Virtual Sub-Pixel Detector Assembly for Nuclear Medicine Imaging
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Solution Overview
Problem
In Nuclear Medicine imaging, the size of detector units limits the proximity of detectors to the object being imaged, affecting sensitivity, resolution, and contrast due to manufacturing complexities and voltage breakdown constraints.
Innovation Solution
The use of virtual sub-pixel based sensing in conjunction with reduced collimator septa height, allowing for smaller detector unit sizes and improved detector placement, is achieved by employing a semiconductor detector with pixelated anodes and a collimator with specific septa length to pitch ratios, enabling closer object proximity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detector unit size is reduced to enable closer placement to the object, then sensitivity and resolution improve, but manufacturing complexity increases and voltage breakdown constraints are violated
Solution Approach 1:
The detector unit is segmented into multiple detector elements arranged in a grid pattern, with each element having its own readout circuitry. This segmentation allows for reduced overall detector unit size while maintaining manufacturing feasibility and electrical performance, as each segment can be independently fabricated and tested.
Solution Approach 2:
The invention transitions from planar pixel electrodes to three-dimensional columnar electrode structures extending through the thickness of the detector. This dimensional change allows for reduced in-plane detector unit size while maintaining sufficient electrical isolation and signal collection capability, thereby improving sensitivity and resolution without violating voltage breakdown constraints.
2Length of moving object
If detector unit size is reduced, then detector placement proximity to object improves, but manufacturing precision requirements increase
Solution Approach 1:
The detector is divided into multiple discrete detector elements with standardized dimensions, allowing for modular manufacturing. This segmentation enables reduced overall detector unit size while maintaining consistent fabrication tolerances across all elements, thereby improving placement proximity without excessively increasing manufacturing precision requirements.
Solution Approach 2:
The invention changes the electrode geometry from two-dimensional pixels to three-dimensional columns extending through the detector thickness. This parameter change allows for reduced in-plane detector unit dimensions while maintaining adequate electrical isolation and signal collection, thereby enabling closer object placement without proportionally increasing manufacturing precision demands.
3Volume of moving object
If collimator septa height is reduced, then detector unit size decreases, but sensitivity may be compromised
Solution Approach 1:
The detector is segmented into multiple small detector elements with dedicated readout circuits, increasing the effective sampling density. This segmentation compensates for the reduced collimator septa height by providing more detection channels, thereby maintaining sensitivity while reducing overall detector unit volume.
Solution Approach 2:
The electrode structures extend in the third dimension (through the detector thickness) rather than only in the plane parallel to the collimator. This dimensional change allows for reduced in-plane detector unit size and reduced collimator septa height while maintaining adequate signal collection efficiency, thereby reducing detector unit volume without compromising sensitivity.
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 image quality by increasing sensitivity, resolution, and contrast while reducing detector unit size, allowing for closer placement to the object being imaged without compromising sensitivity or resolution.
Implementation Method 1
The semiconductor detector has a first surface and a second surface opposed to each other. The first surface includes pixelated anodes, and the second surface includes a cathode electrode.
Data Source
AI summary
A detector assembly is provided that includes a semiconductor detector, a collimator, and a processing unit. The semiconductor detector has a first surface and a second surface opposed to each other. The first surface includes pixelated anodes, and the second surface includes a cathode electrode. The collimator includes openings defined by septa. The collimator defines a pitch D between adjacent septa, with the septa defining a septa length L. A ratio of L/D is less than 14. The processing unit is configured to identify detected events within virtual sub-pixels distributed along a length and width of the semiconductor detector. Each pixel comprises a plurality of corresponding virtual sub-pixels, and absorbed photons are counted as events in a corresponding virtual sub-pixel.