Fleming-Harrington Redistribution Wash-in Washout (FHRWW): The Platinum Standard for Nuclear Cardiology

The introduction of the Heisenberg Uncertainty principle and Nuclear Cardiology occurred simultaneously in 1925-1927. Thirty years later the Anger gamma camera would allow for a more sophisticated radioactive isotope counting to determine the presence or absence of disease. When employed with technetium-99m isotopes, ischemic heart disease can be inferred by differences in visual appearance of cardiac images. These gestalts of imaging results have been separated from the quantitative information recorded by the cameras computer. We investigated whether current camera and computer systems are sophisticated enough to quantify differences between images to be clinically relevant. Our study demonstrated that efforts to “sharpen” image appearance does so at a reduction in “accuracy”. Like Heisenberg, this work shows that one cannot know the exact location and the amount of activity simultaneously and that a decision must be made for accuracy over image sharpness if one is to truly quantify differences in isotope concentration between images. In 1927, Werner Heisenberg (Heisenberg 1927), published his “Uncertainty principle” which in brief states that it is impossible to simultaneously know both the position and momentum of an electron or any other particle with any degree of accuracy or “certainty.” To define the location of an electron required interaction with it. This interaction would result in movement of the electron and as a result, would move the electron. The best one could achieve is knowledge of where the electron was at the time of interaction. The first utilization of nuclear isotopes for medical imaging and evaluation of heart disease was conducted by Blumgart (1926) in February of 1925 when he injected himself with Radium C, which emits alpha and beta particles and gamma rays. As such, the Geiger counter chamber developed by Blumgart and Yens, could detect the passage of blood carrying the radium. The studies would first be published in 1926 (Blumgart 1926) and become known as “circulation time” and would dynamically define myocardial contractility by comparing changes in count activity over time. In 1957, Hal Anger (1957) demonstrated the first gamma camera designed to detect the emission of radioactive decay emanating from the patient. In essence, a modern Geiger counter which could be held some distance from the chest to measure isotope decay while present in cardiac tissue. The decay (scintillation) is detected by the camera after being absorbed by the camera crystal (usually sodium iodide) with the subsequent release of an electron from the sodium iodide, which is subsequently detected by a photomultiplier (PMT) tube as shown in Figure 6. These scintillations are tallied by the computer. These anger cameras have been used to image various regions of the body using radioactive isotopes which are known to localize to the tissues in question. For cardiac disease this has primarily included thallium-201 and technetium-99m.