Optically Coupled Readout Front-End for PET/MRI Interference

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Solution Overview

Problem

Current PET technology has poor spatial resolution, making unambiguous localization of signals difficult, and integrating PET with MRI is challenging due to interference and compatibility issues in high magnetic fields.

Innovation Solution

A magnetically-insensitive high-energy photon detector system using optical coupling to transmit signals outside the MRI system, reducing electrical connections and interference, and employing semiconductor detectors and VCSELs for robust signal amplification and transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If PET detectors are placed inside MRI system to enable simultaneous imaging, then functional imaging capability is improved, but electrical interference and noise injection into MRI RF pickup occurs

Engineering Contradiction:

Improvesimultaneous imaging capabilityVSAvoidelectrical interference and noise

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces electrical signal transmission with optical signal transmission using photodetectors and optical fibers. The PET detector signals are converted to optical signals that can be transmitted through optical fibers to external processing electronics, eliminating electrical connections inside the MRI bore and preventing RF interference while enabling simultaneous PET/MRI imaging

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical fibers as an intermediary medium to transmit PET detector signals outside the MRI system. The optical fibers act as a barrier that isolates the PET electronics from the MRI RF environment while allowing signal transmission, thus preventing noise injection into the MRI RF pickup

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If PET electronics are integrated into MRI system, then compactness is improved, but device complexity and susceptibility to magnetic field interference increase

Engineering Contradiction:

Improvesystem compactnessVSAvoidintegration complexity

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent divides the imaging system into two separate but synchronized subsystems: PET detection components (scintillation crystals, photodetectors) placed inside the MRI bore for compact integration, and processing electronics located outside the MRI system to avoid magnetic field interference. This segmentation allows compact simultaneous imaging while reducing overall system complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces complex shielded electrical connections with simpler optical fiber connections. The optical coupling mechanism is mechanically simpler and more robust than attempting to create magnetically shielded electrical pathways, thus reducing integration complexity while maintaining compactness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If higher magnetic fields are used in MRI to improve signal-to-noise ratio, then spatial resolution and contrast are improved, but susceptibility effects and physiological noise increase

Engineering Contradiction:

Improvespatial resolutionVSAvoidsusceptibility effects and physiological noise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent merges PET functional imaging with MRI anatomical imaging into a single simultaneous acquisition system. The PET modality provides metabolic and functional information that complements MRI's high spatial resolution anatomical data, creating a synergistic effect where the combination of modalities compensates for the drawbacks of each individual modality at high magnetic fields

Inventive Principle:

Principle #5Merging (Combining)

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 PET and MRI imaging with improved spatial resolution and minimal interference, allowing for uncompromised performance of both modalities, especially in high-field MRI environments.

Implementation Method 1

employing semiconductor detectors and VCSELs for robust signal amplification and transmission

Methodology Applied

Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

A receiver may also be provided, which is optically coupled to the interface to receive the optical signal and convert the optical signal into a voltage signal

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS8868154B2Optically coupled readout front-end for imaging system

Publication Date: 2014.10.21 BOARD OF TRUSTEES OF THE LELAND STANFORD JURNIOR UNIV

AI summary

A front end for an imaging system. The front end comprises at least one magnetically-insensitive high-energy photon detector and an interface for converting an output of the at least one high-energy photon detector to an optical signal and transmitting the optical signal. A receiver is optically coupled to the interface to receive the optical signal and convert the optical signal into a voltage signal.