Positron emission tomography (PET) becomes an interesting and promising diagnostic modality for hypoxia imaging in tumor tissue. Several tracers were developed for this purpose and Fluoromisonidazole (18FMISO) is the most extensively hypoxia tracer studied both in humans and animals (12-15). Previous results for imaging hypoxia using FMISO showed the regional distribution of tumor hypoxia, expressed as fractional hypoxic volume (16). However, its major disadvantages lie on its slow clearance kinetics and its high lipophilicity.