Overlapping Pixel Summing for Photon Counting CT Detectors
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Solution Overview
Problem
Photon counting computed tomography (CT) systems face challenges in material decomposition accuracy due to pileup effects, charge sharing, and sensor material non-uniformity, leading to degraded image quality and spatial resolution.
Innovation Solution
A dynamically configurable photon counting detector (PCD) array with overlapping micro-pixel summing, where signals from first and second groups of micro-pixels overlap, allowing for binning into virtual bin values, improving spatial resolution and noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to improve spatial resolution, then spatial resolution is improved, but charge sharing effects increase and signal-to-noise ratio decreases
Solution Approach 1:
The patent merges multiple micro-pixels into macro-pixels through overlapping summing schemes. By combining signals from multiple micro-pixels (e.g., 2x2, 2x3, or 3x3 blocks), the system achieves larger effective pixel sizes that improve signal-to-noise ratio while maintaining spatial resolution through the overlapping configuration that preserves edge information.
Solution Approach 2:
The patent implements dynamically configurable pixel summing where the degree of overlap between macro-pixels can be adjusted. This dynamic configuration allows the system to adapt the summing scheme based on imaging conditions, optimizing the balance between spatial resolution and signal-to-noise ratio for different clinical applications.
2Reliability
If pixel size is increased to reduce charge sharing effects, then signal-to-noise ratio is improved, but spatial resolution deteriorates
Solution Approach 1:
The patent segments the detector array into multiple micro-pixels that are then grouped into macro-pixels through overlapping summing. This segmentation allows the system to maintain the spatial resolution benefits of fine pixel structure while achieving the signal-to-noise ratio benefits of larger effective pixel sizes through the controlled overlapping configuration.
Solution Approach 2:
The patent merges multiple micro-pixels into macro-pixels with controlled overlap. This merging strategy enables the system to achieve larger effective pixel sizes for improved signal-to-noise ratio while the overlapping structure preserves spatial resolution by maintaining relationships between adjacent macro-pixels.
3Reliability
If pixel summing size is increased to reduce noise, then signal-to-noise ratio is improved, but spatial resolution deteriorates
Solution Approach 1:
The patent applies different summing configurations to different regions of the detector array. By varying the overlap parameters and summing schemes locally, the system can optimize the balance between signal-to-noise ratio and spatial resolution for different imaging conditions and anatomical regions, rather than using a uniform summing approach throughout.
Solution Approach 2:
The patent implements dynamically adjustable pixel summing where the degree of overlap and the specific summing configuration can be changed based on imaging requirements. This dynamic adaptation allows the system to use larger summing sizes for low-noise requirements in certain regions while maintaining smaller summing sizes for high spatial resolution requirements in other regions.
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
The overlapping pixel summing method enhances image quality by reducing noise and improving spatial resolution, mitigating the effects of pileup and sensor material non-uniformity, while maintaining robust projection measurements.
Implementation Method 1
semiconductor-based detector using direct conversion is designed to resolve the energy of the individual incoming photons
Implementation Method 2
spectral CT generates information due to different materials exhibiting different X-ray attenuation as a function of the X-ray energy
Data Source
AI summary
A photon counting detector (PCD) apparatus includes a PCD array including a plurality of micro-pixels positioned in at least one of a channel direction and a row direction; and processing circuitry configured to: receive signals from each of the plurality of micro-pixels; configure the PCD array to include (a) a first micro-pixel area including a first group of plural micro-pixels of the plurality of micro-pixels and (b) a second micro-pixel area including a second group of plural micro-pixels of the plurality of micro-pixels, such that a portion of the first and second groups of plural micro-pixels overlap between the first and second groups; bin the signals from the first group of plural micro-pixels into a first virtual bin value; and bin the signals from the second group of plural micro-pixels into a second virtual bin value.