In vivo photoactivation without "light": use of Cherenkov radiation to overcome the penetration limit of light

Mol Imaging Biol. 2012 Apr;14(2):156-62. doi: 10.1007/s11307-011-0489-z.


Purpose: The poor tissue penetration of visible light has been a major barrier for optical imaging, photoactivatable conversions, and photodynamic therapy for in vivo targets with depths beyond 10 mm. In this report, as a proof-of-concept, we demonstrated that a positron emission tomography (PET) radiotracer, 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)FDG), could be used as an alternative light source for photoactivation.

Procedures: We utilized (18)FDG, which is a metabolic activity-based PET probe, as a source of light to photoactivate caged luciferin in a breast cancer animal model expressing luciferase.

Results: Bioluminescence produced from luciferin allowed for the real-time monitoring of Cherenkov radiation-promoted uncaging of the substrate.

Conclusion: The proposed method may provide a very important option for in vivo photoactivation, in particular for activation of photosensitizers for photodynamic therapy and eventually for combining radioisotope therapy and photodynamic therapy.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Chromatography, Liquid
  • Diagnostic Imaging / methods*
  • Elementary Particles*
  • Firefly Luciferin / chemistry
  • Firefly Luciferin / metabolism
  • Fluorodeoxyglucose F18
  • Humans
  • Light*
  • Luminescent Measurements
  • Mass Spectrometry
  • Mice
  • Mice, Nude
  • Solutions


  • Solutions
  • Fluorodeoxyglucose F18
  • Firefly Luciferin