Apparatus and methodology for determining oxygen in biological systems
First Claim
1. Apparatus for measuring oxygen tension in a biological system having a paramagnetic located therein, comprising(a) magnetic means for selectively applying a magnetic field of selectable strength to the biological system,(b) electromagnetic means for selectively applying electromagnetic radiation having a selected substantially constant frequency to the paramagnetic material in the biological system,(c) detection means for detecting the electron paramagnetic spectra of the biological system, said spectra having a selected peak-to-peak line width that is indicative of said oxygen tension in the biological system,(d) resonator means coupled to the electromagnetic means,said resonator means including means for tuning said resonator means to the constant frequency of said electromagnetic means to maintain a substantially constant resonant frequency in response to movements in the biological system,(e) console means in communication with said detection means for displaying said spectra, and(f) computer means connected to said console means for controlling said apparatus, and for analyzing said spectra to determine said oxygen tension.
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Abstract
The invention provides apparatus and methods for measuring oxygen tensions in biological systems utilizing physiologically acceptable paramagnetic material, such as India ink or carbon black, and electron paramagnetic resonance (EPR) oximetry. India ink is introduced to the biological system and exposed to a magnetic field and an electromagnetic field in the 1-2 GHz range. The EPR spectra is then measured at the biological system to determine oxygen concentration. The EPR spectra is determined by an EPR spectrometer that adjusts the resonator to a single resonator frequency to compensate for movements of the biological system, such as a human or animal. The biological system can also include other in vivo tissues, cells, and cell cultures to directly measure pO2 non-destructively.
188 Citations
18 Claims
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1. Apparatus for measuring oxygen tension in a biological system having a paramagnetic located therein, comprising
(a) magnetic means for selectively applying a magnetic field of selectable strength to the biological system, (b) electromagnetic means for selectively applying electromagnetic radiation having a selected substantially constant frequency to the paramagnetic material in the biological system, (c) detection means for detecting the electron paramagnetic spectra of the biological system, said spectra having a selected peak-to-peak line width that is indicative of said oxygen tension in the biological system, (d) resonator means coupled to the electromagnetic means,said resonator means including means for tuning said resonator means to the constant frequency of said electromagnetic means to maintain a substantially constant resonant frequency in response to movements in the biological system, (e) console means in communication with said detection means for displaying said spectra, and (f) computer means connected to said console means for controlling said apparatus, and for analyzing said spectra to determine said oxygen tension.
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5. A system for determining oxygen tension within a biological system, comprising
means for introducing india ink into the biological system, magnetic means for applying a first magnetic field to the biological system, radiation means for applying electromagnetic radiation having a frequency between about 100 MHz and about 5 GHz to the biological system to excite the india ink to a higher energy state, said excited india ink then relaxing at a rate dependent upon the presence of oxygen in the biological system, and means for determining the electron paramagnetic resonance spectra of the biological system, said spectra being indicative of the oxygen tension within the biological system.
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17. A system for determining oxygen tension within a biological system, comprising
means for introducing an electron paramagnetic material into the biological system, magnetic means for applying a magnetic field to the biological system, radiation means for applying electromagnetic radiation having a selected substantially constant frequency to the biological system to excite the paramagnetic material, resonator means operable at a selected resonant frequency, tuning means for tuning said resonant frequency of said resonator to match said constant frequency radiation means to maintain a constant resonant frequency in response to movements in the biological system, and means for determining the electron paramagnetic resonance spectra of the biological system, said spectra being indicative of the oxygen tension within the biological system.
Specification