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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Data Tables 7 6— This is essential if one mannual considering real-time MC simulation of the treatment head and patient. The initial number of histories was set to obtain approximately the same number of particles in the PHSP files, i.
The current version of BEAMnrc allows the user to choose three photon cross sections: Academic, New York,Vol.
The percentage difference, in the central region of the field and at different depths, between measured and a selection of MC calculated off-axis dose profiles is also shown.
PIRS E This work was supported in part by Grant Nos. Photon interaction forcing With photon interaction forcing, the user can force photons to interact up to a user-defined number of times, Nin specified component modules within a simulation. On the other hand, if one is interested in the most efficient PS simulation note that efficiency is the inverse product msnual variance and timethen it is necessary to use VRTs.
BEAMnrc, DOSXYZnrc and BEAMDP GUI users manual – NRC Publications Archive –
Although significant differences in the mean energy, planar fluence, and angular and spectral distributions were observed when comparing the NIST and BH bremsstrahlung cross-section PHSP files, they were not reflected in the calculated dose distribution in a water phantom with and without an air gap.
The CPU times were scaled to a single 2. An investigation of the influence of different photon and bremsstrahlung cross-section data available in BEAMnrc on the accuracy of calculated fluence and dose distributions. Augmented range rejection accounts correctly for bremsstrahlung manuwl, since charged particles surviving Russian Roulette and with their weight increased by a factor of NBRSPL still have a chance to undergo bremsstrahlung events. Some of these special-purpose MC codes are being used as a dose engine for MC-based treatment planning in the routine clinical setting.
BEAMnrc: software tool to model radiation beams
When changing the bremsstrahlung differential cross section from BH to NIST, the default photon beambrc section was used, i. The percentage difference between measured and a selection of MC calculated central-axis dose profiles is also shown. Springer-Verlag, Heidelberg,pp. Efficiencies are shown relative to the efficiency obtained for the BEAMnrc default case.
BEAMnrc: software tool to model radiation beams – National Research Council Canada
Monte Carlo transport parameters Maximum electron step, smax cm 10 Maximum electron loss per step MeV 0. The percentage difference between the two MC calculated data is also shown. Once it leaves the forcing zone, the unscattered photon may interact again, depending on the sampled path length.
The use of sophisticated variance reduction and approximate efficiency improving techniques, combined with parallel processing in computer clusters and the continuing increase in computing power, will help make MC-based treatment planning a mainstay option in radiation oncology departments. VRTs do not change the physics and therefore do not bias the results. Photon and bremsstrahlung cross sections The current version of BEAMnrc allows the user to choose three different photon cross sections: 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.
The percentage difference between the two MC calculations is also shown. Boundary crossing algorithm The boundary crossing algorithm together with the electron transport algorithm constitutes the condensed history technique used by a particular MC code system.
The boundary crossing algorithm together with the electron transport algorithm constitutes the condensed history technique used by a particular MC code system. This efficiency gain is achieved through the use of variance reduction techniques and faster simulation of the electron transport.
If one uses VRTs e. The following efficiency enhancing methods were considered: Estimates of the uncertainty using a significant number of bins e. This occurs because of beamnc correlations which are introduced with the use of VRTs, such as bremsstrahlung splitting. Published online Nov 5. Another important consideration is that the relative fluence efficiency, for a given splitting number, actually decreases with increase scoring zone area, a result derived mathematically in an article by Kawrakow.
There is another viewpoint concerning PHSP simulations of the linac treatment head, which should be considered.
When using UBS, each bremsstrahlung event produces a predefined number of bremsstrahlung photons, each having a weight equal to the inverse of the splitting number NBRSPL times the weight of the electron that underwent the bremsstrahlung event. On the other hand, the scattered manuall can be forced to interact again in the forcing zone, depending on how many forced interactions are still available.
The uncertainty was calculated in five different ways, i. Augmented charged particle range rejection is only available when used simultaneously with DBS. The default differential cross section for the bremsstrahlung interactions is Bethe—Heitler BH. Monte Carlo, efficiency, variance reduction techniques, cross sections.
The mean energy and planar fluence were extracted from the PHSP in circular ring bins of equal area, the spectral distribution in beanrc bins of equal bin width, and the angular distribution in angular bins of equal bin width.
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