overview of some of the ways in which nuclear physics is being applied to address the nation’s challenges in health, homeland and national security, nuclear energy, and some of the innovations taking place in developing and exploiting new technologies arising from nuclear science.
Nuclear physics techniques have been revolutionary in medical diagnostics and cancer therapy. Of the 23 million nuclear medicine imaging and therapeutic procedures performed each year in the United States, typically 40-50 percent are for cardiac applications, while 25-40 percent are for cancer identification and therapy. In addition, nuclear medicine procedures are used to diagnose Alzheimer’s disease, treat hyperthyroidism, assess coronary artery disease, localize tumors, and diagnose pulmonary emboli.
The science of nuclear medicine, however, goes far beyond the radiopharmaceuticals used for imaging and treatment. Advances in the field are inevitably tied to basic research in nuclear physics at all levels. These advances include accelerators, detectors, understanding the interaction of radiation with matter, and creating complex statistical algorithms for identifying relevant data.
Over the past few decades, new nuclear imaging technologies have enhanced the effectiveness of health care and enabled physicians to diagnose different types of cancers, cardiovascular diseases, and neurological disorders in their early stages. Today there are over 100 nuclear imaging procedures available. These procedures have the additional advantage of being noninvasive alternatives to biopsy or surgery. Unlike other imaging procedures that are designed mainly to identify structure, nuclear medicine can also provide information about the function of virtually every major organ system within the body.
The most important modern advances in nuclear imaging are positron emission tomography (PET) and single-photon emission computed tomography (SPECT). PET, especially when coupled to X-ray computed tomography (CT) scans, has become a highly sensitive probe of abnormal functions, as described in detail in the PET highlight between Chapters 2 and 3.
18F-fluorodeoxyglucose (18F-FDG) is a radiopharmaceutical used in medical-imaging PET scans. This is a glucose analog that is absorbed by cells such as those in the brain and kidneys as well as cancer cells, which use high amounts of glucose. This procedure yields scans such as those displayed in Figure 3.1 and can be used for the study of organ functions and, in the case of cancer cells, for therapeutic applications. The 1.8-hour half-life t1/2 of fluorine-18 results in very high specific