Author: Petr Bruza, Alexander Geiersbach, David J. Gladstone, Lesley A Jarvis, Allison Matous 👨🔬
Affiliation: Thayer School of Engineering, Dartmouth College, Dartmouth Cancer Center, Dartmouth Health 🌍
Purpose: During external beam radiation therapy, couch kicks are often necessary to achieve effective treatments, yet they make interpreting Cherenkov images much more challenging. We present a surface-based solution to this problem by mapping each field onto the patient surface CT, allowing clinics to view all fields on a stationary patient.
Methods: Cherenkov images were preprocessed to separate each treatment field and raycasting was utilized to project each Cherenkov image onto the corresponding rotated patient surface. Multiple Cherenkov camera angles were combined to provide sufficient patient surface coverage. A composite patient surface was reconstructed with the patient at isocenter and with zero couch rotation. To verify accuracy, a standard plan was delivered to an anatomical Annie phantom with scintillator dots present to verify spatial accuracy of the projection algorithm. Several patient datasets were analyzed using the raycasting correction.
Results: Cherenkov images were successfully mapped to the patient surfaces in both the phantom test and clinical cases. Reconstruction made clinical treatment monitoring significantly easier for clinical staff.
Conclusion: This proof-of-concept study demonstrates an efficient method to improve clinical workflow and patient safety by eliminating couch kicks as a variable in Cherenkov imaging. Therapists and physicians no longer need to spend valuable time attempting to interpret rotated images, and instead can immediately review patient treatments from a natural and intuitive point of view.