Evaluating the Performance of a Stationary Digital Breast Tomosynthesis System
A Tucker1*, E Gidcumb1, J Shan1, X Qian1, F Sprenger2, D Spronk2, Y Zhang3, D Kennedy3, T Farbizio3, C Ruth3, Z Jing3,J Lu1, O Zhou1, (1) University of North Carolina at Chapel Hill, Chapel Hill, NC, (2) Xinray Systems LLC, RTP, NC,(3) Hologic Inc, Bedford, MATU-E-217BCD-11 Tuesday 2:00:00 PM - 3:50:00 PM Room: 217BCD
Purpose: In conventional Digital Breast Tomosynthesis (DBT) systems a single x-ray source moves over a limited angle arc. This leads to motion blurring in the projection images associated with x-ray source motion and total scan times. We have developed a stationary DBT (s-DBT) system which forgoes a rotating source for an array of carbon nanotube (CNT) based x-ray sources. Here we report the results of evaluating the performance and the optimization of image acquisition parameters of the s-DBT system.
Methods: The s-DBT system consists of a linear source array with 31 x-ray generating focal spots distributed over a 30 degree angular span. The source array has been retrofitted onto a Hologic Selenia Dimensions DBT system. An American College of Radiology accreditation phantom was imaged to assess the quality of the reconstruction images in different configurations. A line wire phantom is used to measure the modulation transfer function (MTF).
Results: For the standard imaging protocol, the system resolution along the scanning direction is increased from 3.0 cycles/mm in DBT to 4.2 cycles/mm in s-DBT at a magnification factor of 1.08. The MTF did not have a noticeable change between different configurations, whereas in DBT the MTF can be degraded for larger angular spans due to faster x-ray source motion. The overall image quality factor is found to be best for the configuration with a large angular span and intermittent number of projection views.
Conclusions: We demonstrated successful construction and operation of the s-DBT system integrating a CNT x-ray source array with a Hologic DBT system. The spatial resolution of the s-DBT system is demonstrated to be substantially increased over the corresponding DBT system. It was found that a configuration with a large angular span, an intermittent number of projection views, and an even dose distribution resulted in the best overall image quality.