Optical determination of in vivo properties
First Claim
1. A method for determining an in vivo blood property, the method comprising:
- irradiating a first location of a subject'"'"'s skin with incident light;
detecting exit light resulting from irradiating the first location, at least some of the exit light having passed through a blood vessel of the subject and exited the subject'"'"'s skin at a distance from the first location;
irradiating a second location of the subject'"'"'s skin with incident light;
detecting reference light resulting from irradiating the second, different location, at least some of the reference light having passed through at least some subsurface tissue of the subject without passing through the blood vessel; and
determining the in vivo blood property based on the first exit light and the reference light.
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Accused Products
Abstract
A system and method for determining an in vivo property of a tissue or blood is described. The in vivo property may be a hematocrit value, a hemoglobin concentration, or a combination thereof. The system can automatically determine a location of a subcutaneous blood vessel. Based on the automatically determined location, the system illuminates the blood vessel with a light beam and detects light resulting from the illumination. The system determines the in vivo property based on the detected light. Alternatively, or in combination, the system displays an image corresponding to a spatial relationship between a subcutaneous blood vessel and a light beam. Based on the image, an operator can adjust the light beam with respect to the blood vessel to have a selected spatial relationship. The system determines an in vivo property based on the illumination of the blood vessel when the light beam has the selected spatial relationship.
127 Citations
20 Claims
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1. A method for determining an in vivo blood property, the method comprising:
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irradiating a first location of a subject'"'"'s skin with incident light;
detecting exit light resulting from irradiating the first location, at least some of the exit light having passed through a blood vessel of the subject and exited the subject'"'"'s skin at a distance from the first location;
irradiating a second location of the subject'"'"'s skin with incident light;
detecting reference light resulting from irradiating the second, different location, at least some of the reference light having passed through at least some subsurface tissue of the subject without passing through the blood vessel; and
determining the in vivo blood property based on the first exit light and the reference light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of determining an in vivo blood property, comprising:
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detecting first exit light I1,1 resulting from irradiating a first location of a subject'"'"'s skin with incident light, at least some of the first exit light having passed through a blood vessel of the subject and exited the subject'"'"'s skin at a first distance from the first location, detecting first reference light R1,1 resulting from irradiating the first location of the subject'"'"'s skin with second incident light, at least some of the first reference light having passed through subsurface tissue of the subject and exited the subject'"'"'s skin at the first distance from the first location, the second incident light having a wavelength that is more attenuated by blood than a wavelength of the first incident light, detecting second reference light I2,T resulting from irradiating a second, different location of the subject'"'"'s skin with third incident light, at least some of the second reference light having passed through at least some subsurface tissue of the subject without passing through the blood vessel, wherein detecting the second reference light I2,T comprises detecting light that has exited the subject'"'"'s skin through an area of the subject'"'"'s skin that is larger than an area through which either the first exit light or first reference light exited the subject'"'"'s skin, detecting third reference light I2,1 resulting from irradiating the second, different location of the subject'"'"'s skin with incident light, at least some of the third reference light having passed through subsurface tissue of the subject without passing through the blood vessel and exited the subject'"'"'s skin at the first distance from the second location, determining the in vivo blood property based on the light I1,1, R1,1, I2,T, I2,1. - View Dependent Claims (14, 15, 16)
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17. A method, comprising:
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automatically determining a location of a blood vessel of a subject;
illuminating the blood vessel with light by illuminating a first location of skin of the subject with incident light;
detecting exit light resulting from illuminating the first location of skin;
illuminating a second location of the skin of the subject with incident light, the second location being spaced apart from the first location;
detecting reference light resulting from illuminating the second location of skin, at least some of the reference light having passed through at least some sub-surface tissue of the subject without passing through the blood vessel; and
determining an in vivo blood property based on the exit light and the reference light. - View Dependent Claims (18)
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19. A system, comprising:
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a light source configured to irradiate first and second spaced-apart locations of a subject'"'"'s skin with incident light;
a detector configured to;
detect exit light resulting from irradiating the first location, at least some of the exit light having passed through a blood vessel of the subject and exited the subject'"'"'s skin at a distance from the first location;
detect reference light resulting from irradiating the second, different location, at least some of the reference light having passed through at least some subsurface tissue of the subject without passing through the blood vessel; and
a processor configured to determine the in vivo blood property based on the first exit light and the reference light. - View Dependent Claims (20)
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Specification