Joel Karp
University of Pennsylvania
Positron Emission Tomography (PET): Present and Future Technology
PET is a powerful imaging tool that is being used to study cancer, using a
variety of tracers to measure physiological processes including glucose
metabolism, cell proliferation, and hypoxia in tumor cells. As PET has grown in
the last several years, it has become clear that improved lesion detection and
quantification are critical goals for cancer studies. The performance of these
tasks will be described and related to the physical characteristics of PET
instruments. Data correction methods will be described as well as techniques for
fully 3D iterative reconstruction.
Although overall performance of the current generation of PET scanners has
significantly improved, there are limitations especially for heavy patients
where attenuation and scatter effects are increased. We have therefore begun
investigations of new scintillation detectors, scanner designs, and image
processing algorithms in order to overcome these limitations and further improve
performance. In particular, we are studying scanner designs that would
incorporate scintillators with improved energy and timing resolution. Improved
energy resolution helps to reduce scattered radiation, and improved timing
resolution makes it feasible to incorporate the time-of-flight information
between the two coincident gamma rays into the image reconstruction algorithm, a
technique that improves signal-to-noise. Results of recent experiments and
computer simulations will be shown to demonstrate these potential improvements.