ST. LOUISAn automated technique for coregistering MRI or CT
images with SPECT (single photo emission computed tomography) images
has the potential to improve the accuracy of prostate cancer staging,
according to research presented at the Society of Nuclear Medicine 47th
Zhenghong Lee, PhD, D. Bruce Sodee, MD, and their colleagues at
University Hospitals of Cleveland/Case Western Reserve University
used sophisticated new software to automatically coregister results
with SPECT imaging of ProstaScint (a monoclonal antibody labeled with
indium-111) and MRI in prostate cancer patients.
The resulting image shows the site of SPECT metabolic activity
superimposed on the same MRI-defined anatomic slice. The researchers
have also used the technique to coregister SPECT and CT prostate
The software maximizes Mutual Information, or relative entropy
between the two volumes, to calculate the optimal alignment of the
SPECT/ProstaScint and MRI images.
Virtual 3D Presentation
Data from this fused image is presented in virtually
three dimensions, or virtual 3D. The result, Dr. Sodee
said, is a significantly clearer image of the tumors size
and exact location.
The 3D virtual software will also have applications in coregistering
PET (positron emission tomography) images of metabolic cancer
activity with anatomic CT or MRI correlation, Dr. Lee said.