Lightweight 3D Phantom for MR Radiation Therapy Distortion Mapping
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Solution Overview
Problem
Current medical imaging phantoms for radiation therapy planning are heavy, difficult to move, and do not accurately measure geometric distortions across the entire 3D imaging volume, wasting clinical time and resources, and there is a lack of standard quality assurance for MR images used in radiation therapy planning.
Innovation Solution
A lightweight medical imaging phantom weighing less than 18.2 kg with a 3D spatial distribution of MR and CT imagable elements in an inert foam support, surrounded by a hermetically sealed external support structure, designed to completely fill the imaging volume of an MR device, allowing for easy handling and accurate distortion mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heavy 3D phantoms (45-90 kg) are used for MR scanner calibration, then the entire field of view can be measured, but the phantom becomes difficult to move and may not measure the entire field of view due to weight limitations
Solution Approach 1:
The phantom is divided into multiple removable inserts that can be individually placed and positioned within the imaging volume. Each insert contains imaging elements for distortion measurement, and multiple inserts together cover the entire field of view without requiring a single heavy structure. This segmentation allows the phantom to be easily moved while maintaining comprehensive measurement capability.
2Ease of operation
If 2D grid phantoms are used for distortion mapping, then the phantom can be easily positioned and imaged in different planes, but multiple images and repeated physical movement are required representing possible imaging planes
Solution Approach 1:
The phantom transitions from 2D grid structures to 3D volumetric inserts with imaging elements distributed throughout the entire imaging volume. This dimensional change allows single-image capture of distortion data across all three spatial dimensions, eliminating the need for multiple sequential images and repeated phantom repositioning while maintaining ease of operation.
3Device complexity
If 2D phantoms are used for distortion mapping, then the phantom structure is simple, but distortion measurement is limited to positions where the 2D phantom is placed
Solution Approach 1:
The phantom design incorporates 3D volumetric inserts with imaging elements distributed throughout the entire imaging volume rather than confined to 2D planes. This dimensional expansion enables distortion measurement at multiple positions simultaneously across the full 3D field of view, significantly improving measurement coverage while maintaining reasonable structural complexity through modular insert design.
Data Source
AI summary
A system (20) for quality assurance of a magnetic resonance (MR) imaging device (23) used in magnetic resonance based radiation therapy planning includes a phantom (10) weighing less than 18.2 kg (40 lbs.). The phantom includes a three dimensional spatial distribution of MR and CT imagable elements (12) located in an MR and CT inert foam support (14), and an MR and CT inert external support structure (16) which surrounds and hermetically seals the foam support. The spatial distribution is sized to completely fill an imaging volume of the magnetic resonance imaging device.