Multi-Institutional Validation of a Smartphone-Based Surface Guided Radiation Therapy (SGRT) Tracking System for Respiratory Monitoring in Radiation Therapy

Abstract

<h3>Purpose/Objective(s)</h3> Surface guidance radiation therapy (SGRT) systems are becoming standard-of-care for patient setup and motion monitoring. However, commercial systems remain inaccessible to resource-limited clinics around the world. The iOS Surface Audiovisual Biofeedback (iSAVB) system implements ubiquitous mobile technology as a versatile tool for surface imaging in resource-strapped clinics. The purpose of this study is to establish a robust validation platform, commission iSAVB at multiple participating institutions, and validate iSAVB using phantom motion and against commercial systems during patient treatments. <h3>Materials/Methods</h3> Three participating institutions are implementing, validating, and comparing the iSAVB system against current clinical SGRT systems. The iSAVB system consists of depth camera enabled iOS device, to acquire real-time point-cloud data for surface rendering, a 3D printed stand capable of mounting and indexing on a treatment couch, and aa tablet (or external workstation) for audio-visual feedback and signal processing. Validation of the iSAVB system was performed against commercial optical systems at each center using a respiratory motion phantom. Motion traces were analyzed using linear regressions and Bland-Altman analysis. <h3>Results</h3> The iSAVB system was successfully installed at an initial institution and tested on phantoms and healthy volunteers. For free-breathing traces, iSAVB was significantly correlated to phantom input motion (r=0.99, p<0.0001; bias=0.00±0.05cm, 95%CI=−0.1cm,0.1cm) and commercial system motion (r=0.99, p<0.0001; bias=0.00±0.07cm, 95%CI=−0.14cm,0.14cm). Systems are currently being installed at the two additional institutions that will perform similar commissioning and validation. <h3>Conclusion</h3> A multi-center validation shows the iSAVB system can be used for surface motion monitoring and provides SGRT capabilities similar to current high-end clinical systems. The iSAVB system can be used for 3D/IMRT/VMAT treatments, although future validation is required for SBRT treatments. Future work includes establishing reliable commissioning protocols that follow TG-302 guidelines for resource-strapped departments to benefit from affordable and accurate surface imaging guidance. Reference: