Spinning shield is a thought people have had but it doesn't work very well in practice (for gamma imaging). Usually you want to avoid anything that blocks gammas as much as possible because you need every one you can get. I wanted to try spinning one of the scintillator logs we used, which is more or less the same idea, but it isn't practical either for a bunch of reasons.

Gammas tend to act more like particles in the detector. They don't stop all at once, they tend interact multiple times and deposit their energy in multiple places along a line via a ton of different physical interactions. My description was simplifying and conflating things a bit, you can look up optically segmented detectors, as well as Compton scatter cameras if you want a better answer. There are other imaging approaches, too.