Figure 8

Four CT studies of the phantom with the embedded 3.15 cm diameter spherical target. Each image in the series represents a 3-mm transaxial reconstruction of helically acquired CT data. The first series (STATIC TARGET) depicts image acquisition with the target stationary, and serves as a reference and a surrogate of the true axial geometry of the imaged target. The second series depicts the same target scanned with a 1-s slice acquisition time and moving in 3D. The third and fourth series illustrate the effect of changing slice acquisition time from 1 s to 4 seconds (acquisitions in series 3) and also changing the initial motion-to-scan phase relationships from 0 to π(acquisitions in series 4).