CBCT (cone beam computed tomography) reconstruction method and system

Abstract

The invention provides a CBCT (cone beam computed tomography) reconstruction method. The CBCT reconstruction method includes the following steps that: on the Z-axis direction of a global coordinate system, the interval between two adjacent reconstruction slices is set to equal to M times of the interval between two adjacent position points of a ray source, wherein M is a non-negative integer; the ray source is utilized to obtain k frames of projection data; and if the projection data are a part of contribution for a current reconstruction slice, a critical array is established for the boundary of the reconstruction range of the current reconstruction slice according to current projection data, and back projection operation is performed on each frame of projection data according to the critical array and the current projection data. The invention also provides a CBCT reconstruction system. The CBCT reconstruction system comprises a presetting module, a data acquisition module and a back projection reconstruction module. The invention further provides a CBCT system. The CBCT system comprises a radiation source, a detector, an upper computer and an FPGA accelerating circuit. With the CBCT reconstruction method and system of the invention adopted, the calculation amount of the system is simplified, and the efficiency of the back projection operation can be improved, the complexity of the system can be reduced, and FPGA implementation can be achieved with easiness.

Description

technical field [0001] The present invention relates to the field of imaging technology, in particular to a CBCT reconstruction method and system. Background technique [0002] CBCT (cone beam computed tomography) is cone beam CT. Its ray beam is cone-shaped. Compared with traditional parallel beam and fan beam CT (Computed Tomography), it has fast scanning speed, high image resolution, high radiation utilization rate, and isotropic space. Therefore, it is widely used in fields such as oral medicine and radiation therapy. [0003] CBCT reconstruction algorithms can be divided into approximate reconstruction algorithms and exact reconstruction algorithms according to the degree of accuracy. Among them, the approximate reconstruction algorithm is represented by the FDK (Feldkamp-Davis-Kress) algorithm. The trajectory of the reconstruction algorithm is a circle, which is simple in mathematics and easy to implement. When the cone angle is less than 5°, it can well suppress Art...

AI Technical Summary

Problems solved by technology

However, the use of computer clusters to accelerate the reconstruction algorithm is costly and difficult to break through the bottleneck of the general-purpose processor itself, which is not suitable for clinical applications

Although the GPU can accelerate the parallel processing of data through a large number of computing units (stream processors), it is quite effective in accelerating the parallelization of algorithms, but the GPU is of little help to the work that itself cannot be parallelized with high threads.

At the same time, the FPGA implementation of the Katsevich algorithm is based on the existing PI line and Tam window theory, and no new solution is proposed.

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