Automatic registration of SPECT images as an alternative to immobilization in neuroactivation studies.

Subtraction of the two components (baseline and stimulation) of a neuroactivation study using 99Tcm HMPAO SPECT requires accurate registration of the two images. Immobilization of the subject during and between the two components of the study can prove difficult and degrades signal to noise ratio. The use of an automated image registration technique for registering the two components of the test can, even in the case where the subject is removed from the scanner, produce significantly better registration than immobilization.