Download Citation on ResearchGate | On Jan 1, , D. W.O. Rogers and others published BEAMnrc users manual }. BEAMnrc: software tool to model radiation beams. BEAMnrc is now part of EGSnrc. Report a problem or mistake on this page. Please select all. BEAMnrc, DOSXYZnrc and BEAMDP GUI users manual.
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This efficiency gain is achieved through the use of variance reduction techniques and faster simulation of the beamndc transport. National Center for Biotechnology InformationU. For both field sizes, the results are presented in Gy per incident particle.
The CPU times were scaled to a single 2. It has been reported that this option increases the efficiency of homogeneous phantom calculations, 38 however, no photon splitting or charged particle range rejection were employed. On the other hand, the scattered photon can be mmanual to interact again in the forcing zone, depending on how many forced interactions are still available.
The following efficiency enhancing methods were considered: In bdamnrc, the methods for performing the efficiency and statistical uncertainty calculations are described.
A systematic study of the influence of efficiency enhancing methods available in BEAMnrc on the accuracy of calculated fluence and dose distributions. Augmented charged particle range rejection is only available when used simultaneously with DBS. The current version of BEAMnrc allows the user to choose three photon cross sections: The electron and photon cutoff energies were set to 0.
Therefore, if one is concerned with the smallest statistical uncertainty variance in dose, then it is best to perform the treatment head PS simulation without VRTs.
VRTs do not change the physics and therefore do not bias the results. Springer, Berlin,pp. Efficiencies are shown relative to the efficiency obtained for the BEAMnrc default case. Russian Roulette was also considered with the photon splitting techniques.
BEAMnrc: software tool to model radiation beams
Open in a separate window. For a particular efficiency enhancing technique used in BEAMnrcthe difference between the relative efficiencies obtained geamnrc the various estimates of the uncertainty increases as one changes from planar fluence to spectral distribution; this situation is clearly more evident for the larger field size see Figs.
Springer-Verlag, Heidelberg,pp. CPU time is scaled to that of a single 2.
BEAMnrc, DOSXYZnrc and BEAMDP GUI users manual – NRC Publications Archive –
This occurs because of particle correlations which are introduced with the use of VRTs, such as bremsstrahlung splitting. Here, we investigate the efficiency enhancing methods and cross-section data available in the BEAMnrc MC code system and their effect on the accuracy of calculated fluence and dose distributions. In addition, the relative efficiencies are dependent on the manuaal of interest chosen, although one can claim from this study that BEAMnrc MC calculations with the directional bremsstrahlung splitting technique yields the highest efficiency for all quantities of interest analyzed.
The percentage difference, in the central region of the field and at different depths, between the two MC calculated data is also shown.
The percentage difference between measured and a selection of MC calculated central-axis dose profiles is also shown. The mean energy and planar fluence were extracted from the PHSP in circular ring bins of equal area, the spectral distribution in energy bins of equal bin width, and the angular distribution in angular bins of equal bin width.
A photon forced to interact is split into a scattered photon whose weight is equal to the probability of interaction and an unscattered photon carrying the remaining weight. If one uses VRTs e. The mean energy, planar fluence, and angular and spectral distributions were used as quantities of interest and the estimate of the uncertainty was calculated in five different ways, i. Data Tables 7 6— With SBS, the value of NBRSPL is changed in order to maximize the splitting of photons aimed into the field and to minimize unnecessary mahual of photons aimed away from the field.
Monte Carlo transport parameters Maximum electron step, smax cm 10 Maximum mxnual loss per step MeV 0. The photon forcing parameters can also be passed onto secondary photons and this feature is particularly useful to improve calculation efficiency for bremsstrahlung photon interactions, especially when combined with bremsstrahlung photon splitting. In our study, ESAVE was set to 2 MeV in all component modules with the exception of the target where the electron cutoff energy value was used, as recommended in Sheikh—Bagheri et al.
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