Open AccessShielding verification and neutron dose evaluation of the Mevion S250 proton therapy unit
Author(s) -
Prusator Michael T.,
Ahmad Salahuddin,
Chen Yong
Publication year - 2018
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12256
Subject(s) - isocenter , proton therapy , electromagnetic shielding , neutron , monte carlo method , cyclotron , proton , equivalent dose , physics , nuclear engineering , nuclear physics , nuclear medicine , medical physics , materials science , environmental science , medicine , optics , engineering , mathematics , statistics , imaging phantom , plasma , quantum mechanics
For passive scattering proton therapy systems, neutron contamination is the main concern both from an occupational and patient safety perspective. The Mevion S250 compact proton therapy system is the first of its kind, offering an in‐room cyclotron design which prompts more concern for shielding assessment. The purpose of this study was to accomplish an in‐depth evaluation of both the shielding design and in‐room neutron production at our facility using both Monte Carlo simulation and measurement. We found that the shielding in place at our facility is adequate, with simulated annual neutron ambient dose equivalents at 30 cm outside wall/door perimeter ranging from background to 0.07 mS v and measured dose equivalents ranging from background to 0.06 mS v. The in‐room measurements reveal that the H*/D decreases when the distance from isocenter and field size increases. Furthermore, the H*/D generally increases when the angle around isocenter increases. Our results from in‐room measurements show consistent trends with our Monte Carlo model of the Mevion system.