Author: Michelle Alonso-Basanta, Carl Denis, Wenbo Gu, Xinmin Liu, Ahmad Sakaamini, Rodney D. Wiersma 👨🔬
Affiliation: UCLA, University of Pennsylvania, CDR Systems 🌍
Purpose: Stereotactic radiosurgery (SRS) is a non-invasive technique used to treat functional abnormalities and small brain tumors. Traditional SRS relies on a rigidly fixed metal head ring, causing discomfort, inconvenience, and invasive procedures that can deter patients and reduce clinical efficiency. Attempts to eliminate the frame with thermoplastic face masks have led to decreased accuracy due to mask flex, manufacturing quality, and patient-specific changes. To address these limitations, we present a novel robotic head motion compensation (RHMC) device for SRS that eliminates the need for a frame or mask.
Methods: A compact RHMC device was developed as a portable accessory for easy attachment and detachment from the Linac treatment table. Real-time six-dimensional (6D) head position tracking was achieved using 3D surface imaging, integrated into the robot control computer. Simulated SRS treatments were conducted with both phantom models and 20 human volunteers, without using the treatment beam.
Results: The extended platform hexapod design enabled 360-degree gantry rotation around the volunteers without collisions. Out of 20 volunteers, 2 were excluded due to incompatibility with the RHMC device. For the remaining 18, the RHMC system maintained head motion within a 1.0 mm and 0.5-degree threshold for 99% of the treatment time for a mock mid-brain lobe target, compared to only 45% without robotic compensation.
Conclusion: This study demonstrates the feasibility of frameless and maskless SRS with a novel RHMC system. By continuously tracking and compensating for patient head motion in real-time, the RHMC system has the potential to significantly improve patient comfort and streamline the SRS workflow while maintaining the high level of accuracy typically associated with frame-based techniques.