Differentiation of cutaneous melanoma from surrounding skin using laser-induced breakdown spectroscopy

Abstract

Laser-induced breakdown spectroscopy (LIBS) has the potential to be used as a surgical tool for simultaneous tissue ablation and elemental analysis of the ablated tissue. LIBS may be used to distinguish melanoma lesions from the surrounding dermis based on the quantitative difference of elements within melanoma lesions. Here, we measured the elements in homogenized pellets and real tissues from excised skin samples of melanoma-implanted mice. In addition, statistical analysis of LIBS spectra using principal component analysis and linear discriminant analysis was performed. Our results showed that this method had high detection sensitivity, highlighting the potential of this tool in clinical applications.

Mapping of cutaneous melanoma by femtosecond laser-induced breakdown spectroscopy

“…11 For the case of melanoma, we reported in our recent study that melanoma and surrounding dermis could be distinguished by LIBS with high sensitivity using Mg and Ca emission peaks as the biomarkers. 12 Although it was an early stage of research yet, this study confirmed that LIBS can be an effective method to identify melanoma from normal tissue.…”

“…On the contrary, the difference in pigment density between melanoma and dermis is considered to have little influence in the signal intensity change, because, in our previous study for LIBS analyses of melanoma with pellet and excised tissue samples, Mg intensity was found to be also higher in melanoma even after the absorption property difference between pigmented and nonpigmented regions was compensated by normalization. 12…”

“…Previously, we reported the LIBS data of melanoma and dermis measured using a nanosecond laser and a CCD spectrometer over a wide spectral range (200 to 900 nm). 12 The results showed that among the various detected elements (C, Mg, Ca, Na, H, O, N, and Cl), Mg and Ca showed significantly higher intensities in melanoma than in dermis, whereas other elements showed little difference. It was also shown that the Mg and Ca signals appeared at Mg (II) 279.553 nm, Mg (II) 280.170 nm, Ca (II) 393.366 nm, and Ca (II) 369.847 nm.…”

“…6 In contrast, the intensities of magnesium peaks, Mg(II) 279.553 þ 280.270 nm and Mg(I) 285.213 nm, of the pigmented melanoma were found to be significantly higher than those in the surrounding tissue, which reconfirmed our previous results. 12 Note that the silicon peak Si(I) 236.128 nm, obtained by ablating a bear silicon wafer, is also shown in Fig. 3 in order to show that the measured carbon and magnesium signals were not interfered by the substrate.…”

“…Although the spectral information itself in our previous study 12 is useful in determining the pathological state of the tissue, an elemental mapping image based on LIBS spectral intensity can provide a direct information to assess the skin cancer region and required margin during a surgical excision. In the case of Mohs micrographics surgery, LIBS elemental mapping may be applied to a sectioned tissue to rapidly create a map showing the cancer and normal tissue regions.…”