ABSTRACT
Radio-tracer techniques have gained acceptance in the medical field because of the convenience with which photon-emitting tracers can be identified and quantitated by relatively untrained personnel. This chapter presents fluorescent excitation analysis (FEA) of stable tracers can provide the convenience of radio-tracer technology while avoiding the problems. The main disadvantage with FEA is its relative insensitivity: while nanogram to picogram amounts of radioactive tracers can be readily quantitated, presently it is difficult to do the same with unprepared samples that contain less than a microgram of stable tracer. The concept behind the equipment developed for medical work is the ability to accurately quantitate tracer concentrations in unprepared biological liquids and tissues. Since the tracer signal may represent less than 0.1% of all detected events, high resolution detectors must be used in FEA to separate the characteristic X-rays from other photons. An important complement to a detector system is its preamplifier and amplifier.
