Visual Sonics Vevo-660 has interchangeable transducers with frequencies of 20, 30, 40, and 50 MHz. It is equipped with a heated animal stage with EKG and temperature monitoring. These systems are installed with research software to customize scanning and data acquisition. This instrument has been used not only to determine biological changes in mice such as spontaneous tumor growth or the presence of embryos, but also to visualize the physiological changes using contrast enhanced ultrasound.