Single photon emission computed tomography in cancer imaging.

Although structural imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) have revolutionized the noninvasive assessment of visceral anatomy, significant difficulties remain in the diagnosis and surveillance of cancer. Differences in the metabolism and biochemistry of tumors, compared with normal tissues, are known to precede and are responsible for the changes in structural anatomy imaged by CT or MRI. Recent advances in nuclear imaging techniques utilizing single photon emission computed tomography (SPECT) provide improved 3D spatial resolution, compared with previous planar 2D nuclear imaging techniques. New techniques are also able to characterize differences in the biochemistry and functional metabolism of neoplastic tissue, compared with normal tissue. These new technologies offer potent advantages over previous nuclear imaging and structural imaging techniques, not only in the diagnosis of cancer but also as possible tools for monitoring and predicting the effects of therapy on cancer metabolism.