title: Initial assessment of tumor tracking with a gimbaled linac system in clinical circumstances: a patient simulation study.
abstract: OBJECTIVE
  To have an initial assessment of the Vero Dynamic Tracking workflow in clinical circumstances and quantify the performance of the tracking system, a simulation study was set up on 5 lung and liver patients.
  
  
  METHODS
  The preparatory steps of a tumor tracking treatment, based on fiducial markers implanted in the tumor, were executed allowing pursuit of the tumor with the gimbaled linac and monitoring X-rays acquisition, however, without activating the 6 MV beam. Data were acquired on workflow time-efficiency, tracking accuracy and imaging exposure.
  
  
  RESULTS
  The average time between the patient entering the treatment room and the first treatment field was about 9 min. The time for building the correlation model was 3.2 min. Tracking errors of 0.55 and 0.95 mm (1σ) were observed in PAN/TILT direction and a 2D range of 3.08 mm. A skin dose was determined of 0.08 mGy/image, with a source-to-skin distance of 900 mm and kV exposure of 1 mAs. On average 1.8 mGy/min kV skin dose was observed for 1 Hz monitoring.
  
  
  CONCLUSIONS
  The Vero tracking solution proved to be fully functional and showed performance comparable with other real-time tracking systems.
authors: Radiotherapy Department, Vrije Universiteit Brussel, Brussel, Belgium. tom.depuydt@uzbrussel.be
authors: Tom
authors: T
authors: Depuydt
authors: Kenneth
authors: K
authors: Poels
authors: Dirk
authors: D
authors: Verellen
authors: Benedikt
authors: B
authors: Engels
authors: Christine
authors: C
authors: Collen
authors: Chloe
authors: C
authors: Haverbeke
authors: Thierry
authors: T
authors: Gevaert
authors: Nico
authors: N
authors: Buls
authors: Gert
authors: G
authors: Van Gompel
authors: Truus
authors: T
authors: Reynders
authors: Michael
authors: M
authors: Duchateau
authors: Koen
authors: K
authors: Tournel
authors: Marlies
authors: M
authors: Boussaer
authors: Femke
authors: F
authors: Steenbeke
authors: Frederik
authors: F
authors: Vandenbroucke
authors: Mark
authors: M
authors: De Ridder
mesh_terms: D057918:Fiducial Markers; D056973:Four-Dimensional Computed Tomography / Q000379:methods; D006801:Humans; D009068:Movement; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D016544:Patient Simulation; D061089:Radiotherapy, Image-Guided / Q000379:methods*