PET Scanner Step-Size Optimization for Axial FOV Waste Reduction

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Solution Overview

Problem

Conventional PET scanners waste significant imaging resources due to fixed step-size scanning, leading to undershoot or overshoot of the targeted region of interest, especially in larger axial FOVs, resulting in inefficient use of time and counts outside the area of interest.

Innovation Solution

A method and apparatus for optimizing PET scanner step-size using a minimum number deriving unit, excess length deriving unit, and starting point deriving unit to determine the necessary number of overlapping scans and their overlap percentage, ensuring precise allocation of excess length on both ends of the region of interest, thereby minimizing waste and optimizing resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If fixed step-size scanning is used, then the scanning process is simple, but imaging resources are wasted due to undershoot or overshoot of the targeted region of interest

Engineering Contradiction:
Improvescanning process simplicityVSAvoidimaging resources waste
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the step-size adjustable rather than fixed. The scanning step-size is dynamically determined based on the axial FOV length and the targeted region of interest, allowing the system to adapt to different imaging scenarios and eliminate waste while maintaining operational simplicity through automated calculation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of step-size from a fixed value to a variable that is calculated based on specific parameters (axial FOV length, targeted region of interest). This parameter change enables precise control over the scanning range, ensuring that the scanner covers exactly the needed area without unnecessary overlap or omission, thereby reducing imaging resource waste.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If fixed step-size scanning is used, then the device complexity is low, but time and counts are inefficiently used outside the area of interest

Engineering Contradiction:
Improvescanning control complexityVSAvoidimaging time efficiency
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by calculating the optimal step-size before the scanning process begins. The step-size is determined in advance based on the axial FOV length and the targeted region of interest, allowing the scanner to be configured for optimal performance prior to acquisition. This preliminary calculation ensures that time and counts are efficiently allocated only to the area of interest, eliminating waste during the actual scanning process.

Inventive Principle:
Principle #10Preliminary action

3Area of stationary object

If larger axial FOV is used, then the coverage area is increased, but the waste area outside the region of interest increases

Engineering Contradiction:
Improveaxial FOV coverageVSAvoidimaging resources waste
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The patent applies local quality by tailoring the step-size to match the specific needs of the targeted region of interest within the axial FOV. Instead of using a uniform fixed step-size across the entire FOV, the system adjusts the step-size locally to ensure optimal coverage of the region of interest while minimizing coverage of areas outside this region, thereby reducing imaging resource waste in larger axial FOV configurations.

Inventive Principle:
Principle #3Local quality

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 significantly reduces waste areas outside the region of interest, enhancing the efficiency of imaging resources and improving the overall sensitivity profile, particularly in larger axial FOVs, by adjusting the step-size and scanning time to match the actual length of the imaging area.

Implementation Method 1

when an emitted positron collides with an electron, an annihilation event occurs, wherein the positron and the electron are destroyed. Most of the time, an annihilation event produces two gamma rays (at 511 keV) emitted at substantially 180 degrees apart.

Methodology Applied
Scientific EffectAnnihilation:

Data Source

PatentEP2667222B1Positron emission computed tomography device, method executed by positron emission computed tomography device, and program
Publication Date: 2018.03.21 TOSHIBA MEDICAL SYST CORP
  • EP2667222B1 patent drawingFigure 1~2
  • EP2667222B1 patent drawingFigure 3
  • EP2667222B1 patent drawingFigure 4

AI summary

A positron emission computed tomography apparatus according to an embodiment includes a minimum number deriving unit (170), an excess length deriving unit (170), and a starting point deriving unit (170). The minimum number deriving unit (170) derives a minimum number that is the number of scans in a case where multiple scans are successively performed and that is necessary to image at least an axial extent of a region of interest. The excess length deriving unit (170) derives an excess length that is excessively scanned by the scans in the axial direction based on the minimum number of scans, the axial extent of the region of interest, and the length of an axial FOV. The starting point deriving unit (170) derives a starting point of a first scan of the scans so that the excess length is equally allocated on each end of the region of interest in the axial direction.