Zongyi Gong BS, PhD, Presenter: Institutional research agreement, Hologic, Inc

Tushita Patel BS, Abstract Co-Author: Institutional research agreement, Hologic, Inc

Andrew Polemi, Abstract Co-Author: Institutional research agreement, Hologic, Inc

Brigid McDonald, Abstract Co-Author: Institutional research agreement, Hologic, Inc

Heather Renee Peppard MD, Abstract Co-Author: Consultant, Siemens AG Research Grant, Hologic, Inc

Mark Bennett Williams PhD, Abstract Co-Author: Institutional research agreement, Hologic, Inc.

Breast specific gamma imaging (BSGI) obtains a single 2-dimensional image of Tc-99m sestamibi uptake in the breast. Molecular breast tomosynthesis (MBT) maps the tracer distribution in 3 dimensions by acquiring multiple projections over a limited angular range. Here we compare the performance of the two technologies in terms of spatial resolution, lesion contrast and signal difference to noise ratio (SDNR) in phantom studies under conditions of clinically relevant sestamibi dose and imaging time.

The systems tested were a Dilon 6800 and a MBT prototype. Spatial resolution was measured using a phantom with evenly spaced point-like objects with varying heights. For lesion contrast and SDNR assessment, a box phantom containing spherical lesions at depths of 1.7 and 4.5 cm and diameters ranging from 4.9 to 9.8 mm was used. A single BSGI projection was acquired. Five MBT projections were acquired over ± 20 degrees. For both BSGI and MBT, the total scan count density was comparable to that in a typical 10 minute, 25 mCi human scan. The BSGI data were analyzed as both raw projections (noise-unregulated) and following Gaussian filtering (noise-regulated). The MBT data were reconstructed using an ML-EM algorithm (noise-unregulated) and a MAP-EM algorithm (noise-regulated).

Averaged over locations 1.5 cm to 7.5 cm below the top surface of the phantom the BSGI spatial resolution was 10.6 and 8.5 mm full width of half maximum (FWHM) with and without noise regulation respectively. The average resolution for MBT was 6.3 and 5.1 mm with and without regulation. Compared to BSGI, MBT improved lesion contrast by median factors of 2.1 and 1.7, and SDNR by median factors of 1.8 and 1.9 with and without regulation, respectively.

Under conditions of equal dose and imaging time, compared to BSGI MBT significantly improved lesion detection efficiency in terms of spatial resolution, contrast and SDNR.

MBT could substantially improve image quality in molecular breast cancer imaging.

Gong, Z, Patel, T, Polemi, A, McDonald, B, Peppard, H, Williams, M, Comparison of Breast Specific Gamma Imaging and Molecular Breast Tomosynthesis in Breast Cancer Detection: Evaluation in Phantoms.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14014627.html