Purpose: In this study, the team modeled the biodistribution and the efficiency of two 99m-technetium diethylene triamine penta acetate (99mTc-DTPA) based radiopharmaceuticals. Methods: The first radiopharmaceutical (DTPA-CNESTEN) is developed at the laboratories of the radiopharmaceutical production unit of the National Center for Nuclear Energy, Sciences and Technologies (CNESTEN-Morocco), and the second one is the commercial DTPA (DTPA-ref). Freeze-dried kits were successfully radiolabeled (radiochemical purity >95%) with the 99m Tc. Then drugs were injected to male BALB/c mice. In each 2 min, 5 min, 15 min, 1 h and 2 h time points after injections we evaluate tissue’s distributions characteristics. At the end, an automatic modeling of the data were recorded from thyroid, blood and urinary excretion kinetics and biodistribution in mice using both DTPA kits. The study aimed to extract the parameters of the function used to fit the recorded data. Results and Conclusion: the team concluded that the biodistribution of 99mTc-DTPA can be modeled using a combination of two exponential parts. Moreover, the resultant plots showed that there is strong correlation between the formula found in literature and the one derived on the basis of the fit of data sets in this study. In addition, it was found that the biodistribution behaviors of the developed kit and the commercial one were very close. The obtained results suggest that the developed DTPA has practically the same kinetics as the commercial one.