TU-E-217BCD-11: Evaluating the Performance of a Stationary Digital Breast Tomosynthesis System.

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. Hologic INC has provided the Hologic Selenia Dimensions used in the research. The project is supported by the National Cancer Institute under grant number U54CA119343 and R01CA134598 and the UNC University Cancer Research Fund. Dr. Xin Qian is supported by a fellowship from the Department of Defense under grant number BC087505.