Particle Beam Scanning Route Optimization Using Tissue-Weighted Evaluation
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Solution Overview
Problem
Current particle beam therapy systems face challenges in optimizing scanning routes to minimize scanning time and avoid irradiation of normal tissue and important organs, as existing methods prioritize route distance over time and do not adequately consider the complexity of non-convex irradiation regions and the risk of irradiating areas outside the target region.
Innovation Solution
A treatment planning device that determines scanning routes for particle beam therapy systems using an evaluation function that weights scanning time and tissue type, specifically using X-directional and Y-directional scanning electromagnets to minimize time and risk of irradiation to normal tissue and important organs, by extracting candidate routes and calculating an evaluation function J that prioritizes affected tissue and penalizes normal tissue and important organs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the scanning route is optimized to minimize route distance, then the scanning time is reduced, but the irradiation risk to normal tissue and important organs increases
Solution Approach 1:
The patent changes the evaluation parameter from单纯的route distance to a comprehensive evaluation function that includes both scanning time and irradiation risk. The evaluation function J = Σ(Tk × wk) transforms the optimization criterion by introducing weight coefficients wk that reflect the irradiation risk of different tissue types, allowing the system to balance speed and safety simultaneously
Solution Approach 2:
The patent implements feedback by using the evaluation function to guide route optimization. The system calculates the evaluation value for different scanning routes and selects the route with the minimum evaluation value, creating a feedback loop that continuously optimizes the scanning route based on both time and safety considerations
2Productivity
If the scanning route prioritizes speed over safety, then productivity increases, but the reliability of treatment decreases
Solution Approach 1:
The patent transforms the optimization parameter from a single-dimensional speed metric to a multi-dimensional evaluation function that incorporates both productivity (scanning time Tk) and reliability (irradiation risk weights wk). This allows the system to achieve high productivity while maintaining treatment safety through mathematical optimization
Solution Approach 2:
The patent introduces dynamic weighting coefficients wk that can be adjusted based on the specific treatment case and tissue sensitivity. This dynamic parameter adjustment allows the system to adaptively balance productivity and reliability for different clinical scenarios, making the optimization flexible and clinically relevant
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
The solution reduces the scanning time and minimizes the risk of irradiation to normal tissue and important organs, providing a more efficient and safer particle beam therapy system.
Implementation Method 1
an X-directional scanning electromagnet and a Y-directional scanning electromagnet for deflecting a charged particle beam in an X-direction and a Y-direction
Implementation Method 2
a particle beam has the feature such that the absorbed dose reaches a peak just before when the particle beam stops. Therefore, by changing a level of energy, a position where the absorbed dose reaches a peak (will be referred as a Bragg peak) can be focused on cancer nidus
Data Source
AI summary
A scanning candidate route extracting unit which extracts plural candidates of scanning routes in which each of the scanning routes connects all spot positions in one layer is provided, in an evaluation function using necessary scanning time Tk and weight coefficient wk for a kth partial route among partial routes which are routes between the spot positions which are adjacent on one of the plural candidates of scanning routes, and number n of spot in the layer, wk with respect to a partial route which passes through affected tissue is set to be 1, wk with respect to a partial route which passes through normal tissue is set to be bigger than 1, and wk with respect to a partial route which passes through an important internal organ is set to be bigger than wk with respect to a partial route which passes through normal tissue.