Multi-Modality Imaging Alignment Using Annulus Phantom Scans
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Solution Overview
Problem
Existing multi-modality imaging systems rely on large and expensive volumetric quality control (VQC) phantoms for aligning components, which are burdensome to maintain and store due to their occasional use.
Innovation Solution
A method involving multiple scans of an annulus phantom in different orientations to calculate alignment parameters for accurately aligning multi-modality imaging system components without the need for dedicated VQC phantoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated volumetric quality control (VQC) phantom is used for aligning PET and CT components, then alignment precision is improved, but device complexity, cost, and maintenance burden increase
Solution Approach 1:
The patent replaces the complex dedicated VQC phantom with a simple annulus phantom that copies only the essential geometric feature needed for alignment - a circular shape with a well-defined center. This simplified copy retains sufficient information for calculating alignment parameters while eliminating unnecessary complexity, radioactive materials, and expensive construction requirements.
Solution Approach 2:
The annulus phantom is a simple, inexpensive, non-radioactive object that can be easily manufactured and replaced if needed. Unlike expensive dedicated VQC phantoms containing radioactive spheres that require special handling, storage, and regulatory compliance, the annulus phantom eliminates these burdens while providing sufficient alignment information.
2Measurement precision
If a dedicated VQC phantom with radioactive spheres is used, then alignment accuracy is improved, but ease of operation and maintenance deteriorate due to storage and handling requirements
Solution Approach 1:
The annulus phantom eliminates radioactive materials entirely, replacing them with a simple geometric shape that requires no special licensing, storage facilities, or safety protocols. This makes the phantom easy to handle, store, and maintain while providing sufficient alignment accuracy through its well-defined geometric center.
3Measurement precision
If multiple scans in different orientations are performed with a simple phantom, then alignment parameter calculation is enabled, but scanning time increases
Solution Approach 1:
The patent performs scans in multiple orientations (excessive action) to ensure accurate determination of the annulus center and alignment parameters. While this requires more than a single scan, the simple geometry of the annulus phantom makes each scan quick, and the additional orientations provide redundant information that improves accuracy without requiring excessive time.
Data Source
AI summary
Methods and systems are provided for aligning components of a multi-modality imaging system. In one embodiment, a method comprises performing a plurality of scans of an object with a first modality and a second modality, wherein the object is positioned in a different orientation in each of the plurality of scans, calculating a plurality of alignment parameters of a first modality unit and a second modality unit based on the plurality of scans, and adjusting alignment of the first modality unit and the second modality unit based on the plurality of alignment parameters. In this way, components of a multi-modality imaging system may be accurately aligned using any phantom from which a unique line can be extracted in each modality scan.