Apparatus and method for ray scanning imaging

Patent metadata

Field	Value
Publication number	US-9448325-B2
Application number	US-201214129655-A
Country	US
Kind code	B2
Filing date	Dec 31, 2012
Priority date	Mar 9, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

The present invention discloses apparatus and method for ray scanning imaging. The apparatus comprises a plurality of ray generators and a ray detection device. The plurality of ray generators are arranged uniformly along a circular arc and emit ray beams in sequence or simultaneously to an object to be inspected within a single scanning period. The ray detection device may be either in a multi-segmental semi-closed configuration composed of a plurality of linear arrays of ray detectors or in a circular arc configuration where a plurality of ray detectors arranged uniformly along a circular arc. During the inspection, the apparatus is advantageous in obtaining the complete ray projection values without rotation thereof, so as to effectively shorten the inspection time.

First claim

What is claimed is:

1. An apparatus for ray scanning imaging, the apparatus comprising:
a plurality of ray generators distributed uniformly along a circular arc, said plurality of ray generators emitting ray beams in sequence to an object to be inspected within a single scanning period, to complete scan for a single slice; and
a ray detection device adapted for collecting ray projection values of the ray beams emitted by said plurality of ray generators;
wherein said ray detection device comprises a plurality of linear arrays of ray detectors, each of said plurality of linear arrays of ray detectors comprises a plurality of ray detectors arranged along a straight line, wherein said plurality of linear arrays of ray detectors adjoin end to end in a same plane in sequence except that two of the plurality of linear arrays of ray detectors at both ends thereof do not adjoin each other, so as to form a semi-closed frame; and
wherein the plane where said plurality of linear arrays of ray detectors are placed and a plane where said plurality of ray generators are placed being in parallel with the plane where said plurality of linear arrays of ray detectors are placed are perpendicular to a movement direction of the object to be inspected.

2. The apparatus of claim 1 , wherein a central angle of the circular arc on which said plurality of ray generators are arranged is at least π+2γ, where 2γ is a fan angle of a fan ray beam emitted by each of the plurality of ray generators;
wherein each of the plurality of ray generators comprises at least one ray emission unit; and
wherein said ray beams are fan ray beam units composed of a plurality of straight line-shaped ray beams in parallel with each other.

3. The apparatus of claim 1 , wherein the plurality of linear arrays of ray detectors comprise more than three linear arrays of ray detectors, said more than three linear arrays of ray detectors are arranged in a manner such that an angle between two adjacent linear arrays of ray detectors is greater than π/2 and said more than three linear arrays of ray detectors are capable of detecting the ray beams emitted by all of said plurality of ray generators.

4. The apparatus of claim 1 , wherein the plurality of linear arrays of ray detectors comprise only three linear arrays of ray detectors, said three linear arrays of ray detectors are arranged in a manner such that the three linear arrays of ray detectors on both sides are all perpendicular to the middle linear array of ray detectors and said three linear arrays of ray detectors can detect the ray beams emitted by all of said plurality of ray generators.

5. The apparatus of claim 1 , wherein, the plurality of linear arrays of ray detectors corresponding to at least one of the plurality of ray generators are not arranged in a straight line that is perpendicular to a central axis of the ray beams emitted by the at least one of the plurality of ray generators;
wherein, for every one of said at least one of the plurality of ray generators, an imaging unit adopts a linear array of equidistant virtual detectors comprising a plurality of virtual detectors arranged along a straight line and distributed equidistantly, distances between all of said at least one of the plurality of ray generators and the corresponding linear array of equidistant virtual detectors are equal to one another;
wherein, said imaging unit, in accordance with connection lines between said plurality of ray generators and said plurality of linear arrays of ray detectors, determines the ray detectors corresponding to the virtual detectors, and achieves ray projection values of the virtual detectors on the basis of those of the ray detectors; and
wherein, an equidistant fan beam projection value comprises the ray projection values of the whole linear array of equidistant virtual detectors.

6. The apparatus of claim 5 , wherein said ray detectors are dual-layer dual-energy energy detectors;
wherein said imaging unit achieves an image for the object to be inspected, by, with a filtered back projection algorithm, dual-energy reconstructing dual-energy decomposition coefficients of different basis materials achieved by dual-energy decomposing the equidistant fan beam projection values or the parallel beam projection values; and
the apparatus further comprising a database adapted for storing atomic numbers and electron densities of suspicious items therein;
wherein said imaging unit determines whether the object to be inspected is suspicious item or not, by comparing distributions of atomic number and electron density of the object to be inspected that is achieved in said dual-energy reconstruction with those of suspicious items in the database.

7. A method for ray scanning imaging, the method comprising the steps of:
performing, by the apparatus according to claim 1 , a ray scanning on the object to be inspected to achieve ray projection values;
arranging a linear array of equidistant virtual detectors for every one of at least one of the plurality of ray generators which corresponds to ray detectors that are not arranged in a straight line perpendicular to a central axis of the ray beams emitted by the at least one of the plurality of ray generators, the linear array of equidistant virtual detectors comprising a plurality of virtual detectors arranged along a straight line and distributed equidistantly, distances between all of said at least one of the plurality of ray generators and the corresponding linear arrays of equidistant virtual detectors are equal to one another;
in accordance with connection lines between said plurality of ray generators and said ray detectors, determining the ray detectors corresponding to the virtual detectors, and, achieving ray projection values of the virtual detectors on the basis of those of the ray detectors; wherein, an equidistant fan beam projection value comprises the ray projection values of the whole linear array of equidistant virtual detectors.

8. The method of claim 7 , further comprising the steps of:
achieving dual-energy decomposition coefficients of different basis materials by dual-energy decomposing the equidistant fan beam projection values or the parallel beam projection values; and
achieving an image for the object to be inspected, by, with a filtered back projection algorithm, dual-energy reconstructing the dual-energy decomposition coefficients of different basis materials;
achieving distributions of atomic number and electron density of the object to be inspected; and
comparing distributions of the atomic number and the electron density of the object to be inspected with those of suspicious items stored in the database, so as to determine whether the object to be inspected is a suspicious item or not.

Assignees

• Nuctech Co Ltd
• Univ Tsinghua
• Nutech Company Ltd

Inventors

• Chen Zhiqiang
• Zhang Li
• Zhao Ziran
• Xing Yuxiang
• Hao Jia
• Li Liang

Classifications

• A61B6/4078

  Fan-beams · CPC title

• A61B6/4014

  arranged in multiple source-detector units · CPC title

• G01T1/2985

  In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); (using external radiation sources A61B6/02) · CPC title

• A61B6/032 Primary

  Transmission computed tomography [CT] · CPC title

• A61B6/4233

  using matrix detectors · CPC title