### Abstract

Monte Carlo N-Particle 6 (MCNP6) is the latest version of Los Alamos National Laboratory's powerful Monte Carlo software designed to compute general photon, neutron, and electron transport using stochastic algorithms. Here we provide a case study of modeling the photon beam of a Varian 600C Clinical Linear Accelerator (linac), which is used to deliver radiation therapy, along with a comparison to experimentally measured beam characteristics. The source definition parameters in MCNP6, including the energy spectrum and angular spectrum of the photons, secondary and tertiary collimators, and a water phantom that tallied dose delivered at different points along the phantom are included. The experimental data for comparison was in the form of a percent depth dose curve as well as crossline and inline beam profiles. Experimental depth dose curve and beam profiles were acquired using a standard 0.125 cc ion chamber within a water phantom. In the computational model, the simulated depth dose curve was computed by tallying the total energy deposited in a stack of vertical slices down the depth of the phantom for percent depth dose curves. The simulated beam profiles were computed in a similar fashion, by tallying the energy deposited in a horizontal row, both in the x- and y-directions of cubic cells located at various depths. For the percent depth dose curve, a mean absolute percentage difference of 1.02%, 1.07%, and 1.94% were calculated for field sizes of 5 × 5 cm^{2}, 10 × 10 cm^{2} and 20 × 20 cm^{2}, respectively, between the model and experimental measurements were calculated. We present our model as an example to guide other MCNP6 users in the medical physics community to create similar beam models for biomedical dose estimation and research calculations for predicting dose to newly developed phantoms.

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

Article number | 108925 |

Journal | Applied Radiation and Isotopes |

Volume | 155 |

DOIs | |

State | Published - Jan 2020 |

### Fingerprint

### Keywords

- Clinical linear accelerator
- Computational modeling
- Medical physics
- Monte Carlo simulation
- Radiation oncology

### ASJC Scopus subject areas

- Radiation

### Cite this

*Applied Radiation and Isotopes*,

*155*, [108925]. https://doi.org/10.1016/j.apradiso.2019.108925

**Implementation of a simple clinical linear accelerator beam model in MCNP6 and comparison with measured beam characteristics.** / Gray, Tara; Bassiri, Nema; Kirby, Neil; Stathakis, Sotirios; Mayer, Kathryn M.

Research output: Contribution to journal › Article

*Applied Radiation and Isotopes*, vol. 155, 108925. https://doi.org/10.1016/j.apradiso.2019.108925

}

TY - JOUR

T1 - Implementation of a simple clinical linear accelerator beam model in MCNP6 and comparison with measured beam characteristics

AU - Gray, Tara

AU - Bassiri, Nema

AU - Kirby, Neil

AU - Stathakis, Sotirios

AU - Mayer, Kathryn M.

PY - 2020/1

Y1 - 2020/1

N2 - Monte Carlo N-Particle 6 (MCNP6) is the latest version of Los Alamos National Laboratory's powerful Monte Carlo software designed to compute general photon, neutron, and electron transport using stochastic algorithms. Here we provide a case study of modeling the photon beam of a Varian 600C Clinical Linear Accelerator (linac), which is used to deliver radiation therapy, along with a comparison to experimentally measured beam characteristics. The source definition parameters in MCNP6, including the energy spectrum and angular spectrum of the photons, secondary and tertiary collimators, and a water phantom that tallied dose delivered at different points along the phantom are included. The experimental data for comparison was in the form of a percent depth dose curve as well as crossline and inline beam profiles. Experimental depth dose curve and beam profiles were acquired using a standard 0.125 cc ion chamber within a water phantom. In the computational model, the simulated depth dose curve was computed by tallying the total energy deposited in a stack of vertical slices down the depth of the phantom for percent depth dose curves. The simulated beam profiles were computed in a similar fashion, by tallying the energy deposited in a horizontal row, both in the x- and y-directions of cubic cells located at various depths. For the percent depth dose curve, a mean absolute percentage difference of 1.02%, 1.07%, and 1.94% were calculated for field sizes of 5 × 5 cm2, 10 × 10 cm2 and 20 × 20 cm2, respectively, between the model and experimental measurements were calculated. We present our model as an example to guide other MCNP6 users in the medical physics community to create similar beam models for biomedical dose estimation and research calculations for predicting dose to newly developed phantoms.

AB - Monte Carlo N-Particle 6 (MCNP6) is the latest version of Los Alamos National Laboratory's powerful Monte Carlo software designed to compute general photon, neutron, and electron transport using stochastic algorithms. Here we provide a case study of modeling the photon beam of a Varian 600C Clinical Linear Accelerator (linac), which is used to deliver radiation therapy, along with a comparison to experimentally measured beam characteristics. The source definition parameters in MCNP6, including the energy spectrum and angular spectrum of the photons, secondary and tertiary collimators, and a water phantom that tallied dose delivered at different points along the phantom are included. The experimental data for comparison was in the form of a percent depth dose curve as well as crossline and inline beam profiles. Experimental depth dose curve and beam profiles were acquired using a standard 0.125 cc ion chamber within a water phantom. In the computational model, the simulated depth dose curve was computed by tallying the total energy deposited in a stack of vertical slices down the depth of the phantom for percent depth dose curves. The simulated beam profiles were computed in a similar fashion, by tallying the energy deposited in a horizontal row, both in the x- and y-directions of cubic cells located at various depths. For the percent depth dose curve, a mean absolute percentage difference of 1.02%, 1.07%, and 1.94% were calculated for field sizes of 5 × 5 cm2, 10 × 10 cm2 and 20 × 20 cm2, respectively, between the model and experimental measurements were calculated. We present our model as an example to guide other MCNP6 users in the medical physics community to create similar beam models for biomedical dose estimation and research calculations for predicting dose to newly developed phantoms.

KW - Clinical linear accelerator

KW - Computational modeling

KW - Medical physics

KW - Monte Carlo simulation

KW - Radiation oncology

UR - http://www.scopus.com/inward/record.url?scp=85075505376&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85075505376&partnerID=8YFLogxK

U2 - 10.1016/j.apradiso.2019.108925

DO - 10.1016/j.apradiso.2019.108925

M3 - Article

C2 - 31757713

AN - SCOPUS:85075505376

VL - 155

JO - Applied Radiation and Isotopes

JF - Applied Radiation and Isotopes

SN - 0969-8043

M1 - 108925

ER -