This study presents a preliminary investigation of the application of MAPbI 3 perovskite solar cells (PSCs) as dosimeters for space and medical purposes. Specifically, it explores the effects of 6 MeV electron beam exposure on the performance and degradation mechanisms of PSC devices. The study also employs crystallographic, optical, and simulation-based analyzes to gain insights into the degradation process. The findings of this research lay the groundwork for the development of an advanced radiation detection structure, combining a scintillator with a photocounting PSC device, as a potential replacement for existing silicon photomultipliers in the future. The PSC devices exhibit an initial power conversion efficiency of approximately 14%. However, under electron fluences ranging from 3 to 21 kGy, a gradual degradation is observed, characterized by a decline in open-circuit voltage and short-circuit current. Beyond the 9 kGy threshold, the device performance deteriorates significantly, with a 52% decrease compared with the initial performance, which is primarily attributed to a decrease in the fill factor. Through X-ray diffraction, time-resolved photoluminescence, and density functional theory simulations, the research uncovers that continuous electron beam exposure induces the formation of crystallographic defects and shallow traps, leading to the gradual deterioration of device performance postirradiation.