Author: Robert K Chin, Klea Hoxha, Erika Jank, Jesus Juarez, Eulanca Yuka Liu, Dylan P. O'Connell, X. Sharon Qi, Ricky R Savjani 👨🔬
Affiliation: Department of Radiation Oncology, University of California, Los Angeles, University of California, Los Angeles, UCLA Radiation Oncology 🌍
Purpose:
Daily cone beam CT (CBCT) images are acquired prior to each radiotherapy treatment for verifying patient positioning. HyperSight is an advanced imaging solution that replaces standard CBCT data with higher quality images, due to hardware and software upgrades. These scans also provide daily snapshots of internal anatomy, which can be used to monitor soft tissue changes throughout treatment. This study explores the use of state-of-the-art in-room imaging for improving the assessment of body composition and nutritional status for head and neck cancer patients undergoing radiotherapy.
Methods:
In this retrospective observational case report, images from radiation treatment were contoured using TotalSegmentator, an autosegmentation tool, to delineate soft tissue. The patient received standard CBCT imaging for the first 17 treatments, and HyperSight daily imaging for the remainder of treatment. The daily imaging data were visually assessed for image quality, and similarity metrics were computed from the resulting contours compared to the ground truth CT Simulation contours.
Results:
HyperSight scans appear to have less noise and artifacts than the CBCT’s, and overall image quality more similar to CT Simulation. Inconsistent autosegmentations on CBCT appear in areas of poor image quality, most notably on the inferior aspect. The Dice score of the skeletal muscle contour was 0.587 for HyperSight and 0.566 for CBCT, and was 0.707 and 0.680 for subcutaneous fat. The Hausdorff distance of skeletal muscle was 23.77 and 29.37 mm for HyperSight and CBCT, and was 27.52 and 30.46 mm for subcutaneous fat.
Conclusion:
Advanced daily imaging technology produces higher quality data, contributing to better soft tissue contrast and improved performance of autosegmentation models. Soft tissue contours on daily imaging enable robust tracking of body composition changes over time. HyperSight is a non-invasive tool that can improve the monitoring of nutritional status of head and neck cancer patients undergoing radiotherapy.