Achromatic Medical Gantry Beam Transport
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Solution Overview
Problem
Existing particle beam therapy systems face challenges in maintaining high-precision beam delivery independent of gantry rotation, often requiring additional equipment or leading to beam intensity loss and increased treatment time due to non-symmetric ion beams and the need for collimators or rotators.
Innovation Solution
A medical particle therapy gantry design featuring a combination of dipole and quadrupole magnets that maintains an achromatic and linearly uncoupled beam path, allowing for precise beam focusing and delivery independent of gantry rotation, using a configuration of sector bends and strategically placed quadrupoles to control beam size and shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional gantry arrangement with dipole and quadrupole magnets is used to deliver ion beams at different angles, then the beam can be directed to patients from multiple directions, but the beam transport becomes dependent on gantry rotation angle, resulting in varying beam precision from different directions
Solution Approach 1:
The patent applies asymmetry by using a non-symmetric ion beam configuration with different emittances in vertical and horizontal planes, combined with an achromatic beam transport system that compensates for rotation-dependent effects. The beam line is designed with specific optical properties that maintain constant beam characteristics regardless of gantry rotation angle, resolving the contradiction between directional flexibility and beam precision.
Solution Approach 2:
The patent changes the optical parameters of the beam transport system by designing an achromatic system where the transfer matrix elements are independent of gantry rotation angle. This is achieved by carefully selecting quadrupole magnet strengths and positions to compensate for rotation-induced changes, maintaining constant beam spot size and shape across all rotation angles.
2Manufacturing precision
If collimators are added to narrow the beam and filter particles, then beam precision can be improved, but significant beam intensity loss occurs and continuous beam tuning is required
Solution Approach 1:
The patent extracts the beam narrowing function from mechanical collimators and replaces it with magnetic focusing elements (quadrupole magnets). The quadrupoles provide continuous beam confinement and shaping without the intensity loss associated with physical collimation, eliminating the need for continuous beam tuning while maintaining precision.
Solution Approach 2:
The patent substitutes the mechanical collimation system with a magnetic beam transport and focusing system. Instead of using physical collimators to filter particles, the system uses achromatic beam transport with quadrupole magnets to maintain beam precision through magnetic focusing, avoiding the intensity loss and tuning requirements of mechanical collimation.
3Manufacturing precision
If a rotator section is added to synchronously rotate with the gantry, then beam independence from gantry rotation can be achieved, but about 10 m of extra transfer line length is required and additional precise mechanical rotation equipment is needed
Solution Approach 1:
The patent merges the beam transport and focusing functions into a single integrated achromatic beam line design. Instead of adding a separate rotator section, the quadrupole magnets are strategically positioned within the existing gantry structure to provide both transport and focusing while maintaining achromaticity, eliminating the need for additional mechanical rotation equipment and reducing overall system complexity.
Solution Approach 2:
The patent makes the quadrupole magnets serve multiple functions: they provide both beam transport and focusing while simultaneously maintaining achromatic beam transport independent of gantry rotation. This multi-functionality eliminates the need for separate rotator equipment and reduces the overall system complexity while achieving beam rotation independence.
4Manufacturing precision
If the beam line is designed to be achromatic and uncoupled, then beam precision is maintained independent of gantry rotation, but the non-symmetric beam requires careful optical matching
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-configuring the quadrupole magnet strengths and positions to achieve the desired achromatic and uncoupled beam transport. The optical matching is performed during the design phase, allowing the system to maintain beam precision independence from gantry rotation without requiring complex real-time adjustments during operation.
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 design ensures a stable, high-precision beam spot at the patient regardless of gantry orientation, eliminating the need for collimators or rotators, thus maintaining beam intensity and reducing treatment time, while being compact enough for hospital facilities.
Implementation Method 1
a plurality of dipole magnets that bend the trajectory of the beam path onto a patient
Implementation Method 2
a plurality of quadrupole magnets that focus the beam and maintain a small, high-precision beam spot at the patient by creating an achromatic and linearly uncoupled conditions
Data Source
AI summary
A medical gantry that focus the beam from the beginning of the gantry to the exit of the gantry independent of the rotation angle of the gantry by keeping the beam achromatic and uncoupled, thus, avoiding the use of collimators or rotators, or additional equipment to control the beam divergence, which may cause beam intensity loss or additional time in irradiation of the patient, or disadvantageously increase the overall gantry size inapplicable for the use in the medical treatment facility.