KUB refers to the radiography of the abdomen, which is the most routine examination of the urinary system. In the urological system, it is used to check for the presence of urinary stones and is usually performed in the supine or standing position. It is best to have an empty stomach before the examination to avoid the presence of stones due to excessive bowel movements or intestinal contents after eating. It is also advisable to defecate and empty the intestines before the examination, otherwise the fecal stones in the intestines may be mistaken for urinary stones, resulting in a false positive result. Abdominal radiography can also be indicated for perforation of intra-abdominal organs, etc. Usually in the upright position, if free gas is visible under the diaphragm, the diagnosis of perforation of the abdominal cavity with the presence of a hollow organ can also be confirmed. KUB can also be performed in conjunction with intravenous pyelogram to better identify obstruction or poor drainage of the urinary tract.