Method, a computer program product and a computer system for radiotherapy optimization
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Publication Number
US-10549120-B2
Publication Date
2020-02-04
Expiration Date
Abstract
An interpolation of deliverable radiotherapy treatment plans is facilitated by restricting the movement of the multi-leaf collimator leaves between optimization steps.
Core Innovation
The invention creates an interpolated radiotherapy treatment plan for delivering a radiation beam from a radiotherapy system comprising jaws and a multi-leaf collimator with leaves for shaping the radiation beam. The method provides a first deliverable treatment plan that includes first leaf position settings for a number of leaves of the multi-leaf collimator and, optionally, first jaw position settings, and a second deliverable treatment plan that includes second leaf position settings and, optionally, second jaw position settings.
The second deliverable treatment plan is obtained using constraints that limit differences between the first and second deliverable treatment plans, including a maximum difference in position settings for each leaf and, optionally, a maximum difference in positions of the jaws. An interpolated treatment plan is created based on the first and second deliverable treatment plans, and the interpolated treatment plan controls the radiotherapy system to deliver the radiation beam.
A treatment plan is deliverable when the treatment plan satisfies a predefined objective and no conversion step is required for the treatment plan to be delivered on the radiotherapy system. By constraining maximum movement of multi-leaf collimator leaves, and optionally jaw positions, between deliverable plans, the interpolation is performed in deliverable control parameters while maintaining deliverability and enabling dose recalculation after interpolation for near real-time display.
The described embodiments include sequential reoptimization and interpolation, using multiple preplanned optimization problems with shared leaf and jaw constraints, and simultaneous optimization of multiple plans with constraints. The document additionally describes contextual prior-art contrast and example outcomes comparing constrained and unconstrained interpolation using dose-volume histogram style evaluation and clinical trade-offs using weighted interpolation and navigation across Pareto surfaces.
Claims Coverage
Independent claim clm-00001 defines the overall method for creating an interpolated radiotherapy treatment plan by using deliverable first and second treatment plans whose multi-leaf collimator leaf positions, and optionally jaw positions, are constrained in difference. The independent claim further requires creating an interpolated treatment plan that controls delivery and is deliverable without requiring a conversion step, provided a predefined objective is satisfied. The dependent claims refine how the second and/or additional deliverable treatment plans are created and how constraints relate to deliverability and interpolation.
Creating an interpolated radiotherapy plan from constrained deliverable plans
Providing a first deliverable treatment plan with first leaf position settings and, optionally, first jaw position settings, and providing a second deliverable treatment plan with second leaf position settings and, optionally, second jaw position settings, wherein the second deliverable treatment plan is obtained using a maximum difference in position settings for each leaf between the first and second leaf position settings and optionally a maximum difference in positions of the jaws; creating an interpolated treatment plan based on the first and second deliverable treatment plans so that the interpolated treatment plan controls the radiotherapy system to deliver the radiation beam, with deliverability when the treatment plan satisfies a predefined objective and no conversion step is required.
Constrained generation of the second deliverable treatment plan
The method further specifies that the second deliverable treatment plan is created based on the first deliverable treatment plan.
Interpolation with additional deliverable plans and additional optimization problems
Obtaining an additional treatment plan that includes additional leaf position settings for a number of leaves of the multi-leaf collimator and additional jaw position settings for the jaws, optimizing the additional plan with an additional optimization problem under constraints limiting maximum difference in leaf positions and maximum difference in jaw positions between the plans, and creating an interpolated treatment plan by interpolating between the first, second, and/or additional treatment plans.
Quantitative leaf movement constraint range
Setting the maximum difference in position settings for each leaf to be between 0.01 cm and 2 cm.
Leaf movement constraint tied to fluence resolution
Specifying that the maximum difference in position settings for each leaf corresponds substantially to a fluence resolution.
Computer-system implementation for dose calculations with image registration
A computer system including a processor configured to perform dose calculations in radiotherapy by performing image registration under control of a stored computer program product.
Overall, the claim set covers interpolation between deliverable radiotherapy treatment plans by constraining differences in multi-leaf collimator leaf positions, and optionally jaw positions, between the first and second deliverable plans, then generating an interpolated control-parameter treatment plan that is deliverable without a conversion step when a predefined objective is satisfied. Additional dependent features further specify constrained construction of the second plan, extension to additional deliverable plans and optimization problems, quantitative or fluence-resolution-related leaf-difference constraints, and computer-system implementation for dose calculations with image registration.
Stated Advantages
Maintains deliverability by ensuring the interpolated treatment plan can be delivered without requiring a conversion step when a predefined objective is satisfied.
Constrains maximum movement of multi-leaf collimator leaves, and optionally jaw positions, between first and second deliverable plans to support interpolation directly in deliverable control parameters.
Enables dose recalculation after interpolation for near real-time display.
Supports navigation across clinical trade-offs using weighted interpolation and Pareto surfaces.
Documented Applications
Radiotherapy treatment planning and interpolation for delivering a radiation beam using jaws and a multi-leaf collimator, including dose-volume histogram evaluation and navigation across clinical trade-offs in a clinical example.
Near real-time dose recalculation after interpolating radiotherapy treatment plans for display.
Use of a computer system and stored computer program product to perform dose calculations in radiotherapy including image registration.
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