Skin diseases are one of the most common pathologies worldwide. Among them skin cancer, and in particular non-melanoma skin cancer (NMSC) is especially relevant from a public health perspective, being the most common cancer in Caucasian populations.
NMSC is usually used to refer to the two types of skin cancer which account for 95% of all NMSC: basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).
The estimated direct cost of treating melanoma and non-melanoma skin cancers in the U.S. is more than $11B annually. Early detection and diagnosis can greatly improve the prognosis and also reduce the total cost to national health systems. In this respect, actinic keratosis (AK) is a non-malignant skin lesion which has been identified as a precursor of SCC, with 6-10% of AK developing into invasive SCC.
During the last decades a number of imaging techniques have been developed to overcome the limitations of direct visual inspection for dermatological diagnosis. Nevertheless, skin biopsies and subsequent histopathological examination are still needed in the majority of cases and are nowadays considered the gold standard for morphological investigation of the skin. However a biopsy has some disadvantages: it is an invasive procedure, it is expensive and time consuming, it only provides a temporal and spatial snapshot during the course of the disease and it is not suitable for lesion monitoring through repeated measurements.
Hence, there is a strong demand for noninvasive, high-resolution and in-vivo imaging techniques.