A method of retrieving calculus in a renal pelvis of a living body involves positioning an enclosure in the renal pelvis, creating convection in the renal pelvis by introducing liquid into the renal pelvis from outside the living body to lift the calculus from a surface of the renal pelvis, retrieving the calculus in the renal pelvis by creating a vacuum in the enclosure while the enclosure is located in the renal pelvis so that the calculus are drawn into the enclosure, wherein the vacuum also draws the liquid into the enclosure, and withdrawing the enclosure from the renal pelvis while the calculus is in the enclosure.
