisen ist wesentlich geringer als ihr Abstand von der Kathode 3.The anode 4 has at least essentially line-shaped sections which are arranged at a distance from one another, 1 in the case of the exemplary embodiment according to FIG. 1, the individual windings of a coil which is preferably circular in cross section and which is cylindrical in the case of the exemplary embodiment described are cylindrical. Since the diameter of the wire is small compared to the distance between adjacent turns of the coil, for example a ratio of 1: 3, the major part of the envelope surface of the anode 4 is free of anode material. The distance that the turns of the filament are from the inside of the vacuum housing is significantly less than their distance from the cathode 3.
Um die Röntgenröhre 1 mit den zu deren Betrieb erforderlichen Spannungen und Strömen versorgen zu können, ist ein Hochspannungsgenerator 5 vorgesehen, der mit der Röntgenröhre 1 über ein Tπaxialkabel 6 verbunden ist. Das Triaxialkabel 6 weist einen monofllaren Innenleiter 7 auf, der von einer Hochspannungsisolation 8 umgeben ist, die ihn von einem m an sich bekannter Weise als Drahtgeflecht oder schraubenförmig aufgewickeltes Folienband ausgeführten Mittelleiter 9 trennt. Auch der Mittelleiter 9 ist von einer Hochspannungsisolation 10 umgeben, die ihn von einem Außenleiter 11 trennt, der ebenfalls m an sich bekannter Weise als Drahtgeflecht oder schraubenförmig aufgewickeltes Folienband ausgeführt ist.In order to be able to supply the x-ray tube 1 with the voltages and currents required for its operation, a high-voltage generator 5 is provided, which is connected to the x-ray tube 1 via a taxial cable 6. The triaxial cable 6 has a monofilament inner conductor 7, which is surrounded by high-voltage insulation 8, which separates it from a center conductor 9, which is known per se as a wire mesh or a helically wound foil strip. The center conductor 9 is also surrounded by high-voltage insulation 10, which separates it from an outer conductor 11, which is likewise designed in a manner known per se as a wire mesh or a helically wound foil strip.
Die Röntgenröhre 2 ist m einen der Hochspannungs-Isolierung dienenden, rontgentransparenten Isolierstoffkorper 12 eingebettet, der aus einem geeigneten rontgentransparenten Material gebildet ist.The X-ray tube 2 is embedded in a high-voltage insulation, X-ray-transparent insulating material body 12, which is formed from a suitable X-ray-transparent material.
Es wird also deutlich, daß die Röntgenröhre 1 mit dem Triaxialkabel 6 und dem Isolierstoffkorper 12 einen Katheter K bildet, der mit einer flexiblen, elektrisch isolierenden Außenhaut 13 aus einem biokompatiblen, d.h. physiologisch gut vertraglichen Material, z.B. Silikon, überzogen ist.It is therefore clear that the X-ray tube 1 forms a catheter K with the triaxial cable 6 and the insulating body 12, which catheter K is made of a biocompatible, i.e. physiologically well-tolerated material, e.g. Silicone, is coated.
Der Isolierstoffkorper 12 ist übrigens von dem Außenleiter 11 des Tπaxialkabels 6 vollständig umgeben, der zur Sicherheit des Patienten mit einem Schutzpotential 9 verbunden ist, da die Rohrenspannung m αer Größenordnung von 20 kV, entsprechend einer mittleren Energie der Rontgenquanten von 10 keV, liegt und der Katheter unter Umstanden im Herzen des Patien- ten endet.Incidentally, the Isolierstoffkorper 12 is completely surrounded by the outer conductor 11 of the Tπaxialkabel 6, which for safety of the patient is connected to a protective potential 9, since the tube tension is of the order of 20 kV, corresponding to an average energy of the X-ray quanta of 10 keV, and the catheter may end up in the patient's heart.
Im einzelnen wird die Röntgenröhre 1 dadurch mit Hochspannung, d.h. mit der Rohrenspannung, beaufschlagt, daß ein Pol des Hochspannungsgenerators 5 über den Innenleiter 7 des Tπaxialkabels 6 mit dem einen Anschluß der Kathode 3 und der andere Pol des Hochspannungsgenerators 5 über den Mittelleiter 9 des Triaxialkabels 6 mit der Anode 3 verbunden, die zu diesem Zweck einen vakuumdicht durch einen der Isolatoren aus dem Vakuumgehause 2 herausgeführten Anschluß aufweist.Specifically, the X-ray tube 1 is thereby subjected to high voltage, i.e. with the tube voltage, applied that a pole of the high voltage generator 5 via the inner conductor 7 of the Tπaxialkabel 6 with one connection of the cathode 3 and the other pole of the high voltage generator 5 via the central conductor 9 of the triaxial cable 6 with the anode 3, which for this purpose has a vacuum-tight connection led out of the vacuum housing 2 through one of the insulators.
Der zum Betrieb der Röntgenröhre 1 außerdem erforderliche Heizstrom für die Kathode 3 ist der Rohrenspannung, bei der es sicn um eine Gleichspannung handelt, als vorzugsweise hochfrequente Wechselspannung uoerlagert. Dazu ist an den Hochspannungsgenerator 5 ein Modulator 14 angeschlossen. Um den Fluß des Heizstromes durch die Kathode 3 zu ermöglichen, ist die Anode 4 über einen Kondensator 15 mit dem zweiten Anschluß der Kathode 3 verbunden. Der Kondensator 15 verhindert zwar, daß über ihn ein Gleichstrom zwischen der Anode 4 und der Kathode 3 fließt, ist aber andererseits unter Berücksichtigung der Frequenz, m t der der Modulator 14 arbeitet, derart bemessen, daß er den Fluß des Heizstroms durch die Kathode 3 gestattet.The heating current required for the operation of the X-ray tube 1 for the cathode 3 is superimposed on the tube voltage, which is a DC voltage, as a preferably high-frequency AC voltage. For this purpose, a modulator 14 is connected to the high-voltage generator 5. In order to allow the flow of the heating current through the cathode 3, the anode 4 is connected to the second connection of the cathode 3 via a capacitor 15. The capacitor 15 prevents a direct current flowing through it between the anode 4 and the cathode 3, but, on the other hand, is dimensioned taking into account the frequency at which the modulator 14 operates so that it allows the flow of the heating current through the cathode 3 .
Die Kathode 3 emittiert somit im Betrieb der Röntgenröhre 1 über hre gesamte Lange Elektronen, die infolge des zwischen der Anode 4 und der Katnode 3 vornandenen elektrischen Feldes m allen Richtungen raαial nach außen beschleunigt werden und dort auf die linienformigen Abschnitte der Anode 4 treffen und Röntgenstrahlung (Bremsstrahlung) auslosen, die aus dem Vakuumgehause 2 der Röntgenröhre 1 nach außen tritt. Infolge der Verwendung einer langgestreckten Kathode 3, die auf ihrer gesamten Lange von der Anode 4 umgeben ist, ergibt sich über die Lange der Kathode 3 und damit die Langsachse der Röntgenröhre 1 eine wenigstens im wesentlichen gleichmäßige Intensi- tatsverteilung der Röntgenstrahlung, was für die Behandlung von Gefaßwanden gunstig ist. Infolge des Umstandes, daß sich die Windungen der Wendel der Kathode 3 dicht bei der Innenseite des Vakuumgehauses 2 befinden, verliert die von der Anode 4 ausgehende Röntgenstrahlung auf ihrem Weg zu dem jeweils zu behandelnden Gefaßgewebe nur wenig an Intensität. Auch infolge der Anwesenheit der Anode 4 tritt keine wesentliche Schwächung der Intensität der Röntgenstrahlung auf, da infolge des Umstandes, daß die Anode 4 aus linienformigen Abschnitten besteht, anders als im Falle einer Durchstrahlanode praktisch keine Schwächung der emittierten Röntgenstrahlung durch die Anode 4 selbst erfolgt.During operation of the X-ray tube 1, the cathode 3 thus emits electrons over its entire length, which due to the electric field between the anode 4 and the cathode 3 are accelerated outwards in all directions and hit the line-shaped sections of the anode 4 and X-rays Draw (brake radiation) that emerges from the vacuum housing 2 of the X-ray tube 1 to the outside. Due to the use of an elongated cathode 3 on its Whole length is surrounded by the anode 4, the length of the cathode 3 and thus the longitudinal axis of the x-ray tube 1 result in an at least substantially uniform intensity distribution of the x-ray radiation, which is advantageous for the treatment of vessel walls. As a result of the fact that the turns of the helix of the cathode 3 are located close to the inside of the vacuum housing 2, the X-rays emanating from the anode 4 lose little intensity on their way to the tissue to be treated. Also due to the presence of the anode 4, there is no significant weakening of the intensity of the X-radiation, since, due to the fact that the anode 4 consists of linear sections, unlike in the case of a transmission anode, there is practically no weakening of the emitted X-rays by the anode 4 itself.
Um eine Zentrierung des Katheters im Lumen eines zu behandelnden Gefäßes zu ermöglichen und der Eiweißgerinnung des Blutes vorzubeugen, weist der Katheter m aus der Fig. 1 er- sichtlicher Weise mehrere, beispielsweise drei, aufblasbare Ballons 16 auf, die dicht vor der Röntgenröhre 1, bei Bedarf zusätzlich auch kurz hinter der Röntgenröhre 1, außerhalb der Hauptausbreitungsrichtung der von der Röntgenröhre 1 ausgehenden Röntgenstrahlung an der Mantelflache des Katheters m Winkelabstanden versetzt angeordnet sind. Die Ballons 16 können über m den Figuren nicht dargestellte Kanäle aufgeblasen werden und sind bei einer Lange von beispielsweise 2 bis 4 mm m ihrem Querschnitt m aus der Fig. 2 ersichtlicher Weise so bemessen, daß bei m ein Gefäß 17 eingeführtem Katheter K zwischen benachbarten aufgeblasenen Ballons 16 ein Stromungsweg für Blut frei bleibt. Dabei ist im Falle des vorliegenden Ausfuhrungsbeispiels in der aus Fig. 2 ersichtlichen Weise die Anordnung so getroffen, daß jeder der Ballons 16 sich über einen Wmkelbereich von ca. 60° erstreckt, so daß zwi- sehen benachbarten Ballons 16 jeweils ein Stromungsweg frei bleibt, der sich ebenfalls über einen Wmkelbereich von ca. 60° erstreckt. Das Ausfuhrungsbeispiel gemäß den Fig. 3 und 4 unterscheidet sich von dem zuvor beschriebenen zunächst dadurch, daß das Triaxialkabel einen bifilaren Innenleiter mit den beiden Lei- tern 18a und 18b aufweist, die mit den beiden Anschlüssen der Kathode 3 verbunden sind, die im Falle des Ausfuhrungsbeispiels gemäß αen Fig. 3 und 4 als U-formig gekrümmter Gluhdraht ausgeführt ist. Mit den anderen Enden der Leiter 18a und 18b ist m herkömmlicher Weise ein zusatzlich zu dem Hochspannungsgenerator 5 vorgesehener Heizspannungsgenerator 19 verbunden. An den Leiter 18a ist außerdem der negative Pol des Hochspannungsgenerators 5 angeschlossen.In order to enable the catheter to be centered in the lumen of a vessel to be treated and to prevent protein clotting of the blood, the catheter m shown in FIG. 1 has several, for example three, inflatable balloons 16 which are located close to the X-ray tube 1, if necessary, also shortly behind the X-ray tube 1, outside the main direction of propagation of the X-ray radiation emanating from the X-ray tube 1 on the lateral surface of the catheter, m offset at angular intervals. The balloons 16 can be inflated via m channels not shown in the figures and, with a length of, for example, 2 to 4 mm, their cross-section m from FIG. 2 can be seen such that, at m, a tube 17 inserted catheter K between adjacent inflated ones Balloons 16 a flow path for blood remains free. In the case of the present exemplary embodiment in the manner shown in FIG. 2, the arrangement is such that each of the balloons 16 extends over a range of approximately 60 °, so that a flow path remains free between adjacent balloons 16, which also extends over a range of approximately 60 °. 3 and 4 differs from that previously described first in that the triaxial cable has a bifilar inner conductor with the two conductors 18a and 18b, which are connected to the two connections of the cathode 3, which in the case of the 3 and 4 is designed as a U-shaped curved glow wire. A heating voltage generator 19, which is provided in addition to the high-voltage generator 5, is connected in a conventional manner to the other ends of the conductors 18a and 18b. The negative pole of the high-voltage generator 5 is also connected to the conductor 18a.
Als weiterer Unterschied des Ausfuhrungsbeispiels gemäß den Fig. 3 und 4 gegenüber dem zuvor beschriebenen ist zu nennen, daß die die Kathode 3 umgebende Anode 4 m insbesondere aus der Fig. 4 ersichtlichen Weise als Käfig ausgebildet ist, der aus einer Anzahl von kreisπngformigen linienformigen Abschnitten 20 und aus geradlinigen linienformigen Abschnitten 21 beispielsweise durch Schweißen zusammengesetzt ist, wobei die Abschnitte 20 und 21 aus Draht, vorzugsweise kreisförmigen Querschnitts, gebildet sind, wobei m den Fig. 3 und 4 nur jeweils ein kreisringformiger Abschnitt und ein geradliniger Abschnitt mit der entsprechenden Bezugsziffer versenenAs a further difference of the exemplary embodiment according to FIGS. 3 and 4 compared to the one described above, it should be mentioned that the anode 4 m surrounding the cathode 3 m, in particular from FIG. 4, is designed as a cage which consists of a number of circular, line-shaped sections 20 and is composed of straight line-shaped sections 21, for example by welding, the sections 20 and 21 being formed from wire, preferably a circular cross section, m only a circular section and a straight section with the corresponding reference number in FIGS. 3 and 4 veins
Die Fig. 5 zeigt ein weiteres Ausfuhrungsbeispiel, das sich von dem zuvor bescnπebenen dadurch unterscheidet, daß es sich bei den linienformigen Abschnitten der Anode 4 um nach Art eines Netzes miteinander verknüpfte Drahte von vorzugsweise kreisförmigen Querschnittes handelt, von denen die m der Fig. 5 sichtbaren mit den Bezugszeichen 22 bis 27 bezeichnet sind.FIG. 5 shows a further exemplary embodiment, which differs from the previously described plane in that the line-shaped sections of the anode 4 are wires, preferably circular in cross-section, which are connected to one another in the manner of a network, of which the m of FIG. 5 visible with the reference numerals 22 to 27.
Die Röntgenröhre muß nicht wie im Falle der zuvor beschπeoe- nen Ausfuhrungsbeispiele m einem Isolierstoffkorper 12 aufgenommen sein, der von dem Außenleiter 11 und einer Außenhaut 13 umgeben ist. Vielmehr kann das Vakuumgehause der Rontgen- ronre aus einem biokompatiblen Material, beispielsweise glasartigem Kohlenstoff, wie er unter der Bezeichnung Sigradur® vertrieben wird, gebildet sein. Um die Röntgenröhre 1 mit dem Triaxialkabel 6 mehrfach verwenden zu können, kann die Außenhaut 13 abnehmbar ausgeführt sein. Es ist dann möglich, nach Gebrauch des Katheters die Außenhaut 13 abzunehmen und durch eine frische, sterile Außenhaut 13 zu ersetzen, wodurch der Katheter wieder gebrauchsfertig wird.The X-ray tube does not have to be accommodated in an insulating body 12, as in the case of the previously described exemplary embodiments, that of the outer conductor 11 and an outer skin 13 is surrounded. Rather, the vacuum housing of the X-ray tube can be formed from a biocompatible material, for example glass-like carbon, as it is sold under the name Sigradur®. In order to be able to use the x-ray tube 1 with the triaxial cable 6 several times, the outer skin 13 can be made removable. It is then possible to remove the outer skin 13 after use of the catheter and to replace it with a fresh, sterile outer skin 13, as a result of which the catheter is ready for use again.
Um die Spannungsfestigkeit der Röntgenröhre 1 zu gewährleisten, kann es im Hinblick auf „High Voltage Vacuum Insula- tιonw, R.V. Latham, Academic Press, 1981, Seiten 130 bis 132, zweckmäßig sein, die Röntgenröhre 1 gepulst zu betreiben, wo- bei die erforderlichen Pulslangen im Bereich von einigen Nanosekunden liegen. In order to ensure the dielectric strength of the x-ray tube 1, it may be expedient to operate the x-ray tube 1 in a pulsed manner, with the view of “High Voltage Vacuum Insulation w , RV Latham, Academic Press, 1981, pages 130 to 132” required pulse lengths are in the range of a few nanoseconds.

Claims

Patentansprüche claims
1. Röntgenröhre mit einem Vakuumgehause, m dem eine langestreckte Kathode und eine diese umgebende Anode aufgenommen sind, wobei die Anode wenigstens im wesentlichen linienfor- mige Abschnitte aufweist die im Abstand zueinander angeordnet sind.1. X-ray tube with a vacuum housing, in which an elongated cathode and an anode surrounding it are accommodated, the anode having at least essentially line-shaped sections which are arranged at a distance from one another.
2. Röntgenröhre nach Anspruch 1, deren linienformige Ab- schnitte nach Art eines Netzes angeordnet sind.2. X-ray tube according to claim 1, the line-shaped sections of which are arranged in the manner of a network.
3. Röntgenröhre nach Anspruch 1, deren linienformige Abschnitte nach Art eines Käfigs angeordnet sind.3. X-ray tube according to claim 1, whose linear sections are arranged in the manner of a cage.
4. Röntgenröhre nach Anspruch 1, deren linienformige Abschnitte nach Art einer Wendel angeordnet sind.4. X-ray tube according to claim 1, whose line-shaped sections are arranged in the manner of a coil.
5. Röntgenröhre nach einem der Ansprüche 1 bis 4, deren linienformige Abschnitte dicht bei der Wandung des Vakuumgehauses angeordnet sind.5. X-ray tube according to one of claims 1 to 4, the line-shaped sections of which are arranged close to the wall of the vacuum housing.
6. Katheter zu Einfuhrung in das menschliche Gefäßsystem, welcher zur Behandlung von Gefaßwanden mit Röntgenstrahlung an seinem d stalen ende mit eine Röntgenröhre nach einem der Ansprüche 1 bis 4 enthalt.6. Catheter for insertion into the human vascular system, which contains an x-ray tube according to one of claims 1 to 4 for the treatment of vascular walls with x-rays at its d stal end.
7. Katheter nach Anspruch 6, welcher im Bereich αer Röntgenröhre, jedoch außerhalb des Hauptausbreitungswegs der von der Anode ausgehenden Röntgenstrahlung mit mehreren m Wmkelab- standen versetzt zueinander angeordneten aufblasbaren Ballons versehen ist, welche derart bemessen sind, daß bei in ein Gefäß eingeführtem Katheter zwischen benachbarten aufgeblasenen Ballons ein Stromungsweg für Blut frei bleibt.7. A catheter according to claim 6, which is provided in the region of the x-ray tube, but outside the main propagation path of the x-ray radiation emanating from the anode, with inflatable balloons arranged several m apart, which are dimensioned such that, when the catheter is inserted into a vessel, between adjacent inflated balloons a flow path for blood remains free.
8. Katheter nach Anspruch 1 oder 2, der flexibel ist. 8. The catheter of claim 1 or 2, which is flexible.
PCT/DE2000/001790 1999-06-02 2000-05-31 X-ray tube and catheter having such an x-ray tube WO2000074105A1 (en)

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FR2534066A1 (en) * 1982-10-05 1984-04-06 Thomson Csf X-RAY TUBE PRODUCING A HIGH-PERFORMANCE BEAM, ESPECIALLY IN THE FORM OF A BRUSH
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WO1997007740A1 (en) * 1995-08-24 1997-03-06 Interventional Innovations Corporation X-ray catheter

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US34421A (en) * 1862-02-18 Improvement in channeling-tools for harness-makers

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Publication number Priority date Publication date Assignee Title
GB357978A (en) * 1930-06-30 1931-09-30 Frederick Alexander Lindemann Improvements in x-ray tubes
DE1064649B (en) * 1956-04-07 1959-09-03 Licentia Gmbh Membrane anode tube
DE2358512A1 (en) * 1973-11-23 1975-06-05 Siemens Ag X-ray tube graphite disc anode - is produced by forming slots, tungsten coating and grinding to expose tungsten in slot bottoms
DE2421119A1 (en) * 1974-05-02 1975-11-13 Burns Stephen J X-ray tube with low divergence beam - has monocrystal anode with longitudinal recess forming X-ray emitting surfaces and electron accelerator
FR2534066A1 (en) * 1982-10-05 1984-04-06 Thomson Csf X-RAY TUBE PRODUCING A HIGH-PERFORMANCE BEAM, ESPECIALLY IN THE FORM OF A BRUSH
EP0187020A2 (en) * 1984-12-20 1986-07-09 Varian Associates, Inc. High-intensity X-ray source
USRE34421E (en) * 1990-11-21 1993-10-26 Parker William J X-ray micro-tube and method of use in radiation oncology
WO1997007740A1 (en) * 1995-08-24 1997-03-06 Interventional Innovations Corporation X-ray catheter

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