Expanded Foam MR Coil Former for PET Signal Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MR coil formers made of dense polymers like polycarbonate and polyurethane attenuate PET signals and obscure imaging, while optimizing for MR imagery compromises PET sensitivity, presenting a dilemma in PET-MR scanner design.
Innovation Solution
The use of a lightweight MR coil former with a patient-facing positive surface and a non-patient-facing negative surface, fabricated from low-density expanded foam polymers like EPP, which allows for better PET signal transmission and maintains MR signal quality by positioning the coil array on the positive surface and using a flame barrier-rated coil cover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional dense polymer formers (polycarbonate, polyurethane) are used for MR coil positioning, then structural rigidity and flame barrier protection are improved, but PET signal transmission is attenuated and imaging quality deteriorates
Solution Approach 1:
The former is constructed from composite materials: a rigid foam core (EPS, XPS, or polyurethane foam) providing structural support, and an outer shell of flame-retardant fabric (nylon, polyester, or vinyl) with minimum 14-ounce weight. This composite structure achieves both mechanical strength and PET signal transmission by using low-density foam instead of solid dense polymers, while the flame-retardant fabric layer provides the required fire safety without significantly blocking gamma rays.
Solution Approach 2:
The invention uses rigid foam materials (expanded polystyrene, extruded polystyrene, or polyurethane foam) with cellular porous structures. These porous materials provide the necessary structural rigidity while having low gamma-ray attenuation compared to solid dense polymers. The foam's air-filled cells allow PET photons to pass through with minimal interaction, resolving the contradiction between structural strength and PET signal transmission.
2Reliability
If dense polymer formers are used to provide flame barrier protection, then safety rating (V2 or higher) is improved, but PET photon transmission is blocked and imaging sensitivity is reduced
Solution Approach 1:
The flame barrier function is separated from the main structural material by using a composite construction: the rigid foam core provides structural support and PET transmission, while an outer layer of flame-retardant fabric (nylon, polyester, or vinyl with minimum 14-ounce weight) provides the required flame safety rating. This fabric layer is sufficiently thin and low-density to allow PET photons to pass through while meeting fire safety standards.
Solution Approach 2:
The flame-retardant properties are localized to the outer fabric shell rather than requiring the entire former structure to be made of flame-retardant material. The fabric coating or covering is applied only where flame barrier protection is needed (patient-contact surfaces), allowing the bulk of the former to be made from PET-transparent rigid foam materials.
3Ease of operation
If coil arrays are positioned on the negative (non-patient-facing) surface of the former, then patient comfort and assembly space are improved, but manufacturing complexity and repair difficulty increase due to permanent adhesive requirements
Solution Approach 1:
The invention inverts the conventional approach by positioning the coil arrays on the patient-facing positive surface of the former rather than on the negative surface. This reversal allows coils to be easily accessible for assembly and repair from the patient side, eliminating the need for complex internal routing and permanent adhesives required when coils are mounted on the non-patient-facing surface. The coils remain close to the patient for optimal MR signal detection while being easily serviceable.
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 design enhances PET image quality by reducing gamma ray attenuation and maintains MR signal integrity, allowing for simultaneous high-quality PET and MR imaging without compromising scanner utilization.
Implementation Method 1
This design enhances PET image quality by reducing gamma ray attenuation
Implementation Method 2
Magnetic resonance imaging ('MR') uses RF antenna coils to detect rotating ('relaxation') magnetic fields that are produced by nuclei
Implementation Method 3
the former itself can then provides a flame barrier rated 'V2' or higher (per UL standard 94) between the patient and the high-power detector coils
Data Source
AI summary
An MR coil former apparatus includes a body, a coil array, and a coil cover. The body defines a patient-facing positive surface opposite a non-patient-facing negative surface. The positive surface of the body includes an anatomic contour, and the coil array is disposed adjacent and conformed to the anatomic contour. The coil cover is disposed overlying the coil array and conformed to the anatomic contour.