Water protons within Oxygen-17 labeled water (H217O protons) (H217O protons)

Water protons within H217O molecules refer to the hydrogen nuclei in water molecules containing the stable isotope Oxygen-17. This entity is not a traditional therapeutic target such as a receptor or enzyme; rather, it is a diagnostic probe used in magnetic resonance imaging (MRI) and spectroscopy (Source: PubMed, PMID: 31553456). The Oxygen-17 nucleus possesses a quadrupolar moment and a nuclear spin of 5/2, which facilitates the relaxation of nearby water protons through scalar coupling (Source: Wikipedia, Oxygen-17). This effect allows for the indirect detection of Oxygen-17 by monitoring changes in the T2 or T1rho relaxation times of the water protons, a technique often referred to as the proton-detected 17O approach (Source: NIH, Oxygen-17 MRI). Biologically, H217O is produced as a metabolic byproduct when 17O2 gas is reduced by cytochrome c oxidase during mitochondrial oxidative phosphorylation (Source: Journal of Cerebral Blood Flow & Metabolism). By tracking the accumulation of these water protons, clinicians and researchers can non-invasively quantify the cerebral metabolic rate of oxygen consumption (CMRO2) and regional blood flow. This imaging modality is particularly valuable for assessing metabolic deficits in neurodegenerative disorders like Alzheimer's disease, evaluating tissue viability in ischemic stroke, and characterizing the hypermetabolic state of cancerous tumors (Source: PubChem, Oxygen-17).

Other names

17O-labeled water protonsOxygen-17 water protonsH2(17O) protonsWater-17O protons

The 17O nucleus induces T2 and T1rho relaxation shortening of surrounding water protons via scalar relaxation of the second kind, enabling indirect MRI detection of metabolic oxygen consumption.