Fig. 5.

Example scaled, low-noise simulated projections at various indicated polar detector tilts and fixed 225-deg azimuthal angle. As the polar tilt increases, the detector begins to acquire direct views of the heart, liver, and torso, which contribute significantly to the detected events. The radiopaque patient bed minimizes contribution from the other organs near the edges of the field of view (FOV). However, it cannot prevent contamination from the anatomy directly behind the breast in the FOV. Note that the projections were generated by scaling component spectra according to their relative activity concentration, which results in nonproportional noise contributions from each organ. (a) No lesion, (b) 1-cm lesion, (c) 4-cm lesion.