X-ray Pivoting Control for Moving Object Reconstruction
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Solution Overview
Problem
Current X-ray equipment, such as angiography systems and C-arm equipment, face challenges in achieving accurate three-dimensional reconstructions of moving objects like the heart due to long pivoting times, leading to reduced reconstruction accuracy and contrast, especially when using symbolic reconstruction methods or compensating for object movement.
Innovation Solution
An operating method for X-ray equipment that pivots an X-ray arrangement rapidly between angular positions, storing projections and corresponding angular positions, and using phase signals to select projections for accurate reconstruction, allowing for three-dimensional reconstruction even with longer pivoting times by optimizing projection recording and evaluation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the X-ray arrangement is pivoted rapidly to reduce pivoting time, then the temporal resolution is improved, but the reconstruction accuracy and contrast are worsened due to motion blur and insufficient projections
Solution Approach 1:
The system performs preliminary actions by storing multiple projections at different angular positions during the pivoting process, even before the final reconstruction is needed. These pre-acquired projections are then selectively used in the reconstruction algorithm to maintain accuracy despite rapid pivoting speeds
Solution Approach 2:
The invention applies dynamics by adapting the projection selection and reconstruction process to the actual pivoting speed and motion characteristics of the object. The system dynamically adjusts which projections are used based on the cardiac cycle phase and pivoting velocity, optimizing the balance between speed and accuracy
2Productivity
If the pivoting time is reduced to capture cardiac cycles, then the productivity is improved, but the X-ray load on the patient increases due to more frequent exposures
Solution Approach 1:
The system implements periodic action by synchronizing the X-ray recording with the cardiac cycle phases. Projections are selectively recorded only during specific phases (e.g., diastole) when the heart is relatively stationary, rather than continuously throughout the entire cycle. This reduces the total X-ray load while maintaining sufficient data for reconstruction
Solution Approach 2:
The invention maintains continuity of useful action by ensuring that projections are continuously acquired during the pivoting process, but only the necessary portions are used for reconstruction. The system continuously monitors the cardiac phase and pivoting position to determine when projections are most useful, maintaining data flow while minimizing unnecessary radiation
3Device complexity
If symbolic reconstruction methods are used to simplify processing, then the device complexity is reduced, but the reconstruction quality and contrast are worsened
Solution Approach 1:
The system applies segmentation by dividing the reconstruction process into distinct phases: projection acquisition, projection selection based on cardiac phase, and reconstruction. This segmentation allows the use of simpler reconstruction algorithms for specific phases while maintaining overall quality through the structured approach
Solution Approach 2:
The invention implements local quality by applying different reconstruction strategies to different parts of the cardiac cycle and different angular positions. Rather than using a single uniform method, the system selects and processes projections differently based on the specific cardiac phase and geometric conditions, optimizing quality where needed while simplifying where appropriate
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 method enables improved three-dimensional reconstructions of moving objects with enhanced contrast and local resolution, minimizing X-ray load and reducing artifacts, by strategically selecting and processing projections during the heart's cardiac cycle.
Implementation Method 1
an X-ray source (3) and an X-ray detector (4) which diametrically oppose one another relative to the pivot axis (5)
Data Source
AI summary
A control device pivots an X-ray arrangement repeatedly between two final angular positions about a pivot axis. Projections of an object arranged in the region of the pivot axis and moving iteratively are detected at a plurality of angular positions and supplied to the control device. The control device also receives a phase position referring to the object and assigns the phase position to each projection. A computer selects one or more projections whose phase position corresponds at least approximately to a reconstruction phase position. If the computer has selected one projection for an angular position, it determines this projection as a reconstruction projection. If the computer has selected a plurality of projections for an angular position, it detects the reconstruction projection using these projections. The computer then detects a three-dimensional reconstruction of the object based on the reconstruction projection.