The long lifetime of Xe polarization and its strong solubility in blood combine to allow the use of polarized Xe for diagnostic imaging of parts of the human body. In conventional biological MRI, magnetic resonance signals are produced by weakly polarized proton spins found in biological tissues. Proton spins are weakly polarized by large magnetic fields. What is needed for higher contrast and better specificity in biological MRI and spectroscopy is a benign substance that can quickly enter tissues of interest, provide magnetic resonance signals that are sensitive to the local physical and chemical environment, and then leave the body. This proposals is for work on investigations of MRI enhanced by the use of optically polarized 129Xe or 3He to follow on promising suggestions that laser polarized Xe will provide just such a substance. The proposal is an SGER request for the production of polarized atoms followed by the study of invitro tissue samples and small mammal models. The study will be extended to humans after the SGER grant is ended.
