Pencil Beam Scanning Dose Rate Calculation Using Spot Timing
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Solution Overview
Problem
Existing pencil beam scanning (PBS) radiation therapy techniques fail to accurately account for the temporal separation between dose deliveries to spots, leading to inconsistent and imprecise characterization of dose rates within the treatment field.
Innovation Solution
A method to calculate and report dose rates at local regions or voxels within a PBS treatment field by considering dose accumulation as a function of time, taking into account the unique spatiotemporal delivery patterns of PBS FLASH radiotherapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the temporal separation between spots delivering dose is not accounted for, then the dose rate estimate remains simple and consistent across different delivery patterns, but the dose rate characterization becomes imprecise and inconsistent for PBS fields
Solution Approach 1:
The patent segments the PBS delivery process into discrete spot deliveries, calculating the dose rate for each spot individually based on its specific delivery time and dose contribution. This segmentation allows precise characterization of temporal separation between spots while maintaining systematic organization through voxel-based dose accumulation tracking.
Solution Approach 2:
The patent introduces a temporal dimension to the dose rate calculation by considering the time at which each spot delivers its dose. Instead of treating dose delivery as a spatial-only problem, the solution incorporates time as an additional dimension, calculating dose rates based on the temporal sequence of spot deliveries and their cumulative effect on each voxel.
2Measurement precision
If scanning time is not considered in PBS, then the dose delivery process is simpler to manage, but the temporal separation between spots is not accounted for leading to inaccurate dose rate estimates
Solution Approach 1:
The patent performs preliminary calculations of spot delivery times and dose contributions before computing the final dose rate. By pre-determining the temporal characteristics of each spot delivery and its impact on affected voxels, the system efficiently incorporates scanning time considerations without excessive computational overhead during the main dose rate calculation phase.
Solution Approach 2:
The patent creates a temporal model that copies and represents the actual sequence of spot deliveries in computational form. This virtual representation of the delivery timeline allows the system to analyze and calculate dose rates based on temporal separation without requiring physical measurement or intervention in the actual scanning process.
Data Source
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AI summary
The dose rate of voxels within a particle beam (e.g., proton beam) treatment field delivered using pencil beam scanning (PBS) is calculated, and a representative dose rate for the PBS treatment field is reported. The calculations account for dose accumulation in a local region or sub-volume (e.g., a voxel) as a function of time.