THE QUANTITATION OF THE DYNAMIC IMAGE FEATURES

(II) THE QUANTITATIVE ASSESSMENTS OF ERRORS INTRODUCED ON FUNCTIONAL IMAGE

Abstract

We reported previously about the method of constructing functional images, which is based on the one compartment model expressed with X (t) =a+b.exp (-ct). In this report, various errors introduced on functional images have been assessed quantitatively. Generally, the magnitude of the parameter errors in the functional image depends on the following factors : (1) dose of RI-tracer, (2) conditions of data acquisition, (3) characteristics of the radioisotope imaging system, (4) method of the data processing technique when construct the functional images.
In our studies, the parameter errors resulting from fitting exponential function X (t) as a function of RI-tracer dose, without or with the nonuniformity correction and the dead time loss correction, the manner of determination of t =0, the amplitude ratio and the magnitude of the exponent of the function, are estimated experimentally and theoretically, under the fixed conditions of data acquisition.
The results indicates that it is important to define the method of determining the point of t = 0 and to adopt the method which the accuracy and the precision of fitting exponential functions are independent of the dose of RI-tracer and the characteristics of the observations.