Axially Adjustable PET Detector Rings for Dynamic Field of View

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Solution Overview

Problem

Current positron emission tomography (PET) scanners face challenges in achieving a flexible and adaptive axial field of view (aFOV) without increasing the number of detector rings, leading to decreased signal-to-noise ratio and loss of incident events due to fixed detector ring positions, which limits their effectiveness in capturing dynamic data from entire body regions of interest.

Innovation Solution

The implementation of axially-adjustable PET detector rings, controlled by a processing unit that adjusts their positions based on attenuation data and scan mode information, allowing for uniform arrangement and optimal spacing to maintain sensitivity and image quality across varying patient sizes and shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the axial field of view (aFOV) is increased by adding more detector rings, then the coverage of the imaging area is improved, but the system cost and device complexity increase

Engineering Contradiction:
Improveaxial field of view coverageVSAvoidnumber of detector rings
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the detector rings movable along the axial direction. Each detector ring can be independently positioned to adjust the aFOV based on patient anatomy, eliminating the need for fixed additional detector rings. This dynamic adjustment capability allows the system to achieve variable coverage without permanently increasing the number of detector components.

Inventive Principle:
Principle #15Dynamics

2Area of stationary object

If larger gaps are introduced between adjacent PET detector rings to increase aFOV, then the coverage area is improved, but the signal-to-noise ratio decreases and incident events are lost

Engineering Contradiction:
Improveaxial field of viewVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The detector rings are designed to be dynamically adjustable along the axial direction, allowing the gaps between rings to be optimized based on the specific imaging requirements and patient anatomy. This dynamic positioning enables the system to maintain adequate detector coverage while achieving the desired aFOV, preventing permanent signal loss that would occur with fixed large gaps.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by allowing different detector rings to be positioned at different axial locations based on the specific imaging needs. This enables optimal spacing between detectors in different regions, maintaining signal quality in critical areas while extending coverage in others, rather than applying a uniform gap structure throughout.

Inventive Principle:
Principle #3Local quality

3Device complexity

If fixed detector ring positions are used, then the device complexity is reduced, but the adaptability to different patient sizes and scan modes is limited

Engineering Contradiction:
Improvedetector positioning systemVSAvoidadaptability to patient anatomy
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system implements dynamic detector ring positioning where each ring can be independently adjusted along the axial direction based on patient-specific anatomical characteristics and scan mode requirements. This dynamic capability provides high adaptability to different patient sizes and imaging applications without requiring a permanently complex positioning infrastructure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the positional parameters of the detector rings dynamically based on input data regarding patient anatomy and scan mode. By adjusting the axial positions of detector rings according to varying parameters (patient size, scan type), the system achieves high adaptability while maintaining a relatively simple base configuration.

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

This approach enhances the geometric coverage and sensitivity of PET scans, enabling improved diagnostic imaging by adjusting detector ring positions to match patient anatomy, thereby reducing image noise and data gaps, and improving the utility of PET in various clinical applications.

Implementation Method 1

the positron emitter attached to the pharmaceutical agent will emit positrons according to the physical properties of the isotope

Methodology Applied
Scientific EffectPositron emission: Radioactive Decay

Implementation Method 2

Emitted positrons collide with an electron of the imaging object, or patient, resulting in an annihilation of the positron and electron and generation of two gamma rays at 511 keV in opposite directions

Methodology Applied
Scientific EffectAnnihilation: Reaction (physics)

Implementation Method 3

PET scanners, which include several PET detector rings for detecting the generated gamma rays

Methodology Applied
Scientific EffectGamma ray detection: Absorption (EM radiation)

Data Source

PatentEP3915479A1Positron emission tomography apparatus, method and computer-readable storage medium
Publication Date: 2021.12.01 CANON MEDICAL SYST CORP
  • EP3915479A1 patent drawingFigure 1A~1B
  • EP3915479A1 patent drawingFigure 1C
  • EP3915479A1 patent drawingFigure 2

AI summary

A positron emission tomography (PET) apparatus according to an embodiment includes a plurality of PET detector rings (101, 601, 701, 901, 1001, 1101) and a processing unit (307). The plurality of PET detector rings (101, 601, 701, 901, 1001, 1101) is configured to form a bore in which a subject is placed, and to be adjustable in position in an axial direction, the bore defining a field of view (FOV) of the apparatus. The processing unit 307) is configured to obtain information regarding a PET scan mode, and to adjust, based on the information regarding the PET scan mode, position of each of the plurality of PET detector rings (101, 601, 701, 901, 1001, 1101) from a first position to a second position in the axial direction.