JPH05184580A - Optical ct device - Google Patents

Abstract

PURPOSE:To obtain optical CT image data without rotating a body to be examined. CONSTITUTION:A body 3 to be examined is covered with a cover body 20, and gas in the cover body at the time when the body to be examined is covered with this cover body is exhausted by an exhaust means 23. As a result, atmospheric pressure in the inside of the cover body falls and a shape of the body to be examined is regulated. In such a state, by at least one pair of light emitting/receiving means 26, 27 provided in the inside of the cover body, the body to be examined is irradiated with a monochromatic laser light, and also, in such a state, the light emitting/receiving means are rotated integrally centering around the body to be examined by a rotating mechanism. Subsequently, at every rotation angle, a measuring laser light which transmits through the body to be examined and a reference laser light are superposed, and from this superposed laser light, an optical CT image of the body to be examined is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical CT apparatus used for diagnosing breast cancer and the like.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram of an optical CT apparatus using an optical heterodyne detection method. The monochromatic laser beam output from the laser oscillator 1 is split into two directions by the beam splitter 2, and one of the laser beams is a subject 3 such as a chest.
To reach the beam splitter 4 as a measurement laser beam. Here, the subject 3 is placed on the turntable 5 and is rotated by the turntable 5 at a predetermined angle. As a result, the laser light transmitted through the subject 3 is different from the subject 3 by a predetermined angle. At the same time, the other laser beam split by the beam splitter 2 is reflected by the mirror 6 and enters the acoustooptic device 7.
This acousto-optic element 7 frequency-modulates the laser light and outputs it as reference laser light, and this reference laser light is reflected by a mirror 8 and reaches the beam splitter 4. The beam splitter 4 superimposes the measurement laser light and the reference laser light on each other and sends the superposed light to an optical detector 9.
Outputs an electric signal according to the intensity of the received laser beam. Then, the photodetector 9 outputs an electric signal for each rotation angle of the rotary table 5. The optical CT image processing apparatus 10 receives the electrical signal for each rotation angle output from the photodetector 9 and performs image processing to obtain optical CT image data.

However, in the above-mentioned apparatus, in order to diagnose breast cancer, for example, the human body must be placed on the turntable 5 and rotated. For this reason, the size of the rotary table 5 becomes large, and it becomes very difficult to rotate the chest as the subject 3 as a center.

[0004]

As described above, the living body must be placed on the turntable and rotated, and it is very difficult to rotate the subject around the subject. Therefore, an object of the present invention is to provide an optical CT device that can obtain optical CT image data without rotating the subject.

[0005]

The present invention irradiates a subject with monochromatic laser light and superimposes the measurement laser light transmitted through the subject and the reference laser light whose frequency is modulated on the laser light. Optical CT of the subject from the superimposed laser light
In an optical CT apparatus for obtaining an image, a cover covering a subject,
Exhaust means for discharging gas inside the cover when the cover is covered with the cover, and laser light that is arranged inside the cover to transmit laser light to irradiate the target and to transmit the measured laser light that has passed through the target. An optical CT for achieving the above object, which is provided with at least one pair of light emitting and receiving means for receiving light and a rotating mechanism for integrally rotating the light emitting and receiving means around the subject.
It is a device.

[0006]

By providing such means, the object is covered with the cover, and the gas in the cover when the object is covered with the cover is exhausted by the exhaust means. As a result, the atmospheric pressure inside the cover is lowered and the shape of the subject is adjusted. In this state, the subject is irradiated with monochromatic laser light by at least one pair of light emitting / receiving means provided inside the cover, and in this state, the light emitting / receiving means is integrated around the subject by the rotating mechanism. Rotate. Then, the measurement laser light transmitted through the subject and the reference laser light are superposed at each rotation angle, and an optical CT image of the subject is obtained from the superposed laser light.

[0007]

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. 9 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows an optical C using the optical heterodyne detection method.
It is a block diagram of a T device. The device is provided with a chest pad 20 as a cover. The chest pad 20 is formed in a hemispherical shape as shown in the sectional view of FIG. 2, and a ball bearing 21 which is a rotating mechanism is provided at the edge thereof. As a result, the chest pad 20 becomes rotatable in the arrow (a) direction by the ball bearing 21. As shown in FIG. 3, the ball bearing 21 includes annular bearings 21a and 21b formed of plastic and a magnetic ball 21c inserted between the bearings 21a and 21b.
And a magnetic material 21d interposed between the bearings 21a and 21b and the magnet ball 21c.

An exhaust pump 23 is connected to the upper portion of the chest pad 20 via an exhaust pipe 22. The exhaust pump 23 exhausts the gas in the space inside the chest pad 20 formed when the chest pad 20 is covered with the subject 3 such as the chest.

Further, slide mechanisms 24 and 25 are provided inside the chest pad 20 at positions facing each other, and the optical fibers 2 are provided to the slide mechanisms 24 and 25, respectively.
6, 27 are provided at positions facing each other. The slide mechanisms 24 and 25 are adapted to slide the optical fibers 26 and 27 in the vertical direction under the control of the slide controller 28.

An optical lens 29 is arranged at the entrance of the optical fiber 26, and the laser light output from the laser oscillator 1 is condensed by the optical lens 29 and introduced into the optical fiber 26. A spherical lens 31 is arranged at the exit of the optical fiber 26. The optical lens is not limited to the spherical lens 31 and may be any optical lens that converts light into a parallel beam. An optical lens 30 is arranged at the exit of the optical fiber 27 so that the measurement laser light propagated through the optical fiber 27 is shaped and guided to the beam splitter 4. Next, the operation of the device configured as described above will be described.

First, the chest pad 20 covers the subject 3 as shown in FIG. At this time, the atmospheric pressure inside the chest pad 20 formed by the chest pad 20 and the subject 3 is the same as the atmospheric pressure. As a result, the flexible subject 3
Is free to move and its shape is indeterminate.

The exhaust pump 23 exhausts the gas in the chest pad 20 through the exhaust pipe 22, and the air pressure in the chest pad 20 is lowered below the atmospheric pressure by this exhaust. Then, when the atmospheric pressure inside the chest pad 20 drops to a predetermined atmospheric pressure, the exhaust by the exhaust pump 23 is stopped, and the atmospheric pressure inside the chest pad 20 is maintained at the predetermined atmospheric pressure. Due to this decrease in atmospheric pressure, the subject 3
Are raised and retain their shape, as shown in FIG.

In this state, the laser oscillator 1 outputs monochromatic laser light. This laser light is split into two directions by the beam splitter 2, and one of the laser lights is condensed by the optical lens 29 and is incident on the optical fiber 26. This laser light propagates in the optical fiber 26, is output from the exit port thereof, and is converted into a parallel beam by the spherical lens 31, and is irradiated onto the subject 3. Then, the laser light passes through the subject 3, enters the other optical fiber 27 as measurement laser light, propagates in the fiber 27,
It is shaped by the optical lens 30 and reaches the beam splitter 4.

At the same time, the other laser beam split by the beam splitter 2 is reflected by the mirror 6 and is incident on the acousto-optical element 7, which is frequency-modulated by the acousto-optical element 7 to become a reference laser beam. This reference laser light is reflected by the mirror 8 and reaches the beam splitter 4.

The beam splitter 4 superimposes the measurement laser beam and the reference laser beam and sends them to the photodetector 9.
The photodetector 9 outputs an electric signal corresponding to the intensity of the received laser light, and the electric signal is sent to the optical CT image processing apparatus 10.

Next, the chest pad 20 is replaced by a ball bearing 21.
It is rotated upward by a predetermined angle in the direction of arrow (a). Each optical fiber 26 is integrated with the rotation of the chest pad 20.
27 rotates about the subject 3 as a center, whereby the transmission angle of the laser beam to the subject 3 can be changed. After the rotation, the measurement laser beam and the reference laser beam transmitted through the subject 3 are superposed by the beam splitter 4, and the superposed laser beam is sent to the photodetector 9. Then, the photodetector 9 outputs an electric signal according to the intensity of the received laser beam, and the electric signal is sent to the optical CT image processing apparatus 10.

Thereafter, the chest pad 20 is rotated by a predetermined angle, and an electric signal for each rotation angle is sent to the optical CT image processing apparatus 10. However, the optical CT image processing apparatus 10
Is an electric signal for each rotation angle output from the photodetector 9 and performs image processing to obtain optical CT image data at a desired slice position in the subject 3.

The slide control device 28 also sends a slide control signal to each of the slide mechanisms 24 and 25. Receiving this slide control signal, each slide mechanism 24, 25
Slides the optical fibers 26 and 27 in the vertical direction in synchronization with each other. As a result, the transmission position of the laser beam with respect to the subject 16 moves vertically with respect to the subject 3. This vertical movement changes the transmission position of the laser light with respect to the subject 3. In this state, the measurement laser beam and the reference laser beam transmitted through the subject 3 are superposed by the beam splitter 4, the superposed laser beam is sent to the optical detector 9, and the electrical signal output from the optical detector 9 is transmitted as an optical signal. It is sent to the CT image processing apparatus 10.

Next, the chest pad 20 is rotated by a predetermined angle at the height position of each of the optical fibers 26, 27 that have slid in the same manner as described above. Then, the optical CT image processing apparatus 10 inputs the electrical signals for each rotation angle output from the photodetector 9, performs image processing with these electrical signals, and performs optical CT at the slice position where the height of the subject 3 is changed. Get image data.

As described above, in the above embodiment, the gas in the chest pad 20 when the subject 3 is covered with the chest pad 20 is exhausted by the exhaust pump 23 to reduce the atmospheric pressure in the chest pad 20. In this state, the subject 3 is irradiated with monochromatic laser light to integrally rotate the chest pad 20 around the subject, and the measurement laser light and the reference laser light transmitted through the subject 3 are rotated at each rotation angle. Since the optical CT image data of the subject 3 is obtained from the laser light on which
Optical CT image data of the subject 3 can be obtained without rotating the subject 3, and the entire apparatus can be miniaturized.
Further, it is possible to obtain optical CT image data at a desired slice position in the subject 3. And the optical fiber 26,
Since 27 is used, the influence of scattered light is reduced. further,
Optical CT image data at the best diagnostic position for the subject 3 can be easily obtained, and the same diagnostic position can be reproduced and diagnosed easily. For example, breast cancer can be accurately and easily diagnosed. become. Next, a modified example of the present invention will be described.

First, in the chest pad 20 shown in FIG. 6, the optical fibers 30a, 30b, ...
Is provided and these optical fibers 30a, 3
0d, ..., 30d, and optical fibers 31a, 31b ,. The laser light is incident on each of the optical fibers 30a, 30b, ... 30d by scanning the laser light from the laser oscillator 1 or branching by an optical branching device. Further, each measurement laser beam propagated through each optical fiber 31a, 31b, ... 31d is scanned and sent to the beam splitter 4.

In this way, a plurality of pairs of optical fibers 30a,
30b, ... 30d and optical fibers 31a, 31b, ... 3
By providing 1d, the amount of rotation of the chest pad 20 can be reduced when obtaining optical CT image data.

Next, in the chest pad 20 shown in FIG. 7, an optical fiber unit 32 on the laser light emitting side in which a plurality of optical fibers are arranged in an array and an optical fiber unit 33 on the laser light incident side which is paired with this optical fiber unit 32 are provided. It is provided. With this configuration, when the optical CT image data is obtained as in the above modification, the chest pad 20 is used.
The amount of rotation of can be reduced.

Next, FIG. 8 shows a technique for setting the rotation angle of the chest pad 20. A plurality of reflectors 34 are provided at predetermined intervals on the edge of the chest pad 20, and a photodetector 35 is placed at a predetermined position. It is arranged.

With this structure, if the photodetector 35 outputs a rotation setting signal each time the reflector 34 is detected, the breast pad 20 is rotated by a predetermined angle, and the subject 3 is rotated.
On the other hand, the subject 3 can be irradiated with laser light at each rotation angle.

Further, instead of providing an optical fiber on the chest pad 20, an optical lens or an optical window is provided, laser light is irradiated to the subject 3 through the optical lens or optical window, and the measurement laser light from the subject 3 is irradiated. The configuration may be such that the beam is guided to the beam splitter 4 through an optical lens or an optical window. Further, the object 3 can be measured as long as it can transmit the laser light.

[0028]

As described in detail above, according to the present invention, it is possible to provide an optical CT apparatus capable of obtaining optical CT image data without rotating the subject.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a chest pad in the same device.

FIG. 3 is a configuration diagram of a ball bearing in the chest pad.

FIG. 4 is a view showing a state of the same chest pad before exhaust.

FIG. 5 is a view showing a state after exhaustion of the chest pad.

FIG. 6 is a configuration diagram showing a modified example of the chest pad.

FIG. 7 is a configuration diagram showing a modified example of the chest pad.

FIG. 8 is a configuration diagram showing a mechanism for setting a rotation angle of the chest pad.

FIG. 9 is a block diagram of a conventional device.

[Explanation of symbols]

1 ... Laser oscillator, 2, 4 ... Beam splitter, 3 ... Subject, 6, 8 ... Mirror, 7 ... Acousto-optic element, 9 ... Photodetector, 10 ... Optical CT image processor, 20 ... Breast pad,
21 ... Ball bearing, 22 ... Exhaust pipe, 23 ... Exhaust pump, 24, 25 ... Slide mechanism, 26, 27 ... Optical fiber, 28 ... Slide control device, 29, 30 ... Optical lens, 31 ... Ball lens.

Claims (1)

[Claims] 1. A subject is irradiated with monochromatic laser light, the measurement laser light transmitted through the subject and a reference laser light obtained by frequency-modulating the laser light are superposed, and the superposed laser light is used to Optical CT for obtaining optical CT image of subject
In the apparatus, a cover that covers the subject, an exhaust unit that discharges gas in the cover when the subject is covered by the cover, and a laser beam that is disposed inside the cover and transmits the laser light. At least one pair of light projecting / receiving means for irradiating the subject with the measurement laser beam transmitted through the subject, and a rotating mechanism for integrally rotating the light projecting / receiving means around the subject. An optical CT device characterized by being provided.