Aperture Leaf Sequencing for Radiation Dose Control
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Solution Overview
Problem
Current radiation therapy systems face challenges in achieving precise control over three-dimensional dose distribution within a treatment volume, particularly due to limitations in rotating apertures and leaf positions, which result in lengthy computation times and inefficient delivery of radiation fluence levels.
Innovation Solution
The system employs a computing device with a fluence determination engine and leaf position calculator to calculate optimal leaf positions for multiple discrete fluence levels during a single rotation of the aperture, allowing for customized radiation delivery to different parts of the treatment volume by dividing leaves into groups and assigning specific configurations at opposing positions around the arc of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the aperture is rotated more than once around the treatment volume to achieve multiple fluence levels, then control over three-dimensional dose distribution is improved, but treatment time increases
Solution Approach 1:
The aperture leaves are divided into multiple groups (e.g., first group, second group, third group) that can be independently positioned. Each group can be configured to different positions simultaneously, enabling multiple fluence levels to be achieved in a single rotation without requiring multiple rotations around the treatment volume.
Solution Approach 2:
The system dynamically adjusts leaf positions at different angular positions during a single rotation. By calculating and implementing different leaf configurations at specific angles (e.g., 0-180 degrees for first fluence level, 180-360 degrees for second fluence level), the system achieves multiple fluence levels without additional rotation cycles.
2Manufacturing precision
If iterative algorithms are used to determine optimal leaf positions, then dose distribution control is improved, but computation time increases
Solution Approach 1:
Leaf positions for multiple fluence levels are calculated in advance using closed-form mathematical formulas rather than iterative algorithms. The system pre-determines the optimal positions of leaves in different groups based on the desired fluence levels and treatment geometry, eliminating the need for time-consuming iterative optimization during treatment planning.
Solution Approach 2:
The patent replaces iterative computational algorithms with direct mathematical calculations. By using analytical solutions based on geometric relationships and fluence requirements, the system achieves rapid computation of leaf positions without relying on repeated trial-and-error optimization cycles.
3Productivity
If multiple discrete fluence levels are provided in a single rotation, then treatment efficiency is improved, but leaf position control complexity increases
Solution Approach 1:
The leaf aperture is segmented into multiple independently controllable groups. Each group can be positioned differently at different angular positions during rotation, enabling the system to deliver multiple discrete fluence levels (e.g., first fluence level, second fluence level at half the first amount) simultaneously without requiring complex coordinated movement of all leaves.
Data Source
AI summary
Systems and methods of controlling the leaves of an aperture in radiation treatment are disclosed. In some embodiments, these systems and methods allow the delivery of different radiation fluences to different parts of a treatment volume in a single rotation of the aperture around the treatment volume. In some embodiments, different radiation fluences are achieved by radiating different parts of the treatment volume from opposing positions of the aperture around the treatment volume. In some embodiments, different radiation fluences are achieved by assigning different leaf pairs to radiate different parts of the treatment volume.