### Abstract

Based on the Fermiâ€“Eyges theory, a set of recursion relations was derived for calculating electron distributions in the layered geometry. The electron distribution at a specific depth was obtained by convolving the upstream electron distribution with a kernel determined by the scattering parameters of the layer. Modifications were made to overcome some inherent limitations of the Fermiâ€“Eyges theory. For each point in the medium, the most probable, or mean, path traversed by the electrons in reaching the point was derived. The skewness of the mean paths and the related energy degradation were included in a multiray model for pencil beam calculations. The resultant electron planar fluence distributions are no longer Gaussian as predicted by the original theory. The effects of edges or localized inhomogeneities are also included. Comparisons between our calculations and Monte Carlo simulations show good agreement.

Original language | English (US) |
---|---|

Pages (from-to) | 662-671 |

Number of pages | 10 |

Journal | Medical Physics |

Volume | 15 |

Issue number | 5 |

DOIs | |

State | Published - 1988 |

Externally published | Yes |

### Fingerprint

### Keywords

- ALGORITHMS
- ELECTRON BEAMS
- ELECTRON DOSIMETRY
- INHOMOGENEITY
- RADIATION DOSE DISTRIBUTIONS
- RADIOTHERAPY

### ASJC Scopus subject areas

- Biophysics
- Radiology Nuclear Medicine and imaging

### Cite this

*Medical Physics*,

*15*(5), 662-671. https://doi.org/10.1118/1.596180

**A multiray model for calculating electron pencil beam distribution.** / Yu, C. X.; Ge, W. S.; Wong, John.

Research output: Contribution to journal › Article

*Medical Physics*, vol. 15, no. 5, pp. 662-671. https://doi.org/10.1118/1.596180

}

TY - JOUR

T1 - A multiray model for calculating electron pencil beam distribution

AU - Yu, C. X.

AU - Ge, W. S.

AU - Wong, John

PY - 1988

Y1 - 1988

N2 - Based on the Fermiâ€“Eyges theory, a set of recursion relations was derived for calculating electron distributions in the layered geometry. The electron distribution at a specific depth was obtained by convolving the upstream electron distribution with a kernel determined by the scattering parameters of the layer. Modifications were made to overcome some inherent limitations of the Fermiâ€“Eyges theory. For each point in the medium, the most probable, or mean, path traversed by the electrons in reaching the point was derived. The skewness of the mean paths and the related energy degradation were included in a multiray model for pencil beam calculations. The resultant electron planar fluence distributions are no longer Gaussian as predicted by the original theory. The effects of edges or localized inhomogeneities are also included. Comparisons between our calculations and Monte Carlo simulations show good agreement.

AB - Based on the Fermiâ€“Eyges theory, a set of recursion relations was derived for calculating electron distributions in the layered geometry. The electron distribution at a specific depth was obtained by convolving the upstream electron distribution with a kernel determined by the scattering parameters of the layer. Modifications were made to overcome some inherent limitations of the Fermiâ€“Eyges theory. For each point in the medium, the most probable, or mean, path traversed by the electrons in reaching the point was derived. The skewness of the mean paths and the related energy degradation were included in a multiray model for pencil beam calculations. The resultant electron planar fluence distributions are no longer Gaussian as predicted by the original theory. The effects of edges or localized inhomogeneities are also included. Comparisons between our calculations and Monte Carlo simulations show good agreement.

KW - ALGORITHMS

KW - ELECTRON BEAMS

KW - ELECTRON DOSIMETRY

KW - INHOMOGENEITY

KW - RADIATION DOSE DISTRIBUTIONS

KW - RADIOTHERAPY

UR - http://www.scopus.com/inward/record.url?scp=0023815330&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023815330&partnerID=8YFLogxK

U2 - 10.1118/1.596180

DO - 10.1118/1.596180

M3 - Article

VL - 15

SP - 662

EP - 671

JO - Medical Physics

JF - Medical Physics

SN - 0094-2405

IS - 5

ER -