Optical and Spectral Observations on Cystine, Oxalate, and Apatite Renal Calculi

Abstract

ABSTRACT Micro-Raman and spatially resolved cathodoluminescence (CL) coupled to environmental electron microscope (ESEM) with energy dispersive spectrometry (EDS) are nondestructive techniques scarcely employed on renal calculi studies. This study used these techniques together with Electron Probe Micro-Analysis (EPMA), X-Ray diffraction (XRD), and Thermogravimetry (TG) to study a rare renal calculus with cystine and a common Ca-oxalate-apatite calculus in order to explore the applicability of these techniques. TG and XRD effectively determined the renal calculi, while ESEM and μ Raman provided useful information. The backscattering probe (BS) differentiates calculi with elements of dissimilar atomic masses such as P, S, and C. The authors inferred that the CL emission peaks at 325 (L-cystine-apatite) and 310 nm (Ca-oxalate) could be associated to oxygen hole center emission defects coupled with C—OH precursor bonds, while the CL spectral emission from the collagen proteins mask the hydroxyl-apatite spectra.