Nested Collimator Assembly for CZT Detector Sensitivity
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Solution Overview
Problem
Conventional Nuclear Medicine (NM) imaging systems using Cadmium Zinc Telluride (CZT) detectors face limitations in sensitivity due to the absorption of radiation in stacked detector layers, resulting in inefficient use of detector area and reduced sensitivity when additional layers are added.
Innovation Solution
The implementation of a collimator assembly comprising a parallel-hole collimator and a pin-hole collimator, where the pin-hole collimator is positioned within the central opening of the parallel-hole collimator, allowing direct access of radiation to multiple CZT detector layers, thereby increasing sensitivity by allowing radiation to pass through without being absorbed by the first layer, and positioning the second layer at a distance to enhance sensitivity without compromising rotational range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thicker detectors or detectors arranged in stacked layers are used to improve sensitivity, then the sensitivity is improved, but the radiation from additional layers is absorbed by preceding layers, reducing the effectiveness of added detector area
Solution Approach 1:
The patent positions a pinhole collimator within the central opening of a parallel-hole collimator, creating a nested configuration where one collimator system is placed inside another. This nested arrangement allows the pinhole collimator to access radiation that would otherwise be blocked by the parallel-hole collimator structure, enabling multiple detector layers to receive radiation without complete absorption by preceding layers.
Solution Approach 2:
The patent transitions from a single-plane collimator arrangement to a three-dimensional nested collimator configuration. By placing the pinhole collimator in the central opening of the parallel-hole collimator, the system utilizes the third dimension (depth/layering) to create multiple radiation reception paths, allowing detectors at different depths to capture radiation from different angular perspectives.
2Area of stationary object
If multiple detector layers are stacked to increase detector area, then the detector area is increased, but the sensitivity does not improve proportionally due to radiation absorption in lower layers
Solution Approach 1:
The nested collimator configuration allows multiple detector layers to be positioned at different depths while maintaining effective radiation reception. The pinhole collimator nested within the parallel-hole collimator creates independent radiation pathways that bypass the absorption problem, enabling each detector layer to contribute proportionally to the overall sensitivity based on its active area.
3Length of moving object
If the second detector layer is positioned closer to the first layer, then the compactness is improved, but the rotational range and sensitivity enhancement are compromised
Solution Approach 1:
The patent resolves the conflict between compactness and rotational range by utilizing the third dimension (vertical stacking with nested collimators) rather than increasing horizontal separation. The nested collimator configuration allows detector layers to be positioned in close proximity vertically while the pinhole collimator's central positioning maintains adequate rotational arc clearance, achieving compact design without sacrificing rotational capability.
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 configuration increases the sensitivity of the detector system by up to 150% compared to single CZT layer systems, reduces radiation dose to patients, and decreases scan time, improving imaging efficiency and patient comfort.
Implementation Method 1
The parallel-hole collimator includes plural walls defining parallel holes therebetween... The at least one pin-hole collimator is positioned to collimate radiation received by at least one of the NM imaging detectors
Implementation Method 2
The plural nuclear medicine (NM) imaging detectors are configured to receive radiation from the source
Data Source
AI summary
A collimator assembly is provided including a parallel-hole collimator and a pin-hole collimator. The parallel-hole collimator includes plural walls defining parallel holes therebetween, with the parallel holes arranged around a central opening. The pin-hole collimator includes a pin-hole formed in a body, with the pin-hole collimator disposed within the central opening.