FLASH Radiotherapy Accelerator With Photoconductive Pulse Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radiotherapy systems struggle to deliver intense pulsed radiation at high dose rates required for FLASH therapy while minimizing damage to healthy tissue, as they face limitations in beam current, power requirements, and stability issues, failing to meet the demanding requirements of dose rate control and compactness.
Innovation Solution
A FLASH radiotherapy system using a linear induction accelerator with a photoconductive switch, such as an optical transconductance varistor (OTV), to actively control voltage pulses and beam current, enabling precise dose rate management and stability, allowing multiple beamlets through a single accelerator cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional radiotherapy systems are used to deliver radiation, then treatment can be administered over extended periods, but the dose rate is too low and healthy tissue damage increases
Solution Approach 1:
The patent employs periodic pulsed operation of the linear induction accelerator to deliver radiation in intense bursts rather than continuous low-dose delivery. The photoconductive switch generates periodic voltage pulses that accelerate electron beams in discrete high-dose-rate events, achieving instantaneous dose rates exceeding 1.8×10^5 Gy/s while maintaining average dose rates above 100 Gy/s, which produces FLASH effects that spare healthy tissue
Solution Approach 2:
The patent changes the temporal parameters of radiation delivery by controlling pulse width, repetition frequency, and voltage amplitude through the photoconductive switch. By adjusting these parameters, the system achieves ultra-high instantaneous dose rates while controlling the average dose rate and total treatment time to less than 200 ms, transforming the dose delivery profile from conventional low-dose-rate continuous treatment to high-dose-rate pulsed treatment
2Power
If beam current is increased to achieve higher dose rates, then FLASH therapy requirements are met, but power requirements and system complexity increase
Solution Approach 1:
The system uses periodic pulsed acceleration instead of continuous high-current operation. The photoconductive switch delivers high-voltage pulses that accelerate electrons in brief intervals, achieving ultra-high instantaneous power and dose rate during pulses while allowing the system to reset between pulses. This periodic operation enables FLASH dose rates without requiring sustained high power consumption
Solution Approach 2:
The photoconductive switch is pre-charged with electrical energy before each acceleration pulse. This preliminary energy storage in the switch's capacitive structure allows rapid discharge into the accelerator cavity, generating the high-voltage pulses needed for FLASH dose rates without requiring continuous high-power input during the acceleration event itself
3Productivity
If multiple beamlets are delivered through a single accelerator cavity, then treatment efficiency improves, but control and stability become more difficult
Solution Approach 1:
The patent delivers multiple segmented electron beamlets through the single accelerator cavity by utilizing the periodic pulsed structure. Each voltage pulse from the photoconductive switch can generate a separate beamlet, and these beamlets are delivered in sequence or parallel through the same cavity. This segmentation allows efficient multi-beam treatment while maintaining individual beam control through the timing and shaping of each pulse
Solution Approach 2:
The single accelerator cavity performs multiple functions by accelerating multiple beamlets through the same structure using the same photoconductive switch. The cavity serves as a universal acceleration chamber that can handle different beam configurations, energies, and timing patterns, achieving multi-beam treatment efficiency without requiring separate accelerator systems for each beam
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 achieves instantaneous dose rates exceeding 1.8×105 Gy/s, administers the required dose in less than 200 ms with average dose rates above 100 Gy/s, and maintains a compact form, meeting all therapeutic requirements while ensuring minimal healthy tissue damage.
Implementation Method 1
a photoconductive switch coupled to the particle accelerator and configured to supply the particle accelerator with a plurality of voltage pulses
Implementation Method 2
a magnetic core positioned proximate to the pipe and coupled to the pulsed source
Data Source
AI summary
Methods, devices and systems for ultra-high dose radiotherapy are disclosed. The described techniques rely in-part on active switching control of a photoconductive switch during the time the accelerator is accelerating charged particles to produce the output radiation at the desired dose rates. One radiotherapy system includes a particle accelerator configured to receive charged particles from a pulsed source. The particle accelerator includes a pipe configured to allow the charged particles to pass through as a beam, a magnetic core positioned proximate to the pipe and coupled to the pulsed source, and at least one multilayer insulator positioned adjacent to the pipe and the magnetic core. The system also includes a photoconductive switch coupled to the particle accelerator and configured to supply the particle accelerator with a plurality of voltage pulses.