Abstract
Positron emission tomography (PET) measures quantitative values of physiological and biochemical functions by means of quantitative measurements of tracer concentrations in vivo and sophisticated tracer labeled by positron emitting radioisotopes (^<11>C, ^<13>N, ^<15>O, and ^<18>F). In order to achieve quantitative measurements as a clinical diagnostic tool we should remind several points to maintain data quality in routine PET study as follows: That is, cyclotron and radio-synthesis system should be managed properly, physical characteristics of PET device should be known to convert tracer concentration to physiological functions, maintenance of PET devices should be done properly, and circumstances of subject side should be kept to be comfortable to keep steady positron for rather long scan period.
