An Exploratory, Open Label, Single Center Study of [F-18]HX4

\[F-18\]HX4 is being developed as a diagnostic radiopharmaceutical for PET imaging. This trial is looking at the safety of \[F-18\]HX4. The Sponsor is seeking to determine if \[F-18\]HX4 may serve as a clinically useful hypoxia marker in diagnostic imaging, allowing the rational application of hypoxia related therapies to those patients most likely to benefit from them. Tumor hypoxia, a situation where tumor cells have been deprived of oxygen, caused cancer cells to become more resistant to the effects of radiotherapy and chemotherapy. A non-invasive study characterizing tumor hypoxia would facilitate the development of targeted therapies. The population to be studied consists of a total of ten (10) adult subjects, including, four normal volunteers and six cancer subjects, the latter with a confirmed diagnosis of head and neck cancer, as defined by the protocol eligibility criteria. The objectives of this exploratory study are to: * Gain information on bio-distribution of \[F-18\]HX4, and to evaluate the PET images of \[F-18\]HX4 for resolution, signal to background ratio for both intermediate levels of oxygenation, and at extreme levels hypoxia * Use this eIND in order to obtain the necessary information to file an IND application with the FDA. The information collected under this exploratory study will not be used for diagnostic purposes, to assess the subject's response to therapy, or for clinical management of the subject. * Begin collection of baseline imaging data * Collect \[F-18\]HX4 metabolism data * Gain information to improve study design and the conduct of future trials This investigation will be conducted as an exploratory, open-label, non-randomized, uncontrolled, single center, safety study. The trial is expected to begin subject enrollment in early January 2008 and end subject participation in June 2008. The duration of an individual subject's participation includes a screening visit, followed by participation in the actual study starting wi