A simple method for fabricating artificial kidney stones of different physical properties

A simple method for preparing artificial kidney stones with varying physical properties is described. BegoStone was prepared with a powder-to-water ratio ranging from 15:3 to 15:6. The acoustic properties of the phantoms were characterized using an ultrasound transmission technique, from which the corresponding mechanical properties were calculated based on elastic wave theory. The measured parameters for BegoStone phantoms of different water contents are: longitudinal wave speed (3,148–4,159 m/s), transverse wave speed (1,813–2,319 m/s), density (1,563–1,995 kg/m³), longitudinal acoustic impedance (4.92–8.30 kg/m² s), transverse acoustic impedance (2.83–4.63 kg/m² s), Young’s modulus (12.9–27.4 GPa), bulk modulus (8.6–20.2 GPa), and shear modulus (5.1–10.7 GPa), which cover the range of corresponding properties reported in natural kidney stones. In addition, diametral compression tests were carried out to determine tensile failure strength of the stone phantoms. BegoStone phantoms with varying water content at preparation have tensile failure strength from 6.9 to 16.3 MPa when tested dry and 3.2 to 7.1 MPa when tested in water-soaked condition. Overall, it is demonstrated that this new BegoStone preparation method can be used to fabricate artificial stones with physical properties matched with those of natural kidney stones of various chemical compositions.