In vivo measurement of regional brain tissue pH using positron emission tomography

Carbon-11-labeled dimethyloxazolidinedione ([11C]DMO) was injected intravenously into human subjects, and serial positron emission tomographic (PET) scans were obtained until brain-blood equilibration was achieved or could be accurately predicted from dynamic PET and 11C blood data. Knowledge of regional brain-blood partition coefficients for DMO, together with measurements of arterial blood hematocrit and pH, permitted the calculation of regional brain tissue and tumor pH (rpH). [11C]DMO PET rpH values were similar to rpH values derived from quantitative autoradiographic measurements of [14C]DMO concentrations in rat brain slices.