Stefano Rivetti PhD, Presenter: Research Consultant, FUJIFILM Holdings Corporation

Nico Lanconelli PhD, Abstract Co-Author: Nothing to Disclose

Virginia d'Andrea MD, Abstract Co-Author: Nothing to Disclose

Anna Sarnelli, Abstract Co-Author: Nothing to Disclose

Fabio Falcini, Abstract Co-Author: Nothing to Disclose

A new DBT unit (“Innovality” by Fujifilm) has recently been introduced in the market, characterized by two new implementations: first, linked to the detector’s design, is the TFT layout based on hexagonal geometry, instead the conventional square grid, and second, is the possibility to acquire images in two different geometries, respectively with a small (15°) and wide (40°) angle. We present the system’s characterization and a preliminary clinical trial performed to characterize the two DBT acquisition geometries.

This system is based on an aSe detector. The hexagonal TFT element used has an area similar to that achieved with a 68 um square pixel. The key issue is the higher signal sampling efficiency due to the hexagonal structure, compared to the square one: it permits, for obtaining similar spatial resolution, about 15% lower number of elements than those used with square sampling. The system’s characterization was obtained in terms of MTF, NNPS, DQE. DBT modality was characterized for both angles in terms of dose, artifact spread function (ASF) and resolution. The clinical study was performed in a side by side layout. Hundred patients (second level examination in screening population) was enrolled for the DBT acquisitions. For each patient one single projection was performed in both DBT geometries (ethics committee and informed consent). Images were scored, in terms of qualitatively parameters, by two blinded expert readers.  

System’s MTF is similar to that achieved with a 50 um aSe detector while the NPS is much similar to a 68 um detector: resulting peak DQE is around 80%. The two acquisition geometries shown significantly differences in terms of technical parameters: the small acquisition angle presents higher in plane resolution but worst ASF. The impact on the clinical images is a slightly preference for wide angle images when coupled with 2D projection otherwise a slightly preference for small angle. Wide angle projection is always preferred for high density breast.

The system shows interesting performance and the possibility to choose the acquisition geometries is an opportunity to fit at best the DBT exam for each patient.

The choice of the geometry can potentially help to optimize the DBT acquisition in function of the breast density and the clinical tasks.

Rivetti, S, Lanconelli, N, d'Andrea, V, Sarnelli, A, Falcini, F, Physical and Clinical Characterization of a New Breast Tomosynthesis (DBT) Unit.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013002.html