The Vin č a Institute of Nuclear Sciences, Belgrade, Serbia * Universita degli studi di Bologna, DIENCA, Italia Radovan D. Ili}, Milan Pe{i}, Radojko Pavlovi} and * Domiziano Mostacci INTERCOMPARISON OF THE USAGE OF COMPUTATIONAL CODES IN RADIATION DOSIMETRY Bologna, Italy, July P3. Dose distribution of a proton beam in water phantom calculated by code SRNA-2KG

A parallel beam of protons from a disk source (diameter 15 mm) impinges on a PMMA compensator (cylindrical symmetry) and on a spherical water phantom approximating an eye (figure 1). All elements are in vacuum. If discrete regions are used for dose calculations (depth-dose and isodose curves), use voxels with dimensions 0.5 x 0.5 x 0.5 mm3. The results should be normalized to one primary proton

NUMERICAL EXPERIMENTS BY SRNA-2KG CODE The SRNA-2KG is a Monte Carlo code for use in proton transport, radiotherapy, and dosimetry. Protons within an energy range of 100 keV to 250 MeV with pre-specified spectra are transported in a 3D geometry through material zones confined by planes and second order surfaces or in 3D voxelized geometry. The simulation of proton transport is based on the multiple scattering theory of charged particles and on a model for compound nucleus decay. For each part of the range, an average loss of energy is calculated with a fluctuation from Vavilovs distribution. The deflection angle of protons is sampled from Moliere distribution.

SRNA-2KG code attributes: Physical model is theoretically consistent for 3D Monte Carlo numerical experiments Comprehensive for dosimetry and proton therapy Works in 3D combined and 3D voxelized medium and source geometries Linux or Windows Fortran 77 source code and libraries on one floppy 3.5” [Ref] R. D. Ili}, D. Lalic and S. J. Stankovi} SRNA - Monte Carlo codes for proton transport simulation in combined and voxelized geometries, accepted to Nucl. Techn. and Rad. Protect., No 1-2 (2002).

Part 1/1: 50 MeV monoenergetic proton beam Depth-dose distribution in spherical phantom along the diameter D parallel to the proton beam

Part 1/2a: 50 MeV monoenergetic proton beam Isodose curves on the equatorial plane of the water phantom parallel to the proton beam

Part 2/1: Effect of a beam modulator obtained by sampling discrete energies lines from (40-50) MeV spectrum Depth-dose distribution in spherical phantom along the diameter D parallel to the proton beam

Part 2/2a: Effect of a beam modulator obtained by sampling discrete energies lines from (40-50) MeV Isodose curves on the quatorial plane of the water phantom parallel to the proton beam

Part 2/1: Effect of a beam modulator obtained by sampling energies from (40-50) MeV histogram distribution Depth-dose distribution in spherical phantom along the diameter D parallel to the proton beam

Part 2/2a: Effect of a beam modulator obtained by sampling energies from (40-50) MeV histogram distribution. Isodose curves on the equatorial plane of the water phantom parallel to the proton beam.