Split Gradient Coil with Central Gap for PET Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetic resonance scanners with central gaps in gradient coil assemblies are inefficient due to small gap widths, limiting the installation of PET detector arrays and degrading magnetic field gradient efficiency, and hybrid scanners face challenges in accommodating PET detectors and maintaining image quality.
Innovation Solution
A magnetic field gradient coil design with an arcuate or annular central gap of at least 10 centimeters, connected by conductors to enhance coil efficiency and accommodate PET detectors, along with an active shim system to correct magnetic field inhomogeneities induced by PET detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small central gap is used in the gradient coil assembly, then the magnetic field gradient efficiency is maintained, but the installation of PET detector arrays is limited
Solution Approach 1:
The gradient coil assembly is divided into two separate halves that can be independently positioned and connected. This segmentation allows for a larger central gap to accommodate PET detectors while maintaining the magnetic field gradient efficiency through proper electrical connection of the segmented windings.
Solution Approach 2:
The patent transitions from a continuous gradient coil structure to a segmented structure with a central gap, utilizing the radial dimension to create space for PET detectors. This dimensional change allows both gradient coil functionality and PET detector installation to coexist within the same bore space.
2Adaptability or versatility
If a large central gap is used in the gradient coil assembly, then PET detector arrays can be installed, but the magnetic field gradient efficiency degrades
Solution Approach 1:
The gradient coil windings are segmented into two halves that are electrically connected through connecting conductors. This segmentation allows the coil to function as a unified structure for generating magnetic field gradients while creating a large central gap for PET detector installation, thus resolving the efficiency degradation issue.
Solution Approach 2:
Connecting conductors act as intermediaries to electrically link the two separated halves of the gradient coil assembly. These conductors ensure that the segmented structure maintains the necessary electrical continuity to generate efficient magnetic field gradients despite the physical separation and large central gap.
3Adaptability or versatility
If the gradient coil assembly is split into two halves, then PET detectors can be accommodated, but mechanical movement under Lorentz forces requires additional spacing
Solution Approach 1:
The gradient coil assembly is segmented into two halves that are mechanically and electrically connected. This segmentation provides the necessary structure to accommodate PET detectors while the connection mechanism ensures that mechanical movement under Lorentz forces is controlled and does not require excessive spacing.
Solution Approach 2:
The two halves of the gradient coil assembly are merged through electrical connection via connecting conductors. This merging allows the system to function as a unified structure that can accommodate PET detectors while maintaining mechanical stability and minimizing the spacing required for mechanical movement accommodation.
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 design provides improved magnetic field gradient efficiency, allows for the installation of PET detector arrays, and enhances image quality by maintaining vibrational isolation and uniformity, enabling effective hybrid MR/PET scanning.
Implementation Method 1
the generally cylindrical set of coil windings being operable to superimpose a transverse magnetic field gradient on an axially oriented static magnetic field
Implementation Method 2
connecting conductors disposed at each edge of the central gap that electrically connect selected primary and secondary coil windings
Implementation Method 3
A generally cylindrical gradient coil assembly is disposed coaxially inside the main magnetic field windings to selectively superimpose magnetic field gradients on a main magnetic field
Data Source
AI summary
A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.