A system for monitoring one or more temperatures at a vessel wall of a vessel of a patient includes an optical fiber, an optical read-out mechanism, and a therapeutic device. The optical fiber may be deployed along an extent of the vessel and may include one or more fiber Bragg grating (FBG) temperature sensors disposed at one or more corresponding sensor locations along a length of the optical fiber. The optical read-out mechanism may be optically coupled to the optical fiber, and it may be configured to transmit light into the optical fiber and detect light reflected from the one or more FBG temperature sensors. The detected light reflected from the one or more FBG temperature sensors may encode local temperatures at each of the one or more corresponding sensor locations. The therapeutic device may be configured for performing a therapeutic procedure to or through the vessel wall.