PHOTOACOUSTIC APPARATUS

• US 20110106478A1
• Filed: 10/20/2010
• Published: 05/05/2011
• Est. Priority Date: 10/29/2009
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Someda, Yasuhiro
• Granted Patent: US 9,226,662 B2
• Time in Patent Office: Days
• US Class Current: 702/104
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids

Abstract

In a photoacoustic apparatus, a light source irradiates an inspection target with pulsed light; a detector detects acoustic waves generated in the inspection target due to interaction of the pulsed light with the inspection target, and outputs detection signals corresponding to the detected acoustic waves; a light-quantity measurement unit measures the quantity of the light output from the light source; and a signal processor obtains information on an inside of the inspection target by using the detection signals output from the detector. The signal processor also corrects intensities of the detection signals so as to suppress variations in intensities of the detection signals caused by a temporal change in the quantity of the light.

Claims

1. A photoacoustic apparatus comprising:

a light source which irradiates an inspection target with pulsed light;

a detector which detects acoustic waves generated in the inspection target due to interaction of the pulsed light with the inspection target, and outputs detection signals corresponding to the detected acoustic waves;

a light-quantity measurement unit which measures a quantity of light output from the light source; and

a signal processor which processes the detection signals output by the detector so as to obtain information on an inside of the inspection target,

wherein the signal processor includes a signal correction unit which corrects intensities of the detection signals in accordance with a temporal change in the quantity of light measured by the light-quantity measurement unit so that variations in the intensities of the detection signals are suppressed.

2. A photoacoustic apparatus according to claim 1, further comprising:

a correction-amount determination unit which determines correction amounts for correcting the detection signals in accordance with the temporal change of the quantity of light measured by the light-quantity measurement unit,

wherein the signal correction unit corrects the intensities of the detection signals using the correction amounts determined by the correction-amount determination unit.

3. The photoacoustic apparatus according to claim 2, further comprising:

a memory which stores the quantity of light measured by the light-quantity measurement unit,

wherein the correction-amount determination unit reads data regarding the temporal change in the quantity of light stored in the memory.

4. The photoacoustic apparatus according to claim 1,

wherein the signal processor includes an A/D converter which converts the detection signals which are analog signals obtained by the detector into digital signals, and

the signal correction unit performs the correction on the digital signals.

5. The photoacoustic apparatus according to claim 1,

wherein the signal processor further includes an image reconstruction processor which processes the detection signals so as to obtain the information on the inside of the inspection target and which performs image reconstruction, and

the signal correction unit performs the correction on digital data which has been subjected to the image reconstruction.

6. The photoacoustic apparatus according to claim 2,

wherein the signal processor determines correction amounts for the detection signals in accordance with an attenuation coefficient of light inside the inspection target.

7. The photoacoustic apparatus according to claim 6,

wherein the correction-amount determination unit determines the correction amounts for the detection signals taking irradiation-light-quantity distribution on a surface of the inspection target into consideration.

8. The photoacoustic apparatus according to claim 6, wherein

the light source includes a plurality of light sources;

and

the light-quantity measurement unit includes a plurality of light-quantity measurement units which measure quantities of light beams output from the light sources,

wherein the correction-amount determination unit determines the correction amounts for correcting the detection signals in accordance with temporal changes in the light quantities measured by the light-quantity measurement units.

9. The photoacoustic apparatus according to claim 1, further comprising:

plates which press and fix the inspection target from opposite sides of the inspection target; and

a movement mechanism which moves a portion in which light output from the light source is incident on, the detector, and the light-quantity measurement unit along the plates for scanning.

10. A computer-readable medium storing a program which causes a computer to execute the steps of:

obtaining detection signals of acoustic waves generated in an inspection target by irradiating the inspection target with pulsed light;

correcting intensities of the detection signals in accordance with a temporal change in a quantity of the pulsed light so that variations in the intensities of the detection signals are suppressed; and

obtaining information on an inside of the inspection target using the corrected detection signals.