Remote Control System for Radiotherapy Neutron Radiation Mitigation
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Solution Overview
Problem
Radiotherapy systems face challenges with high-energy radiation, which generates neutrons that interact with electronic components, causing bit flips and internal transients, particularly due to their proximity to normal neutron flux areas, where existing systems are inadequate.
Innovation Solution
A remote control system with a first computing device in a high-neutron environment controlling a treatment system and a second computing device in a lower-neutron environment, communicating via high-speed serial bus and Ethernet links, using FPGAs with triple modular redundancy and watchdog mechanisms to manage data transfer and ensure fault tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electronic components are located adjacent to the elements they control to minimize cable routing and noise, then cable length and noise pickup are reduced, but neutron-induced bit flips and internal transients increase due to proximity to high neutron flux areas
Solution Approach 1:
The system is divided into two separate computing devices: a first computing device located in the high neutron flux area adjacent to the treatment elements, and a second computing device located in a low neutron flux console area. This segmentation allows each device to operate in its appropriate neutron environment, with the first device handling local sensing and control and the second device handling user interaction and system management.
Solution Approach 2:
A communication interface with serial communication capability serves as an intermediary between the two computing devices. This intermediary transmits commands and data between the console area and the treatment area, enabling the second computing device to control the treatment system without being physically present in the high neutron flux environment.
2Reliability
If a remote control system is implemented to separate the console area from the treatment area, then neutron-induced errors are reduced, but system complexity and communication requirements increase
Solution Approach 1:
The communication interface implements bidirectional feedback communication between the two computing devices. The first computing device sends status information, sensor data, and error signals back to the second computing device, while the second computing device sends control commands and parameter adjustments to the first device. This feedback mechanism ensures reliable operation despite the physical separation.
Solution Approach 2:
The system replaces direct physical connection and control mechanisms with electronic communication through a serial interface. Instead of having the console directly mechanically or electrically connected to treatment components through long cables, the system uses digital communication protocols to transmit control signals and data, reducing the complexity of physical connections while maintaining control functionality.
3Speed
If high-speed serial bus and Ethernet links are used for communication between computing devices, then data transfer speed and real-time control capability are improved, but susceptibility to radiation-induced errors in communication channels increases
Solution Approach 1:
The serial communication interface acts as a radiation-hardened intermediary that protects the high-speed communication channels. By placing the serial interface in the first computing device within the treatment area and using it to encapsulate and transmit data, the system shields the main processing and communication infrastructure from direct radiation exposure while maintaining high-speed data transfer capabilities.
Solution Approach 2:
The system implements redundant data transmission and error checking mechanisms where critical control commands and status information are verified through multiple communication passes. This copying and verification approach ensures data integrity even when radiation-induced errors occur in the communication channels.
Data Source
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AI summary
A remote control system is configured to support communication between a first environment having a first neutron radiation level and a second environment having a second neutron radiation level includes a first computing device and a second computing device. The first computing device is configured to control a treatment system in the first environment. The second computing device is configured to issue commands in the second environment for the treatment system. The first computing device is further configured to determine whether to enable or disable a function supported by the treatment system, determine whether there is pending time-sensitive data to transmit, and periodically transmit a first radiation therapy data collected in the first environment and a first interrupt to the second computing device in a servo loop.