(R)-[11C]PK11195 has been widely used as a PET probe for imaging TSPO expression in animal models and humans with various CNS diseases, including glioma, stroke, HSE and neurodegenerative disorders such as Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis and Parkinson’s disease [5, 8, 11, 12]. Here, TSPO is linked to herpes simplex encephalitis.