X-Ray CT Imaging Geometry for Needle-Tip Artifact Reduction
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Solution Overview
Problem
Current CT imaging systems suffer from severe image artifacts at the tip of needle-like probes due to photon starvation caused by metal needles, which obstruct x-ray transmission and obscure the region of interest, and existing artifact reduction methods introduce additional errors or require dual energy imaging not available in many machines.
Innovation Solution
Acquire tomographic projection data in an acquisition plane angled with respect to the probe's insertion axis, allowing for automatic gantry angulation and dynamic adjustment of the acquisition plane to reduce image artifacts by minimizing the length and size of the artifact in the image plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CT imaging is used to guide needle insertion, then the target can be visualized and aligned, but severe image artifacts are generated at the needle tip that obscure the region of interest
Solution Approach 1:
The patent applies dimensional change by acquiring CT data in an acquisition plane that is angled relative to the probe insertion trajectory plane. This transforms the imaging approach from a single-plane view to a multi-plane perspective, allowing the x-ray beams to pass alongside the probe rather than through it, thereby reducing photon starvation artifacts while maintaining target visualization capability
Solution Approach 2:
The patent changes the acquisition parameter by tilting the acquisition plane at a specific angle (e.g., 15-30 degrees) relative to the probe insertion trajectory. This parameter modification allows the x-ray beams to be positioned at angles that minimize interaction with the metallic probe, reducing artifact generation while preserving imaging quality for target alignment
2Object-generated harmful factors
If the acquisition plane is angled with respect to the probe insertion axis, then image artifacts are reduced, but the system complexity increases
Solution Approach 1:
The patent implements dynamics by enabling dynamic adjustment of the acquisition plane angle during the probe insertion process. The system can adapt the angulation in real-time based on the probe's position and trajectory, allowing optimization of artifact reduction at different stages of insertion without requiring manual intervention or complex pre-planning
3Object-generated harmful factors
If conventional artifact reduction methods are used, then some artifact reduction is achieved, but additional errors are introduced or dual energy imaging is required
Solution Approach 1:
The patent extracts the harmful interaction between x-rays and the metallic probe by changing the geometric relationship between the x-ray beam path and the probe. Instead of having x-rays pass through the probe (which causes photon starvation and artifacts), the acquisition plane is angled so that x-rays pass alongside the probe, effectively removing the source of the artifact without requiring complex correction algorithms or additional energy imaging
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Substantially reduces image artifacts at the probe tip while maintaining clear visualization of the probe trajectory, accommodating changes in probe trajectory, and eliminating the need for additional trajectory-defining steps or inputs from physicians.
Implementation Method 1
an x-ray source and x-ray detector opposed along an x-ray axis and supported to orbit in opposition about a rotational axis to collect tomographic projection data
Implementation Method 2
the tomographic projection data comprising measured x-ray attenuation along multiple rays over a range of rotational angles
Data Source
AI summary
Tomographic projection data is acquired in an acquisition plane angled with respect to a trajectory plane of a probe, such as a biopsy probe, to reconstruct an image in the trajectory plane, reducing probe-induced artifacts at the tip of the probe. Patient table position and angulation may be adjusted automatically and dynamically during probe insertion for this purpose.