Crystalline Structure Modeling for Conformal Radiation Spot Placement
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Solution Overview
Problem
Existing radiation therapy techniques struggle to precisely place spots for spot scanning to conform to treatment targets while minimizing exposure to healthy tissue and avoiding dose variations, particularly in high-dose rate therapies like FLASH radiation therapy.
Innovation Solution
Utilizing crystalline structure modeling, specifically phase-field crystal (PFC) modeling, to iteratively relax density fields and determine optimal spot locations that conform to treatment target outlines and ensure uniform dose distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed (raster) pattern is used for spot placement, then the scanning path is simple and easy to implement, but the spot placement does not conform well to the treatment target outline, resulting in poor lateral penumbra and exposure of healthy tissue
Solution Approach 1:
The patent applies preliminary action by pre-calculating optimal spot positions using crystalline structure modeling before radiation delivery. The density field is relaxed iteratively to determine peak locations that conform to the treatment target outline, and these pre-determined spots are then used during scanning, eliminating the need for complex real-time adjustments while maintaining conformity.
Solution Approach 2:
The patent changes the parameter of spot placement from fixed raster coordinates to dynamically optimized positions based on crystalline structure modeling. By varying the density field parameters and relaxing them to equilibrium, the system generates spot positions that adapt to the treatment target geometry, improving lateral penumbra while keeping the scanning path relatively simple.
2Manufacturing precision
If spots are placed to conform to the target outline, then lateral penumbra is improved and healthy tissue is spared, but dose uniformity inside the target may deteriorate
Solution Approach 1:
The patent uses parameter changes by adjusting the density field parameters during iterative relaxation. The chemical potential and other thermodynamic parameters are modified to ensure that the resulting peak positions satisfy both boundary conformity and interior uniformity requirements, achieving a balanced spot distribution.
Solution Approach 2:
The patent implements feedback through iterative relaxation of the density field. Each iteration provides feedback on the current spot distribution, and the system adjusts the density field accordingly to improve both conformity and uniformity. The process continues until convergence criteria are met, ensuring optimal balance between the two objectives.
3Device complexity
If conventional spot placement methods are used, then the treatment planning is simpler, but the scanning time is longer and dose uniformity is poorer
Solution Approach 1:
The patent applies preliminary action by performing comprehensive spot optimization using crystalline structure modeling during the treatment planning phase. This pre-optimization determines the optimal spot positions that maximize dose uniformity and minimize scanning time, allowing the actual treatment delivery to proceed efficiently without requiring complex real-time adjustments.
Solution Approach 2:
The patent substitutes mechanical trial-and-error optimization with a physics-based crystalline structure modeling approach. Instead of using conventional iterative algorithms that mechanically adjust spot positions, the system uses thermodynamic relaxation of density fields to naturally evolve toward optimal configurations, reducing computational complexity and improving efficiency.
Data Source
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AI summary
A crystalline structure modeling methodology that is conventionally used to model crystalline matter down to the atomic level is instead used to determine spot placement for radiation treatment. The cross-sectional shape of a treatment target is specified 202; locations (peaks) in a density field inside the shape are determined using the crystalline structure model 204; locations of spots in the treatment target for spot scanning are determined 206, where the locations correspond to the locations (peaks) inside the shape determined using the crystalline structure model; and the locations of the spots are stored as candidates for potential inclusion in a radiation treatment plan 208.