Semiconductor Based Polarographic Oxygen System

This project will address the need for real-time, multi-site, continuous measurement of oxygenpartial pressure in vivo. A fabrication sequence for the construction of semiconductor basedpolarographic oxygen sensors will be developed. A set of masks will be used to fabricate isolatedpolarographic oxygen sensors for evaluation and optimization of the process and characterization of thesensors. The process will be incorporated into an integrated circuit fabrication sequence so thatmicroelectronic circuits can be manufactured simultaneously on the same substrate as the oxygensensors. These intelligent oxygen sensors will include a sensor, signal detection circuitry, and an analogto digital converter, and will be assembled into multisite, digital output probes. Each year over1,000,000 new cases of cancer are reported in the United States alone; nearly 80 percent of thosecases are treated with modalities for which oxygenation is a primary controlling factor. Radiotherapyrelies on the interaction of the applied radiation with oxygen present in tissue to produce the cytotoxicfree radicals O2- and HO-. Tissue oxygenation governs the selection of oxic or hypoxic chemotherapeu-tic agents. The sensors produced could also be used for a multitude of other applications, as tissueoxygenation is one of the most ubiquitous physiologic measurements.