Rapid and Automated System Analyzes Kidney Stones

The system identifies the light spectrum of the examined sample by illuminating it with a laser, identifying the singular characteristic wave spectrum via the 1% of photons reflected back.

The researchers then use computer software to filter out the fluorescent background occurring during Raman spectroscopy. The results are then compared to a spectral database that contains data on the nine pure substances that make up 99% of urinary stones, as determined by examining nearly 160 samples; the results were confirmed by conventional infrared (IR) based analysis in a reference laboratory. Since the device employs relatively inexpensive optical components, and it can work on wet, unprepared samples, the time taken to prepare specimens is substantially reduced.

“The stones previously had to be dried and pulverized prior to analysis. Our system makes this unnecessary. Stone fragments collected during the surgical procedure do not need to be further processed. They can in principle be put directly into the Raman spectrometer for analysis,” explained IPM physician and researcher Arkadiusz Miernik, MD. “Currently there are a few specialized laboratories that can carry out this procedure using large-scale analytical equipment. A compact device suitable for use in a clinical setting and allowing immediate, post interventional automated analysis is not yet available.”

“We advise stone patients to drink plenty of fluids, increase physical activities and lose weight if necessary. Unfortunately this is only a general recommendation,” added Dr. Miernik. “Once the complete system is ready for clinical use, the physician will be able to examine stone samples directly after surgical intervention on his own, thus increasing the quality of patients’ care substantially.”

Kidney stones are often no larger than a grain of rice, yet some can grow to a diameter of several centimeters, causing blockage of the ureters. If it cannot be dissolved chemically, the kidney stone is treated using extracorporeal shock-wave therapy or minimally invasive endoscopic modalities. Many of these patients suffer from disease recurrence and need retreatment, but new stone formation might be reduced by 50% if individualized follow-up care and proper measures are offered to the patient regarding dietary habits or the use of particular medication strategies, based on stone composition.

Related Links:
Fraunhofer Institute for Physical Measurement Techniques 
University Medical Center Freiburg