Unity as a VST's interface?

Hi, I would like to use Unity to build a VDT. Such as Native Instruments's Massive VST. The problem is, a VST's final form is a DLL and I think a VST project needs to be compiled to a DLL from code by some special ways. The real question is, could I use Unity only as a part of a bigger project? To do only the interface? I would like yo do a program where Unity would call some methods and functions, and being able to be called by some methods and functions of the program. I like Unity and would like to include it in such a project, rather than using other 3D libraries to my program.