title: Detection of posteriorly located breast tumors using gold nanoparticles: a breast-mimicking phantom study.
abstract: BACKGROUND
  Accurately depicting breast tumors located posteriorly, close to the chest wall musculature, with conventional mammography is a technical challenge.
  
  
  OBJECTIVE
  This study demonstrates the proof of concept of an x-ray fluorescence mapping (XFM) technique to address this issue.
  
  
  METHODS
  A tissue-equivalent gel phantom is designed to mimic structures in the central part of a compressed breast. The posterior aspect of the breast and adjacent pectoralis major muscle are represented by another 10-mm-thickness breast tissue simulation phantom (BR12) that is attached to the back of the gel phantom as a region of interest (ROI). Two gold nanoparticle (GNP) solutions are embedded into the ROI to simulate varying GNP uptake within breast lesions. The ROI is imaged through performing the XFM technique with an x-ray pencil-beam and a single spectrometer.
  
  
  RESULTS
  A 2D mapping of the middle plane in the ROI demonstrates feasibility and matches well the known spatial distribution and different GNP concentrations. 3D reconstruction of the ROI is easily rendered by repeating the 2D mapping process.
  
  
  CONCLUSIONS
  XFM system geometry and its insensitivity to attenuation coefficients of breast tissue components are unique characteristics that may complement conventional mammography and improve the detection of breast cancers located posteriorly, adjacent to or overlying the chest wall musculature.
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Ren
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Radiology, University of Iowa, Iowa City, IA, USA.
authors.forename: Laurie L
authors.initials: LL
authors.lastname: Fajardo
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Li
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
mesh_terms: D001943:Breast Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D004867:Equipment Design; D005260:Female; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008327:Mammography / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008954:Models, Biological; D019047:Phantoms, Imaging; D013052:Spectrometry, X-Ray Emission / Q000295:instrumentation / Q000379:methods*
chemical_list: D006046:Gold
keywords: Breast cancer detection; breast-mimicking phantom; chest wall musculature; gold nanoparticles (GNPs); posteriorly located breast tumors; x-ray fluorescence mapping (XFM)