patients with a previous history of non-small cell lung cancer, breast cancer, head and neck cancer (not thyroid cancer), ovarian cancer, esophageal cancer, or lymphoma (hodgkin's or non-hodgkin's) who have suspected recurrence on history and/or physical exam.

conventional imaging (e.g., x-ray, ultrasound, ct, mri, bone scan) is non-diagnostic.

age less than 18 years.

patient with established recurrence requiring staging of recurrent disease.

patients who, at the time of the initial evaluation, have already undergone pet/ct within 6 months prior to registration.

unable to lie supine for imaging with pet/ct.

pregnant or lactating female.

significant concurrent medical problems (e.g., uncontrolled diabetes, active cardiac disease, significant chronic obstructive pulmonary disease) making the patient unfit for further cancer therapy.

unable to give informed consent.