ABSTRACT
Nuclear medicine is a medical specialty that uses radioactive substances for diagnosis and therapy. It is recognized as a powerful noninvasive modality capable of acquiring whole-body images and revealing changes in functional activity within tissues. Clinically, nuclear imaging procedures are used for diagnosis of many types of cancer, heart disease, neurological disorders, and other abnormalities [1-3]. The major advantages of nuclear imaging over other molecular imaging modalities are its exquisite detection sensitivity (femto-to picomolar range) and the ability to image without concerns over tissue penetration. Biomedical radioisotopes, used either alone or as part of a radiolabeled molecule, emit photons with energies ranging from 30 to 511 keV, which are detected by specialized camera systems. Based on the emission properties of the radioisotope and its detection method, nuclear imaging is classied as either positron emission tomography (PET) or single-photon emission computed tomography (SPECT). Both techniques involve the use of functional contrast agents to generate three-dimensional tomographic images used for diagnosis, treatment planning, and monitoring therapeutic response.
