Boosting/blanking the filament current of an X-ray tube

Patent metadata

Field	Value
Publication number	US-9497839-B2
Application number	US-201013384870-A
Country	US
Kind code	B2
Filing date	Aug 26, 2010
Priority date	Aug 31, 2009
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

For boosting/blanking the filament current of a cathode of an X-ray tube the temporal variation of the tube current of the X-ray tube is measured and stored in a first memory. Then an iterative boosting/blanking is performed wherein the boosting/blanking current is applied to the filament for a short time interval (Δt), based on the stored temporal variation of the tube current the tube current after the short time interval (ΔT) is determined, and the tube current is stored in a second memory. Based on the stored temporal variation of the tube current it is determined if the tube current (IE) is less than a target value (IE 2 ) thereof, and if so, the boosting/blanking current is applied to the filament for an additional time interval (Δt), else it is determined that the tube current (IE) is equal to the target value (IE 2 ). Therefore, the tube current (IE) after each time interval (Δt) is known (may be determined from the tube current data stored in the second memory)such that the iterative boosting/blanking may be interrupted anytime.

First claim

The invention claimed is:

1. A boosting/blanking method comprising the steps of:
a) measuring temporal variation of a tube current of an X-ray tube during boost;
b) storing the temporal variation in a first memory;
c) applying a boosting/blanking current to a filament of a cathode of the X-ray tube for a short time interval;
d.1) determining, based on the stored temporal variation, the tube current after the short time interval;
d.2) determining, based on the stored temporal variation, whether the tube current after the short term interval is less than a target value; and
d.3) if the tube current after the short term interval is determined to be less than said target value, returning to step c);
wherein if, instead, the tube current after the short term interval is determined not to be less than said target value, returning to step c) is not performed.

2. The method of claim 1 , wherein the time interval is short compared to a duration of time between a starting value and the target value.

3. The method of claim 1 , wherein the temporal variation of the tube current is measured with a tube voltage as a parameter, and a plurality of temporal variations are stored in the first memory.

4. The method of claim 1 , wherein, in case said applying is of a blanking current, said applying is to reduce said tube current that is to be subject to the determining of step d.1).

5. The method of claim 1 , said interval being short enough that said applying is invoked multiple times to achieve said target value.

6. An X-ray generator configured for at least one of boosting and blanking a filament current of a filament of a cathode of an operable X-ray tube, said X-ray generator comprising:
a current measuring unit configured for measuring temporal variation of tube current of an X-ray tube during boost;
a first memory configured for storing the measured temporal variation;
a filament current control unit configured for generating said filament current corresponding to at least one of boosting and blanking current that causes existing tube current to respectively rise or fall;
a second memory for storing a quantifying indication of said existing tube current after each one of a plurality of time intervals of the at least one of boosting and blanking current; and
a control unit configured for controlling the X-ray generator, the X-ray tube, and said storing in said second memory in an X-ray exposure mode, said X-ray exposure mode not being a preparatory mode in which a boost time is computed for later use in an X-ray exposure mode, said control unit being further configured for, responsive to an interruption of correspondingly said boosting or said blanking, switching targeting over to a new tube current value and using an indication from among the stored indications to adjust a re-invocation of said generating so as to achieve said value.

7. The X-ray generator of claim 6 , wherein the control unit determines said filament current.

8. An X-ray system comprising the X-ray generator and the X-ray tube of claim 6 .

9. The X-ray generator of claim 6 , said tube current of an X-ray tube being tube current of said operable X-ray tube.

10. The X-ray generator of claim 9 , wherein said control unit determines a duration of said time intervals.

11. The X-ray generator of claim 6 , wherein the time interval is short compared to a duration of time of correspondingly the boosting or blanking.

12. The X-ray generator of claim 6 , said interval being short enough that the generated current correspondingly rises or falls multiple times to achieve a target value.

13. The X-ray generator of claim 6 , said filament current control unit being further configured for iteratively applying said filament current so as to progressively increment, or decrement, tube current of said operable X-ray tube, the iterative applying comprising applying and applying again.

14. The X-ray generator of claim 6 , configured for said generating of a blanking current so as to cause said fall.

15. The X-ray generator of claim 6 , said controller being further configured for fetching, from said second memory, the indication to be used in said using.

16. The X-ray generator of claim 6 , the causing to respectively rise or fall causing corresponding rise or fall toward a targeted tube current from which the switching over is to occur.

17. A non-transitory computer readable medium embodying a computer program for at least one of boosting, and blanking, a filament current of a filament of a cathode of an operable X-ray tube, said program having instructions executable by a processor to carry out a plurality of acts, among said plurality there being the acts of:
a) measuring temporal variation of tube current of an X-ray tube during boost;
b) storing the temporal variation in a first memory, thereby creating stored temporal variation;
c) applying respectively a boosting, or blanking, current to the filament of said cathode for a short time interval;
d.1) determining, for tube current that exists after the interval for said operable X-ray tube, a quantifying indication of the existing tube current; and storing said indication in a second memory;
d.2) determining, based on said stored temporal variation, whether said existing tube current is less than a target value of said existing tube current;
d.3) if it is determined in step d.2) that said existing tube current is less than said target value, returning to step c); and
d.4) if it is, instead, determined in step d.2) that said existing tube current is not less than said target value, not returning to step c).

18. An X-ray generator configured for at least one of boosting and blanking a filament current of a filament of a cathode of an operable X-ray tube, said X-ray generator comprising:
a current measuring unit configured for measuring tube current of an X-ray tube during boost;
a first memory configured for storing temporal variation of said tube current;
a filament current control unit configured for generating said filament current corresponding to at least one of boosting and blanking current that causes existing tube current to respectively rise or fall;
a second memory for storing a quantifying indication of said existing tube current after each one of a plurality of time intervals of the at least one of boosting and blanking current; and
a control unit configured for controlling the X-ray generator, the X-ray tube, and said storing in said second memory in an X-ray exposure mode, said X-ray exposure mode not being a preparatory mode in which a boost time is computed for later use in an X-ray exposure mode, said control unit being further configured for comparing a stored indication to a targeted tube current, and for, responsive to an interruption dynamically switching targeting to a new tube current, using an indication from among the quantifying indications to shorten a reaction time in re-invoking said generating toward meeting the targeted new tube current.

19. The X-ray generator of claim 18 , said controller being further configured for fetching, from said second memory, the indication to be used in said using.

20. The X-ray generator of claim 18 , the causing to respectively rise or fall causing corresponding rise or fall toward said targeted tube current.

21. The X-ray generator of claim 18 , configured for said generating of a blanking current so as to cause said fall.

Assignees

• Striker Timothy
• Lehmann Thomas
• Koninklijke Philips Nv

Inventors

• Striker Timothy
• Lehmann Thomas

Classifications

• H05G1/34 Primary

  Anode current, heater current or heater voltage of X-ray tube · CPC title

• H05G1/46

  Combined control of different quantities, e.g. exposure time as well as voltage or current · CPC title

• H05G1/56

  Switching-on; Switching-off · CPC title

• H05G1/58

  Switching arrangements for changing-over from one mode of operation to another, e.g. from radioscopy to radiography, from radioscopy to irradiation {or from one tube voltage to another} · CPC title