The docs at our cancer center (both ENT/Surgeon and RO) seem to prefer the rigid, pistol-gripped scope with the 90 degree lens, rather than the flexible nasopharyngeal scope. Looking at films from each, it seems that the rigid one is a bit clearer, at least to my eye, and does have a larger field of view.

No anesthetic required, but you do need to remember to breathe to get past the gag reflex.