METHOD AND DEVICE FOR DETERMINING A PROPERTY OF LIVING TISSUE
First Claim
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1. A method for measuring a property c of living tissue, which property c affects the complex dielectric permittivity ∈
- (ω
) of said tissue, comprising the steps ofapplying an electrode arrangement to a skin region of said tissue,generating, by means of said electrode arrangement, a plurality of electrical fields in said tissue at different frequencies ω
w with w=1 to W and measuring, for each of said frequencies, a signal sw with w=1 to W, depending on the dielectric permittivity ∈
(ω
w) as seen by said electrode arrangement at the frequency ω
w, thereby generating a measured dataset {(s1, ω
1), . . . (sW, ω
W)},using dispersion parameters pmn with m=1 M with M>
1 and n=1 . . . N, wherein said dispersion parameters pmn are parameters of a dispersion function H describing a dispersion of the dielectric permittivity ∈
m of a virtual homogeneous tissue layer m in said skin region by
∈
m(ω
)=H(pm1, . . . , pmN,ω
),with m=1 . . . M,fitting a function F1
s(ω
)=F1(p11, . . . , pMN,ω
)to said measured dataset {(s1, ω
1), . . . (sW, ω
W)} by varying at least part of said dispersion parameters pmn, wherein said function F is given by
F1(p11, . . . pWL,ω
)=F0(∈
1(ω
), . . . ∈
M(ω
))with a function F0(∈
1(ω
), . . . ∈
L(ω
)) describing the signal s(ω
) measured if said layers 1 . . . M have the dielectric permittivities ∈
1(ω
), . . . ∈
M(ω
),said method further comprising the step of using at least part of the varied dispersion parameters pmn for calculating said property c.
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Abstract
The invention relates to a measurement of tissue properties, in particular glucose, by measuring the response of the tissue to an applied electric field. The tissue is modeled by a System of homogeneous layers. In one approach, a plurality of electrical fields are generated in the tissue at different frequencies. For each of the fields, a signal depending on the dielectric permittivity as seen by the electrode arrangement at the frequency is measured, thereby generating a measured dataset. In another approach the different electrode configurations can be used to achieve different penetration depths in the desired layers. A function is then fitted to the dataset by varying at least some parameters of the function. These parameters describe the dispersion of the dielectric permittivity of a plurality of layers in the tissue. At least part of the parameters obtained in this fitting procedure are then used for determining the desired tissue property. Furthermore a combination of these two approaches can be used to optimize the uniqueness of the Solution of the fitting procedure for changes at a specific depth.
32 Citations
15 Claims
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1. A method for measuring a property c of living tissue, which property c affects the complex dielectric permittivity ∈
- (ω
) of said tissue, comprising the steps ofapplying an electrode arrangement to a skin region of said tissue, generating, by means of said electrode arrangement, a plurality of electrical fields in said tissue at different frequencies ω
w with w=1 to W and measuring, for each of said frequencies, a signal sw with w=1 to W, depending on the dielectric permittivity ∈
(ω
w) as seen by said electrode arrangement at the frequency ω
w, thereby generating a measured dataset {(s1, ω
1), . . . (sW, ω
W)},using dispersion parameters pmn with m=1 M with M>
1 and n=1 . . . N, wherein said dispersion parameters pmn are parameters of a dispersion function H describing a dispersion of the dielectric permittivity ∈
m of a virtual homogeneous tissue layer m in said skin region by
∈
m(ω
)=H(pm1, . . . , pmN,ω
),with m=1 . . . M, fitting a function F1
s(ω
)=F1(p11, . . . , pMN,ω
)to said measured dataset {(s1, ω
1), . . . (sW, ω
W)} by varying at least part of said dispersion parameters pmn, wherein said function F is given by
F1(p11, . . . pWL,ω
)=F0(∈
1(ω
), . . . ∈
M(ω
))with a function F0(∈
1(ω
), . . . ∈
L(ω
)) describing the signal s(ω
) measured if said layers 1 . . . M have the dielectric permittivities ∈
1(ω
), . . . ∈
M(ω
),said method further comprising the step of using at least part of the varied dispersion parameters pmn for calculating said property c. - View Dependent Claims (2, 3, 4, 5, 6, 7, 12, 13, 14)
fitting a model function L
s=L(r1, . . . rT, . . . ∈
Mk)to said vectors vk by varying model parameters r1, . . . rT of said model function L and using the varied model parameters r1, . . . rT for calculating
F0(∈
1(ω
), . . . ∈
L(ω
))=L(r1, . . . rT,∈
1(ω
),∈
L(ω
)).
- (ω
-
3. The method of claim 2, wherein said model function L is linear in r1, . . . rT.
-
4. The method of claim 1, wherein
-
5. The method of claim 1, wherein
-
6. The method of claim 1, wherein M=2.
-
7. The method of any claim 1, wherein a thickness of a topmost layer of said skin area is between 10 and 300 μ
- m.
-
12. A device for measuring a property c of living tissue, in particular a glucose level, which device comprises a control unit adapted to carry out the steps of claim 1.
-
13. The device of claim 12 further comprising:
-
an electrode arrangement, a signal source controlled by said control unit and generating an electrical signal to be applied to said electrode arrangement for generating an electrical field in said tissue, and a detector for measuring a response from said tissue to said electrical field and for determining the at least one property therefrom.
-
-
14. A method as claimed in claim 1, wherein said property of a living tissue is a glucose level.
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8. A method for measuring a property c of living tissue, which property c affects the complex dielectric permittivity c of said tissue, comprising the steps of:
-
applying an electrode arrangement to a skin region of said tissue, generating, by means of said electrode arrangement, a plurality of electrical fields in said tissue, by applying voltages to different configurations u with u=1 to U and U>
1 of said electrode arrangement, and measuring, for each of said configurations, a signal su with u=1 to U, depending on the dielectric permittivity ∈
u as seen by said electrode arrangement for configuration u, thereby generating a measured dataset {s1, . . . sU},using a set of dielectric parameters ∈
1, . . . ∈
M and thickness parameters d1, . . . dM−
1 describing the dielectric permittivity and thickness of a set of M homogeneous tissue layers in said skin region,solving a set of equations
su=F0u(∈
1, . . . ∈
M,d1, . . . dM−
1),with u=1 to U, by varying at least part of said complex dielectric parameters ∈
1, . . . ∈
m and/or said thickness parameters d1, . . . dM−
1, wherein said function F0u describes the signal su measured if said layers 1 . . . M have the complex dielectric parameters ∈
1, . . . ∈
m and thickness parameters d1, . . . dM−
1 and if the configuration u is used,said method further comprising the step of using at least part of the varied real and imaginary dielectric parameters ∈
1, . . . ∈
M and/or at least part of the thickness parameters d1, . . . dM−
1 for calculating said property c.- View Dependent Claims (9, 10, 11, 15)
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Current AssigneeSolianis Holding AG
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Original AssigneeSolianis Holding AG
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InventorsHuber, Daniel, Talary, Mark Stuart, Falco, Lisa, Dewarrat, Francois
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Application NumberUS12/809,099Publication NumberTime in Patent OfficeDaysField of SearchUS Class Current600/347CPC Class CodesA61B 5/0531 Measuring skin impedanceA61B 5/14532 for measuring glucose, e.g....
