Phys Med Biol. 2013 Dec 21;58(24):8709-23. doi: 10.1088/0031-9155/58/24/8709.
Evaluation of neutron dose equivalent from the Mevion S250 proton accelerator: measurements and calculations.
Chen KL, Bloch CD, Hill PM, Klein EE.
Abstract
Neutron
production is of concern for proton therapy, especially for passive
scattering proton beam delivery methods. The levels of neutron dose
equivalent vary significantly with system design and treatment
parameters. The purpose of this study was to examine neutron dose
equivalent per therapeutic dose (H/D) around the Mevion S250 proton
therapy system, a novel design of proton therapy systems. The benchmark
comparisons between measurement and simulation were found to be within a
factor of 2 for most cases. The H/D values were evaluated as a function
of various parameters. The results showed that, at a standard reference
condition (10 × 10 cm(2) field size, distance 1 m detector-to-isocenter
lateral to the primary proton beam direction), the H/D values range
from 0.72 to 3.37 mSv Gy(-1) for all configurations studied. The H/D
values generally (1) decreased as the neutron detectors moved away from
the isocenter, (2) decreased with increasing aperture field sizes, (3)
increased with increasing angle from the initial beam axis and (4) were
independent of treatment nozzle position. The H/D trends were consistent
with other existing passive scattering proton accelerators reported in
the literature.
- PMID: 24301001 ©
