An ultrasonic microscope is a useful tool for observing living tissue without chemical fixation or histochemical processing. Two-dimensional (2D) acoustic impedance microscopy developed in our previous study for living cell observation was employed to visualize intracellular changes. We proposed a brain tumor model by cocultivating rat glial cells and C6 gliomas to quantitatively analyze the effects of two types of anticancer drugs, cytochalasin B (CyB) and temozolomide (TMZ), when they were applied. We reported that CyB treatment (25 µg/ml, T = 90 min) significantly reduced the acoustic impedance of gliomas and has little effect on glial cells. Meanwhile, TMZ treatment (2 mg/ml, T = 90 min) impacted both cells equally, in which both cells’ acoustic impedances were decreased. As CyB targets the actin filament polymerization of the cells, we have concluded that the decrease in acoustic impedance was in fact due to actin filament depolymerization and the data can be quantitatively assessed for future studies in novel drug development.

To study the acoustic properties of a B-mode image, two ways of analysis methods were proposed in this report. The first method is the conversion of an acoustic impedance image into a B-mode image (Z to B). The time domain reflectometry theory and transmission line model were used as reference in the calculation. The second method is the direct a conversion of B-mode image into an acoustic impedance image (B to Z). The theoretical background of the second method is similar to that of the first method; however, the calculation is in the opposite direction. Significant scatter, refraction, and attenuation were assumed not to take place during the propagation of an ultrasonic wave. Hence, they were ignored in both calculations. In this study, rat cerebellar tissue and human cheek skin were used to determine the feasibility of the first and second methods respectively. Some good results are obtained and hence both methods showed their possible applications in the study of acoustic properties of B-mode images.