Taxiarchis Vasileios Sakellaris PhD, Presenter: Nothing to Disclose

Matthaios Koutalonis PhD, Abstract Co-Author: Nothing to Disclose

George Spyrou, Abstract Co-Author: Nothing to Disclose

Ana Pascoal PhD, MSc, Abstract Co-Author: Nothing to Disclose

Breast thickness affects mainly GMTF, GNEQ and GDQE especially for higher energies, whereas mean beam energy GNEQ, particularly for thin breasts and low glandularities, and GNNPS. Breast composition has relatively small effects on generalized metrics. GDQE degrades primarily due to breast thickness increase, and follow mean energy and glandularity increase.

The purpose of this work was to investigate the effects of breast thickness, breast composition and mean x-ray beam energy on the generalized (G) performance metrics (i.e. GMTF, GNNPS, GNEQ and GDQE) of an a-Se based digital mammography system.

The GMTF decreases approximately 2-3% (corresponding to a difference in the object frequency of 0.3 mm-1) as glandularity increases from 0% to 100%, for all breast thicknesses and beam energies. GMTF also decreases, as the mean energy increases from 18 to 25 keV, approximately 0.6% (0.1 mm-1) for a 2 cm thick breast, up to 4% (0.3-0.4 mm-1) for a 7 cm thickness, irrespective of the breast composition. As breast thickness increases from 2 to 7 cm, GMTF degrades by 24% (3-4 mm-1), with the decrease being slightly larger for higher energies. GNNPS is not affected by the glandularity, increases (~6-8%) with breast thickness and decreases (~31%) with beam energy. GNEQ and GDQE decrease as glandularity increases particularly for higher energies and thinner breasts. For a 2 cm thick breast at 25 keV, the decrease is approximately 5% whereas for 7 cm thickness at 18 keV is almost negligible. GNEQ and GDQE decrease by 45% as breast thickness increases from 2 to 7 cm, with its influence being slightly larger for higher energies. GNEQ increases 70-80% with energy a fact which is more evident for thinner breasts and lower glandularities. On the contrary, GDQE decreases around 10-11% with energy, for all breast thicknesses and glandularities, although this decrease tends to be smaller for thinner breasts with low glandularity.

A Monte Carlo model simulating digital mammography was used to study the effects of various breast thicknesses (2-7 cm), % glandularities (0%-100%) and mean beam energies (18-25 keV) on generalized metrics.

Sakellaris, T, Koutalonis, M, Spyrou, G, Pascoal, A, A Monte Carlo Study of the Influence of Breast Thickness, Breast Composition and Mean X-ray Beam Energy on the Generalized Performance Metrics of an a-Se Digital Mammography System.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12032763.html