Neutron Production in The Scattering S250 Mevion Proton-Therapy System

TL;DR

This paper compares and analyzes neutron dose measurements in proton therapy, using Monte Carlo simulations and existing data to establish a convergence range for neutron-absorbed doses, which are relevant for understanding secondary cancer risks.

Contribution

It provides a comparative analysis of neutron dose values in proton therapy using Monte Carlo calculations and previous measurements, clarifying the range of neutron doses.

Findings

Neutron dose values vary widely across different measurement methods.

Monte Carlo calculations help unify the range of neutron dose estimates.

The study suggests a convergence range for neutron-absorbed doses in proton therapy.

Abstract

Secondary radiation in a radiation therapy environment is considered a cause for post-treatment side effects including secondary carcinogenesis. In a proton-therapy setup, neutrons deliver a considerable extra dose to the patient. Various measurements and calculations of neutron dose suggest a wide range of values for this quantity. This paper provides a comparison between the previously published values and analyzes the Monte Carlo calculated neutron dose from the present work using the neutron cross-section data. The purpose is to provide a range for the convergence of several neutron-absorbed dose data points (e.g. 3.94 mSv/Gy in a Bonner sphere measurement and 0.4 mSv/Gy in a SWENDI measurement) in previous works of other authors.