IGRT Ventilator Closed-Loop for Respiratory Motion Control
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Solution Overview
Problem
Current radiation therapies struggle to effectively manage respiratory motion during treatment, leading to artifacts in imaging and increased exposure of healthy tissues due to the inability to stabilize tumor position, particularly in patients with compromised pulmonary function who cannot comply with existing breath-hold techniques.
Innovation Solution
A closed-loop system combining image-guided radiation therapy (IGRT) with a medical ventilator for controlled respiratory-gating and selective lung ventilation, allowing for precise anatomical positioning and synchronization of the respiratory cycle to optimize tumor targeting and minimize exposure to healthy tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If margins are allocated to cover tumor motion due to respiration, then adequate coverage of the tumor is ensured, but the radiation field size increases and exposes healthy tissue to high doses of radiation
Solution Approach 1:
The system dynamically adjusts the radiation beam's operational state (on/off) based on real-time respiratory phase detection. The ventilator synchronizes breath-hold maneuvers with beam delivery, allowing the treatment system to adapt to respiratory motion rather than using static margins. This dynamic approach ensures tumor coverage only when the tumor is in the correct position, eliminating the need for expanded margins that would otherwise protect against motion.
2Reliability
If Deep Inspiration Breath Hold (DIBH) or Active Breathing Control (ABC) techniques are used, then respiratory motion is stabilized and tumor position is fixed, but these techniques are only applicable to alert, oriented, cooperative patients who can understand coaching instructions
Solution Approach 1:
The system uses automated ventilator control to perform breath-hold maneuvers without requiring patient cooperation or understanding. The ventilator independently manages respiratory control, eliminating the need for patient coaching while achieving the same tumor stabilization效果. This self-service approach extends the applicability of breath-hold techniques to patients who cannot comply with manual coaching instructions.
Solution Approach 2:
The invention replaces the manual coaching and voluntary breath-hold mechanism with an automated mechanical ventilator system. The ventilator uses mechanical control to achieve precise breath-hold positioning, substituting the need for patient cognitive engagement and voluntary control. This mechanical substitution enables breath-hold techniques to be used with patients who lack the cognitive or physical capacity for manual techniques.
3Productivity
If conventional radiotherapy techniques are used without considering respiratory motion during image acquisition, then the imaging process is simple and quick, but artifacts are created that distort the target volume and provide incorrect positional information
Solution Approach 1:
The system performs preliminary respiratory synchronization by coordinating the imaging process with the ventilator-controlled respiratory cycle. Images are acquired during specific respiratory phases (typically end-expiration or breath-hold) when the tumor is in a known, stable position. This preliminary timing action prevents motion artifacts before they occur, ensuring accurate target visualization without requiring complex post-processing or significantly extending acquisition time.
Data Source
AI summary
The system and method of the present application includes an image guided radiation therapy (IGRT) system, combined with a medical ventilator, to form a closed-loop system to optimize treatment of a tumor for patients who cannot comply with a normal respiratory management procedure. The ventilator may be used to generate respiratory maneuvers to facilitate clean images for dose planning, so that clinicians can more clearly visualize a target with fewer of the image artifacts associated with respiratory motion. The combined IGRT and ventilation systems approach facilitates treatment of specific organs most susceptible to respiratory motion artifact, and helps minimize the doses to the heart in left-breast treatments. Improved positioning of the anatomical target structures for exposure to external beam radiation may be accomplished through combinations of respiratory-gating, respiratory pause, and selective right or left lung mechanical ventilator techniques.