Nuclear medicine is a branch of medical imaging that uses small amounts of radioactive material to diagnose, determine the severity of, or treat a variety of diseases including:
- Many types of cancers
- Heart disease
- Gastrointestinal conditions
- Endocrine disease
- Neurological disorders
- Various abnormalities within the body
What is nuclear medicine?
With ordinary x-ray examinations, an image is made by passing x-rays through the patient's body. In contrast, nuclear medicine procedures use a radioactive material, called a radiopharmaceutical or radiotracer, which is injected into the bloodstream, swallowed or inhaled as a gas.
This radioactive material accumulates in the organ or area of your body being examined, where it gives off a small amount of energy in the form of gamma rays. Special cameras detect this energy, and with the help of a computer, create pictures offering details on both the structure and function of organs and tissues in your body.
Nuclear medicine involves injecting the patient with a radioactive substance. It uses cameras to capture the physiology from the patient. This can be done in a traditional gamma camera, like when you have a bone scan or looking at the thyroid, or by using a PET/CT, which is another form of nuclear medicine where physicians are able to look at cancer and try to monitor the response to therapy.
Using nuclear medicine for diagnostics
External detectors are used to capture the radiation emitted from the radiopharmaceutical as it moves through the body, and this is used to generate an image. Diagnosis is based on the way the body is seen to handle substances in the health state and disease state. The radionuclide used is usually bound to a specific complex (tracer) that is known to act in a particular way in the body. When disease is present, the tracer may be distributed or processed in a different way compared to when no disease is present. Increased physiological functions that may occur as a result of disease or injury usually results in an increased concentration of the tracer, which can often be detected as a “hot spot.” Sometimes, the disease process leads to exclusion of the tracer and a “cold spot” is detected instead.
Treating disease with nuclear medicine
A large variety of tracer complexes are used in nuclear medicine to visualize and treat the different organs, tissues and physiological systems in the body. Nuclear medicine imaging techniques are also organ- or tissue-specific. While a CT or MRI scan can be used to visualize the whole of the chest cavity or abdominal cavity, for example, nuclear imaging techniques are used to view specific organs such as the lungs, heart or brain.
Nuclear medicine studies can also be whole-body based, if the agent used targets specific cellular receptors or functions. The difference, again, in nuclear medicine is that the source of radiation is from the injection that we give the patient and the focus lies in primarily looking at physiology. Nuclear medicine imaging provides unique information that often cannot be obtained using other imaging procedures and offers the potential to identify disease in its earliest stages.
You can further discuss pros and cons of nuclear medicine with your doctor.