Mapping of cutaneous melanoma by femtosecond laser-induced breakdown spectroscopy.

Surgical excision (Mohs micrographic surgery) is the standard procedure to treat a melanoma, in which an in situ histologic examination of sectioned skin is carried out repeatedly until no cancer cells are detected. The possibility to identify melanoma from the surrounding skin by femtosecond laser-induced breakdown spectroscopy (fs-LIBS) is investigated. For experiments, melanoma induced on a hairless mouse by injection of B16/F10 murine melanoma cell was sampled in the form of frozen tissue sections as in Mohs surgery and analyzed by fs-LIBS (λ  =  1030  nm, τ  =  550  fs). For analysis, the magnesium signal normalized by carbon intensity was utilized to construct an intensity map around the cancer, including both melanoma and surrounding dermis. The intensity map showed a close match to the optically observed morphological and histological features near the cancer region. The results showed that when incorporated into the existing micrographic surgery procedure, fs-LIBS could be a useful tool for histopathologic interpretation of skin cancer possibly with significant reduction of histologic examination time.