Hypoxia, i.e. insufficient availability of oxygen within the tissue, is a more serious problem than realized in clinical routine work, although a large variety of theoretical and experimental data give clearly proven indications. During incidences and progress of many types of diseases hypoxia may enhance development and progress of the disease and, furthermore, decrease chances of efficient treatment of, e.g., tumors. Hypoxic tumor cells are up to three times more resistant towards radiation therapy than normoxic cells. With a diagnostic tool such as provided by hypoxia tracers suitable for...