UWB Imaging Reconstruction Unit for Breast Cancer Detection

The Ultra-Wideband (UWB) imaging technique for breast cancer detection is based on the fact that cancerous cells have di erent dielectric characteristics than healthy tissues. When an UWB pulse in the microwave range strikes a cancerous region, the re ected signal is more intense than the back-scatter originating from the surrounding fat tissue. An UWB imaging system consists of transmitters, receivers and antennas for the RF part, and of a digital backend for processing the received signals. In this paper we focus on the Imaging Unit, which elaborates the acquired data and produces 2D or 3D maps of re ected energies. We show that one of the processing tasks, Beamforming, is the most timing-critical and cannot be executed in software by a standard microprocessor in a reasonable time. We thus propose a specialized hardware accelerator for it. We optimize and parallelize the software implementation for a more even comparison. We design the accelerator in VHDL and test it in an FPGA-based prototype. We also evaluate its performance when implemented on a CMOS 45 nm ASIC technology. The speed-up with respect to a software implementation depends on the degree of parallelism permitted by the target technology.