title: Nanoparticle location and material dependent dose enhancement in X-ray radiation therapy.
abstract: Nanoparticles of high atomic number (Z) materials can act as radiosensitizers to enhance radiation dose delivered to tumors. An analytical approach is used to calculate dose enhancements to tumor endothelial cells and their nuclei for a series of nanoparticles (bismuth, gold and platinum) located at different locations relative to nuclei by considering contributions from both photoelectrons and Auger electrons. The ratio of the dose delivered to cells with and without the nanoparticles is known as the dose enhancement factor (DEF). DEFs depend on material composition, size and location of nanoparticles with respect to the cell and the nucleus. Energy of irradiating X-ray beam affects X-ray absorption by nanoparticles and plays an important role in dose enhancements. For diagnostic X-ray sources, bismuth nanoparticles provide higher dose enhancements than gold and platinum nanoparticles for a given nanoparticle size, concentration and location. The highest DEFs are achieved for nanoparticles located closest to the nucleus where energy depositions from short range Auger electrons are maximum. With nanoparticles ranging in diameter between 2-400 nm, the dose enhancement increases with decrease in particle size. The results are useful in finding optimized conditions for nanoparticle enhanced X-ray radiation therapy of cancer.
authors: NanoScience Technology Center, University of Central Florida, Orlando FL 32826 USA ; School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, FL 32826 USA.
authors: Mainul
authors: M
authors: Hossain
authors: Ming
authors: M
authors: Su
references: Appl Phys Lett. 2011 May 9;98(19):193702
references: 21915155
references: Rep Pract Oncol Radiother. 2010 Oct 08;15(6):176-80
references: 24376946
references: Nat Mater. 2006 Feb;5(2):118-22
references: 16444262
references: J Am Chem Soc. 2010 Feb 10;132(5):1517-9
references: 20085324
references: Phys Med Biol. 2004 Sep 21;49(18):N309-15
references: 15509078
references: Int J Radiat Oncol Biol Phys. 2011 Sep 1;81(1):270-6
references: 21163591
references: Radiat Res. 1970 Jun;42(3):451-70
references: 5463516
references: J Phys Chem B. 2007 Oct 11;111(40):11622-5
references: 17854220
references: Radiat Res. 1969 Apr;38(1):7-33
references: 5777999
references: Angew Chem Int Ed Engl. 2011 Dec 16;50(51):12308-11
references: 22028313
references: Recent Pat Drug Deliv Formul. 2007;1(1):37-51
references: 19075873
references: Mutat Res. 2010 Apr-Jun;704(1-3):123-31
references: 20074660
references: Nanotechnology. 2009 Sep 16;20(37):375101
references: 19706948
references: J Pharm Pharmacol. 2008 Aug;60(8):977-85
references: 18644191
references: Radiat Res. 2010 Jun;173(6):719-28
references: 20518651
references: Nanotechnology. 2010 Feb 26;21(8):85103
references: 20101074
references: Phys Med Biol. 2009 Aug 21;54(16):4889-905
references: 19636084
references: Nanomedicine. 2009 Jun;5(2):136-42
references: 19480049
references: Med Phys. 2012 Jan;39(1):392-8
references: 22225308
references: Phys Med Biol. 2010 Nov 7;55(21):6533-48
references: 20959684
references: Phys Med Biol. 2005 Aug 7;50(15):N163-73
references: 16030374
references: Med Phys. 2010 Jul;37(7):3809-16
references: 20831089
references: J ICRU. 2005 Dec;5(2):21-4
references: 24170871
references: Sci Rep. 2011;1:18
references: 22355537
references: Phys Med Biol. 2011 Aug 7;56(15):4631-47
references: 21734337
references: Phys Med Biol. 2010 Jun 7;55(11):3045-59
references: 20463371