We have developed a new system which, for the first time, makes it feasible to measure pO2 in the clinical setting with the accuracy, sensitivity, and repeatability needed for effective clinical use. The method measures at defined sites in the region(s) of interest and measurements can be made simultaneously at several sites. The existing methods for making experimental measurements of pO2 in cells and tissues, e.g., the Clark electrode, fluorescence quenching, O2 binding to myoglobin, chemiluminescence, phosphorescence quenching, and spin label oximetry are useful but have certain limitations, especially when used in vivo. None of these techniques appears to have the potential for making repeated measurements in the clinical setting.
Our method, on the other hand, is particularly advantageous for clinical measurements of oxygen in tissues in vivo. Once the material used to measure pO2 is injected into the tissue of interest or applied non-invasively, pO2 can be measured conveniently, rapidly, and repetitively in a NON-INVASIVE MANNER with a device designed and constructed at Dartmouth. The material used to measure pO2 is already clinically approved and thus can be immediately used in humans to measure oxygen in clinical setting. The technology required to make the measurements can be mass produced at a modest cost and the operation of the apparatus can be carried out by technicians without extensive special training.
The availability of a method to make sensitive, accurate, and repeated measurements of the pO2 in tissues would be of great clinical significance, especially for the optimization of cancer therapy and for aiding in the diagnosis and treatment of vascular disease. In clinical oncology such measurements are likely to be used initially to determine the presence of a high degree of hypoxia, in order to plan an optimum approach for that tumor. Subsequent measurements will enable the therapeutic oncologist to monitor the response of the pO2 of the tumor to the initial therapeutic regime, in order to decide whether the therapy should be modified. In peripheral vascular disease this technique will permit the repeated non-invasive assessment of the pO2 in the target tissues, providing an objective measure of the course of the disease and the response to medical and surgical therapy. This would be of particular value in the care of diabetics and others with impaired circulation to their legs and feet.
There are a number of other potential clinical applications as well, for any other diseases in which the level of oxygen in the tissues would provide clinically useful information (e.g. any disease involving impaired circulation or ischemia). As a consequence, the proposed system could become a part of every well equipped hospital, especially in the oncology and cardiovascular sections of the hospital. This could involve the placement of 1 to 10 of these instruments in virtually every hospital that treats patients with these types of diseases.
There also is a considerable commercial potential for the development of the system for experimental purposes. The capabilities provided by our system could be of significant value for a wide range of experimental studies in small and large animals. These studies would include not only those with direct link to the clinical areas described above, but also for a wide range of studies of basic biology and physiology, because of the importance of oxygen concentrations in most physiological and pathophysiological processes.
The feasibility of Dartmouth's approach has now been fully demonstrated in experimental studies in animals and in an experiment with a human volunteer. We now are embarking on a series of experiments to provide more extensive data on the properties of the material, used to measure pO2, and the sensitivity and accuracy of our approach.
The apparatus, methodology, and non-invasive approach are claimed in the issued United States Patent Nos. 5,494,030, 5,706,805, and 5,833,601, and in the issued Canadian Patent No. 1,450,205. We are seeking an industrial partner who can participate in the refinement of this approach into a device suitable for routine clinical use and is interested in commercialization of this technology. (Ref: J55)
Last Updated: 7/24/12