TY - JOUR
T1 - The potential of an optical surface tracking system in non-coplanar single isocenter treatments of multiple brain metastases
AU - Swinnen, Ans C. C.
AU - Ollers, Michel C.
AU - Ong, Chin Loon
AU - Verhaegen, Frank
N1 - Funding Information:
This work has been performed in collaboration with C-RAD and Orfit Industries. Further, the authors like to thank the volunteers, who participated in this study.
Publisher Copyright:
© 2020 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.
PY - 2020/6
Y1 - 2020/6
N2 - To evaluate the accuracy of a commercial optical surface tracking (OST) system and to demonstrate how it can be implemented to monitor patient positioning during non-coplanar single isocenter stereotactic treatments of brain metastases. A 3-camera OST system was used (Catalyst HD (TM), C-RAD) on a TruebeamSTx with a 6DoF couch. The setup accuracy and agreement between the OST system, and CBCT and kV-MV imaging at couch angles 0 degrees and 270 degrees, respectively, were examined. Film measurements at 3 depths in the Rando-Alderson phantom were performed using a single isocenter non-coplanar VMAT plan containing 4 brain lesions. Setup of the phantom was performed with CBCT at couch 0 degrees and subsequently monitored by OST at other couch angles. Setup data for 7 volunteers were collected to evaluate the accuracy and reproducibility of the OST system at couch angles 0 degrees, 45 degrees, 90 degrees, 315 degrees, and 270 degrees. These results were also correlated to the couch rotation offsets obtained by a Winston-Lutz (WL) test. The Rando-Alderson phantom, as well as volunteers, were fixated using open face masks (Orfit). For repeated tests with the Rando-Alderson phantom, deviations between rotational and translational isocenter corrections for CBCT and OST systems are always within 0.2 degrees (pitch, roll, yaw), and 0.1mm and 0.5mm (longitudinal, lateral, vertical) for couch positions 0 degrees and 270 degrees, respectively. Dose deviations between the film and TPS doses in the center of the 4 lesions were -1.2%, -0.1%, -0.0%, and -1.9%. Local gamma evaluation criteria of 2%/2 mm and 3%/1 mm yielded pass rates of 99.2%, 99.2%, 98.6%, 89.9% and 98.8%, 97.5%, 81.7%, 78.1% for the 4 lesions. Regarding the volunteers, the mean translational and rotational isocenter shift values were (0.24 +/- 0.09) mm and (0.15 +/- 0.07) degrees. Largest isocenter shifts were found for couch angles 45 & x2da; and 90 & x2da;, confirmed by WL couch rotation offsets. Patient monitoring during non-coplanar VMAT treatments of brain metastases is feasible with submillimeter accuracy.
AB - To evaluate the accuracy of a commercial optical surface tracking (OST) system and to demonstrate how it can be implemented to monitor patient positioning during non-coplanar single isocenter stereotactic treatments of brain metastases. A 3-camera OST system was used (Catalyst HD (TM), C-RAD) on a TruebeamSTx with a 6DoF couch. The setup accuracy and agreement between the OST system, and CBCT and kV-MV imaging at couch angles 0 degrees and 270 degrees, respectively, were examined. Film measurements at 3 depths in the Rando-Alderson phantom were performed using a single isocenter non-coplanar VMAT plan containing 4 brain lesions. Setup of the phantom was performed with CBCT at couch 0 degrees and subsequently monitored by OST at other couch angles. Setup data for 7 volunteers were collected to evaluate the accuracy and reproducibility of the OST system at couch angles 0 degrees, 45 degrees, 90 degrees, 315 degrees, and 270 degrees. These results were also correlated to the couch rotation offsets obtained by a Winston-Lutz (WL) test. The Rando-Alderson phantom, as well as volunteers, were fixated using open face masks (Orfit). For repeated tests with the Rando-Alderson phantom, deviations between rotational and translational isocenter corrections for CBCT and OST systems are always within 0.2 degrees (pitch, roll, yaw), and 0.1mm and 0.5mm (longitudinal, lateral, vertical) for couch positions 0 degrees and 270 degrees, respectively. Dose deviations between the film and TPS doses in the center of the 4 lesions were -1.2%, -0.1%, -0.0%, and -1.9%. Local gamma evaluation criteria of 2%/2 mm and 3%/1 mm yielded pass rates of 99.2%, 99.2%, 98.6%, 89.9% and 98.8%, 97.5%, 81.7%, 78.1% for the 4 lesions. Regarding the volunteers, the mean translational and rotational isocenter shift values were (0.24 +/- 0.09) mm and (0.15 +/- 0.07) degrees. Largest isocenter shifts were found for couch angles 45 & x2da; and 90 & x2da;, confirmed by WL couch rotation offsets. Patient monitoring during non-coplanar VMAT treatments of brain metastases is feasible with submillimeter accuracy.
KW - brain metastases
KW - non-coplanar
KW - open face mask
KW - optical surface tracking
KW - stereotactic radiosurgery
KW - GUIDED STEREOTACTIC RADIOSURGERY
KW - BEAM COMPUTED-TOMOGRAPHY
KW - ACCURACY
KW - RADIOTHERAPY
KW - FRAMELESS
KW - GUIDANCE
KW - IMMOBILIZATION
KW - COINCIDENCE
KW - DELIVERY
KW - QUALITY
U2 - 10.1002/acm2.12866
DO - 10.1002/acm2.12866
M3 - Article
C2 - 32237274
SN - 1526-9914
VL - 21
SP - 63
EP - 72
JO - Journal of Applied Clinical Medical Physics
JF - Journal of Applied Clinical Medical Physics
IS - 6
ER -