An X-ray is a form of radiation, which is generated by special machines that permit imaging of internal body structures. Structures that are dense like bones appear white on the film and structures that contain air appear black. Muscle, fat and fluid will appear as various shades of gray. Since soft tissues, such as the kidneys, ureters, and bladder are not readily seen with x-ray, visualization is accomplished through the use of contrast agents which are injected directly into the organ or administered intravenously prior to or during imaging.

The test is performed in a radiology or urology department or in a health care provider's office by a technician under a physician's supervision. Depending on the type of test, the patient may be asked to stand, lie down, sit or any combination of the three. In some instances, a lead shielding device may also be used to partially cover the patient. This device can absorb some X-rays and shield areas of the body that are not be imaged. The patient may also be asked to remain still and to hold their breath for a few moments at different stages of the test.

Most simple X-rays take only a few minutes. However, more complex testing can last anywhere from 15 minutes to several hours.

A patient who is pregnant or may be pregnant should advise their physician prior to this test, as a fetus is susceptible to the risks of X-ray radiation.