Respiratory Biofeedback for MRI-Guided Radiotherapy Targeting
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Solution Overview
Problem
Existing radiotherapy systems face challenges in accurately targeting moving organs due to respiratory motion, particularly in abdominal and thoracic regions, as conventional methods struggle to synchronize breathing patterns between imaging and treatment phases.
Innovation Solution
A medical system that utilizes a time-resolved magnetic resonance imaging dataset synchronized with a breath monitor system to provide real-time biofeedback, allowing patients to match their breathing pattern with that of the imaging phase, thereby improving targeting accuracy by adjusting radiotherapy system control commands based on current and desired breathing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radiotherapy methods are used without breathing synchronization, then treatment can proceed continuously, but targeting accuracy deteriorates due to respiratory motion of target organs
Solution Approach 1:
The system implements a feedback mechanism where the patient's breathing phase is continuously monitored and displayed in real-time on a user interface. The radiotherapy system receives feedback about the current breathing phase and adjusts the irradiation timing accordingly, delivering radiation only during the desired breathing phase when the target organ is in the correct position. This closed-loop feedback ensures high targeting accuracy while maintaining treatment efficiency.
Solution Approach 2:
The system dynamically adapts the radiotherapy delivery timing based on the patient's real-time breathing motion. Instead of using a static treatment plan, the system continuously adjusts the irradiation timing to match the dynamic breathing cycle, allowing the treatment to proceed continuously without requiring the patient to hold their breath, thus maintaining both accuracy and efficiency.
2Measurement precision
If breath-holding techniques are used during radiotherapy, then targeting accuracy improves, but patient compliance and treatment reproducibility worsen due to difficulty in maintaining consistent breath-holding
Solution Approach 1:
The system provides real-time visual feedback to the patient through a user interface that displays the current breathing phase. This feedback enables the patient to consciously control and reproduce their breathing pattern, making it easier to maintain consistent breathing phases across multiple treatment sessions without requiring difficult breath-holding maneuvers.
Solution Approach 2:
The system utilizes the periodic nature of normal breathing cycles rather than requiring irregular breath-holding. By synchronizing radiotherapy delivery with specific phases of the regular breathing cycle, the system achieves high targeting accuracy while relying on the natural reproducibility of normal breathing patterns, which are easier for patients to maintain consistently.
3Measurement precision
If 4D MRI is used for imaging with long scan times, then soft tissue contrast improves, but scan time increases and patient motion consistency worsens
Solution Approach 1:
The system performs preliminary synchronization of the 4D MRI scan with the patient's breathing pattern before the actual imaging begins. By pre-establishing the breathing phase reference and synchronizing the imaging timing accordingly, the system can acquire high-contrast MRI images during a shorter, synchronized time window, reducing overall scan time while maintaining image quality and motion consistency.
Data Source
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AI summary
Disclosed is a medical system (100, 500) that comprises a radiotherapy system (102) configured for controllably irradiating a target volume (114) within an irradiation zone (112); a subject support (120) configured for supporting at least a ventral region (124) of a subject (122) within the irradiation zone; a breath monitor system (132, 132') configured for providing a motion signal (154, 158) descriptive of subject breathing motion; and a subject display (130, 130') configured for displaying a breathing phase indicator (160, 160') to the subject when supported by the subject support. Execution of the machine executable instructions (150) causes a processor (142) controlling the medical system to receive (200) a time resolved magnetic resonance imaging dataset (152) synchronized to a measured motion signal (154). Execution of the machine executable instructions further causes the processor to repeatedly: determine (202) a desired motion signal (156) by temporally stepping through the measured motion signal; acquire (204) a current motion signal (158) using the breath monitor system; render (206) the breathing phase indicator on the display, wherein the breathing phase indicator is configured to indicate a difference (700) between the desired motion signal and the measured motion signal; and generate (208) control commands (162) configured for controlling targeting of the radio therapy system using a first portion of the time resolved magnetic resonance imaging dataset synchronized to the desired motion signal or a second portion of the time resolved magnetic resonance imaging dataset referenced by the current motion signal.