Loading...
Please wait, while we are loading the content...
Similar Documents
A theoretical multileaf collimator model for fast Monte Carlo dose calculation of linac 6/10 MV photon beams
| Content Provider | Scilit |
|---|---|
| Author | Aboulbanine, Zakaria Khayati, Naïma El |
| Copyright Year | 2019 |
| Description | Journal: Biomedical Physics & Engineering Express A complete linac photon beam Monte Carlo dose calculation, even on a fast computer, requires generally a substantial computation time. The existing approaches developed to improve the efficiency are mainly based on the use of variance reduction techniques, phase space sources or virtual source models. The collimation of the simulated photon beam, involving particle transport through the multileaf collimator, considerably increases the calculation time especially for intensity modulation radiation therapy, where multiple small and medium field shapes are taking place. In this paper improvements of a previous model will aim to significantly enhance the calculation efficiency for fast intensity modulation computations mainly by the use of an analytical collimator. The model uses only correlated energy spectra and particle fluence distributions derived from the International Atomic Energy Agency phase space files of Elekta Precise 6 MV/10 MV and Varian TrueBeam 6 MV photon beams. The scattered electrons and positrons contained in the phase space files were not considered; only the photon component is modelled. The effect of the collimation on the particle fluence is emulated by a developed analytical "Collimator Filter Function", describing the transmission of each pair of leaves. The obtained fluence is then used for particle sampling. Extensive dose calculations were performed in a water phantom of 2 $mm^{3}$ voxel size; dose calculations were carried out using the multi-threaded Geant4-[mt] Monte Carlo package. Multiple regular squared fields of different sizes from 30×30 $cm^{2}$ to the 3×3 $cm^{2}$, an asymmetric rectangular field 20×7 $cm^{2}$ and an intensity modulation sample field consisting of seven segments were considered for the validation. A 3D $γ_{index}$ analysis has shown a good agreement in terms of the 2%/2 mm and 3%/3 mm criteria for all radiation fields. The speedup factor for the intensity modulation field reached ×43 compared to the classical phase space calculation. |
| Related Links | https://iopscience.iop.org/article/10.1088/2057-1976/ab3510/pdf |
| ISSN | 20571976 |
| e-ISSN | 20571976 |
| DOI | 10.1088/2057-1976/ab3510 |
| Journal | Biomedical Physics & Engineering Express |
| Issue Number | 5 |
| Volume Number | 5 |
| Language | English |
| Publisher | IOP Publishing |
| Publisher Date | 2019-07-25 |
| Access Restriction | Open |
| Subject Keyword | Journal: Biomedical Physics & Engineering Express Nuclear Energy and Engineering Multileaf Collimator Photon Beam |
| Content Type | Text |
| Resource Type | Article |
| Subject | Physiology Radiology, Nuclear Medicine and Imaging Biomaterials Biophysics Bioengineering Biomedical Engineering Health Informatics Computer Science Applications |
