title: Nonionizing photoacoustic cystography with near-infrared absorbing gold nanostructures as optical-opaque tracers.
abstract: OBJECTIVE
  The objectives of this study were to demonstrate nonionizing photoacoustic tomography (PAT) of bladders with near-infrared absorbing gold nanocages (GNCs) as an optical-turbid tracer and to investigate the fate of GNCs after photoacoustic imaging.
  
  
  METHODS
  The rats' bladders were visualized using PAT after transurethral injection of 2-nM GNCs. The fate of GNCs in the bladders was investigated. Spectroscopic PAT was applied to identify GNC-filled bladders in vivo and study biodistribution ex vivo.
  
  
  RESULTS
  Rats' bladders filled with GNCs were successfully imaged using a PAT system. The photoacoustic amplitude was enhanced by approximately 2240%. Both in vivo and ex vivo PAT results reveal that no accumulation of GNCs in the bladder and kidney was observed, and were validated with inductively coupled plasma mass spectrometry.
  
  
  CONCLUSIONS
  The PAT with transurethral injection of GNCs provides two crucial safety features for clinical translation: no radiation exposure and no long-term heavy metal accumulation.
authors.affiliation: Department of Creative IT Engineering, Pohang University of Science & Technology, Pohang, 790-784, Republic of Korea.
authors.forename: Mansik
authors.initials: M
authors.lastname: Jeon
authors.forename: Samir
authors.initials: S
authors.lastname: Jenkins
authors.forename: Junghwan
authors.initials: J
authors.lastname: Oh
authors.forename: Jeehyun
authors.initials: J
authors.lastname: Kim
authors.forename: Tara
authors.initials: T
authors.lastname: Peterson
authors.forename: Jingyi
authors.initials: J
authors.lastname: Chen
authors.forename: Chulhong
authors.initials: C
authors.lastname: Kim
mesh_terms: D000818:Animals; D006046:Gold / Q000008:administration & dosage / Q000493:pharmacokinetics; D007267:Injections; D053768:Metal Nanoparticles / Q000008:administration & dosage / Q000737:chemistry; D050997:Nanomedicine; D061088:Photoacoustic Techniques / Q000295:instrumentation / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013054:Spectrophotometry, Atomic; D019265:Spectroscopy, Near-Infrared; D014054:Tomography / Q000295:instrumentation / Q000379:methods*; D014521:Urethra; D001743:Urinary Bladder / Q000033:anatomy & histology* / Q000378:metabolism
chemical_list: D006046:Gold
keywords: cystography; gold nanocages; gold nanostructures; photoacoustic cystography; photoacoustic tomography; urinary tract infection