Multiphoton coherence domain molecular imaging with pump-probe optical coherence microscopy.

We have developed a high-resolution molecular imaging technique, pump-probe optical coherence microscopy (PPOCM), based on the fusion of pump-probe spectroscopy and optical coherence microscopy. We have demonstrated the prototype system on a fixed human skin sample containing a nodular melanoma. The results indicate that the PPOCM can clearly provide a strong contrast between the melanotic and amelanotic regions. Potential applications of the PPOCM imaging of melanin include the early diagnosis of melanoma and the mapping of tumor margins during excision. The technique may in general be applied to any biological chromophore with a known absorption spectrum.