Modular Power Distribution for MR-PET Signal Integrity
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Solution Overview
Problem
The integration of magnetic resonance (MR) and positron emission tomography (PET) systems faces challenges due to electromagnetic interference (EMI) and electromagnetic compatibility (EMC) issues, particularly with the MR subsystem being sensitive to RF emissions from the PET subsystem, which affects signal integrity and timing precision in PET imaging.
Innovation Solution
A modular power distribution architecture is implemented, with each data processing unit in the PET subsystem receiving a discrete DC power supply, and these units are configured with galvanic isolation from each other to minimize interference. Additionally, the PET subsystem components, including data processing units, are placed within the RF cabin to reduce signal distortion and cabling requirements, utilizing a thermal management system to handle heat generated by these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PET detectors and data processing units are placed outside the RF cabin, then EMI and EMC issues with the MR subsystem are avoided, but signal integrity and timing precision deteriorate due to long cabling
Solution Approach 1:
A modular power distribution architecture with discrete DC power supplies and galvanic isolation is introduced as an intermediary system. This allows PET data processing units to be placed inside the RF cabin while maintaining electrical isolation from external interference, thus protecting signal integrity without requiring long external cabling
Solution Approach 2:
The power distribution system is segmented into multiple discrete DC power supplies, each independently powering individual data processing units. This segmentation enables modular placement of processing units within the RF cabin while maintaining independent power isolation, reducing susceptibility to EMI and EMC issues
2Manufacturing precision
If PET detectors are placed as an insert in front of the body coil, then overlapping fields of view are achieved, but EMI sensitivity increases due to proximity to MR RF emissions
Solution Approach 1:
Galvanic isolation acts as an intermediary barrier between the PET detectors and the MR RF emissions. The isolated power distribution system allows the detectors to be positioned close to the body coil for optimal spatial correlation while protecting the sensitive electronics from RF interference through electrical isolation
3Device complexity
If data processing units share a common power supply, then system complexity is reduced, but electromagnetic interference between units increases
Solution Approach 1:
The common power supply is segmented into multiple discrete DC power supplies, with each unit receiving isolated power. This segmentation reduces EMI between processing units by eliminating shared electrical pathways, while the modular nature of the discrete power supplies keeps the overall system complexity manageable
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 configuration maintains PET signal data integrity, improves timing precision, reduces signal losses, and minimizes the volume and weight of cabling, thereby enhancing the performance and integration of MR and PET systems while reducing performance limitations.
Implementation Method 1
a plurality of power supply modules, each power supply module being operable to generate a DC power supply for different groups of one or more of the data processing units
Implementation Method 2
The MR body coil is used to excite the molecules of the patient by delivering an RF burst
Implementation Method 3
The MR switches into a receive mode, after delivery of the RF burst, and detects RF signals emitted from the patient
Implementation Method 4
a typical MR system is enclosed in a radio frequency (RF) cabin that suppresses RF signals, such as by 100 dB, for both external signals entering the RF cabin and internal signals exiting the RF cabin
Data Source
AI summary
An integrated magnetic resonance (MR) and positron emission tomography (PET) system includes an MR scanner including a magnet that defines an opening in which a subject is positioned, a set of PET detectors disposed about the opening, a plurality of data processing units each electrically connected with a respective one or more of the PET detectors of the set of PET detectors, and a plurality of power supply modules, each power supply module being operable to generate a DC power supply for different groups of one or more of the data processing units. Each power supply module is discrete from the other power supply modules.