V E Bellinzona1, M Ciocca2, A Embriaco3, A Fontana4, A Mairani2, M Mori5, K Parodi6. 1. Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy; Dipartimento di Fisica, Università di Pavia, Pavia, Italy; Department of Medical Physics, Ludwig Maximilians University, Munich, Germany. 2. Medical Physics Unit, Centro Nazionale di Adroterapia Oncologica, Pavia, Italy. 3. Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy; Dipartimento di Fisica, Università di Pavia, Pavia, Italy. 4. Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy. Electronic address: andrea.fontana@pv.infn.it. 5. Dipartimento di Fisica, Università di Pavia, Pavia, Italy. 6. Department of Medical Physics, Ludwig Maximilians University, Munich, Germany; Heidelberg Ion Beam Therapy Center, University Hospital Heidelberg, Heidelberg, Germany.
Abstract
PURPOSE: The accurate evaluation of the lateral dose profile is an important issue in the field of proton radiation therapy. The beam spread, due to Multiple Coulomb Scattering (MCS), is described by the Molière's theory. To take into account also the contribution of nuclear interactions, modern Treatment Planning Systems (TPSs) generally approximate the dose profiles by a sum of Gaussian functions. In this paper we have compared different parametrizations for the lateral dose profile of protons in water for therapeutical energies: the goal is to improve the performances of the actual treatment planning. METHODS: We have simulated typical dose profiles at the CNAO (Centro Nazionale di Adroterapia Oncologica) beamline with the FLUKA code and validated them with data taken at CNAO considering different energies and depths. We then performed best fits of the lateral dose profiles for different functions using ROOT and MINUIT. RESULTS: The accuracy of the best fits was analyzed by evaluating the reduced χ(2), the number of free parameters of the functions and the calculation time. The best results were obtained with the triple Gaussian and double Gaussian Lorentz-Cauchy functions which have 6 parameters, but good results were also obtained with the so called Gauss-Rutherford function which has only 4 parameters. CONCLUSIONS: The comparison of the studied functions with accurate and validated Monte Carlo calculations and with experimental data from CNAO lead us to propose an original parametrization, the Gauss-Rutherford function, to describe the lateral dose profiles of proton beams.
PURPOSE: The accurate evaluation of the lateral dose profile is an important issue in the field of proton radiation therapy. The beam spread, due to Multiple Coulomb Scattering (MCS), is described by the Molière's theory. To take into account also the contribution of nuclear interactions, modern Treatment Planning Systems (TPSs) generally approximate the dose profiles by a sum of Gaussian functions. In this paper we have compared different parametrizations for the lateral dose profile of protons in water for therapeutical energies: the goal is to improve the performances of the actual treatment planning. METHODS: We have simulated typical dose profiles at the CNAO (Centro Nazionale di Adroterapia Oncologica) beamline with the FLUKA code and validated them with data taken at CNAO considering different energies and depths. We then performed best fits of the lateral dose profiles for different functions using ROOT and MINUIT. RESULTS: The accuracy of the best fits was analyzed by evaluating the reduced χ(2), the number of free parameters of the functions and the calculation time. The best results were obtained with the triple Gaussian and double Gaussian Lorentz-Cauchy functions which have 6 parameters, but good results were also obtained with the so called Gauss-Rutherford function which has only 4 parameters. CONCLUSIONS: The comparison of the studied functions with accurate and validated Monte Carlo calculations and with experimental data from CNAO lead us to propose an original parametrization, the Gauss-Rutherford function, to describe the lateral dose profiles of proton beams.
Authors: Liyong Lin; Sheng Huang; Minglei Kang; Petri Hiltunen; Reynald Vanderstraeten; Jari Lindberg; Sami Siljamaki; Todd Wareing; Ian Davis; Allen Barnett; John McGhee; Charles B Simone; Timothy D Solberg; James E McDonough; Christopher Ainsley Journal: J Appl Clin Med Phys Date: 2017-02-02 Impact factor: 2.102
Authors: James E Younkin; Danairis Hernandez Morales; Jiajian Shen; Jie Shan; Martin Bues; Jarrod M Lentz; Steven E Schild; Joshua B Stoker; Xiaoning Ding; Wei Liu Journal: Technol Cancer Res Treat Date: 2019 Jan-Dec