Multileaf Collimator Aperture for Stereotactic Radiosurgery
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Solution Overview
Problem
Conventional multileaf collimators (MLCs) face challenges in delivering precise radiation beams for stereotactic radiosurgery due to the 'virtual cone' approach, which requires double passes and may compromise beam shape and delivery efficiency, leading to concerns about robustness and accuracy.
Innovation Solution
A multileaf collimator design featuring beam-blocking leaves arranged in multiple levels with through-holes and specific tip profiles to form apertures that allow for direct delivery of cone-like radiation profiles, eliminating the need for double passes and enhancing precision and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SRS cones are mounted externally to a linear accelerator, then radiation delivery is enabled, but collision hazards with treatment couch or patient occur and treatment delivery efficiency is compromised
Solution Approach 1:
The SRS cone functionality is nested within the treatment head by integrating it with the multileaf collimator system. The MLC leaves are configured to form a conical aperture when closed, eliminating the need for separate external cones and their associated mounting mechanisms. This nested integration removes collision hazards while maintaining treatment delivery capability.
2Adaptability or versatility
If the virtual cone approach using MLC is used, then SRS treatment is enabled, but double passes per couch angle are required and beam shape accuracy is compromised
Solution Approach 1:
The MLC leaves are dynamically positioned to form a conical aperture that maintains its shape throughout the treatment delivery. By configuring the leaf tip profiles with specific geometries (e.g., rounded or beveled edges), the system dynamically creates a stable conical beam profile without requiring multiple passes, thereby maintaining beam shape accuracy while enabling SRS treatment.
3Productivity
If MLC leaves are configured to form conical apertures for SRS, then direct radiation delivery is enabled, but the general MLC leaf shape designed for other purposes is compromised
Solution Approach 1:
The MLC leaf design incorporates local quality variations where specific regions of the leaves have different geometries. The tip portions are shaped with rounded or beveled profiles to form conical apertures when closed, while the main body of the leaves retains the standard rectangular shape optimized for general radiotherapy applications. This localized differentiation allows the MLC to perform both SRS and conventional treatments effectively.
Data Source
AI summary
An apparatus includes a first multileaf collimator comprising a plurality of pairs of beam-blocking leaves each comprising an end portion. The end portions of beam-blocking leaves of two adjacent pairs are configured to collectively form an aperture when the two adjacent pairs of beam-blocking leaves are closed. The aperture may be sized and shaped to allow a radiation beam to pass through for radiosurgery.