title: The Changing Design of Positron Imaging Systems.
abstract: This is a time of rapid change in the evolution of clinical positron imaging systems, spurred by the wider availability of (18)F-fluorodeoxyglucose, continued increase in clinical research trials showing the clinical efficacy of PET in numerous cancers, coronary artery disease, and a variety of neurological disorders, recent successes in changing the FDA approval process for PET radiopharmaceuticals, and the recent decision of HCFA to reimburse for PET procedures. To adapt to this new environment for clinical positron imaging, a number of approaches are being taken to cut the cost of positron imaging systems while still maintaining the inherent sensitivity and quantitative advantages that relate to coincidence imaging. In this article, we present some of the newer developments in positron imaging systems, discuss some of the limitations with currently available "low-cost" systems, and point the way to some future developments that will rapidly result in improved systems for clinical positron imaging. It should be noted that PET scanners have gone through many generations of technology advancements. These advancements along with new detector materials, new image reconstruction algorithms that improve signal-to-noise, lower cost/higher performance computer technology, and the present infectious enthusiasm for new ideas are all converging to produce a highly competitive marketplace of new camera solutions for clinical positron imaging.