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Proceedings Paper

Locally increased mortality of gamma-irradiated cells in presence of lanthanide-halide nanoparticles
Author(s): Nathan J. Withers; Natasha N Glazener; John B. Plumley; Brian A. Akins; Antonio C. Rivera; Nathaniel C. Cook; Gennady A. Smolyakov; Graham S. Timmins; Marek Osiński
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Paper Abstract

Cerium-doped lanthanum fluoride colloidal nanocrystals (NCs) offer a way to improve radiation therapy through the enhanced absorption of high-energy photons. The use of Monte Carlo simulation allows the direct calculation of the macroscopic dose enhancement factor (MDEF), a figure of merit for NC-enhanced radiation therapy. Our simulations of brachytherapy using an Ir-192 source agree with previous work on the subject for gold NCs and show effectiveness of LaF3:10%Ce NCs to be approximately 50% that of gold. Polyethylene-glycol-capped LaF3:10%Ce NCs were synthesized, isolated, suspended in phosphate buffered saline (PBS), and characterized with transmission electron microscopy, dynamic light scattering, photoluminescence spectroscopy, and absorption spectroscopy. LaF3:10%Ce NCs were used in radiation dose enhancement experiments that involved an incoming 662 keV gamma flux from dual Cs-137 sources to test the mortality of Saccharomyces cerevisiae. At a small loading of 1.8 mg NC/g of PBS, the experiment did not produce a measurable increased mortality. To understand the results, additional Monte Carlo simulations revealed that the photon energy of 662 keV gamma rays is far from optimal, providing only a 4% increase in dose for a concentration of 18 mg of NCs / g of PBS. Further simulations showed that the optimal photon energy for this technique is 60 keV, tripling the absorbed dose for a concentration of 18 mg of NCs / g of PBS.

Paper Details

Date Published: 16 February 2011
PDF: 12 pages
Proc. SPIE 7909, Colloidal Quantum Dots/Nanocrystals for Biomedical Applications VI, 79090L (16 February 2011); doi: 10.1117/12.877029
Show Author Affiliations
Nathan J. Withers, The Univ. of New Mexico (United States)
Natasha N Glazener, The Univ. of New Mexico (United States)
John B. Plumley, The Univ. of New Mexico (United States)
Brian A. Akins, The Univ. of New Mexico (United States)
Antonio C. Rivera, The Univ. of New Mexico (United States)
Nathaniel C. Cook, The Univ. of New Mexico (United States)
Gennady A. Smolyakov, The Univ. of New Mexico (United States)
Graham S. Timmins, The Univ. of New Mexico (United States)
Marek Osiński, The Univ. of New Mexico (United States)


Published in SPIE Proceedings Vol. 7909:
Colloidal Quantum Dots/Nanocrystals for Biomedical Applications VI
Wolfgang J. Parak; Kenji Yamamoto; Marek Osinski, Editor(s)

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