Directional Phantom for CT Contrast Calibration
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Solution Overview
Problem
Current imaging technologies face challenges in accurately calibrating contrast imaging, particularly in dynamic contrast-enhanced CT imaging, due to motion artifacts and beam hardening effects, which affect the measurement of kinetic parameters and contrast agent concentration, especially in organs like the liver and lung, where breathing motion introduces blurring and reconstruction errors.
Innovation Solution
An imaging phantom with directional cavities and capsules made of materials like Teflon, designed to mimic tissue and bone, is used to quantify and model contrast enhancement under various motion conditions, allowing for calibration of CT scanners and assessment of patient dose, incorporating a motion device to simulate breathing motion and gantry rotation times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If DCE-CT imaging is performed under free-breathing conditions to improve patient comfort and reduce breath-hold requirements, then ease of operation is improved, but motion artifacts and reconstruction errors increase, worsening measurement precision
Solution Approach 1:
The patent creates a phantom that copies the anatomical and motion characteristics of real organs (liver, lung) to simulate breathing motion artifacts. This allows researchers to study and develop correction methods without requiring actual patient scans, thus resolving the contradiction by enabling precision measurement studies under comfortable free-breathing conditions through phantom modeling.
Solution Approach 2:
The phantom acts as an intermediary between the CT scanner and real patients, providing a controlled medium to study motion artifacts. By placing the phantom on a motion platform that simulates breathing, researchers can intermediate the study of motion effects without the variability and ethical constraints of human subjects, improving both ease of operation and measurement precision.
2Measurement precision
If high scanning frequency is employed to reduce motion-induced blurring, then measurement precision is improved, but use of energy and productivity may be affected due to longer scan times required for calibration
Solution Approach 1:
The phantom enables preliminary calibration and characterization of motion artifacts before actual patient scans. By pre-characterizing the relationship between motion parameters and image artifacts using the phantom, researchers can optimize scanning protocols and correction algorithms in advance, reducing the need for repeated high-energy scans during actual measurements.
Solution Approach 2:
The phantom allows for partial calibration studies using controlled motion amplitudes and frequencies that represent worst-case scenarios. By calibrating with exaggerated motion parameters, the system can achieve sufficient precision for clinical applications without requiring exhaustive calibration at every possible scanning parameter combination, thus reducing energy consumption.
3Measurement precision
If limited field-of-view is used to focus on specific vessels of interest, then measurement precision for those vessels is improved, but vessels may periodically move out of the plane of interest during breathing, worsening reliability
Solution Approach 1:
The phantom is mounted on a motion platform that dynamically simulates breathing motion, allowing researchers to study how vessels move in and out of the field-of-view during respiration. This dynamic modeling enables the development of adaptive sampling strategies and motion compensation techniques that maintain reliable vessel sampling despite breathing-induced position changes.
Solution Approach 2:
The phantom contains vessels at different orientations and positions relative to the expected motion direction. By including asymmetric vessel arrangements, researchers can study how different vessel configurations are affected by breathing motion and develop targeted solutions for maintaining consistent sampling of critical vessels throughout the respiratory cycle.
4Ease of manufacture
If conventional calibration phantoms are used that are designed for static conditions, then ease of manufacture is improved, but they become inadequate for dynamic imaging applications, worsening adaptability
Solution Approach 1:
The dynamic calibration phantom is segmented into multiple functional components: a base phantom structure containing vessels and contrast agents, a motion platform for simulating breathing, and a control system. This segmentation allows each component to be manufactured and optimized independently, maintaining ease of manufacture while enabling dynamic calibration capabilities that conventional static phantoms cannot provide.
Data Source
AI summary
An imaging phantom for contrast imaging calibration. The phantom includes a body defining at least one cavity having a directional configuration corresponding to at least one pre-determined direction of motion of the phantom. The phantom also includes at least one imaging capsule configured to match and be contained in the at least one cavity. The imaging capsule comprises a material having an imaging contrast different from that of the body.