Welcome to the PRIMO project website.

PRIMO is a computer software that simulates clinical linear accelerators (linacs) and estimates absorbed dose distributions in phantoms and computerized tomographies. It combines a graphical user interface with the general-purpose radiation transport Monte Carlo code PENELOPE and the fast Monte Carlo code DPM (see publications).

These are its most relevant features:

  • It simulates most Varian [1] and Elekta [2] linacs, with their electron applicators and multileaf collimators. Varian TrueBeam STx machines can also be simulated using the phase-space files distributed by the vendor, or alternatively, with an experimentally-based complete geometry called FakeBeam. Elekta linacs are only supported in version 0.1.5.
  • Absorbed dose distributions can be obtained in a phantom or in computerized tomographies provided in DICOM [3] format.
  • Structures can be delineated (version 0.1.5) or, alternatively, they can be imported in DICOM-RT STRUCT [3] format.
  • Treatment plans can be imported in DICOM-RT PLAN [3] format (version 0.3.1).
  • Radiation fields can be stored in intermediate phase-space files that comply with the IAEA [4] format. Graphical and numerical analysis tools for phase-space files are provided.
  • Absorbed dose distributions can be computed from dynalog files and compared to the original plan as well as the plan computed with PENELOPE or pDPM in PRIMO (version 0.3.1).
  • A macro mode for automatized operation of PRIMO is available (version 0.3.1).
  • A graphical interface guides users through the simulation and analysis of results with just a few clicks. Basic know-how common to all medical radiation physicists is assumed, but no previous knowledge about the Monte Carlo method or linac inner workings is required.

PRIMO is free software. But it is not open source. Please read the Disclaimer and Copyright statements under the download page for further details.

If you are willing to provide feedback, report bugs, give suggestions or ask questions, please send us an email using the contact information in the about the authors section.

Thank you for using PRIMO.



[1] Varian Medical Systems Inc, California, USA

[2] Elekta AB, Sweden

[3] Digital Imaging and Communications in Medicine. See http://dicom.nema.org

[4] R. Capote et al., Phase-Space Database for External Beam Radiotherapy. Report INDC (NDS)-0484, International Nuclear Data Committee, International Atomic Energy Agency 2006, Vienna, Austria. See http://www-nds.iaea.org

Last edited: 2021-10-08