Oblique Dual X-Ray Tube Layout for Uniform FLASH Dose at Depth
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Solution Overview
Problem
Current systems for ultra-high dose rate x-ray irradiation, such as those used in FLASH radiotherapy, face challenges in achieving uniform dose rates and depth-dose uniformity, particularly with kV x-rays, which are essential for preclinical research on small animals, due to the limitations of stationary anode technology and the need for more advanced radiation sources.
Innovation Solution
A self-shielded x-ray irradiation system utilizing a pair of rotating anode x-ray tubes arranged at oblique angles to intersect within a target volume, allowing for simultaneous emission of x-ray beams that achieve uniform dose rates of 40-200 Gy/s with depth-dose uniformity, suitable for murine models, and capable of conventional dose rates as well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single x-ray tube is used to irradiate the target, then the device complexity is low, but the dose rate uniformity at depth is insufficient
Solution Approach 1:
The irradiation system is segmented into multiple x-ray tubes (at least two) that independently irradiate the target from different directions. This segmentation allows the dose distribution to be divided and combined, achieving uniform dose rate at depth while maintaining manageable complexity in each individual tube component.
Solution Approach 2:
The solution transitions from a single-direction (one-dimensional) irradiation approach to multi-directional (three-dimensional) irradiation by arranging x-ray tubes at different spatial positions and angles. This dimensional change enables the beams to converge at the target, achieving depth-dose uniformity that cannot be obtained with a single tube.
2Productivity
If high energy particles (electrons, protons) are used to achieve ultra-high dose rates, then the dose rate requirement is met, but the accessibility and logistical availability are limited
Solution Approach 1:
The system uses standard, commercially available x-ray tubes that can be obtained from regular suppliers, making the system self-sufficient and accessible without requiring specialized facilities. The x-ray tubes generate the necessary radiation locally, eliminating dependence on external particle accelerators or specialized centers.
Solution Approach 2:
The invention replaces expensive, complex particle accelerators with relatively inexpensive, commercially available x-ray tubes. While x-ray tubes have limited lifespan compared to accelerators, their lower cost and availability make them a practical substitute for achieving ultra-high dose rates in accessible settings.
3Productivity
If electron beams are used for FLASH irradiation, then ultra-high dose rates are achieved, but lateral scattering and spreading occur reducing localization precision
Solution Approach 1:
The invention uses x-ray photons as an intermediary medium to deliver ultra-high dose rates without the lateral scattering problems of electron beams. X-rays penetrate the target with minimal scattering, and the dose is deposited through photoelectric and Compton interactions, providing better spatial localization while maintaining FLASH dose rates.
Solution Approach 2:
The solution changes the radiation type parameter from electrons to x-rays. This parameter change fundamentally alters the interaction physics: x-rays exhibit minimal lateral scattering compared to electrons, enabling precise localization of the irradiation field while still achieving the required ultra-high dose rates through multiple tube convergence.
4Manufacturing precision
If kV x-ray beams are used, then lateral spread is minimal providing good localization, but the dose rate at depth is insufficient for FLASH effects
Solution Approach 1:
Multiple kV x-ray beams from different tubes are merged and converged at the target location. Individually, each kV beam provides good localization with minimal lateral spread. By combining multiple such beams that all converge on the same target volume, the localized dose rates add up to achieve the ultra-high FLASH dose rates while preserving the localization advantage of kV x-rays.
Solution Approach 2:
The solution addresses the depth dose rate limitation by adding spatial dimensions to the irradiation geometry. Instead of relying on a single kV beam's depth penetration, multiple kV beams from different angular directions are converged at the target, delivering dose from multiple dimensions simultaneously. This achieves both the localization of kV x-rays and the high dose rate needed for FLASH effects.
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
The system provides flexible dose rate adjustment between 0.02 Gy/sec to 200 Gy/sec, achieving uniform dose distribution and enabling broader research into FLASH effects, particularly with kV x-rays, thereby advancing the understanding and application of FLASH radiotherapy.
Implementation Method 1
a first x-ray tube constructed and arranged to be able to irradiate an object with at least a portion of a first x-ray beam emitted from the first x-ray tube
Data Source
AI summary
An x-ray irradiation system includes a first x-ray tube constructed and arranged to be able to irradiate an object with at least a portion of a first x-ray beam emitted from the first x-ray tube, and a second x-ray tube constructed and arranged to be able to irradiate the object with at least a portion of a second x-ray beam emitted from said second x-ray tube simultaneously with said first x-ray beam. The first and second x-ray tubes are arranged such that the first and second x-ray beams are incident on, and intersect within, the object at respective first and second oblique angles to define a target volume such that a dose rate is substantially uniform as prescribed within said target volume.