EGSnrc: software tool to model radiation transport

Overview of the software

NRC’s electron gamma shower (EGS) software tool can meet your specific requirements relating to modelling the passage of electrons and photons through matter. EGSnrc relies on Monte Carlo, which is the most accurate method to model the transport of radiation.

EGSnrc is used to address a broad range of questions about the propagation of radiation in materials. It is particularly well-suited for medical physics purposes, such as the research and development of devices that allow medical professionals to detect radiation, image a patient’s anatomy using x-rays, or deliver a prescribed radiation dose to a tumour while sparing healthy tissue. The software is also employed directly by medical physicists in cancer clinics for research and for verifying radiation treatment plans.

NRC also trains Canadian and international physicists on use of the software.

NRC contributes to the development and application of the Monte Carlo method in the modelling of radiation transport since the early 1980s. The EGSnrc software is now downloaded more than 3,000 times per year by academic, medical and industrial researchers worldwide.

Targeted audience

  • Medical physicists, universities and hospitals.
  • Companies that develop radiotherapy equipment and software.
  • Universities and industries working with radiation, including radiation measurement, radiotherapy, radiation protection, radiation processing, medical imaging, and other electron and photon radiation applications.

Description of the software

The EGSnrc code system is a general-purpose software toolkit that can be applied to build Monte Carlo simulations of coupled electron-photon transport, for particle energies ranging from 1 keV to 10 GeV.

EGSnrc is an extended and improved version of the EGS4 code system developed jointly by NRC and the Stanford Linear Accelerator Center in the 1980s (WR Nelson, H Hirayama, DWO Rogers. The EGS4 code system, Report SLAC-265, 1985). The EGSnrc implementation improves the accuracy and precision of the charged particle transport mechanics and the atomic scattering cross-section data (I Kawrakow. Accurate condensed history Monte Carlo simulation of electron transport. I. EGSnrc, the new EGS4 version. Medical physics 27, 2000). It also comprises a C++ geometry library for defining the geometry of complex simulation environments and particle sources.

System requirements

EGSnrc works on GNU/Linux, Unix, Mac OS X and Windows. EGSnrc is a set of source files and utilities to build your own Monte Carlo simulations. As such, it is not a stand-alone software and requires the following:

  • Fortran, C and C++ compilers
  • The GNU make utility
  • The Tcl/Tk interpreter and GUI toolkit
  • Grace (to display results graphically)


EGSnrc is trusted by researchers worldwide for simulation accuracy and speed. It is widely regarded as the most accurate computer program for electron and photon transport simulation. The EGS code has been used extensively by medical physicists over the past four decades, resulting in thousands of publications in scientific journals. Through this rigorous peer-review process it has evolved into a reliable and well-benchmarked software. EGSnrc continues to be referenced in around 30 per cent of all Monte Carlo related publications in the leading journals Medical Physics and Physics in Medicine and Biology. Commercial partners around the world also rely upon EGSnrc for the design of radiation equipment and software, as is evidenced by commercial license agreements that are already in place.


The software is freely available for research and other non-commercial purposes. Please read the full license agreements before downloading. Companies wishing to use the software should contact NRC to obtain a commercial licence.


For technical inquiries

Dr. Frédéric Tessier
Telephone: 613-993-9352 ext. 237

Dr. Ernesto Mainegra-Hing
Telephone: 613-993-9352 ext. 260

For business inquiries