Inverse Planning Using Multiple RBE Models for Proton Therapy
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Solution Overview
Problem
Current radiation therapy methods for non-photon treatments, such as proton or ion therapy, often rely on single relative biological effectiveness (RBE) models, which can be inadequate for complex treatment planning, particularly in varying tissue depths and doses, leading to suboptimal treatment plans and underestimation of doses at the distal end of proton fields.
Innovation Solution
A method and system for generating non-photon radiation treatment plans using multiple RBE models, allowing for optimization of treatment goals specified in terms of different RBE factors applied to various volumes within or separate from the target volume, enabling more precise and flexible radiotherapy planning by incorporating variable RBE factors and sophisticated models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single RBE model is used for treatment planning, then the planning process is simple and clinically familiar, but the treatment precision is insufficient particularly at distal ends of proton fields
Solution Approach 1:
The patent divides the treatment planning process into multiple segments by applying different RBE models to different anatomical regions or target volumes. Specifically, it uses a first RBE model for the target volume and a second RBE model for organs at risk or other volumes, allowing precise dose calculation in each region without requiring a single complex model for the entire treatment plan.
Solution Approach 2:
The patent applies the principle of local quality by using different RBE models in different spatial locations within the treatment field. The first RBE model is applied to the target volume where tumor control is prioritized, while the second RBE model is applied to surrounding tissues or organs at risk where minimizing side effects is critical. This location-specific approach improves dose measurement precision where it matters most.
2Reliability
If multiple RBE models are used for treatment planning, then treatment precision and tumor coverage are improved, but the planning process becomes more complex
Solution Approach 1:
The patent segments the application of RBE models by associating different models with different target volumes or anatomical regions. This segmentation allows the system to incorporate multiple RBE models for improved reliability without requiring the entire planning system to handle all models simultaneously, thereby managing complexity through structured division of computational tasks.
Solution Approach 2:
The patent creates a universal treatment planning framework that can accommodate multiple RBE models through a common optimization process. The system is designed to accept different RBE models as interchangeable components, allowing the same planning infrastructure to handle various model types depending on the clinical scenario, thus improving reliability without proportionally increasing system complexity.
3Manufacturing precision
If variable RBE factors are applied to different volumes, then dose optimization is improved, but the computational complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the dose optimization process into separate optimization problems for different target volumes, each with its own RBE model. This allows variable RBE factors to be applied to different volumes with improved dose distribution precision, while the segmentation of the optimization process prevents the computational complexity from becoming unmanageable by solving smaller, focused problems rather than one large complex problem.
Data Source
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AI summary
An inverse-planning method (100), by which a treatment plan specifying a non-photon irradiation of a patient including a target volume is generated, comprises: obtaining (110, 112) first and second plan goals in terms of a respective first and second numerical condition on the treatment plan's photon-equivalent dose as computed using a first and second RBE factor; and generating (114) the treatment plan by an optimization process aiming to satisfy the first, second and any further plan goals, wherein (a) the first and second plan goals apply to volumes which either are included in the TV or are completely or partially separate from the TV and/or (b) the first and second RBE factors are variable. In a further aspect, a data carrier provides a treatment plan with these characteristics together with reporting quantities relating to fulfilment of the first and second plan goals.