Figure 8.
Study #3: Cadaver study with 6 pairs of implanted pedicle screws. (a) Spectral shift qpoly (θ, ϕ) metric map, showing reduction in spectral shift for tilt angles of ϕ ⩽ −10°. (b) The Qpoly (ϕ) objective computed as a function of C-arm gantry tilt. The minimum near ϕ = −10° suggests an optimal tilted orbit. Overlaid on the plot is a measurement of artifact magnitude (blooming) averaged over all 12 screws, in agreement with the MAA prediction. (c)–(e) Quasi-axial image slices (each slice oriented in plane with the screw shaft for purposes of visualization) at three vertebral levels. The optimal orbit as predicted by MAA was marked with ➀ in (a)–(e).