Room: Stars at Night Ballroom 2-3
Purpose: Live Cherenkov imaging of radiotherapy provides real-time treatment verification against the treatment plan. Rare misadministration and adverse events can occur during external beam radiotherapy, which introduces risks to patients including tissue damage or incomplete delivery. Cherenkov light emission caused by secondary particles moving faster than the phase velocity of light in tissue can be used to visualize the beam on the patient in real-time, and compared with the treatment plan.
Methods: Cherenkov light imaging of whole breast radiation therapy was performed in a clinical study to determine beam shape deviation from the treatment plan. Procedures were performed in compliance with IRB approval, with each patient consented. The Cherenkov camera system uses live background subtraction to image with room lights on, and was calibrated with the room isocenter, in order to allow for co-registration with the treatment planning system and CT information. The total accumulated Cherenkov image for each beam per patient was thresholded and compared with the expected beam profile from the treatment plan, using the metrics of mean distance to conformity (MDC â€“ representing the average distance of deviation in mm) and DICE coefficient (representing the percentage agreement in beam shape).
Results: Results are presented for a total of 100 fractions from 10 patients, with each fraction consisting of 2-4 beams. Beam shape was in close agreement with the treatment plan for all patients and beams, with a total mean DICE of 92.3% and MDC of 3.0 mm (standard deviation of 1.6 % and 0.9 mm respectively).
Conclusion: Live Cherenkov light imaging can provide verification of the beam on the patient in real-time. Beam shape comparison with the treatment plan can be used to catch deviations from the expected treatment delivery, thereby avoiding potential treatment delivery errors.
Funding Support, Disclosures, and Conflict of Interest: Michael Jermyn is an employee, Brian Pogue is a president, and William Ware is CEO of DoseOptics LLC.