Hybrid Phantom for PET-MR Alignment and Coil Safety
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Solution Overview
Problem
Conventional phantoms are inadequate for calibrating and aligning PET and MRI scanners, as they fail to accommodate the load required by MRI coils during maximum RF power application, potentially damaging the coils and leading to inaccurate image alignment and quality control in hybrid PET-MR scanners.
Innovation Solution
A hybrid phantom with a longitudinal member and end caps, containing a fluid for MRI imaging and radioactive rods for PET imaging, allowing simultaneous or sequential imaging to align the PET and MRI fields of view, and enabling quality control testing of integrated multimodality scanners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional water-based phantoms are used for PET imaging, then PET imaging can be performed, but the MRI coils cannot accommodate the required load during maximum RF power application, potentially damaging the coils and compromising safety
Solution Approach 1:
The phantom changes its physical parameters by replacing water-based material with a specialized material that has different electromagnetic properties. This material allows the phantom to support maximum RF power application without overheating or damaging MRI coils, while still maintaining PET imaging compatibility through its radioactive substance content
Solution Approach 2:
The phantom uses a composite structure combining a specialized load-bearing material (to protect MRI coils during RF power application) with radioactive substances (for PET imaging). This composite approach allows simultaneous functionality for both PET and MRI systems without compromising safety
2Measurement precision
If separate water-based phantoms are used for PET and MRI calibration, then each modality can be calibrated independently, but alignment inaccuracies occur and multiple separate phantoms are required
Solution Approach 1:
The patent merges PET and MRI calibration functionality into a single integrated phantom. The phantom contains both PET radioactive substances and MRI-compatible materials with identifiable features, allowing simultaneous calibration and alignment verification of both modalities in one device, thereby improving alignment accuracy and reducing system complexity
Solution Approach 2:
The phantom is designed with multi-functionality to serve both PET and MRI calibration purposes simultaneously. It includes PET radioactive substances for emission imaging calibration and MRI-visible features (such as specific material densities or electromagnetic properties) for anatomical and alignment verification, making it a universal calibration tool for hybrid PET-MRI systems
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 phantom provides accurate alignment and quality control for PET-MR scanners by allowing simultaneous imaging, reducing alignment inaccuracies and ensuring safe operation of MRI coils, while eliminating the need for separate water-based phantoms and associated hazards.
Implementation Method 1
MRI scans use a powerful magnetic field to align the magnetization of hydrogen atoms in the body. Radio waves are used to systematically alter the alignment of such magnetization, thereby causing the hydrogen atoms to produce a rotating magnetic field detectable by the MRI system.
Implementation Method 2
As the radioisotope undergoes positron emission decay (also known as positive beta decay), it emits a positron, the antimatter counterpart of an electron. After travelling up to a few millimeters, the positron encounters and annihilates with an electron, producing a pair of annihilation (gamma) photons moving in opposite directions
Implementation Method 3
the positron encounters and annihilates with an electron, producing a pair of annihilation (gamma) photons moving in opposite directions
Data Source
AI summary
A phantom for co-registering a magnetic resonance image and a nuclear medical image is disclosed. The phantom includes a longitudinal member having a first end cap and a second end cap and a chamber contained within the longitudinal member. The chamber contains a fluid for producing a first image using a first imaging modality. The phantom further includes a first rod disposed within the chamber of the longitudinal member. The first rod contains a radioactive substance for producing a second image using a second imaging modality.