Dose-Based MLC Tracking Optimization for Radiation Therapy
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Solution Overview
Problem
Current cancer radiation therapy systems face challenges in accurately delivering radiation to moving tumors due to limitations in multi-leaf collimator (MLC) tracking, leading to inefficiencies and increased radiation exposure to healthy tissues.
Innovation Solution
A dose-based optimization method for MLC tracking that accounts for the radiation dose delivered to a tumor throughout treatment, adapting the MLC to minimize errors caused by patient anatomy motion, and optimizing MLC apertures in real-time to ensure accurate dose delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gating is used for MLC tracking, then the radiation beam can be turned on and off when the tumor comes within the beam, but the treatment becomes time inefficient and requires entire patient movement for drift realignment
Solution Approach 1:
The system dynamically adjusts MLC leaf positions in real-time based on continuous tumor position feedback, replacing static gating methods. The MLC tracking adapts to tumor motion during treatment without requiring patient repositioning, maintaining precision while improving efficiency
Solution Approach 2:
The system implements continuous feedback loops that monitor tumor position and automatically adjust MLC leaf positions accordingly. This real-time feedback mechanism eliminates the need for interruptive gating and patient repositioning, resolving the contradiction between precision and efficiency
2Reliability
If standard MLC tracking is used without dose optimization, then the system can track tumor motion, but it cannot account for accumulated dose or minimize radiation damage to healthy tissue
Solution Approach 1:
The system incorporates dose accumulation feedback that continuously monitors delivered dose and adjusts MLC leaf positions to ensure accurate dose delivery to the moving tumor while preventing overdose to healthy tissues. This feedback mechanism simultaneously improves reliability and reduces harmful radiation exposure
Solution Approach 2:
The system dynamically changes MLC aperture parameters based on real-time tumor position and accumulated dose calculations. By adjusting leaf positions and aperture sizes adaptively, the system maintains precise dose delivery to the target while minimizing exposure to surrounding healthy tissues
3Measurement precision
If real-time MLC adaptation is implemented to account for patient motion, then dose accuracy improves, but the computational complexity and processing requirements increase
Solution Approach 1:
The system segments the complex dose calculation and optimization problem into smaller, manageable components that can be processed in real-time. By dividing the computational task into discrete steps (dose accumulation, error calculation, leaf position optimization), the system achieves high precision while managing computational complexity
Solution Approach 2:
The system performs preliminary calculations and preparations before treatment begins, including initial dose matrix setup and treatment plan optimization. This pre-computation reduces the computational burden during real-time treatment, allowing high-precision dose delivery without excessive processing complexity
Data Source
AI summary
Methods, apparatuses and systems are disclosed for dose-based optimization related to multi-leaf collimator (“MLC”) tracking during radiation therapy. In an example, a method includes calculating a planned radiation dose using an MLC plan in an un-shifted dose volume, acquiring, using a radiation machine, a target position through motion tracking, and shifting the dose volume by the target position. The method also includes integrating a three-dimensional dose into a two-dimensional beam's eye view grid and fitting, using the radiation machine for each leaf track, an MLC aperture by minimizing a cost function. The method further includes calculating and accumulating a delivered dose based on the fitted leaf positions of the MLC and updating a gantry position and MLC leaves to update a next planned dose.