F3DT is a new technology for non-invasive imaging of the interior of an object. It is like the CT scan for imaging the interior of the human body, but instead of using radiative X-rays, it uses non-invasive mechanical waves (i.e., elastic waves in solids, sound waves in liquids). F3DT has a wide range of applications, including geophysical exploration for natural resources, seismic hazard assessment for earthquake insurance pricing, foundation engineering and tunnel construction in civil engineering, non-destructive testing (NDT) for evaluating potential defects in materials, components and structures in mechanical engineering, medical diagnosis of breast cancer and other conditions involving soft tissues, and sonar imaging for underwater object detection and characterization.