PET Detector Virtual Segmentation for Higher TOF Resolution

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Solution Overview

Problem

Conventional PET apparatuses face limitations in spatial and temporal resolution due to the use of scintillator pieces, leading to theoretical constraints in image reconstruction, particularly in Time Of Flight (TOF) temporal resolution.

Innovation Solution

A PET apparatus utilizing a monolithic scintillator and processing circuitry to determine virtual detector regions based on Line Of Response (LOR) and perform reconstruction in a real number coordinate system, allowing for the generation of floating edge LORs and virtual light emission points, enhancing spatial and temporal resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light emission positions are identified in units of scintillator pieces, then the device structure is simple and easy to manufacture, but the spatial resolution and temporal resolution are limited

Engineering Contradiction:
Improvespatial resolutionVSAvoiddetector structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The monolithic scintillator is virtually segmented into multiple virtual scintillator pieces along the depth direction. By calculating the intersection point between the LOR and the scintillator surface, the system determines which virtual piece the light emission belongs to, achieving fine spatial resolution without physical segmentation of the scintillator material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary computational process that maps continuous light emission positions within the monolithic scintillator to discrete virtual detector regions. This intermediary mapping enables the system to achieve discrete measurement capabilities while using a continuous monolithic structure, resolving the contradiction between simplicity and precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If light emission positions are measured in units of scintillator pieces, then the detector design is straightforward, but the TOF temporal resolution is limited to approximately tens of ps

Engineering Contradiction:
Improvetemporal resolutionVSAvoidmeasurement process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent adds a depth dimension to the measurement by calculating the intersection point of the LOR with the scintillator surface. This depth information, combined with light emission position data, creates a more precise spatial-temporal mapping that improves TOF resolution beyond what conventional scintillator piece measurement can achieve.

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

Solution Approach 2:

The system changes the measurement parameters from simple scintillator piece identification to a combination of LOR intersection point calculation and light emission position measurement. This parameter enhancement allows for more precise temporal resolution by incorporating additional spatial information into the measurement process.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a monolithic scintillator is used to enable real number coordinate detection, then spatial and temporal resolution are improved, but the device complexity increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidprocessing circuitry complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the scintillator structure in the form of virtual detector regions. This virtual segmentation allows the system to process continuous coordinate data from the monolithic scintillator using algorithms similar to those used in conventional discrete scintillator systems, managing complexity through computational abstraction.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical segmentation of scintillators with a computational segmentation approach. Instead of physically dividing the scintillator into discrete pieces, the system uses mathematical calculations to define virtual regions, substituting mechanical complexity with computational processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enables higher resolution PET imaging by overcoming theoretical limits, achieving improved spatial and temporal resolution, potentially reaching 10-ps TOF temporal resolution and 1.5-mm spatial resolution.

Implementation Method 1

a PET detector 3, capable of detecting, in a real number coordinate system, a light emission position of an event occurring due to pair annihilation gamma rays becoming incident

Methodology Applied
Scientific EffectScintillation: Scintillation

Data Source

PatentEP4270063B1Pet apparatus, image processing method, and program
Publication Date: 2025.12.17 CANON MEDICAL SYST CORP
  • EP4270063B1 patent drawingFigure 1
  • EP4270063B1 patent drawingFigure 2~3
  • EP4270063B1 patent drawingFigure 4~5

AI summary

A Positron Emission Tomography (PET) apparatus according to an embodiment includes processing circuitry (150). The processing circuitry (150) is configured to determine a virtual detector region (20b, 3b3) on the basis of a Positron Emission Tomography (PET) detector (3) capable of detecting, in a real number coordinate system, a light emission position (5) of an event occurring due to pair annihilation gamma rays becoming incident, a Line Of Response (LOR) (4) defined based on the event detected by the PET detector (100), and the light emission position (5) and is configured to perform a reconstruction process on the basis of the virtual detector region (20b, 3b3).