WO2017148115A1

WO2017148115A1 - Phantom projection simulation method

Info

Publication number: WO2017148115A1
Application number: PCT/CN2016/096857
Authority: WO
Inventors: 王燕妮
Original assignee: 江苏美伦影像系统有限公司
Priority date: 2016-02-29
Filing date: 2016-08-26
Publication date: 2017-09-08
Also published as: CN105719338A

Abstract

A phantom projection simulation method is characterized by comprising the following steps: 1) setting a parameter of a projection procedure detector; 2) determining a location of a source point of an X-ray and a penetration path L of the X-ray, examining CT values of all points on the path L, and determining a tissue boundary; 3) computing a power spectral distribution function and a projection result; and 4) adopting a Feldkamp algorithm to reconstruct an image. The embodiment determines the accurate tissue boundary by examining the CT values on the examination path, and increases efficiency of computing projection simulation by adopting the Feldkamp algorithm to reconstruct the image.

Description

A phantom projection simulation algorithm

Technical field

The invention relates to a phantom projection simulation algorithm and belongs to the technical field of medical image processing.

Background technique

X-ray cone beam 3D reconstruction is a hotspot in the field of medical image processing. This current method mainly needs to be improved in accuracy and computational efficiency. The algorithm involves high difficulty and long calculation time is a technology that is currently plaguing many experts. point.

Summary of the invention

In order to solve the deficiencies of the prior art, the object of the present invention is to provide a phantom projection simulation algorithm, which adopts the Feldkamp algorithm to further improve the computational efficiency of projection simulation by examining the ray path.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

A phantom projection simulation algorithm, comprising the following steps:

1) setting the parameters of the projection process detector;

2) determining the X-ray source point position and the X-ray penetration path L, examining the CT values of all points on the path L, and determining the tissue boundary;

3) calculating an X-ray energy spectrum distribution function and a projection result;

4) Reconstruct the image using the Feldkamp algorithm.

The above-described phantom projection simulation algorithm is characterized in that, in the step 1), the detector adopts a virtual XCT imaging system.

The aforementioned phantom projection simulation algorithm is characterized in that the tissue boundary appears in the step 2) It is based on the fact that the CT value of the current point is the same as the CT value of the previous point.

The aforementioned phantom projection simulation algorithm is characterized in that if a tissue boundary occurs, a boundary approximation strategy is adopted to reduce the discrete error.

The above-described phantom projection simulation algorithm is characterized in that the boundary approximation strategy continuously divides the initial step size across the boundary and decides whether to convert the moving direction until reaching a preset maximum dichotomy number, and finally at the current The position is restored to the initial step size.

The above-mentioned phantom projection simulation algorithm is characterized in that the calculation formula of the projection result in the step 3) is adopted.

Wherein, l _N represents the last boundary position of the penetration path L, and E _min and E _max are the minimum and maximum values in the energy spectrum distribution, respectively.

The beneficial effects achieved by the invention: the method determines the correct tissue boundary by examining the CT value on the path, and uses the Feldkamp algorithm to reconstruct the image, thereby improving the computational efficiency of the projection simulation.

detailed description

The invention is further described below. The following examples are only intended to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of the present invention.

The invention relates to a phantom projection simulation algorithm, comprising the following steps:

1) Set the parameters of the projection process detector. In this embodiment, the detector uses a virtual XCT imaging system.

2) Determine the X-ray source point position and the X-ray penetration path L, examine the CT value of all points on the path L, and determine the tissue boundary. The basis of the tissue boundary is that the CT value of the current point is the same as the CT value of the previous point. .

If the boundary of the tissue appears, the boundary approximation strategy is adopted to reduce the discrete error. In this embodiment, the boundary approximation strategy is to continuously divide the initial step size across the boundary and decide whether to change the moving direction until reaching The preset maximum number of dichotomies, and finally the initial step size is restored at the current position.

3) Calculating the X-ray energy spectrum distribution function and the projection result, the calculation formula of the projection result in this embodiment is adopted

4) Reconstruct the image using the Feldkamp algorithm.

The above is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention. It should also be considered as the scope of protection of the present invention.

Claims

A phantom projection simulation algorithm, comprising the following steps:

1) setting the parameters of the projection process detector;

2) determining the X-ray source point position and the X-ray penetration path L, examining the CT values of all points on the path L, and determining the tissue boundary;

3) calculating an X-ray energy spectrum distribution function and a projection result;

4) Reconstruct the image using the Feldkamp algorithm.
A phantom projection simulation algorithm according to claim 1, wherein in the step 1), the detector employs a virtual XCT imaging system.
A phantom projection simulation algorithm according to claim 1, wherein the tissue boundary appears in the step 2) based on the fact that the CT value of the current point is the same as the CT value of the previous point.
A phantom projection simulation algorithm according to claim 3, wherein if a tissue boundary occurs, a boundary approximation strategy is employed to reduce the discrete error.
A phantom projection simulation algorithm according to claim 4, wherein the boundary approximation strategy is to continuously divide the initial step size across the boundary and decide whether to switch the moving direction until the preset maximum dichotomy is reached. The number of times, and finally the initial step size is restored at the current position.
A phantom projection simulation algorithm according to claim 1, wherein the calculation formula of the projection result in the step 3) is
Wherein, l N represents the last boundary position of the penetration path L, and E min and E max are the minimum and maximum values in the energy spectrum distribution, respectively.