Single-photon emission tomography (SPET),
using technetium-99m hexamethylpropylene amine
oxime, and positron emission tomography (PET), using
oxygen-15 butanol were compared in six healthy male
volunteers with regard to the mapping of resting state re-
gional cerebral blood flow (rCBF). A computerized
brain atlas was utilized for 3D regional analyses and
comparison of 64 selected and normalized volumes of
interest (VOIs). The normalized mean rCBF values in
SPET, as compared to PET, were higher in most of the
Brodmann areas in the frontal and parietal lobes (4.8%
and 8.7% respectively). The average differences were
small in the temporal (2.3%) and occipital (1.1%) lobes.
PET values were clearly higher in small VOIs like the
thalamus (12.3%), hippocampus (12.3%) and basal gan-
glia (9.9%). A resolution phantom study showed that the
in-plane SPET/PET system resolution was 11.0/7.5 mm.
In conclusion, SPET and PET data demonstrated a fairly
good agreement despite the superior spatial resolution of
PET. The differences between SPET and PET rCBF are
mainly due to physiological and physical factors, the da-
ta processing, normalization and co-registration meth-
ods. In order to further improve mapping of rCBF with
SPET it is imperative not only to improve the spatial res-
olution but also to apply accurate correction techniques
for scatter, attenuation and non-linear extraction.
