Cardiac nuclear imaging: principles, instrumentation and pitfalls.
The requirements for cardiac imaging with nuclear techniques are: (1) a radiolabeled tracer that is distributed in proportion to the function under investigation; (2) a collimator to allow photons arising only from specific areas of the heart to interact with the imaging device; (3) an imaging device to convert the gamma photon energy into an electrical signal that can be processed and displayed; and (4) a computer to record the information and permit quantification and optimal display of the data. One characteristic of nuclear imaging techniques is the requirement of averaging of a number of cardiac cycles to provide data for interpretation, whereas th information recorded with nuclear probes can be analyzed on a beat by beat basis. The data can be reviewed both visually and quantitatively. Semiautomatic methods of measuring ejection fraction, which correlate well with data from cardiac catheterization, have been in clinical use for several years. However, these techniques are not capable of correctly analyzing the data from all patients. Particular errors occur with gating, tracking the edge of the ventricle or in the selection of a background area, which may result in the calculation of an erroneous election fraction. In the future, short-lived radiopharmaceutical agents will result in a lower radiation burden to patients and higher quality studies in a shorter period of time, and tomographic techniques should provide new insights into the structure and function of the heart.
D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D011868:Radioisotopes; D011877:Radionuclide Imaging / Q000295:instrumentation*; D013667:Technetium; D013793:Thallium; D014055:Tomography, Emission-Computed
D011868:Radioisotopes; D013667:Technetium; D013793:Thallium