JPH0698891A - Optical diagnostic apparatus - Google Patents

Abstract

PURPOSE:To achieve clear identification of tissues of a specimen while observing changes in condition of the tissues of the specimen by determining a color CT image of the specimen moving turning in real time. CONSTITUTION:A laser beam containing a plurality of wavelengths is outputted from a laser oscillation means 20 and branched in two directions. On part of the beam is made to irradiate a specimen 2 and the other part thereof is modulated by a frequency. The laser beam transmitted through the specimen 2 is combined with the laser beam modulated by the frequency and the combined laser beam is converted into electrical signals in terms of the wavelengths by a light detection means 21. A color tomographic image of the specimen 2 is determined by an image data processing means 28 based on the electrical signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical optical diagnostic apparatus such as an optical CT apparatus, and more particularly to an optimal optical diagnostic apparatus for discriminating a tissue of an object to be diagnosed.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of an optical CT apparatus. A subject 2 is placed on the pulse stage 1. The pulse stage 1 is rotated by a drive device 3 in steps of a predetermined angle.

A single wavelength laser oscillator 4 is also provided. The laser beam output from the laser oscillator 4 is split by the beam splitter 5 into a signal laser beam q and a reference laser beam g. Of these, the signal laser beam q is applied to the subject 2, passes through the subject 2, and reaches the beam splitter 6. In this case, the tissue of the subject 2 has a characteristic of absorbing a specific wavelength. Therefore, when the signal laser beam q passes through the subject 2, the wavelength component corresponding to the tissue is absorbed.

On the other hand, the reference laser beam g is reflected by the mirror 7 and guided to the acousto-optical element 8.
Is frequency-modulated by, reflected by the mirror 9 and guided to the beam splitter 6.

In the beam splitter 6, the signal laser beam qa transmitted through the subject 2 and the frequency-modulated reference laser beam ga are combined and guided to the detector 10. The detector 10 converts the incident combined beam qg into an electric signal according to the intensity of the signal laser beam qa, and a subsequent amplifier 11 amplifies the converted electric signal and sends it to the frequency separator 12.

The frequency separator 12 separates a necessary frequency band component from the input electric signal and transfers it to the image data processing device 13. The image data processing device 13 processes the received electric signal as image data. A tomographic image of the subject 2, that is, a CT image is created.

The controller 14 controls the driving of the driving device 3 to rotate the pulse stage 1 and sends information on the rotation to the data processing device 13.

However, in such an optical CT apparatus, the subject 2 is irradiated with the laser beam q having a single wavelength, and the CT image is created by the transmission intensity thereof, so that each tissue of the subject 2 is clearly shown. It is difficult to distinguish and form a CT image. That is, since each tissue of the subject 2 has a characteristic of absorbing a specific wavelength in the tissue, in order to distinguish each tissue, it is necessary to transmit a laser beam of each wavelength corresponding thereto. For example, Figure 4 shows the human skin
It shows the relationship between the absorption and scattering coefficients of dermis, melanin, and hemoglobin and the wavelength, but at a wavelength of 600 nm, it is difficult to distinguish between hemoglobin and the epidermis, and for other tissues, if there is no other wavelength. Can not. Further, the obtained CT image is of a single color, and a plurality of data are separately required to clearly distinguish each tissue by its density. Further, if the CT image is colorized, each tissue can be distinguished, but this requires complicated image data processing, and the processing time is long, and the CT image of the moving subject 2 is real time. It will be difficult to display.

[0009]

As described above, the subject 2
It is difficult to clearly distinguish each of the tissues to form a CT image, and it is difficult to display the CT image in color in real time.

Therefore, the present invention is an optical diagnostic apparatus capable of obtaining a color CT image of a subject rotating and moving in real time to clearly distinguish each tissue of the subject and observing the state change of the tissue of the subject. The purpose is to provide.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a laser beam is branched into two directions, one of the laser beams is applied to a subject, the other laser beam is frequency-modulated, and the laser beam is transmitted through the subject. In an optical diagnostic apparatus that obtains a tomographic image of a subject based on the intensity of a combined beam of a laser beam and a frequency-modulated laser beam, a laser oscillating unit that outputs a laser beam having a plurality of wavelength components, and receives the combined beam. An optical detection unit that converts each electric signal corresponding to the intensity of each wavelength included in the combined beam, and an image data processing unit that obtains a color tomographic image of the subject based on each electric signal from the optical detection unit. An optical diagnostic apparatus is provided to try to achieve the above object.

[0012]

By providing such means, a laser beam containing a plurality of wavelengths is output from the laser oscillating means and branched in two directions, one of which is irradiated on the subject and the other of which is frequency-modulated. The laser beam that has passed through the subject is combined with the frequency-modulated laser beam, and then converted into electrical signals for each wavelength by the light detection means. Then, a color tomographic image of the subject is obtained by the image data processing means based on these electric signals.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those in FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a block diagram of an optical CT apparatus. The laser oscillator 20 has three different wavelengths, for example, red,
It has a function of outputting a laser beam containing each wavelength of blue and green.

On the other hand, a light detecting means 21 is arranged at a position facing the pulse stage 1 from the laser oscillator 20 via the beam splitters 5 and 6. The light detecting means 21 receives the combined laser beam QG of the signal laser beam Qa that has passed through the subject 2 and the frequency-modulated reference laser beam Ga, and each wavelength included in the combined laser beam QG, that is, red, It has a function of converting each wavelength of blue and green into each electric signal according to its intensity.

A specific structure will be described with reference to FIG. 2. A diffraction grating 22 is arranged on the optical path of the combined laser beam QG.
G is diffracted into laser beams a, b, and c in respective directions unique to each wavelength. A photodetector 23 is arranged on the optical paths of these laser beams a, b, and c.

The photodetector 23 includes a lens 24, a micro channel plate (MCP) 25, and a parallel plate electrode 2.
6 and the CCD camera 27 are arranged.
Of these, the parallel plate electrode 26 is the electrode 26a, 26b.
Are opposed to each other, and a high voltage is applied between the electrodes 26a and 26b. These electrodes 26a, 26
When the pulse stage 1 makes one rotation, the photoelectrons incident on the CCD camera 27 are indicated by the arrow (a).
It changes to the value swept in the direction.

Therefore, in the photodetector 23, the laser beams a, b and c are guided to different positions h1, h2 and h3 on the microchannel plate 25 through the lens 24 and converted into photoelectrons by the microchannel plate 25. And leads to the parallel plate electrode 26. And
The parallel plate electrode 26 controls the traveling direction of photoelectrons, and C
The CD camera 27 is guided to each predetermined position f1, f2, f3.

Here, the photoelectrons incident on the respective positions f1, f2, f3 have information on the absorption coefficient of the subject 2 at the respective wavelengths of red, blue and green.
The CCD camera 27 detects the photoelectrons incident on the positions f1, f2, and f3 and converts them into electric signals corresponding to the photoelectrons and outputs them.

The image data processing device 28 has a function of inputting each electric signal from the CCD camera 27 and processing the image data to obtain a color CT image of the subject 2.

The control device 29 has a function of driving and controlling the driving device 3 to rotate the pulse stage 1 and sending information of this rotation to the image data processing device 28.

Next, the operation of the device configured as described above will be described.

The laser oscillator 20 outputs a laser beam containing each wavelength of red, blue and green. This laser beam is converted into a signal laser beam Q by the beam splitter 5.
And a reference laser beam S. Of these, the signal laser beam Q is applied to the subject 2, passes through the subject 2, and reaches the beam splitter 6. In this case, the tissue of the subject 2 has the characteristic of absorbing the specific wavelength as shown in FIG. 4 as described above. Therefore, when the signal laser beam Q passes through the subject 2, each wavelength component corresponding to each tissue is absorbed.

On the other hand, the reference laser beam S is reflected by the mirror 7 and guided to the acousto-optic element 8.
Is frequency-modulated by, reflected by the mirror 9 and guided to the beam splitter 6.

The beam splitter 6 combines the signal laser beam Qa that has passed through the subject 2 and the frequency-modulated reference laser beam Sa. The combined laser beam QS enters the diffraction grating 22.

The diffraction grating 22 diffracts the incident combined laser beam QS into respective directions peculiar to the respective wavelengths of red, blue and green, and diffracts the respective laser beams a, b and c, and the photodetector 23.
Lead to.

The photodetector 23 is provided with each laser beam a,
b and c are led to different positions h1, h2 and h3 on the micro channel plate 25 through the lens 24, converted into photoelectrons by the micro channel plate 25 and led to the parallel plate electrode 26.

Each electrode 26a, 2 of this parallel plate electrode 26
A high voltage that changes according to the rotation of the pulse stage 1 is applied between 6b, and the traveling direction of the photoelectrons incident between these electrodes 26a and 26b is controlled according to the applied voltage, so that the CCD camera 27 Each position f1, f2, f3 of
It is swept in the direction of the arrow (a) passing through. For example, each electrode 2
The applied voltage between 6a and 26b changes in synchronization with the rotation angle of the pulse stage 1, and when the pulse stage 1 makes one rotation, photoelectrons are swept in the direction of arrow (a).

The photoelectrons incident on these positions f1, f2, f3 have information on the absorption coefficient of the subject 2 at the respective wavelengths of red, blue and green, and the CCD camera 27 has these positions f1, f2. , F3, each electric signal corresponding to the intensity of the incident photoelectrons is output.

These electric signals are sent to the image data processing device 28.
The image data processing device 28 performs image processing on the basis of each electric signal having each wavelength component of red, blue, and green to create a color CT image of the subject 2. In this case, the image data processing device 28 indicates that each electric signal is red,
Since each wavelength component of blue and green is included, a color CT image can be obtained with a small amount of data processing.

As described above, in the above-described embodiment, the subject 2 is irradiated with the laser beams having the respective wavelength components of red, blue and green, and the signal laser beam Qa transmitted through the subject 2 and the frequency-modulated laser are transmitted. Combining with beam Ga,
Since the combined laser beam QG is converted into electrical signals for each wavelength of red, blue and green, and a color CT image of the subject 2 is obtained based on these electrical signals, the CT image of the subject 2 is obtained. It can be expressed in color, whereby each tissue of the subject 2 can be easily represented by each different color, and each tissue can be clearly distinguished.

Therefore, changes in the state of each tissue of the subject 2 can be observed, and, for example, a normal tissue and an abnormal tissue can be easily diagnosed.

Since color CT images are created from the intensities of the red, blue and green wavelengths, image processing is easy and the color CT of the subject 2 moving in real time is easy.
Can create images.

The present invention is not limited to the above-mentioned one embodiment, and may be modified within the scope of the invention. For example, the laser oscillator 20 may include each laser oscillator that outputs a laser beam of each wavelength, and guide each laser beam output from these laser oscillators to the same optical path. In this case, the wavelength of each laser oscillator is
It may be changed according to the diagnosis or observation of the subject.

Instead of the diffraction grating 22, an element prism for wavelength decomposition may be used.

Further, it is not limited to the CCD camera 27 as long as it can detect photoelectrons on a plane and convert them into electric signals.

The photodetector 2 is not limited to the color CT image.
3 from each electric signal of each wavelength component obtained by 3, for example, only the red electric signal, each CT of each tissue according to the wavelength
You may make it obtain an image.

Further, the wavelength components output from the laser oscillator are not limited to red, blue and green, and may be other wavelength components.

[0039]

As described in detail above, according to the present invention, it is possible to clearly distinguish each tissue of a subject by obtaining a color CT image of the subject rotating and moving in real time, and to identify the tissue of the subject. It is possible to provide an optical diagnostic device capable of observing state changes and the like.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an optical diagnostic apparatus according to the present invention.

FIG. 2 is a specific configuration diagram of a light detection unit in the same device.

FIG. 3 is a block diagram of a conventional device.

FIG. 4 is a diagram showing a relationship between absorption and scattering coefficients and wavelength.

[Explanation of symbols]

1 ... Pulse stage, 2 ... Subject, 3 ... Driving device, 5,
6 ... Beam splitter, 7, 9 ... Mirror, 8 ... Acousto-optic element, 20 ... Laser oscillator, 21 ... Photodetection means, 22 ...
Diffraction grating, 23 ... Photodetector, 28 ... Image data processing device, 29 ... Control device.

Claims (1)

[Claims] 1. A laser beam is branched into two directions, one of the laser beams is applied to a subject, the other laser beam is frequency-modulated, and the laser beam that has passed through the subject and the frequency-modulated laser. In an optical diagnostic apparatus that obtains a tomographic image of the subject based on the intensity of a combined beam with a beam, a laser oscillating unit that outputs a laser beam having a plurality of wavelength components, and the combined beam is received to form a combined beam. The light detecting means is provided for converting the electric signals corresponding to the intensities of the respective wavelengths contained therein, and the image data processing means for obtaining a color tomographic image of the subject based on the electric signals from the light detecting means. An optical diagnostic device characterized by the above.