Radiotherapy Control Apparatus Swing Position Correction
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Solution Overview
Problem
Radiotherapy systems face challenges in maintaining high accuracy and stability when moving therapeutic radiation units to ensure precise irradiation, particularly during patient breathing movements, which can lead to motor trips and reduced therapy effectiveness.
Innovation Solution
A control apparatus that calculates a post-correction target position based on the position of a specific patient part, using a swing position control section to gradually adjust the radiation irradiating unit's position, incorporating an operation amount calculation, coefficient adjustment, feed-forward operation, and temperature drift correction to prevent motor trips and enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the radiation irradiating unit moves quickly to track patient breathing movements, then the therapy effectiveness is improved, but motor trips occur and movement accuracy decreases
Solution Approach 1:
The control apparatus dynamically adjusts the movement characteristics of the radiation irradiating unit based on real-time position feedback. The swing position control section modifies the drive commands to account for the mechanical dynamics of the positioning system, ensuring smooth acceleration and deceleration that prevents motor trips while maintaining tracking accuracy during patient breathing movements.
Solution Approach 2:
The system implements a feedback mechanism where the actual position of the radiation irradiating unit is continuously monitored and compared with the target position calculated from patient anatomy data. The swing position control section uses this position feedback to generate corrected drive commands, creating a closed-loop control system that maintains accuracy without requiring aggressive speed adjustments that would cause motor trips.
2Measurement precision
If the drive unit operates with high responsiveness to track moving targets, then the therapy precision is improved, but motor trips occur reducing system stability
Solution Approach 1:
The swing position control section incorporates dynamic compensation that adjusts the drive unit's responsiveness based on the current operating state. By modeling the mechanical system's dynamics, the control apparatus can apply appropriate gain scheduling that maintains high precision during stable operation while preventing excessive responsiveness that would trigger motor trips during transient movements.
Solution Approach 2:
The system applies preliminary anti-action by predicting potential motor trip conditions based on the calculated swing position and preventing them before they occur. The control apparatus pre-adjusts drive commands to avoid commanding movements that would exceed motor operational limits, thereby maintaining both precision and stability without requiring reactive corrections after motor trips occur.
Data Source
AI summary
A control apparatus of a radiotherapy system of the present invention includes an irradiation object detecting section configured to calculate a target position based on a position of a specific part of a sample; and a swing position control section configured to control a drive unit to drive a radiation irradiating unit which irradiates a therapeutic radiation, such that the radiation irradiating unit directs to a post-correction target position at a control time after the measurement time. The post-correction target position indicates a position near a position to which the radiation irradiating unit directs rather than the target position in the preparation period before a therapy period, and the target position in the therapy period.