A guidewire providing imaging and light for photoactivation of therapeutic agents. Using optical fibers with Bragg gratings, electromagnetic waves are coupled to photoacoustic materials thereby providing acoustic energy for imaging tissues. The reflected acoustic waves can be sensed with photoreflective materials coupled to different optical fibers. Additional optical fibers allow photoactivated therapeutics to be activated in proximity to the imaged tissues. The photoactivated therapeutics may be administered intravenously or with a drug-delivery catheter.
