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Title: Brachytherapy Application With In Situ Dose Painting Administered by Gold Nanoparticle Eluters

Purpose: Recent studies show promise that administering gold nanoparticles (GNP) to tumor cells during brachytherapy could significantly enhance radiation damage to the tumor. A new strategy proposed for sustained administration of the GNP in prostate tumors is to load them into routinely used brachytherapy spacers for customizable in situ release after implantation. This in silico study investigated the intratumor biodistribution and corresponding dose enhancement over time due to GNP released from such GNP-loaded brachytherapy spacers (GBS). Method and Materials: An experimentally determined intratumoral diffusion coefficient (D) for 10-nm nanoparticles was used to estimate D for other sizes by using the Stokes-Einstein equation. GNP concentration profiles, obtained using D, were then used to calculate the corresponding dose enhancement factor (DEF) for each tumor voxel, using dose painting-by-numbers approach, for times relevant to the considered brachytherapy sources' lifetimes. The investigation was carried out as a function of GNP size for the clinically applicable low-dose-rate brachytherapy sources iodine-125 (I-125), palladium-103 (Pd-103), and cesium-131 (Cs-131). Results: Results showed that dose enhancement to tumor voxels and subvolumes during brachytherapy can be customized by varying the size of GNP released or eluted from the GBS. For example, using a concentration of 7 mg/g GNP, significant DEF (>20%)more » could be achieved 5 mm from a GBS after 5, 12, 25, 46, 72, 120, and 195 days, respectively, for GNP sizes of 2, 5, 10, 20, 30, and 50 nm and for 80 nm when treating with I-125. Conclusions: Analyses showed that using Cs-131 provides the highest dose enhancement to tumor voxels. However, given its relatively longer half-life, I-125 presents the most flexibility for customizing the dose enhancement as a function of GNP size. These findings provide a useful reference for further work toward development of potential new brachytherapy application with in situ dose painting administered via gold nanoparticle eluters for prostate cancer.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ; ;  [4] ;  [3] ; ; ;  [4] ;  [2] ;  [3]
  1. Department of Sciences, Wentworth Institute of Technology, Boston, Massachusetts (United States)
  2. Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts (United States)
  3. (United States)
  4. Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts (United States)
Publication Date:
OSTI Identifier:
22458606
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 91; Journal Issue: 2; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ADMINISTRATIVE PROCEDURES; BRACHYTHERAPY; CESIUM 131; CONCENTRATION RATIO; DOSE RATES; FLEXIBILITY; GOLD; HALF-LIFE; IODINE 125; NANOPARTICLES; NEOPLASMS; PALLADIUM 103; PROSTATE; RADIATION DOSES; RADIATION EFFECTS; TUMOR CELLS