Multilayer Scintillation Crystal for PET Detector Spatial Resolution

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Solution Overview

Problem

Conventional PET detectors using single-layer scintillation crystals face limitations in spatial resolution and efficiency due to the diffusion of scintillating light, requiring extensive reference data for accurate energy deposition position calculation, making them unsuitable for mass production or clinical applications.

Innovation Solution

A multilayer scintillation crystal structure is introduced, comprising continuous scintillation crystals coupled between a photoelectric detector and a scintillation crystal array, optimizing the thickness of continuous scintillation crystals to enhance energy deposition information acquisition, with a coupler such as optical glue or a light guide between layers for improved light diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single-layer continuous scintillation crystal is used, then the spatial resolution can be improved through light diffusion, but extensive reference data is required for accurate energy deposition position calculation, making mass production and clinical application difficult

Engineering Contradiction:
Improvespatial resolutionVSAvoidreference data acquisition complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the single-layer continuous scintillation crystal into multiple layers with different structures (strip-type crystals in some layers, continuous crystal in others). This segmentation allows the system to achieve spatial resolution through structural design rather than requiring extensive reference data, resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different crystal structures to different layers: strip-type scintillation crystals in certain layers provide direct position encoding, while continuous crystals in other layers provide light diffusion. This local quality differentiation enables accurate energy deposition position calculation without requiring extensive reference data, solving the contradiction between spatial resolution and system complexity.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If strip-type scintillation crystals are made smaller to improve spatial resolution, then more precise position information is obtained, but scintillating light from multiple crystals is received by the same SiPM, preventing energy deposition position distinction

Engineering Contradiction:
Improvespatial resolutionVSAvoidenergy deposition position information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces a vertical dimension by stacking multiple layers of scintillation crystals with different structures. This multi-layer configuration allows the system to resolve energy deposition positions in three dimensions, preventing information loss that occurs when small strip crystals cause light diffusion to adjacent detectors in a single layer.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

By segmenting the detector into multiple layers with alternating strip-type and continuous crystal structures, the patent ensures that scintillating light from small strip crystals is captured by dedicated SiPMs in the same layer, while adjacent layers provide additional position encoding information. This segmentation prevents the information loss that would occur in a single-layer design.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If a multilayer scintillation crystal is used to acquire DOI information and improve spatial resolution, then more energy deposition information is obtained, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvespatial resolutionVSAvoidmanufacturing ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges different crystal structures (strip-type and continuous) into a unified multilayer configuration that achieves both DOI information acquisition and improved spatial resolution. By combining these structures in specific patterns, the system maintains manufacturing feasibility while achieving high measurement precision, resolving the contradiction between performance and ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent optimizes parameters such as crystal layer thickness, strip dimensions, and material composition to balance performance requirements with manufacturing capabilities. By carefully selecting and adjusting these parameters, the system achieves high spatial resolution and DOI information acquisition while maintaining reasonable ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

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

The multilayer scintillation crystal design allows for more accurate and efficient acquisition of energy deposition information of γ photons, enabling higher spatial resolution and detection efficiency, facilitating the use of corresponding algorithms for precise energy and time information extraction.

Implementation Method 1

A PET detector, as a key component of a PET device, mainly functions to acquire position, time and energy information of energy deposition for each γ photon

Methodology Applied
Scientific EffectScintillation: Scintillation

Implementation Method 2

with a coupler such as optical glue or a light guide between layers for improved light diffusion

Methodology Applied
Scientific EffectLight diffusion: Diffusion

Data Source

PatentEP2866057B1Multilayer scintillation crystal and pet detector
Publication Date: 2020.11.18 RAYCAN TECH CO LTD SU ZHOU
  • EP2866057B1 patent drawingFigure 1~2
  • EP2866057B1 patent drawingFigure 3~4
  • EP2866057B1 patent drawingFigure 5~6

AI summary

A multilayer scintillation crystal (1) comprises n layers of array scintillation crystals and m layers of continuous scintillation crystals which have uncut inner parts, both n and m being integers greater than or equal to 1 and a sum of n and m being smaller than or equal to 10. The array scintillation crystals are formed by strip-type scintillation crystals arranged along the width and length directions, the array scintillation crystals and the continuous scintillation crystals are sequentially coupled along the height direction of the strip-type scintillation crystals to form the multilayer scintillation crystal (1), and the continuous scintillation crystals are located at the bottom of the multilayer scintillation crystal (1). The adding of the continuous scintillation crystals between the array scintillation crystals and a photoelectric detector system (2) facilitates photon diffusion of a scintillating light, and through optimization design of the thickness of the continuous scintillation crystals, the distribution of the scintillating light received by the photoelectric detector carries more abundant energy deposition information. More accurate energy deposition information of γ photons in the scintillation crystal can be obtained through full utilization of the abundant energy deposition information by using a corresponding information extraction algorithm.