The Real-time Virtual Sonography (RVS) is a system to depict a CT/MR/US reconstructed image of the same slice as that of the ultrasound image in real time from a CT/MR/US volume data.

First of all, carry out positioning to agree the position of the ultrasound probe with the coordinate system of CT/MR/US data.
A method is prepared to start synchronization of the CT/MR/US image and real-time US image from the point where an ultrasound image agreed with one of CT/MR/US images is obtained, thus positioning can be performed smoothly.

According to movement of the probe, the ultrasound image and CT/MR/US image vary in real time. Both images of the same slice can be observed while comparing them displayed side by side. Also it has a function to save the observation screen of RVS as digital stationary image or cine image.

Depending on CT scan parameters (posture, aspiration, etc.), an error may occur in actual observation, so they may not agree perfectly.