  Positron Emission Mammography imaging system (PEMi) is a nuclear medicine
diagnosis method dedicated for breast imaging. It provides a better resolution
in detection of millimeter-sized breast tumors than whole-body PET. To address
the requirement of semi-quantitative analysis with the radiotracer
concentration map of the breast, a new attenuation correction method based on
three-dimensional seeded region growing image segmentation (3DSRG-AC) solution
was developed. The method gives a 3D connected region as the segmentation
result instead of image slices. The continuously segmentation property makes
this new method free of activity variation of breast tissues. Threshold value
chosen is the key point for the segmentation process. The first valley of the
grey level histogram of the reconstruction image is set as the lower threshold,
which works fine in clinical application. Results show that attenuation
correction for PEMi improves the image quality and the quantitative accuracy of
radioactivity distribution determination. Attenuation correction also improves
the probabilities to detect small and early breast tumors.
