Sparse Passive Proton Filter for FLASH Dose and Energy Modulation
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Solution Overview
Problem
Current proton therapy systems face challenges in achieving simultaneous intensity and energy modulation for ultra-high dose rate (UHDR) proton therapy, leading to increased spillover to serial organs at risk (OARs) and suboptimal linear energy transfer (LET) optimization, which compromises clinical outcomes and the interpretation of preclinical studies.
Innovation Solution
The development of patient-specific sparse passive filters that modulate proton beams based on a simultaneous optimization of dose, dose-averaged dose rate (DADR), and dose-averaged linear energy transfer (LETd) to target a specific area while sparing OARs, using an inverse optimization approach called Simultaneous Intensity and Energy Modulation and Compensation (SIEMAC).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If passive energy modulation is used to achieve conformal delivery of FLASH fields, then energy modulation is achieved, but filter design becomes difficult
Solution Approach 1:
The filter is divided into multiple discrete elements (ridges or pins) that can be independently optimized. Each element corresponds to a specific energy modulation requirement, allowing the complex filter design problem to be broken down into manageable segments that can be designed and manufactured separately
Solution Approach 2:
The filter design is performed in advance using computational optimization algorithms that calculate the optimal geometry of each filter element before manufacturing. This preliminary computational design phase resolves the complexity of filter design by automating the optimization process and providing clear manufacturing specifications
2Object-affected harmful factors
If ultra-high dose rate (UHDR) proton beams are used for FLASH therapy, then OAR sparing is improved, but simultaneous intensity and energy modulation becomes impractical
Solution Approach 1:
A passive energy modulating filter is introduced as an intermediary component between the proton beam source and the patient. This filter performs both energy modulation and intensity modulation functions, enabling conformal FLASH delivery without requiring complex active modulation systems that would be impractical at UHDR
Solution Approach 2:
The filter design optimizes multiple parameters simultaneously including element geometry, material composition, and spatial arrangement to achieve the desired dose, dose rate, and LET distributions. This multi-parameter optimization enables simultaneous intensity and energy modulation through a single passive component
3Loss of time
If transmission beam is used for FLASH delivery, then delivery time is reduced, but spillover to serial OARs increases
Solution Approach 1:
The filter is designed with segmented ridges or pins that create multiple localized Bragg peaks, allowing the beam to be effectively segmented in terms of energy deposition patterns. This segmentation enables precise targeting while minimizing spillover to surrounding OARs during rapid FLASH delivery
Solution Approach 2:
The filter provides locally optimized energy modulation for different regions of the beam path. Each filter element is designed to create the appropriate dose distribution for its specific anatomical region, ensuring that high dose is delivered only to the target while serial OARs receive minimal exposure during the rapid FLASH delivery
4Reliability
If treatment margin is added to account for uncertainties, then target coverage is improved, but dose to OARs increases
Solution Approach 1:
The filter design provides locally optimized dose distributions that maintain appropriate margins for target coverage uncertainty while creating sharp dose fall-off at the distal edge of the treatment field. This local optimization ensures that OARs beyond the target margin receive minimal dose even when margins are necessary for robust target coverage
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
This approach reduces the spread of dose, DADR, and LETd in OARs, enhancing the sparing of organs at risk and improving the precision of proton therapy plans.
Implementation Method 1
directing the beam of particles to a patient specific sparse passive filter to form an adjusted beam of particles, wherein the patient specific sparse passive filter is configured to modulate the beam of particles
Data Source
AI summary
The present disclosure provides for systems and methods for designing patient-specific sparse passive filters, for example compensation and modulation components, for simultaneous intensity and energy modulation in energetic entity or particle (e.g., proton) therapy, radiation therapy methods and systems, method for treating cancer in a patient or animal subject, method of optimizing an administration plan in particle FLASH radiotherapy or non-FLASH radiotherapy, configuration of the device or system to effectively place the patient-specific sparse passive filter, and the like.