Medical applications of the radioisotope X-ray fluorescence analysis

The X-ray fluorescence, induced by small, sealed-off radioactive sources, can be applied as very sensitive method of analysis of trace elements in biological specimens. The preparation and technique for the analysis of small (0.1 to 0.5 ml) or larger (more than several milliters) volumes of liquid samples will be described, and the principal patss of the devices for analyzing only one element or a series of them are presented. The measuring time for typical analysis ranges between 10(2) and 10(4) seconds. For a simple X-ray fluorescence analysis the sensitivity of the method is varying between 10 ppm and 100 ppm when measuring during 100 seconds. A large number of applications of this method in the medical field is listed, concerning the analysis of trace elements naturally present in biological samples, and the analysis of elements employed as "stable tracers" in order to follow a dynamic process, or in order to label blood components, such as erythrocytes, leukocytes and platelets.