Dynamic Gantry Speed Control for Rotational Radiotherapy
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Solution Overview
Problem
Conventional rotational radiotherapy systems are inefficient and insufficient for treating moving targets, as they often result in increased radiation exposure to healthy tissues due to the need for large margins or auxiliary devices to track target movement.
Innovation Solution
A system that dynamically adjusts the gantry speed and beam shaping to synchronize radiation delivery with the patient's periodic motion, using a predictive model to determine optimal treatment windows and deliver radiation in 'burst modes' to minimize exposure to healthy tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an increased margin of delivery is used around the target to account for target excursions, then the target receives the desired radiation dose, but surrounding healthy tissue or organs are at an increased risk of receiving radiation
Solution Approach 1:
The system dynamically adjusts gantry speed during rotational radiotherapy treatment based on real-time target position feedback. When the target is within the treatment window, the gantry maintains nominal speed; when the target moves outside the window, the gantry speed is reduced or paused. This dynamic speed adjustment allows the radiation beam to track the moving target accurately without requiring an increased delivery margin, thereby protecting surrounding healthy tissue from unnecessary radiation exposure.
Solution Approach 2:
The system employs a feedback mechanism where the actual target position is continuously monitored and compared against the treatment window. Based on this feedback, the gantry speed is adjusted in real-time to ensure the radiation beam remains synchronized with the target position. This closed-loop control enables precise radiation delivery to moving targets while minimizing exposure to healthy tissues, resolving the contradiction between dose accuracy and healthy tissue protection.
2Object-affected harmful factors
If gated treatment techniques are used to deliver radiation only when the patient is within a gating window, then healthy tissue exposure is reduced, but acquisition of planning images and breathing monitoring devices are required
Solution Approach 1:
The system integrates multiple functions into the existing radiotherapy apparatus. The gantry itself serves both as the radiation delivery mechanism and as the motion control mechanism through dynamic speed adjustment. The control system integrates target position monitoring, treatment window evaluation, and gantry speed control into a unified system. This multi-functionality eliminates the need for separate auxiliary tracking devices while maintaining gated treatment capabilities, reducing device complexity while still protecting healthy tissue.
Solution Approach 2:
The radiotherapy system performs its own motion management functions through self-adjustment of gantry speed based on target position feedback. Rather than relying on external auxiliary devices to track and compensate for target motion, the system uses its own gantry motion to adapt to target position changes. This self-service approach reduces the need for additional auxiliary equipment while maintaining the ability to deliver radiation selectively during treatment windows.
3Productivity
If the gantry rotates continuously around the patient, then treatment efficiency is maximized, but the ability to accurately target moving areas is compromised
Solution Approach 1:
The system transitions from static, uniform gantry rotation to dynamic, variable-speed rotation. The gantry speed is continuously adjusted based on real-time target position relative to the treatment window. This dynamic approach allows the gantry to maintain continuous motion for efficiency while temporarily pausing or slowing down when the target moves outside the treatment window, thereby maintaining targeting precision without sacrificing overall treatment efficiency.
Solution Approach 2:
The system maintains continuous gantry rotation to maximize treatment efficiency, but modulates the speed to ensure accurate target delivery. Rather than stopping and starting the gantry completely, the system keeps the gantry in continuous motion at variable speeds, adjusting the rotation rate to match target position. This continuous action with speed modulation preserves both efficiency and precision, allowing the radiation beam to remain synchronized with the moving target throughout the treatment cycle.
Data Source
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AI summary
Some aspects include a system (100), apparatus (100), and method (500) for determining (S51 0) a motion of a patient area due to breathing is substantially periodic according to a treatment plan, moving (S520) a radiotherapy gantry (115) towards a first treatment gantry angle, moving (S520) a radiotherapy beam shaping device (80) towards a first treatment shape corresponding to the first treatment gantry angle, determining (S525) when a next treatment window is to begin based on a predictive model derived from the motion of the patient area, where the treatment window is a period of time designated for delivery of treatment radiation to the patient area according to the treatment plan, adjusting (S530) the moving of the radiotherapy gantry (115) such that the radiotherapy gantry (115) will reach the first treatment angle during the determined next treatment window, and delivering (S540) a treatment radiation beam to the patient area during the determined next treatment window.