Clinical Evaluation of the New Hypoxia Imaging Agent HX4

Inclusion Criteria: * Patient may be male or female and of any race / ethnicity * Patient is \> 18 years old at the time of investigational product administration * Patient or patient's legally acceptable representative provides written informed consent * Patient is capable of complying with study procedures * Patient is capable of communicating with study personnel * Patient must have histologically confirmed stage III, or IV squamous cell carcinoma of the head and neck whose primary origin was from the oral cavity, oropharynx, hypopharynx, or larynx. * According to the Karnofsky Performance Status Scale, the patient has a value of ≥ 60% at time of screening * Patient must have normal organ and renal function as defined: * total bilirubin within normal institutional limits * AST(SGOT)/ALT(SGPT) less than or equal to 2.5 x institutional upper limits of normal * creatinine within normal institutional limits * BUN within normal institutional limits * PT and PTT \< 2.0 x institutional upper limits of normal Exclusion Criteria: * Patient is younger than 18 years old at the time of investigational product administration * Female patient is pregnant or has a positive serum pregnancy test * Patient is unable to remain still for duration of imaging procedure * Patient has a history of significant renal disease * Patient has previously received \[F-18\]HX4 at any time, or any other investigational product in the past thirty days. * Patient has been involved in an investigative, radioactive research procedure within the past year * Inadequate tumor sites or volume to allow for biopsy * Patient has any other condition or personal circumstance that, in the judgment of the investigator, might interfere with the collection of complete and good quality data