Device and method for photon absorption coefficient measurement

Patent metadata

Field	Value
Publication number	US-9357962-B2
Application number	US-201013321511-A
Country	US
Kind code	B2
Filing date	May 26, 2010
Priority date	Jun 10, 2009
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

The invention relates to a method and a device, suitable for the measurement of quantitative photon absorption coefficient in tissue, wherein the device comprises a first light source, suitable for generating photons, a light measurement element suitable for measuring at least one of: the intensity, the frequency, the frequency deviations and phase shift of the light to be measured, an ultrasound source, suitable for the generation of a defined sound wave pattern in a defined volume element within the tissue, wherein the ultrasound source is suitable for labelling the light, originating from the first light source or a second light source that enters the defined volume element within the tissue, and an ultrasound measurement element, suitable for measuring ultrasound, originating from the defined volume element within the tissue and generated by the light of the first light source that enters the defined volume element within the tissue.

First claim

The invention claimed is:

1. A device, configured for measurement of specific photon absorption coefficient (μ a ) in tissue based on combined photo-acoustic and acousto-optic measurements;
wherein the device comprises for photo-acoustic measurements:
a first light source configured for generating photons;
an ultrasound measurement element configured for measuring ultrasound originating from a defined volume element within the tissue and generated by light of the first light source that enters the defined volume element within the tissue;

wherein the device comprises for acousto-optic measurements:
a second light source configured for generating photons;
an ultrasound source, configured for generation of a defined sound wave pattern in the defined volume element within the tissue and configured for labelling light originating from the second light source that enters the defined volume element within the tissue; and
a light measurement element configured for measuring the amount of labelled light exiting the tissue;

wherein the device is provided with a processor, which is at least in communicative contact with the light measurement element and the ultrasound measurement element;
wherein the processor is configured to deduce from the amount of light generated by the second light source, and from the amount of labelled light originating from the defined volume element, an amount of light originating from the first light source actually entering the defined volume element; and
wherein the processor is further configured to deduce from the measured ultrasound generated in the defined volume element within the tissue by light originating from the first light source, and the amount of light from the first light source that actually entered the defined volume element within the tissue, the specific photon absorption coefficient (μ a ) of the defined volume element within the tissue.

2. The device according to claim 1 , wherein the light sources are lasers and are configured to dose the light in a pulsed or modulated way.

3. The device according to claim 1 , wherein the second light source is configured to generate light of the same wave length as the light generated by the first light source.

4. The device according to claim 1 , wherein the ultrasound source comprises a number of sound elements which are configured to provide a focus.

5. The device according to claim 4 , wherein the number of sound elements are configured to provide crossing beams of sound waves.

6. The device according to claim 1 , wherein the first light source is configured to be arranged on a first position and a second position relative to the tissue; and wherein the second light source is configured to be arranged on the first position, wherein the light measurement element is configured to be arranged substantially on the second position.

7. The device according to claim 1 , wherein the first light source and the second light source are configured to be arranged on a first position relative to the tissue and wherein the light measurement element is configured to be arranged substantially on the first position as well.

8. The device according to claim 1 , wherein the device is configured to scan through at least a portion of the tissue by measuring consecutive defined volume elements within the tissue, deducing the respective specific photon absorption coefficient (μ) of each of the defined volume elements and wherein the device is further configured to generate from the thus generated data a graphic representation of the tissue, wherein different regions with different specific absorption coefficients (μ a ) are configured to be visually determinable.

9. The device according to claim 1 , wherein the light sources comprise arrays or matrices of individual sources.

10. The device according to claim 1 , wherein the ultrasound source comprises arrays or matrices of individual sources.

11. The device according to claim 1 , wherein the light measurement element comprises arrays or matrices of individual measuring sensors.

12. The device according to claim 1 , wherein the ultrasound measurement element comprises arrays or matrices of individual measuring sensors.

13. A method for measurement of specific photon absorption coefficient in tissue, based on combined photo-acoustic and acousto-optic measurements;
wherein the method comprises for the photo-acoustic measurements:
radiating the tissue to be examined with a first light source;
measuring at the tissue surface an amount of sound generated within the tissue by a light of the first light source by the photo-acoustic effect;
calculating the amount of sound generated within a defined volume element from the measured amount of sound at the tissue surface;

wherein the method comprises for the acousto-optic measurements:
generating a defined sound wave pattern in the defined volume element within the tissue to be examined;
radiating the tissue to be examined with a second light source;
labelling light originating from the second light source that enters the defined volume element by means of a defined sound wave pattern in the defined volume element;
measuring an amount of labelled light exiting the tissue;

wherein the method further comprises:
deducing an amount of light originating from the first light source that actually entered the defined volume element from the amount of light generated by the second light source and from the amount of labelled light originating from the defined volume element;
deducing from the amount of light originating from the first light source that actually entered the defined volume element and the amount of sound generated in the defined volume element the specific photon absorption coefficient (p a ) of the defined volume element within the tissue.

14. The method according to claim 13 , wherein a portion of the tissue to be examined is scanned through by consecutively shifting the defined volume element through the portion of the tissue and performing after each shift measurement steps in order to define in each volume element the specific photon absorption coefficient (μ a ).

15. The method according to claim 14 , wherein a two dimensional or a three dimensional graphical representation of the tissue is composed by graphically visualizing the specific absorption coefficient (μ a ) in each volume element and placing the graphical visualization of each volume element in a two or a three dimensional location corresponding to the measured locations of the respective volume elements within the tissue to be examined.

16. The method according to claim 13 , wherein specific photon absorption coefficients (p a ) can represent specific properties of the tissue in question.

Assignees

• Steenbergen Wiendelt
• Univ Twente

Inventors

• Steenbergen Wiendelt

Classifications

• A61B5/4312

  Breast evaluation or disorder diagnosis (optical mammography A61B5/0091) · CPC title

• A61B5/0095

  by applying light and detecting acoustic waves, i.e. photoacoustic measurements · CPC title

• A61B8/0825

  for diagnosis of the breast, e.g. mammography · CPC title

• A61B5/418

  lymph vessels, ducts or nodes · CPC title

• A61B5/0097

  by applying acoustic waves and detecting light, i.e. acousto-optic measurements · CPC title