Study of the effect of ceramic Ta2O5 nanoparticle distribution on cellular dose enhancement in a kilovoltage photon field. Issue 10 (October 2016)

• Record Type: Journal Article
• Authors: McKinnon, Sally; Engels, Elette; Tehei, Moeava; Konstantinov, Konstantin; Corde, Stéphanie; Oktaria, Sianne; Incerti, Sebastien; Lerch, Michael; Rosenfeld, Anatoly; Guatelli, Susanna
• Is Part Of: Physica medica. Volume 32:Issue 10(2016)
• Page Start: 1216
• Page End: 1224
• Publication Date: 2016-10
• Subjects: Ceramic nanoparticles -- Dose enhancement -- X-ray radiotherapy -- Monte Carlo method -- Geant4; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2016.09.006
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: Study of the dose enhancement by the novel nanoparticle (NP) Ta2 O5 in X-ray kVp beam. A realistic distribution of Ta2 O5 NPs shells around cell nuclei in a cell population is modelled. Ta2 O5 NPs enhance most when close to the nucleus and effect plateaus for shell thickness above 5 μm. Morphology, concentration and non-uniform distribution of NPs play a key role in dose enhancement. Justify lack of increased dose enhancement observed in experiments increasing concentration. Abstract: The application of nanoparticles (NPs) in radiotherapy is an increasingly attractive technique to improve clinical outcomes. The internalisation of NPs within the tumour cells enables an increased radiation dose to critical cellular structures. The purpose of this study is to investigate, by means of Geant4 simulations, the dose enhancement within a cell population irradiated with a 150 kVp photon field in the presence of a varying concentration of tantalum pentoxide (Ta2 O5 ) NP aggregates, experimentally observed to form shells within tumour cells. This scenario is compared to the more traditionally simulated homogeneous solution of NP material in water with the same weight fraction of Ta2 O5, as well as to a cell population without NPs present. The production of secondary electrons is enhanced by increased photoelectric effect interactions within the high-Z material and this is examined in terms of their kinetic energy spectra and linear energy transfer (LET) with various NP distributions compared to water. Our results indicate that the shell formation scenario limits the dose enhancement at 150 kVp. The underlying mechanism for this limit is discussed.