CT scanning: a major source of radiation exposure.

CT scanning is a relatively high dose procedure that is becoming much more common worldwide. In the mid-1990s, CT scanning accounted for about 4% of procedures and about 40% of the collective dose in diagnostic radiology. With the advent of helical, fluoroscopic, and multi-slice techniques the dose per procedure has not diminished and the use of CT has increased even more.

US for detecting renal calculi with nonenhanced CT as a reference standard.

Purpose: To determine the sensitivity and specificity of ultrasonography (US) for detecting parenchymal and renal pelvis calculi and to establish the accuracy of US for determining the size and number of calculi.

Materials And Methods: A total of 123 US and computed tomographic (CT) examinations were compared retrospectively for the presence of renal calculi. The sensitivity of US was determined for individual calculi and at least one calculus per examination.