Characterization of the IDENTIFY(TM) surface scanning system for radiation therapy setup on a closed-bore linac
Publication year
2024Source
Journal of Applied Clinical Medical Physics, 25, 4, (2024), pp. e14326, article e14326ISSN
Publication type
Article / Letter to editor
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Organization
Radiation Oncology
Journal title
Journal of Applied Clinical Medical Physics
Volume
vol. 25
Issue
iss. 4
Page start
p. e14326
Subject
Radiation Oncology - Radboud University Medical CenterAbstract
PURPOSE: In radiation therapy, surface guidance can be used for patient setup and intra-fraction motion monitoring. The surface guided radiation therapy (SGRT) system from Varian Medical systems, IDENTIFY(TM) , consists of three pods, including cameras and a random pattern projector, mounted on the ceiling. The information captured by the cameras is used to make a reconstruction of the surface. The aim of the study was to assess the technical performance of this SGRT system on a closed-bore linac. METHODS: Phantom measurements were performed to assess the accuracy, precision, reproducibility and temporal stability of the system, both in align and in load position. Translations of the phantoms in lateral, longitudinal, and vertical direction, and rotations around three axes (pitch, roll and yaw) were performed with an accurate, in-house built, positioning stage. Different phantom geometries and different surface colors were used, and various ambient light intensities were tested. RESULTS: The accuracy of the IDENTIFY(TM) system at the closed-bore linac was 0.07 mm and 0.07 degrees at load position, and 0.06 mm and 0.01 degrees at align position for the white head phantom. The precision was 0.02 mm and 0.02 degrees in load position, and 0.01 mm and 0.02 degrees in align position. The accuracy for the Penta-Guide phantom was comparable to the white head phantom, with 0.06 mm and 0.01 degrees in align position. The system was slightly less accurate for translations of the CIRS lung phantom in align position (0.20 mm, 0.05 degrees). Reproducibility measurements showed a variation of 0.02 mm in load position. Regarding the temporal stability, the maximum drift over 30 min was 0.33 mm and 0.02 degrees in load position. No effect of ambient light level on the accuracy of the IDENTIFY(TM) system was observed. Regarding different surface colors, the accuracy of the system for a black phantom was slightly worse compared to a white surface, but not clinical relevant. CONCLUSION: The IDENTIFY(TM) system can adequately be used for motion monitoring on a closed-bore linac with submillimeter accuracy. The results of the performed measurements meet the clinical requirements described in the guidelines of the AAPM and the ESTRO.
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- Academic publications [245055]
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- Faculty of Medical Sciences [93207]
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