CAC is pretty common, but I prefer Coronary CT Angiography, which is much more detailed CT of the heart and coronary arteries using IV contrast. It's a bit more radiation, but it shows soft plaque and arterial narrowing, which CAC does not.
They are both ECG gated scans of the heart otherwise so they're pretty much the same scan area and same scan duration, if you're hooked for a Coronary CT angiography you can easily get the CAC at the same time by doing a scan sweep before contrast administration (at the cost of 2 minutes of time and an extra dose of radiation)
Though the logistics surrounding contrast administration makes it a bit more fiddly with a slightly higher risk profile.