Dose reduction for cardiac computed tomography

Patent metadata

Field	Value
Publication number	US-2022022836-A1
Application number	US-202117375895-A
Country	US
Kind code	A1
Filing date	Jul 14, 2021
Priority date	Jul 14, 2020
Publication date	Jan 27, 2022
Grant date	—

Abstract

Methods, devices, and systems for computed tomography (CT) imaging technologies that are tailored to specific regions of interest and provide a reduced radiation dose. An imaging system for cardiac CT comprises a beam-shaping filtration and exposure control technologies specifically tailored to imaging of the heart.

First claim

What is claimed is:

1 . A method of reducing radiation dose in computed tomography (CT) imaging, comprising:
positioning a region of interest of an imaging target proximate to an isocenter of a CT scanner; and adjusting a fluence of X-ray radiation produced by an X-ray source of the CT scanner using a beam-shaping filter, wherein the beam-shaping filter is disposed between the X-ray source of the CT scanner and the region of interest, and wherein the beam-shaping filter is configured to attenuate the X-ray radiation on areas of the imaging target located outside of the region of interest and simultaneously transmit the X-ray radiation to the areas of the imaging target located outside of the region of interest to provide a fluence of the X-ray radiation on the areas of the imaging target located outside of the region of interest at a level less than a predetermined fraction of a fluence of the X-ray radiation within the region of interest.

2 . The method of claim 1 , wherein the positioning the region of interest of the imaging target is such that the isocenter of the CT scanner is within the region of interest.

3 . The method of claim 1 , wherein the beam-shaping filter is a static filter.

4 . The method of claim 1 , wherein the beam-shaping filter is configured to attenuate the fluence of X-ray radiation produced by the X-ray source as a function of a distance from the isocenter.

5 . The method of claim 4 , wherein the beam-shaping filter is configured to provide a first degree of fluence attenuation for the distances from the isocenter within a first range of distances and provide a second degree of fluence attenuation for the distances from the isocenter outside the first range of distances, wherein the first degree of fluence attenuation is different from the second degree of fluence attenuation.

6 . The method of claim 1 , comprising modulating a current of the X-ray source.

7 . The method of claim 6 , wherein the modulation is generated based on the region of interest.

8 . The method of claim 6 , wherein the modulation is a function of X-ray attenuation characteristics of the imaging target only for X-rays that pass through the region of interest.

9 . The method of claim 8 , wherein the modulation function is obtained based on equalizing an average value of an inverse square root of a photon count in the region of interest over a range of view angles.

10 . The method of claim 3 , wherein geometry of the filter is selected using at least one of: age, sex, body mass index, race, or ethnicity of a person.

11 . The method of claim 1 , wherein the region of interest is a heart.

12 . A computed tomography (CT) scanner, comprising:
an X-ray source; and a beam-shaping filter disposed between the X-ray source and a location where a region of interest of an imaging target is placed, wherein:
the CT scanner is configured such that an isocenter of the CT scanner is proximate to the region of interest, wherein the CT scanner is further configured to adjust a fluence of X-ray radiation produced by the X-ray source using the beam-shaping filter, and
wherein the beam-shaping filter is configured to attenuate the X-ray radiation on areas of the imaging target located outside of the region of interest and, at the same time, transmit the X-ray radiation to the areas of the imaging target located outside of the region of interest to provide a fluence of the X-ray radiation on the areas of the imaging target located outside of the region of interest at a level less than a predetermined fraction of a fluence of the X-ray radiation within the region of interest.

13 . The computed tomography scanner of claim 12 , wherein the scanner is configured such that the isocenter of the scanner is within the region of interest.

14 . The computed tomography scanner of claim 12 , wherein the beam-shaping filter is a static filter.

15 . The computed tomography scanner of claim 12 , wherein the beam-shaping filter is configured to attenuate the fluence of X-ray radiation produced by the X-ray source as a function of a distance from the isocenter.

16 . The computed tomography scanner of claim 15 , wherein the beam-shaping filter is configured to provide a first degree of fluence attenuation for the distances from the isocenter within a first range of distances and provide a second degree of fluence attenuation for the distances from the isocenter outside the first range of distances, wherein the first degree of fluence attenuation is different from the second degree of fluence attenuation.

17 . The computed tomography scanner of claim 12 , wherein the scanner is configured to modulate a current of the X-ray source.

18 . The computed tomography scanner of claim 17 , wherein the modulation is a function of X-ray attenuation characteristics of the imaging target only for X-rays that pass through the region of interest.

19 . The computed tomography scanner of claim 17 , wherein the scanner is configured to obtain the modulation function based on equalizing an average value of an inverse square root of a photon count in the region of interest over a range of view angles.

20 . The computed tomography scanner of claim 12 , wherein the region of interest is a heart.

Assignees

• Univ California

Inventors

• Contijoch Francisco
• Colvert Brendan
• Mcveigh Elliot

Classifications

• G21K1/10

  Scattering devices; Absorbing devices; Ionising radiation filters · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• A61B6/4035

  the source being combined with a filter or grating · CPC title

• A61B6/542 Primary

  involving control of exposure · CPC title

• A61B6/503

  for diagnosis of the heart · CPC title