Comparison of scintimammography and dedicated emission mammotomography

Using a 16 cmtimes20 cm medium field of view CZT camera and a compressible breast phantom containing deformable lesions of various sizes and activity concentrations, a detailed comparison is made between 2D, planar scintimammography utilizing various degrees of breast compression and fully 3D, dedicated, uncompressed breast SPECT, or emission mammotomography. A 700 mL compressible anthropomorphic breast phantom attached to a chest plate was developed in order to compare 2D and 3D emission (or transmission) imaging of a breast containing small lesions in the same phantom, while providing physical attributes that mimic realistic imaging conditions including hindrances that could limit otherwise ideal imaging of an isolated breast phantom. Thin walled, tillable, deformable lesions from 40 to 500 microL volume suspended on narrow polyethylene tubing are used so that their shape would change with different degrees of breast compression and also to provide minimal lesion wall and support thicknesses. Experiments were performed with low noise, and lesion-to-background concentration ratios range from 3:1 to 12:1. Scintimammography is performed for equivalent times for compression thicknesses from 6 cm to 12 cm (fully uncompressed) using a single medio-lateral view, and mammotomography is performed for the uncompressed breast for vertical axis of rotation, simple tilted parallel beam, and a trajectory based on a 3-lobed sinusoid projected onto a hemisphere. Image quality, based on lesion SNRs and contrasts, as well as degree of sampled breast volume are evaluated. Dedicated mammotomography appears to be nearly twice as effective as planar scintimammography under these measurement conditions