Yes, you certainly can use a single coil cartomizer in the DCT. Just be sure that you use an XL size carto (45mm). It also need not be flanged.
Smoktech made one of the first cartomizer tanks on the market. To promote their new cartomizers, which were the dual coils, they called the new tanks DCT (dual coil tanks) and included the dual coil carto. Somehow, many of the cartomizer tanks made by other manufacturers got called DCTs, too, and they included Smoktech's dual cartomizers, possibly because they were the longer 45mm
cartos. You know how much the Chinese copycat each other.
I wrote an article in one of my blogs about single coil vs dual coil cartomizers, which also includes a sample listing of vendors offering single coil pre-punched cartos for cartotanks, and a PBusardo video review of the Slap Yo Moma tank tool which I highly recommend to all cartotank users. Click the number link under my username/avatar pic.