Specimen information acquisition apparatus

Patent metadata

Field	Value
Publication number	US-10321894-B2
Application number	US-201214119411-A
Country	US
Kind code	B2
Filing date	May 11, 2012
Priority date	May 26, 2011
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

Stepwise pressurization in which, after pressure is instantaneously increased to a certain pressure value, the certain pressure value is kept for a certain time period is performed to measure the variation with time of strain distribution in the specimen and to calculate a stress from strain distribution at a saturation measurement time when the effect of the viscosity of a viscoelasticity measurement reference layer is saturated, thereby evaluating the modulus of elasticity and the coefficient of viscosity of a body tissue.

First claim

The invention claimed is:

1. A specimen information acquisition apparatus that transmits elastic waves to a specimen and receives the elastic waves reflected in the specimen to acquire information in the specimen, the specimen information acquisition apparatus comprising:
a probe including a transducer that converts the received elastic waves into an electrical signal;
a measurement unit that measures a strain in the specimen and a strain of a reference layer provided between the transducer and the specimen when pressure is applied on the specimen and the reference layer by using the electrical signal, the reference layer having a known modulus of elasticity;
a pressure applying unit that applies pressure on the specimen via the reference layer in a stepwise manner with respect to time by pressing the reference layer against the specimen; and
a calculation unit that calculates a coefficient of viscosity and a modulus of elasticity of the specimen by using the modulus of elasticity of the reference layer, a variation in the strain in the specimen, and a saturation value of the strain of the reference layer after the pressure applying unit applies the pressure in the stepwise manner.

2. The specimen information acquisition apparatus according to claim 1 ,
wherein the pressure applying unit includes a compression member,
wherein the reference layer is positioned on a side of the compression member opposing the specimen so as to be arranged between the specimen and the compression member, and
wherein the transducer is positioned on a side opposite to the side of the compression member opposing the specimen so as to transmit and receive the elastic waves to and from the specimen via the compression member and the reference layer.

3. The specimen information acquisition apparatus according to claim 2 , further comprising:
a scanner that moves the probe along the compression member and relative to the specimen,
wherein the pressure applying unit controls the pressure so that the compression member performs stepwise pressurization in which different pressures are applied on the specimen and the reference layer at each position of the transducer to be scanned,
wherein the measurement unit measures strain distribution in the specimen and strain distribution of the reference layer on the basis of the stepwise pressurization, and
wherein the calculation unit calculates coefficient-of-viscosity distribution of the specimen by using the modulus of elasticity of the reference layer, the strain distribution in the specimen, and distribution of the saturation value of the strain of the reference layer.

4. The specimen information acquisition apparatus according to claim 1 ,
wherein the pressure applying unit includes a tension band that holds the specimen, and
wherein the pressure applying unit controls a tension of the tension band to control the pressure to be applied on the specimen and the reference layer.

5. The specimen information acquisition apparatus according to claim 1 , wherein the reference layer has a thickness of 0.1 mm to 50 mm.

6. The specimen information acquisition apparatus according to claim 5 , wherein the reference layer has a thickness of 1 mm to 10 mm.

7. The specimen information acquisition apparatus according to claim 1 , further comprising a processor that obtains a tomographic image of the specimen based on the elastic waves reflected in the specimen.

8. The specimen information acquisition apparatus according to claim 7 , wherein the processor causes a display to display the tomographic image and an image of viscoelasticity of the specimen.

9. A specimen information acquisition method comprising:
receiving, using a probe including a transducer, elastic waves transmitted to and reflected in the specimen via a reference layer having a known modulus of elasticity;
converting, using the transducer, the received elastic waves into an electrical signal;
measuring, using a measurement unit, a strain in the specimen and a strain of the reference layer provided between the transducer and the specimen when pressure is applied on the specimen and the reference layer by using the electrical signal;
applying pressure on the specimen via the reference layer in a stepwise manner with respect to time by pressing the reference layer against the specimen; and
calculating, using a processor, a coefficient of viscosity and a modulus of elasticity of the specimen by using the modulus of elasticity of the reference layer, a variation in the strain in the specimen, and a saturation value of the strain of the reference layer, after the pressure is applied in the stepwise manner.

10. The specimen information acquisition method according to claim 9 , further comprising:
positioning the reference layer on a side of the compression member opposing the specimen so as to be arranged between the specimen and the compression member,
wherein the conversion transducer is positioned on a side opposite to the side of the compression member opposing the specimen so as to transmit and receive the elastic waves to and from the specimen via the compression member and the reference layer.

11. The specimen information acquisition method according to claim 10 , further comprising:
moving the probe along the compression member and relative to the specimen,
controlling the pressure so that the compression member performs stepwise pressurization in which different pressures are applied on the specimen and the reference layer at each position of the transducer to be scanned,
measuring strain distribution in the specimen and strain distribution of the reference layer on the basis of the stepwise pressurization, and
calculating coefficient-of-viscosity distribution of the specimen by using the modulus of elasticity of the reference layer, the strain distribution in the specimen, and distribution of the saturation value of the strain of the reference layer.

12. The specimen information acquisition method according to claim 9 , further comprising obtaining a tomographic image of the specimen based on the elastic waves reflected in the specimen.

13. The specimen information acquisition method according to claim 12 , further comprising causing a display to display the tomographic image and an image of viscoelasticity of the specimen.

Assignees

• Oikawa Katsuya
• Yamakawa Makoto
• Shiina Tsuyoshi
• Canon Kk

Inventors

• Oikawa Katsuya
• Yamakawa Makoto
• Shiina Tsuyoshi

Classifications

• G01S7/52042

  determining elastic properties of the propagation medium or of the reflective target (diagnostic techniques involving the measurement of strain A61B8/485) · CPC title

• A61B8/485 Primary

  involving measuring strain or elastic properties · CPC title

• A61B8/0858

  involving measuring tissue layers, e.g. skin, interfaces · CPC title

• A61B8/0825

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

• A61B8/54

  Control of the diagnostic device · CPC title