Apparatus for imaging a blood vessel

• US 6,522,911 B1
• Filed: 11/22/1999
• Issued: 02/18/2003
• Est. Priority Date: 11/20/1998
• Status: Expired due to Fees

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Sato, Tomoo, Toida, Masahiro
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): MANTIS MERCADER, ELENI M
• Application Number:
  US09/444,514
• Time in Patent Office: 1,184 Days
• Field of Search: 600/473, 600/475, 600/476, 600/322, 600/316, 600/310, 600/317, 600/323, 600/326, 600/330, 600/335, 600/336, 600/407, 356/319, 356/450, 356/484, 356/485
• US Class Current: 600/473
• 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 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance

Abstract

A first measuring light beam of wavelength λ₁ equal to a wavelength at the isosbestic point between oxyhemoglobin and deoxyhemoglobin and a second measuring light beam of wavelength λ₂ differing from the first measuring light beam are incident on the same part of a subject such as a human finger and scan the subject by using an X-Y stage movable in X and Y directions. The first measuring light beam branches into two light beams. One of the two light beams is subjected to a frequency shift by a frequency shifter, while the other is transmitted through the subject. Thereafter, the two light beams are synthesized and a beat component of the synthesized first measuring light beam is detected by a first signal detection section. The first signal detection section outputs a first beat-component detection signal. For the second measuring light beam, a second beat-component detection signal is output in the same manner as the first measuring light beam. A personal computer generates an image signal based on a value of the second beat-component detection signal normalized by the first beat-component detection signal.

Claims

1. A blood vessel imaging apparatus comprising:

light source means for emitting a first measuring light beam and a second measuring light beam differing from said first measuring light beam, said first measuring light beam having a wavelength equal to a wavelength at an isosbestic point between oxyhemoglobin and deoxyhemoglobin in the blood of a living organism;

an incident optics system for causing said first measuring light beam and said second measuring light beam to be incident on the same part of said living organism;

scanner means for scanning said living organism with said first measuring light beam and said second measuring light beam;

a first optical heterodyne detection system equipped with a first optics system for synthesizing said first measuring light beam and a branched first measuring light beam transmitted through said living organism;

a first frequency shifter for giving a difference in frequency between said first measuring light beam and said branched first measuring light beam; and

first detection means for detecting a first beat component of said synthesized first measuring light beam and outputting a first beat component detection signal;

a second optical heterodyne detection system equipped with a second optics system for synthesizing said second measuring light beam and a branched second measuring light beam transmitted through said living organism;

a second frequency shifter for giving a difference in frequency between said second measuring light beam and said branched second measuring light beam; and

second detection means for detecting a second beat component of said synthesized second measuring light beam and outputting a second beat component detection signal; and

image signal generation means for generating an image signal, based on a value of said second beat component detection signal normalized by said first beat component detection signal.

2. The blood vessel imaging apparatus as set forth in claim 1, wherein

said light source means emits a light beam of wavelength λ ₁ as said first measuring light beam and emits a light beam of wavelength λ

₂ as said second measuring light beam; and

when it is assumed that a value of a beat component detection signal related to said measuring light beam of wavelength λ

₁ is Iλ

₁ and a beat component detection signal related to said measuring light beam of wavelength λ

₂ is Iλ

₂, said image signal generation means generates said image signal, based on a value of log(Iλ

₂/Iλ

₁).

3. The blood vessel imaging apparatus as set forth in claim 2, wherein said wavelength λ

₁ is 805 nm and said wavelength λ

₂ is 760 nm.

4. The blood vessel imaging apparatus as set forth in claim 2, wherein said wavelength λ

₁ is 805 nm and said wavelength λ

₂ is 930 nm.

5. The blood vessel imaging apparatus as set forth in claim 1, wherein

said light source means emits a light beam of wavelength λ

₁ as said first measuring light beam and emits a light beam of wavelength λ

₂ and a light beam of wavelength λ

₃ as said second measuring light beam; and

when a value of a beat component detection signal related to said measuring light beam of wavelength λ

₁ is assumed to be Iλ

₁, a beat component detection signal related to said measuring light beam of wavelength λ

₂ to be Iλ

₂, and a beat component detection signal related to said measuring light beam of wavelength λ

₃ to be Iλ

₃, said image signal generation means generates said image signal, based on a difference between a value of log(Iλ

₂/Iλ

₁) and a value of log(Iλ

₃/Iλ

₁).

6. The blood vessel imaging apparatus as set forth in claim 5, wherein said wavelength λ

₁ is 805 nm, said wavelength λ

₂ is 760 nm, and said wavelength λ

₃ is 930 nm.

7. The blood vessel imaging apparatus as set forth in claim 1, further comprising synchronous detection means for detecting a pulse wave of the artery of said living organism and performing the beat component detection of said first and second measuring light beams in synchronization with a predetermined phase of said pulse wave.

8. The blood vessel imaging apparatus as set forth in claim 2, further comprising synchronous detection means for detecting a pulse wave of the artery of said living organism and performing the beat component detection of said first and second measuring light beams in synchronization with a predetermined phase of said pulse wave.

9. The blood vessel imaging apparatus as set forth in claim 3, further comprising synchronous detection means for detecting a pulse wave of the artery of said living organism and performing the beat component detection of said first and second measuring light beams in synchronization with a predetermined phase of said pulse wave.

10. The blood vessel imaging apparatus as set forth in claim 4, further comprising synchronous detection means for detecting a pulse wave of the artery of said living organism and performing the beat component detection of said first and second measuring light beams in synchronization with a predetermined phase of said pulse wave.

11. The blood vessel imaging apparatus as set forth in claim 5, further comprising synchronous detection means for detecting a pulse wave of the artery of said living organism and performing the beat component detection of said first and second measuring light beams in synchronization with a predetermined phase of said pulse wave.

12. The blood vessel imaging apparatus as set forth in claim 6, further comprising synchronous detection means for detecting a pulse wave of the artery of said living organism and performing the beat component detection of said first and second measuring light beams in synchronization with a predetermined phase of said pulse wave.

13. The blood vessel imaging apparatus as set forth in claim 2, wherein if log (Iλ

₂/Iλ

₁) is a positive value, said image signal generation means generates said image signal that produces an image showing an arterial part.

14. The blood vessel imaging apparatus as set forth in claim 2, wherein if log (Iλ

₂/Iλ

₁) is a negative value, said image signal generation means generates said image signal that produces an image showing a venous part.

15. The blood vessel imaging apparatus as set forth in claim 1, wherein if said first measuring light beam and said second measuring light beam are transmitted through a venous part, a value of said second beat component detection signal decreases.

16. The blood vessel imaging apparatus as set forth in claim 1, wherein if said first measuring light beam and said second measuring light beam are transmitted through an arterial part, a value of said second beat component detection signal increases.