title: A fast algorithm for the dose calculation of irregularly shaped fields in stereotactic convergent beam irradiation.
abstract: A fast, irregular field dose calculation algorithm is described for use in stereotactic convergent beam irradiation (CBI) with high-energy photons. The dose distribution of an irregular field is approximated by a convolution of narrow pencil beams. Decomposition of pencil beams and a 'pre-selection' algorithm is used to avoid redundant calculations. A typical dose calculation for CBI with nine couch angles and nine different irregularly shaped fields takes less than 90 s on a DEC VAXstation 3100. Fortran. The difference between the measured and the calculated dose values increases with increasing distance from the isocentre. The error in 10% isodose line is less than 3% of the isocentre dose.
authors.affiliation: Deutsches Krebsforschungszentrum, Abteilung Medizinische Physik, Heidelberg, Germany.
authors.forename: K U
authors.initials: KU
authors.lastname: Gardey
authors.forename: T
authors.initials: T
authors.lastname: Bortfeld
authors.forename: W
authors.initials: W
authors.lastname: Schlegel
authors.forename: B
authors.initials: B
authors.lastname: Rhein
mesh_terms: D000465:Algorithms; D006801:Humans; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted; D015203:Reproducibility of Results; D013238:Stereotaxic Techniques