Efficient implementation of ultrasound waveform tomography using source encoding

Abstract

Ultrasound waveform tomography takes wave propagation effects into account during image reconstruction, and has the potential to produce accurate estimates of the sound speeds of small breast tumors. However, waveform tomography is computationally time-consuming for large datasets acquired using a synthetic-aperture ultrasound tomography system that consists of hundreds to thousands of transducer elements. We introduce a source encoding approach to ultrasound waveform tomography to significantly improve the computational efficiency. The method simultaneously simulates ultrasound waveforms emitted from multiple transducer elements. To distinguish the effect of different sources, we apply a random phase to each source. The random phase helps eliminate the unwanted cross interferences produced by different sources. This approach greatly reduces the computational time of ultrasound waveform tomography to one tenth of that for the original waveform tomography, and makes it feasible for ultrasound waveform tomography in clinical applications.