A Preliminary Study on a Real-time Dose Monitoring System Based on Scintillating Fibers for Brachytherapy

Abstract

Purpose: We developed and evaluated a preliminary scintillating fiber-based real-time dose monitoring system (SRDMS) for brachytherapy.

Materials and methods: The SRDMS consisted of a detector section with 10 scintillating fibers (BCF-12, Saint Gobain Inc., S.A. France) inserted into a long barrel cylinder and a readout system comprising a photo-multiplier tube (PMT H12428-203 MOD, Hamamatsu Photonics, Shizuoka, Japan) and National Instrument Measurement & Automation Explorer (NI MAX, National Instruments, TX, USA). Basic system performance was estimated by measuring the dwell position and time for various patterns of source motion. Signal output response with data sampling, linearity, and reproducibility was also evaluated. In addition, dwell position and time measurement via the SRDMS were compared across three treatment plans, which were applied to a silicone-based human phantom to evaluate the system’s response to more complex and realistic situations.

Results: The difference between the measured source dwell position and plan was -0.52 ± 0.53 mm. The difference between the measured dwell time and plan was 7 ± 5 ms. For signal output verification, the signal-to-SD ratio was less than 1.5%. The signal output linearity was maintained at -0.43 ± 0.50%, and reproducibility was 1.35 ± 1.44%.

Conclusions: In this study, we demonstrated that the SRDMS can accurately detect relative dwell positions and dwell times. In further studies, we plan to verify the accuracy of relative source strength, and update the SRDMS with real-time monitoring. The SRDMS could be used for real-time dose monitoring during brachytherapy.