"The reduced radiation CT protocol (30 mAs) resulted in similar detection of renal stones 3.0 mm or larger compared with the standard radiation protocol (100 mAs) while reducing patient exposure by as much as 70%."

Effect of Reduced Radiation CT Protocols on the Detection of Renal Calculi
Jin DH et al
Radiology 2010; 255;100-107

"Detection of 2.0 mm stones is difficult, even with standard CT protocols by using 5 mm section reconstruction; this may lead to a significant overestimation of sensitivity in clinical studies where a conventional CT scan is used as a reference standard."

Effect of Reduced Radiation CT Protocols on the Detection of Renal Calculi
Jin DH et al
Radiology 2010; 255;100-107

"Decreasing the tube charge from 100 to 30 mAs resulted in similar detection of renal stones while reducing patient radiation exposure by as much as 70%."

Effect of Reduced Radiation CT Protocols on the Detection of Renal Calculi
Jin DH et al
Radiology 2010; 255;100-107