SPECT Collimator Pinhole Segmentation for Artifact Reduction
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Solution Overview
Problem
Current SPECT imaging devices face challenges in achieving artifact-free imaging of bodily organs within delimited regions due to overlapping pinhole projections, which lead to inconsistent activity distribution and reduced reconstruction accuracy.
Innovation Solution
The implementation of a multi-region imaging scheme with non-overlapping and overlapping projections allows for the central field of view to be imaged with favorable characteristics, reducing artifacts and improving contrast-to-noise ratio (CNR) by focusing pinholes on specific regions within the detector, ensuring unambiguous imaging of the central field of view and reconstructing it artifact-free.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pinholes are applied in the collimator to increase sensitivity, then the sensitivity of imaging is significantly increased, but overlapping projections are generated that lead to artifacts and reduced reconstruction accuracy
Solution Approach 1:
The patent divides the imaging space into multiple distinct regions (first region, second region, third region) with different pinhole configurations. The first region uses non-overlapping pinhole projections for artifact-free imaging, while the second and third regions use overlapping pinhole projections for enhanced sensitivity, thereby segmenting the problem to resolve the contradiction between sensitivity and reconstruction accuracy.
Solution Approach 2:
Different regions of the imaging field are assigned different imaging characteristics: the first region (central field of view) uses non-overlapping projections for high reconstruction accuracy, while the second and third regions (peripheral fields) use overlapping projections for high sensitivity. This local differentiation allows each region to have optimized quality for its specific imaging needs.
2Area of stationary object
If overlapping pinhole projections are used to cover a larger field of view, then the field of view is expanded, but inconsistent activity distribution occurs leading to artifacts
Solution Approach 1:
The patent segments the field of view into multiple regions with different projection characteristics. The first region uses non-overlapping projections to eliminate artifacts, while the second and third regions use overlapping projections to expand the overall field of view. This segmentation allows the system to achieve both goals: expanded FOV and artifact-free imaging in critical regions.
Solution Approach 2:
The patent converts the harmful effect of overlapping projections (which cause artifacts) into a beneficial feature by strategically assigning overlapping projections only to peripheral regions (second and third regions) where they expand the field of view without compromising the quality of the central region imaging. The harm is localized and transformed into a benefit for peripheral imaging.
3Reliability
If non-overlapping pinhole projections are used to avoid artifacts, then reconstruction accuracy is improved, but the number of independent measurements is reduced
Solution Approach 1:
The patent segments the measurement strategy by region: the first region (central FOV) uses non-overlapping projections to ensure high reconstruction accuracy with sufficient independent measurements, while the second and third regions (peripheral FOV) use overlapping projections to generate additional independent measurements. This segmentation resolves the contradiction by applying different strategies where appropriate.
Solution Approach 2:
The patent merges multiple imaging regions with different projection characteristics into a single unified imaging system. The first, second, and third regions are combined in one collimator element, allowing the system to simultaneously achieve high reconstruction accuracy in the central region and enhanced measurement coverage in peripheral regions, thereby merging the benefits of both non-overlapping and overlapping projections.
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
This approach enhances the imaging characteristics of the central field of view, reducing artifacts and improving the accuracy and sensitivity of SPECT imaging, allowing for better diagnostic value, especially in cases like brain examinations where activity distribution is extensive.
Implementation Method 1
a collimator element being adapted for projecting the photon on the detector, having an inlet surface, an outlet surface facing the incidence surface, and comprising pinholes connecting the inlet surface and the outlet surface
Implementation Method 2
a detector being adapted for determining a point of incidence of a—typically gamma—photon
Data Source
AI summary
The invention is an imaging device comprising detector and collimator element (144) applied e.g. in a SPECT. In the imaging device according to the invention the collimator element comprises—one or more first pinholes (146a, 148a) being focussed on a central field of view (141), the one or more first pinholes (146a, 148a) being adapted for projecting the central field of view (141) on one or more respective first imaging regions (52) being non-overlapping with any other imaging regions;—one or more second pinholes (148b) being focussed on a central field of view (141), the one or more second pinholes (148b) being adapted for projecting the central field of view (141) on one or more respective second imaging regions (56);—one or more second pinholes (148c) being focussed on a primary field of view (142) comprising the central field of view (141), the one or more third pinholes (148c) being adapted for projecting the primary field of view (142) on one or more respective third imaging regions (58) overlapping with at least one second imaging region (56). The invention is furthermore a tomographic apparatus (e.g. a SPECT) comprising the imaging device. (FIG. 13).