> I dont understand though, why you have to simultanously do this from all sides- have the ultrasound swim around with the patient? Takes out the comlexity?

One sensor can only see waves that reflect straight back. If you have more sensors (and fire them sequentially, like they do) you can detect pulses that are deflected, and measure the deflection angle. That gives you much better data

I get the impression that what they want is real-time scans, so you can see the organs moving and everything. But that would require a 3d arrangement of sensors, which is too expensive. Instead they have a 2d arrangement and move the sensor relative to the person in 1d. Having only one sensor and moving it in 2d would harm scanning speed and fidelity even more.