Inclusion Criteria:

Normal Volunteers

- Subject may be male or female and of any race / ethnicity

- Subject is > 18 years old at the time of investigational product administration

- Subject or subject's legally acceptable representative provides written informed
consent

- Subject is capable of complying with study procedures

- Subject is capable of communicating with study personnel

Cancer Subjects

- Subject may be male or female and of any race / ethnicity

- Subject is > 18 years old at the time of investigational product administration

- Subject or subject's legally acceptable representative provides written informed
consent

- Subject is capable of complying with study procedures

- Subject is capable of communicating with study personnel

- Subject 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. Carcinoma must be staged using the American Joint Committee
on Cancer (AJCC) staging criteria version 6. Adequate tumor must be amenable to
biopsy via outpatient methods

- According to the Karnofsky Performance Status Scale, the subject has a value of ≥
60% at time of screening

- Subject is scheduled for a clinical FDG PET scan either within 48 hours prior to
(with no intervention in between the two scans), or within 48 hours after the
investigational [F-18]HX4 PET scan

- Subject 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 limit of
normal

- creatinine within normal institutional limits

- BUN within normal institutional limits

Exclusion Criteria:

Normal Volunteers

- Subject is younger than 18 years old at the time of investigational product
administration

- Female subject is pregnant or nursing--Serum pregnancy test must be negative; test
must be completed within 24 hours of dosing or female subject must be either
surgically sterilized or post- menopausal, defined as at least one year without
menses as reported by the subject

- Subject is unable to remain still for duration of imaging procedure (~40 mins)

- Subject has previously received [F-18]HX4 at any time, or has been involved in an
investigative, radioactive research procedure within the past year

- Subject has any other condition or personal circumstance that, in the judgment of the
investigator, might interfere with the collection of complete good quality data

- Subject has a history of significant prescription or non-prescription drug, or
alcohol abuse, including but not limited to marijuana, cocaine, heroin or
derivatives.

Cancer Subjects

- Subject is younger than 18 years old at the time of investigational product
administration

- Female subject is pregnant or has a positive serum pregnancy test

- Subject is unable to remain still for duration of imaging procedure

- Subject has a history of significant renal disease

- Subject has previously received [F-18]HX4 at any time, or any other investigational
product in the past thirty days.

- Subject has been involved in an investigative, radioactive research procedure within
the past year

- Inadequate tumor sites or volume to allow for biopsy

- Subject 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

- Subject has a history of significant prescription or non-prescription drug, or
alcohol abuse, including but not limited to marijuana, cocaine, heroin or derivatives