Ion Therapy Plan Quality via Path Length Spread
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Solution Overview
Problem
Current ion-based radiotherapy treatment plans face challenges in ensuring robustness due to uncertainty factors like CT calibration, tissue inhomogeneity, and organ motion, which affect the accuracy and consistency of dose distribution, particularly in scattering and energy loss of ions within the patient's anatomy.
Innovation Solution
A method to evaluate the quality of ion-based treatment plans by calculating a quality value based on the spread of effective path lengths traversed by ions, using water equivalent path lengths (WEPL) or initial energy, to assess the plan's robustness and heterogeneity within the treatment volume, which can be visually represented for improved planning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ion-based radiotherapy treatment plans are used, then dose distribution can be delivered, but robustness is compromised due to uncertainty factors like CT calibration, tissue inhomogeneity, and organ motion
Solution Approach 1:
The patent applies preliminary action by evaluating treatment plan robustness before actual treatment delivery. It calculates quality values based on path length spread for multiple scenarios (including variations in CT calibration, tissue density, and patient position) in advance, allowing the treatment plan to be optimized and validated before execution, thereby ensuring robustness and accuracy.
Solution Approach 2:
The patent implements feedback by comparing calculated quality values against predefined thresholds or reference values. The system provides feedback information about the robustness of the treatment plan, identifying areas where the dose distribution may be affected by uncertainties, and enabling iterative optimization to achieve the desired robustness level.
2Manufacturing precision
If treatment plans are optimized for specific patient anatomy, then dose distribution accuracy improves, but adaptability to anatomical variations decreases
Solution Approach 1:
The patent applies parameter changes by evaluating the treatment plan under multiple scenarios with varying anatomical parameters (such as different tissue densities, patient positions, and anatomical variations). It calculates quality values based on path length spread for each scenario, allowing the system to assess how the plan performs under different anatomical conditions and optimize it to maintain accuracy across variations.
Solution Approach 2:
The patent implements dynamics by creating a dynamic evaluation framework that assesses treatment plan robustness across multiple possible anatomical configurations. Instead of optimizing for a single static anatomy, the system dynamically evaluates performance across different scenarios, enabling the plan to adapt to anatomical variations while maintaining dose distribution accuracy.
3Reliability
If multiple scenarios are evaluated to assess robustness, then plan quality improves, but computational complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the treatment volume into multiple portions or regions and evaluating path length spread separately for each region. It also segments the evaluation into different scenarios (e.g., different anatomical variations, calibration conditions) and calculates quality values for each scenario independently, making the complex computational task more manageable and systematic.
Solution Approach 2:
The patent uses copying by creating virtual copies of the treatment plan evaluated under multiple scenarios. Instead of physically implementing all possible anatomical variations, the system creates computational copies or representations of different scenarios (using Monte Carlo simulations or analytical models) and evaluates the plan against these copies, reducing the need for complex physical experimentation while maintaining comprehensive assessment.
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
This approach enhances the robustness of ion-based radiotherapy treatment plans by quantifying the spread in path lengths, allowing for better prediction of treatment outcomes under anatomical variations and providing a graphical representation for easier interpretation.
Implementation Method 1
In ion based radiotherapy each ion will emit most of its energy towards the end of its path, creating what is known as the Bragg peak
Implementation Method 2
The effective path length traversed by an ion is a function of the energy of the ion and the density of the matter it traverses
Implementation Method 3
Structural variations in the patient's body will lead to scattering of particles, altering their path and therefore affecting the resulting dose distribution
Data Source
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AI summary
The quality of an ion based treatment plan may be evaluated by evaluating, for each portion of the treatment volume, a quality value based on the spread in a path length value indicative of effective path lengths of ions that stop in that portion and to use this quality value as a measure of the quality of the plan. The quality value may be based on the spread in WEPL or in the initial energy of each ion that stops in the respective portion.