S1626
Physics - Detectors, dose measurement and phantoms
ESTRO 2026
geometrical control, advanced imaging techniques, and by leveraging novel methods based on the photopolymerization process. Later, the system was used to characterize proton beams of three different energies, E1 =244.1MeV, E2 =208.8MeV, and E3 =162.8 MeV, with a beam diameter of ~3 mm delivered by utilizing proton beam facilities at PSI, Switzerland. Dose rates of DR1 = 1.7 Gy/s, DR2 =0.56 Gy/s, and DR3 =0.30 Gy/s were systematically investigated to assess the feasibility of the device for real-time proton beam characterization. For each irradiation, the total delivered dose was maintained at up to 30 Gy, with measurements repeated 3 times to validate reproducibility. Reference dosimetry with microDiamond P22197 was conducted to assess the performance of the detection system, enabling comparison across different measurements. Results: The detection system with a sensitive volume of 1.5 x 10-5 mm3 demonstrated excellent linear behavior (R12= 1, R22 = 1, and R32= 0.998) for three different proton energies and at the investigated dose rates. Standard deviation remains within 0.5% of the scintillating signal magnitude, and no Cerenkov signal was monitored in the given situation with different dose rates. Scintillating stability at the highest energy was found to be less than 0.6%, with an afterglow of less than 0.85% of the total output signal. The measurement was found to be acceptable when compared with the results obtained using the reference dosimeter and the MC simulation. The detection system enabled high spatial resolution measurements, owing to its high signal-to-noise ratio for mini proton beams, while maintaining positional uncertainty below 1%. Conclusion: The proposed new-generation miniature scintillating system demonstrated its feasibility and potential applicability for real-time high-energy proton beam dosimetry, with high sensitivity and high spatial resolution at clinically relevant energies. The measurement results suggested that the system holds promise for dose and dose-rate verification with high- energy proton mini-beams. References: [1] Beaulieu, Luc, and Sam Beddar. "Review of plastic and liquid scintillation dosimetry for photon, electron, and proton therapy." Physics in Medicine & Biology 61.20 (2016): R305[2] Debnath, Sree Bash Chandra, et al. "High spatial resolution inorganic scintillator detector for high ‑ energy X ‑ ray beam at small field irradiation." Medical Physics 47.3 (2020): 1364-1371.[3] Alharbi, Majed, et al. "Benchmarking a novel inorganic scintillation detector for applications in radiation therapy." Physica Medica 68 (2019): 124-131. Keywords: scintillating detector, proton mini-beam dosimetry
Proffered Paper 306
Clinical Implementation and Impact of Real-Time Cherenkov Imaging for Treatment Verification and Patient Safety in Radiation Therapy Adi Robinson 1 , Michael Tallhamer 2 1 Radiation Oncolgy, AdventHealth, Celebration, USA. 2 Radiation Oncolgy, AdventHealth, Parker, USA Purpose/Objective: Cherenkov imaging (CI) enables real-time visualization of radiation delivery by capturing optical emissions generated when charged particles exceed the phase velocity of light in tissue. This study evaluates the clinical utility of CI across diverse treatment sites, focusing on its ability to enhance treatment verification, patient safety, and workflow efficiency. Material/Methods: CI was implemented using two commercially available systems—BeamSite (DoseOptics LLC) and DoseRT (VisionRT)—on Varian TrueBeam and Elekta Versa HD linear accelerators. Time-gated cameras synchronized with the beam pulses were used to capture Cherenkov light emission from the patient surface during treatment. Data were collected under IRB-approved protocols across multiple disease sites. CI images were analyzed qualitatively and semi-quantitatively by therapists, physicists, and physicians for treatment verification, positional accuracy, and unintended dose visualization. Deviations were correlated with treatment plans and patient positioning data from surface-guided radiation therapy (SGRT). Results: CI produced clear, high-contrast visualizations of treatment fields in all cases without disrupting clinical workflow. Across the cohort, Cherenkov feedback led to corrective actions in 15% of monitored fractions, including immediate detection of unintended dose to contralateral breast, limbs, or previously treated regions. Examples included identification of exit dose to the face during breast/arm irradiation, field overlap in the axilla, and incorrect port film technique in DIBH treatments. CI confirmed absence of dose in sensitive or previously irradiated areas (e.g., contralateral limb sparing in sarcoma). The technology also aided in patient education, real-time correction of setup errors, and informed adjustments to SGRT tolerance thresholds. No increase in treatment time was observed. Conclusion: Cherenkov imaging provides a unique, non-invasive method for real-time verification of dose delivery and treatment geometry, complementing existing QA and imaging modalities. Its clinical deployment has improved treatment accuracy, patient safety, and staff confidence while revealing opportunities for workflow refinement. Broader implementation and quantitative
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