Patient-Specific Locally Varying Margin for Radiotherapy Motion Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radiation therapy planning faces challenges in accurately distributing high doses to cancer cells while minimizing exposure to healthy cells, particularly sensitive organs at risk, due to uncertainties in tumor spread, patient motion, and positioning inaccuracy, often relying on generic margins that do not account for individual and location-specific variations in patient motion.
Innovation Solution
A method using patient-specific, locally varying margins determined from multiple medical images acquired over a time interval similar to the radiotherapy fraction, allowing for precise compensation of intrafraction and interfraction motion, which can be adapted continuously during treatment to ensure optimal dose distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If generic margins are used to compensate for patient motion, then the treatment target is adequately covered, but the organs at risk receive excessive radiation dose
Solution Approach 1:
The patent applies local quality by transitioning from uniform generic margins to locally varying patient-specific margins. The margin is calculated differently for different locations based on actual motion measurements at each specific location, allowing optimal protection of organs at risk while maintaining target coverage where motion occurs
Solution Approach 2:
The patent changes the margin parameter from a fixed generic value to a dynamic patient-specific value that varies by location. The margin is recalculated based on measured motion parameters for each patient and location, transforming it from a static safety buffer to an adaptive parameter that reflects actual clinical conditions
2Reliability
If larger margins are applied to account for motion uncertainty, then the treatment target is adequately covered, but the precision of dose distribution to cancer cells decreases
Solution Approach 1:
The patent applies local quality by making the margin location-dependent rather than uniform. Areas with measured high motion receive larger margins, while areas with minimal motion receive smaller margins, preserving dose precision in stable regions while ensuring coverage in mobile regions
Solution Approach 2:
The patent applies partial action by using only the necessary margin size for each location based on actual motion measurements. Instead of applying excessive uniform margins everywhere, the margin is precisely calibrated to the measured motion at each location, avoiding unnecessary dose spread
3Measurement precision
If patient-specific motion quantification is implemented, then the margin accuracy is improved, but the complexity of the treatment planning process increases
Solution Approach 1:
The patent applies self-service by having the system automatically perform motion quantification and margin calculation based on acquired images. The computer program autonomously processes the imaging data, identifies motion patterns, and generates patient-specific margins without requiring complex manual intervention or expertise
4Reliability
If multiple medical images are acquired over time to determine patient-specific margins, then the representativeness of the margin for individual patient motion is improved, but the acquisition time and treatment delay increase
Solution Approach 1:
The patent applies preliminary action by acquiring multiple images over time before treatment to establish the patient-specific motion pattern. This pre-acquisition data collection allows the system to characterize individual motion behavior in advance, creating a reliable basis for margin calculation that represents the patient's typical motion during treatment
Data Source
AI summary
It is an object of the invention to provide for an improved radiation treatment. According to a first aspect of the invention, this object is achieved by a method for determining a patient specific locally varying margin on a treatment target and/or an organ at risk in order to compensate for local intrafraction motion expected during a radiotherapy fraction to be delivered over a radiotherapy fraction time interval. The patient specific locally varying margin is determined based on a displacement and/or an estimate of the displacement of at least a first location and a second location on the treatment target and/or organ at risk. The method comprises steps of: acquiring a first medical image of the treatment target and/or the organ at risk and acquiring a second medical image of the treatment target and/or the organ at risk, wherein the time between the acquisition of the first medical image and the second medical image is similar to the radiotherapy fraction time interval and determining of positions of the first location and the second location in the first medical image and in the second medical image and using the determined positions for determining the patient specific locally varying margin around the treatment target and/or organ at risk.