Cardiac nuclear medicine is a special branch of nuclear science that uses radioactive substance called as radionuclide in the diagnosis of various diseases and abnormalities of the cardiac or heart muscles and tissues. In the nuclear imaging techniques, the radioisotopes or the radioactive tracers are mixed with other pharmaceutical compounds and chemicals to form radiopharmaceuticals. These radioisotopes after getting administered will localize at the cellular receptors of the specific organ and thus this technique is used to assess the disease process, extent of cellular function, and to study the physiological and anatomical features of cardiac tissues and structures supporting it. In certain cases cardiac nuclear medicine works both as a prophylactic as well as therapeutic measure. However cardiac nuclear medicine uses the destructive power of low ionizing radiations on various organs and tissues.
In cardiac nuclear medicine technique of imaging, radionuclides are infused or injected through our vein and external detectors of gamma cameras will form images by capturing radiations coming out of the tracers that are injected into the body. This distinguishes it from the traditional x-ray imaging where the external radiations are passed along the body.
Techniques used in Cardiac Nuclear Medicine
There are different techniques of using cardiac nuclear medicine. Scintigraphy is a method of creating images of two-dimensional structures. One of the most important facts about cardiac nuclear medicine is that it is not tissue specific in its function. It will show the physiological wellness of all structures associated with a specific organ. For example, if you want to study about the function of cardiac muscles, then by using cardiac nuclear diagnostic technique, you may be able to clearly know about the blood perfusion in the coronary blood vessels that supplies heart, cardiac output, ventricular work load etc. SPECT is a three dimensional tomography technique that make use of gamma cameras from several ankles and thus reconstruct the images in different planes. Positron emission tomography uses coincidence detective measures to make images.
There are gallium scans, indium scans and octreotide scans available in the nuclear medicine though thallium and often technetium are used commonly for the cardiac perfusion imaging.
Cardiac nuclear medicine will help us to follow the real disease process behind any disease process affecting heart. Nuclear medicines exploit the body’s ability to handle substances especially in the presence of any disease. The radio isotope introduced to ones body is chemically bounded to form a complex that acts specifically within the body. This radiopharmaceutical compound is commonly referred as a tracer. In presence of any illness the tracer will act differently and will get processed in a different way.
Different nuclear medicines work in different manners. Usually techinitium or tiny amounts of thallium infused in the body is absorbed by cardiac tissues except by certain diseased tissues. These areas are considered as soft spots in the imaging. But in case of certain other tracers, they will combine with the calcium which is released into the blood stream or to the tissues, in any emergencies like heart attacks thus forming hot spots in the image. These tracer complexes are thus analyzed for evaluating the organ functions.
Preparing the patient for cardiac nuclear medicine
Cardiac nuclear medicine therapy needs some patient preparations before they go for a radio isotope imaging. Prior to the scan the patient should be thoroughly checked for any allergies, or associated diseases. Blood pressure, pulse rate, blood profile, lipid profile, etc has to be examined and verified. Consent is also taken from the patient before the procedure saying that he is willing to take the test. Since the nuclear imaging will be a new experience to many patients, they should be given proper explanations regarding the procedures and also advice the aftercare process.
After the procedure, plenty of water has to be consumed by the patient to wash out the tracer and the punctured site has to be kept immovable for few hours. Vital signs has to be checked every fourth hourly and the patient should be strictly kept under observation as there are increased chances for dysrrhythmias or irregular heartbeats, chills and hypotension or decreased pressure.
Cardiac nuclear medicine can be considered as a part of molecular medicine where much emphasis is laid on the use of various imaging substances specific to a particular course of disease. This branch of medicine will aid us to probe in to the cellular level and improve the characterization, visualization and quantification of various biological or pathological phenomena that takes place in a particular organ.