In vivo fluorescence lifetime tomography

Ralph E. Nothdurft, Sachin V. Patwardhan, Walter Akers, Yunpeng Ye, Samuel Achilefu, Joseph P. Culver

Research output: Contribution to journalArticlepeer-review

101 Scopus citations


Local molecular and physiological processes can be imaged in vivo through perturbations in the fluorescence lifetime (FLT) of optical imaging agents. In addition to providing functional information, FLT methods can quantify specific molecular events and multiplex diagnostic and prognostic information. We have developed a fluorescence lifetime diffuse optical tomography (DOT) system for in vivo preclinical imaging. Data is captured using a time-resolved intensified charge coupled device (ICCD) system to measure fluorescence excitation and emission in the time domain. Data is then converted to the frequency domain, and we simultaneously reconstruct images of yield and lifetime using an extension to the normalized Born approach. By using differential phase measurements, we demonstrate DOT imaging of short lifetimes (from 350ps) with high precision (±5ps). Furthermore, this system retains the efficiency, speed, and flexibility of transmission geometry DOT. We demonstrate feasibility of FLT-DOT through a progressive series of experiments. Lifetime range and repeatability are first measured in phantoms. Imaging of subcutaneous implants then verifies the FLT-DOT approach in vivo in the presence of inhomogeneous optical properties. Use in a common research scenario is ultimately demonstrated by imaging accumulation of a targeted near-infrared (NIR) fluorescent-labeled peptide probe (cypate-RGD) in a mouse with a subcutaneous tumor.

Original languageEnglish (US)
Article number024004
JournalJournal of biomedical optics
Issue number2
StatePublished - 2009
Externally publishedYes


  • diffusion
  • fluorescence
  • image reconstruction
  • imaging systems
  • tomography

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering


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