title: Biophysical characterization of a relativistic proton beam for image-guided radiosurgery.
abstract: We measured the physical and radiobiological characteristics of 1 GeV protons for possible applications in stereotactic radiosurgery (image-guided plateau-proton radiosurgery). A proton beam was accelerated at 1 GeV at the Brookhaven National Laboratory (Upton, NY) and a target in polymethyl methacrylate (PMMA) was used. Clonogenic survival was measured after exposures to 1-10 Gy in three mammalian cell lines. Measurements and simulations demonstrate that the lateral scattering of the beam is very small. The lateral dose profile was measured with or without the 20-cm plastic target, showing no significant differences up to 2 cm from the axis A large number of secondary swift protons are produced in the target and this leads to an increase of approximately 40% in the measured dose on the beam axis at 20 cm depth. The relative biological effectiveness at 10% survival level ranged between 1.0 and 1.2 on the beam axis, and was slightly higher off-axis. The very low lateral scattering of relativistic protons and the possibility of using online proton radiography during the treatment make them attractive for image-guided plateau (non-Bragg peak) stereotactic radiosurgery.
authors: Biophysics Department, GSI Helmholtz Center for Heavy Ions Research, Planckstraße 1, Darmstadt, Germany.
authors: Zhan
authors: Z
authors: Yu
authors: Marie
authors: M
authors: Vanstalle
authors: Chiara
authors: C
authors: La Tessa
authors: Guo-Liang
authors: GL
authors: Jiang
authors: Marco
authors: M
authors: Durante
mesh_terms: D001703:Biophysics / Q000379:methods*; D002460:Cell Line; D045744:Cell Line, Tumor; D003198:Computer Simulation; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D015233:Models, Statistical; D009010:Monte Carlo Method; D010315:Particle Accelerators; D010969:Plastics; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011522:Protons; D018787:Radiation Oncology / Q000379:methods; D016634:Radiosurgery / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000379:methods*
chemical_list: D010969:Plastics; D011522:Protons; D019904:Polymethyl Methacrylate