CT imaging system and method using a task-based image quality metric to achieve a desired image quality

Patent metadata

Field	Value
Publication number	US-10973489-B2
Application number	US-201816020385-A
Country	US
Kind code	B2
Filing date	Jun 27, 2018
Priority date	Sep 29, 2017
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

Computed tomography (CT) imaging system has at least one processing unit configured to receive operator inputs that include a modified system feature and a clinical task having a task object and also receive operator inputs for determining a task-based image quality (IQ) metric. The task-based IQ metric represents a desired overall image quality of image data for performing the clinical task. The image data acquired using a reference system feature. The at least one processing unit is also configured to determine an exposure-control parameter based on the task object, the modified system feature, and the task-based IQ metric. The at least one processing unit is also configured to direct the x-ray source to generate the x-ray beam during the CT scan, wherein at least one of the tube current or the tube potential during the CT scan is a function of the exposure-control parameter.

First claim

What is claimed is:

1. A computed tomography (CT) imaging system comprising:
an x-ray source configured to operate at a tube current and at a tube potential while generating an x-ray beam;
a CT detector configured to collect projection data of a person; and
at least one processing unit configured to execute programmed instructions stored in memory, the at least one processing unit, when executing the programmed instructions, configured to:
receive operator inputs that include a modified system feature and a clinical task having a task object;
determine a task-based image quality (IQ) metric based on the operator inputs, the task-based IQ metric representing a desired overall image quality of image data for performing the clinical task, the image data being acquired using a reference system feature, wherein the reference system feature and the modified system feature are a same type of feature and include a reconstruction algorithm or a scan parameter;
determine an exposure-control parameter based on the task object, the modified system feature, and the task-based IQ metric; and
direct the x-ray source to generate the x-ray beam during a CT scan, wherein at least one of the tube current or the tube potential during the CT scan is a function of the exposure-control parameter.

2. The CT imaging system of claim 1 , wherein the at least one processing unit is further configured to receive the exposure-control parameter and direct the x-ray source to generate the x-ray beam based on the exposure-control parameter.

3. The CT imaging system of claim 2 , wherein the at least one processing unit is further configured to determine a tube-current modulation (TCM) profile using the exposure-control parameter, the TCM profile specifying tube currents during the CT scan for different angular and longitudinal positions of the x-ray source, wherein directing the x-ray source to generate the x-ray beam includes directing the x-ray source to generate the x-ray beam according to the TCM profile.

4. The CT imaging system of claim 1 , wherein, for determining the exposure-control parameter, the at least one processing unit is further configured to:
determine at least one weighting factor, the at least one weighting factor being based on the task object and the reconstruction algorithm; and
calculate the exposure-control parameter using the at least one weighting factor and the task-based IQ metric.

5. The CT imaging system of claim 1 , wherein the at least one processing unit is configured to direct the x-ray source to generate the x-ray beam, wherein the exposure-control parameter has a designated relationship with respect to at least one of an image noise or a radiation dose parameter, the at least one processing unit further configured to convert the exposure-control parameter to a different exposure-control parameter.

6. The CT imaging system of claim 1 , wherein the at least one processing unit is configured to determine the task-based IQ metric using a detectability index, the detectability index being a task-based, frequency-dependent signal-to-noise ratio (SNR) metric that combines a spatial resolution and noise properties of the CT imaging system and a spatial-frequency content of the task object.

7. The CT imaging system of claim 1 , wherein the operator inputs include a target IQ reference, the target IQ reference including at least one of a noise standard deviation or a reference tube-current product.

8. The CT imaging system of claim 1 , wherein the operator inputs include a reference image having a desired overall image quality, the at least one processing unit, when executing the programmed instructions, configured to determine the task-based IQ metric using the reference image.

9. The CT imaging system of claim 8 , wherein the task-based IQ metric is based on a modulation transfer function (MTF) of the CT imaging system for the clinical task, a noise power spectrum (NPS) of the CT imaging system, and a frequency content (W) of the CT imaging system for the clinical task.

10. A method comprising:
receiving operator inputs that include a modified system feature and a clinical task having a task object;
determining a task-based image quality (IQ) metric based on the operator inputs, the task-based IQ metric representing a desired overall image quality of image data for performing the clinical task, the image data being acquired using a reference system feature, wherein the reference system feature and the modified system feature are a same type of feature and include a reconstruction algorithm or a scan parameter;
determining an exposure-control parameter based on the task object, the modified system feature, and the task-based IQ metric; and
directing an x-ray source to generate an x-ray beam during a CT scan, wherein at least one of a tube current or a tube potential during the CT scan is a function of the exposure-control parameter.

11. The method of claim 10 , wherein determining the exposure-control parameter includes:
determining at least one weighting factor, the at least one weighting factor being based on the task object and the reconstruction algorithm;
calculating the exposure-control parameter using the at least one weighting factor and the task-based IQ metric.

12. The method of claim 10 , wherein the operator inputs include at least one of a numerical value or a reference image having a desired overall image quality, wherein the exposure-control parameter is based on the task-based IQ metric, a modulation transfer function (MTF) of a CT imaging system for the clinical task, a noise power spectrum (NPS) of the CT imaging system, and a frequency content (W) of the CT imaging system for the clinical task.

13. The method of claim 10 , wherein the task-based IQ metric is obtained by a first CT imaging system, the reference system feature being used by the first CT imaging system, wherein the modified system feature is configured to be used by a second CT imaging system, wherein determining the exposure-control parameter includes determining the exposure-control parameter for the second CT imaging system.

14. A computed tomography (CT) imaging system comprising:
an x-ray source configured to operate at a tube current and at a tube potential while generating an x-ray beam;
a CT detector configured to collect projection data of a person;
at least one processing unit configured to execute programmed instructions stored in memory, the at least one processing unit, when executing the programmed instructions, configured to:
receive operator inputs that include a clinical task having a task object, a reference system feature, a modified system feature, and a target image quality (IQ) reference, the target IQ reference representing an acceptable image quality obtainable using the reference system feature, wherein the reference system feature and the modified system feature are a same type of feature and include a reconstruction algorithm or a scan parameter;
determine a task-based IQ metric based on the task object, the reference system feature, and the target IQ reference;
determine an adjusted IQ reference based on the task-based IQ metric, the task object, and the modified system feature; and
direct the x-ray source to generate the x-ray beam during a CT scan, wherein at least one of the tube current or the tube potential during the CT scan is a function of the adjusted IQ reference.

15. The CT imaging system of claim 14 , wherein the at least one processing unit is further configured to receive the adjusted IQ reference and direct the x-ray source to generate the x-ray beam based on the adjusted IQ refe

Assignees

• Gen Electric

Inventors

• Rupcich Franco
• Crotty Dominic
• Fan Jiahua
• Khobragade Parag
• Schmidt Tal Gilat

Classifications

• A61B6/4429

  related to the mounting of source units and detector units · CPC title

• A61B6/54

  Control of apparatus or devices for radiation diagnosis · CPC title

• H05G1/08

  Electrical details · CPC title

• A61B6/488

  involving pre-scan acquisition · CPC title

• A61B6/5258

  involving detection or reduction of artifacts or noise · CPC title