Single-photon emission computed tomography
Single-photon emission computed tomography (SPECT) tracers, such as123I-ioflupane (123I-FP-CIT) or123I-β-CIT, bind selectively to presynaptic dopamine
transporter (DAT) and can be used to measure the density of
nigrostriatal nerve terminals. The outcome of a meta-analysis suggested
that DAT-SPECT is useful in the diagnosis of early PD and in
differentiating PD from essential tremor and vascular parkinsonism
[46]. DAT-SPECT can also be utilized to follow disease progression
because striatal binding seems to correlate to different stages of
disease severity [49]. Importantly, 123I-β-CIT
SPECT-CT has shown translational potential as it can be used to
visualize dopaminergic degeneration in experimental animal models of PD
[50].123I-IBZM is an example of a radiotracer that
binds to dopamine D2 receptors and can be used for SPECT imaging of
postsynaptic striatal neurons [51].