A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.
To introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation.A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a S...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2017-01-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC5590861?pdf=render |
| _version_ | 1818453471407374336 |
|---|---|
| author | Obioma Nwankwo Gerhard Glatting Frederik Wenz Jens Fleckenstein |
| author_facet | Obioma Nwankwo Gerhard Glatting Frederik Wenz Jens Fleckenstein |
| author_sort | Obioma Nwankwo |
| collection | DOAJ |
| description | To introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation.A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs) for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC) between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses.The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate) for the evaluated fields.A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm. |
| first_indexed | 2024-12-14T21:39:31Z |
| format | Article |
| id | doaj.art-4185e0a3ee3340858eae272aa3ea2573 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-14T21:39:31Z |
| publishDate | 2017-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-4185e0a3ee3340858eae272aa3ea25732022-12-21T22:46:30ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01129e018348610.1371/journal.pone.0183486A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.Obioma NwankwoGerhard GlattingFrederik WenzJens FleckensteinTo introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation.A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs) for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC) between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses.The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate) for the evaluated fields.A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.http://europepmc.org/articles/PMC5590861?pdf=render |
| spellingShingle | Obioma Nwankwo Gerhard Glatting Frederik Wenz Jens Fleckenstein A single-source photon source model of a linear accelerator for Monte Carlo dose calculation. PLoS ONE |
| title | A single-source photon source model of a linear accelerator for Monte Carlo dose calculation. |
| title_full | A single-source photon source model of a linear accelerator for Monte Carlo dose calculation. |
| title_fullStr | A single-source photon source model of a linear accelerator for Monte Carlo dose calculation. |
| title_full_unstemmed | A single-source photon source model of a linear accelerator for Monte Carlo dose calculation. |
| title_short | A single-source photon source model of a linear accelerator for Monte Carlo dose calculation. |
| title_sort | single source photon source model of a linear accelerator for monte carlo dose calculation |
| url | http://europepmc.org/articles/PMC5590861?pdf=render |
| work_keys_str_mv | AT obiomanwankwo asinglesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation AT gerhardglatting asinglesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation AT frederikwenz asinglesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation AT jensfleckenstein asinglesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation AT obiomanwankwo singlesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation AT gerhardglatting singlesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation AT frederikwenz singlesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation AT jensfleckenstein singlesourcephotonsourcemodelofalinearacceleratorformontecarlodosecalculation |