Gantry Rotation Speed and Dose Rate Control for Respiratory Synchronization
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Solution Overview
Problem
Current radiation therapy methods, such as VMAT and particle arc therapy, face challenges in managing organs with respiratory motion, leading to increased radiation exposure to normal tissues and difficulties in accurately delivering targeted doses due to unpredictable tumor movement and respiratory phase synchronization.
Innovation Solution
A radiation therapy apparatus that monitors the patient's respiration and adjusts the dose rate and gantry rotation speed in real-time to ensure accurate delivery of the target dose during gate irradiation, minimizing exposure to normal tissues and maintaining treatment efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gate irradiation is performed by rotating the gantry only during the irradiation period, then radiation exposure to normal tissue is reduced, but the rotation speed must slow down significantly and the gantry must stop immediately, resulting in increased treatment time
Solution Approach 1:
The gantry rotates during the pause period between adjacent irradiation periods to a predetermined angle, preparing for the next irradiation period. This preliminary action allows the gantry to be already in position when the next irradiation starts, eliminating the need to slow down and stop immediately, thus reducing treatment time while maintaining low radiation exposure to normal tissue
Solution Approach 2:
The rotation speed of the gantry is dynamically adjusted based on the treatment phase: high speed during pause periods for efficient positioning, and controlled speed during irradiation periods for precise dose delivery. This dynamic control resolves the contradiction between rapid movement and precise positioning requirements
2Productivity
If the gantry rotates at high speed during gate irradiation, then treatment throughput is improved, but the administration dose cannot be stabilized and may deviate from the target dose
Solution Approach 1:
The control unit continuously monitors the actual administration dose during gantry rotation and compares it with the target dose. Based on this feedback, the control unit dynamically adjusts the dose rate to stabilize the actual dose at the target level, ensuring precision while maintaining high rotation speed for throughput
Solution Approach 2:
The dose rate parameter is dynamically changed during gantry rotation based on real-time dose monitoring. When the rotation speed is high, the dose rate is adjusted to compensate and maintain stable administration dose, resolving the contradiction between high throughput and dose precision
3Manufacturing precision
If the gantry rotates at low speed during gate irradiation to stabilize administration dose, then dose precision is improved, but treatment throughput decreases
Solution Approach 1:
The feedback control system continuously monitors and adjusts the dose rate based on actual administration dose, allowing the gantry to rotate at high speed while maintaining dose precision through real-time compensation, thus achieving both high throughput and high precision
Solution Approach 2:
The dose rate parameter is dynamically adjusted during high-speed gantry rotation to maintain stable administration dose. This parameter change allows the system to operate at high speed without sacrificing dose precision, resolving the contradiction between throughput and precision
Data Source
AI summary
A radiation therapy apparatus of an embodiment allows radiation to be applied while rotating a gantry and controls irradiation and stop of the radiation during the rotation of the gantry based on respiration of a treatment subject, and includes processing circuitry. The processing circuitry detects the respiration of the treatment subject. The processing circuitry predicts an administration dose based on a respiratory phase range in which the radiation is applied in the respiration of the treatment subject, and changes at least one or both of a dose rate of the radiation to be applied to the treatment subject and a rotation speed of the gantry so that the administration dose reaches a target dose. The processing circuitry performs control according to the change with respect to at least one or both of the dose rate of the radiation and the rotation speed of the gantry.