Imaging inflammation holds immense potential for advancing the diagnosis, treatment and prognosis of many conditions1–3. The lack of a specific and sensitive positron emission tomography (PET) probe to detect inflammation is a critical challenge. To bridge this gap, we present CD45-PET imaging, which detects inflammation with exceptional sensitivity and clarity in several preclinical models. Notably, the intensity of the CD45-PET signal correlates robustly with the severity of disease in models of inflammatory lung and bowel diseases, outperforming 18F-fluorodeoxyglucose PET, the most widely used imaging modality for inflammation globally. Longitudinal CD45-PET imaging further enables precise monitoring of dynamic changes in tissue-specific inflammatory profiles. Finally, we developed a human CD45-PET probe for clinical translation that effectively detects human immune cells in a humanized mouse model. CD45-PET imaging holds substantial clinical promise, offering a tool for guiding diagnostic and therapeutic decisions for inflammatory diseases through a precise, whole-body assessment of the inflammation profiles of individual patients.
