CN111067561B

CN111067561B - Energy spectrum CT substance decomposition method and device, CT equipment and CT system

Info

Publication number: CN111067561B
Application number: CN201911360516.6A
Authority: CN
Inventors: 沈天浩; 楼珊珊
Original assignee: Neusoft Medical Systems Co Ltd
Current assignee: Neusoft Medical Systems Co Ltd
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2023-05-02
Anticipated expiration: 2039-12-25
Also published as: CN111067561A

Abstract

The embodiment of the invention provides an energy spectrum CT substance decomposition method, an energy spectrum CT substance decomposition device, CT equipment and a CT system. According to the embodiment of the invention, first raw data and second raw data acquired by dual-energy CT scanning of a detected object under the same view angle range are acquired, a first initial length corresponding to a first substance and a second initial length corresponding to a second substance are determined according to a first relation, the first raw data and the second raw data of mapping the dual-energy CT scanning raw data to two substance lengths, the first length and the second length are determined according to a second relation, the first initial length and the second initial length of mapping the two substance lengths to the dual-energy CT scanning raw data, and an image is built based on the first length, so that a first base image is obtained; and the second base image is obtained based on the second length, and the dual-energy decomposition is carried out by combining the data field, so that the beam hardening caused by the image field decomposition is avoided, the precision is improved, the dual-energy projection matching is not needed, the requirement on hardware is reduced, and the cost is reduced.

Description

Energy spectrum CT substance decomposition method and device, CT equipment and CT system

Technical Field

The invention relates to the technical field of medical image data processing, in particular to an energy spectrum CT substance decomposition method, an energy spectrum CT substance decomposition device, CT equipment and a CT system.

Background

Clinical application of the energy spectrum CT (Computed Tomography, electronic computer tomography) system is a significant technical advance in the field of X-ray medical imaging in recent years. Compared with the traditional CT, the energy spectrum CT can effectively remove beam hardening artifacts, optimize image quality, perform qualitative and quantitative analysis on a scanned object, and distinguish substances which cannot be distinguished by simply relying on CT values in the traditional CT, so that the effect of distinguishing the substances is achieved.

The core technology of energy spectrum CT is a dual-energy CT substance decomposition algorithm. In the related art, a dual-energy decomposition method based entirely on an image domain or a dual-energy decomposition method based entirely on a data domain is adopted. The dual-energy decomposition method based on the image domain firstly utilizes high-energy and low-energy projection to reconstruct high-energy and low-energy CT images, and then processes the high-energy and low-energy CT images to obtain physical parameter distribution images of object faults. This method cannot fundamentally eliminate the beam hardening effect and thus has lower accuracy. The dual-energy projection matching is needed by the dual-energy decomposition method based on the data field completely, so that each high-energy data and each low-energy data are sourced from the same view angle, and the requirement on hardware is high, so that the cost is high.

Disclosure of Invention

In order to overcome the problems in the related art, the invention provides an energy spectrum CT substance decomposition method, an energy spectrum CT substance decomposition device, a CT device and a CT system, which improve the precision and reduce the cost.

According to a first aspect of an embodiment of the present invention, there is provided a method for decomposing an energy spectrum CT substance, including:

acquiring first raw data and second raw data acquired by dual-energy CT scanning of a detected object under the same view angle range, wherein first energy corresponding to the first raw data is smaller than second energy corresponding to the second raw data;

according to a first relation, the first raw data and the second raw data, which are predetermined, of mapping the dual-energy CT scanning raw data to two material lengths, determining a first initial length corresponding to a first material and a second initial length corresponding to a second material;

determining a first length corresponding to the first substance and a second length corresponding to the second substance according to a second relation, the first initial length and the second initial length, which are predetermined and are used for mapping the lengths of the two substances to the dual-energy CT scanning raw data;

performing imaging based on the first length to obtain a first base image corresponding to the first substance; and performing imaging based on the second length to obtain a second base image corresponding to the second object.

According to a second aspect of an embodiment of the present invention, there is provided an energy spectrum CT substance decomposing apparatus including:

The acquisition module is used for acquiring first raw data and second raw data acquired by dual-energy CT scanning of the detected object under the same view angle range, wherein first energy corresponding to the first raw data is smaller than second energy corresponding to the second raw data;

the initial length determining module is used for determining a first initial length corresponding to a first substance and a second initial length corresponding to a second substance according to a first relation, the first raw data and the second raw data, which are predetermined and are used for mapping the dual-energy CT scanning raw data to the lengths of two substances;

the final length determining module is used for determining a first length corresponding to the first substance and a second length corresponding to the second substance according to a predetermined second relation for mapping the lengths of the two substances to the dual-energy CT scanning raw data, the first initial length and the second initial length;

the imaging module is used for carrying out imaging based on the first length to obtain a first base image corresponding to the first substance; and performing imaging based on the second length to obtain a second base image corresponding to the second object.

According to a third aspect of embodiments of the present invention, there is provided a CT apparatus comprising: an internal bus, and a memory, a processor and an external interface connected through the internal bus; wherein,,

The external interface is used for being connected with a detector of the CT system, and the detector comprises a plurality of detector chambers and corresponding processing circuits;

the memory is used for storing machine-readable instructions corresponding to spectrum CT substance decomposition logic;

the processor is configured to read the machine-readable instructions on the memory and perform operations comprising:

According to a fourth aspect of embodiments of the present invention, there is provided a CT system comprising a detector, a scan bed and a CT apparatus, the detector comprising a plurality of detector cells and corresponding processing circuitry; wherein:

the detector chamber is used for detecting X-rays passing through a scanning object and converting the X-rays into electric signals in the scanning process of the CT system;

the processing circuit is used for converting the electric signal into a pulse signal and collecting energy information of the pulse signal;

the CT device is used for:

The technical scheme provided by the embodiment of the invention can have the following beneficial effects:

according to the embodiment of the invention, first raw data and second raw data acquired by dual-energy CT scanning of a detected object under the same view angle range are acquired, a first initial length corresponding to a first substance and a second initial length corresponding to a second substance are determined according to a first predetermined relation of mapping dual-energy CT scanning raw data to two substance lengths, the first initial length and the second initial length corresponding to the second substance, and a first base image corresponding to the first substance is obtained by performing imaging based on the first length according to a second predetermined relation of mapping the two substance lengths to dual-energy CT scanning raw data, the first initial length and the second initial length; and performing imaging based on the second length to obtain a second base image corresponding to the second object, and performing dual-energy decomposition in combination with a data field, so that beam hardening caused by image field decomposition is avoided, the precision is improved, dual-energy projection matching is not required, the requirement on hardware is reduced, and the cost is reduced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the specification and together with the description, serve to explain the principles of the specification.

Fig. 1 is a schematic diagram of a CT scanning procedure.

Fig. 2 is a flowchart illustrating a method for decomposing a spectral CT substance according to an embodiment of the present invention.

FIG. 3 is an exemplary diagram of a scanning method for acquiring training data.

FIG. 4 is an exemplary diagram of training data obtained by simulation.

Fig. 5 is a functional block diagram of a spectral CT apparatus according to an embodiment of the present invention.

Fig. 6 is a hardware configuration diagram of a CT apparatus according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatus and methods consistent with aspects of embodiments of the invention as detailed in the accompanying claims.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting of embodiments of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.

It should be understood that although the terms first, second, third, etc. may be used in embodiments of the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, the first information may also be referred to as second information, and similarly, the second information may also be referred to as first information, without departing from the scope of embodiments of the present invention. The word "if" as used herein may be interpreted as "at … …" or "at … …" or "responsive to a determination", depending on the context.

Fig. 1 is a schematic diagram of a CT scanning procedure. As shown in fig. 1, the X-ray source emits X-rays that attenuate after passing through the object. The attenuated X-ray signals can be detected by a detector, the detected X-ray signals are converted into digital signals through a series of conversion and are stored in a computer disk, and the data in the disk are CT scanning data. The light source and the detector rotate around a certain center, so that CT scan data of X-rays attenuated by the object under a plurality of angles (the angles are called viewing angles) can be obtained, and the CT scan data can be converted into medical images which can be recognized by human eyes through a plurality of common mathematical methods (such as the most common filtering back projection method).

The dual-energy CT is a brand-new medical image diagnosis technology, and can solve the problem of common image of the traditional CT different diseases to a certain extent. The dual-energy CT utilizes the difference of X-ray attenuation characteristics of the object under different energies, and can obtain a single-energy image, an electron density and an effective atomic number image of the scanned object through a CT image reconstruction algorithm, thereby effectively realizing substance distinction.

The dual-energy decomposition method based on the image domain in the related art cannot fundamentally eliminate the beam hardening effect due to the inherent characteristics of the dual-energy decomposition method, so that the precision is lower. In the related art, the dual-energy decomposition method based on the data domain completely needs dual-energy projection matching, so that each high-energy data and each low-energy data are derived from the same view angle, the requirement on hardware is high, and the equipment containing the hardware with the dual-energy projection matching function is high in cost, so that the cost is high.

The method of decomposing the spectral CT substance is described in detail by way of examples.

Fig. 2 is a flowchart illustrating a method for decomposing a spectral CT substance according to an embodiment of the present invention. As shown in fig. 2, in this embodiment, the energy spectrum CT substance decomposing method may include:

s201, acquiring first raw data and second raw data acquired by dual-energy CT scanning of a detected object under the same view angle range, wherein first energy corresponding to the first raw data is smaller than second energy corresponding to the second raw data.

S202, according to a predetermined first relation of mapping dual-energy CT scanning raw data to two material lengths, the first raw data and the second raw data, determining a first initial length corresponding to a first material and a second initial length corresponding to a second material.

S203, determining a first length corresponding to the first substance and a second length corresponding to the second substance according to a predetermined second relation of mapping the lengths of the two substances to the dual-energy CT scan raw data, the first initial length and the second initial length.

S204, performing imaging based on the first length to obtain a first base image corresponding to the first substance; and performing imaging based on the second length to obtain a second base image corresponding to the second object.

In this embodiment, the first raw data and the second raw data are raw data acquired by CT scan of the same subject under the same view angle range. The first raw data is raw data acquired by CT scanning of the object under the first energy, and the second raw data is raw data acquired by CT scanning of the object under the second energy. Since the first energy is less than the second energy, the first raw data may be referred to as low energy data and the second raw data may be referred to as high energy data.

In this embodiment, the first raw data and the second raw data do not need to be matched, where matching refers to aligning the data with the same scanning angle of view in the first raw data and the second raw data, so that each pair of matched high-low energy data is derived from the same angle of view.

At present, the device with the function of matching high-energy and low-energy data of dual-energy CT scanning is very high in price, and the common device without the matching function is relatively low in price. The embodiment can be implemented by using common equipment because the high-energy data and the low-energy data do not need to be matched, and the cost is low.

In this embodiment, the first relationship and the second relationship are trained in advance.

The first relation and the second relation can be obtained by training high-low energy data of two substances under different length combinations. Each set of training data includes a first length of a first substance, a second length of a second substance, first CT scan data corresponding to the first length of the first substance, and second CT scan data corresponding to the second length of the second substance.

In the application, the training data of the first relationship and the second relationship can be obtained in various modes. Two examples of acquiring training data are listed below.

The first acquisition mode is as follows: scanning method. FIG. 3 is an exemplary diagram of a scanning method for acquiring training data. As shown in fig. 3 (a), a special two-material only model is first designed and scanned. The scan length of the model at different angles for two materials can be calculated using the geometric relationship in fig. 3 (b), each material having a length of the line segment of fig. 3 (b) where the ray lies within the material.

The second acquisition mode is as follows: simulation method. FIG. 4 is an exemplary diagram of training data obtained by simulation. As shown in the figure4, if the incident spectrum is known (the incident spectrum can be generated by the international spectrum simulation software), the equivalent filtering of the incident object before passing through (can be obtained by the formula (1), wherein only l is shown in the formula (1) _Filtration Unknown), and the object passed along the ray path and the length of the object, the attenuation of the ray after passing through the object can be calculated by using equation (2) in a simulation manner, so as to obtain the simulation value received by the detector. It is therefore only necessary to manually set different length combinations of the two substances and then simulate to obtain the required training data. The scheme does not need to design and manufacture a die body and is not limited by materials.

In the formula, T (E) is the incident intensity of X-rays; μ (E) is the equivalent filtered attenuation coefficient; l (L) _Filtration Is the length of the equivalent filtering on the ray path; l (L) _{Water and its preparation method} Is the length of water that passes through the ray path.

The training process of the first relationship and the second relationship is illustrated below.

Step1: the simulated substance 1 has a length l ₁ Raw data R obtained by low-energy CT scanning _low And the simulated substance 2 is of length l ₂ Raw data R obtained by high-energy CT scanning _high . Substance 1 and substance 2 are two different substances. Raw data R _low And R is _high Are scanned at the same viewing angle.

By data l ₁ 、l ₂ 、R _low 、R _high Rough fitting of mapping dual-energy CT scanning raw data to a first order polynomial of two substance lengths to obtain coefficient a ₁ 、b ₁ 、a ₂ 、b ₂ . The first order polynomial is the first relationship. The first order polynomial can be expressed by the following formula (3) and formula (4):

l ₁ ＝a ₁ R _low +b ₁ R _high (3)

l ₂ ＝a ₂ R _low +b ₂ R _high (4)

step2: using data l in Step1 ₁ 、l ₂ 、R _low 、R _high Accurately training multiple polynomial fitting of two substance length mapping to dual-energy CT scanning raw data to obtain two polynomials P _Low ，P _High . The fitted polynomial of degree is the second relationship. The polynomial of the degree can be expressed as follows

(5) And formula (6):

R _low ＝P _low (l ₁ ,l ₂ ) (5)

R _high ＝P _high (l ₁ ,l ₂ ) (6)

to this end, the first relationship and the second relationship may be determined.

In step S204, an image is created based on the first length and the second length, respectively, to obtain a base image corresponding to each of the first substance and the second substance. Thus, material decomposition is achieved.

In an exemplary process, the first relationship includes a first low energy coefficient and a second low energy coefficient corresponding to the first energy, and a first high energy coefficient and a second high energy coefficient corresponding to the second energy; step S202 may include:

determining first low-energy data and second low-energy data according to the first raw data, the first low-energy coefficient and the second low-energy coefficient, and determining first high-energy data and second high-energy data according to the second raw data, the first high-energy coefficient and the second high-energy coefficient;

respectively carrying out image creation based on the first low-energy data, the second low-energy data, the first high-energy data and the second high-energy data to obtain a first low-energy image, a second low-energy image, a first high-energy image and a second high-energy image;

adding the first low-energy image and the first high-energy image to obtain a first initial base image corresponding to the first substance; adding the second low-energy image and the second high-energy image to obtain a second initial base image corresponding to a second object;

and respectively carrying out orthographic projection on the first initial base image and the second initial base image to obtain a first initial length corresponding to the first substance and a second initial length corresponding to the second substance.

For example. The first life data is R _low The second raw data is R _high The first low energy coefficient and the second low energy coefficient are a in the formula (3), respectively ₁ 、a ₂ The first high energy coefficient and the second high energy coefficient are b in the formula (4) ₁ 、b ₂ Then, according to the present example, the procedure of obtaining the first initial length and the second initial length is as follows:

acquiring first life data R _low With a first low energy coefficient a ₁ Product a of (2) ₁ R _low ，a ₁ R _low As first low energy data;

acquiring first life data R _low And a second low energy coefficient a ₂ Product a of (2) ₂ R _low ，a ₂ R _low As second low energy data;

acquiring second raw data R _high And a first high energy coefficient b ₁ Product b of (2) ₁ R _high ，b ₁ R _high As first high-energy data;

acquiring second raw data R _high And a second high energy coefficient b ₂ Product b of (2) ₂ R _high ，b ₂ R _high As second high-energy data; and

based on data a respectively ₁ R _low 、a ₂ R _low 、b ₁ R _high 、b ₂ R _high Performing image creation to obtain a first low-energy image

Second low-energy image->

First high-energy image->

Second high-energy image->

Image the first low energy image

And a first high-energy image->

Adding to obtain a first initial base image +.>

Second low-energy image +.>

And a second high-energy image->

Adding to obtain second original base image +.>

For the first initial base image I' ₁ Orthographic projection is carried out to obtain a first initial length l 'corresponding to the first substance' ₁ The method comprises the steps of carrying out a first treatment on the surface of the For the second initial base image I' ₂ Orthographic projection is carried out to obtain a second initial length l 'corresponding to the second object' ₂ 。

In an exemplary implementation, determining the first low energy data and the second low energy data according to the first raw data, the first low energy coefficient, and the second low energy coefficient, and determining the first high energy data and the second high energy data according to the second raw data, the first high energy coefficient, and the second high energy coefficient includes:

acquiring the product of the first life data and the first low-energy coefficient as first low-energy data;

acquiring the product of the first life data and the second low-energy coefficient as second low-energy data;

obtaining the product of the second raw data and the first high-energy coefficient as first high-energy data;

and obtaining the product of the second raw data and the second high-energy coefficient as second high-energy data.

Detailed examples please see the aforementioned acquisition data a ₁ R _low 、a ₂ R _low 、b ₁ R _high 、b ₂ R _high Is a process of (2).

In an exemplary implementation, determining a first length corresponding to the first substance and a second length corresponding to the second substance according to a predetermined second relationship that maps lengths of two substances to dual-energy CT scan raw data, the first initial length and the second initial length;

Taking the first initial length as a first input length in a first iteration, and taking the second initial length as a second input length in the first iteration; taking the first length obtained after the j-1 th iteration as the first input length in the j-1 th iteration, and taking the second length obtained after the j-1 th iteration as the second input length in the j-1 th iteration; in each iteration, the following is performed:

determining a first length error corresponding to the first substance and a second length error corresponding to the second substance according to the second relation and the first input length and the second input length in the iteration;

determining whether a preset iteration termination condition is met currently;

if yes, stopping iteration, and determining that a first length corresponding to the first substance is equal to the sum of a first input length and a first length error, and a second length corresponding to the second substance is equal to the sum of a second input length and a second length error; if the first length and the second length are not satisfied, determining the sum of the first input length and the first length error in the current iteration as a first length, determining the sum of the second input length and the second length error in the current iteration as a second length, and entering the next iteration.

The foregoing examples are followed.

Equation (5) and equation (6) obtained by using the foregoing example, the first initial length l' ₁ Second initial length l' ₂ Calculating the length error Deltal 'of two substances by combining Taylor once expansion' ₁ 、Δl′ ₂ ；

The length error Deltal 'is calculated according to the following equation (7)' ₁ 、Δl′ ₂ ：

By using the error Deltal' ₁ 、Δl′ ₂ For a first initial length l' ₁ Second initial length l' ₂ And (5) performing correction. The modified formula is as follows formula (8):

if the length error Deltal' ₁ 、Δl′ ₂ The maximum of the two is greater than or equal to a given threshold, namely max (|Deltal' ₁ ||，||Δl′ ₂ I) is greater than or equal to threshold, then use l% ₁ 、l″ ₂ Replace l 'in the formulas (7) and (8) respectively' ₁ 、l′ ₂ The new length error and the corrected length value are recalculated.

If the length error Deltal' ₁ 、Δl′ ₂ The maximum of the two is greater than or equal to a given threshold, namely max (|Deltal' ₁ ||,Δl′ ₂ ||)<threshold, then determine l ₁ For the first length corresponding to the first substance, determine l "" ₂ A second length corresponding to the second substance.

In an exemplary implementation, the iteration termination condition includes any one of the following conditions:

the current iteration number reaches a preset number threshold;

the maximum absolute value of the first length error and the second length error obtained in the iteration is smaller than a preset length threshold value.

In one exemplary implementation, the first relationship includes:

a first order polynomial of a first energy length is obtained from the first energy data and the second energy data, and a second order polynomial of a second energy length is obtained from the first energy data and the second energy data.

For example, the first order polynomial may be the aforementioned equation (3), and the second order polynomial may be the aforementioned equation (4).

In an exemplary implementation, the second relationship includes:

a first polynomial of the first energy data is obtained from the first energy length and the second energy length, and a second polynomial of the second energy data is obtained from the first energy length and the second energy length.

For example, the first degree polynomial may be the aforementioned equation (5), and the second degree polynomial may be the aforementioned equation (6).

According to the energy spectrum CT substance decomposition method provided by the embodiment of the invention, through acquiring first raw data and second raw data acquired by dual-energy CT scanning of a detected object in the same view angle range, according to a first relation, the first raw data and the second raw data which are predetermined and are used for mapping the dual-energy CT scanning raw data to the lengths of two substances, a first initial length corresponding to the first substance and a second initial length corresponding to the second substance are determined, according to a second relation, the first initial length and the second initial length which are predetermined and are used for mapping the lengths of the two substances to the dual-energy CT scanning raw data, a first length corresponding to the first substance and a second length corresponding to the second substance are determined, and an image is built based on the first length, so that a first base image corresponding to the first substance is obtained; and performing imaging based on the second length to obtain a second base image corresponding to the second object, and performing dual-energy decomposition in combination with a data field, so that beam hardening caused by image field decomposition is avoided, the precision is improved, dual-energy projection matching is not required, the requirement on hardware is reduced, and the cost is reduced.

Based on the method embodiment, the embodiment of the invention also provides a corresponding device, equipment and storage medium embodiment.

Fig. 5 is a functional block diagram of a spectral CT apparatus according to an embodiment of the present invention. As shown in fig. 5, in the present embodiment, the spectral CT substance decomposing apparatus may include:

the acquiring module 510 is configured to acquire first raw data and second raw data acquired by performing dual-energy CT scanning on a subject under the same view angle range, where first energy corresponding to the first raw data is smaller than second energy corresponding to the second raw data;

an initial length determining module 520, configured to determine a first initial length corresponding to a first substance and a second initial length corresponding to a second substance according to a predetermined first relationship that maps dual-energy CT scan raw data to two substance lengths, the first raw data and the second raw data;

a final length determining module 530, configured to determine a first length corresponding to the first substance and a second length corresponding to the second substance according to a predetermined second relationship that maps lengths of two substances to dual-energy CT scan raw data, the first initial length and the second initial length;

An imaging module 540, configured to perform imaging based on the first length, and obtain a first base image corresponding to the first substance; and performing imaging based on the second length to obtain a second base image corresponding to the second object.

In an exemplary implementation, the first relationship includes a first low energy coefficient and a second low energy coefficient corresponding to the first energy, and a first high energy coefficient and a second high energy coefficient corresponding to the second energy;

the initial length determination module 520 may be specifically configured to:

In one exemplary implementation, the final length determination module 530 may be specifically configured to:

determining whether a preset iteration termination condition is met currently;

the current iteration number reaches a preset number threshold;

In one exemplary implementation, the first relationship includes:

In an exemplary implementation, the second relationship includes:

The embodiment of the invention also provides CT equipment. Fig. 6 is a hardware configuration diagram of a CT apparatus according to an embodiment of the present invention. As shown in fig. 6, the CT apparatus includes: an internal bus 601, and a memory 602 connected by the internal bus, a processor 603 and an external interface 604, wherein the external interface is used for connecting a detector of the CT system, and the detector comprises a plurality of detector chambers and corresponding processing circuits;

the memory 602 is configured to store machine-readable instructions corresponding to spectrum CT material decomposition logic;

the processor 603 is configured to read machine readable instructions on the memory 602 and execute the instructions to implement the following operations:

according to a predetermined first relation of mapping dual-energy CT scanning raw data to two material lengths, the first raw data and the second raw data, determining a first initial length corresponding to a first material and a second initial length corresponding to a second material, including:

In an exemplary implementation, determining the first length corresponding to the first substance and the second length corresponding to the second substance according to a predetermined second relationship that maps lengths of two substances to dual-energy CT scan raw data, the first initial length, and the second initial length includes:

determining whether a preset iteration termination condition is met currently;

the current iteration number reaches a preset number threshold;

In one exemplary implementation, the first relationship includes:

In an exemplary implementation, the second relationship includes:

The embodiment of the invention also provides a CT system, which comprises a detector, a scanning bed and CT equipment, wherein the detector comprises a plurality of detector chambers and corresponding processing circuits; wherein:

the CT device is used for:

determining whether a preset iteration termination condition is met currently;

the current iteration number reaches a preset number threshold;

In one exemplary implementation, the first relationship includes:

In an exemplary implementation, the second relationship includes:

The embodiment of the invention also provides a computer readable storage medium, on which a computer program is stored, wherein the program when executed by a processor realizes the following operations:

determining whether a preset iteration termination condition is met currently;

the current iteration number reaches a preset number threshold;

In one exemplary implementation, the first relationship includes:

In an exemplary implementation, the second relationship includes:

For the device and apparatus embodiments, reference is made to the description of the method embodiments for the relevant points, since they essentially correspond to the method embodiments. The apparatus embodiments described above are merely illustrative, wherein the modules illustrated as separate components may or may not be physically separate, and the components shown as modules may or may not be physical, i.e., may be located in one place, or may be distributed over a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purposes of the present description. Those of ordinary skill in the art will understand and implement the present invention without undue burden.

The foregoing describes specific embodiments of the present disclosure. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Other embodiments of the present description will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This specification is intended to cover any variations, uses, or adaptations of the specification following, in general, the principles of the specification and including such departures from the present disclosure as come within known or customary practice within the art to which the specification pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the specification being indicated by the following claims.

It is to be understood that the present description is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present description is limited only by the appended claims.

The foregoing description of the preferred embodiments is provided for the purpose of illustration only, and is not intended to limit the scope of the disclosure, since any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the disclosure are intended to be included within the scope of the disclosure.

Claims

1. A method of spectral CT material decomposition comprising:

according to a first relation, the first raw data and the second raw data, which are predetermined, of mapping the dual-energy CT scanning raw data to two material lengths, determining a first initial length corresponding to a first material and a second initial length corresponding to a second material; wherein the first relationship comprises: obtaining a first order polynomial of a first energy length from the first energy data and the second energy data, and obtaining a second order polynomial of a second energy length from the first energy data and the second energy data;

determining a first length corresponding to the first substance and a second length corresponding to the second substance according to a second relation, the first initial length and the second initial length, which are predetermined and are used for mapping the lengths of the two substances to the dual-energy CT scanning raw data; wherein the second relationship comprises: a first polynomial of the first energy data is obtained according to the first energy length and the second energy length, and a second polynomial of the second energy data is obtained according to the first energy length and the second energy length;

2. The method of claim 1, wherein the first relationship includes a first low energy coefficient and a second low energy coefficient corresponding to the first energy, and a first high energy coefficient and a second high energy coefficient corresponding to the second energy;

3. The method of claim 2, wherein determining first low energy data and second low energy data from the first raw data, the first low energy coefficient, the second low energy coefficient, and determining first high energy data and second high energy data from the second raw data, the first high energy coefficient, the second high energy coefficient, comprises:

4. The method of claim 1, wherein determining a first length corresponding to the first substance and a second length corresponding to the second substance from a predetermined second relationship mapping two substance lengths to dual energy CT scan raw data, the first initial length and the second initial length comprises:

determining whether a preset iteration termination condition is met currently;

5. The method of claim 4, wherein the iteration termination condition comprises any one of the following conditions:

the current iteration number reaches a preset number threshold;

6. An energy spectrum CT substance decomposing apparatus, comprising:

the initial length determining module is used for determining a first initial length corresponding to a first substance and a second initial length corresponding to a second substance according to a first relation, the first raw data and the second raw data, which are predetermined and are used for mapping the dual-energy CT scanning raw data to the lengths of two substances; wherein the first relationship comprises: obtaining a first order polynomial of a first energy length from the first energy data and the second energy data, and obtaining a second order polynomial of a second energy length from the first energy data and the second energy data;

The final length determining module is used for determining a first length corresponding to the first substance and a second length corresponding to the second substance according to a predetermined second relation for mapping the lengths of the two substances to the dual-energy CT scanning raw data, the first initial length and the second initial length; wherein the second relationship comprises: a first polynomial of the first energy data is obtained according to the first energy length and the second energy length, and a second polynomial of the second energy data is obtained according to the first energy length and the second energy length;

7. A CT apparatus, comprising: an internal bus, and a memory, a processor and an external interface connected through the internal bus; wherein,,

8. A CT system comprising a detector, a scan bed and a CT apparatus, the detector comprising a plurality of detector cells and corresponding processing circuitry; wherein:

the CT device is used for: