The feasibility of using a fully optical ECG monitoring system for safe, truly artifact-free cardiac MRI will be demonstrated. The "optrode" sensors measure the heart's electrical activity using light rather than electrical current. This represents a paradigm shift in monitoring technology. The photonic system enables safe, continuous ECG monitoring, while the MR scanner is turned on. It provides both artifact-free ECG signals and uncorrupted MR images. Because there are no electrical or electronic components in the magnet room, performance is optimized and there is no burn risk to patients. Phase I will develop, fabricate, and test the MR- compatible optrode system inside and outside the magnet. The results will be analyzed and compared with those of a commercial FDA-approved electrical-based MR-compatible system. Preliminary tests of the optrode demonstrated its ability to measure and transmit ECG signals as well as conventional electrode technology. The completely light-based system does not interfere with the RF, static & dynamic magnetic fields of the scanner. Phase III will optimize the design for a commercial system and initiate a partnership for Phase III marketing. PROPOSED COMMERCIAL APPLICATIONS: The optical sensor-based ECG monitor has applications both within and without the magnetic resonance chamber. In addition to cardiac MR, the ECG optrode may be used for ambulatory monitoring, anesthesia awareness monitoring, critical care, and emergency medicine. Because it does not involve skin preparation or the attachment of electrodes, it may be effectively used by emergency personnel in ambulances and medical flights, at accident sites, or at scenes of mass trauma. ECG recording may be accomplished rapidly by placing the optrodes on the patient's clothing.