Processing of response functions obtained by radiotracer measurement. VII

The measurement errors of the system response to the delta-function are discussed for cases where 1) the time of the labelled compound entry in the investigated volume is not exactly known; 2) the entry is not instantaneous but lasts for a certain duration. The presented graphs demonstrate how strictly the conditions for the input function have to be observed; they show under which conditions the system response may be considered to be a response to the general input function rather than a function proportional to the residence time distribution. A brief survey of methods used in the solution to this so-called identification problem is presented. The individual methods are evaluated with regard to their suitability for the processing of data obtained by radiotracer measurements. For the solution to the identification problem, a slightly modified Dooge method using the Laguerre function is recommended. (author)