1. An intensity modulated radiation therapy treatment plan optimization system, comprising: a user interface configured to receive an input from a user; a non-transitory memory module configured to store an IMRT treatment plan data set; a display configured to display information to the user; and an optimizer programmed to: optimize the IMRT plan according to initial plan specified settings to create optimized dose distributions in a beam's eye view; generate dose gradient maps from the optimized dose distributions in the beam's eye view; receive specified dose gradients and specified sub-regions from the user through the user interface; and generate new dose gradient maps from the received specified dose gradients and the specified sub-regions.