Raman spectroscopy assisted diagnosis and photodynamic therapy efficacy evaluation of actinic keratosis: Case report

Actinic keratosis (AK), a precancerous skin lesion with malignant potential, demands timely diagnosis and effective treatment monitoring. Aminolevulinic acid photodynamic therapy (ALA-PDT) is the recommended treatment for AK, but there is currently a lack of methods to evaluate the effectiveness of treatment. Raman spectroscopy might be a promising tool for non-invasive diagnosis of AK and dynamic detection of PDT efficacy. This article reports a 77-year-old female patient with AK who received Raman spectroscopy detection and successful PDT. Utilizing a portable Raman spectrometer, distinct spectral features were identified: Raman band at 1688 cm⁻¹, attributed to elastin accumulation in AK lesions, and Raman band at 1615 cm⁻¹, associated with tyrosine, a melanin precursor. The patient underwent three sessions of ALA-PDT and Raman spectra were acquired after each session to reveal progressive changes in peak intensities. The findings demonstrate Raman spectroscopy's dual potential: non-invasive diagnosis via elastin-related biomarkers and real-time efficacy evaluation of PDT through tyrosine-associated spectral changes, offering molecular specificity and dynamic monitoring without invasive procedures.