Scintillation Crystal DOI Decoding via Light-Transmitting Windows
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Solution Overview
Problem
Existing emission tomography devices face challenges in accurately determining the Depth Of Interaction (DOI) of scintillation crystals, leading to decreased spatial resolution due to photon attenuation and deviation in γ photon position calculation, which current hardware and software calibration methods are unable to effectively address.
Innovation Solution
A detector for emission tomography devices is designed with a scintillation crystal array directly coupled to a photo sensor array, where light-transmitting windows are disposed on adjacent scintillation crystals to allow light to be received by adjacent photo sensors, enabling accurate DOI decoding without mutual interference and improving decoding capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If γ photons interact within scintillation crystals at non-central positions, then the interaction position can be detected, but the Depth Of Interaction effect causes deviation between simulated and actual generation positions, decreasing spatial resolution
Solution Approach 1:
The light-reflecting layer on each scintillation crystal is segmented by introducing light-transmitting windows at specific positions. This segmentation allows light to escape through designated paths to adjacent crystals, enabling the system to detect which crystals receive light and calculate DOI information based on the light distribution pattern across multiple crystals.
Solution Approach 2:
Adjacent scintillation crystals act as intermediaries in the light detection process. When light-transmitting windows are introduced, light from one crystal can be received by adjacent crystals through these windows, creating a mediator relationship that enables cross-validation and more accurate determination of the original interaction position and DOI.
2Measurement precision
If hardware calibration methods are used to reduce DOI effect, then spatial resolution may be improved, but system complexity and sensitivity are degraded due to increased channels or photon loss
Solution Approach 1:
The light-transmitting windows enable adjacent scintillation crystals to serve multiple functions: they continue to detect γ photons that interact within them while simultaneously acting as light receivers for adjacent crystals. This multi-functionality allows the system to obtain DOI information without increasing the number of photo sensors or readout channels, maintaining system simplicity while improving measurement precision.
3Loss of energy
If light-reflecting material is coated on all crystal surfaces, then light collection efficiency is improved, but DOI decoding capability is reduced due to mutual interference
Solution Approach 1:
Instead of uniformly coating all crystal surfaces with light-reflecting material, the invention applies light-reflecting material to most surfaces while leaving specific local areas (light-transmitting windows) uncovered. This local quality differentiation allows light to escape through designated paths to adjacent crystals, enabling DOI decoding while maintaining high light collection efficiency through the reflective coating on other surfaces.
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 enhances the accuracy of DOI decoding and spatial resolution by allowing multiple photo sensors to accurately determine the interaction position of γ photons, reducing the number of photo sensors and readout channels required, and improving decoding capability by up to nine times.
Implementation Method 1
The 511 keV high-energy photons (i.e., γ photons) generated by the annihilating effect interact within the crystal matrix 110 and are converted into a group of visible photons
Implementation Method 2
surfaces of the plurality of the scintillation crystals not coupled to the photo sensor array are each provided with a light-reflecting layer
Implementation Method 3
a light-transmitting window is disposed in the light-reflecting layer on a surface among the surfaces adjacent to a scintillation crystal coupled to an adjacent photo sensor
Implementation Method 4
a photo sensor array, coupled to an end surface of the scintillation crystal array and including multiple photo sensors
Data Source
AI summary
The present invention provides a detector and an emission tomography device including the detector. The detector comprises: a scintillation crystal array comprising a plurality of scintillation crystals; and a photo sensor array, coupled to an end surface of the scintillation crystal array and comprising multiple photo sensors. At least one of the multiple photo sensors is coupled to a plurality of the scintillation crystals respectively. Surfaces of the plurality of the scintillation crystals not coupled to the photo sensor array are each provided with a light-reflecting layer, and a light-transmitting window is disposed in the light-reflecting layer on a surface among the surfaces adjacent to a scintillation crystal coupled to an adjacent photo sensor. The detector has DOI decoding capability. No mutual interference occurs during DOI decoding, and decoding is more accurate. Moreover, with the number of photo sensor arrays being the same, the decoding capability for the scintillation crystals is significantly improved. With the number of photo sensor arrays being the same, the size of the photo sensor array and the number of channels of a readout circuit of the photo sensors of the present invention can be reduced by three-quarters to eight-ninths.