Hybrid TOF-PET/MRI Tomograph with Nonmagnetic Scintillation Strips
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Solution Overview
Problem
Current hybrid PET/MRI tomographs face challenges in achieving simultaneous imaging due to interference between PET and MRI systems, leading to image distortions and artefacts, especially when abdominal organs move during sequential scanning, and existing solutions either reduce imaging quality or are costly and impractical for large-scale production.
Innovation Solution
A hybrid TOF-PET/MRI tomograph design featuring nonmagnetic polymer scintillation strips as the detection layer, which allows for simultaneous registration of gamma radiation and MRI imaging without interfering with magnetic fields, using photoelectric converters outside the MRI magnet and employing light-guiding properties to transmit signals outside the magnetic field, enabling precise and artifact-free imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PET and MRI tomographs are spatially separated and aligned in close proximity, then interference between systems is reduced, but object movement between sequential imaging causes image distortions and artefacts
Solution Approach 1:
The patent merges PET and MRI tomographs into a single integrated hybrid device with a common examination chamber, allowing simultaneous imaging of the object. This eliminates the need to move the object between separate devices, preventing image distortions and artefacts while maintaining reduced interference through careful spatial arrangement of detection systems.
2Productivity
If PET detectors are placed inside MRI magnet, then simultaneous imaging is enabled, but magnetic fields interfere with photoelectric converters and signal transmission
Solution Approach 1:
The patent uses optical fibres as intermediaries to transmit light signals from scintillation crystals to photoelectric converters. The scintillation crystals convert gamma radiation to light within the magnetic field zone, and the optical fibres conduct these light signals to photodetectors positioned outside the high magnetic field region, thereby isolating sensitive electronic components from magnetic interference while enabling simultaneous imaging.
Solution Approach 2:
The patent replaces direct electrical signal transmission through wires with optical signal transmission through optical fibres. This substitution eliminates the problem of electromagnetic interference and eddy currents in metallic components within the MRI magnet, as optical fibres are non-conductive and immune to magnetic field effects.
3Measurement precision
If standard inorganic scintillation materials are used in PET detectors, then gamma radiation detection is effective, but the materials are magnetic and interfere with MRI magnetic fields
Solution Approach 1:
The patent changes the magnetic property parameter of the scintillation material by selecting non-magnetic or weakly magnetic materials such as LSO (Lutetium Oxyorthosilicate) or LYSO (Lutetium Yttrium Oxyorthosilicate) crystals. These materials maintain effective gamma radiation detection capabilities while being compatible with MRI magnetic fields, thus resolving the contradiction between detection precision and magnetic field stability.
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
Enables simultaneous and artifact-free functional and morphological imaging with a large field of view, eliminating the need for object movement and reducing systematic errors, while being cost-effective and suitable for large-scale production.
Implementation Method 1
The strip device comprises nonmagnetic polymer scintillation strips
Implementation Method 2
one or more photodetectors, which are optically connected to the at least one strip of scintillators
Implementation Method 3
The photodetectors and the associated readout electronics are arranged outside the central region of the magnetic field. The optical fibres enable the light impulses to be transmitted outside the magnets of the MRI tomograph
Implementation Method 4
a main magnet that generates a magnetic field, wherein images of the subject is generated in a central region of the magnetic field
Implementation Method 5
coil magnets producing gradient field
Data Source
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AI summary
A hybrid TOF-PET/MRI tomograph comprising a TOF-PET tomograph and an MRI tomograph, wherein the TOF-PET tomograph (120) comprises polymer scintillation strips (121) arranged circumferentially inside the working area of the magnetic field of the receiving-transmitting coil (131) of the MRI tomograph (130) and photoelectric converters (122) for converting light signals from the scintillation strips (121) to electrical signals, wherein the photoelectric converters (122) are arranged outside the working area of magnetic field of the MRI tomograph (130).