Multiwavelength Fluorescence and Diffuse Reflectance Spectroscopy for an In Situ Analysis of Kidney Stones

This study explores the use of diffuse reflectance spectroscopy (DRS) and multiwavelength fluorescence spectroscopy for real-time kidney stone identification during laser lithotripsy. Traditional methods are not suitable for in situ analysis, so the research focuses on optical techniques that can be integrated with lithotripsy fibers. Experiments were conducted ex vivo, using DRS and multiwavelength fluorescence spectroscopy (emission–excitation matrix (EEM)) to distinguish between 48 urinary stones of three types: urate, oxalate and hydroxyapatite, with infrared spectroscopy as a reference. A classification model was developed based on EEM and DRS data. Initial classification relying solely on EEM data achieved an f1-score of 87%, which increased to 92% when DRS data were included. The findings suggest that optical spectroscopy can effectively determine stone composition during laser lithotripsy, potentially enhancing surgical outcomes via the real-time automatic optimization of laser radiation parameters.