The method for the nondestructive determination of two-dimensional radial isotopic distributions of fission and activation products of irradiated fuel pins was improved. In this method the fuel pins are gamma-scanned diametrally at two or more angular orientations, and the diametral isotopic scans are unfolded into two-dimensional radial isotopic distributions. The computer code for processing the data was improved so that it calculates the individual diametral volume segments, the source self-attenuation factors, and the source intensity matrices. The two-dimensional source intensity matrices are presented as radial isotopic distributions, density plots, contour plots, and isometric projections. The new computer code improves the precision and reduces the analysis time as shown in the examination of more than 10 experimental fast-reactor fuel pins.