Monte Carlo simulations
Monte Carlo simulations are used to calculate energy deposition in reference human models as a function of particles type, energy and location. Particles can be located in any region of the model (source), where they are emitted isotropically. Monte Carlo simulations are performed for monoenergetic photons and electrons from 5 keV to 10 MeV (log scale). Energy deposits are recorded in every voxel and every region of the model (target), along with their estimated statistical uncertainties. Energy deposits are then converted in Specific Absorbed Fractions (SAFs), which are used to calculate S values.
Producing a complete data set for one model (all sources, particle types and energies) requires ∼30 000 simulations, the equivalent of ∼750,000 CPU hours of computation. Monte Carlo simulations being "embarrassingly parallel", and thanks to the multiple computing resources of the OpenDose collaboration, the data for one model can be produced in a few months.
Production status
The data production status can be observed with the button below. It makes a query on the whole OpenDose database and displays how many simulations have been made for each model. By hovering the charts, the label shows the count (number of simulations) for a source - target couple.
The Monte Carlo codes
The OpenDose collaboration produces dosimetric data using a variety of Monte Carlo codes. This ensure that data is produced independently between different teams and doesn't rely on a single physics model or particle tracking system. A script written in Python automatically scans the data to detect large discrepancies between codes.
Here is a short description of the Monte Carlo codes currently used within the collaboration:
EGS [1] (Electron Gamma Shower) is a computer code system is a general purpose package for the
Monte Carlo simulation of the coupled transport of electrons and photons in an arbitrary geometry
for particles with energies from a few keV up to several hundreds of GeV. It originated at
SLAC but National Research Council of Canada and KEK have been involved in its development since
the early 80s.
https://nrc.canada.ca/research-development/egsnrc
http://rcwww.kek.jp/research/egs
FLUKA [2] (FLUktuierende KAskade) is a closed-source fully integrated Monte Carlo simulation
package for the interaction and transport of particles and nuclei in matter. FLUKA has many
applications in particle physics, high energy experimental physics and engineering, shielding,
detector and telescope design, cosmic ray studies, dosimetry, medical physics and radiobiology.
http://www.fluka.org
GATE [3] (Geant4 Application for Tomographic Emission) is an advanced Geant4 application
dedicated to numerical simulations in medical imaging and radiotherapy. Its development,
maintenance and user support are taken care by the international OpenGATE collaboration.
It currently supports simulations of Emission Tomography (Positron Emission Tomography -
PET and Single Photon Emission Computed Tomography - SPECT), Computed Tomography (CT),
Optical Imaging (Bioluminescence and Fluorescence), dosimetry and Radiotherapy experiments.
http://www.opengatecollaboration.org
Geant4 [4] (GEometry ANd Tracking) is a platform for "the simulation of the passage of
particles through matter" using Monte Carlo methods. It is the successor of the GEANT series of
software toolkits developed by CERN, and the first to use object oriented programming (in C++).
Its development, maintenance and user support are taken care by the international Geant4
Collaboration. Application areas include high energy physics and nuclear experiments, medical,
accelerator and space physics studies.
http://www.geant4.org
MCNP [5] (Monte Carlo N-Particle) is a software package for simulating nuclear processes.
It is developed by Los Alamos National Laboratory since 1957.
It is used primarily for the simulation of nuclear processes, such as fission, but has the
capability to simulate particle interactions involving neutrons, photons, and electrons among
other particles. MCNP application areas include radiation protection and dosimetry, radiation
shielding, radiography, medical physics, nuclear criticality safety, detector design and
analysis, nuclear oil well logging, accelerator target design, fission and fusion reactor
design, decontamination and decommissioning.
https://mcnp.lanl.gov
PENELOPE
PENELOPE [6] (Penetration and ENErgy LOss of Positrons and Electrons) is a general-purpose
Monte Carlo simulation code system.
It is distributed by the Nuclear Energy Agency since 2001.
It simulates coupled electron-photon transport in arbitrary materials for a wide energy range,
from a few hundred eV to 1 GeV. PENELOPE applications include radiotherapy, nuclear medicine,
dosimetry, radiation metrology, electron microscopy (SEM, electron-probe microanalysis),
detector response and x-ray generators.
https://www.oecd-nea.org/tools/penelope
[1] Kawrakow I, Mainegra-Hing E, Rogers DWO, Tessier F, Walters BRB. The EGSnrc Code System: Monte Carlo simulation of electron and photon transport. Technical Report PIRS-701, National Research Council Canada, 2017.
[2] Böhlen T et al. The FLUKA code: Developments and challenges for high energy and medical applications. Nuclear Data Sheets, vol. 120, pp. 211–214, 2014.
[3] Sarrut D et al. A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications. Medical Physics, vol. 41, no. 6Part1, p. 064301, 2014.
[4] Agostinelli S et al. Geant4—a simulation toolkit. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 506, no. 3, pp. 250–303, 2003.
[5] Waters LS et al. The MCNPX Monte Carlo radiation transport code. AIP Conference Proceedings, vol. 896, no. 1, pp. 81–90, 2007.
[6] Salvat F, Fernandez-Varea JM, Sempau J. PENELOPE-2011: A code system for Monte Carlo simulation of electron and photon transport. OECD Nuclear Energy Agency, Issy-les-Moulineaux, 2014.