Combining multispectral polarized light imaging and confocal microscopy for localization of nonmelanoma skin cancer

Multispectral polarized light imaging (MSPLI) enables rapid inspection of a superficial tissue layer over large surfaces, but does not provide information on cellular microstructure. Confocal microscopy (CM) allows imaging within turbid media with resolution comparable to that of histology, but suffers from a small field of view. In practice, pathologists use microscopes at low and high power to view tumor margins and cell features, respectively. Therefore, we study the combination of CM and MSPLI for demarcation of nonmelanoma skin cancers. Freshly excised thick skin samples with nonmelanoma cancers are rapidly stained with either toluidine or methylene blue dyes, rinsed in acetic acid, and imaged using MSPLI and CM. MSPLI is performed at 630, 660, and 750 nm. The same specimens are imaged by reflectance CM at 630, 660, and 830 nm. Results indicate that CM and MSPLI images are in good correlation with histopathology. Cytological features are identified by CM, and tumor margins are delineated by MSPLI. A combination of MSPLI and CM appears to be complementary. This combined in situ technique has potential to guide cancer surgery more rapidly and at lower cost than conventional histopathology.