Unconstrained CBCT system hardening correction method and device, and medium

Abstract

The invention discloses an unconstrained CBCT system hardening correction method and device, and a medium. The method comprises the following steps: acquiring an air projection image and a projection image of a special correction die body; according to the air projection image and the projection image of the special correction die body, calculating a die body pluripotent line integral image; calculating forward projection geometric parameters according to the multi-energy line integral image of the die body; performing forward projection on the special correction die body according to the forward projection geometric parameters to obtain a target image and a target index; according to the target image and the motif multi-energy line integral image, determining a mapping relation from multi-energy projection to single-energy projection; and performing hardening correction on the multi-energy projection image according to the mapping relation. The method and the device are wide in applicability and high in robustness, and can be widely applied to the technical field of computed tomography.

Description

technical field [0001] The invention relates to the technical field of computed tomography, in particular to an unconstrained CBCT system sclerosis correction method, device and medium. Background technique [0002] Cone Beam Computed Tomography (CBCT) is widely used in dental diagnosis, image-guided radiation therapy and other medical fields. The X-ray source can only produce multi-energy rays. When penetrating the imaging object, more low-energy soft rays are absorbed by the object, and the average energy of the beam increases, resulting in hardening artifacts in the reconstructed image. [0003] The hardening correction methods of conventional CBCT systems mainly include fitting method and iterative method. The fitting method generally collects and reconstructs the uniform water model projection, obtains the three-dimensional outline of the object and performs forward projection, so as to obtain the multi-energy fitting curve between the penetration path and the original...

AI Technical Summary

Problems solved by technology

The iterative method has a better correction effect, but its setting of the objective function is relatively strict, and it is easy to fall into a local solution

[0004] In addition, the two mainstream hardening correction methods are only suitable for artifact correction of small objects or large field of view (Filed of View, FOV) CBCT systems

When the correction phantom is large or the FOV of CBCT is small, the reconstructed image will be "truncated", and the complete object outline cannot be obtained, resulting in a huge difference between the beam penetration path and its real path (or truncation artifacts that affect iterative search. Excellent), the conventional hardening correction method is limited to FOV, it is difficult to implement in the CBCT system with small FOV

Images