title: Retrospective reconstruction of three-dimensional radiotherapy treatment plans of the thorax from two dimensional planning data.
abstract: OBJECTIVE
  A method for the retrospective reconstruction of three-dimensional (3-D) radiotherapy treatment plans from two-dimensional (2-D) planning data is detailed in this paper.
  
  
  METHODS
  With these techniques the user can register an arbitrarily shaped portal on a simulation film with a diagnostic computed tomography study of the patient and then generate the resultant 3-D dose distribution or dose-volume histogram. Seven treatment plans were reconstructed of patients who had previously undergone 3-D treatment planning for fields involving the thorax and who had had a diagnostic computed tomography (CT) scan. The dose-volume histograms and the spatial positions of the beams on the reconstructed plans were then compared to those of the original 3-D plan, which until then, were not made available to the investigators.
  
  
  RESULTS
  The dose-volume histograms of the reconstructed plans did not differ from those of the original plans by more than 3% except in the low dose region. The error in positioning the beam in the reconstructed plan was determined to be approximately 5 mm.
  
  
  CONCLUSIONS
  The technique of 3-D treatment plan reconstruction can be used, through retrospective studies, to obtain better assessments of normal tissue complication probabilities and tumor control probabilities.
authors.affiliation: Department of Biomedical Engineering, University of North Carolina at Chapel Hill.
authors.forename: A A
authors.initials: AA
authors.lastname: Boxwala
authors.forename: J G
authors.initials: JG
authors.lastname: Rosenman
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D011879:Radiotherapy Dosage; D011881:Radiotherapy, Computer-Assisted; D013899:Thoracic Neoplasms / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed