PET Patient Positioning for AFOV Edge Sensitivity Loss
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Solution Overview
Problem
Existing PET imaging systems with large axial field of view (AFOV) suffer from reduced sensitivity at the edges, leading to suboptimal imaging quality when scanning regions of interest that are larger than the AFOV or positioned off-center.
Innovation Solution
A computer-implemented method and system that generates an anatomical reference image with a sensitivity ruler, adjusts the patient position to center the region of interest within the AFOV, and acquires emission tomography scan data to maximize detection sensitivity, resulting in higher image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the axial field of view (AFOV) of PET scanners is increased to image larger sections of the patient, then the coverage area is improved, but the sensitivity at the edges of the AFOV decreases
Solution Approach 1:
The system applies different quality characteristics to different regions of the AFOV by using variable pitch spiral scanning. The scanning parameters are locally optimized: regions with higher sensitivity receive different scanning treatment than regions with lower sensitivity, ensuring optimal image quality throughout the entire AFOV while maintaining high sensitivity in all areas
2Measurement precision
If the axial field of view (AFOV) is increased to high sensitivity, then the detection capability is improved, but the sensitivity becomes non-uniform with maximal sensitivity only in the middle
Solution Approach 1:
The system employs dynamic scanning parameters including variable pitch spiral scanning where the pitch and rotation speed are continuously adjusted during the scan. This dynamic approach allows the system to compensate for the non-uniform sensitivity profile, maintaining consistent detection capability across the entire AFOV by adapting the scanning trajectory to the detector response characteristics
Data Source
AI summary
An example imaging system includes a detector array arranged in multiple rings defining an axial field of view (AFOV), a patient table configured to translate a subject along the AFOV, wherein the detector array includes one or more detector modules to acquire emission tomography scan data at a first bed position and at a second bed position, and one or more processors to combine scan data from overlapping scan ranges of the first and second bed positions to generate a combined sensitivity profile across a desired scan range and to reconstruct a diagnostic image using the combined data, wherein the combined sensitivity profile exhibits increased sensitivity in a central section of the overlap relative to sensitivity obtained from a single bed position.