Figure 7.
The MAA method applied to a chest phantom with four pairs of bilateral pedicle screws in Study #2. (a) Spectral shift metric map qpoly (θ, ϕ), with a tilted semi-circular orbit marked in green satisfying the 5% of maximum-to-minimum range criterion. (b) Objective function Qpoly (ϕ) determined from (a). (c) Magnitude of blooming artifacts vs. tilt angle for four screws. (d) Magnitude of blooming artifact averaged over eight screws measured as a function of tilt angle. Artifact magnitude was found to minimize at the tilt angle predicted by MAA (and same trend as (b)). (e–f) Axial image (through the shaft of screws #2 (a and b) acquired at gantry tilt angles, ϕ = 0° (➂) and ϕ = −20° (➁).