Using detectability index to determine x-ray tube current

Patent metadata

Field	Value
Publication number	US-2016296196-A1
Application number	US-201514680867-A
Country	US
Kind code	A1
Filing date	Apr 7, 2015
Priority date	Apr 7, 2015
Publication date	Oct 13, 2016
Grant date	—

Abstract

A computed tomography (CT) image apparatus includes an X-ray source to emit X-rays; and processing circuitry configured to receive a desired detectability index set by a user, the desired detectability index determining for a desired image quality of a CT scan of an object; determine an X-ray tube current that will result in the desired detectability index set by the user; and cause the X-ray source to perform a scan of the object using the determined tube current.

First claim

1 . A computed tomography (CT) apparatus, comprising:
an X-ray source to emit X-rays; and processing circuitry configured to
receive a desired detectability index set by a user, the desired detectability index determining a desired image quality of a CT scan of an object;
determine an X-ray tube current that will result in the desired detectability index set by the user; and
cause the X-ray source to perform a scan of the object using the determined tube current.

2 . The apparatus of claim 1 , wherein the processing circuitry is further configured to determine the X-ray tube current using a look-up table, wherein the look-up table includes a plurality of X-ray tube currents and a plurality of corresponding detectability indices.

3 . The apparatus of claim 1 , wherein the processing circuitry is further configured to determine the X-ray tube current to obtain the set detectability index using a simulation method.

4 . The apparatus of claim 1 , wherein the processing circuitry is further configured to determine the X-ray tube current by calculating a plurality of detectability indices for a corresponding plurality of tube currents, wherein each calculated detectability index is proportional to a module transfer function and an object function, and is inversely proportional to a noise power spectrum.

5 . The apparatus of claim 4 , wherein the processing circuitry is further configured to calculate the module transfer function using a look-up table, based on dimensions of the object, an input tube current, a contrast value, and scanning and reconstruction parameters.

6 . The apparatus of claim 4 , wherein the processing circuitry is further configured to calculate the module transfer function by reconstructing model simulation data based on dimensions of the object to generate a reconstructed image, and determining the module transfer function from the reconstructed image.

7 . The apparatus of claim 4 , wherein the processing circuitry is further configured to calculate the object function by determining a diameter and a contrast value from an image of the object.

8 . The apparatus of claim 4 , wherein the processing circuitry is further configured to calculate the noise power spectrum using a look-up table based on dimensions of the object and a contrast value of the object.

9 . A computed tomography (CT) imaging method for a CT apparatus that includes an X-ray source configured to emit X-rays, comprising:
receiving a desired detectability index set by a user for a desired image quality of a CT scan of an object; determining an X-ray tube current that will result in the desired detectability index set by the user; and causing the X-ray source to perform a scan of the object using the determined tube current.

10 . The method of claim 9 , wherein the determining step further comprises determining the X-ray tube current using a look-up table, wherein the look-up table includes a plurality of X-ray tube currents and a plurality of corresponding detectability indices.

11 . The method of claim 9 , wherein the determining step further comprises determining the X-ray tube current using a simulation method.

12 . The method of claim 9 , wherein the determining step further comprises calculating a plurality of detectability indices for a corresponding plurality of tube currents, wherein each calculated detectability index is proportional to a module transfer function and an object function, and is inversely proportional to a noise power spectrum.

13 . The method of claim 12 , wherein the determining step further comprises calculating the module transfer function using a look-up table, based on dimensions of the object, an input tube current, a contrast value, and scanning and reconstruction parameters.

14 . The method of claim 12 , wherein the determining step further comprises calculating the module transfer function by reconstructing model simulation data based on dimensions of the object to generate a reconstructed image, and determining the module transfer function from the reconstructed image.

15 . The method of claim 12 , wherein the determining step further comprises calculating the object function by determining a diameter and a contrast value from an image of the object.

16 . The method of claim 12 , wherein the determining step further comprises calculating the noise power spectrum using a look-up table based on dimensions of the object and a contrast value of the object.

17 . A non-transitory computer-readable medium storing executable instructions, which, when executed by processing circuitry of a CT apparatus that includes an X-ray source configured to emit X-rays, cause the processing circuitry to execute a method comprising:
receiving a desired detectability index set by a user for a desired image quality of a CT scan of an object; determining an X-ray tube current that will result in the desired detectability index set by the user; and causing the X-ray source to perform a scan of the object using the determined tube current.

Assignees

• Toshiba Kk
• Toshiba Medical Sys Corp

Inventors

• Boedeker Kirsten
• Nakanishi Satoru

Classifications

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• A61B6/544 Primary

  dependent on patient size · CPC title

• A61B6/5205

  involving processing of raw data to produce diagnostic data · CPC title

• A61B6/545

  involving automatic set-up of acquisition parameters · CPC title

• A61B6/582

  Calibration · CPC title