Retrospective Internal Gating for Respiratory Motion Correction in PET Imaging
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Solution Overview
Problem
Patient motion during medical imaging, particularly respiratory motion, leads to image degradation, blurring, and reduced detectability of small lesions or low-contrast details, limiting the accuracy of measurements.
Innovation Solution
A method for retrospective internal gating that involves acquiring images at different times, identifying temporally cyclical signals, and combining them to create a time-varying object motion function, which correlates image acquisition times with the phases of periodic motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If respiratory gating is implemented to reduce image degradation from patient motion, then image quality and lesion detectability are improved, but device complexity and procedural complexity increase due to additional hardware and gating mechanisms
Solution Approach 1:
The system uses the patient's own respiratory motion characteristics to generate gating signals. By extracting respiratory phase information from the image data itself through algorithms that analyze temporal cyclical signals, the system eliminates the need for external respiratory monitoring hardware. The gating mechanism serves itself by deriving its control signals from the motion it intends to correct.
Solution Approach 2:
The patent replaces mechanical respiratory gating devices (such as respiratory belts, cameras, or pneumatic sensors) with a software-based algorithmic approach. The gating signals are generated computationally by analyzing temporal patterns in the image data, substituting physical measurement and mechanical control systems with digital signal processing and automated algorithms.
2Reliability
If hardware-based respiratory gating devices are used to characterize patient motion, then respiratory motion can be tracked, but additional cost and procedural complexity are introduced
Solution Approach 1:
The system extracts respiratory motion information from the image data itself without requiring external sensing devices. The algorithm analyzes temporal cyclical signals within the image sequences to characterize respiratory motion, allowing the imaging system to self-monitor and self-regulate without auxiliary hardware.
Solution Approach 2:
Physical respiratory monitoring devices (cameras, pressure belts, thermometers, point sources, pneumatic sensors) are replaced with computational algorithms that process image data to derive respiratory phase information. This substitution eliminates hardware costs while maintaining the ability to characterize respiratory motion reliably.
3Ease of manufacture
If automated image-based gating algorithms are implemented, then no additional hardware is needed and procedures remain routine, but processing time increases
Solution Approach 1:
The gating algorithms process and analyze image data in parallel with the acquisition process, performing preliminary characterization of respiratory motion during the scan rather than requiring post-processing. This allows the system to prepare gating signals and corrected images concurrently with data collection, minimizing total time loss.
Data Source
AI summary
The present invention, in one form, is a method for deriving respiratory gated PET image reconstruction from raw PET data. In reconstructing the respiratory gated images in accordance with the present invention, respiratory motion information derived from individual voxel signal fluctuations, is used in combination to create usable respiratory phase information. Employing this method allows the respiratory gated PET images to be reconstructed from PET data without the use of external hardware, and in a fully automated manner.