RF Linear Accelerator for Fast Cyclotron Beam Energy Modulation
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Solution Overview
Problem
Cyclotrons used in particle therapy face limitations due to slow energy modulation and high beam losses, leading to costly radiation shielding and inefficiencies in energy management.
Innovation Solution
Combining a cyclotron with a linear accelerator/decelerator, utilizing a high gradient radio frequency structure for fast energy modulation with low beam loss, enabling rapid energy switching and high beam intensity for advanced therapy applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cyclotron with beam degrader is used for energy modulation, then the system can provide energy variation for particle therapy, but the energy modulation is slow (several 100 ms) and beam losses are high
Solution Approach 1:
The system is divided into two functional parts: a cyclotron for generating the charged particle beam at fixed energy, and a separate linear accelerator section for energy modulation. This segmentation allows each component to be optimized independently, with the linear accelerator providing fast energy modulation without compromising the cyclotron's beam generation capability.
Solution Approach 2:
A linear accelerator section is introduced as an intermediary component between the cyclotron and the treatment target. This intermediary device receives the fixed-energy beam from the cyclotron and provides rapid energy modulation through RF fields, thereby solving the contradiction between maintaining beam generation and achieving fast energy variation.
2Adaptability or versatility
If a beam degrader is used for energy modulation, then energy variation is achieved, but beam losses are high leading to large neutron generation requiring costly radiation shielding
Solution Approach 1:
The mechanical beam degrader system is replaced with an electromagnetic field-based linear accelerator section. Instead of using physical materials to slow and scatter the beam (which causes energy loss and neutron generation), the system uses RF electromagnetic fields to precisely control and modulate beam energy, thereby eliminating the harmful effects of beam degradation while maintaining energy modulation capability.
3Ease of operation
If conventional cyclotron with degrader is used, then particle therapy can be delivered, but radiation shielding requirements are high due to neutron generation
Solution Approach 1:
The system converts the potential harm of beam degradation (which causes neutron generation and requires shielding) into a beneficial process. By using a linear accelerator with RF fields to achieve energy modulation without physical degradation, the system eliminates neutron generation while maintaining the ability to deliver particle therapy, thereby removing the need for extensive radiation shielding.
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 combination allows for very fast energy modulation with low beam loss, enabling advanced therapy techniques like 3D repainting and ultra-short dose delivery times, while reducing the need for extensive radiation shielding.
Implementation Method 1
An RF cavity generates an electromagnetic RF field that interacts with the particles guided in the beam transport section is disposed along the beam transport section. A phase and a frequency of the RF field are set such that a variation in the energy of the particles interacting with the RF field is generated.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In various embodiments, a radiation therapy system can include a cyclotron that outputs a charged particle beam. In addition, the radiation therapy system can include an apparatus to receive the charged particle beam from the cyclotron. The apparatus decelerates or further accelerates the charged particle beam to produce a reduced or increased energy charged particle beam. The apparatus can include a radio frequency structure.