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Nuclear imaging is a form of medical imaging in which nuclear isotopes, also known as radionuclides, are used as part of the imaging study, with the goal of getting information about the patient's body which can be used in diagnosis, treatment, and monitoring of disease. There are a number of different types of nuclear imaging which can be used in a variety of ways to collect data about patients. Usually, the imaging study is ordered by a doctor and conducted by a nuclear imaging specialist, who may be a technician or a medical doctor, depending on the circumstances.
One of the oldest forms of nuclear imaging is also probably the most well known. The x-ray involves bombarding the body with electromagnetic radiation to form a picture of the internal structures. Computed tomography (CT) is a specialized form of x-ray imaging in which “slices” are taken to create a three-dimensional image of the structure of interest.
Other forms of nuclear imaging require the ingestion or injection of radionuclides, with the progress of the isotope through the body being followed with a camera which is capable of picking up the radiation signature. This type of nuclear imaging can be used to provide a real-time picture of the function in a specific area of the body, with doctors looking for things like signs that the isotope is leaking, being occluded by a blockage, or behaving in other ways which might suggest an abnormality.
In a positron emission tomography (PET) scan, for example, an isotope is injected into the body and followed as it moves through the patient. The isotope emits gamma rays which can be picked up by the imaging equipment, creating a map of the inside of the body and identifying areas of concern. Using data from a PET scan, doctors can look at things like the function of the intestinal tract or brain, identifying abnormalities which could indicate the presence of a medical problem.
The use of nuclear imaging has become much safer over the years, thanks to the development of sophisticated technology which reduces the overall exposure to radioactive isotopes. The isotopes used in nuclear imaging studies have very short half lives, and they are introduced to the body in small quantities so that they can be quickly flushed after the study is complete. Some risks are inherent in exposure to radiation, however, especially in the case of patients who require repeated studies, and doctors monitor their patients closely for signs that they are experiencing health problems related to radiation exposure.