Helical Scanning PET Scanner with List-Mode Reconstruction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current PET scanners face limitations in spatial resolution due to the cylindrical geometry and high cost of small crystals, which affect the sensitivity and accuracy of image reconstruction, especially in clinical systems where sub-millimeter crystals are used.
Innovation Solution
A PET scanner system that includes a detector moving during acquisition, a patient bed moving along an arbitrary trajectory, and a list-mode reconstructing unit processing event information with time stamps, allowing for improved sampling density and spatial resolution without increasing hardware costs by sparsely disposing detector modules and using motion to fill sampling gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If small crystals are used to improve spatial resolution, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies dynamics by making the detector system movable relative to the patient bed, enabling the detector to traverse along the longitudinal axis. This motion allows a smaller number of detector modules to achieve comprehensive sampling coverage that would otherwise require densely packed stationary detectors, thereby reducing device complexity while maintaining spatial resolution
Solution Approach 2:
The patent introduces motion along the longitudinal axis as an additional dimension to the traditional transaxial detection geometry. By adding this temporal-spatial dimension through helical scanning, the system achieves sub-crystal resolution without requiring proportionally smaller crystals throughout the entire detector ring, thus avoiding the exponential cost increase associated with miniaturization
2Device complexity
If detector modules are sparsely disposed to reduce cost, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The movable detector system compensates for sparse module distribution by dynamically changing detection positions along the longitudinal axis. As the detector traverses through different z-positions, each sparse module samples different spatial locations, effectively filling sampling gaps that would exist in a static sparse configuration and maintaining measurement precision
Solution Approach 2:
The system performs preliminary sampling at multiple longitudinal positions before final image reconstruction. By collecting data at various z-positions during detector traversal, the system pre-fills the sampling matrix with sufficient information density, allowing accurate reconstruction even though individual detector modules are sparsely distributed
3Productivity
If cylindrical geometry is used to improve sensitivity, then productivity is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent combines cylindrical geometry with longitudinal motion, transforming the static circular detection path into a helical trajectory. This dynamic approach maintains the sensitivity advantages of cylindrical geometry while using motion to achieve the spatial resolution improvements that would otherwise require more complex multi-ring or non-cylindrical configurations
Data Source
AI summary
A positron emission tomography (PET) scanner system, including a detector that acquires PET event information, the detector being configured to move during acquisition of the PET event information; a first motion unit that acquires first event information of a position of a patient bed, the patient bed being configured to move during acquisition of the PET event information; a second motion unit that acquires second event information of the detector; an event collector that generates an event list of events that includes the PET event information, the first event information, and the second event information; and a list-mode reconstructing unit that reconstructs an image by processing the generated event list.