title: Accuracy of single-session extracranial radiotherapy for simple shaped lung tumor or metastasis using fast 3-D CT treatment planning.
abstract: BACKGROUND
  This study is situated in the area of measuring set-up accuracy and time periods of single-session extracranial radiotherapy (SSRT) for simple-shaped targets (e.g., spherical or rotational symmetrical) definitively located in the peripheral lung.
  
  
  METHODS
  After adaptation of the stereotactic body frame, the patient has to remain in the vacuum pillow during planning computed tomography (CT), fast three-dimensional (3-D) treatment planning, and direct irradiation after verification. Fast preplanning is performed by using virtual simulation software to accelerate the method.
  
  
  RESULTS
  In our new procedure, SSRT is applied in approximately 1.5 h. The mean setup accuracy vector was 2.4+/-0.7 mm in the range of 1.34 to 4 mm. Mean intrafractional patient movement in the stereotactic body frame before and after radiation was 0.70 mm+/-0.5 mm and 0.76+/-0.76 mm in the range of 0 to 2.8 mm. Mean time period steps were measured at (1) planning CT with 3-D treatment planning: 76+/-12 min; (2) irradiation and verification: 33+/-7 min; and (3) complete procedure duration: 109+/-11 min (range, 89-169).
  
  
  CONCLUSIONS
  The main difference between the positioning technique of SSRT and that of conventional extracranial radiosurgery is the tighter patient fixation, which guarantees minimal patient movement. The main advantages are procedure acceleration and omission of CT simulation. SSRT is a preliminary stage of real-time treatment.
authors.affiliation: Department of Radiation Oncology, University of Marburg, Marburg, Germany. strassma@med.uni-marburg.de
authors.forename: Gerd
authors.initials: G
authors.lastname: Strassmann
authors.forename: Isabell
authors.initials: I
authors.lastname: Braun
authors.forename: Oliver
authors.initials: O
authors.lastname: Kress
authors.forename: Detlef
authors.initials: D
authors.lastname: Richter
authors.forename: Hans Otto
authors.initials: HO
authors.lastname: Neidel
authors.forename: Klaus Jochen
authors.initials: KJ
authors.lastname: Klose
authors.forename: Hanxiang
authors.initials: H
authors.lastname: An
authors.forename: Birgit
authors.initials: B
authors.lastname: Vogel
authors.forename: Frank
authors.initials: F
authors.lastname: Rose
authors.forename: Rita
authors.initials: R
authors.lastname: Engenhart-Cabillic
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000532:radiotherapy* / Q000556:secondary; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007103:Immobilization / Q000379:methods; D008175:Lung Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed