Giga-Hertz ultrasonic microscopy: Getting over the obscurity- A short review on the biomedical applications

Scanning acoustic microscopy in the gigahertz regime (GHz-SAM) has long been a versatile and complementary micro and nanoscopic imaging and analysis tool. Nevertheless, it remained obscured to some extent, compared to its counterparts, such as atomic force microscopy (AFM), despite its unique capability of subsurface analysis. Some current research in our lab at Georgia Tech Lorraine is devoted to the use of the subsurface imaging of GHz-SAM in biological tissues, which has been restricted, mostly, to very stiff materials, in terms of acousto-mechanical impedance, such as metals.The feasibility, degrees of complexity, the different techniques, and future fates of (GHz-SAM) are discussed with particular focus on those most used in the biological applications, such as the combined phase and magnitude contrasts acoustic microscopy.This paper gives a general overview of SAM, the peculiarities of GHz-SAM with emphasis on the restrictions that led to the semi-obscurity of GHz-SAM so far, and reveals some recent research developments in this field in our laboratory. Keywords: GHz-SAM, Biomedical, Quantitative acoustic microscopy, Phase contrast, V(d), V(z)