Yes, just select "External File" as the destination.  That'll image to just a raw image.  However, there's a major drawback to this.  If you try to skip ahead, say to start imaging from the higher LBAs, it'll hang for a really really really long time while it zero fills up to that area.  So if you're trying to image a 1Tb drive from the back to the front, it'll hang until it's done writing 1Tb of zeros.
The other option is to just mount the task in DE, but that's a bit slow for scanning.
If you expect to do a lot of logical scanning afterward, it's probably best to use a physical drive as the destination rather than image files.