Background: Nanoparticles (NPs) have gained great importance during the last decades for developing new therapeutics with improved outcomes for biomedical applications due to their nanoscale size, surface properties, loading capacity, controlled drug release, and distribution. Among the carbon-based nanomaterials, one of the most biocompatible forms of graphene is gra-phene quantum dots (GQDs). GQDs are obtained by converting 2D graphene into zero-dimensional graphene nanosheets. Moreover, very few reports in the literature reported the pharmacokinetic studies proving the safety and effectiveness of GQDs for in vivo applications. Objectives: This study evaluated the pharmacokinetics of GQDs radiolabeled with 99mTc, adminis-tered intravenously, in rodents (Wistar rats) in two conditions: short and long periods, to compare and understand the biological behavior. Methods: The graphene quantum dots were produced and characterized by RX diffractometry, Ra-man spectroscopy, and atomic force microscopy. The pharmacokinetic analysis was performed fol-lowing the radiopharmacokinetics concepts, using radiolabeled graphene quantum dots with techne-tium 99 metastable (99mTc). The radiolabeling process of the graphene quantum dots with 99mTc was performed by the direct via. Results: The results indicate that the pharmacokinetic analyses with GQDs over a longer period were more accurate. Following a bicompartmental model, the long-time analysis considers each pharmacokinetic phase of drugs into the body. Furthermore, the data demonstrated that short-time analysis could lead to distortions in pharmacokinetic parameters, leading to misinterpretations. Conclusion: The evaluation of the pharmacokinetics of GQDs over long periods is more meaning-ful than the evaluation over short periods.