VMAT Couch Rotation with Cone Beam Imaging
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Solution Overview
Problem
Current VMAT systems are limited in dynamically controlling machine parameters during treatment delivery, leading to increased irradiation of healthy tissues like the lungs, heart, and contralateral breast during breast cancer treatment, and lack real-time treatment verification capabilities.
Innovation Solution
A radiation therapy system with continuous arc rotation and shift of the couch, combined with simultaneous kV cone-beam imaging, dynamically controls table motion, radiation source motion, fluence output rate, and multi-leaf collimator orientation and shape, allowing for real-time adaptation and reduced irradiation to healthy tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VMAT delivers continuous arc therapy with dynamic MLC and dose rate adjustment, then treatment time is reduced and target coverage is improved, but healthy tissues receive increased low-dose irradiation
Solution Approach 1:
The patent introduces continuous couch rotation/shift during VMAT delivery, adding a dynamic degree of freedom to the treatment system. This enables real-time adjustment of patient positioning relative to the radiation source, allowing the treatment plan to adapt continuously during delivery and reduce low-dose exposure to healthy tissues while maintaining target coverage.
Solution Approach 2:
The system dynamically modifies multiple parameters simultaneously including couch position, gantry angle, MLC leaf positions, and dose rate. By continuously adjusting these parameters during treatment delivery, the system optimizes the dose distribution in real-time, reducing integral dose to healthy tissues while maintaining productivity benefits of arc therapy.
2Device complexity
If VMAT uses fixed machine parameters during treatment delivery, then system complexity is reduced, but adaptability to real-time anatomical variations is limited
Solution Approach 1:
The patent implements simultaneous kV cone-beam imaging during VMAT delivery, providing real-time feedback on patient anatomy and position. This feedback is integrated with the treatment delivery system, enabling closed-loop control where imaging data continuously informs adjustments to couch position, gantry angle, and MLC configuration, enhancing adaptability without overwhelming system complexity.
Solution Approach 2:
The treatment system is designed to perform multiple functions simultaneously: therapeutic radiation delivery, real-time imaging, and dynamic parameter adjustment all occur during a single continuous arc rotation. This multi-functionality allows the system to adapt to real-time variations while maintaining a unified control architecture that manages complexity.
3Productivity
If VMAT delivers full dose in single gantry arc with continuous rotation, then treatment efficiency is improved, but precision in controlling beam orientation and intensity is reduced
Solution Approach 1:
The patent segments the control of treatment parameters into multiple independently controllable components: couch rotation, gantry rotation, MLC leaf pairs, and dose rate. Each component can be adjusted with high precision independently, allowing the system to maintain beam orientation and intensity control accuracy even during continuous rapid rotation, thereby preserving both efficiency and precision.
Solution Approach 2:
By making all major parameters dynamic rather than fixed, the system can continuously optimize beam orientation and intensity during the single arc rotation. The continuous adjustment capability maintains precision throughout the dynamic delivery process, preventing the trade-off between speed and accuracy that would exist with pre-programmed fixed parameters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the volume of healthy tissues receiving low-dose irradiation, decreases the risk of toxicity and secondary malignancies, and prescribes fewer monitor units while maintaining target coverage, offering improved conformality and shorter treatment times.
Implementation Method 1
simultaneous kV cone-beam imaging
Data Source
AI summary
A system for radiotherapy that includes a couch upon which a patient being treated by the system is positioned, the couch having continuous arc rotation for delivery accelerated irradiation to the patient.