Serious kidney disease, involving substantial impairment of function, affects approximately 3.5 million Americans. Quantitative measurement of regional and global renal perfusion can provide important diagnostic information in the evaluation of such patients. Despite an intense search within the research community for a suitable non-invasive method for such measurements, existing techniques have severe limitations including lack of quantification (MR about), dependence on highly skilled users (color Doppler) or inappropriateness for use in humans (radiolabeled microspheres). Although global kidney function can be assessed using clearance indicators, these techniques provide no direct perfusion information. With a suitable radioactive agent, PET imaging can provide absolute quantification of regional blood flow with excellent spatial resolution and can be applied conveniently in humans. We propose adaptation of a PET imaging technology under development at FF1 for myocardial perfusion imaging to this unique renal application. We will employ the PET agent, Cu-62 ETS, which has a short 9.7 minute physical half-life, permitting safe, repeated use in humans and which can be nationally distributed through use of a PTI developed generator. In pilot studies, this agent has demonstrated excellent high flow myocardial uptake. Therefore, in light of the very high flow levels seen in normal renal function, this perfusion agent is uniquely suited for application in this important field. The proposed work will involve refreshment of the radiochemical process for production of the Cu-62 ETS and the necessary work for preparation of an Investigational New Drug Application. In addition the agent will be investigated for measurement of regional renal blood flow in pilot studies in pigs undergoing shock-wave lithotripsy versus 0-15 water PET, radiolabeled microspheres, and blood and urine clearance indicators. Given the strength of PET and the characteristics of the Cu-ETS tracer, this imaging procedure could provide an ideal non-invasive technique for absolute quantitative measurement of both regional and global renal blood flow with far-reaching benefits in patient management and diagnosis.
A technology which enables quantitative measurement of global and regional renal perfusion could have a sizable and clinically significant market. This research would facilitate application of the powerful PET technique to this field and would provide a convenient, low-cost source of radiopharmaceutical for this application. As few radiotracers have proved adequate for imaging renal blood flow, Cu-ETS has a large potential commercial market. Furthermore, its utility for other perfusion imaging applications (e.g. heart) makes it attractive for broad clinical application.
