MEASURING APPARATUS

• US 20110270071A1
• Filed: 04/14/2011
• Published: 11/03/2011
• Est. Priority Date: 04/28/2010
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Furukawa, Yukio
• Application Number:
  US13/086,530
• Publication Number:
  US 20110270071A1
• Time in Patent Office: Days
• US Class Current: 600/407
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/4312 Breast evaluation or disorder diagnosis A61B5/0091 takes precedence
• CPC Class Codes: A61B 8/0825 for diagnosis of the breast, e.g. mammography

Abstract

In photoacoustic imaging, in cases where an emitted light amount and a beam pattern of a laser vary according to variation with time and external factors, and cases where the wavelength and the repetition rate of the laser vary, there is a danger that a light fluence of light applied to tissue become too strong. A unit is provided for measuring a distribution of light fluence of light applied to the tissue. A measuring apparatus is provided that controls output of a laser source such that the measured light fluence should not exceed the maximum permissible exposure to the tissue. Accordingly, highly safe photoacoustic imaging to the tissue can be realized.

Claims

1. A measuring apparatus comprising a laser source generating light, a unit for light illumination illuminating tissue with the light, and an acoustic wave detector detecting an acoustic wave generated by the light applied to the tissue, further comprising

a unit for detecting optical energy that detects an light fluence of the light onto the tissue,

wherein an emitted light amount from the laser source is controlled such that the light fluence detected by the unit for detecting optical energy does not exceed a maximum permissible exposure.

2. The measuring apparatus according to claim 1, wherein at least one of the unit for light illumination and the unit for detecting optical energy is provided at a first moving mechanism capable of two-dimensionally moving, and is capable of measuring a distribution of light fluence of the light applied to the tissue by two-dimensional scanning.

3. The measuring apparatus according to claim 1, further comprising a controlling unit that controls the emitted light amount of the laser source such that the light fluence detected by the unit for detecting optical energy does not exceed the maximum permissible exposure.

4. The measuring apparatus according to claim 1,

wherein the unit for detecting optical energy includes a group of optical energy detectors where a plurality of optical energy detectors are arranged in a two-dimensionally planar manner, and

the group of optical energy detectors measures a distribution of light fluence of the light applied to the tissue.

5. The measuring apparatus according to claim 1,

wherein the unit for detecting optical energy is arranged in the apparatus, and

the unit for light illumination is arranged in a second moving mechanism, and capable of switching a state of illuminating the tissue with the light and a state of illuminating the unit for detecting optical energy with the light by moving the second moving mechanism.

6. The measuring apparatus according to claim 5, wherein the second moving mechanism is used commonly with the first moving mechanism.

7. The measuring apparatus according to claim 1, wherein the unit for detecting optical energy is detachable, the detachable unit for detecting optical energy is arranged at a position for holding the tissue, and the light fluence is detected.

8. The measuring apparatus according to claim 3, wherein the unit for detecting optical energy has a function of detecting a repetition rate of illumination light, and the controlling unit controls the emitted light amount from the laser source according to the light fluence and the repetition rate detected by the unit for detecting optical energy.

9. The measuring apparatus according to claim 3, further comprising a unit for measuring wavelength that measures a wavelength of emitted light from the laser source, wherein the controlling unit controls the emitted light amount from the laser source according to the wavelength measured by the unit for measuring wavelength.

10. The measuring apparatus according to claim 9, wherein the unit for measuring wavelength is arranged in a casing of the laser source.

11. The measuring apparatus according to claim 1, wherein the unit for detecting optical energy includes an aperture provided with a window having a size specified by a laser safety standard.

12. The measuring apparatus according to claim 1, further comprising at least one supporting plate contacting with the tissue for holding the tissue.

13. The measuring apparatus according to claim 1, wherein the unit for light illumination and the acoustic wave detector are arranged on a side opposite to the tissue through the supporting plate, the unit for light illumination includes an optical system causing light to propagate obliquely through the supporting plate and illuminating a front of the acoustic wave detector with the light, and the unit for detecting optical energy includes an optical part optically matched with the supporting plate.

14. The measuring apparatus according to claim 13, wherein the optical part is a prism.

15. The measuring apparatus according to claim 13, wherein the optical part is provided with an aperture having a size specified by a laser safety standard on a surface opposed to the supporting plate.