I guess it'd be a good and bad thing dependant on the person, and an excellent tool in prosecution cases. If that does become possible, I think the next step would be viewing images of a persons dreams transmitted to a monitor. I saw it on some Sci-Fi film or TV show years ago.
There's probably been more than one Sci-fi film or TV show that has shown a person's dream being taped, but, the first time I can remember seeing this, is--I believe--"Futureworld." And ever since, I've always been intrigued by the idea of this some day happening, as I've had a number of dreams I've like to have been taped for later viewing.
Not a brain scan, but another Sci-fi idea is seeing what a dead person last saw by taking a picture of the retina of the eye, which supposedly retained an image of what the person last saw. Again, I imagine this idea has come up in several Sci-fi films and TV shows, but I first remember seeing it is in "The Invisible Ray" w/ Boris Karloff and Bela Lugosi.
