Basics of nuclear imaging 159
In recent years there are new SPECT cameras on the mar ket which a
re
stationary and no rotation is re quired. The imaging done by these cameras
is focused on a specific organ (heart or bra in) in pre-clinical imaging [7] or
clinical imaging [15, 28, 37, 98].
5.3.4 POSITRON EMISSION TOMOGRAPHY (PET)
The goal of PET imaging is to determine distribution of radionuclides that
emit positrons which subsequently annihilate producing 511 keV photons.
Photons are detected by a large number of detector elements that surround
the patient. These detector elements form typically a ring around the scanned
object. The diameters of PET cameras vary depending on the application and
for clinical scanners they are about 80 cm.
Positron (e
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