The purpose of this trial is to determine what will be the optimal imaging protocol for Head and Neck Cancer patients after [F-18] HX4 injection. This study will provide guidance for future studies involving [F-18]HX4 in cancer patients.

Each consented patient will have a single administration of [F-18]HX4 and will immediately undergo one list mode PET/CT imaging session lasting 60 minutes followed by three additional list mode PET/CT acquisitions from 90 to 110 minutes, 150 to 170 minutes and 220 to 250 minutes after administration. The start times of the last three image acquisitions are permitted to be within ± 5 minutes. Venous blood samples will be collected throughout the initial scan sequence and at the time of each subsequent acquisition for calibration and metabolite-correction of the image-derived input function. On the day of administration (Visit 2) blood for clinical safety evaluations will be drawn pre- and post-dosing after all imaging is complete.

The pre-surgery [F-18]FDG PET/CT clinical scan performed prior to the [F-18]HX4 procedure, and the surgery at Visit 3 are standard of care for the consented patients.

Inclusion Criteria:

• Patient is >18 years and male or female of any race / ethnicity.
• Patient or patient's legally acceptable representative provides written inform consent Patient is willing and able to comply with protocol procedures.
• Patient has newly diagnosed histologically confirmed squamous cell carcinoma of the head and/or neck whose primary origin is from the oral cavity, oropharynx, hypopharynx, larynx or nasopharynx.
• Patient is scheduled to have or already has had a clinical [F-18]FDG PET/CT scan prior (recommended to be within 14 days prior) to the [F-18]HX4 PET/CT scan.
• Patient has a primary tumor ≥ 2.0 cm in longest axis measured by CT or MR; or lymph node ≥ 2.0 cm in shortest axis measured by CT or MR if primary tumor < 2 cm on CT or MR; CT may be part of required [F-18]FDG PET/CT scan or a separate pre-surgery CT scan.
• Patient is scheduled to undergo complete tumor resection within 7 days for his/her cancer care after the [F-18]HX4 PET/CT scan is performed.
• Patient has not had nor will have neoadjuvant treatment, including radiation and chemotherapy, prior to patient's planned tumor resection.

Exclusion Criteria:

• Female patient is pregnant or nursing.
• Patient is not capable of remaining still for duration of imaging procedure (~ 4 hours).
• Patient has undergone an investigative, radioactive research procedure within 7 days prior to study participation, or is scheduled to undergo such a procedure during the study participation period.
• Patient has chronic renal function failure or is on renal dialysis
• Patient has any other condition or personal circumstance that, in the judgment of the investigator, might interfere with the collection of complete data.