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.