Imaging techniques play an important role in the management of the care of the patient who has suspected or known malignancy. Currently available tests have high sensitivity, but low specificity and high false-positive rates. For example, computed tomography scanning and magnetic resonance imaging provide sensitive cross sectional imaging and have improved the detection of small lesions without increasing etiologic specificity. Many masses cannot be further characterized with current imaging studies which may be a particular problem in the assessment of residual disease versus fibrosis. Often, results of these imaging studies create new problems and confusion that require additional tests and sometimes invasive approaches in order to obtain definite answers. Clearly, the oncologist and oncological surgeon need new screening tests with increased specificity without losing sensitivity for most common cancers, and new imaging techniques for staging and follow-up of very small volume tumors without sacrificing specificity. New nuclear medicine techniques such as positron emission tomography (PET) scan or immunoscintigraphy may provide a functional evaluation of a tumor for screening, staging, and follow-up. Initial results of immunoscintigraphy and PET imaging are very encouraging. They may in the future provide prognostic evaluation addition to anatomical assessment of tumor. Additionally, these new imaging studies survey the entire body and detect metastases at multiple sites (regional and distal) simultaneously. Therefore, we should determine the role of these imaging techniques in carefully controlled prospective trials.