Methods for x-ray tube rotors with speed and/or position control

Patent metadata

Field	Value
Publication number	US-11523793-B2
Application number	US-202016869999-A
Country	US
Kind code	B2
Filing date	May 8, 2020
Priority date	May 8, 2020
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

Various methods and systems are provided for an x-ray imaging system. In one example, a method for decelerating a rotor of an x-ray tube of an imaging system includes controlling and/or monitoring a speed and position of the rotor, passing the rotor through a first position where a force exerted on the rotor, is less than Earth's gravitational pull, the force due to a combination of gravity and radial acceleration, and initiating a predefined deceleration profile to decelerate the rotor to a halt when the x-ray tube passes through the first position.

First claim

The invention claimed is:

1. A method for operating an x-ray tube, comprising:
controlling and/or monitoring a speed and position of a rotor of the x-ray tube, the speed and position of the rotor provided by configuring the x-ray tube with permanent magnets, and of a target of the x-ray tube; and
using the monitored speed and position of the target to perform operations to increase useful x-ray tube life, increase image resolution, and/or increase x-ray flux.

2. The method of claim 1 , wherein performing the operations includes correcting image data based on a correction factor estimated from an x-ray spectrum emitted from the target of the x-ray tube and wherein the target includes at least one region with imperfections.

3. The method of claim 1 , wherein performing the operations includes identifying the target as a source of a high voltage instability event when the target has a localized imperfection causing the high voltage instability event.

4. The method of claim 1 , wherein performing the operations includes determining a location of an impurity on the target and removing the impurity by applying a low x-ray tube current to the impurity.

5. The method of claim 1 , wherein performing the operations includes determining a location of cracks in the target and repairing the cracks by at least one of slow continuous heating and pulsed heating.

6. The method of claim 1 , wherein performing the operations includes configuring the target with two or more segments to vary a position of a focal track of the target along an axis perpendicular to a surface of the target and wherein varying the position of the focal track along the axis provides focal spot wobble without electron beam deflection.

7. The method of claim 1 , wherein performing the operations includes adapting the target with two or more concentric focal tracks and alternating an interaction of an electron beam with the target between the two or more concentric focal tracks to provide z-wobble.

8. The method of claim 1 , wherein performing the operations includes adapting the target with at least one groove configured to trap x-rays emitted by an electron beam striking the target and wherein the x-rays are trapped within the at least one groove when the electron beam interacts with the at least one groove during rotation of the target.

9. The method of claim 8 , further comprising adapting the target with two or more materials, the two or more materials each emitting a different x-ray spectrum upon interaction with the electron beam and wherein the electron beam alternates between striking each of the two of more materials as the target rotates.

10. A CT imaging system, comprising:
a rotating gantry;
an x-ray tube coupled to the gantry and having a rotor driving rotation of a target of the x-ray tube; and
a control unit including executable instructions stored in non-transitory memory causing the control unit to:
control and/or monitor a speed and a position of a rotor of the x-ray tube as provided by configuring the x-ray tube with permanent magnets;
control deceleration of the rotor based on the monitored speed and the monitored position; and
use the monitored speed and the monitored position of the rotor to conduct operations to enhance image quality and/or increase rotor life.

11. The CT imaging system of claim 10 , wherein the x-ray tube has liquid bearings and the permanent magnets are located in at least one of a bearing assembly and the rotor to enable monitoring of the speed and the position of the rotor in real-time.

12. The CT imaging system of claim 10 , wherein a speed and a position of the target is known based on the monitored speed and the monitored position of the rotor and wherein controlling the speed and position of the rotor adjusts the speed and position of the target relative to an electron beam striking the target.

Assignees

• Ge Prec Healthcare Llc

Inventors

• Rogers Carey
• Neculaes Vasile Bogdan
• Tapadia Nidhishri
• Cross Andrew Thomas
• Wiedmann Uwe

Classifications

• H01J35/1017

  Bearings for rotating anodes · CPC title

• H05G1/52

  Target size or shape; Direction of electron beam, e.g. in tubes with one anode and more than one cathode · CPC title

• A61B6/4014

  arranged in multiple source-detector units · CPC title

• H05G1/66 Primary

  Circuit arrangements for X-ray tubes with target movable relatively to the anode · CPC title

• H02P23/20

  Controlling the acceleration or deceleration · CPC title