Real-time augmented reality for delineation of surgical margins during neurosurgery using autofluorescence lifetime contrast

Alba Alfonso-Garcia, Julien Bec, Shamira Sridharan Weaver, Brad Hartl, Jakob Unger, Matthew Bobinski, Mirna Lechpammer, Fady Girgis, James Boggan, Laura Marcu

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Current clinical brain imaging techniques used for surgical planning of tumor resection lack intraoperative and real-time feedback; hence surgeons ultimately rely on subjective evaluation to identify tumor areas and margins. We report a fluorescence lifetime imaging (FLIm) instrument (excitation: 355 nm; emission spectral bands: 390/40 nm, 470/28 nm, 542/50 nm and 629/53 nm) that integrates with surgical microscopes to provide real-time intraoperative augmentation of the surgical field of view with fluorescent derived parameters encoding diagnostic information. We show the functionality and safety features of this instrument during neurosurgical procedures in patients undergoing craniotomy for the resection of brain tumors and/or tissue with radiation damage. We demonstrate in three case studies the ability of this instrument to resolve distinct tissue types and pathology including cortex, white matter, tumor and radiation-induced necrosis. In particular, two patients with effects of radiation-induced necrosis exhibited longer fluorescence lifetimes and increased optical redox ratio on the necrotic tissue with respect to non-affected cortex, and an oligodendroglioma resected from a third patient reported shorter fluorescence lifetime and a decrease in optical redox ratio than the surrounding white matter. These results encourage the use of FLIm as a label-free and non-invasive intraoperative tool for neurosurgical guidance.

Original languageEnglish (US)
Article numbere201900108
JournalJournal of Biophotonics
StateAccepted/In press - Jan 1 2019


  • brain tumor
  • fluorescence lifetime
  • imaging
  • neurosurgery
  • radiation-induced necrosis

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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