123I-SCH 23982 is not suitable for dopamine D1 receptor imaging in vivo in the human brain.

: The tracer 123I-SCH 23982 was tested with regard to its ability to image dopamine D1 receptor in the human brain in vivo with single photon emission computed tomography (SPECT). The tracer did not reach equilibrium with regard to its binding to dopamine D1 receptors, presumably owing to fast metabolism to hydrophilic products and deiodination. It is concluded that 123I-SCH 23982 is not suitable for dopamine D1 receptor imaging with SPECT in the human brain.