SFRT Treatment Planning With CRI and SP-CIV Metrics
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Solution Overview
Problem
Conventional radiation therapy planning systems fail to adequately account for the spatial distribution of dose, leading to inadequate sparing of healthy tissue and insufficient consideration of patient motion during treatment, particularly in spatially fractionated radiation therapy (SFRT) and proton-SFRT.
Innovation Solution
Introduce new metrics such as the critical/repair ratio index (CRI) and spatial periodicity of critical isodose value (SP-CIV) to optimize treatment planning, incorporating the spatial distribution of dose and mitigating the effects of patient motion, using techniques like dynamic spot focusing and magnetic beam steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional radiation therapy planning systems are used, then treatment planning can be performed, but the spatial distribution of dose is not adequately accounted for, leading to insufficient sparing of healthy tissue
Solution Approach 1:
The patent introduces new metrics (CRI and SP-CIV) that change the parameters used to evaluate treatment plans. Instead of relying on conventional DVH metrics that only consider volume, the new metrics incorporate spatial distribution characteristics, allowing the planning system to optimize for both healthy tissue sparing and dose homogeneity in the target volume.
Solution Approach 2:
The patent replaces the conventional treatment planning approach with a new metric-based system. The CRI (critical/repair ratio index) and SP-CIV (spatial periodicity of critical isodose value) metrics substitute for traditional volume-based DVH metrics, enabling the system to account for spatial dose distribution and motion effects without requiring complex mechanical motion compensation devices.
2Object-affected harmful factors
If spatially fractionated radiation therapy is used to improve healthy tissue sparing, then peak-to-valley dose distribution is achieved, but patient motion during treatment smooths out the dose distribution, reducing the advantage
Solution Approach 1:
The patent applies motion mitigation strategies during the treatment planning phase rather than during treatment delivery. By incorporating motion models and uncertainty margins into the planning process, the system proactively compensates for expected motion effects, ensuring that the peak-to-valley dose distribution is maintained despite patient motion during treatment.
Solution Approach 2:
The new metrics provide feedback on the robustness of the treatment plan to motion effects. The CRI and SP-CIV metrics allow planners to evaluate how motion will affect the dose distribution and adjust the plan accordingly, creating a feedback loop that improves reliability without sacrificing healthy tissue sparing.
3Ease of operation
If conventional DVH metrics are used to evaluate treatment plans, then planning can be simplified, but the spatial distribution of dose is not accounted for, leading to inadequate healthy tissue sparing
Solution Approach 1:
The patent extends conventional DVH metrics by adding spatial distribution parameters (CRI and SP-CIV) without completely replacing the familiar DVH framework. This allows treatment planners to use the same user interface and workflow while incorporating additional metrics that account for spatial dose distribution, maintaining ease of operation while improving healthy tissue sparing.
4Reliability
If motion mitigation strategies are incorporated into treatment planning, then the impact of patient motion is reduced, but the complexity of the planning process increases
Solution Approach 1:
The patent replaces complex mechanical motion compensation systems with a software-based metric approach. Instead of requiring complex real-time motion tracking and adjustment hardware, the system uses CRI and SP-CIV metrics to evaluate and optimize plans for motion robustness, reducing device complexity while maintaining reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the ability to deliver a homogeneous curative dose across the target volume while minimizing exposure to healthy tissue and reducing the impact of patient motion during treatment, improving the efficacy of SFRT, EDR RT, UHDR RT, and FLASH RT.
Implementation Method 1
A proton beam reaches a depth in tissue that depends on the energy of the beam, and releases most of its energy (delivers most of its dose) at that depth. The region of a depth-dose curve where most of the energy is released is referred to as the Bragg peak of the beam.
Implementation Method 2
In SFRT/IMPT, beams are focused into the target volume with a collimator and/or with scanning magnets in the nozzle of the treatment machine.
Implementation Method 3
In SFRT/IMPT, beams are focused into the target volume with a collimator and/or with scanning magnets in the nozzle of the treatment machine.
Data Source
AI summary
One or more new metrics are introduced into the treatment planning process. More specifically, a correcting factor/metric referred to herein as the critical/repair ratio index is introduced, and/or a correcting factor/metric referred to herein as the spatial periodicity of critical isodose value is introduced. By using these metrics, the expected sparing from the spatial distribution of dose is better accounted for in treatment modalities including spatially fractionated radiation therapy (SFRT) in general and SFRT with ultra-high dose rates in particular. According to a treatment planning strategy, the target can be covered by a Spread-Out Bragg Peak, to optimize and/or homogenize the dose distribution at the target level but still benefit from the sparing effect of SFRT at the healthy tissue level. Delivery techniques include a dynamic focusing technique and a magnetic beam steering technique. Enhancing dose rate enables maximizing the peak-to-valley dose distribution with SFRT despite patient motion.