Radiotherapy Dose Assurance Using Time-Resolved Surface Mapping
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Solution Overview
Problem
Current radiotherapy techniques struggle to accurately account for patient motion and anatomical changes during a treatment fraction, leading to difficulties in quantifying the impact on dose delivery to target tissues and surrounding organs, which can result in out-of-spec dosing and potential harm to healthy tissues.
Innovation Solution
A novel dose calculation method that tracks actual dose delivery by a radiotherapy system based on a time-resolved machine state and patient surface, allowing for real-time adjustment of treatment fractions to compensate for motion and anatomical changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radiotherapy dosing methods are used, then treatment delivery is simplified, but accuracy of dose delivery is compromised due to unaccounted patient motion and anatomical changes
Solution Approach 1:
The treatment fraction is divided into multiple time segments, with dose calculation performed separately for each segment based on machine state and patient surface measurements at that specific time. This segmentation allows accurate tracking of dose delivery despite patient motion, as each segment's dose is calculated independently using the anatomical and machine parameters valid at that moment.
Solution Approach 2:
The system transitions from static dose calculation (based on initial treatment plan) to dynamic dose calculation that continuously updates based on real-time machine state and patient surface measurements. The time-resolved approach captures the dynamic nature of patient anatomy during treatment, allowing the dose calculation to adapt as the patient moves or changes position.
2Measurement precision
If time-resolved dose calculation is implemented, then dosing accuracy is improved, but computational requirements and processing time increase
Solution Approach 1:
The system calculates dose for a plurality of time segments that collectively cover the entire treatment fraction, using enough segments to achieve the desired accuracy threshold. The number of segments is optimized to provide sufficient measurement precision without unnecessarily increasing computational burden - using more segments than the minimum required for acceptable accuracy.
3Reliability
If real-time surface measurements are captured, then patient motion is accounted for, but measurement complexity and data processing requirements increase
Solution Approach 1:
The radiotherapy system is configured to perform multiple functions: delivering radiation therapy, capturing surface measurements, tracking machine state, and calculating dose - all within a single integrated system. The imaging system and control system serve universal purposes, handling both treatment delivery and quality assurance measurements without requiring entirely separate dedicated devices.
Data Source
AI summary
A computer-implemented method of determining dose delivered by a radiotherapy system to a plurality of locations within a region of patient anatomy includes: during a first time segment of a treatment fraction, causing the radiotherapy system to be in a first machine state; during the first time segment, delivering radiation to the region of patient anatomy; generating a first surface map for the region of patient anatomy based on surface measurements acquired during the first time segment; generating a first modified digital volume of the region based on the first surface map; and for each of the plurality of locations within the region of patient anatomy, determining a first radiation dose that is delivered to the location during the first time segment, wherein the first radiation dose is based on the first machine state of the radiotherapy system and the first modified digital volume.