It is shown elsewhere that the use of dovetails allows one part to slide along another accurately whereas a T-slot allows one part to be held against another accurately but only when bolted down onto it.
It does not seem possible to use a T-slot instead of a dovetail. But is it possible to use a dovetail instead of T-slot?
It is. An example of this is on the lathe made by Bunting.
http://www.lathes.co.uk/bunting/
The cross slide has several dovetail sockets on it running at right angles to the bed of the lathe. They are all very narrow. Instead of holding a long dovetail they are designed to take bolts with dovetail shaped heads. These are used to hold whatever tooling is required onto the cross slide.
One might ask “Whats the point?”. The point is that using dovetails like this does the same job as T-slots would do but the depth of metal needed to do the job is considerably less that would be needed to do the same job using T-slots.