EP0682466B1 - Röntgenanlage - Google Patents

Röntgenanlage Download PDF

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Publication number
EP0682466B1
EP0682466B1 EP95201189A EP95201189A EP0682466B1 EP 0682466 B1 EP0682466 B1 EP 0682466B1 EP 95201189 A EP95201189 A EP 95201189A EP 95201189 A EP95201189 A EP 95201189A EP 0682466 B1 EP0682466 B1 EP 0682466B1
Authority
EP
European Patent Office
Prior art keywords
tube
current
ray
value
time
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.)
Expired - Lifetime
Application number
EP95201189A
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German (de)
English (en)
French (fr)
Other versions
EP0682466A1 (de
Inventor
Peter C/O Philips Patentverwaltung Gmbh Stege
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.)
Philips Intellectual Property and Standards GmbH
Koninklijke Philips NV
Original Assignee
Philips Patentverwaltung GmbH
Koninklijke Philips Electronics NV
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.)
Filing date
Publication date
Application filed by Philips Patentverwaltung GmbH, Koninklijke Philips Electronics NV filed Critical Philips Patentverwaltung GmbH
Publication of EP0682466A1 publication Critical patent/EP0682466A1/de
Application granted granted Critical
Publication of EP0682466B1 publication Critical patent/EP0682466B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H05G1/30—Controlling
    • H05G1/34—Anode current, heater current or heater voltage of X-ray tube

Definitions

  • the invention relates to an x-ray system with an x-ray tube and an x-ray generator for operating the X-ray tube, which is heated by a heating current Contains cathode, with effective in a recording mode Means for raising the heating current to a boost value with the tube voltage switched off during a boost time and with means also effective in the recording mode Reduction of the heating current to a value suitable for the subsequent X-ray exposure and to switch on the tube voltage.
  • Such a system is e.g. known from EP-A-0 025 688.
  • the cathode - with the tube voltage switched off - to supply a heating current that is significantly greater than the heating current for the subsequent X-ray (with the tube voltage switched on) is necessary.
  • the boost time depends on the tube current, which in the following Recording should flow. The greater this tube current the longer the boost time.
  • the X-ray generator for Boost times required for a specific tube type store it and store it on an x-ray to call.
  • This boost time table contained in the memory is manufactured by the X-ray tube manufacturer in one complicated measurement procedure determined, for everyone X-ray tube type separately.
  • the given boost times are typical values, i.e. it can happen that the cathode temperature is higher at the end of the boost time or is lower than that for the respective tube current required temperature. Therefore, after the boost time the heating current is reduced to the value that it at X-ray should have. Then if after another Time interval of 200 to 300 ms the tube voltage is switched on the cathode temperature is stationary Value reached that required for the recording Value corresponds.
  • the object of the present invention is an x-ray system to create, in which the preparation time, i.e. the period until an X-ray begins can be further shortened.
  • This task is carried out on the basis of an X-ray system type mentioned solved in that the X-ray generator is designed for a special mode in which switched on tube voltage the heating current to the Boost value is raised that means for measuring the im Special mode flowing tube current are provided that Means for storing the time course of the measured Tube current or a value derived therefrom are provided and that means for deriving the boost time from the time history stored in the memory are provided.
  • the boost times in a special mode of the X-ray generator can be determined, in which the tube voltage is switched on and the heating current is raised to its boost value. Grows in this mode the tube current continuously up to a maximum value after which the tube voltage is switched off and the heating current is lowered or also switched off. Which the time course resulting until the device is switched off is measured and saved. If on a subsequent X-ray, which is carried out in the recording mode certain tube current is specified, one can from the stored history over time how long it - with heating current increased to the boost value - takes until the cathode temperature has reached a value at which just the desired tube current is being emitted. This Period corresponds to the period within which stored tube current curve the relevant tube current value is reached; it is in record mode as Boost time specified.
  • the invention allows the exact in a simple manner Determination of the required boost times, individually for the respective x-ray tube. So that is Boost time just as big as it needs to be, so in the end the boost time exactly for the emission of the desired Tube current required temperature is reached. That's why it is no longer necessary to set the boost time to follow the second interval in which the heating current to the value required for the respective tube current is lowered. This shortens the preparation time considerably. It is also advantageous that the Special operating mode with the X-ray generator in larger time intervals can be repeated. Thereby signs of aging are taken into account that a Influence on the characteristics of the respective X-ray tube to have. When changing the X-ray tube, there is no change of the boost time memory required, and it can too X-ray tubes are used, their temperature behavior is unknown.
  • the tube current doesn't just depend on that Heating current, but also from that on the x-ray tube applied tube voltage.
  • Boost time belonging to tube current and tube voltage There are a number of ways how to make that to a certain combination Boost time belonging to tube current and tube voltage can determine.
  • One possibility would be to temporal course of the tube current in the special operating mode repeat for a variety of tube voltages, so that there would be a bevy of curves that the temporal course of the tube current with the tube voltage would represent as parameters. If then in normal operating mode specified a certain tube voltage would have to be in the same operating mode for the same tube voltage measured time course of the tube current used to determine the tube voltage will. This would be relatively expensive because in the special operating mode a variety of temporal tube currents should be measured and stored.
  • the time course of the tube current only to be recorded with a single tube voltage, if provided according to a preferred development of the invention is that a second memory is provided in that for different tube voltages and tube currents stationary heating current values are stored and that the Means for deriving the boost time on the first memory and access the second memory.
  • the X-ray generator shown schematically in FIG. 1 for feeding an X-ray tube 1 comprises a first one High voltage generator 2 for generating a positive High voltage for the anode of the x-ray tube and one second high voltage generator 3 for generating a negative high voltage for the cathode of the x-ray tube.
  • the two high voltage generators 2 and 3 are over one Resistor 4 connected in series, one end of which is grounded is.
  • the resistor 4 is used to measure the Anode of the X-ray tube 1 flowing tube current.
  • the high-voltage generators 2 and 3, ie the time profile of the tube voltage U generated by them, can be controlled by a control unit 5, which can contain a suitably programmed microprocessor.
  • the voltage drop across the resistor 4, ie a value proportional to the tube current, is fed to the control unit via an analog-digital converter 6.
  • the control unit also specifies the heating current for the cathode of the X-ray tube 1, which is generated by a heating current control circuit 7.
  • the control unit works with a first memory 8, in which dynamic data are stored, and with a second memory 9, in which static or stationary data are stored, and links them in a manner yet to be explained with the values of for an X-ray exposure Tube current I r and tube voltage U.
  • the heating current I h is raised to a boost value.
  • This boost value is usually much larger than the tube current flowing during an X-ray exposure, and it preferably corresponds to the maximum permissible value - for example 11 A.
  • the tube voltage U is switched on for the X-ray exposure.
  • the heating current is reduced to a value between 3 A and 7 A, ie to a value which is greater than the quiescent current and less than the boost value.
  • a stationary characteristic field is shown, which for different voltages U 1 . . . U 4 indicates the tube current I r , which occurs at a certain static or stationary heating current. From this diagram it can easily be seen which heating current I h has to be set in the stationary case for a specific combination of tube current I r and tube voltage U. This family of curves, ie the heating current as a function of the tube current or the tube voltage, is stored in the second memory 9. How to determine such a characteristic field individually for the respective X-ray tube is described in DE-PS 27 03 420, among others.
  • Fig. 2 part B, shows the time course of heating current I h and tube current U during the special mode.
  • the time profile of the tube current is measured and digitized during the special mode by digitizing the voltage across the resistor 4 by the analog-digital converter 6, so that a measurement value of the tube current is provided for measuring time intervals of, for example, 3 ms Available. The course measured in this way is stored in the first memory 8.
  • the flow chart according to FIG. 4 explains the time sequence of the steps carried out by the control unit during the special mode.
  • the heating current is set to a quiescent current value or a standby value I stb .
  • the voltage on the tube is switched off.
  • a tube current then begins to flow, as shown in FIG. 3b.
  • the tube current is measured, digitized every 3 ms and stored in the first memory 8 (block 52).
  • the heating current is then reduced again to the quiescent current I stb and the tube voltage is switched off (block 54).
  • the following sequence then results for an x-ray exposure:
  • the values of tube current and tube voltage desired for the x-ray exposure are specified (block 55).
  • the stationary heating current required for the X-ray exposure is determined from these values, with the aid of the values stored in the memory 9 (block 56).
  • the boost time t B associated with this heating current value is then determined from curve I cor in FIG. 3, part B, or in memory 8.
  • the heating current is then raised to the boost value during the time period t B , with no voltage being applied to the X-ray tube (block 57).
  • the heating current is reduced to the value determined in block 56 and the desired tube voltage U is switched on (block 58).
  • the desired tube current I r then flows.
  • an X-ray exposure is preceded by fluoroscopy, in which the tube current I r has a small but no longer negligible value. If the filament were then heated in the recording mode during the full boost time determined in the manner described above, the temperature would be somewhat too high. This can be prevented by reducing this boost time by the value of that boost time which is assigned to the heating current I h flowing in the fluoroscopic mode.

Landscapes

  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • X-Ray Techniques (AREA)
EP95201189A 1994-05-11 1995-05-09 Röntgenanlage Expired - Lifetime EP0682466B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4416556 1994-05-11
DE4416556A DE4416556A1 (de) 1994-05-11 1994-05-11 Röntgengenerator

Publications (2)

Publication Number Publication Date
EP0682466A1 EP0682466A1 (de) 1995-11-15
EP0682466B1 true EP0682466B1 (de) 1998-11-11

Family

ID=6517823

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95201189A Expired - Lifetime EP0682466B1 (de) 1994-05-11 1995-05-09 Röntgenanlage

Country Status (4)

Country Link
US (1) US5546441A (ja)
EP (1) EP0682466B1 (ja)
JP (1) JP3560681B2 (ja)
DE (2) DE4416556A1 (ja)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1110436A1 (en) * 1999-07-06 2001-06-27 Koninklijke Philips Electronics N.V. X-ray examination apparatus
DE10004987A1 (de) * 2000-02-04 2001-07-19 Siemens Ag Verfahren und Vorrichtung zur Verlängerung der Lebensdauer von thermionischen Emittern
DE10038946C2 (de) * 2000-08-09 2002-03-14 Siemens Ag Heizstromkreis für eine Kathode einer Röntgenröhre und Verfahren zur Ermittlung einer Führungsgröße einer Stromregeleinrichtung eines Heizstromkreises
FR2855360B1 (fr) * 2003-05-20 2006-10-27 Ge Med Sys Global Tech Co Llc Procede d'alimentation d'un filament de chauffage d'un tube a rayons x et tube a rayons x correspondant
JP4653521B2 (ja) * 2005-03-07 2011-03-16 株式会社東芝 医療用ｘ線管装置及び医療用ｘ線管制御方法
JP5129692B2 (ja) * 2008-08-22 2013-01-30 ミカサ株式会社 Ｘ線発生装置及びｘ線管の駆動方法
WO2011024136A1 (en) * 2009-08-31 2011-03-03 Koninklijke Philips Electronics N.V. Boosting/blanking the filament current of an x-ray tube
CN105455829A (zh) * 2014-08-04 2016-04-06 锐珂（上海）医疗器材有限公司 放射性射线照相技术中控制射线管的管电流的方法及相应的系统

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2542016A1 (de) * 1975-09-20 1977-03-24 Philips Patentverwaltung Schaltungsanordnung zur einstellung des aufnahmestroms einer roentgenroehre
DE2703420C2 (de) * 1977-01-28 1985-11-21 Philips Patentverwaltung Gmbh, 2000 Hamburg Verfahren zum Einstellen des durch eine Röntgenröhre fließenden Röhrenstromes und Schaltungsanordnung zur Durchführung des Verfahrens
EP0025688A3 (en) * 1979-09-13 1981-05-27 Pfizer Inc. Process for rapidly achieving stabilized X-ray emission from an X-ray tube
DE3122185A1 (de) * 1981-06-04 1982-12-30 Philips Patentverwaltung Gmbh, 2000 Hamburg Verfahren zum betrieb eines roentgengenerators und roentgengenerator zur durchfuehrung dieses verfahrens
JPS62246300A (ja) * 1986-04-18 1987-10-27 Morita Mfg Co Ltd Ｘ線診断装置
US4775992A (en) * 1986-09-19 1988-10-04 Picker International, Inc. Closed loop x-ray tube current control
US4930146A (en) * 1989-07-10 1990-05-29 General Electric Company X-ray tube current control with constant loop gain
US5077773A (en) * 1990-07-05 1991-12-31 Picker International, Inc. Automatic filament calibration system for x-ray generators

Also Published As

Publication number Publication date
DE4416556A1 (de) 1995-11-16
DE59504188D1 (de) 1998-12-17
US5546441A (en) 1996-08-13
JP3560681B2 (ja) 2004-09-02
JPH07320893A (ja) 1995-12-08
EP0682466A1 (de) 1995-11-15

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