Improved signal processing to detect cancer by ultrasonic molecular imaging of targeted nanoparticles.

In several investigations of molecular imaging of angiogenic neovasculature using a targeted contrast agent, Renyi entropy [I(f)(r)] and a limiting form of Renyi entropy (I(f,infinity)) exhibited significantly more sensitivity to subtle changes in scattering architecture than energy-based methods. Many of these studies required the fitting of a cubic spline to backscattered waveforms prior to calculation of entropy [either I(f)(r) or I(f,infinity)]. In this study, it is shown that the robustness of I(f,infinity) may be improved by using a smoothing spline. Results are presented showing the impact of different smoothing parameters. In addition, if smoothing is preceded by low-pass filtering of the waveforms, further improvements may be obtained. (C) 2011 Acoustical Society of America. [DOI: 10.1121/1.3578459]