Computed tomography based on linear scanning

Patent metadata

Field	Value
Publication number	US-9730657-B2
Application number	US-201414573967-A
Country	US
Kind code	B2
Filing date	Dec 17, 2014
Priority date	Dec 17, 2013
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

Imaging methods and imaging systems are provided. Methods and systems of the subject invention can include linearly translating a source and a detector. The source and the detector can be moved in opposite or approximately opposite directions. Acquired data can be used to reconstruct a tomographic image by using, for example, a compressive sensing technique.

First claim

What is claimed is:

1. An imaging method, comprising:
positioning an X-ray source on a first side of a subject to be imaged such that the X-ray source faces the subject;
positioning a detector on a second side of the subject such that the detector faces the subject;
linearly translating the X-ray source and the detector by simultaneously moving the X-ray source and the detector in opposite or approximately opposite directions while the X-ray source supplies X-rays and the detector acquires tomographic data of the subject; and
reconstructing a Computed Tomography (CT) image based on the tomographic data
wherein linearly translating the X-ray source and the detector is performed twice, and
wherein a first path traveled by the X-ray source during the first linear translation step is orthogonal to a second path traveled b the X-ray source during the second linear translation step.

2. The imaging method according to claim 1 , wherein the subject is a human patient.

3. The imaging method according to claim 1 , wherein an entire length of the first path traveled by the X-ray source during the first linear translation step is equal to an entire length of the second path traveled by the X-ray source during the second linear translation step and an entire length of a third path traveled by the X-ray source during a third linear translation step.

4. The imaging method according to claim 1 , wherein reconstructing a CT image based on the tomographic data comprises:
modeling the acquired data as a linear matrix equation (b) based on a pixel basis;
modeling the CT image to be reconstructed as a linear matrix equation (X) based on a pixel basis; and
performing the following algorithm:
step 1—input data: b and let X=0;
step 2—calculate the current image;
step 3—minimize the total variation (TV) of the current image X; and
step 4—go to step 2 until a stopping criterion is met.

5. An imaging method, comprising:
positioning an X-ray source on a first side of a subject to be imaged such that the X-ray source faces the subject;
positioning a detector on a second side of the subject such that the detector faces the subject;
linearly translating the X-ray source and the detector by simultaneously moving the X-ray source and the detector in opposite or approximately opposite directions while the X-ray source supplies X-rays and the detector acquires tomographic data of the subject; and
reconstructing a Computed Tomography (CT) image based on the tomographic data,
wherein reconstructing a CT image based on the tomographic data comprises:
modeling the acquired data as a linear matrix equation (b) based on a pixel basis;
modeling the CT image to be reconstructed as a linear matrix equation (X) based on a pixel basis; and
performing the following algorithm:
step 1—input data: b and let X=0
step 2—calculate the current image;
step 3—minimize the total variation (TV) of the current image X; and
step 4—no to step 2 until a stopping criterion is met,

wherein step 2—calculate the current image comprises calculating the image using the following equation:

X
n

(

k
+
1

)

=

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n

(
k
)

+

∑

m
∈

B

[

k
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T

]

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n

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(
k
)

a

m
+

where α m+ ≡Σ n=1 N α mn ≠α +n =≡Σ m=1 M α mn ≠0, and k is the iteration number
where A=(α mn ) is a system measurement matrix with m=1, . . . , M and n=1, . . . , N, where an index set is partitioned into T nonempty disjoint subsets B t ={i t 1 , . . . , i t M(t) }, and where

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6. The imaging method according to claim 5 , wherein step 3—minimizing the TV of the current image X comprises minimizing the TV of the current image X using the following formula:
X n (l+1) =X n (l) −λωυ,

where λ is a control parameter, υ=(∂∥∇X∥ 1 /∂X i,j )| Xi,j=Xi,j[k,l] is the gradient direction with respect to X i,j =X i,j [k,l], ω=max(X n (l) )/max(|υ|) is a scaling constant, and k and l are the outer and inner loop indices.

7. The imaging method according to claim 6 , wher

Assignees

• Wang Ge
• Liu Fenglin
• Cong Wenxiang
• Yu Hengyong
• Rensselaer Polytech Inst

Inventors

• Wang Ge
• Liu Fenglin
• Cong Wenxiang
• Yu Hengyong

Classifications

• G06T12/20

  Inverse problem, i.e. transformations from projection space into object space · CPC title

• A61B6/4452

  the source unit and the detector unit being able to move relative to each other · CPC title

• A61B6/032

  Transmission computed tomography [CT] · CPC title

• A61B6/035

  Mechanical aspects of CT · CPC title

• G06T2211/436

  Limited angle · CPC title