Single Photon Emission Tomography SPET

In computer tomography (CT) with radionuclides, one or several radiation detectors, a computer and a display are used. The detector array is moved in relation to the patient, and the variations in counting rates with the absorbancies of the radiation in the body as a function of the geometry are processed by the software of the computer to give an image on the screen. This procedure is repeated in subsequent sections (slices) of the body, thus providing a three-dimensional picture. The resolution of the scan is of the order of 1 mm. The method is similar to that used in X-ray CT, but in the latter both the radiation source and the detector array can be moved in relation to the patient. 

The application of compounds labelled with suitable radionuclides as radiation sources makes it possible to measure the incorporation and discharge of these substances in certain organs of the body, thus providing information about the metabolism and the function of organs of interest. In this way, malfunction and disorder can be detected at very early stages. 

Radionuclides applied for SPET should preferably decay by emission of a single y-ray photon, and the best resolution is obtained at low y energies. 

Single photon emission tomography (SPET) is primarily used for cardiovascular and brain imaging. For example, brain tumours can be located after intravenous injection of Na Tc04, because such tumours exhibit high affinity and slow release 

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Serotonin (5-HT)-tenninal autoreceptor antagonists, 41 (2003) 129 Single photon emission tomography (SPET), 38 (2001) 189... 

Pilowsky LS, Busatto GF, Taylor M, et al. Dopamine D2 receptor occupancy in vivo by the novel atypical antipsychotic olanzapine-a 123IBZM single photon emission tomography (SPET) study. Psychopharmacology 1996 124 148-153. 

Nowadays, nuclear medicine has become an indispensible section of medical science, and the production of radionuclides and labelled compounds for application in nuclear medicine is an important branch of nuclear and radiochemistry. The development of radionuclide generators made short-lived radionuclides available at any time for medical application. New imaging devices, such as single photon emission tomography (SPET) and positron emission tomography (PET) made it possible to study local biochemical reactions and their kinetics in the living human body. 

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