MCNP5 evaluation of photoneutron production from the Alexandria University 15 MV Elekta Precise medical LINAC

W M Abou-Taleb; M H Hassan; E A El Mallah; S M Kotb

doi:10.1016/j.apradiso.2018.01.036

MCNP5 evaluation of photoneutron production from the Alexandria University 15 MV Elekta Precise medical LINAC

Appl Radiat Isot. 2018 May:135:184-191. doi: 10.1016/j.apradiso.2018.01.036.

Authors

W M Abou-Taleb¹, M H Hassan², E A El Mallah³, S M Kotb⁴

Affiliations

¹ Physics and Chemistry Department, Faculty of Education, Alexandria University, Alexandria, Egypt. Electronic address: [email protected].
² Nuclear and Radiation Engineering Department, Alexandria University, Egypt. Electronic address: [email protected].
³ Physics Department, Faculty of Science, Alexandria University, Alexandria, Egypt. Electronic address: [email protected].
⁴ Physics and Chemistry Department, Faculty of Education, Alexandria University, Alexandria, Egypt. Electronic address: [email protected].

PMID: 29413836
DOI: 10.1016/j.apradiso.2018.01.036

Abstract

Photoneutron production, and the dose equivalent, in the head assembly of the 15 MV Elekta Precise medical linac; operating in the faculty of Medicine at Alexandria University were estimated with the MCNP5 code. Photoneutron spectra were calculated in air and inside a water phantom to different depths as a function of the radiation field sizes. The maximum neutron fluence is 3.346×10^-9 n/cm²-e for a 30×30 cm² field size to 2-4 cm-depth in the phantom. The dose equivalent due to fast neutron increases as the field size increases, being a maximum of 0.912 ± 0.05 mSv/Gy at depth between 2 and 4 cm in the water phantom for 40×40 cm² field size. Photoneutron fluence and dose equivalent are larger to 100 cm from the isocenter than to 35 cm from the treatment room wall.

Keywords: Dose equivalent; Elekta Linac; MCNP5; Photoneutrons.