What is SPECT?
SPECT stands for Single Photon Emission Computed Tomography.
Some representative cardiac SPECT projections in pseudocolor
are shown here (note they should be labeled "Projection" rather than
"Slice". Click on the image to stop the cine):
These images are obtained after the patient is injected with a radioactive
tracer (Thallium-201 in this case). A gamma camera detects the photons
being emitted from the patient, giving images like these. The different images
are from different angles (giving a projection at each angle). Counts are acquired at each angle for about
30 seconds. The radioactive tracer is designed to be taken up by normal
heart muscle, but not by abnormal (ischemic or infarcted) heart muscle.
Only the left ventricle can be seen in the images; the right ventricle is
too thin to be seen clearly. The lower bright spot is uptake from the liver.
The projections are combined to give one 3D static image of the heart.
A potentially more informative way of acquiring and using the information
is dynamic cardiac SPECT. In the dynamic case, an entire set of
projections
is acquired as often as every 5 seconds. Each set is reconstructed into
an image, giving a time-series of images of the changing radionuclide
distribution.
Currently, some of my research involves developing effective SPECT imaging methods for
the radionuclides Tc-99m-Teboroxime and F-18-Fluorodeoxyglucose (F-18 is
actually a positron emitter - see
511keV
for more information).
I obtained some of
my background from work at the
Nuclear Cardiology Department at Emory:Crawford Long Hospital.