X-ray examination of the urinary tract, particularly the upper parts, i.e. the kidneys and the ureters. More rarely it involves the lower parts, i.e. bladder and urethra. Since X-ray contrast media are excreted close to 100% via the kidneys, pictures of the kidney parenchyma (=tissue) can be taken after 2-4 min. Pictures of the collecting system (= renal pelvis + ureters) are taken 5-10 min after this. To keep the contrast-containing urine from running down to the bladder, to image the ureters better the lower stomach may be compressed by inflating a rubber balloon under tight straps.