Dr. Lector is Chuckie's pediatrician seen in the episode The Shot. He is portrayed as an elderly man, although he seems to be somewhat friendly. Chuckie, however, sees him as evil, because of his fear of him after he gives him a booster shot. His name is possibly a spoof of Dr. Hannibal Lector from Silence of the Lambs.
You can find Dr. Lector gallery here.