In this paper, a new treatment or method has been presented to calculate the parameters of the etched track and its shape development after irradiating polyallyldiglycol carbonate (PADC) detector CR-39 by alpha particles using direct measurement of the track opening diameters. The method is based on a concept that the track diameter growth rate (VD) and the track etch rate (VT) are not constants with the progressing of the etching process. Some of the equations used in the case of VD to be a constant have been modified as a function of etching time to be more suitable for the case. Certain boundary conditions have been extracted from previous works based on the measurement of the track lengths directly from the track’s images, to use them in the equations that were applied to figure out the track parameters in the present work. A CR-39 detector was irradiated with alpha particles having energies of 1.53 MeV, 2.35 MeV, 3.06 MeV, 3.80 MeV and 4.44 MeV under normal incidence using 1 μCi 241Am source of 5.485 MeV. The irradiated detectors were etched chemically with an aqueous 6.25 N solution of NaOH at 70°C. The track parameters and the profile development, as well as the V(R’) function, were determined. The results obtained by this method using the track diameters information showed a good agreement with previous works that used the direct measurement of the track lengths.