C-Arm Rotation Trajectory for Artifact-Reduced 3D Imaging
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Solution Overview
Problem
Existing C-arm imaging systems face limitations in capturing large imaging regions due to limited detector size, leading to image truncation artifacts and non-reproducible geometrical inaccuracies, particularly in ceiling-suspended systems, which result in time delays and image artifacts during 3D reconstruction.
Innovation Solution
A method for controlling a C-arm system that performs a forward leg rotation with a monotonically reducing lateral offset and a return leg rotation with a monotonically increasing offset, ensuring the end point of the forward leg corresponds to the start point of the return leg, maintaining consistent lateral direction, and allowing for symmetrical angle ranges to capture image data from different directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional trajectory with laterally displaced isocenter is used for C-arm rotation, then large 3D imaging regions can be achieved, but time delays occur between forward and return legs and geometrical inaccuracies lead to image artifacts
Solution Approach 1:
The C-arm is pre-positioned at an angled start position (e.g., 10-20 degrees lateral offset) before data acquisition begins. This preliminary positioning allows the continuous rotation trajectory to start and end at identical positions without requiring system movement between legs, eliminating time delays while maintaining large imaging coverage
Solution Approach 2:
The patent implements a continuous dynamic rotation trajectory where the C-arm rotates smoothly from a lateral start position through the anterior-posterior view to an angled end position, then continues rotating to return to the start position. This dynamic continuous motion eliminates discrete leg transitions and associated time delays, achieving seamless data acquisition
2Area of stationary object
If a conventional trajectory with laterally displaced isocenter is used for C-arm rotation, then large 3D imaging regions can be achieved, but non-reproducible geometrical inaccuracies occur leading to image artifacts
Solution Approach 1:
The patent employs an asymmetric rotation trajectory that starts and ends at the same angled position rather than returning to a centered position. This asymmetric path design ensures consistent lateral movement direction throughout the rotation, eliminating the direction changes that cause geometrical inaccuracies in symmetric conventional trajectories
Solution Approach 2:
The C-arm performs continuous rotation through more than 180 degrees without reversing direction or changing lateral movement orientation. This continuous unidirectional rotation maintains consistent geometrical relationships throughout the acquisition, eliminating the non-reproducible inaccuracies that occur when movement direction changes during conventional leg-based trajectories
3Productivity
If the C-arm performs conventional leg-based rotation with direction changes, then imaging can be completed, but the change in lateral movement direction causes non-reproducible geometrical inaccuracies
Solution Approach 1:
The system dynamically adjusts the rotation trajectory to maintain continuous unidirectional movement through angled start and end positions, eliminating the static leg-based approach with direction reversals. This dynamic continuous rotation ensures consistent geometrical accuracy while completing the imaging task
Data Source
AI summary
A method for controlling a C-arm of a C-arm system includes performing a forward leg of a rotation of the C-arm, wherein the forward leg starts at a start position of the forward leg of the C-arm with a lateral offset having a first offset value, and the C-arm is rotated in the forward direction as far as an end position of the forward leg, with the lateral offset being reduced to 0. In addition, a return leg of a rotation of the C-arm is performed, wherein the return leg starts at the end position of the forward leg, and the C-arm is rotated in the return direction as far as an end position of the return leg, with the lateral offset being increased in the opposite direction to the lateral offset of the forward leg up to a second offset value at the end position of the return leg.