These various embodiments serve to facilitate improving the accuracy of a computed tomography (CT) process. This can comprise operably coupling at least one calibration phantom to a CT scan table and then, during a CT scan of an object that is disposed on the scan table, also gathering calibration information using that calibration phantom(s). By one approach, this calibration phantom can comprise one or more annular-shaped members. When using a plurality of annular-shaped members, at least some of the annular-shaped members can be disposed concentrically with one another. By one approach, in lieu of the foregoing or in combination therewith, this calibration phantom can comprise one or more pins and/or spherically-shaped members (and/or other shapes of geometric interest). If desired, such spherically-shaped members can be combined with the aforementioned pins.