Leaf Sequencing Algorithm for Moving Target Radiation Therapy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radiation therapy systems fail to account for the periodic movement of tumors and surrounding tissues during treatment, leading to significant variations in radiation delivery, with potential under or over-dosing of the target region and surrounding tissues.
Innovation Solution
The method involves orienting the multi-leaf collimator (MLC) aperture parallel to the target's trajectory, ensuring that the radiation beam moves perpendicularly to the target's motion, allowing for a more consistent and controlled delivery of radiation doses by synchronizing leaf movements with the target's motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional radiation therapy systems are used without accounting for target motion, then the treatment plan can be developed and implemented, but significant variations in radiation delivery occur leading to under or over-dosing of the target region and surrounding tissues
Solution Approach 1:
The patent applies dynamics by making the MLC aperture and radiation beam movable to track and follow the periodic motion of the target. The leaves are positioned and moved in synchronization with the target's trajectory, transforming the static treatment approach into a dynamic one that adapts to target motion, thereby maintaining radiation delivery precision and treatment effectiveness throughout the treatment cycle.
Solution Approach 2:
The patent employs preliminary action by pre-planning the MLC leaf sequences and aperture movements based on the known periodic trajectory of the target. The treatment plan is developed with advance knowledge of the target's motion pattern, allowing the system to pre-position leaves and pre-coordinate beam movements to compensate for upcoming target displacement, ensuring consistent dose delivery.
2Area of stationary object
If the MLC aperture is oriented perpendicular to the target's trajectory, then the radiation beam can cover the target area, but the target motion causes significant variation in the received fluence
Solution Approach 1:
The patent applies dimensionality change by reorienting the MLC aperture from a perpendicular orientation to a parallel orientation relative to the target's trajectory. This dimensional reconfiguration allows the radiation beam to move in a direction that follows the target's motion, transforming the geometric relationship between beam and target to eliminate fluence variation caused by target displacement.
3Adaptability or versatility
If the leaves of the MLC are moved continuously to deliver IMRT, then the intensity distribution can be controlled, but the periodic motion of the target causes interplay effects that degrade dose distribution
Solution Approach 1:
The patent applies feedback by coordinating the MLC leaf movements and radiation beam delivery with the periodic motion of the target. The leaf sequencing is designed with feedback from the known target trajectory, adjusting aperture position and shape in real-time to compensate for target displacement, thereby maintaining accurate dose distribution despite continuous leaf movement and target motion interplay.
Data Source
AI summary
A method of providing intensity modulated radiation therapy to a moving target is disclosed. The target moves periodically along a trajectory that is projected onto a multi-leaf collimator (MLC) plane. The MLC plane is divided into thin slices parallel to the movement of the target. The present invention optimizes the leaf sequence such that, within each slice, if a point receives radiation, all other points in that slice that receive the same amount or more fluence are also receiving radiation at the same time.