[18F]-labeled Substance P Antagonist Receptor Quantifier

**Semantic type:** Indicator, Reagent, or Diagnostic Aid|Organic Chemical|Pharmacologic Substance

**Definition:** A radioconjugate consisting of the positron emitting radioisotope fluorine F 18 conjugated to the substance P antagonist receptor quantifier (SPA-RQ) used in radioimaging. [18F]-labeled substance P antagonist receptor quantifier is an antagonist of the neurokinin 1 (substance P) receptor (NK1R) and can function as a positron emission tomography (PET) imaging agent for detecting NK1R-expressing cells and tissues. NK1Rs are frequently expressed on the plasma membranes of tumor cells from glioblastoma and breast and pancreatic carcinomas.

**Synonyms:** - (18F)-L-829165 - L-829165 F-18 - SPA-RQ F-18 - [18F]-labeled substance P antagonist receptor quantifier - [18F]SPA-RQ - [18F]SPA-RQ