Ischemic stroke (IS) was identified as the second most common cause of death worldwide in 2019 according to a survey [1]. A large percentage of patients remain with permanent consequences that can persist even fifteen years after the event [2]. This is also associated with economic impacts on healthcare and supportive services, which amounted to approximately 60 billion euros in the EU in 2017 [3]. The key to success is time. IS can already be precisely diagnosed nowadays. However, in each specific situation, there is a problem with detecting the onset of stroke, which is crucial for choosing the appropriate treatment and thus saving lives. Today’s commonly used medical scanning devices can only visualize clots with high erythrocyte content. Other forms of thrombi become very difficult to recognize [4]. Polyiodinated biodegradable nanoparticles (IoNPs) have the potential to solve this problem. The current preclinical phase of our project is focused on researching the pharmacokinetics of these potential IoNPs theranostics in the body. A unique method LA-ICP-MS is used to determine the IoNPs distribution. The study was supported by Grant Agency of Masaryk University – Excellent diploma thesis, MUNI/C/0002/2023.