[18F]SPA-RQ

[18F]SPA-RQ is a radiopharmaceutical used as a positron emission tomography (PET) imaging agent for the neurokinin 1 receptor (NK1R), also known as the substance P receptor. It is an antagonist of NK1R and enables non-invasive quantification and localization of NK1 receptors in vivo, particularly in the human brain. The compound consists of SPA-RQ labeled with fluorine‑18 ([^18F]), a positron-emitting radioisotope. This tracer has been used to study NK1R distribution in both central and peripheral tissues, supporting research into neuropsychiatric disorders such as mood disorders, anxiety/stress responses, pain modulation, emesis control, and potentially tumor imaging where NK1Rs are overexpressed[7][6][3]. It was initially developed by the National Cancer Institute for clinical research applications[2].

Other names

Substance P antagonist receptor quantifier F‑18UNII 4YL3GT1EV9UNII4YL3GT1EV9UNII-4YL3GT1EV9