Passive Ion Beam Arc Therapy via Couch Rotation
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Solution Overview
Problem
Current ion-based radiotherapy systems face challenges in delivering arc therapy efficiently due to the need for expensive and space-consuming gantries, which hinder the ability to rotate beams quickly enough for high-quality arc therapy, especially in passive ion therapy where the beam must be precisely controlled to target tumors while sparing organs at risk.
Innovation Solution
A method and system for generating a radiotherapy plan that allows variation in settings of passive devices such as range modulating devices and aperture elements during beam delivery, enabling continuous or sub-arc movements to optimize beam shape and depth, allowing for faster and more precise ion beam delivery, including the use of optimization techniques to control the movement of the patient or beam to create an arc therapy plan that conforms closely to the target while sparing organs at risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rotating gantry is used for ion-based arc therapy, then beam delivery flexibility and dose distribution are improved, but system cost and space requirements increase significantly
Solution Approach 1:
Instead of rotating the heavy gantry to deliver the beam from different angles, the patent inverts the approach by keeping the gantry fixed and rotating the patient support structure (couch) to achieve the same arc therapy effect. This reduces the mechanical complexity and cost while maintaining beam delivery flexibility.
Solution Approach 2:
The patent extracts the rotation function from the gantry system and transfers it to the patient support structure. This separates the beam delivery system from the positioning system, allowing the gantry to remain simple and fixed while the couch handles the arc motion.
2Productivity
If gantry rotation speed is increased to deliver arc therapy in acceptable time, then treatment efficiency is improved, but mechanical stress and system complexity increase
Solution Approach 1:
The patent transfers the high-speed rotation requirement from the gantry to the patient support couch. Since the couch is designed for patient positioning anyway, adding rotation capability is more feasible and less mechanically complex than making the entire gantry rotate at high speeds.
3Manufacturing precision
If passive devices are used to shape the ion beam, then dose precision is improved, but the ability to adapt to organ motion and complex target shapes is limited
Solution Approach 1:
The patent introduces dynamic elements to the passive beam shaping approach by allowing the settings of passive devices (aperture, range modulator, compensator) to vary continuously during beam delivery. This enables the beam shape and energy distribution to adapt in real-time to organ motion and complex target geometries while maintaining the precision benefits of passive shaping.
Solution Approach 2:
The patent uses pre-calculated optimal settings for passive devices at different angles along the arc, which are determined through treatment planning before delivery. During treatment, these pre-determined settings are executed, allowing the system to adapt to complex targets while maintaining precision.
4Ease of manufacture
If forward planning is used to create treatment settings, then treatment planning simplicity is maintained, but optimization of dose distribution and organ protection is insufficient
Solution Approach 1:
The patent performs comprehensive treatment planning and optimization before beam delivery, calculating the optimal settings for passive devices at multiple angles along the arc. This preliminary optimization ensures excellent dose distribution and organ protection, while the actual delivery remains relatively simple by executing the pre-planned settings.
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 enables more robust and efficient delivery of ion-based arc therapy, reducing treatment time and improving dose uniformity, with the ability to create flexible and optimized Spread Out Bragg Peak (SOBP) shapes, providing better protection to organs at risk and accommodating organ motion, while being more cost-effective by using a fixed beam line and patient movement rather than a rotating gantry.
Implementation Method 1
an ion will deposit most of its energy close to the depth where it stops, in the area known as the Bragg peak
Implementation Method 2
The lateral shape of the beam is controlled by an aperture in the beam line, such as a block or a collimator of a non-permeable material
Implementation Method 3
The range compensator shortens the local range of the ion beam and is non-uniformly shaped to conform to the distal edge of the tumour
Data Source
Figure 1~2
Figure 3~6
AI summary
A method of generating a radiotherapy plan for ion therapy, wherein the beam (6) is shaped by means of passive devices is arranged to allow variation in settings of at least one of the passive devices and/or the MU during the delivery of the beam and to control the movement of the patient and/or the beam in such a way as to create an arc. The arc is preferably a continuous arc or includes at least one continuous sub-arc. The method may include forward planning or optimization. In the latter case, the optimization uses an optimization problem set up to allow variation in settings of at least one of the range modulating device (9), the aperture element (11) and the MU during the delivery of the arc. Computer programs control the planning and the delivery.