PET Detector DOI Accuracy via Optical Separators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional PET scanners experience a progressive reduction in spatial resolution with increased distance from the center of their field of view due to uncertainty in assigning lines of response (LOR) to detected coincident events, leading to non-uniform resolution across the field of view.
Innovation Solution
A PET detector system that includes a crystal array and a photon-sensor array optically coupled with the crystal array, utilizing optical separators to control light transmission and determine the position of photon gamma interactions based on output information from the photon-sensors, thereby improving the accuracy of depth of interaction (DOI) determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PET scanners use standard detector modules without DOI determination, then the device complexity is low, but the spatial resolution deteriorates with increased distance from the center of field of view
Solution Approach 1:
The patent introduces depth of interaction (DOI) measurement along the axial dimension of the crystal element. By determining the interaction depth position within the crystal (adding a depth dimension to the usual 2D detector surface coordinates), the system achieves more accurate LOR assignment and uniform spatial resolution throughout the field of view without requiring multiple detector layers or complex mechanical structures.
Solution Approach 2:
The patent employs light guide members as intermediary components that optically couple the distal end of the crystal element to the photon sensor. These light guides transmit and shape the scintillation light from the interaction region to the sensor, enabling DOI determination through light distribution patterns while maintaining a relatively simple overall detector structure compared to dual-ended readout systems.
2Measurement precision
If PET detectors determine DOI using multiple photon-sensors coupled to both ends of crystal elements, then the spatial resolution improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the DOI determination function from complex multi-sensor readout electronics and implements it through optical design alone. By using a single photon sensor with carefully designed light guide members, the system separates the DOI measurement function from the crystal element structure itself, achieving DOI capability through optical path design rather than requiring complex electronic readout assemblies for each crystal.
Solution Approach 2:
The light guide members serve multiple functions: they transmit scintillation light from the crystal to the photon sensor, shape the light distribution pattern to encode depth information, and provide mechanical coupling between components. This multi-functionality reduces the need for separate DOI determination mechanisms and simplifies the overall detector assembly process.
3Area of stationary object
If PET scanners use detector modules located far from the central axis, then the field of view coverage increases, but the LOR assignment uncertainty and resolution loss increase
Solution Approach 1:
The patent replaces mechanical/geometric constraints with optical information processing to improve LOR assignment accuracy. Instead of relying solely on the geometric relationship between detector modules (which deteriorates at larger radii), the system uses optical patterns from light guide members to encode depth information, enabling accurate LOR calculation independent of the detector's radial position from the scanner center.
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 imaging resolution by accurately assigning LORs to coincident events, providing more uniform resolution throughout the field of view without the need for additional complex detector electronics.
Implementation Method 1
a crystal element configured to receive a gamma photon and to convert the gamma photon to a group of optical photons
Implementation Method 2
an optical separator configured to control transmission of the optical photons from the first crystal element to the second crystal element
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The present disclosure relates to devices, systems and methods for determining a position of a photon gamma interaction in a PET detector. The PET detector may include a crystal array and a single-end read-out structure. The single-end read-out structure may include a photon-sensor array optically coupled with the crystal array. The crystal array may include a plurality of crystal elements arranged along a first direction and a second direction. The crystal elements may form a plurality of crystal groups along the first direction. The PET detector may further include a plurality of optical separators of the same or different lengths configured to control light transmission in the PET detector. The position of the photon gamma interaction in a crystal group may be determined based on output information of the photon-sensor array optically coupled with the crystal group.