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AN ELECTRON GUN-TYPE X-RAY TUBE FOR VOLUME COMPUTED TOMOGRAPHY

IP.com Disclosure Number: IPCOM000033816D
Publication Date: 2004-Dec-29
Document File: 6 page(s) / 35K

Publishing Venue

The IP.com Prior Art Database

Abstract

In an embodiment, an electron gun-type X-ray tube is provided. The X-ray tube includes a grid-type electron gun and a target, wherein the electron gun is configured to periodically shut off electrons from being directed towards the target during a scan. In another embodiment, a target structure for an electron gun-type X-ray tube is provided. The structure includes a plurality of target surfaces separated by a predetermined distance along a predetermined direction.

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AN ELECTRON GUN-TYPE X-RAY TUBE FOR VOLUME COMPUTED TOMOGRAPHY

FIELD OF THE INVENTION

[0001]   This invention relates generally, to electron gun-type X-ray tubes, and more particularly, to deflecting electron type X-ray tubes, especially for Computed Tomography (CT) procedures.

BACKGROUND OF THE INVENTION

 

[0002]   Projection aliasing has been a major problem in CT Scanners, especially, in third generation CT design in which no additional samples can be rendered within the width of a detector cell.  Aliasing artifact may occur particularly, based on the Nyquist sampling criteria. 

[0003]   To overcome the problems of aliasing artifact, X-ray focal spot wobble scan technique has been of great use.  However, in this wobble scan mode, the X-ray spot stays in the first location during the first data acquisition.  When the detector rotates to a slightly different angle and the new detector cell positions straddle the previously cell positions, the X-ray focal spot is deflected, either electro-statically or electro-magnetically, to the first location.  Although this technique effectively achieves a double sampling of the projection signal, as the sampling rate increases, the defection-to-dwell ratio increases since it takes a finite amount of time for the field to change, and hence the effectiveness of the focal spot wobble becomes low. 

SUMMARY OF THE INVENTION

[0004]    In an embodiment, an electron gun-type X-ray tube is provided. The X-ray tube includes a grid-type electron gun and a target, wherein the electron gun is configured to periodically shut off electrons from being directed towards the target during a scan. 

[0005]    In another embodiment, a target structure for an electron gun-type X-ray tube is provided.  The structure includes a plurality of target surfaces separated by a predetermined distance along a predetermined direction.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]    FIG. 1 shows an elevation of the X-ray tube according to one embodiment of the present invention.

[0007]    FIG. 2 shows an example of the deflection-timing diagram for the X-ray beam according to one embodiment of the present invention.

[0008]    FIG. 3 shows an example of the target structure according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0009]    Various embodiments of this invention describe an electron gun-type X-ray tube.  Further embodiments of this invention provide a target structure for an electron gun type X-ray tube.

[0010]    In general, X-ray tube 10 according to one embodiment of this invention (see FIG. 1) includes a grid type electron gun 14, a deflection coil 12 and a target 16, wherein the electron gun 14 is configured to shut the electrons from being directed towards the target 16 during a scan. 

[0011]    In an embodi...