PET Attenuation Correction Using OSEM-B and FBP Weighted Reconstruction
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Solution Overview
Problem
Current attenuation correction methods in PET systems require lengthy transmission scanning, leading to inefficient image processing and increased patient discomfort, as they struggle to balance accuracy and time efficiency.
Innovation Solution
The method employs a Bayesian model-based Ordered Subset Expectation Maximization (OSEM-B) algorithm in conjunction with Filtered Back Projection (FBP) to reconstruct transmission scanning sinogram data, followed by a weighted calculation to generate an effective attenuation image, which is then used for attenuation correction in emission scanning, significantly reducing transmission scanning time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional transmission scanning is used to generate attenuation sinogram, then attenuation correction precision is improved, but scanning time increases significantly
Solution Approach 1:
The patent segments the attenuation correction process into two parts: (1) use a rapid low-dose transmission scan to obtain initial attenuation map, and (2) use the pre-acquired patient-specific attenuation map to correct the emission scan. This segmentation allows the time-consuming high-precision transmission scan to be replaced by a rapid scan combined with algorithmic processing, thereby reducing total scanning time while maintaining correction precision.
Solution Approach 2:
The patent performs preliminary attenuation correction using the rapid transmission scan data before final image reconstruction. By pre-calculating the attenuation map from the quick scan and applying it to correct the emission data, the system avoids the need for prolonged transmission scanning, thus resolving the contradiction between precision and time efficiency.
2Productivity
If transmission scanning time is reduced to improve efficiency, then patient comfort and throughput are improved, but attenuation correction accuracy deteriorates
Solution Approach 1:
The patent changes the scanning parameters by using a rapid low-dose transmission scan instead of the traditional long-duration high-dose scan. By adjusting the scan duration and dose parameters, the system achieves sufficient attenuation map quality for correction purposes without the time and dose burden of conventional scanning, thus improving productivity while maintaining acceptable accuracy.
Solution Approach 2:
The patent introduces an intermediary step where the rapid transmission scan data is processed to generate an attenuation map, which then serves as a mediator to correct the emission scan. This intermediary approach allows the system to use minimal transmission scan data effectively, bridging the gap between rapid scanning and accurate correction.
3Measurement precision
If segmented attenuation correction with multiple regions is used, then correction accuracy is improved, but processing complexity and time increase
Solution Approach 1:
The patent applies local quality by assigning different attenuation coefficients to different anatomical regions (soft tissue, lung, bone, air) based on the rapid transmission scan data. By detecting tissue types locally and applying region-specific correction factors, the system achieves accurate correction without requiring complex multi-step processing, thus balancing precision and simplicity.
Data Source
AI summary
An attenuation correction method and device for an image in a PET system. The method includes: acquiring transmission scanning sinogram data from a PET apparatus; reconstructing the transmission scanning sinogram data with Bayesian model-based Ordered Subset Expectation Maximization (OSEM-B) algorithm and Filtered Back Projection (FBP) algorithm, to obtain an OSEM-B attenuation image and a first FBP attenuation image respectively; performing a weighted calculation on the OSEM-B attenuation image and the first FBP attenuation image to obtain an effective attenuation image; and performing attenuation correction on emission scanning sinogram data from the PET apparatus by using an attenuation sinogram generated based on the effective attenuation image.