We are using optical and mathematical insight to design a novel CAT-scan machine. Using spatial heterodyning principles, we exploit the sensor configuration and associated signal processing tools we have invented to recover a higher dimensional signal from lower dimensional sensor readings. In addition, we use a new generation of descattering methods from computational photography that can analyze and decompose direct component from global component. We have also built models to analyze light transport in scattering media.A sophisticated co-design of optical and digital processing will eliminate all moving parts and possibly allow us to use less harmful wavelengths. This will greatly simplify the design and allow us to build portable, always-on volumetric imaging devices. Beyond health screening and diagnostics, the ability to see inside our body will open up a range of applications in HCI, productivity and entertainment.