[Mineralogical and radiological studies in children with urolithiasis].

The x-ray investigations are performed in every case of urolithiasis. The basic ones are plain films of abdomen, urography and voiding cystourethrography. These investigations do not establish the type of lithiasis, particularly in cases of mixed stones. A visualization of concrements on a plain film depends on the absorption coefficient of x-rays. There is a close connection between radiological morphology and chemical composition as well as structure of concrements. A precise determination of phase composition of stones and their structure is possible only in the indirect investigations, i.e. after concrements' extirpation. X-ray structural methods, infrared spectrometric method, thermal and optical ones in polarization light belong to indirect inquires. The diffractograms are a consequence of x-ray structural analysis. A comparison of them with specimens allows for identification of every crystallic substance. The principle of the infrared spectrometry is a selective absorption of infrared rays in substances of different chemical structures. A comparison of infrared absorption spectrum with specimens allows for identification of some substances. An advantage of this method is its high sensibility and the possibility to perform on a small quantity of substratum (1 mg). An optical method facilitates a microscopic observation of a thin plate of stone (0,02 mm) in the polarization passing light appropriate to qualify the basic optical properties of minerals. It is possible to see the inside of concrements in the relatively big magnification without destruction of its primary structure. The recognition of the main and subordinate components in renal stones is possible through the use of at least several very precise methods, from which x-ray structural analysis, optical and infrared absorption are of main importance.