Dose Volume Histogram Calculation Using Randomized Voxel Sampling
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Solution Overview
Problem
Existing methods for generating dose-volume histogram (DVH) curves are computationally intensive and inaccurate, particularly for small targets and regions with sharp dose gradients, due to the use of oversampling techniques, which require large super-sampling factors to achieve precision.
Innovation Solution
The use of statistical-based randomized sampling techniques to generate a randomly spaced point cloud of arbitrary size for each voxel within a volume-of-interest (VOI), interpolating dose values, and applying point-in-polygon testing to create a DVH curve, reducing computational intensity while maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oversampling technique with large super-sampling factors is used to improve DVH accuracy for small targets and sharp dose gradients, then measurement precision improves, but computational complexity increases rapidly
Solution Approach 1:
The patent replaces the traditional mechanical grid-subdivision approach with a statistical sampling method. Instead of systematically subdividing the dose grid into sub-voxels, the invention uses randomized sampling of voxel centers to estimate DVH parameters, substituting a computational statistical approach for the deterministic grid-based method.
Solution Approach 2:
The invention changes the fundamental parameter of sampling strategy from systematic oversampling (dividing each voxel into N sub-voxels) to randomized sampling (selecting M voxel centers randomly). This parameter change transforms the computational complexity from O(N^3) for fine grid resolution to a much more efficient randomized selection process that achieves comparable accuracy with fewer samples.
2Measurement precision
If the number of computations is increased to improve DVH precision for small targets, then measurement precision improves, but productivity decreases
Solution Approach 1:
The patent replaces the computationally intensive mechanical process of fine grid resolution with a statistical sampling approach. By randomly selecting voxel centers and using probability-based estimation, the system achieves accurate DVH calculations for small targets without requiring exhaustive computation of all grid points.
Solution Approach 2:
The invention changes the computational parameter from processing all N^3 grid points to processing only M randomly selected voxel centers. This parameter change dramatically reduces computation time while maintaining precision for small targets, as the randomized sampling efficiently captures the dose distribution characteristics without exhaustive enumeration.
3Measurement precision
If dose grid resolution is increased to accurately represent sharp dose gradients, then measurement precision improves, but use of energy increases due to higher computational burden
Solution Approach 1:
The patent replaces the energy-intensive process of computing fine grid resolution with a statistical sampling method. By using randomized selection of voxel centers and probability-based dose estimation, the system accurately represents sharp dose gradients without requiring the computational energy needed for exhaustive grid processing.
Data Source
AI summary
Disclosed herein are statistical methods that use randomized sampling to generate a precise dose volume histogram (DVH) without the computational intensity of subdivision methods that rely on super-sampling of a 3D dose image. One variation of a method rapidly generates a DVH from a dose image by generating a randomly spaced point cloud of arbitrary size for each voxel of a volume of interest (VOI). These methods may be used to help expedite radiotherapy treatment planning and/or facilitate clinician review of whether a radiation dose distribution is acceptable. These methods may also be used to facilitate the calculation of bounded DVH curves. In some variations, adaptive radiotherapy methods may use these rapidly-generated DVHs to update or adjust radiation delivery on the day of treatment.