Multi-Layer Multi-Leaf Collimator Aperture Resolution
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Solution Overview
Problem
Multi-leaf collimators face limitations in beam resolution, which can result in radiation beams not perfectly matching treatment requirements, due to the maximum resolution of their leaf dimensions, and existing multi-layer designs do not provide effective methods for designing and administering treatment plans.
Innovation Solution
A multi-layer multi-leaf collimation system where a proximal layer of collimation leaf pairs is vertically offset with respect to a distal layer, forming linearly-sequential high-resolution apertures, and a control circuit modulates the radiation beam to administer a treatment plan using these high-resolution apertures, potentially with multiple radiation exposures to ensure precise dosing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-layer multi-leaf collimator is used, then the device complexity is low, but the aperture resolution is limited by the leaf dimensions
Solution Approach 1:
The patent transitions from a single-layer collimator to a multi-layer collimator configuration, adding the dimension of depth (z-axis) to the traditional two-dimensional leaf arrangement. This allows the system to achieve higher aperture resolution by stacking multiple layers of leaves at different positions along the beam path, effectively creating three-dimensional beam shaping capability that overcomes the resolution limits of individual leaf dimensions.
Solution Approach 2:
The patent implements a nested structure where multiple layers of collimation leaves are positioned within the same spatial envelope, with each layer containing leaf pairs that can independently move. The layers are arranged such that they occupy overlapping but distinct spatial regions along the beam path, allowing compact integration of multiple resolution-enhancing layers without proportionally increasing the overall device footprint.
2Manufacturing precision
If the leaf cross-dimension is reduced to increase resolution, then the aperture resolution improves, but the manufacturing precision and structural integrity become more difficult to maintain
Solution Approach 1:
Instead of using a single large leaf with fine dimensional tolerances, the patent segments the collimation function across multiple layers, each containing leaves with larger, more manufacturable dimensions. The segmentation of the beam-shaping function across layers allows each individual leaf to have relaxed manufacturing tolerances while the collective arrangement of multiple leaves achieves the desired high-resolution aperture definition through their combined geometric configuration.
3Manufacturing precision
If a multi-layer multi-leaf collimator is implemented, then the aperture resolution increases, but the device complexity and treatment planning complexity increase
Solution Approach 1:
The patent implements dynamic control of multiple leaf layers, where each layer's leaves can be independently positioned and adjusted during treatment delivery. This dynamic capability allows the system to adaptively create complex aperture patterns by coordinating the movement of leaves across multiple layers, enabling high-resolution beam shaping that responds to real-time treatment requirements while maintaining manageable system control through programmable automation.
Data Source
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AI summary
A control circuit 201 administers a radiation treatment plan that specifies a planned total radiation dose for a radiation treatment session for a given patient 207 by modulating a radiation beam 203 with at least one high-resolution aperture that is formed using one of a plurality of linearly-sequential high-resolution aperture possibilities. By one approach the foregoing comprises modulating the radiation beam using at least substantially only high-resolution apertures that are formed using a plurality of the linearly-sequential high-resolution aperture possibilities. In some cases the foregoing can comprise administering the radiation treatment plan using at least two separate radiation exposures for only a single treatment field, in which case, by one approach, each of the separate radiation exposures for the single treatment field can comprise modulating the radiation beam using at least substantially only high-resolution apertures.