Side Effect Reduction Strategy for High-Voltage Power Supplies in Radiotherapy

Radiotherapy kills tumor cells through high-energy rays, but the damage of rays to normal tissues will cause side effects. As the core power source of the ray generating device, the output stability of the high-voltage power supply (HVPS) for radiotherapy directly affects the accuracy of ray dose, which is a key link to reduce side effects. The current HVPS for radiotherapy has problems such as voltage drift and pulse timing deviation, which easily lead to ray dose fluctuation and aggravate the damage of normal tissues.
To solve the problem of voltage stability, a dual closed-loop feedback control strategy is adopted: the outer loop takes the output voltage as the control target, uses the fuzzy PID algorithm to dynamically adjust the duty cycle of the PWM signal, and controls the voltage stability within ±0.01%; the inner loop introduces current feedback to suppress the current impact caused by load mutation in real time, avoiding dose deviation caused by current fluctuation. At the same time, a multi-stage RC filter circuit is designed at the high-voltage output end to reduce the ripple coefficient to less than 0.05%, reducing the fluctuation of ray energy.
In terms of precise pulse timing control, an FPGA chip is used to generate high-frequency pulse signals, and clock synchronization technology is used to realize the timing coordination between HVPS and the dose monitoring system, with the pulse width error controlled within 5ns. Combined with the dynamic tracking technology of tumor position, when the patient's body position shifts slightly during treatment, HVPS can adjust the output pulse frequency within 100μs according to the feedback from the dose monitoring system, ensuring that the rays are accurately focused on the tumor target area and reducing the irradiated dose of normal tissues.
In addition, a temperature compensation module is designed to monitor the internal temperature of HVPS in real time through a platinum resistor. When the temperature change exceeds ±2℃, the reference voltage is automatically adjusted to avoid output deviation caused by temperature drift. In the clinical application of a tumor hospital, the incidence of side effects such as radiation dermatitis and digestive tract reactions in patients is reduced by 28%, and the dose deviation of the tumor target area is controlled within ±2%, which significantly improves the safety and effectiveness of radiotherapy.