Adjustable Focal Length Collimators for SPECT Imaging
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Solution Overview
Problem
Conventional SPECT imaging systems have fixed focal lengths in their collimator assemblies, which limits the ability to adjust system resolution and sensitivity without replacing the entire collimator, particularly challenging when imaging subjects with varying anatomy like the heart, which is often eccentrically positioned.
Innovation Solution
The implementation of a SPECT imaging system with pinhole-detector modules that allow for adjustable focal lengths between the pinhole apertures and detector assemblies, enabling dynamic adjustment of system resolution and sensitivity without the need for collimator exchange, using mechanisms like collapsible assemblies to modify the focal length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed focal length collimator assembly is used, then the system structure is simple and stable, but the ability to adjust system resolution and sensitivity is limited
Solution Approach 1:
The patent applies the dynamics principle by making the focal length adjustable rather than fixed. The collimator assembly includes a mechanism that allows the distance between the pinhole aperture and detector assembly to be dynamically changed, enabling adaptation to different imaging requirements without replacing the entire collimator. This resolves the contradiction by introducing adjustability while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent changes the focal length parameter to adjust system resolution and sensitivity. By varying the distance between the pinhole aperture and detector assembly, the system can optimize its performance for different imaging scenarios. This parameter change approach allows the same physical collimator to serve multiple purposes, improving adaptability without requiring multiple different collimator assemblies.
2Measurement precision
If the focal length is adjusted to image eccentric structures like the heart, then imaging accuracy improves, but the collimator assembly must be replaced
Solution Approach 1:
The patent enables dynamic adjustment of the focal length within the same collimator assembly, eliminating the need to replace the collimator when imaging eccentric structures. The adjustable mechanism allows rapid reconfiguration of the imaging geometry to match the patient's anatomy, saving time and maintaining imaging accuracy.
Solution Approach 2:
The system allows preliminary adjustment of the focal length to match the expected anatomy before actual imaging begins. This preliminary configuration ensures that the collimator is already optimized for the specific imaging task, avoiding the need for time-consuming replacements during the imaging process.
3Area of stationary object
If multiple pinhole apertures are used to image different regions, then coverage is improved, but the distance from each pinhole to the source varies causing inconsistent magnification
Solution Approach 1:
The patent applies dynamics by allowing individual adjustment of the focal length for each pinhole aperture or for different regions of the collimator assembly. This enables compensation for varying distances from each pinhole to the source, ensuring consistent magnification across all apertures while maintaining broad coverage.
Solution Approach 2:
The patent implements local quality by allowing different focal lengths for different pinhole apertures or regions. Each aperture can be independently optimized based on its specific distance to the source, ensuring uniform image magnification and quality across the entire field of view while maintaining the benefits of multi-aperture coverage.
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 allows for consistent image magnification or minification across all pinhole apertures, maximizing detector area usage and maintaining sensitivity while adjusting image resolution, facilitating high-resolution imaging of eccentric structures like the heart without the need for collimator replacement.
Implementation Method 1
the collimator assembly is designed to absorb photons such that only photons traveling in certain directions impact the detector assembly
Implementation Method 2
the detector assembly may utilize a scintillator assembly (e.g., large sodium iodide scintillator plates) to convert the photons into visible light
Implementation Method 3
multiple photomultiplier tubes (PMTs) or other light sensors that convert the light from the scintillator assembly into an electric signal
Data Source
AI summary
Embodiments relate to an imaging system that includes a collimator assembly having one or more pinhole apertures therein. The imaging system is configured so that one or more of the pinhole apertures has an adjustable focal length. The imaging system further includes a detector assembly configured to generate one or more signals in response to gamma rays that pass through the one or more pinhole apertures. Embodiments also relate to methods of changing collimator performance and methods of imaging a volume.