Correcting an imbalance on the basis of the acquired radiation data

Patent metadata

Field	Value
Publication number	US-11255801-B2
Application number	US-202016814268-A
Country	US
Kind code	B2
Filing date	Mar 10, 2020
Priority date	Mar 19, 2019
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

A method is for correcting an imbalance in a computed tomography system, in which a supporting structure includes a radiation source is fitted on a fixed mounting frame. The supporting structure rotates together with the radiation source about a measurement space, in which is fixed in place a measurement object having a known attenuation response for the radiation emitted by the radiation source. The method includes detecting first measurement data of the radiation while the supporting structure rotates about the measurement object, determining an imbalance arising during the rotation of the supporting structure on the basis of the acquired first measurement data of the radiation, and determining a position and a weight of at least one counterweight on the supporting structure in order to reduce the determined imbalance, or determining correction data, which is used to correct the imbalance in software.

First claim

What is claimed is:

1. A method for correcting an imbalance in a computed tomography system, in which a support including a radiation source is fitted on a fixed mounting frame, the support being configured to rotate together with the radiation source about a measurement space in which is fixed in place a measurement object having a known attenuation response for radiation emitted by the radiation source, the method comprising:
detecting first measurement data of the radiation while the support rotates about the measurement object;
determining whether or not an imbalance arises during rotation of the support based upon the first measurement data of the radiation detected;
determining correction data, upon the determining indicating that an imbalance arises, based upon the imbalance determined; and
calculating corrected measurement data of the radiation by applying the correction data determined to further measurement data, the corrected measurement data calculated being usable to reduce impact of the imbalance compared with the first measurement data, wherein the detecting of first measurement data of the radiation includes acquiring a plurality of first measurement data at different rotational speeds of the support, wherein the calculating of corrected measurement data includes calculating respective correction data for each of the different rotational speeds, wherein a further rotational speed is determined at which the further measurement data is acquired, and wherein the correction data associated with the further rotational speed is determined by interpolation from the respective correction data for each of the different rotational speeds and is applied to the further measurement data to calculate the corrected measurement data.

2. The method of claim 1 , wherein a check is made to ascertain whether the imbalance determined is relatively greater than a limit value, and upon ascertaining that the imbalance determined is relatively greater than the limit value, the method further comprises calculating a position and a weight of at least one counterweight on the support.

3. The method of claim 1 , wherein emitted radiation is detected by a detector having a plurality of detectors in an array arrangement, the method further comprising:
determining which detectors, of the plurality of detectors, detect the radiation of the first measurement data as a function of angular position of the radiation source;
determining as a function of the angular position of the radiation source, in which detectors, of the plurality of detectors, the radiation of the first measurement data should have been detected assuming no imbalance existed;
determining correction information for the plurality of detectors, of the plurality of detectors, specifying a detector that should have detected radiation, that is detected in an actual detector; and
determining the correction data from the correction information determined.

4. The method of claim 1 , further comprising:
reducing impact of the imbalance compared with the first measurement data using the correction data calculated.

5. The method of claim 1 , further comprising:
detecting second measurement data of the radiation, while the radiation source is positioned in a fixed angular position with respect to the mounting frame and is not rotating about the measurement space; and
using the first measurement data of the radiation and the second measurement data of the radiation detected, to determine the imbalance.

6. The method of claim 5 , further comprising:
determining a difference in a position of the first measurement data, on a detector for the radiation from a position of the second measurement data, on the detector, the difference being used to determine the imbalance.

7. A non-transitory computer program product storing program segments, directly loadable into a memory of a programmable controller of a computed tomography system, to perform the method of claim 1 when the program segments are executed by the programmable controller.

8. A non-transitory electronically readable data storage medium storing electronically readable control information, designed to perform the method of claim 1 when the electronically readable control information is executed by a controller of a computed tomography system.

9. A computed tomography system, comprising:
a mounting frame, fixed in position;
a support, rotatably connected to the mounting frame, configured to rotate about a measurement space together with a radiation source fitted on the support, a measurement object, having a known attenuation response for the radiation emitted by the radiation source, being fixed in place in the measurement space;
a detector, designed to detect the radiation; and
a controller, designed to:
detect first measurement data of the radiation while the support rotates about the measurement object,
determine whether or not an imbalance during rotation of the support, based upon the first measurement data of the radiation detected,
determine, upon determining an imbalance being has arisen, correction data based upon the imbalance determined, and

calculate corrected measurement data of the radiation by applying the correction data determined to the further measurement data, the corrected measurement data calculated being usable to reduce impact of the imbalance compared with the first measurement data, wherein the controller is further configured to acquire a plurality of the first measurement data at different rotational speeds of the support, and wherein the controller is further configured to calculate respective correction data for each of the different rotational speeds, and wherein the controller is further configured to determine a further rotational speed at which the further measurement data is acquired, and wherein the correction data associated with the further rotational speed is determined by interpolation via the controller from the respective correction data for each of the different rotational speeds and is applied to the further measurement data to calculate the corrected measurement data.

10. The computed tomography system of claim 9 , wherein the controller is further designed to reduce the impact of the imbalance compared with the first measurement data using the correction data calculated and without using counterweights.

Assignees

• Siemens Healthcare Gmbh

Inventors

• Mueller Hans-Juergen
• Grasruck Michael
• Berner Matthias
• Kiessling Florian

Classifications

• G01M1/36

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

• A61B6/4078

  Fan-beams · CPC title

• A61B6/4208

  characterised by using a particular type of detector · CPC title

• G01N23/046 Primary

  using tomography, e.g. computed tomography [CT] · CPC title

• G01M1/28

  with special adaptations for determining imbalance of the body in situ, e.g. of vehicle wheels · CPC title