title: The use of photogrammetry in tissue compensator design. Part I: photogrammetric determination of patient topography.
abstract: The surface topography of a patient can be determined by photogrammetry before beginning radiotherapy. The source light of the therapy unit or simulator is used to project a grid pattern onto the patient, and this is then photographed together with control points consisting of miniature light bulbs mounted on a frame suspended from the wedge slot of the therapy machine. When the photograph is projected onto a graphics terminal for data entry into a computer, the three-dimensional topography of the patient's surface can be reconstructed as a two-dimensional matrix of discrete points. A computer algorithm can then design a tissue compensator to fit the individual patient.
mesh_terms: D006801:Humans; D008433:Mathematics; D008953:Models, Anatomic; D010347:Patient Care Planning; D010780:Photogrammetry; D010781:Photography; D011879:Radiotherapy Dosage