Purpose: Analysis of intrafraction motion in patients with intracranial targets treated with frameless, mask based stereotactic radiosurgery / radiotherapy using standard couch and 6D-skull tracking on CyberKnife. Materials and methods: Twenty-seven treatment datasets of fifteen patients were analyzed. For each sequential pair of images, the correction to the target position (position "offset") in six-degrees of motion was obtained. These offsets were used to calculate intrafraction shifts, and their statistical distribution. PTV margins were calculated, based on Van Herk formula. Results: The mean ± 1 SD intrafraction translationals were 0.27±0.61mm in left-right, 0.24±0.62mm in antero-posterior and 0.14±0.24mm in supero-inferior direction, and rotations were 0.13±0.21 degrees roll, 0.18±0.25 degrees pitch and 0.28±0.44 degrees yaw. Most intrafraction shifts were ≤ 1mm and 1 degree. Fourteen instances of intrafraction shifts exceeding the robotic correction threshold were noted. Calculated PTV margins were 1mm, 1mm and 0.4mm for for left-right, antero-posterior and supero-inferior directions, respectively. Conclusions: CyberKnife 6D-skull tracking with 1mm PTV margin effectively compensates for intrafraction motion. The occasional large intrafraction movements may assume significance for techniques not employing intrafraction motion management.
Purpose: Analysis of intrafraction motion in patients with intracranial targets treated with frameless, mask based stereotactic radiosurgery / radiotherapy using standard couch and 6D-skull tracking on CyberKnife. Materials and methods: Twenty-seven treatment datasets of fifteen patients were analyzed. For each sequential pair of images, the correction to the target position (position "offset") in six-degrees of motion was obtained. These offsets were used to calculate intrafraction shifts, and their statistical distribution. PTV margins were calculated, based on Van Herk formula. Results: The mean ± 1 SD intrafraction translationals were 0.27±0.61mm in left-right, 0.24±0.62mm in antero-posterior and 0.14±0.24mm in supero-inferior direction, and rotations were 0.13±0.21 degrees roll, 0.18±0.25 degrees pitch and 0.28±0.44 degrees yaw. Most intrafraction shifts were ≤ 1mm and 1 degree. Fourteen instances of intrafraction shifts exceeding the robotic correction threshold were noted. Calculated PTV margins were 1mm, 1mm and 0.4mm for for left-right, antero-posterior and supero-inferior directions, respectively. Conclusions: CyberKnife 6D-skull tracking with 1mm PTV margin effectively compensates for intrafraction motion. The occasional large intrafraction movements may assume significance for techniques not employing intrafraction motion management.
Authors: J C Flickinger; D Kondziolka; L D Lunsford; A Kassam; L K Phuong; R Liscak; B Pollock Journal: Int J Radiat Oncol Biol Phys Date: 2000-03-15 Impact factor: 7.038
Authors: Martin J Murphy; Steven D Chang; Iris C Gibbs; Quynh-Thu Le; Jenny Hai; Daniel Kim; David P Martin; John R Adler Journal: Int J Radiat Oncol Biol Phys Date: 2003-04-01 Impact factor: 7.038
Authors: Mischa S Hoogeman; Joost J Nuyttens; Peter C Levendag; Ben J M Heijmen Journal: Int J Radiat Oncol Biol Phys Date: 2007-11-08 Impact factor: 7.038
Authors: Maria-Lisa Wilhelm; Mark K H Chan; Benedikt Abel; Florian Cremers; Frank-Andre Siebert; Stefan Wurster; David Krug; Robert Wolff; Jürgen Dunst; Guido Hildebrandt; Achim Schweikard; Dirk Rades; Floris Ernst; Oliver Blanck Journal: Strahlenther Onkol Date: 2020-06-25 Impact factor: 3.621