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