Taha Hewala - Radiation Sciences Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
Mohamed Fahmy - Department of Radiation Therapy, Children Cancer Hospital ۵۷۳۵۷, Cairo, Egypt
Sanaa El-Benhawy - Radiation Sciences Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
Hany Ammar - Department of Radiation Therapy, Children Cancer Hospital ۵۷۳۵۷, Cairo, Egypt

Background: This study aims to evaluate the interchangeability between cone beam computed tomography (CBCT) and the optical surface scanning system (Catalyst) for daily positioning during radiation therapy in head and neck cancer patients.Method: This study was designed as a prospective observational descriptive study divided into two parts. The first part involved a phantom study using the computerized imaging reference systems (CIRS) child atom phantom. It aimed to detect deviations in patient position across six degrees of freedom (lateral, longitudinal, vertical, rotation, roll, and pitch) using the optical light scanner and Catalyst and compare them with deviations detected by CBCT in the same treatment sessions. The second part included ۲۵۲ sessions, during which ۳۰ head and neck cancer patients were treated at Children Cancer Hospital ۵۷۳۵۷, Egypt, using both Catalyst and CBCT for setup treatment positioning.Results: The differences between CBCT and Catalyst in all six degrees of deviation were not statistically significant (lateral (P = ۰.۱۷۵), longitudinal (P = ۰.۲۹۶), vertical (P = ۰.۱۱۰), rotation (P = ۰.۹۳۶), roll (P = ۰.۵۲۷), and pitch (P = ۰.۲۷۰)).Conclusion: The optical light scanner system Catalyst is comparable to CBCT. Surface scanning (Catalyst) has proven reliable and feasible for daily patient positioning, with the advantage of avoiding daily exposure to additional radiation.

Radiotherapy, Image-Guided, Cone-Beam Computed Tomography, Catalyst, Head and neck neoplasms