VMC++ versus BEAMnrc: a comparison of simulated linear accelerator heads for photon beams

Hasenbalg, F; Fix, M K; Born, E J; Mini, R; Kawrakow, I (2008). VMC++ versus BEAMnrc: a comparison of simulated linear accelerator heads for photon beams. Medical physics, 35(4), pp. 1521-31. College Park, Md.: American Association of Physicists in Medicine AAPM 10.1118/1.2885372

Full text not available from this repository. (Request a copy)

BEAMnrc, a code for simulating medical linear accelerators based on EGSnrc, has been bench-marked and used extensively in the scientific literature and is therefore often considered to be the gold standard for Monte Carlo simulations for radiotherapy applications. However, its long computation times make it too slow for the clinical routine and often even for research purposes without a large investment in computing resources. VMC++ is a much faster code thanks to the intensive use of variance reduction techniques and a much faster implementation of the condensed history technique for charged particle transport. A research version of this code is also capable of simulating the full head of linear accelerators operated in photon mode (excluding multileaf collimators, hard and dynamic wedges). In this work, a validation of the full head simulation at 6 and 18 MV is performed, simulating with VMC++ and BEAMnrc the addition of one head component at a time and comparing the resulting phase space files. For the comparison, photon and electron fluence, photon energy fluence, mean energy, and photon spectra are considered. The largest absolute differences are found in the energy fluences. For all the simulations of the different head components, a very good agreement (differences in energy fluences between VMC++ and BEAMnrc <1%) is obtained. Only a particular case at 6 MV shows a somewhat larger energy fluence difference of 1.4%. Dosimetrically, these phase space differences imply an agreement between both codes at the <1% level, making VMC++ head module suitable for full head simulations with considerable gain in efficiency and without loss of accuracy.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Radiation Oncology > Medical Radiation Physics

UniBE Contributor:

Hasenbalg, Federico; Fix, Michael; Born, Ernst Johann and Mini, Roberto






American Association of Physicists in Medicine AAPM




Factscience Import

Date Deposited:

04 Oct 2013 15:03

Last Modified:

04 May 2014 23:19

Publisher DOI:


PubMed ID:


Web of Science ID:



https://boris.unibe.ch/id/eprint/27371 (FactScience: 106832)

Actions (login required)

Edit item Edit item
Provide Feedback