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Session: Multi-Disciplinary General ePoster Viewing [Return to Session]

Surface Guided Imaging Versus Orthogonal X-Ray Imaging for Initial Setup and Position Verification at Couch Angles with An Anthropomorphic Head Phantom

K Rasmussen*, V Bry, D Saenz, M Bonnen, N Papanikolaou, University of Texas HSC SA, San Antonio, TX


PO-GePV-M-220 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: To evaluate positioning accuracy of C-RAD Catalyst HD for initial (180o) setup using multiple reference images and position verification at non-coplanar couch angles compared to Brainlab Exactrac for two different isocenter locations.

Methods: A Brainlab phantom was CT scanned and a reference image was acquired using the C-RAD Sentinel system. A treatment plan was generated using Brainlab’s iPlan (Munich, Germany) Treatment Planning Software with arcs at couch angles (270°, 225°, 180°, 135°, and 90°) and isocenters were placed in the frontal and occipital regions of the brain. Test 1: Phantom positioning was quantified based on discrepancies with x-ray imaging for two different reference images (1) DICOM surface rendered image generated based on the CT scan in the TPS and (2) Sentinel scan acquired at CT simulation.Test 2: A new reference image was acquired by the C-RAD Catalyst HD system, and the treatment couch was rotated from initial couch angle (180°) to non-coplanar couch angles (270°, 225°, 135°, and 90°). Positional shift discrepancies were calculated between Brainlab Exactrac and CRAD Catalyst HD system when positioning the phantom for the frontal and occipital isocenters.

Results: Reference images demonstrated ≤0.63mm discrepancy in each translational direction for initial setup using C-RAD. Discrepancies between Brainlab Exactrac and C-RAD Catalyst HD remained <1mm for each translational direction.

Conclusion: Sub-millimeter accuracy of 3D surface reference images for initial setup as well as comparable accuracy between Brainlab Exactrac and C-RAD Catalyst HD for position verification at non-coplanar couch angles using an anthropomorphic head phantom was demonstrated.

Funding Support, Disclosures, and Conflict of Interest: This research was funded in part by C-RAD, the Cancer Prevention and Research Institute of Texas (CPRIT) Research Training Award Number RP170345 and the National Center for Advancing Translational Sciences (NCATS) of the National Institutes of Health (NIH) under Award Number TL1TR002647.


Not Applicable / None Entered.


TH- External Beam- Photons: General (most aspects)

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