X-ray detection method and X-ray detector

Patent metadata

Field	Value
Publication number	US-10724969-B2
Application number	US-201816175796-A
Country	US
Kind code	B2
Filing date	Oct 30, 2018
Priority date	May 5, 2016
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

An X-ray detection method and an X-ray detector are provided. The X-ray detection method according to embodiments of the present disclosure includes: dividing an energy range of photons emitted by an X-ray source into a number N of energy windows, where N is an integer greater than 0; obtaining a weighting factor for each of the number N of energy windows based on linear attenuation coefficients of a substance of interest and a background substance of an imaging target; obtaining a weighting factor matrix for M output channels of an X-ray detector based on the weighting factor for each of the number N of energy windows, where M is an integer greater than 0; and obtaining output results of the M output channels based on the weighting factor matrix and numbers of photons having an energy range falling into individual energy windows of the number N of energy windows.

First claim

What is claimed is:

1. An X-ray detection method, comprising:
receiving photons emitted by an X-ray source;
dividing an energy range of the photons emitted by the X-ray source into a number N of energy windows respectively corresponding to N energy window discriminators, where N is an integer greater than 0;
obtaining a weighting factor for each of the number N of energy windows based on linear attenuation coefficients of a substance of interest and a background substance of an imaging target;
obtaining a weighting factor matrix for M output channels of an X-ray detector based on the weighting factor for each of the number N of energy windows, where M is an integer greater than 0;
counting, via each of the N energy window discriminators, a number of photons that are emitted by the X-ray source and have an energy range falling into a respective energy window of the energy window discriminator; and
obtaining output results of the M output channels based on the weighting factor matrix and the counted numbers of photons having an energy range falling into individual energy windows of the number N of energy windows,
wherein for a k-th output channel of the M output channels, the X-ray detection method further comprises:
obtaining a weighting factor corresponding to an i-th energy window of the number N of energy windows and the k-th output channel in the weighting factor matrix by normalizing the weighting factor for the i-th energy window, when the i-th energy window belongs to the k-th output channel; and
setting the weighting factor corresponding to the i-th energy window and the k-th output channel in the weighting factor matrix to be 0, when the i-th energy window does not belong to the k-th output channel, where both i and k are integers greater than 0.

2. The X-ray detection method of claim 1 , wherein the obtaining the output results of the M output channels comprises multiplying the weighting factor matrix by a column vector consisting of the numbers of photons having the energy range falling into the individual energy windows of the number N of energy windows.

3. The X-ray detection method of claim 1 , wherein for an i-th energy window of the number N of energy windows, the X-ray detection method further comprises:
integrating the linear attenuation coefficient of the substance of interest and the linear attenuation coefficient of the background substance respectively within an energy range of the i-th energy window; and
calculating the weighting factor for the i-th energy window by carrying out an addition operation with an integration result of the linear attenuation coefficient of the substance of interest and an integration result of the linear attenuation coefficient of the background substance, where i is an integer greater than 0.

4. The X-ray detection method of claim 1 , wherein for an i-th energy window of the number N of energy windows, the X-ray detection method further comprises:
calculating the weighting factor for the i-th energy window based on the linear attenuation coefficient of the substance of interest, the linear attenuation coefficient of the background substance, an energy spectrum of X-rays emitted by the X-ray source in the i-th energy window, an average thickness of the substance of interest penetrated by the X-rays emitted by the X-ray source, and an average thickness of the background substance penetrated by the X-rays emitted by the X-ray source, where i is an integer greater than 0.

5. An X-ray detector, comprising:
N energy window discriminators, each of which receives photons emitted by an X-ray source and counts a number of photons that are emitted by the X-ray source and have an energy range falling into a discrimination range of the energy window discriminator;
N sets of multipliers, each of which includes M multipliers, wherein a k-th multiplier in an i-th set of multipliers is configured to multiply the number of photons counted by an i-th energy window discriminator of the N energy window discriminators by a weighting factor at a k-th row and an i-th column of an M×N weighting factor matrix, where M, N, k and i are all integers greater than 0; and
M adders, wherein a k-th adder of the M adders is configured to accumulate products obtained at the k-th multipliers of individual sets of multipliers so as to obtain an output result of a k-th output channel of M output channels of the X-ray detector,
wherein the weighting factor matrix is obtained based on linear attenuation coefficients of a substance of interest and a background substance of an imaging target; and
the X-ray detector further comprises a matrix obtaining unit configured to obtain a weighting factor for each of N energy windows based on the linear attenuation coefficient of the substance of interest and the linear attenuation coefficient of the background substance, and obtain the weighting factor matrix based on the weighting factor for each of the N energy windows,
wherein the matrix obtaining unit is further configured to:
for the k-th output channel of the M output channels:
obtain a weighting factor corresponding to an i-th energy window of the N energy windows and the k-th output channel in the weighting factor matrix by normalizing the weighting factor for the i-th energy window, when the i-th energy window belongs to the k-th output channel; and
set the weighting factor corresponding to the i-th energy window and the k-th output channel in the weighting factor matrix to be 0, when the i-th energy window does not belong to the k-th output channel.

6. The X-ray detector of claim 5 , wherein the matrix obtaining unit is further configured to:
for an i-th energy window of the N energy windows, integrate the linear attenuation coefficient of the substance of interest and the linear attenuation coefficient of the background substance respectively within an energy range of the i-th energy window; and
calculate the weighting factor for the i-th energy window by carrying out an addition operation with an integration result of the linear attenuation coefficient of the substance of interest and an integration result of the linear attenuation coefficient of the background substance.

7. The X-ray detector of claim 5 , wherein the matrix obtaining unit is further configured to: for an i-th energy window of the N energy windows, calculate the weighting factor for the i-th energy window based on the linear attenuation coefficient of the substance of interest, the linear attenuation coefficient of the background substance, an energy spectrum of X-rays emitted by the X-ray source in the i-th energy window, an average thickness of the substance of interest penetrated by the X-rays emitted by the X-ray source, and an average thickness of the background substance penetrated by the X-rays emitted by the X-ray source, where i is an integer greater than 0.

Assignees

• Univ Tsinghua
• Nuctech Co Ltd

Inventors

• Xing Yuxiang
• Guo Xiaoyue
• Deng Zhi
• Shen Le
• Zhang Li
• Chen Zhiqiang
• Li Liang

Classifications

• A61B6/4241

  using energy resolving detectors, e.g. photon counting · CPC title

• A61B6/5205

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

• G01N23/046

  using tomography, e.g. computed tomography [CT] · CPC title

• G01N23/04 Primary

  and forming images of the material · CPC title

• G01N2223/419

  computed tomograph · CPC title