3D Phantom for Deformable Image Registration Quality Assurance
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Solution Overview
Problem
Current deformable image registration (DIR) quality assurance methods in medical imaging are limited by the use of two-dimensional phantoms, which are not compatible with DIR algorithms, making it difficult to distinguish between customization errors and algorithmic discrepancies, and thus affecting patient treatment accuracy.
Innovation Solution
A three-dimensional phantom system is developed, comprising tissue models made of thermoplastic materials with varying radiodensities to mimic mammalian anatomy, allowing for the comparison of measured optical deformations with theoretical deformations using CT images and deformable registration algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-dimensional phantom system is used for DIR quality assurance, then the phantom construction is simplified, but the compatibility with DIR algorithms is poor and customization errors cannot be distinguished from algorithmic discrepancies
Solution Approach 1:
The patent transitions from a two-dimensional phantom system to a three-dimensional phantom system. The 3-D phantom comprises multiple tissue models with different radiodensities that can be deformed in three dimensions, fully compatible with DIR algorithms used in clinical practice. This dimensional upgrade eliminates the incompatibility issues while maintaining manufacturing feasibility through modular tissue model construction.
2Measurement precision
If a three-dimensional phantom system is developed with multiple tissue models of different radiodensities, then the compatibility with DIR algorithms and measurement accuracy are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The 3-D phantom is segmented into multiple discrete tissue models, each representing different anatomical tissues with specific radiodensities. Each tissue model can be independently manufactured and then assembled into the complete phantom system. This segmentation reduces the overall manufacturing complexity by breaking down the complex 3-D structure into manageable components while maintaining the ability to provide accurate multi-tissue deformation measurements.
Solution Approach 2:
Different regions of the phantom system (different tissue models) are assigned different radiodensities and material properties to match specific anatomical tissues. This local differentiation allows each tissue model to be optimized for its specific measurement requirements while contributing to the overall accuracy of the DIR quality assurance system.
3Manufacturing precision
If thermoplastic materials with varying radiodensities are used to create tissue models, then the radiographic accuracy and anatomical mimicry are improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent utilizes thermoplastic materials whose radiodensity can be adjusted by changing material composition parameters. Different thermoplastic compounds or formulations are selected to match the radiodensities of different anatomical tissues. This parameter-based approach allows for precise radiodensity matching while using a relatively simple class of materials (thermoplastics) that can be manufactured using standard techniques.
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 three-dimensional phantom system provides accurate measurements of deformations, enabling improved quality assurance for DIR algorithms, thereby enhancing treatment planning and reducing errors in radiation oncology by differentiating between actual and theoretical deformations.
Implementation Method 1
heating the non-deformed radiographic three-dimensional phantom to a temperature at which some or all of the phantom material of the non-deformed radiographic three-dimensional phantom is malleable
Implementation Method 2
generating a first plurality of computer tomography (CT) images from the non-deformed radiographic three-dimensional phantom and a second plurality of CT images from the deformed radiographic three-dimensional phantom, which first and second plurality of CT images are taken at varying depths
Data Source
AI summary
There is provided a radiographic three-dimensional phantom for inter alia mimicking specific anatomical parts in a computerized tomography scan. Methods are provided for a variety of purposes including detecting a difference between a measured optical deformation of a radiographic three-dimensional phantom pair and a theoretical deformation of the radiographic three-dimensional phantom pair. These three-dimensional phantom can be divided into a plurality of portions, and non-radiopaque markers can be added to the portions. The portions of the three-dimensional phantom can be re-assembled, and images of the three-dimensional phantom can be generated and compared.