Measuring tumor blood flow with (H2O)-O-15: Practical considerations

The ability to measure blood flow to tumors non-invasively may be of import ance in monitoring tumor therapies, assessing drug delivery, and understand ing tumor physiology. Of all the radiotracer methods that have been propose d to measure tumor blood flow, the method based on labeled water-(H2O)-O-15 -may be the most applicable to tumors. It is highly diffusible, does not pa rticipate significantly in metabolic processes during the short times invol ved in the study, and its uptake and clearance can be easily modeled. We pr esent here an analysis of the bolus injection water methodology and how it might best be used to monitor tumor blood flow. Several different formulati ons of the basic methodology, based on previous applications in the heart a nd brain, are discussed. Potential problems of adapting these previous meth odologies to tumor blood flow are presented. NUCL MED BIOL 27;7:671-676, 20 00. (C) 2000 Elsevier Science Inc. All rights reserved.