evelopment of an Innovative Real-Time Dosimetry Monitoring System for Heavy Ion Radiotherapy

ancer is the second leading cause of mortality globally. As a critical technological approach in oncology treatment, radiation therapy is evolving from conventional radiotherapy to ultra-high dose rate radiotherapy (FLASH-RT). With the significant escalation in radiotherapy dose rates, real-time dosimetry monitoring faces the dual challenges of enhancing both response time and measurement precision. This work successfully developed a real-time dosimetry monitoring system for radiotherapy, designed to accommodate a broad range of dose rates. The system consists of a dual-gated integrator architecture front-end circuit and a high-speed data acquisition circuit, providing accurate detection of bipolar current pulse signals spanning from -190 A to +200 A, the minimum current measurement range is from -1 pA to 1 pA. Two significant technological advancements were accomplished: (1) The elimination of signal processing dead time resulted in a reduction of the single-event readout time to 5 s; (2)The nonlinear error from -190 A up to the maximum current is within 0.67%, with a linear correlation coefficient (R2)of 0.99992. The experiments were conducted using an ionization chamber detector at the Heavy Ion Research Facility in Lanzhou (HIRFL-TR4), this system, combined with a dose detector, achieves real-time dose measurement within the dose rate range of 65 Gy/min to 120 Gy/min. It demonstrates excellent real-time monitoring performance in the high-dose rate range of radiation therapy and shows potential for further application in dose monitoring for electron and proton beam radiotherapy.