Reverse Geometry X-Ray Imager with Air Septa
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Solution Overview
Problem
Current x-ray imagers face challenges in achieving high frequency-dependent detective quantum efficiency (DQE(f)) and are costly to manufacture, particularly due to the need for pixelated scintillator geometries that suffer from high manufacturing costs and loss of fill factor, which complicates the incorporation into large-area imagers.
Innovation Solution
The implementation of a reverse geometry imaging device with air septa separating scintillator elements and a non-pixelated scintillator layer, combined with an optical grid, reduces optical crosstalk and enhances spatial resolution while minimizing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pixelated scintillator geometries with reflective septa are used to minimize optical blurring and achieve high spatial resolution, then spatial resolution is improved, but manufacturing cost increases significantly and fill factor is reduced
Solution Approach 1:
The patent extracts and removes the reflective septa from the scintillator array, eliminating the complex and costly process of cutting scintillators into parallelepipeds and gluing reflective septa between them. Instead, it uses a continuous scintillator layer coupled directly to the photodiode array, thereby reducing manufacturing cost while maintaining spatial resolution through optimized optical coupling
Solution Approach 2:
The patent merges the scintillator material into a continuous layer without segmentation, eliminating the need for separate reflective septa components. This integration simplifies the manufacturing process by removing multiple steps (cutting, gluing, assembling) while maintaining the optical isolation function through the inherent properties of the scintillator-photodiode interface
2Manufacturing precision
If pixelated geometries with reflective septa are used to confine optical photons, then spatial resolution is improved, but fill factor is reduced due to finite thickness of septa
Solution Approach 1:
The patent removes the reflective septa entirely from the system, eliminating the space they occupy and thereby maximizing the fill factor. The continuous scintillator layer allows more of the detector area to be active scintillating material, improving quantum efficiency while spatial resolution is maintained through direct optical coupling to the photodiode array
3Reliability
If thick pixilated scintillator arrays are used to improve DQE, then detective quantum efficiency is improved, but manufacturing cost increases due to complex cutting and assembly processes
Solution Approach 1:
The patent combines the scintillator material into a continuous thick layer that couples directly to the photodiode array, eliminating the need for pixelation and reflective septa. This approach maintains the dose collection efficiency of thick scintillators while dramatically simplifying manufacturing by removing the complex cutting and assembly processes required for pixilated arrays
Solution Approach 2:
The patent extracts and eliminates the pixilation structure and reflective septa, retaining only the essential function of the thick scintillator for dose collection. This reduces manufacturing complexity while preserving the high DQE achieved through increased scintillator thickness
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 significantly improves DQE(f) and spatial resolution by ensuring more optical photons reach the photodiode elements, reducing Swank noise, and lowering production expenses, making it more practical for large-area imaging applications.
Implementation Method 1
Incoming x-ray photons deposit energy into the scintillators which then produce optical photons via luminescence
Implementation Method 2
These optical photons, which originate with random polarizations and direction vectors after the luminescence events, are transported throughout the scintillator during which time they can be reflected, refracted and scattered. Eventually, many photons will cross the boundary between the scintillator and the EPID to be absorbed by the EPID's photodiodes and converted into electrical current for readout and digitization
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
An imaging device includes: a scintillator layer; and an array of photodiode elements; wherein the scintillator layer is configured to receive radiation that has passed through the array of photodiode elements. An imaging device includes: a scintillator layer having a plurality of scintillator elements configured to convert radiation into photons; and an array of photodiode elements configured to receive photons from the scintillator layer, and generate electrical signals in response to the received photons; wherein at least two of the scintillator elements are separated by an air gap. An imaging device includes: a first scintillator layer having a plurality of scintillator elements arranged in a first plane; and a second scintillator layer having a plurality of scintillator elements arranged in a second plane; wherein the first scintillator layer and the second scintillator layer are arranged next to each other and form a non-zero angle relative to each other.