EP0279317A1 - X-ray diagnostic apparatus - Google Patents

X-ray diagnostic apparatus Download PDF

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Publication number
EP0279317A1
EP0279317A1 EP88101815A EP88101815A EP0279317A1 EP 0279317 A1 EP0279317 A1 EP 0279317A1 EP 88101815 A EP88101815 A EP 88101815A EP 88101815 A EP88101815 A EP 88101815A EP 0279317 A1 EP0279317 A1 EP 0279317A1
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EP
European Patent Office
Prior art keywords
ray tube
ray
circuit
thyristors
voltage
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP88101815A
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German (de)
French (fr)
Inventor
Jürgen Dipl.-Ing. Ussmüller (FH)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
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Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0279317A1 publication Critical patent/EP0279317A1/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/56—Switching-on; Switching-off

Definitions

  • the invention relates to an X-ray diagnostic device with an X-ray tube, a high-voltage generator and a switching device for switching the X-ray tube on and off.
  • the high-voltage generator of an X-ray diagnostic device generally consists of a high-voltage transformer with a rectifier and smoothing element downstream to reduce the high-voltage ripple.
  • a high-voltage cable which has a capacitance to earth, is used to couple the X-ray tube to the high-voltage generator.
  • the parallel connection of smoothing and cable capacitance must be charged. After the recording, the charge in this capacity is discharged via the X-ray tube by means of the current flowing in the X-ray tube.
  • the proportion of the effective patient dose which arises from the discharge of the capacity can be as large or larger than the proportion of the desired imaging dose. Accordingly, the patient is exposed to radiation that does not contribute to image generation.
  • the invention has for its object to provide an X-ray diagnostic device of the type mentioned in such a way that non-imaging, but patient exposure to radiation after switching off the high voltage is avoided by discharging the cable and smoothing capacity via the X-ray tube.
  • a thyristor circuit is connected in parallel to the X-ray tube, to which a control circuit for discharging the high-voltage side capacities is assigned after the end of an X-ray exposure and which is in series with an erase circuit for erase after unloading.
  • the thyristor circuit prevents or at least reduces the discharge current of the capacitors on the high-voltage side via the X-ray tube.
  • a high-voltage transformer 1 which feeds an X-ray tube 2 via a high-voltage rectifier 3.
  • a smoothing capacitance 4 lies parallel to the X-ray tube 2.
  • the high-voltage cables leading to the X-ray tube 2 have capacitances with respect to earth, which are denoted by 5.
  • the thyristors 7 are optically ignited by a control circuit 10 with the aid of optocouplers 11.
  • the thyristors 7 are ignited with the aid of the control circuit 10.
  • the high-voltage capacitors 4, 5 are discharged without the X-ray tube 2 being subjected to a significant discharge current.
  • the resistance value of the resistor 8 is to be dimensioned such that the discharge current is significantly higher than the X-ray tube current, e.g. is 10 to 100 times the X-ray tube current.
  • the erase circuit 9 has the effect that the thyristors 7 are securely locked again before the start of a new recording.
  • FIG. 2 shows the time profile of the x-ray tube voltage and FIG. 3 shows that of the x-ray tube current without the discharge circuit 6. It can be clearly seen that after completion of a recording at time t1, a relatively slowly decreasing discharge current due to discharge of the capacitors 4, 5 on the high-voltage side flows over the X-ray tube 2.
  • FIG. 4 shows the course of the X-ray tube voltage
  • FIG. 5 shows the course of the X-ray tube current with the discharge circuit 6. A significantly faster drop in the X-ray tube voltage and the X-ray tube current can be seen.
  • Fig. 6 shows the course of the discharge current in the discharge circuit 6, e.g. through the resistor 8.
  • FIG. 1 shows a switch S which is intended to represent schematically the switching device for switching the X-ray tube 2 on and off for the production of X-ray images. Furthermore, optical waveguides 12 are shown, which connect the optocouplers 11 to the thyristors 7.

Abstract

An X-ray diagnostic apparatus is intended to be designed such that the capacitors (4, 5) on the high-voltage side are not discharged, or are discharged to an only insignificant extent, via the X-ray tube (2), after an exposure has been completed. To this end, connected in parallel with the X-ray tube (2) there is a thyristor circuit (7) with which is associated a trigger circuit (10) for discharging the capacitors (4, 5) on the high-voltage side after an X-ray exposure has been completed, and which is connected in series with an extinguishing circuit (9) for extinguishing after the discharge. The thyristors (7) may be light-triggerable thyristors. The invention is particularly applicable for making brief X-ray exposures. <IMAGE>

Description

Die Erfindung betrifft eine Röntgendiagnostikeinrichtung mit einer Röntgenröhre, einem Hochspannungserzeuger und einer Schaltvorrichtung zum Ein- und Ausschalten der Röntgenröhre.The invention relates to an X-ray diagnostic device with an X-ray tube, a high-voltage generator and a switching device for switching the X-ray tube on and off.

Der Hochspannungserzeuger einer Röntgendiagnostikeinrichtung besteht in der Regel aus einem Hochspannungstransformator mit nachgeschaltetem Gleichrichter und Glättungsglied zur Reduzie­rung der Hochspannungswelligkeit. Zur Ankopplung der Röntgen­röhre an den Hochspannungserzeuger dient ein Hochspannungskabel, das eine Kapazität gegen Erde aufweist. Zu Beginn einer Rönt­genaufnahme muß also die Parallelschaltung aus Glättungs- und Kabelkapazität aufgeladen werden. Nach der Aufnahme wird die Ladung in dieser Kapazität über die Röntgenröhre mittels des in der Röntgenröhre fließenden Stromes entladen.The high-voltage generator of an X-ray diagnostic device generally consists of a high-voltage transformer with a rectifier and smoothing element downstream to reduce the high-voltage ripple. A high-voltage cable, which has a capacitance to earth, is used to couple the X-ray tube to the high-voltage generator. At the start of an X-ray, the parallel connection of smoothing and cable capacitance must be charged. After the recording, the charge in this capacity is discharged via the X-ray tube by means of the current flowing in the X-ray tube.

Bei hohen Röntgenröhrenspannungen, kurzen Aufnahmezeiten und kleinen Röntgenröhrenströmen kann der Anteil der wirksamen Pa­tientendosis, der durch die Entladung der Kapazität entsteht, genau so groß oder größer sein als der Anteil der gewollten bildgebenden Dosis. Der Patient wird demgemäß mit Strahlung be­lastet, die nicht zur Bilderzeugung beiträgt.With high x-ray tube voltages, short exposure times and small x-ray tube currents, the proportion of the effective patient dose which arises from the discharge of the capacity can be as large or larger than the proportion of the desired imaging dose. Accordingly, the patient is exposed to radiation that does not contribute to image generation.

Der Erfindung liegt die Aufgabe zugrunde, eine Röntgendiagno­stikeinrichtung der eingangs genannten Art so auszubilden, daß nicht bildgebende, aber Patienten belastende Strahlung nach dem Abschalten der Hochspannung durch die Entladung der Kabel- und Glättungskapazität über die Röntgenröhre vermieden ist.The invention has for its object to provide an X-ray diagnostic device of the type mentioned in such a way that non-imaging, but patient exposure to radiation after switching off the high voltage is avoided by discharging the cable and smoothing capacity via the X-ray tube.

Diese Aufgabe ist erfindungsgemäß dadurch gelöst, daß parallel zur Röntgenröhre eine Thyristorschaltung liegt, der eine An­steuerschaltung zum Entladen der hochspannungsseiten Kapazitä­ten nach Beendigung einer Röntgenaufnahme zugeordnet ist und die in Reihe mit einer Löschschaltung zum Löschen nach dem Ent­laden liegt. Bei der erfindungsgemäßen Röntgendiagnostikein­richtung wird durch die Thyristorschaltung der Entladestrom der hochspannungsseitigen Kapazitäten über die Röntgenröhre verhin­dert oder mindestens reduziert.This object is achieved in that a thyristor circuit is connected in parallel to the X-ray tube, to which a control circuit for discharging the high-voltage side capacities is assigned after the end of an X-ray exposure and which is in series with an erase circuit for erase after unloading. In the X-ray diagnostic device according to the invention, the thyristor circuit prevents or at least reduces the discharge current of the capacitors on the high-voltage side via the X-ray tube.

Die Erfindung ist nachfolgend anhand eines in der Zeichnung dargestellten Ausführungsbeispieles näher erläutert. Es zeigen:

  • Fig. 1 das Schaltbild einer Röntgendiagnostikeinrichtung nach der Erfindung, und
  • Fig. 2 bis 6 Kurven zur Erläuterung der Fig. 1.
The invention is explained below with reference to an embodiment shown in the drawing. Show it:
  • Fig. 1 shows the circuit diagram of an X-ray diagnostic device according to the invention, and
  • 2 to 6 curves for explaining Fig. 1st

In der Zeichnung ist ein Hochspannungstransformator 1 darge­stellt, der eine Röntgenröhre 2 über einen Hochspannungsgleich­richter 3 speist. Parallel zur Röntgenröhre 2 liegt eine Glät­tungskapazität 4. Die zur Röntgenröhre 2 führenden Hochspan­nungskabel weisen gegenüber Erde Kapazitäten auf, die mit 5 be­zeichnet sind.In the drawing, a high-voltage transformer 1 is shown, which feeds an X-ray tube 2 via a high-voltage rectifier 3. A smoothing capacitance 4 lies parallel to the X-ray tube 2. The high-voltage cables leading to the X-ray tube 2 have capacitances with respect to earth, which are denoted by 5.

Parallel zur Röntgenröhre 2 ist ein Entladekreis 6 mit mehreren in Reihe zueinander geschalteten Thyristoren 7, einem Entlade­widerstand 8 und einem Löschkreis 9 geschaltet. Die Thyristoren 7 werden von einer Ansteuerschaltung 10 mit Hilfe von Optokopp­lern 11 optisch gezündet.A discharge circuit 6 with a plurality of thyristors 7 connected in series with one another, a discharge resistor 8 and an extinguishing circuit 9 is connected in parallel with the X-ray tube 2. The thyristors 7 are optically ignited by a control circuit 10 with the aid of optocouplers 11.

Unmittelbar nach Beendigung einer Aufnahme erfolgt die Zündung der Thyristoren 7 mit Hilfe der Ansteuerschaltung 10. Dadurch werden die hochspannungsseitigen Kapazitäten 4, 5 entladen, ohne daß die Röntgenröhre 2 mit einem wesentlichen Entladestrom beaufschlagt wird. Der Widerstandswert des Widerstandes 8 ist so zu bemessen, daß der Entladestrom deutlich höher als der Röntgenröhrenstrom ist, z.B. das 10- bis 100fache des Röntgen­röhrenstromes beträgt.Immediately after the end of a recording, the thyristors 7 are ignited with the aid of the control circuit 10. As a result, the high-voltage capacitors 4, 5 are discharged without the X-ray tube 2 being subjected to a significant discharge current. The resistance value of the resistor 8 is to be dimensioned such that the discharge current is significantly higher than the X-ray tube current, e.g. is 10 to 100 times the X-ray tube current.

Die Löschschaltung 9 bewirkt, daß die Thyristoren 7 vor Beginn einer neuen Aufnahme sicher wieder gesperrt sind.The erase circuit 9 has the effect that the thyristors 7 are securely locked again before the start of a new recording.

Die Fig. 2 zeigt den zeitlichen Verlauf der Röntgenröhrenspan­nung und die Fig. 3 den des Röntgenröhrenstromes ohne den Ent­ladekreis 6. Es ist deutlich erkennbar, daß nach Beendigung ei­ner Aufnahme im Zeitpunkt t1 noch ein relativ langsam abfallen­der Entladestrom durch Entladung der hochspannungsseitigen Kapa­zitäten 4, 5 über die Röntgenröhre 2 fließt. Im Gegensatz hier­zu zeigt die Fig. 4 den Verlauf der Röntgenröhrenspannung und die Fig. 5 den Verlauf des Röntgenröhrenstromes mit dem Entla­dekreis 6. Es ist ein deutlich schnellerer Abfall der Röntgen­röhrenspannung und des Röntgenröhrenstromes erkennbar. Die Fig. 6 zeigt den Verlauf den Entladestromes im Entladekreis 6, z.B. durch den Widerstand 8.2 shows the time profile of the x-ray tube voltage and FIG. 3 shows that of the x-ray tube current without the discharge circuit 6. It can be clearly seen that after completion of a recording at time t1, a relatively slowly decreasing discharge current due to discharge of the capacitors 4, 5 on the high-voltage side flows over the X-ray tube 2. In contrast to this, FIG. 4 shows the course of the X-ray tube voltage and FIG. 5 shows the course of the X-ray tube current with the discharge circuit 6. A significantly faster drop in the X-ray tube voltage and the X-ray tube current can be seen. Fig. 6 shows the course of the discharge current in the discharge circuit 6, e.g. through the resistor 8.

In der Fig. 1 ist ein Schalter S dargestellt, der schematisch die Schaltvorrichtung zum Ein- und Ausschalten der Röntgenröhre 2 für die Anfertigung von Röntgenaufnahmen darstellen soll. Ferner sind noch Lichtwellenleiter 12 gezeigt, die die Opto­koppler 11 mit den Thyristoren 7 verbinden.1 shows a switch S which is intended to represent schematically the switching device for switching the X-ray tube 2 on and off for the production of X-ray images. Furthermore, optical waveguides 12 are shown, which connect the optocouplers 11 to the thyristors 7.

Claims (2)

1. Röntgendiagnostikeinrichtung mit einer Röntgenröhre (2), ei­nem Hochspannungserzeuger (1, 3, 4) und einer Schaltvorrichtung (S) zum Ein- und Ausschalten der Röntgenröhre (2), da­durch gekennzeichnet, daß parallel zur Röntgenröhre (2) eine Thyristorschaltung (7) liegt, der eine Ansteuerschaltung (10) zum Entladen der hochspannungsseitigen Kapazitäten (4, 5) nach Beendigung einer Röntgenaufnahme zuge­ordnet ist und die in Reihe mit einer Löschschaltung (9) zum Löschen nach der Entladung liegt.1. X-ray diagnostic device with an X-ray tube (2), a high voltage generator (1, 3, 4) and a switching device (S) for switching the X-ray tube (2) on and off, characterized in that a thyristor circuit (7 ) which is assigned a control circuit (10) for discharging the high-voltage capacitors (4, 5) after the end of an X-ray exposure and which is in series with an erase circuit (9) for erasing after the discharge. 2. Röntgendiagnostikeinrichtung nach Anspruch 1, da­durch gekennzeichnet, daß die Thyristoren (7) lichtzündbare Thyristoren sind und daß der Ansteuerschal­tung (10) Optokoppler (11) zugeordnet sind, von denen Lichtwel­lenleiter (12) zu den Thyristoren (7) führen.2. X-ray diagnostic device according to claim 1, characterized in that the thyristors (7) are light-ignitable thyristors and that the control circuit (10) are associated with optocouplers (11), of which optical fibers (12) lead to the thyristors (7).
EP88101815A 1987-02-20 1988-02-08 X-ray diagnostic apparatus Withdrawn EP0279317A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3705545 1987-02-20
DE3705545 1987-02-20

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EP0279317A1 true EP0279317A1 (en) 1988-08-24

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EP88101815A Withdrawn EP0279317A1 (en) 1987-02-20 1988-02-08 X-ray diagnostic apparatus

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JP (1) JPS63137500U (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5241260A (en) * 1989-12-07 1993-08-31 Electromed International High voltage power supply and regulator circuit for an X-ray tube with transient voltage protection
WO2003103346A1 (en) * 2002-05-31 2003-12-11 Philips Intellectual Property & Standards Gmbh X-ray tube
WO2010109027A1 (en) * 2009-03-25 2010-09-30 Sociedad Española De Electromedicina Y Calidad, S.A. Discharge module for x-ray-tube high-voltage cables

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE728426C (en) * 1940-12-28 1942-11-26 Siemens Reiniger Werke Ag Device for discharging the condenser of a condenser oxygen apparatus when regulating the input voltage back
DE1078244B (en) * 1958-04-18 1960-03-24 Siemens Reiniger Werke Ag X-ray diagnostic apparatus with initial loading
DE1119417B (en) * 1960-08-17 1961-12-14 Siemens Reiniger Werke Ag Circuit arrangement for extinguishing gas or vapor discharge paths connected in direct current circuits, in particular for short-term switching of X-ray tubes
DE1167457B (en) * 1963-01-10 1964-04-09 Siemens Reiniger Werke Ag X-ray diagnostic apparatus with a controllable valve arranged in the high-voltage circuit
JPS55151794A (en) * 1979-05-17 1980-11-26 Toshiba Corp X-ray apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE728426C (en) * 1940-12-28 1942-11-26 Siemens Reiniger Werke Ag Device for discharging the condenser of a condenser oxygen apparatus when regulating the input voltage back
DE1078244B (en) * 1958-04-18 1960-03-24 Siemens Reiniger Werke Ag X-ray diagnostic apparatus with initial loading
DE1119417B (en) * 1960-08-17 1961-12-14 Siemens Reiniger Werke Ag Circuit arrangement for extinguishing gas or vapor discharge paths connected in direct current circuits, in particular for short-term switching of X-ray tubes
DE1167457B (en) * 1963-01-10 1964-04-09 Siemens Reiniger Werke Ag X-ray diagnostic apparatus with a controllable valve arranged in the high-voltage circuit
JPS55151794A (en) * 1979-05-17 1980-11-26 Toshiba Corp X-ray apparatus

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5241260A (en) * 1989-12-07 1993-08-31 Electromed International High voltage power supply and regulator circuit for an X-ray tube with transient voltage protection
WO2003103346A1 (en) * 2002-05-31 2003-12-11 Philips Intellectual Property & Standards Gmbh X-ray tube
US7123688B2 (en) 2002-05-31 2006-10-17 Koninklijke Philips Electronics, N.V. X-ray tube
WO2010109027A1 (en) * 2009-03-25 2010-09-30 Sociedad Española De Electromedicina Y Calidad, S.A. Discharge module for x-ray-tube high-voltage cables
CN102484936A (en) * 2009-03-25 2012-05-30 西班牙电子医药质量公司 Discharge module for x-ray-tube high-voltage cables
US8781074B2 (en) 2009-03-25 2014-07-15 Sociedad Espanola De Electromedicina Y Calidad S.A. Discharge module for high voltage x-ray tubes
CN102484936B (en) * 2009-03-25 2015-03-18 西班牙电子医药质量公司 Discharge module for high-voltage x-ray-tube

Also Published As

Publication number Publication date
JPS63137500U (en) 1988-09-09

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