This isprobably due to the relatively small fraction of the tumor where thetracer specifically binds compared to the nonhypoxic tumor volume.CAIX– MOC1.3D5 tumors sometimes show radiotraceruptake in the tumor rim, which is, based on the IHC analyses, mostlikely attributed to uptake in the well-perfused stroma and thus consideredas nonspecific binding. The gene discussed is CA9; the disease is neoplasm.