PET Image Correction with Partial CT-Derived Attenuation Maps
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Solution Overview
Problem
Existing PET/CT imaging systems require high radiation doses for whole-body scans due to the need for attenuation correction, which is typically achieved through transmission scans using CT scanners.
Innovation Solution
A method and system for attenuation correction that utilizes PET and CT image data to determine relationships and generate an attenuation map, allowing for reduced radiation exposure by segmenting tissue types and applying specific attenuation coefficients to correct PET images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a whole body of the subject is scanned using the CT scanner for attenuation correction, then the attenuation map accuracy is improved, but the radiation dose to the subject increases
Solution Approach 1:
The patent segments the body into multiple regions (e.g., head, thorax, abdomen, pelvis) and performs CT scanning only on selected regions rather than the entire body. The attenuation map is then constructed by combining region-specific CT data with estimated attenuation values for other regions, thereby reducing radiation exposure while maintaining sufficient attenuation correction accuracy.
Solution Approach 2:
The patent applies different attenuation correction strategies to different body regions. High-precision CT-based attenuation correction is applied only to regions where it is most needed (e.g., regions with high tracer uptake or complex anatomy), while other regions use simplified attenuation estimation methods, optimizing the balance between accuracy and radiation dose.
2Object-affected harmful factors
If a partial body of the subject is scanned using the CT scanner, then the radiation dose is reduced, but the attenuation map accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary process that estimates attenuation coefficients for regions not directly scanned by CT. This estimation uses available PET data, anatomical priors, and physiological models to generate plausible attenuation values for unscanned regions, allowing the construction of a complete attenuation map from partial CT data.
Solution Approach 2:
The patent makes the PET data serve multiple functions: it provides both the functional imaging information and serves as a source of attenuation information for regions where CT data is unavailable. By extracting attenuation coefficients from PET data through calibration and transformation, the system compensates for the lack of direct CT measurements in unscanned regions.
Data Source
AI summary
The disclosure relates to a system and method for correcting PET image data. PET image data of a first part of a subject may be obtained. CT image data of a second part of the subject may be obtained. The first part may include the second part. PET voxel data of the first part may be obtained based on the PET image data of the first part. A relationship between the CT image data and PET voxel data of the second part may be determined. CT image data of a third part of the subject may be determined based on the relationship and PET voxel data of the third part. The first part may include the third part. An attenuation map may be determined based on the CT image data of the second part and the third part. The PET image data of the first part may be corrected based on the attenuation map.