SPORT Radiation Therapy Non-Uniform Angular Sampling
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Solution Overview
Problem
Conventional radiation therapy techniques, such as IMRT and VMAT, face challenges in achieving optimal dose distribution due to insufficient angular sampling and oversampling, leading to inefficient treatment planning and delivery, particularly in rotational arc therapy where multiple arcs are often required.
Innovation Solution
The introduction of a station parameter optimized radiation therapy (SPORT) method that differentially distributes control points in angular space based on demand metrics, allowing for non-uniform angular beam sampling and sparse intensity modulation, enabling improved dose distribution and delivery efficiency using a volumetric modulated arc therapy system with additional segments to boost desired regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional VMAT discretizes angular space into equally spaced control points, then the treatment planning is simplified, but the angular sampling is insufficient in some regions and excessive in others, leading to poor dose distribution
Solution Approach 1:
The patent applies local quality by transitioning from uniform angular sampling to non-uniform angular sampling, where the density of control points is locally adapted to the specific anatomical and dosimetric requirements of different angular regions. This allows higher sampling density in regions requiring precise dose modulation and lower density in regions where uniform sampling suffices, thereby resolving the contradiction between planning simplicity and dose distribution quality.
Solution Approach 2:
The patent implements dynamics by making the angular sampling distribution adaptive rather than static. The control point spacing is dynamically adjusted based on a demand metric that evaluates the local need for intensity modulation at each angular position, allowing the system to optimize sampling density according to the specific treatment case requirements rather than applying a fixed uniform pattern.
2Manufacturing precision
If multiple arcs are used in VMAT to achieve sufficient angular sampling, then the dose distribution improves, but the treatment delivery time increases
Solution Approach 1:
The patent applies parameter changes by modifying the angular sampling parameter from a fixed uniform distribution to a variable non-uniform distribution optimized for each treatment case. This allows achieving the necessary angular sampling density for high-quality dose distribution within a single arc, eliminating the need for multiple arcs and thereby reducing treatment delivery time while maintaining dose distribution quality.
3Manufacturing precision
If conventional IMRT uses 5-10 beams to provide intensity modulation, then the angular sampling is sufficient, but the treatment complexity and delivery time increase
Solution Approach 1:
The patent applies dimensionality change by transitioning from discrete beam directions (0D/1D approach) to continuous arc rotation with non-uniform angular sampling (adding temporal and angular continuity dimensions). This allows achieving sufficient angular sampling coverage equivalent to multiple discrete beams but delivered through a more efficient arc-based approach with optimized control point distribution, reducing overall treatment complexity.
Data Source
AI summary
A method of radiation therapy planning and delivery is provided that includes introducing a demand metric, using a volumetric modulation arc therapy system, to select a spatially optimized and non-uniform set of station or control points to be used for intensity modulation, where the set of station or control points are uniform or non-uniform, and selecting a set of control points at different gantry angles, using the volumetric modulated arc therapy system, and using the demand metric to prioritize which station or control point receives intensity modulation, where the volumetric modulated arc therapy system is differentially boosted at selected angles by inserting additional segments to the station, where the inserted additional apertures dosimetrically boost desired regions in a planning target volume to improve planning target volume coverage in a single arc rotation while sparing sensitive structures.