Monte Carlo study of out‐of‐field exposure in carbon‐ion radiotherapy: Organ doses in pediatric brain tumor treatment
Year: 2019
Type: article
Abstract: PURPOSE: To estimate out-of-field doses during carbon-ion radiotherapy (CIRT) for pediatric cerebellar ependymoma. METHODS: Given that the out-of-field dose of CIRT depends on beam parameters, we set them for treatment of typical pediatric cerebellar ependymoma based on a previous study. The out-of-field dose during CIRT for pediatric cerebellar ependymoma was then estimated using the Particle and Heavy-Ion Transport code System with Monte Carlo simulations and a computational phantom developed at the University of Florida. From the simulation results, out-of-field doses at dose equivalents of passive beam and active scanning beam CIRT were calculated and compared to the secondary neutron-equivalent dose of passive beam CIRT and proton therapy. RESULTS: The out-of-field dose equivalent decreases from 1.45 mSv/Gy (relative biological effectiveness - RBE) at the thyroid to 0.06 mSv/Gy (RBE) at the bladder, verifying decay as the distance from the treatment target increases. The out-of-field neutron-equivalent dose in organs per prescribed dose for passive beam CIRT is lower than that for passive beam proton therapy. Moreover, the out-of-field organ dose equivalent per prescribed dose for the active scanning beam CIRT is lower than that for the passive beam CIRT. CONCLUSIONS: Active scanning beam CIRT is promising for pediatric cerebellar ependymoma regarding out-of-field exposure, outperforming the comparison radiotherapy modalities.
Source: Medical Physics
DOI: 10.1002/mp.13864
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2979765630