Significant Anomalies In the scanner-reported values of CTDI vol for stationary table protocols are described, in which elevated values of CTDI vol over 300% higher than the actual dose to the phantom have been observed, and which are well beyond the typical accuracy expected of CTDI vol as a phantom dose. Observed clinical anomalies include a neck perfusion study and a high-resolution axial chest CT for which the scanner-reported CTDI vol over-estimated the actual weighted doses by 280% and by 340%, respectively, as calculated herein. Recognition of these types of CTDI vol outliers as incorrect is important to users of CT dose index tracking systems (e.g., ACR DIR); moreover, a solution to the problem is available (Dixon and Boone 2010, 2011; AAPM 2010) and easily implemented as shown in this chapter.