Radio frequency spectral analysis for in-vitro or in-vivo environments
First Claim
1. A method, capable of in vivo operation, for determining concentration of glucose in the presence of a second substance that includes NaCl in a specimen that includes blood, the method including the following steps:
- (a) subjecting said specimen to radio frequency signals having a frequency regime ranging from about 0.1 Mhz to about 5 Ghz;
(b) at a first frequency regime, using at least some of said radio frequency signals to obtain data proportional to magnitude of concentration of said second substance in said specimen;
(c) at a second frequency regime, using at least some of said radio frequency signals to obtain data proportional to combined concentration in said specimen of said glucose and said second substance; and
(d) using data from said first frequency regime and data from said second frequency regime to obtain a measure of concentration of said glucose in said specimen.
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Accused Products
Abstract
Concentration of a target chemical in the presence of other substances in a specimen is determined by subjecting the specimen to radio frequency electromagnetic components, sequentially or otherwise, ranging to about 5 GHz. The reflected and/or transmitted signal real and imaginary components at the specimen are spectrally examined as a function of frequency to identify the presence and/or concentration of the chemical of interest. Such examination includes analysis of the effective complex impedance presented by the specimen, and/or effective phase shift between the transmitted and reflected signal at the specimen. The effects upon glucose concentration measurements of varying electrolytes, primarily NaCl, can be nulled-out by examining impedance magnitude at a cross-over frequency, for example about 2.5 GHz. NaCl concentration exhibits a very linear relationship with phase shift change at frequencies in the 2 GHz-3 GHz range. In a specimen that is blood, such phase shift measurements provide data proportional to NaCl concentration. Impedance magnitude measurements using 1 MHz to 400 MHz frequencies provides a measure of combined concentration of glucose and NaCl. The phase shift data may then be used to substrate out the NaCl concentration from the combined concentration, to yield a good measure of glucose concentration. Such tests may be conducted in-vitro or in-vivo and lend themselves to blood level glucose analyses by diabetics.
314 Citations
17 Claims
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1. A method, capable of in vivo operation, for determining concentration of glucose in the presence of a second substance that includes NaCl in a specimen that includes blood, the method including the following steps:
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(a) subjecting said specimen to radio frequency signals having a frequency regime ranging from about 0.1 Mhz to about 5 Ghz; (b) at a first frequency regime, using at least some of said radio frequency signals to obtain data proportional to magnitude of concentration of said second substance in said specimen; (c) at a second frequency regime, using at least some of said radio frequency signals to obtain data proportional to combined concentration in said specimen of said glucose and said second substance; and (d) using data from said first frequency regime and data from said second frequency regime to obtain a measure of concentration of said glucose in said specimen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method, capable of in vivo operation, for determining concentration of glucose in the presence of a second substance that includes NaCl in a specimen that includes blood, the method including the following steps:
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(a) subjecting said specimen to radio frequency signals at a cross-over frequency at which frequency concentration effects of said second substance are essentially nulled-out; and (b) determining from data taken at said cross-over frequency concentration of said glucose. - View Dependent Claims (12, 13, 14)
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15. A system, capable of in vivo operation, for determining concentration of a first chemical in the presence of a second substance in a specimen, including:
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a transmitter outputting radio frequency signals having a frequency regime ranging from about 0.1 MHz to about 5 GHz; at least one probe, coupling to said transmitter, contacting a portion of said specimen; and a receiver-signal processor system, coupled to said at least one probe, that analyzes at least some of said radio frequency signals present at said probe; said receiver-signal processor system providing data including at least impedance and/or phase shift present at an interface between said specimen and said at least one probe; wherein data provided by said receiver-signal processor system is used to determine said concentration of said first chemical in said specimen. - View Dependent Claims (16, 17)
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Specification