Table 1.

Schedule of weekly and quarterly (on Siemens scanners at site B) or triannual (on GE scanners at site A) data collection on all nine CT scanner units. “✓” indicates that a measurement session was performed on that unit at that relative time period, while “-” indicates that no session was performed. Some cells are grouped to illustrate the data sampling used to calculate between-run (weekly) (cells grouped with dashed oval), between-run (triannual) (cells shaded gray), and between-scanner (cells grouped with solid oval) individual %CV values.