The most common mode of performing computed tomography (CT) examinations is helical scanning employing tube current modulation technique. Papers featuring organ dose computations rarely apply the currently accepted organ risk factors to compute overall risk. Some commercial dose-tracking software include an organ-dose computation for each patient; for example, by matching the patient’s body habitus to a particular humanoid phantom on which Monte Carlo calculations of organ dose have been made. The various CT manufacturers will be responsible for the methodology and validation of the computation of water-equivalent diameter d, and thence Size-specific dose estimates. A reduction in dose increases the noise in CT scanning, and thus reduces low-contrast detectability; therefore, in the push to reduce CT dose, one runs the risk of making the scan “non-diagnostic” and of no immediate benefit to the patient, at the cost of a trivial reduction of future cancer risk to the patient.