Each generation of CT scanner solved a specific bottleneck of the previous one — first translation, then rotation speed, then temporal resolution. Cardiac CT lives in the modern third-generation and dual-source designs.
Single detector with the source and detector translating forward and then rotating. Acquisition times were impractical for cardiac work.
Multiple X-ray beams translating in parallel — slightly reducing scan times.
Fan beam covering the entire patient width. Translation is eliminated in favor of pure rotation. This is the current standard.
Rotating X-ray source with a stationary ring of detectors.
No mechanical motion — 50 ms scan times — but the detector arrays are too narrow for general use.
Two X-ray sources at 90° to one another. Halves the required rotation time, substantially improving spatial and temporal resolution for cardiac imaging.