High-Speed MLC for Independent 2D Sub-Beam Intensity Patterns
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Solution Overview
Problem
Conventional multileaf collimators (MLCs) in radiation treatment systems are limited in conforming radiation beam fields to target regions along their length, especially for non-uniform shapes, leading to excessive radiation exposure to non-target areas and restricted field sizes due to slow leaf motion and constant field sizes.
Innovation Solution
The implementation of a high-speed multileaf collimator (MLC) that enables rapid leaf motion, allowing for larger field sizes and intensity modulation in both the IEC-Xb and IEC-Yb directions, along with longitudinal modulation, to precisely shape the radiation beam and minimize exposure to non-target regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional MLC with slow leaf motion is used, then radiation beam can be shaped to target region, but field size is restricted and treatment time is prolonged
Solution Approach 1:
The patent implements a high-speed MLC system where leaves can move dynamically at accelerated speeds (up to 5 cm/s or higher) compared to conventional MLCs. This enables the system to rapidly adjust aperture shapes and field sizes during treatment, allowing larger field sizes to be delivered without extending treatment time, directly resolving the contradiction between leaf motion speed and treatment time.
2Adaptability or versatility
If conventional MLC with constant field size is used, then radiation beam aperture can be defined, but field size cannot be varied and exposure to non-target areas increases
Solution Approach 1:
The high-speed MLC enables dynamic variation of field sizes during treatment delivery. The system can adjust aperture shapes and dimensions in real-time to match the target region geometry, varying field sizes as needed without mechanical constraints. This adaptability allows precise conformal radiation therapy that minimizes exposure to non-target areas while treating targets of various sizes and shapes.
3Manufacturing precision
If conventional MLC is used for non-uniform target shapes, then radiation beam can be shaped, but conformity to target region is insufficient leading to excessive radiation to non-target regions
Solution Approach 1:
The MLC system divides the radiation field into multiple independently controllable segments (leaf pairs), each capable of independent motion and positioning. This segmentation allows the aperture shape to be precisely customized to match complex non-uniform target geometries, creating conformal radiation fields that closely follow the target boundaries and minimize dose to surrounding healthy tissues.
Solution Approach 2:
The high-speed MLC enables dynamic adjustment of aperture shapes during treatment delivery, allowing the beam conformation to adapt in real-time to the target region geometry. This dynamic capability enhances the precision of beam conformation for non-uniform targets, improving the ability to deliver radiation selectively to the target while sparing non-target areas.
Data Source
AI summary
A radiation delivery system and method of operation are described. The method includes modulating a sub-beam intensity of a radiation beam generated by a radiation source across a plurality of sub-beams that subdivide a fluence field into a two-dimensional (2D) grid, and delivering a plurality of independent two-dimensional (2D) sub-beam intensity patterns from a plurality of angles while the radiation source is moved continuously.