title: Local dose enhancement of proton therapy by ceramic oxide nanoparticles investigated with Geant4 simulations.
abstract: Nanoparticles (NPs) have been shown to enhance X-ray radiotherapy and proton therapy of cancer. The effectiveness of radiation damage is enhanced in the presence of high atomic number (high-Z) NPs due to increased production of low energy, higher linear energy transfer (LET) secondary electrons when NPs are selectively internalized by tumour cells. This work quantifies the local dose enhancement produced by the high-Z ceramic oxide NPs Ta2O5and CeO2, in the target tumour, for the first time in proton therapy, by means of Geant4 simulations. The dose enhancement produced by the ceramic oxides is compared against gold NPs. The energy deposition on a nanoscale around a single nanoparticle of 100nm diameter is investigated using the Geant4-DNA extension to model particle interactions in the water medium. Enhancement of energy deposition in nano-sized shells of water, local to the NP boundary, ranging between 14% and 27% was observed for proton energies of 5MeV and 50MeV, depending on the NP material. Enhancement of electron production and energy deposition can be correlated to the direct DNA damage mechanism if the NP is in close proximity to the nucleus.
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia.
authors.forename: Sally
authors.initials: S
authors.lastname: McKinnon
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia. Electronic address: susanna@uow.edu.au.
authors.forename: Susanna
authors.initials: S
authors.lastname: Guatelli
authors.affiliation: CNRS/IN2P3, Centre d'Etudes Nucléaires de Bordeaux-Gradignan, UMR-5797, chemin du solarium, 33175 Gradignan, France; Université Bordeaux, Centre d'Etudes Nucléaires de Bordeaux-Gradignan, UMR-5797, chemin du solarium, 33175 Gradignan, France.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Incerti
authors.affiliation: Geant4 Associates International Ltd, United Kingdom; Ecoanalytica, 119899 Moscow, Russian Federation.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Ivanchenko
authors.affiliation: Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; Institute for Superconducting and Electronic Materials, University of Wollongong, NSW, Australia.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Konstantinov
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Radiation Oncology Department, Prince of Wales Hospital, Randwick, NSW, Australia.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Corde
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Lerch
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; Centre for Medical and Molecular Bioscience, University of Wollongong, NSW, Australia.
authors.forename: Moeava
authors.initials: M
authors.lastname: Tehei
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia; Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Rosenfeld
mesh_terms: D002563:Cerium / Q000737:chemistry / Q000494:pharmacology; D006046:Gold / Q000737:chemistry; D006801:Humans; D008297:Male; D053768:Metal Nanoparticles / Q000737:chemistry; D009010:Monte Carlo Method; D053758:Nanoparticles; D010087:Oxides / Q000737:chemistry* / Q000494:pharmacology*; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D061766:Proton Therapy / Q000379:methods*; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D013635:Tantalum / Q000737:chemistry / Q000494:pharmacology
chemical_list: D010087:Oxides; D002563:Cerium; C030583:ceric oxide; D013635:Tantalum; D006046:Gold; C078151:tantalum oxide
keywords: Geant4; Monte Carlo; Nanoparticles; Proton therapy