PENELOPE/PRIMO-calculated photon and electron spectra from clinical accelerators

Abstract

BackgroundThe availability of photon and electron spectra in digital form from current accelerators and Monte Carlo (MC) systems is scarce, and one of the packages widely used refers to linacs with a reduced clinical use nowadays. Such spectra are mainly intended for the MC calculation of detector-related quantities in conventional broad beams, where the use of detailed phase-space files (PSFs) is less critical than for MC-based treatment planning applications, but unlike PSFs, spectra can easily be transferred to other computer systems and users.MethodsA set of spectra for a range of Varian linacs has been calculated using the PENELOPE/PRIMO MC system. They have been extracted from PSFs tallied for field sizes of 10 cm × 10 cm and 15 cm × 15 cm for photon and electron beams, respectively. The influence of the spectral bin width and of the beam central axis region used to extract the spectra have been analyzed.ResultsSpectra have been compared to those by other authors showing good agreement with those obtained using the, now superseded, EGS4/BEAM MC code, but significant differences with the most widely used photon data set. Other spectra, particularly for electron beams, have not been published previously for the machines simulated in this work. The influence of the bin width on the spectrum mean energy for 6 and 10 MV beams has been found to be negligible. The size of the region used to extract the spectra yields differences of up to 40% for the mean energies in 10 MV beams, but the maximum difference for TPR 20,10 values derived from depth-dose distributions does not exceed 2% relative to those obtained using the PSFs. This corresponds to kQ differences below 0.2% for a typical Farmer-type chamber, considered to be negligible for reference dosimetry. Different configurations for using electron spectra have been compared for 6 MeV beams, concluding that the geometry used for tallying the PSFs used to extract the spectra must be accounted for in subsequent calculations using the spectra as a source.ConclusionsAn up-to-date set of consistent spectra for Varian accelerators suitable for the calculation of detector-related quantities in conventional broad beams has been developed and made available in digital form.Electronic supplementary materialThe online version of this article (10.1186/s13014-018-1186-8) contains supplementary material, which is available to authorized users.

Monte carlo calculation of the energy spectrum of a 6 MeV electron beam using penetration and energy loss of positrons and electrons code

“…It has extensive information on various applications for radiotherapy and radiodiagnosis. [ 4 29 30 31 32 33 34 ] Since its first version launched in 1996, the MCS PENELOPE code has become a flexible and reliable tool to describe the coupled transport of photons and electrons in complex material structures,[ 35 36 ] presenting simplicity and versatility to be used in the two most used programming platforms such as Windows and Linux without the necessity of the usage of an intermediary interface. Moreover, the results obtained are presented in .dat extension which is easy to read in any code for statistical analysis such as Origin, Matlab, and Gnuplot.…”

“…The main motivation of this work is related to there are few research papers about the use of MCS to determine energy spectra of electron beams[ 21 31 37 38 ] and its characteristic dosimetric parameters in comparison to those existent for photon beam,[ 11 31 33 39 40 41 42 43 44 45 46 ] especially for linear accelerators still used in developing countries. Thus, in this work, an Elekta Synergy Platform linear accelerator was used as a reference, since the Synergy is still one of the most used accelerators in the Latin-American market and other developing regions of the world.…”

Generative adversarial networks (GAN) for compact beam source modelling in Monte Carlo simulations

“…Chabert et al [4] used 4D correlated histograms with different adaptive binning schemes to represent an Elekta Synergy 6 MV photon beam. Recently, Brualla et al [5] proposed a method to extract light-weight spectra from large phase space files. This method may be sufficient for some applications, but may neglect correlations between energy, position and direction and require adaptive binning.…”

Investigation of variance reduction techniques parameters to enhance the efficiency for a 12 MV photon beam

“…In the last years, there have been rapid developments in computer technology that lead to exponential increase in processor speed, as well as improvements in software optimization and networking technology and have made MC technique treatment planning a feasible choice (Caccia et al, 2007;Foley, Conneely, Alexander, Stroian, & Seuntjens, 2013). A number of MC codes are now in clinical use, such as BEAMnrc, VMC++ (Hasenbalg, Fix, Born, Mini, & Kawrakow, 2008), PENELOPE (Brualla, Rodriguez, Sempau, & Andreo, 2019;Sempau, Badal, & Brualla, 2011), GEANT4 (EL Bakkali et al, 2016), MCNPX (Zoubair et al, 2013).…”