Method for coded-source phase contrast X-ray imaging

Patent metadata

Field	Value
Publication number	US-10045752-B2
Application number	US-201314400703-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	May 14, 2012
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

Described here is a method for performing phase contrast imaging using an array of independently controllable x-ray sources. The array of x-ray sources can be controlled to produce a distinct spatial pattern of x-ray radiation and thus can be used to encode phase contrast signals without the need for a coded aperture. The lack of coded aperture increases the flexibility of the imaging method. For instance, because a fixed, coded aperture is not required, the angular resolution of the imaging technique can be increased as compared to coded-aperture imaging. Moreover, the lack of a radioopaque coded aperture increases the photon flux that reaches the subject, thereby increasing the attainable signal-to-noise ratio.

First claim

The invention claimed is:

1. A method for phase contrast imaging using an array of independently controllable x-ray sources, the steps of the method comprising:
a) directing an array of independently controllable x-ray sources to produce x-ray radiation in a distinct spatial pattern by selectively energizing the independently controllable x-ray sources in the array;
b) detecting phase-contrast signals of the x-ray radiation after the x-ray radiation passes through a subject using an x-ray detector; and
c) reconstructing an image of the subject by performing a compressed sensing reconstruction technique on the detected phase-contrast signals, wherein the reconstructed image depicts an image contrast indicative of phase shifts in the x-ray radiation.

2. The method as recited in claim 1 , in which each x-ray source of the array of independently controllable x-ray sources has a focal spot sized less than twenty micrometers.

3. The method as recited in claim 1 , in which the x-ray detector is separated from the subject by at least one meter.

4. The method as recited in claim 1 , in which the x-ray detector has an effective detector pitch of less than ten micrometers.

5. The method as recited in claim 1 , in which the distinct spatial pattern is selected as at least one of a uniformly redundant array (URA) and a modified uniformly redundant array (MURA).

6. The method as recited in claim 1 , in which step c) includes determining a target image, X, that minimizes an objective function defined as, ∥ΨX∥ 1 ; wherein Ψ is a sparsifying transform that transforms the target image, X, into a sparse domain.

7. The method as recited in claim 6 , in which the sparsifying transform is a discrete gradient transform.

8. The method as recited in claim 1 , in which the subject is at least one of a human and an animal.

9. The method as recited in claim 1 , in which the subject is at least one of a piece of luggage and a cargo container.

10. The method as recited in claim 9 , in which the at least one of a piece of luggage and a cargo container includes an explosive, and the method further comprises identifying the explosive by analyzing the image reconstructed in step c).

Assignees

• Gupta Rajiv
• Velasquez Garcia Luis Fernando
• Lanza Richard
• Horn Berthold K P
• Akinwande Akintunde Ibitayo
• Massachusetts Gen Hospital
• Massachusetts Inst Technology

Inventors

• Gupta Rajiv
• Velasquez-Garcia Luis Fernando
• Lanza Richard
• Horn Berthold K P
• Akinwande Akintunde Ibitayo

Classifications

• H01J35/186

  used as targets or X-ray converters · CPC title

• H01J2235/068

  Multi-cathode assembly · CPC title

• H01J2235/062

  Cold cathodes · CPC title

• H01J35/025

  X-ray tubes with structurally associated circuit elements · CPC title

• A61B6/484 Primary

  involving phase contrast X-ray imaging · CPC title