BIOLOGICAL INFORMATION IMAGING APPARATUS

• US 20110172513A1
• Filed: 11/09/2009
• Published: 07/14/2011
• Est. Priority Date: 09/12/2008
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Fukutani, Kazuhiko, Nakajima, Takao
• Application Number:
  US13/063,703
• Publication Number:
  US 20110172513A1
• Time in Patent Office: Days
• US Class Current: 600/407
• 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 5/0095 by applying light and detecting acoustic waves, i.e. photoacoustic measurements
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids
• CPC Class Codes: G01N 2201/0662 Comparing measurements on two or more paths in one sample

Abstract

The biological information imaging apparatus includes an acoustic wave detector 107 that detects an acoustic wave that is generated from a light absorber 105 and converts it to a first electrical signal; a photo-detector 110 that detects intensities of the light corresponding to a plurality of propagation distances of the light which propagates through the specimen 110 and converts it to a second electrical signal; a signal processing apparatus 111 that derives an average effective attenuation coefficient μ_eff of the specimen 110 based on the second electrical signal and derives an optical absorption coefficient μ_a of the specimen 110 based on the first electrical signal and the average effective attenuation coefficient μ_eff; and an image constructing apparatus 111 that constructs an image of the distribution of the optical absorption coefficient μ_a based on the distribution of the optical absorption coefficient μ_a.

Claims

1. A biological information imaging apparatus comprising:

an acoustic wave detector that detects an acoustic wave generated from a light absorber in a living body which absorbs a light irradiated to the living body and converts the acoustic wave to a first electrical signal;

a photo-detector that detects intensities of the light corresponding to a plurality of propagation distances of the light irradiated to the living body and propagates through the living body and converts the intensities of the light to a second electrical signal;

a signal processing apparatus that derives an average effective attenuation coefficient of the living body based on the second electrical signal and derives an optical property distribution of the living body based on the first electrical signal and the average effective attenuation coefficient; and

an image constructing apparatus that constructs an optical property distribution image of the living body based on the optical property distribution of the living body derived by the signal processing apparatus.

2. A biological information imaging apparatus according to claim 1, wherein the average effective attenuation coefficient is derived by fitting the second electrical signal to a theoretical formula of an intensity distribution of the light in the living body, which is irradiated to the living body to propagate through the living body.

3. A biological information imaging apparatus according to claim 1, wherein the optical property distribution is an optical absorption coefficient distribution of the living body.

4. A biological information imaging apparatus according to claim 2, wherein a shape of a portion of an object of measurement in the living body is fitted to a predetermined model shape to which the theoretical formula can be adapted.

5. A biological information imaging apparatus according to claim 1, wherein an irradiated position of the light and the photo-detector are disposed to face each other with the portion of the object of measurement in the living body interposed therebetween.

6. A biological information imaging apparatus according to claim 1, further comprising a light source unit having a single light source or a plurality of light sources, wherein at least light source that generates the acoustic wave that is to be converted to the first electrical signal by the acoustic wave detector among the light sources of the light source unit is a light source that generates a pulse light.

7. A biological information imaging apparatus according to claim 1, further comprising a light source unit having a plurality of light sources,

wherein the light source unit includes at least two light sources including a first light source that generates a pulse light and a second light source that generates a light having a waveform different from that of the pulse light,

wherein the acoustic wave detector is configured to convert the acoustic wave generated due to the light irradiated to the living body by the first light source to the first electrical signal, and

wherein the photo-detector is configured to convert a light irradiated to the living body by the second light source and propagates through the living body to the second electrical signal.

8. A biological information imaging apparatus according to claim 7, wherein the first light source and the second light source generate a light having the same wavelength.

9. A biological information imaging apparatus according to claim 1, wherein the photo-detector is configured to detect the intensities of the light at a plurality of the positions in the surface of the living body or in the vicinity of the surface of the living body, so that the intensities of the light corresponding to a plurality of the propagation distances of the light that is irradiated to the living body and propagates through the living body can be detected.

10. A biological information imaging apparatus according to claim 1, wherein the acoustic wave detector is configured to detect the acoustic wave at a plurality of positions in the surface of the living body or in the vicinity of the surface of the living body.

11. A biological information imaging apparatus according to claim 1, wherein the light absorber is a contrast agent that is introduced into the living body.

24. A biological information imaging apparatus according to claim 1, wherein the acoustic wave detector detects an acoustic wave generated from a light absorber in a living body which absorbs a light irradiated to a larger region than a propagation length of the light in the living body.

12. A biological information imaging method comprising:

an acoustic wave detecting process of detecting an acoustic wave generated from a light absorber in a living body which absorbs a portion of energy of a light irradiated to the living body and converting the acoustic wave to a first electrical signal;

a light detecting process of detecting intensities of the light corresponding to a plurality of propagation distances of the light irradiated to the living body and propagates through the living body and converting the intensities of the light to a second electrical signal;

an absorption density distribution calculating process of calculating an optical energy absorption density distribution that is a distribution of a product of an optical absorption coefficient of the living body and a light amount based on the first electrical signal;

an attenuation coefficient deriving process of deriving an average effective attenuation coefficient of the living body based on the second electrical signal;

an optical property distribution deriving process of deriving an optical property distribution of the living body based on the optical energy absorption density distribution calculated in the absorption density distribution calculating process and the average effective attenuation coefficient derived in the attenuation coefficient deriving process; and

an image constructing process of constructing an optical property distribution image of the living body based on the optical property distribution of the living body derived in the optical property distribution deriving process.

13. A biological information imaging method according to claim 12, wherein in the attenuation coefficient deriving process, the average effective attenuation coefficient is derived by fitting the second electrical signal to a theoretical formula of an intensity distribution of the light in the living body, which is irradiated to the living body to propagate through the living body.

14. A biological information imaging method according to claim 12, wherein the optical property distribution is an optical absorption coefficient distribution of the living body.

15. A biological information imaging method according to claim 13, wherein a shape of a portion of an object of measurement in the living body is fitted to a predetermined model shape to which the theoretical formula can be adapted.

16. A biological information imaging method according to claim 12, wherein in the light detecting process, an irradiated position of the light in the living body and a position where intensities of the light propagating through the living body corresponding to a plurality of propagation distances are detected are disposed to face each other with a portion of an object of measurement in the living body interposed therebetween.

17. A biological information imaging method according to claim 12, wherein the light irradiated to the living body in the acoustic wave detecting process is a pulse light.

18. A biological information imaging method according to claim 12,

wherein the light irradiated to the living body in the acoustic wave detecting process is a pulse light, and

wherein the light irradiated to the living body in the light detecting process is a light having a waveform different from that of the pulse light.

19. A biological information imaging method according to claim 18, wherein a wavelength of the light irradiated to the living body in the acoustic wave detecting process and a wavelength of the light irradiated to the living body in the light detecting process are the same.

20. A biological information imaging method according to claim 12, wherein in the light detecting process, the intensities of the light are detected at a plurality of the positions in the surface of the living body or in the vicinity of the surface of the living body, so that the intensities of the light corresponding to a plurality of the propagation distances of the light irradiated to the living body and propagates through the living body can be detected.

21. A biological information imaging method according to claim 12, wherein in the acoustic wave detecting process, the acoustic wave is detected at a plurality of positions in the surface of the living body or in the vicinity of the surface of the living body.

22. A biological information imaging method according to claim 12, wherein the light absorber is a contrast agent introduced into the living body.

23. A program which executes on a computer at least one of the absorption density distribution calculating process, the attenuation coefficient deriving process, the optical property distribution deriving process, and the image constructing process in the biological information imaging method according to claim 12.

25. A biological information imaging method according to claim 12, wherein the light irradiated to the living body in the acoustic wave detecting process is a light irradiated to a larger region than a propagation length of the light in the living body.