Spiperone is primarily used in scientific research as a radioligand for binding assays to study dopamine receptors, particularly the D2 and D4 subtypes. It acts as a high-affinity antagonist, making it valuable for mapping receptor distribution in the brain and investigating the function of dopaminergic pathways. Due to its specificity, spiperone is also employed in positron emission tomography (PET) studies when labeled with radioactive isotopes, allowing non-invasive imaging of dopamine receptor density in living organisms. This application is especially useful in neuroscience and psychiatry research, including studies on schizophrenia, Parkinson’s disease, and other disorders involving dopamine signaling. Additionally, spiperone has been used historically in the development and validation of new antipsychotic drugs to assess receptor binding profiles.