PET Detector Efficiency Normalization via Spatial High-Pass Filtering
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Solution Overview
Problem
Existing PET detector normalization methods are inherently affected by geometric factors and require complex calculations or extensive scan times, making them inefficient and time-consuming.
Innovation Solution
A method that uses singles emission data and applies a spatial high-pass filter to determine relative detector element efficiencies in a PET-scanning device, reducing the impact of geometric factors and shortening acquisition time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional normalization methods (direct normalization or component-based normalization) are used, then detector efficiency can be normalized, but the process is time-consuming and requires complex calculations and extensive scan times
Solution Approach 1:
The patent extracts only the essential information needed for normalization from the complete PET scan data. By using singles emission data and applying a spatial high-pass filter, the method isolates the geometric factor information from the complex coincidence data, enabling fast normalization without requiring extensive scan times or complex calculations of all geometric parameters
Solution Approach 2:
The patent replaces the traditional mechanical/physical normalization process (requiring phantom scans and complex geometric calculations) with a data-processing approach. By substituting the physical normalization measurement with a computational method using high-pass filtering on singles data, the system achieves normalization accuracy without the time-consuming physical measurements
2Measurement precision
If traditional normalization methods are used, then detector efficiency can be normalized, but geometric factors adversely affect the determination of normalization coefficients
Solution Approach 1:
The patent converts the harmful effect of geometric factors into a beneficial signal. By applying a spatial high-pass filter to the singles emission data, the method enhances the geometric factor information that was previously considered noise or interference. This filtered geometric information is then used to calculate accurate normalization coefficients, transforming the geometric factors from a harmful influence into a useful normalization parameter
Solution Approach 2:
The patent applies local quality by treating different spatial regions of the detector differently. The spatial high-pass filter processes the singles emission data to highlight local variations in detector response that are specific to each detector element's geometric relationship with the source. This allows individual detector elements to be normalized based on their specific geometric characteristics rather than using a uniform normalization approach
3Measurement precision
If coincidence data is used for normalization, then detector efficiency can be determined, but the acquisition time is extended and calculations become more complex
Solution Approach 1:
The patent extracts the normalization information from the simpler singles emission data rather than from complex coincidence data. By taking out the essential geometric factor information from the singles channel and processing it through a high-pass filter, the method achieves detector efficiency determination without requiring the complex coincidence measurements and calculations
Solution Approach 2:
The patent segments the normalization process into distinct steps: acquiring singles emission data, applying spatial high-pass filtering to extract geometric factors, and calculating normalization coefficients. This segmentation separates the normalization task from the complex coincidence processing, making the overall system simpler and faster while maintaining accuracy
Data Source
AI summary
A method for determining relative detector element efficiencies in a positron emission tomography (PET)-scanning device is indicated. The method includes the steps of: a) acquiring a histogram of singles emission data by a detector of the PET-scanning device, wherein each bin of the histogram is associated to one of a plurality of detector elements of the detector and reflects the sum of singles emissions detected by the respective detector element during a certain period of time; and b) applying a spatial high-pass filter to the acquired histogram of singles emission data. Furthermore, a PET-scanning device configured to carry out this method and a computer program for controlling such a PET-scanning device are provided.