SPECT imaging radionuclides

Nuclear imaging can be considered as a pure molecular imaging technique, since it can directly detect the molecules in which the radionuclides have been embedded. These compounds are called radiopharmaceuticals or radiotracers . Typical radionuclides for SPECT imaging are Tc, In, M, and Ga. Be-... 

TABLE 6.7-1. Radionuclides Suitable for Labeling Bioniolecules for SPECT Imaging of Tumors... 

In SPECT imaging, single photons are emitted from the radionuclide in all directions. Spatial location of the emissions is obtained by means of lead collimators. As in PET, the choice of the radioactive tracer for a study depends on the molecular process being examined. 

Although most SPECT imaging samples more or less static distribution of radionuclides, some SPECT systems can perform rapid sequential studies to mcmitor tracer clearance. An example of this is determination of regional cerebral blood fiom the clearance of Multiple 1-minute... 

Indium. In is a relevant radionuclide for SPECT imaging, with a half-life of 2.8 days and photon energies of 171 and 245 keV. Particular applications to dates are in tumour-targeted imaging. 

Radionuclides are primarily produced in cyclotrons or reactors, depending on the nuclear reaction required. Very short-lived radionuclides such as C, and are available only in institutions that have a cyclotron facility, and this limits their widespread use. Remote facilities rely on commercially available long- and medium-lived radionuclides In, Ga, etc.) and radionuclides produced by generators (e.g., " Tc). The most commonly used radionuclides in PET and SPECT imaging are listed in Table 1.1. A complete discussion about radionuclide production, labeling conditions, and recent progresses in radiochemistry can be found elsewhere (18-20). 

Like Tc and Ga, " in is another widely used radiometal in SPECT imaging procedures, "in is a cyclotron-produced radionuclide with a half-life of 2.83 days, which allows commercial distribution, "in decays by electron capture and emits two major gamma radiations including one at 171 keV, which is useful for detection by gamma cameras. 

B. Radionuclides Used in PET Imaging SPECT Imaging vs. PET Imaging Applications of PET and SPECT Molecular Imaging... 

Owing to the short half-lives of the radioactive isotopes involved (e.g., t n of carbon-ll=20min, ty-i of fluorine-18 = 110min), radiopharmaceuticals for PET (and related SPECT) imaging are typically produced on-site daily or at facilities in close proximity to the PET imaging center. Radiopharmaceutical production typically requires trained radiochemists, with specific and expensive facilities. Moreover, the short-lived radionuclides involved means that radiochemical reactions must be fast, efficient, and amenable to automation, and new techniques that facilitate radiopharmaceutical production and the ability to meet clinical demand for PET tracers are in demand. Solid-phase synthesis is an attractive synthetic technique to the radiochemist as it bears many of these desirable characteristics. Despite this, solid-phase organic radiosynthesis (SPOR) is a relatively new... 

SPECT imaging has lower attainable resolution and sensitivity then positron emission tomography (PET). The radionuclides that are used for SPECT imaging emit a single gamma ray photon (usually about... 

In SPECT, any radioisotope that emits y rays can be used. In contrast to annihilation photons, these y rays are emitted as single individual photons. Isotopes common in SPECT imaging include Tc, I, and I. These are the radionuclides most often used in nuclear medicine. 

PET and SPECT are both functional imaging methods that use externally administered radionuclide-labeled substances to image in vivo physiological processes in 3-D space 944... 

Indications for radionuclide imaging in these patients are detailed in current ACC/AHA guidelines [68] and ACCF/ASNC appropriateness criteria for SPECT myocardial perfusion imaging [69]. While a detailed discussion of these indications is beyond the purpose of this text, for patients with advanced... 

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