Cross-sectional study of kidney stones by laser-induced breakdown spectroscopy

Abstract

We performed laser-induced breakdown spectroscopy (LIBS) for the in situ quantitative estimation of elemental constituents distributed in different parts of kidney stones obtained directly from patients by surgery. We did this by focusing the laser light directly on the center, shell, and surface of the stones to find the spatial distribution of the elements inside the stone. The elements detected in the stones were calcium, magnesium, manganese, copper, iron, zinc, strontium, sodium, potassium, carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur, and chlorine (Cl), etc. We optimized the LIBS signals by varying the laser energy from 10 mJ to 40 mJ to obtain the best signal-to-background and signal-to-noise ratios. We estimated the quantities of different elements in the stones by drawing calibration curves, plotting graphs of the analyte signal versus the absolute concentration of the elements in standard samples. The detection limits of the calibration curves were discussed. The concentrations of the different elements were found to be widely different in different stones found in different age groups of patients. It was observed that stones containing higher amounts of copper also possessed higher amounts of zinc. In general, the concentrations of trace elements present in the kidney stones decreased as we moved from center to shell and surface. Our results also revealed that the concentrations of elements present in the stones increased with the age of the patients. The results obtained from the calibration curves were compared with results from inductively coupled plasma mass spectrometry (ICP-MS). We also used the intensity ratios of different elemental lines to find the spatial distribution of different elements inside the kidney stones.

Laser-induced breakdown spectroscopy is a reliable method for urinary stone analysis

“…[15,16] Chemical analysis is deemed obsolete, whereas physical analysis techniques such as XRD and IRS are currently recommended as the preferred techniques. [7,8] The use of LIBS in stone analysis has been described recently [12,13] but data supporting its use for this purpose are limited. In the present study, 65 urinary stones were comparatively assessed and analyzed using both XRD and LIBS.…”

“…Their results suggested that LIBS could be successfully used for elemental analysis of urinary stones. Singh et al [12] used LIBS to analyze five urinary stone samples and found that it can successfully identify urinary stone types. Anzano and Lasheras.…”

“…[28] Moreover, its inhibitory role in this process has not been clearly explained. Singh et al [12] used LIBS to analyze five urinary stone samples and found that Mg was detected in every part of all stones. We also found that Mg was detected in all urinary stones, supporting the findings of Singh et al [12] According to our results, the inhibitory effect of Mg on lithogenesis is unclear.…”

“…[12,13] However, there are insufficient data to support the routine use of LIBS for this purpose. To our knowledge, LIBS has not been compared with traditionally used and recommended techniques such as XRD or IRS.…”

2082 Strontium Substitution for Calcium in Lithogenesis

“…In support of this, strontium was present during early stone formation in nanobacteria studies 25 and more strontium is found in the kidney stones of older patients than in the kidney stones of younger patients. 30 Strontium has been demonstrated to interact in other hydroxyapatite biomineralization processes. Strontium in the form of strontium ranelate interacts with hydroxyapatite.…”