Open AccessSurface guided imaging during stereotactic radiosurgery with automated delivery
Author(s) -
Covington Elizabeth L.,
Stanley Dennis N.,
Fiveash John B.,
Thomas Evan M.,
Marcrom Samuel R.,
Bredel Marcus,
Willey Christopher D.,
Riley Kristen O.,
Popple Richard A.
Publication year - 2020
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.13066
Subject(s) - radiosurgery , medicine , nuclear medicine , medical imaging , radiation therapy , biomedical engineering , radiology
Purpose To report on the use of surface guided imaging during frameless intracranial stereotactic radiotherapy with automated delivery via HyperArc TM (Varian Medical Systems, Palo Alto, CA). Methods All patients received intracranial radiotherapy with HyperArc TM and were monitored for intrafraction motion by the AlignRT® (VisionRT, London, UK) surface imaging (SI) system. Immobilization was with the Encompass TM (Qfix, Avondale, PA) aquaplast mask device. AlignRT® log files were correlated with trajectory log files to correlate treatment parameters with SI reported offsets. SI reported offsets were correlated with gantry angle and analyzed for performance issues at non‐zero couch angles and during camera‐pod blockage during gantry motion. Demographics in the treatment management system were used to identify race and determine if differences in SI reported offsets are due to skin tone settings. Results A total of 981 fractions were monitored over 14 months and 819 were analyzed. The median AlignRT® reported motion from beginning to the end of treatment was 0.24 mm. The median offset before beam on at non‐zero couch angles was 0.55 mm. During gantry motion when camera pods are blocked, the median magnitude was below 1 mm. Median magnitude of offsets at non‐zero couch angles was not found to be significantly different for patients stratified by race. Conclusions Surface image guidance is a viable alternative to scheduled mid‐treatment imaging for monitoring intrafraction motion during stereotactic radiosurgery with automated delivery.