title: Clinical results of computerized tomography-based simulation with laser patient marking.
abstract: OBJECTIVE
  Accuracy of a patient treatment portal marking device and computerized tomography (CT) simulation have been clinically tested.
  
  
  METHODS
  A CT-based simulator has been assembled based on a commercial CT scanner. This includes visualization software and a computer-controlled laser drawing device. This laser drawing device is used to transfer the setup, central axis, and/or radiation portals from the CT simulator to the patient for appropriate patient skin marking. A protocol for clinical testing is reported. Twenty-five prospectively, sequentially accessioned patients have been analyzed.
  
  
  RESULTS
  The simulation process can be completed in an average time of 62 min. Under many cases, the treatment portals can be designed and the patient marked in one session. Mechanical accuracy of the system was found to be within +/- 1mm. The portal projection accuracy in clinical cases is observed to be better than +/- 1.2 mm. Operating costs are equivalent to the conventional simulation process it replaces.
  
  
  CONCLUSIONS
  Computed tomography simulation is a clinical accurate substitute for conventional simulation when used with an appropriate patient marking system and digitally reconstructed radiographs. Personnel time spent in CT simulation is equivalent to time in conventional simulation.
authors.affiliation: Radiation Oncology Department, Wayne State University, Detroit, MI 48201, USA.
authors.forename: D P
authors.initials: DP
authors.lastname: Ragan
authors.forename: J D
authors.initials: JD
authors.lastname: Forman
authors.forename: T
authors.initials: T
authors.lastname: He
authors.forename: C F
authors.initials: CF
authors.lastname: Mesina
mesh_terms: D003198:Computer Simulation; D006801:Humans; D007834:Lasers; D008297:Male; D009369:Neoplasms / Q000532:radiotherapy*; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*