X-ray CT apparatus

Patent metadata

Field	Value
Publication number	US-9918693-B2
Application number	US-201514701741-A
Country	US
Kind code	B2
Filing date	May 1, 2015
Priority date	May 12, 2014
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

According to one embodiment, an X-ray CT apparatus includes a rotating body configured to house an X-ray tube which irradiates X-rays on an object; at least one weight configured to be housed in the rotating body and to adjust balance of the rotating body; a sensor configured to detect fluctuation amount in a front-back direction approximately orthogonal to a rotating surface of the rotating body; processing circuitry configured to determine moving amount of the weight based on the fluctuation amount in a front-back direction detected by the sensor; and at least one weight moving mechanism configured to be housed in the rotating body and to move a position of the weight based on the moving amount determined by the determination unit.

First claim

What is claimed is:

1. An X-ray CT apparatus, comprising:
a rotating body configured to house an X-ray tube which irradiates X-rays on an object;
at least one weight configured to be housed in the rotating body and to adjust balance of the rotating body;
a sensor configured to detect a fluctuation amount in a front-back direction approximately parallel to a rotating axis of the rotating body;
processing circuitry configured to determine a moving amount of the weight based on the fluctuation amount in the front-back direction detected by the sensor;
at least one weight moving mechanism configured to be housed in the rotating body and to move a position of the weight based on the moving amount determined by the processing circuitry; and
a memory storing a look-up table in which the fluctuation amount and the moving amount of the weight necessary for reducing the fluctuation amount are associated with each other,
wherein the processing circuitry is further configured to determine the moving amount of the weight by referring to the look-up table.

2. The X-ray CT apparatus according to claim 1 ,
wherein the sensor is configured to detect a tilt angle of the rotating body; and
the processing circuitry is configured to determine the moving amount of the weight using the fluctuation amount in the front-back direction based on the fluctuation amount of the tilt angle detected by the sensor.

3. The X-ray CT apparatus according to claim 2 ,
wherein the sensor includes a tilt angle encoder configured to detect the tilt angle of the rotating body and is further configured to detect the tilt angle of the rotating body based on output from the tilt angle encoder.

4. The X-ray CT apparatus according to claim 1 ,
wherein the sensor includes an optical sensor configured to irradiate light onto the rotating surface and is further configured to detect the fluctuation amount in the front-back direction by using the optical sensor.

5. The X-ray CT apparatus according to claim 1 , further comprising a fixed body configured to be disposed on a rear side of the rotating body and to rotatably support the rotating body,
wherein the sensor includes a pressure sensor disposed to be in contact with the fixed body and is further configured to detect the fluctuation amount in the front-back direction by using the pressure sensor.

6. The X-ray CT apparatus according to claim 1 , further comprising a motor configured to rotate the rotating body,
wherein the processing circuitry is further configured to determine a torque fluctuation amount based on a fluctuation amount of a drive current of the motor, determine a fluctuation amount in a rotating surface of the rotating body based on the torque fluctuation amount, and further determine the moving amount of the weight in the rotating surface based on the fluctuation amount in the rotating surface.

7. The X-ray CT apparatus according to claim 1 ,
wherein the weight moving mechanism includes an adjusting motor and a motion convertor that converts rotational motion of the adjusting motor into linear motion.

8. The X-ray CT apparatus according to claim 7 ,
wherein the motion convertor includes a ball screw and a slider meshing with the ball screw; and
the weight is connected to the slider.

9. The X-ray CT apparatus according to claim 8 , further comprising a worm gear having a self-locking function,
wherein a worm wheel of the worm gear is connected to the ball screw and a worm of the worm gear is connected to a rotary shaft of the adjusting motor.

10. The X-ray CT apparatus according to claim 6 , further comprising a plurality of components housed in the rotating body for obtaining the X-ray projection data, wherein at least one of the plurality of components serves as the weight;
wherein the weight moving mechanism is further configured to move the at least one of the plurality of components in a predetermined radial direction in the rotating surface of the rotating body and to move the at least one of the plurality of components in the front-back direction orthogonal to the rotating surface.

11. The X-ray CT apparatus according to claim 6 , further comprising a first weight, a second weight, a first weight moving mechanism, and a second weight moving mechanism,
wherein the first weight moving mechanism is configured to move the first weight in a predetermined racial direction in the rotating surface, and the second weight moving mechanism is configured to move the second weight in the front-back direction orthogonal to the rotating surface.

Assignees

• Toshiba Medical Sys Corp

Inventors

• Gotanda Katsumi

Classifications

• G01M1/36

  by adjusting position of masses built-in the body to be tested · CPC title

• A61B6/54 Primary

  Control of apparatus or devices for radiation diagnosis · CPC title

• A61B6/035

  Mechanical aspects of CT · CPC title

• A61B6/447

  the source unit or the detector unit being mounted to counterpoise or springs · CPC title