MRI-Guided Active Breathing Control Valve for Tumor Positioning
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Solution Overview
Problem
Current methods for controlling breathing during MRI and radiotherapy procedures are limited by the reliance on proxy data, which can be inaccurate and prone to drift, leading to motion artifacts in MRI images and uncertainties in tumor positioning during radiotherapy.
Innovation Solution
The ABC device's valve is driven by real-time MRI scanner output, allowing direct measurement of diaphragm or tumor position, enabling precise and reproducible breath holds for improved image acquisition and targeted radiation delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If proxy data from respiratory belts or flow rate integration is used to control breathing, then the system can operate without direct anatomical measurement, but the measurement precision drifts over time and lacks reliability
Solution Approach 1:
The patent replaces mechanical/respiratory proxy measurements (respiratory belts, flow rate integration) with direct MRI-based anatomical measurement. The MRI scanner directly images the diaphragm or tumor position, substituting indirect mechanical sensing with direct electromagnetic imaging to eliminate drift and improve reliability
Solution Approach 2:
The patent introduces MRI imaging as an intermediary measurement system between the breathing mechanism and the control system. Instead of measuring breath directly via respiratory sensors, the system uses MRI to capture anatomical position changes as an intermediate indicator of breathing phase, providing more stable and accurate control signals
2Manufacturing precision
If the valve is controlled by integrated flow rate data, then the system can enforce breath holds, but the position control becomes inaccurate due to drift in computed lung volume
Solution Approach 1:
The patent substitutes computed lung volume measurements (derived from integrated flow rate) with direct MRI-based anatomical position measurements. The MRI scanner provides real-time images of the diaphragm or tumor, replacing the mechanical integration process that accumulates drift errors with direct optical/electromagnetic measurement
Solution Approach 2:
The patent creates a visual copy (MRI image) of the actual anatomical position rather than relying on computed copies from integrated flow data. These image-based position readings serve as accurate replicas of the true anatomical state, enabling precise feedback control without the drift inherent in numerical integration
3Speed
If fast acquisition navigator channel is used to determine breathing phase, then the measurement speed increases, but the direct measurement of anatomy requires integration with the ABC device
Solution Approach 1:
The patent merges the MRI scanner's navigator channel capability with the ABC device's breath-hold enforcement function. The navigator channel provides fast breathing phase detection, and this information is integrated with the ABC valve control system to create a unified breath-hold triggering mechanism, combining diagnostic imaging with therapeutic control
Solution Approach 2:
The patent makes the MRI scanner multi-functional by using its navigator channel not only for imaging purposes but also for real-time breathing phase detection and ABC device triggering. This universal use of the navigator channel eliminates the need for separate sensing systems and reduces overall system complexity despite the sophisticated control required
Data Source
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AI summary
The valve of an active breathing control (ABC) device can be driven by the output of the navigator channel (or another fast-acquisition output) of the MRI scanner, rather than by inference from a measured breath flow rate. This has the advantage that the MRI output can yield a first-hand measurement of the diaphragm position or the tumour position. The computed lung volume obtained from a pneumotachograph is subject to drift over time for a variety of reasons, so a direct measurement of the anatomy will be more reliable. Where the MRI scanner is integrated with a radiotherapy device, the MRI data can be used to trigger the enforced breath-hold by the ABC, and the radiotherapy delivered while the ABC valve is shut. If the MRI data pertains to the actual position of the tumour, then the ABC device will (in effect) hold the tumour at a precise and reproducible point for treatment.