Room: Davidson Ballroom A
Purpose: In HDR brachytherapy, the lack of clinically available, real-time, in-vivo dosimetry systems, can lead to potential treatment (TX) errors being missed entirely, or only realized post TX. The purpose of this work was to design and test an interface capable of identifying potential HDR delivery errors.
Methods: A LabView platform was designed for real time acquisition and display of voltages from a scintillating nanoparticle-terminated fiber-optic dosimeter (NanoFOD) during HDR delivery. This voltage was overlaid on the expected detector signal calculated using the dose distribution exported from the treatment planning system and a previously obtained distance-based calibration curve for the NanoFOD. To test the interface, a setup was designed consisting of either one or two HDR catheters, with the NanoFOD embedded at a specific location. This set up was imaged to localize the NanoFOD, and plans were generated using one, or two catheters. The expected voltages at the NanoFOD location were calculated and imported to the LabView interface. Both plans were delivered and monitored in real-time, initially as planned, and then introducing known errors: wrong source guide tube length, and switching the two channels when connecting to the afterloader.
Results: The designed interface was successful in displaying in real time the measured voltage, correctly accounting for background noise, and also automatically detecting the location of the first dwell to start the overlay with the expected signal. When the plans were delivered correctly, there was agreement between measured and expected voltages. When errors were introduced, the interface detected large differences, at which point the delivery should be stopped and discrepancies investigated.
Conclusion: A novel platform using NanoFOD detectors was designed to allow for real time tracking of delivered dose during HDR treatments. Such a system has the potential to detect gross errors in HDR treatment delivery that could otherwise remain undetected.