An Enhanced Multi-Frequency Distorted Born Iterative Method for Ultrasound Tomography Based on Fundamental Tone and Overtones

Conventional distorted born iterative method (DBIM) using single frequency has low resolution and is prone to creating images with high-contrast subjects. The authors propose a productive frequency combination method to better result in tomographic ultrasound imaging based on the multi-frequency technique. This study uses the natural mechanism of emitting oscillators' frequencies and uses these frequencies for imaging in iterations. They use a fundamental tone (i.e., the starting frequency f0) for the first iteration in DBIM, then consecutively uses its overtones for the next ones. The digital simulation scenarios are tested with other multi-frequency approaches to prove the method's feasibility. They performed 57 different simulation scenarios on the use of multi-frequency information for the DBIM method. As a result, the proposed method is for the smallest normalization error (RRE = 0.757). The proposed method's imaging time is not significantly longer than the way of using single frequency information.