C-arm X-ray Trajectory Superellipse Collision Avoidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mobile cone-beam C-arm X-ray systems face challenges in recording complete 3D data sets with limited orbital adjustment ranges, leading to potential collisions and incomplete reconstructions, especially with obese patients or non-isocentric setups, resulting in poorer image quality and increased radiation exposure.
Innovation Solution
The method involves calculating and storing trajectories with rotational portions defined by piecewise superellipses to ensure collision-free movement of the C-arm, allowing for complete 3D data set recording within the central layer by adjusting the C-arm's position and orientation to maintain the central beam through the virtual scan center, even with limited adjustment ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the C-arm is moved along a circular arc trajectory to record projection images, then the orbital movement is simplified, but the central beam does not run precisely through the virtual scan center leading to incomplete 3D data sets
Solution Approach 1:
The patent transitions from a fixed circular arc trajectory to a dynamic trajectory that is continuously adjusted based on the C-arm's current position. The holder's position is adaptively modified along the orbital path to ensure the central beam always passes through the virtual scan center, making the trajectory flexible rather than rigidly circular
Solution Approach 2:
The patent changes the trajectory parameters dynamically during the scanning process. Instead of maintaining a constant circular arc radius and center, the trajectory parameters are continuously adjusted as functions of the orbital angle to ensure precise alignment of the central beam with the virtual scan center at every position
2Manufacturing precision
If the holder position is adjusted to keep the central beam through the virtual scan center, then complete 3D data is recorded, but the adjustment paths required increase the risk of collision with patient or table
Solution Approach 1:
The patent performs preliminary calculations of the optimal trajectory before the actual scanning begins. The required holder adjustments are pre-computed as functions of the orbital angle, allowing the system to plan a collision-free path in advance while still ensuring complete data acquisition
Solution Approach 2:
The patent resolves the collision risk by utilizing the vertical dimension (z-axis) in addition to horizontal adjustments. The holder can move vertically to clear obstacles while maintaining the central beam alignment, transforming a 2D positioning problem into a 3D solution space
3Object-affected harmful factors
If the C-arm orbital adjustment range is limited to avoid collisions, then safety is improved, but the ability to record complete 3D data sets is compromised
Solution Approach 1:
The patent makes the trajectory dynamic within the limited orbital range. Instead of requiring a full 360-degree rotation, the system adaptively adjusts the holder position along the available orbital arc to ensure complete data acquisition within the constrained angular range
Solution Approach 2:
The patent changes the approach from requiring large angular movement to making precise positional adjustments within a smaller angular range. The trajectory parameters are optimized to extract maximum imaging value from the limited orbital adjustment capability
4Measurement precision
If multiple adjustment axes are used to achieve precise positioning, then positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent makes the existing adjustment axes multi-functional. The same horizontal and vertical adjustment mechanisms used for positioning are also employed for trajectory correction, eliminating the need for dedicated correction mechanisms and reducing overall system complexity
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
This approach enables faster and more accurate recording of complete 3D data sets without collisions, improving image quality and reducing radiation exposure by optimizing the C-arm's trajectory to fit the patient's dimensions and table geometry.
Implementation Method 1
an X-ray beam source (3) arranged at one end of the C-arm (2) and an X-ray beam detector (4) arranged oppositely at the other end of the C-arm (2)
Data Source
AI summary
This disclosure generally relates to a method and an apparatus for recording a 3D data set of an ROI (50) complete in the central layer by using a cone-beam C-arm X-ray apparatus (1) having a cone beam (32) with a cone angle (35) in the plane of the C-arm and having a virtual scan center (51) in the center of the ROI (50), wherein the scan is performed with a trajectory pair situated in the virtual scan center (51) and composed of a focus trajectory and a detector trajectory and wherein the rotational portion (402) of the detector trajectory is formed from piece-wise defined superellipses.