The virtual colonoscopy is not as intrusive as the real thing. Unfortuantely, it is not as accurate either:

The accuracy of virtual colonoscopy, which provides a computer-generated 3-D view of the colon, varies considerably, depending on the training and methods of the doctors performing it, researchers say.

The cancer-detecting procedure is less reliable than previously thought and not ready for widespread use, according to a study of 600 patients at nine major clinics.

It may not be ready yet, but virtual medicine has so much promise for the future. I, for one, am eagerly awaiting virtual dentistry!