title: Monte Carlo dose calculations for dynamic IMRT treatments.
abstract: Dose calculations for intensity modulated radiation therapy (IMRT) face new challenges due to the complex leaf geometry and time dependent nature of the delivery. A fast method of particle transport through a dynamic multileaf collimator (MLC) geometry that accounts for photon attenuation and first-scattered Compton photon production has been incorporated into an existing Monte Carlo code used for patient dose calculations. Dosimetric agreement between calculation and measurement for two photon energies and MLC types is within experimental error for the sliding window tests. For a patient IMRT field, the Monte Carlo calculations are closer to measured dose than similar superposition or pencil beam calculations.
authors.affiliation: Department of Radiation Oncology, Medical College of Virginia Hospitals at Virginia Commonwealth University, Richmond, USA. pjkeall@vcu.edu
authors.forename: P J
authors.initials: PJ
authors.lastname: Keall
authors.forename: J V
authors.initials: JV
authors.lastname: Siebers
authors.forename: M
authors.initials: M
authors.lastname: Arnfield
authors.forename: J O
authors.initials: JO
authors.lastname: Kim
authors.forename: R
authors.initials: R
authors.lastname: Mohan
mesh_terms: D006801:Humans; D008962:Models, Theoretical; D009010:Monte Carlo Method; D017785:Photons; D011336:Probability; D011874:Radiometry / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000295:instrumentation* / Q000379:methods*; D013997:Time Factors