25-10-2012, 10:45 AM
New Approaches in SPECT Breast Imaging
ABSTRACT
The primary objective of this research is to develop new techniques in single photon emission computed tomography
(SPECT) breast cancer imaging providing improved detection and characterization of early stage breast cancer. Projection data
were acquired by implementing a tiltable SPECT system on a breast and torso phantom. The data were reconstructed with both
an ordered subset expectation maximization (OSEM) algorithm and a filtered backprojection (FBP) algorithm with a ramp
filter. Results indicated that the OSEM values for SNR and contrast were higher at all tilt angles and may offer better shape
and uniform activity distribution of the breast compared to FBP images. Also, by using a tilted head SPECT system, the radius
of rotation decreases and the chest wall near the breast can be adequately imaged. This results in increased resolution and
sensitivity. A pinhole collimator is advantageous in imaging a breast due to its ability to get close to the breast and achieve
a small radius of rotation, though lead shielding was ineffective in eliminating background activity froa the myocardium and
liver. Combining a pinhole collimator with a tiltable head camera (T-22 SPECT) will hopefully provide us with improved
resolution and increased angular range.