Design of a novel 5-camera surface guidance system with multiple imaging isocenters. J Appl Clin Med Phys 2022 Oct;23(10):e13750
Date
08/11/2022Pubmed ID
35946854Pubmed Central ID
PMC9588261DOI
10.1002/acm2.13750Scopus ID
2-s2.0-85135604278 (requires institutional sign-in at Scopus site) 1 CitationAbstract
PURPOSE/OBJECTIVE(S): Surface-guided radiation therapy (SGRT) can track the patient surface noninvasively to complement radiographic image-guided radiation therapy with a standard 3-camera system and a single radiation/image isocenter. Here we report the commissioning of a novel SGRT system that monitors three imaging isocenters locations in a proton half-gantry room with a unique 5-camera configuration.
MATERIALS/METHODS: The proton half-gantry room has three image isocenters, designated ISO-0, ISO-1, and ISO-2, to cover various anatomical sites via a robotic ceiling-mounted cone-beam CT. Although ISO-0 and ISO-1 are used to image the cranium, head and neck, and thoracic regions, ISO-2 is often used to image body and extremity sites and contiguous craniospinal target volumes. The five-camera system was calibrated to the radiographic isocenter by using a stereotactic radiosurgery cube phantom for each image isocenter.
RESULTS: The performance of this 5-camera system was evaluated for 6 degrees of freedom in three categories: (1) absolute setup accuracy relative to the radiographic kV image isocenter based on the DICOM reference; (2) relative shift accuracy based on a reference surface capture; and (3) isocenter tracking accuracy from one isocenter to another based on a reference surface capture. The evaluation revealed maximum deviations of 0.8, 0.2, and 0.6 mm in translation and 0.2°, 0.1°, and 0.1° in rotation for the first, second, and third categories, respectively. Comparing the dosimetry and latency with static and gated irradiation revealed a 0.1% dose difference and positional differences of 0.8 mm in X and 0.9 mm in Y with less than 50 ms temporal accuracy.
CONCLUSION: The unique 5-camera system configuration provides SGRT at the treatment isocenter (ISO-0) and also imaging isocenter locations (ISO-0, ISO-1, and ISO-2) to ensure correct patient positioning before and after radiographic imaging, especially during transitions from the offset imaging isocenters to the treatment isocenter.
Author List
Ates O, Zhao L, Sobczak D, Pirlepesov F, Hua CH, Waghorn B, Merchant TEAuthor
Li Zhao PhD Associate Professor in the Radiation Oncology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Cone-Beam Computed TomographyHumans
Patient Positioning
Phantoms, Imaging
Protons
Radiotherapy, Image-Guided
