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| Fig. 1: Normal Whole Body PET/CT Scan (Source: Wikimedia Commons) |
Nuclear medicine is a particular field of medicine that uses radioactive tracers (i.e. radiopharmaceuticals) to diagnose and treat disease or to assess a patient's various bodily functions. Radioactive tracers represent a diverse set of carrier molecules that are tightly bound to a radioactive atom. In each case, the radioactive tracer is administered to the patient in some capacity (i.e. intravenously) and then tracked carefully with specifically designed cameras. Single Photon Emission Computed Tomography or SPECT and Positron Emission Tomography or PET scans are two of the most common and most well known imaging techniques within the field. [1]
The use of radiopharmaceuticals can be traced all the way back to early 19th century. In 1911, Chemist George de Hevesy was working under Ernest Rutherford when he discovered that a radioactive substance is chemically inseparable from the element of which it is a part. This discovery led him to develop a novel chemical technique in which one could use a radioactive label to trace the behavior of that element. However, his experiments were limited to the use of natural radioactive elements such as lead, thorium, bismuth, and thallium. [2]
It wasn't until 1933 that Frederic and Irene Joliot-Curie and Enrico Fermi proved that you could produce radioactive isotopes from any element by bombarding it with particles. This was the first instance of creating artificial radioactivity. [3] This breakthrough paved the way for technologies in which chemical processes in the body are tracked with those very radioactive isotopes first produced over 80 years ago.
The development of nuclear medicine has led to an entire subset of extremely effective strategies in diagnosis and disease therapy. In fact, much of our current understanding and knowledge of metabolic and physiological processes in the body and mind are due to the radioactive tracer method. [2] Today, there are over 100 various nuclear medicine imaging procedures, and every organ can be imaged. These techniques allow for the treatment and diagnosis of: (1) neurological diseases, (2) cancer, (3) gastrointestinal diseases, (4) neurological diseases, (5) genitourinary diseases, (6) coronary artery disease, (7) bone diseases and trauma, (8) infections, (9) pulmonary diseases. [4]
The emerging advancements in nuclear medicine are vast and diverse. It is impossible to predict all the ways in which radiopharmaceuticals will improve diagnosis and treatment of disease, but I will attempt to outline a few exciting prospects for the future. Although nuclear imaging techniques have already been used to understand the underlying chemical processes of brain behavior; however, we have yet to use these strategies to understand the relationship between brain chemistry and behavior (i.e. eating disorders). In addition, nuclear medicine could be very useful in deepening our understanding of the metabolism and pharmacology of new drugs, an area that has only been partially explored with these techniques. [5]
Lastly, one of the most promising aspects of nuclear medicine is the emerging field of "personalized medicine." With a deeper understanding of both normal and pathological physiological processes and the mechanisms that belie disease, we can move towards a more accurate prediction of a patient's response to any given treatment. However, this process is slow and laborious. If we can use targeted radionuclide therapies to personalize treatment, we can accelerate the process of advancing patient care and ultimately move towards a world of specific and individualized medicine. [5]
© Grace Klaris. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] R. Chandra, Nuclear Medicine Physics: The Basics, 7th Ed. (Lippincott, Williams amd Wilkins, 2011).
[2] S. Carlson, "A Glance At The History Of Nuclear Medicine," Acta Oncologica 34, 1995 (1995).
[3] C. Bernardini and L. Bonolis. Enrico Fermi: His Work and Legacy (Springer, 2004).
[4] F. A. Mettler Jr., and Milton J. Guiberteau. Eds., Essentials of Nuclear Medicine Imaging (Saunders, 2006).
[5] Advancing Nuclear Medicine Through Innovation (National Academies Press, 2007).
