title: Monte carlo simulation of an X-ray pixel beam microirradiation system.
abstract: Monte Carlo simulations are used in the development of a nanotechnology-based multi-pixel beam array small animal microirradiation system. The microirradiation system uses carbon nanotube field emission technology to generate arrays of individually controllable X-ray pixel beams that electronically form irregular irradiation fields having intensity and temporal modulation without any mechanical motion. The microirradiation system, once developed, will be incorporated with the micro-CT system already developed that is based on the same nanotechnology to form an integrated image-guided and intensity-modulated microirradiation system for high-temporal-resolution small animal research. Prospective microirradiation designs were evaluated based on dosimetry calculated using EGSnrc-based Monte Carlo simulations. Design aspects studied included X-ray anode design, collimator design, and dosimetric considerations such as beam energy, dose rate, inhomogeneity correction, and the microirradiation treatment planning strategies. The dosimetric properties of beam energies between 80-400 kVp with varying filtration were studied, producing a pixel beam dose rate per current of 0.35-13 Gy per min per mA at the microirradiation isocenter. Using opposing multi-pixel-beam array pairs reduces the dose inhomogeneity between adjacent pixel beams to negligible levels near the isocenter and 20% near the mouse surface.
authors.affiliation: Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina 27599, USA. erics@med.unc.edu
authors.forename: E C
authors.initials: EC
authors.lastname: Schreiber
authors.forename: S X
authors.initials: SX
authors.lastname: Chang
mesh_terms: D000818:Animals; D004566:Electrodes; D005240:Feasibility Studies; D006801:Humans; D051379:Mice; D009010:Monte Carlo Method; D037742:Nanotubes, Carbon; D009369:Neoplasms / Q000473:pathology / Q000532:radiotherapy; D019047:Phantoms, Imaging; D011874:Radiometry; D011879:Radiotherapy Dosage; D014964:X-Ray Therapy / Q000295:instrumentation / Q000379:methods*
chemical_list: D037742:Nanotubes, Carbon