Search results
Results From The WOW.Com Content Network
A radioactive tracer, radiotracer, or radioactive label is a synthetic derivative of a natural compound in which one or more atoms have been replaced by a radionuclide (a radioactive atom). By virtue of its radioactive decay , it can be used to explore the mechanism of chemical reactions by tracing the path that the radioisotope follows from ...
The patient swallows a radioisotope of iodine in the form of capsule or fluid, and the absorption (uptake) of this radiotracer by the thyroid is studied after 4–6 hours and after 24 hours with the aid of a scintillation counter. The dose is typically 0.15–0.37 MBq (4–10 μCi) of 131 I iodide, or 3.7–7.4 MBq (100–200 μCi) of 123 I ...
Positron emission tomography (PET) [1] is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption.
Diagnostic tests in nuclear medicine exploit the way that the body handles substances differently when there is disease or pathology present. The radionuclide introduced into the body is often chemically bound to a complex that acts characteristically within the body; this is commonly known as a tracer. In the presence of disease, a tracer will ...
Single-photon emission computed tomography (SPECT) is employed in theranostics, using gamma rays emitted by a radiotracer to generate three-dimensional images of the body. SPECT imaging involves the injection of a radiotracer that emits single photons, which are detected by a gamma camera rotating around the person undergoing imaging. [7]
The rainbow scale was used to code the PET images; radiotracer concentration is displayed from higher to lower as red > yellow > green > blue. [ 3 ] Before the use of functional magnetic resonance imaging (fMRI) became widespread, PET scanning was the preferred method of functional (as opposed to structural) brain imaging, and it still ...
The uptake of [18 F]FDG by tissues is a marker for the tissue uptake of glucose, which in turn is closely correlated with certain types of tissue metabolism. After [18 F]FDG is injected into a patient, a PET scanner can form two-dimensional or three-dimensional images of the distribution of [18 F]FDG within the body.
However, it is freely available to the bone surface for uptake because the equilibrium between erythrocytes and plasma is much faster than the capillary transit time. This is supported by studies reporting 100% single-passage extraction of whole-blood 18 F- ion by bone [ 13 ] and the rapid release of 18 F- ions from erythrocytes with a rate ...