Fiber-optic middle infrared evanescent wave spectroscopy for early detection of melanoma

Melanoma is responsible for most of the fatalities from skin cancer diseases. Yet, there is no reliable method for a noninvasive early detection of skin cancers. We developed a Fiber-optic Evanescent wave Spectroscopy (FEWS) method based on a Fourier Transform Mid-IR (FTIR) spectrometer and on U shaped silver halide (AgClBr) fibers that are highly transparent in the mid-IR. We measured suspicious lesions on patients, before their excision. The central part of the bent fiber touched the lesion and the mid-IR absorption of this area was measured in situ and in real time. As a background, the same measurement was performed on healthy nearby skin. All discomfort to the patient was avoided. The lesions were then examined by conventional means. Histopathology revealed 5 melanoma tumors out of 90 patients and clear and repeating spectral differences between background and lesion are seen in all patients. We continue to accumulate spectral data of melanoma and of other pathologies, for better statistics and for characterization of other types of skin cancer. It is hoped that this non-invasive method for an early detection and diagnosis of skin cancer will replace biopsy and revolutionize this field.