Not easily and it will probably get screwed up in the process anyway so I would go with Blender personally, but Milkshape and Shaper allow for DTS exporting as well. Any of the 3 will work.
You could technically use SketchUp, but it will take longer and you will either have to hope to God that your model doesn't get messed up, or learn to use Blender/Milkshape/Shaper anyway in order to fix your models.
Blender is free
Milkshape costs $20 - $30 (Somewhere around there, but there is a free 30-day trial)
Shaper costs money (don't know how much, check website, and there is a trial for this one as well)
As I said before, I would go with Blender, but you have to download and install the dts exporter plug-in as well as Python in order for Blender to work/export properly.
Edit:
There is another modeling program that I think can export DTS models, can't remember the name but I don't think you would want the program anyway, it costs around $1,200 (I can only remember that it is very expensive, considering that you're not professionally modeling for an actual game); It's for Pros
