Modelling The Use Of Stationary, Rectangular Arrays Of X-Ray Emitters For Digital Breast Tomosynthesis

The recent development of compact, cold cathode X-ray emitters presents the opportunity to use multiple emitters arranged in an array to perform medical imaging from a stationary source. This study considers some of the potential advantages in their application to digital breast tomosynthesis and breast specimen imaging. It presents modelling results from simulated images based on a validated toolkit that models the X-ray source, breast tissue and X-ray image receptor performance. It also presents results from physical experiments using flat panel source geometries. Stationary sources eliminate focal spot motion blur which can improve the visualization of small features such as microcalcifications. A rectangular array of emitters can provide enhanced depth resolution compared to a linear sweep of emitter positions, as the projection images are obtained over a 'sweep' in two directions. Moreover, a rectangular array gives the opportunity to reduce the source to image distance (SID). Halving this distance reduces the required beam current by four times, which could significantly reduce the size, weight, and cost of an overall system, albeit with an increase in the angular width of the focal spot. Both the simulation and physical experiments show that depth resolution is considerably improved when using a rectangular array in comparison to a linear array. If a rectangular array is used at half the SID, and a quarter of the power, then this benefit is maintained, even though the focal spot has a larger angular width. This could provide enhanced imaging from lower-cost, smaller devices compared with conventional systems.