C-arm Control Protocol Using Tilted Trajectory for Artifact Reduction
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Solution Overview
Problem
C-arm systems used for computed tomography imaging often produce image artifacts due to shadowing effects from high attenuation objects and expose radiation-sensitive areas to high intensity radiation, particularly when imaging the head of a patient.
Innovation Solution
A control protocol for a C-arm system that includes a sequence of roll angles and propeller angles, allowing the radiation source to follow a trajectory with a circular component in a tilt plane, which reduces exposure to high attenuation objects and sensitive areas, thereby improving image quality and minimizing radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radiation source follows a circular trajectory in a vertical plane around the patient, then the C-arm system can acquire projection data for CT image reconstruction, but image artifacts occur due to shadowing effects from high attenuation objects like teeth and radiation-sensitive areas are exposed to high intensity radiation
Solution Approach 1:
The patent introduces a tilt angle dimension to the traditional circular trajectory. Instead of rotating solely in a vertical plane, the C-arm system now operates in a tilted plane defined by propeller angles and roll angles, where the roll axis is tilted by a specific angle relative to the vertical direction. This dimensional change allows the radiation source to bypass high attenuation objects and reduce exposure to radiation-sensitive areas while maintaining complete coverage of the region of interest for accurate CT reconstruction
2Productivity
If the radiation source follows a circular trajectory in a vertical plane, then projection data can be acquired for image reconstruction, but high attenuation objects cause shadowing effects and image artifacts
Solution Approach 1:
By tilting the rotation plane away from the vertical axis, the patent creates a new trajectory dimension that allows the radiation source to circumvent high attenuation objects such as teeth. The tilted trajectory maintains the circular motion necessary for complete projection data acquisition while changing the spatial relationship between the radiation source and attenuating objects, thereby eliminating shadowing effects and improving image quality
3Ease of operation
If a traditional vertical plane rotation is used, then the imaging procedure is simple to implement, but radiation-sensitive areas are exposed to high intensity radiation
Solution Approach 1:
The patent modifies the trajectory parameters by introducing a tilt angle to the rotation plane. The control system adjusts the roll angles and propeller angles according to predetermined tilt parameters, changing the spatial orientation of the radiation source trajectory. This parameter change reduces radiation exposure to sensitive areas while maintaining a systematic and automated imaging procedure that remains operationally simple through computerized control
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 the acquisition of high-quality computed tomographic images while reducing radiation exposure to sensitive areas, minimizing artifacts, and ensuring safe and effective imaging procedures.
Implementation Method 1
an X-ray source and an X-ray detector for the acquisition of the projection images of the object
Data Source
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AI summary
The invention relates to an apparatus for determining a control protocol for controlling a C-arm system comprising a radiation source. The control protocol comprises a sequence of roll angles and a sequence of propeller angles. The apparatus comprises a tilt plane providing unit for providing a tilt plane tilted with respect to a vertical plane, and a control protocol determining unit for determining a control protocol by determining the sequence of roll angles and the sequence of propeller angles such that the radiation source follows a trajectory that comprises a circular component in the tilt plane and that allows the C-arm system to acquire projection data for image reconstruction. The apparatus allows to acquire computed images, for instance tomographic images, with an improved quality and to reduce radiation in radiation-sensitive areas.