Photoacoustic intra-operative nodal staging using clinically approved superparamagnetic iron oxide nanoparticles

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Detection of tumor metastases in the lymphatic system is essential for accurate staging of various malignancies, however fast, accurate and cost-effective intra-operative evaluation of the nodal status remains difficult to perform with common available medical imaging techniques. In recent years, numerous studies have confirmed the additional value of superparamagnetic iron oxide dispersions (SPIOs) for nodal staging purposes, prompting the clearance of different SPIO dispersions for clinical practice. We evaluate whether a combination of photoacoustic (PA) imaging and a clinically approved SPIO dispersion, could be applied for intra-operative nodal staging. Metastatic adenocarcinoma was inoculated in Copenhagen rats for 5 or 8 days. After SPIO injection, the lymph nodes were photoacoustically imaged both in vivo and ex vivo whereafter imaging results were correlated with MR and histology. Results were compared to a control group without tumor inoculation. In the tumor groups clear irregularities, as small as 1 mm, were observed in the PA contrast pattern of the nodes together with an decrease of PA response. These irregularities could be correlated to the absence of contrast in the MR images and could be linked to metastatic deposits seen in the histological slides. The PA and MR images of the control animals did not show these features. We conclude that the combination of photoacoustic imaging with a clinically approved iron oxide nanoparticle dispersion is able to detect lymph node metastases in an animal model. This approach opens up new possibilities for fast intra-operative nodal staging in a clinical setting.
Original languageEnglish
Title of host publicationPhotons Plus Ultrasound
Subtitle of host publicationImaging and Sensing 2013
EditorsAlexander A. Oraevsky, Lihong V. Wang
Place of PublicationBellingham, WA
Number of pages1
ISBN (Print)978-0-81949-350-7
Publication statusPublished - 2 Feb 2013
EventPhotons plus ultrasound : imaging and sensing 2013 - San Francisco, United States
Duration: 3 Feb 20135 Feb 2013

Publication series

NameProceedings of SPIE
ISSN (Print)1605-7422


ConferencePhotons plus ultrasound : imaging and sensing 2013
Country/TerritoryUnited States
CitySan Francisco


  • nodal staging
  • EWI-23111
  • Photoacoustics
  • METIS-297603
  • BSS-Neurotechnology and cellular engineering
  • Nanoparticles
  • IR-86789
  • SPIO dispersion

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