TISSUE PATHLENGTH RESOLVED NONINVASIVE ANALYZER APPARATUS AND METHOD OF USE THEREOF
An analyzer apparatus and method of use thereof is configured to dynamically interrogate a sample. For example, an analyzer using light interrogates a tissue sample using a temporal resolution system on a time scale of less than about one hundred nanoseconds. Optionally, near-infrared photons are introduced to a sample with a known illumination zone to detection zone distance allowing calculation of parameters related to photon pathlength in tissue and/or molar absorptivity of an individual or group through the use of the speed of light and/or one or more indices of refraction. Optionally, more accurate estimation of tissue properties are achieved through use of: knowledge of incident photon angle relative to skin, angularly resolved detector positions, anisotropy, skin temperature, environmental information, information related to contact pressure, blood glucose concentration history, and/or a skin layer thickness, such as that of the epidermis and dermis.
1 . An apparatus for determination of an analyte property of a subject, comprising:
a near-infrared analyzer, comprising:
a source configured to deliver a sub-microsecond burst of near-infrared light in the range of 1000 to 2500 nanometers;
a temporal resolution gating system configured to collect signal from the burst of near-infrared light during a time period of at least one time delayed gated window, the time period comprising a period greater than one femtosecond and less than one nanosecond after a midpoint of the burst of the near-infrared light; and
a data processing system configured to use the signal and the time period of the at least one delayed gated window in determination of a glucose concentration.
2 . The apparatus of claim 1 , said data processing system configured to resolve a pathlength of the near-infrared light in the subject using the signal from the burst of near-infrared light in the at least one time delayed gated window, the pathlength used in said data processing system in the determination of the glucose concentration.
3 . The apparatus of claim 1 , said data processing system configured to use the time period of the at least one time delayed gated window in determination of a product of pathlength and molar absorptivity.
4 . The apparatus of claim 1 , wherein said analyzer further comprises:
at least one optic configured to vary radial distance, by at least one millimeter as a function of time, between a middle of an illumination zone of the burst of near-infrared light on the subject and a middle of a detection zone of a detection optic of said analyzer.
5 . The apparatus of claim 4 , wherein the radial distance comprises a set of at least four mean distances as a function of scan number, wherein the signal comprises a set of at least ten sub-signals correlating to said set of four mean distances.
6 . The apparatus of claim 1 , wherein said data processing system uses a database, said database configured to store at least one physiology parameter, said physiology parameter comprising at least one of an epidermal thickness and a dermal thickness, said data processing system configured to use at least one of the epidermal thickness and the dermal thickness in the determination of the glucose concentration.
7 . The apparatus of claim 1 , in the determination of the glucose concentration, said data processing system configured to use at least one of:
an anisotropy value; and
an index of refraction.
8 . The apparatus of claim 1 , in the determination of the glucose concentration, said data processing system configured to use at least one of:
a scattering coefficient; and
an absorbance of any of water, protein, and fat.
9 . The apparatus of claim 1 , wherein said analyzer further comprises:
a sample interface configured to not contact the subject during collection of the signal.
10 . The apparatus of claim 1 , wherein said analyzer further comprises:
a sample interface configured to contact at least one of the subject and a coupling fluid during collection of the signal.
11 . The apparatus of claim 1 , wherein said analyzer further comprises:
a fiber optic bundle comprising:
a first fiber optic configured to deliver the burst of the near-infrared light to the subject, said first fiber optic comprising a first cross-sectional area; and
a second fiber optic configured to deliver the burst of the near-infrared light to the subject, said second fiber optic comprising a second cross-sectional area, said second cross-sectional area at least ten percent larger than said first cross-sectional area.
12 . The apparatus of claim 1 , wherein said analyzer further comprises:
a vibration reduction system, wherein said vibration reduction system maintains a gap between a sample interface of said analyzer and the subject by monitoring shaking of the subject and adjusting physical position of said sample interface relative to the subject.
13 . The apparatus of claim 1 , wherein said analyzer further comprises:
a first sample side optic configured to deliver the burst of light to the subject at a first mean incident angle relative to an axis normal to a sample site of the subject,
a second sample side optic configured to deliver the burst of light to the subject at a second mean incident angle relative to the axis normal to the sample site of the subject, the first mean incident angle at least ten degrees larger than the second mean incident angle.
14 . A method for determination of an analyte property of a subject having skin, comprising the steps of:
delivering a spectral burst of near-infrared light at least within the range of 1000 to 2500 nanometers from a source of an analyzer to an illumination region of the skin of the subject;
generating a signal during at least one time period using a temporal resolution gating system to detect the burst of light in at least one time delayed gated window between one hundred picoseconds and one hundred nanoseconds after origination of the burst of the near-infrared light; and
processing the signal using the at least one time period and the signal to generate a glucose concentration of the subject.
15 . The method of claim 14 , wherein said step of processing uses the time of said at least one time delayed gated window and the signal to generate an optical pathlength of the burst of the near-infrared light in the subject.
16 . The method of claim 14 , wherein said step of processing estimates a molar absorptivity of the subject.
17 . The method of claim 14 , further comprising the step of:
adapting an optical configuration of the analyzer using the molar absorptivity.
18 . The method of claim 14 , wherein said step of processing further comprises the steps of:
sending a form of the signal to a smart phone;
analyzing the form of the signal using the smart phone to generate a result; and
using said smart phone to convey the result to the subject.
19 . The method of claim 14 , further comprising the steps of:
using said analyzer to gather information from a sensor external to said analyzer; and
relaying a form of the information to a cell phone.
20 . The method of claim 14 , further comprising the step of:
varying radial distance of the burst of light onto the subject relative to a zone monitored by a detector of said analyzer by at least one millimeter in a ten second time period.
21 . A method for determination of a glucose concentration of a subject, comprising the steps of:
using a temporal resolution analyzer to time near-infrared photon traversal through skin using a time resolved gating system and to gather a signal at a detection time period of the time resolved gating system; and
using the detection time period and the signal to noninvasively determine a glucose concentration of the subject.
22 . The method of claim 21 , wherein said detection time comprises a time period greater than one femtosecond and less than one nanosecond after generation of a burst of light by said analyzer, wherein the signal is collected during said time period.
23 . The method of claim 21 , wherein said detection time comprises a time period greater than ten microseconds and less than one-tenth of a second after generation of a burst of light by said analyzer, wherein the signal is collected during said time period.