KR102015428B1 - Apparatus and method for detecting optical and gamma image - Google Patents

Abstract

Disclosed are an apparatus for detecting an optical image and a gamma image.
Optical and gamma image detection apparatus according to an embodiment of the present invention, the scintillator for measuring the gamma rays to generate a flash image signal; An imaging lens coupled to a rear end of the scintillator and generating an optical image signal; An optical fiber image guide coupled to a rear end of the imaging lens and configured to transmit the flash image signal and the optical image signal to a rear end; An optical fiber taper coupled to a rear end of the optical fiber image guide and configured to enlarge the flash image signal and the optical image signal; An image multiplier coupled to a rear end of the optical fiber taper and amplifying the enlarged flash image signal and the optical image signal; And a camera module coupled to a rear end of the image multiplier and measuring the amplified flash image signal and the optical image signal.

Description

Apparatus and method for detecting optical and gamma image

The present invention relates to an apparatus and method for detecting an optical image and a gamma image. More specifically, the present invention relates to an optical endoscope and a method for detecting an optical image and a gamma image using an optical fiber endoscope for obtaining an optical image and a gamma image in minimally invasive surgery.

Nuclear medicine is a field for diagnosing or treating a physiological and pathological state of a human body by using radiation emitted from radioisotopes. The field of nuclear medicine has developed remarkably since the invention of cyclotron, which can manufacture medical radioisotopes.

Today's nuclear medicine uses radio labeling techniques to transform radioisotopes into the form of radio pharmaceuticals, primarily for diagnostic nuclear medicine imaging, which visualizes metabolism in the body. It is used.

Nuclear medicine is also used primarily for radioimunoscintigraphy, which images tumors by labeling radioisotopes that emit radiation to antibodies that are selective for specific tumor cells. In addition, it is used in radioimmunotherapy, which treats tumors by labeling radioisotopes.

In order for radiopharmaceuticals to be used for diagnosis and treatment of diseases, development of nuclear medicine equipment capable of measuring distribution and metabolic changes in abnormal tissues in which radiopharmaceuticals administered in the body are accumulated is essential. In other words, the development of nuclear medical imaging equipment that can specify the location and size of the labeled tumor is required.

In nuclear medicine surgery using radiopharmaceuticals, tumors are removed after confirming the images using single photon emission computed tomography (SPECT) and positron emission tomography (PET). do.

However, residual tumors left after dissecting tumors from internal organs cannot be completely removed only by the images confirmed by the surgeons. That is, there is a limit to bulky imaging equipment such as single photon emission tomography and positron emission tomography.

In order to overcome this limitation, a small imaging device capable of freely moving in an operating room and evaluating the presence or size of residual lesions is required. For example, the development of small medical devices such as intraoperative gamma probes has emerged, and research is being actively conducted.

In particular, the minimally invasive approach has become an important area of radiation-induced surgery, and in this minimally invasive surgery, gamma probes offer the possibility of easily identifying lesions during surgery. Known as the necessary device.

However, the gamma probes currently used in hospitals have some disadvantages to be applied to minimally invasive radio-guided surgery (MIRS). First, since commercially available gamma probes generally have a diameter of 12 mm, there is a bulky difficulty in performing an effective minimally invasive radiation guided surgery.

In addition, the gamma probe currently used in the clinic has a disadvantage in that it is vulnerable to strong electromagnetic fields and high frequency generated in other large medical equipment in the operating room because it is directly connected to the scintillator and can detect only a single radiation.

In addition, imaging gamma probes have a disadvantage of low spatial resolution and long data acquisition time for image realization. In addition, the gamma probe for imaging has a disadvantage in that the volume of the entire detection system is large because of an additional need for electronic equipment including a position encoding circuit for implementing an image.

Therefore, it is necessary to develop an endoscope apparatus having a small volume while detecting both an optical image and a gamma image at the same time.

The present invention has been made in an effort to provide an apparatus for detecting an optical image and a gamma image, and an optical image and gamma image detection method using the apparatus.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

An optical image and a gamma image detection apparatus according to an embodiment of the present invention for solving the technical problem, the scintillator for generating a flash image signal by measuring the gamma ray; An imaging lens coupled to a rear end of the scintillator and generating an optical image signal; An optical fiber image guide coupled to a rear end of the imaging lens and configured to transmit the flash image signal and the optical image signal to a rear end; An optical fiber taper coupled to a rear end of the optical fiber image guide and configured to enlarge the flash image signal and the optical image signal; An image multiplier coupled to a rear end of the optical fiber taper and amplifying the enlarged flash image signal and the optical image signal; And a camera module coupled to a rear end of the image multiplier and measuring the amplified flash image signal and the optical image signal.

Preferably, it may further include a UV filter film coupled to the front end of the scintillator, the ultraviolet filter.

Preferably, the scintillator is a LYSO (Ce) crystal.

Preferably, the scintillator is in the form of a disc having a diameter of 2 mm and a height of 1 mm.

Preferably, the imaging lens has the same diameter as the scintillator and the optical fiber image guide.

Preferably, the imaging lens is in the form of a cylinder having a diameter of 2 mm and a height of 7 mm.

Preferably, the optical fiber image guide is a coherent fiber-optic bundle, wherein the coherent fiber bundle is composed of a plurality of glass optical fibers having a step index.

Preferably, the optical fiber image guide is a flexible fiber-optic image guide or a rigid fiber-optic conduit.

Preferably, the optical fiber taper has a larger diameter at the rear end coupled with the image multiplier than the diameter of the front end coupled with the optical fiber image guide.

Preferably, the image multiplier is to multiply the light intensity of the two-dimensional planar image.

Preferably, the camera module is a camera based on a complementary metal-oxide semiconductor (CMOS).

According to another aspect of the present invention, there is provided an optical image and a gamma image detection method, which generate an optical image signal through an imaging lens and convert the generated optical image signal into an optical fiber taper through an optical fiber image guide. Transmitting, expanding the transmitted optical image signal through an optical fiber taper, and imaging the enlarged optical image signal through a camera module; And generating a flash video signal by measuring a gamma ray through a scintillator, transmitting the generated flash video signal to an optical fiber taper through an optical fiber image guide, and expanding the transmitted flash video signal through an optical fiber taper. And amplifying the flash image signal through an image multiplier and imaging the amplified flash image signal through a camera module.

Effects according to the present invention are as follows.

Using the optical fiber gamma endoscope proposed in the present invention, an optical image and a gamma image can be obtained simultaneously by detecting the position and distribution of radioisotopes in a very simple method even in a very narrow space. That is, the optical fiber gamma endoscope proposed in the present invention can obtain an optical image of a gamma source by arranging a transparent disc-shaped scintillator and a small imaging lens side by side, and at the same time, add an image multiplier tube to obtain a gamma image generated from the scintillator.

This enables real-time acquisition of images with high spatial resolution and counting efficiency during minimally invasive radiation-guided surgery. In addition, there is an advantage that a separate position coding circuit is not required by using a sensing probe and an image multiplier composed of a combination of a scintillator, an optical fiber image guide, and an optical fiber taper. This makes it possible to miniaturize the detection system.

Effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view for explaining a photographing method using a conventional single photon emission computed tomography (SPECT).
2 is a view for explaining an optical and gamma image detection apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram for describing the sensing probe illustrated in FIG. 2 in more detail.
4 is a view for explaining an optical image and a gamma image detection method according to an embodiment of the present invention.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a photographing method using a conventional single photon emission computed tomography (SPECT).

Where isotopes are used for nuclear medical examination, gamma rays or X-rays are emitted in the 4π direction. Single-photon emission tomography (SPECT) images the distribution of two-dimensional or three-dimensional isotopes by acquiring projection images using detectors at various angles.

When a projection image is obtained at a given angle, it is necessary to detect how much energy is emitted in one direction for one gamma ray or one X-ray. The most common way is to use physically aimed sights to determine which direction the location information, gamma or x-rays are emitted from.

Scintillators are usually used to convert gamma rays or X-rays into detectable signals. The most widely used scintillator for single photon emission computed tomography (SPECT) is NaI (Tl), which generates visible light when interacted with gamma or X-rays.

Photomultiplier tubes (PMTs) convert these visible light into electrical signals, optoelectronics, and multiply them to the magnitude of the detectable signal. Using the magnitudes of these signals, the position and energy information of gamma rays or X-rays are found and signal processed and displayed on a computer monitor.

Referring to FIG. 1, a single photon emission tomography apparatus includes a bed and a pedestal. When the testee P lies on the bed, the bed moves up and down and left and right, thereby placing the testee P between the rotary rings in which a gamma camera for detecting gamma rays is disposed.

As can be seen in Figure 1, the conventional single photon emission tomography (SPECT) has contributed to improving the quality of clinical diagnosis and early detection of disease, while requiring a large number of professionals in the scale and operation of the scale Has its drawbacks. In particular, it is difficult to easily detect tumors, lesions, or residual tumor tissue after surgery due to the small size of such equipment.

Therefore, it is necessary to develop a small gamma probe that can directly identify residual tumors or lesions during or immediately after surgery in a narrow environment such as an operating room. Accordingly, the present invention proposes an optical and gamma image detection apparatus as shown in FIG.

2 is a view for explaining an optical and gamma image detection apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the optical and gamma image detection apparatus 100 proposed in the present invention includes both a configuration for detecting an optical image and a configuration for detecting gamma spirituality. Each of them is explained as follows.

First, a configuration for detecting an optical image will be described first. Light emitted from the light source 110 passes through a UV filter film 130, which is converted into an optical image through an imaging lens 150 serving as an objective lens. The optical image thus obtained is transmitted to a fiber-optic taper 170 and a CMOS camera module 190 through a coherent image guide 160 connected to the imaging lens 150.

On the other hand, a configuration for detecting a gamma image will be described. By measuring the gamma ray 121 radiated from the disk-type radioisotope 120, a gamma image may be obtained through a transparent and thin disk-shaped scintillator 140 (LYSO: Ce disk). The gamma image thus obtained is transferred to a fiber-optic taper 170 through a fiber optic image guide 160 connected to the imaging lens 150, and an image multiplier 180 through the fiber taper 170. And amplified and then amplified and then transmitted to a CMOS camera module 190.

As described above, the optical and gamma image detecting apparatus 100 proposed in the present invention may obtain an optical image through the imaging lens 150 serving as an objective lens and simultaneously obtain a gamma image through the transparent and thin disk-shaped scintillator 140. have. This has the advantage that the shape and size of the radioisotope as well as the gamma ray distribution can be measured simultaneously.

That is, the optical and gamma image detection apparatus 100 proposed in the present invention includes a UV filter film 130, a disk scintillator 140, a small imaging lens 150, an optical fiber image guide 160, an optical fiber taper 170, It may include an image multiplier 180 and a silicon-metal semiconductor (CMOS) camera module.

Here, the disk-shaped radioisotope 120 is a device or material capable of emitting or artificially emitting radiation. Gamma sources that can be used as radioisotopes (120, Radioisotope) include Cs-137 and Co-60.

The sensing probe optically enlarges the scintillation image signal generated by the scintillator 140 by interaction with the gamma ray 121 emitted from the radioactive isotope 120, which is a radiation source, and enters the incident window of the image multiplier 180. do. The image multiplier 180 then multiplies the weak scintillation image signal generated by the sensing probe and incident.

In other words, light incident on the incident window generates photoelectrons through a photoelectric effect at a cathode of the image multiplier 180. Thereafter, the generated photoelectrons are accelerated by a microchannel plate (MCP) using a high voltage and then projected onto a phosphor screen to generate an optical signal in the visible light region where the light intensity is finally increased.

The image multiplier 180 multiplies the light intensity of the two-dimensional planar image signal, not the zero-dimensional optical signal. Therefore, no circuit for adjusting the offset voltage is required, and no Anger camera logic circuit for converting the position and the image signal is also required.

In particular, Gd 2 O 2 S: Tb may be used as the fluorescent material of the image multiplier 180, and a maximum wavelength is generated at 545 nm. In addition, the material of the incident window and the output window (that is, the opposite side of the incident window) of the image multiplier 180 is 40% higher light guiding efficiency than the glass using the optical fiber bundles, not the ordinary glass It has an image resolution of 28 lp / mm. In addition, the image multiplier 180 has a spectral gain of up to 3.3 x 106 W / W.

The camera module 190 generates a flash image by acquiring the final flash image signal generated through the focus lens. A camera based on a complementary metal-oxide semiconductor (CMOS) is used as the camera module 190. Therefore, the video can be measured at a frame rate of about 25 Hz per second, and the shutter speed and sensitivity settings can be changed using a dedicated program.

By using the image multiplier 180 and the camera module 190, the position detection circuit used in general nuclear medicine can be omitted. In addition, it is possible to obtain an image signal with a low driving voltage. In particular, the multiplication flash image signal may be acquired as a video file composed of 60 frames per second using the camera module 190.

The obtained video file is separated into individual frames using a MATLAB (MAtrix LABoratory) program, and the RGB scale is converted to gray scale (0 to 255). This is because the individual pixels that make up a frame are stored on an RGB scale.

Thereafter, the average of pixel values converted to gray scale is derived to obtain a final flash image. The region of interest (ROI) is designated as a circle around the site where the radiation is measured in the finally obtained final scintillation image. That is, the designation of the region of interest considers only the value of the gray scale of the pixel located in the region of interest. Finally, the gray scale value of the pixel corresponding to the ROI is summed to derive the light intensity change trend of the flash image signal according to the radiation change.

FIG. 3 is a diagram for describing the sensing probe illustrated in FIG. 2 in more detail.

Referring to FIG. 3, the sensing probe may include a UV filter film 130 for filtering ultraviolet (UV) light from the light source 110 at the front end. In addition, the sensing probe may include an imaging lens 150 that serves as an objective lens. In this case, the imaging lens 150 may have a cylindrical shape having a diameter of 2 mm and a thickness of 7 mm.

The rear end of the imaging lens 150 is coupled to the optical fiber image guide 160 having the same diameter as the imaging lens 150 to transfer the optical image obtained from the imaging lens 150 to the optical fiber taper 170. The optical fiber taper 170 transfers the optical image back to the CMOS camera module 190.

In this case, the transparent disk-shaped scintillator 140 may be coupled between the UV filter film 130 and the imaging lens 150. The scintillator 140 is used to detect gamma rays, and generally includes thallium-doped sodium iodide (NaI (TI)) and bismuth germinate (BGO). It is effective for splicing and has 4 times higher flash efficiency than BGO. And because of its transparent nature, it is easy to transmit optical images and generate flash images. The scintillator 140 may have the same diameter as the imaging lens 150 or the optical fiber image guide 160, and may have a disk thickness of 1 mm.

Referring to FIG. 3, the disk-shaped scintillator 140 generates a scintillation image by measuring gamma rays and transmits the scintillation image signal to the optical fiber image guide 160 connected to the imaging lens 150. The optical fiber image guide 160 transmits the flash image signal to the optical fiber taper 170, and the optical fiber taper 170 enlarges the flash image signal to generate an enlarged flash image signal.

At this time, the disk-shaped scintillator 140 can be attached or detached as necessary. That is, since the flashing efficiency varies depending on the energy and / or radioactivity of the radiation to be measured, the scintillator 140 having a different thickness can be removed and used according to the type of radiation source that emits gamma rays.

The optical fiber image guide 160 transmits the flash image signal generated by the scintillator 140 to the optical fiber taper 170. To this end, the fiber optic image guide 160 is comprised of coherent fiber-optic bundles. In particular, the coherent fiber bundle may consist of a plurality of glass optical fibers having a stepped index of refraction. For example, it is produced from about 3,000 or more glass fiber bundles having a diameter of about 100 μm.

The optical fiber image guide 160 may also be a flexible fiber-optic image guide or a rigid fiber-optic conduit. In addition, the optical fiber image guide 160 is an image guide (image guide) used in the medical endoscope delivers the image inside the body captured by the light to the outside, which combines the detection of the scintillation image.

For example, the individual optical fibers used in optical fiber imaging conduits have stepped indexes of refraction, and the refractive indexes of the core and cladding are about 1.58 and about 1.49, respectively, and the numerical aperture (numerical aperture, NA) is about 0.53. In addition, the packing fraction (PF) of each optical fiber constituting the optical fiber image conduit is 100% and has a light collection efficiency, and an image resolution of about 5 lp / mm.

Thus, a flash image generated by the scintillator 140 is formed inside one end of the optical fiber image guide 160, and the transmitted flash image having the same size and properties as the generated flash image is the other end of the optical taper 170. It is formed inside. The transmitted flash image is transmitted to the optical fiber taper 170 side.

In general, the optical fiber serves to transmit the flash image signal generated from the scintillator 140 to the optical measuring device, and has an advantage of transmitting the optical signal at a long distance without being affected by temperature, pressure, high frequency, and electromagnetic waves.

The optical fiber taper 170 enlarges or reduces the transmitted flash image incident on the incident surface and transmits the image. In particular, the area of the incident surface and the output surface is composed of different optical fiber bundles. In addition, the diameter of the incident surface coupled to the front end of the optical fiber image guide 160 may be increased toward the output surface side to be smaller than the area of the output surface.

In addition, an area ratio between the incident surface and the output surface of the optical fiber taper 170 is about 1: 2.27, and the glare image is transmitted at the same magnification. Since the distal end of the optical fiber taper 170 bonded to the optical fiber image conduit is a small surface, the flash image signal transmitted to the proximal end, which is a large surface area, is generated by the scintillator 140. The image is 2.27 times larger than the image. In addition, the numerical aperture of the optical fiber taper 170 is 1, and may have an image resolution of about 102 lp / mm.

4 is a view for explaining an optical image and a gamma image detection method according to an embodiment of the present invention.

Referring to FIG. 4, an enlarged scintillation image signal is generated by measuring gamma rays emitted from the radioisotope 110 (S1100, S1210, and S1310). In this case, an optical image is obtained through the imaging lens 150 (S1210). The optical image thus obtained is transmitted to the fiber-optic taper 170 and the CMOS camera module 190 through the optical fiber image guide 160 connected to the imaging lens 150 (S1230). , S1250, S1400).

In addition, the gamma ray emitted from the radioisotope 110 may be measured through a transparent and thin disk-shaped scintillator 140 (LYSO: Ce disk) to obtain a gamma image (S1310). The gamma image thus obtained is transferred to a fiber-optic taper 170 through a fiber optic image guide 160 connected to the imaging lens 150, and an image multiplier 180 through the fiber taper 170. And amplified and then amplified and then transmitted to a CMOS camera module 190 (S1330, S1350, S1370, and S1400).

When the optical image and the gamma image are generated, the separate image signal processing unit designates a region of interest in the flash image, and calculates a distribution of gamma rays by using the light intensity in the region of interest. The camera module 190 is used to acquire a multiplication flash video signal as a video file composed of 60 frames per second. The obtained video file is separated into individual frames using a MATLAB (MAtrix LABoratory) program, and the RGB scale is converted to gray scale (0 to 255).

Thereafter, the average of pixel values converted to gray scale is derived to obtain a final flash image. A region of interest (ROI) is designated as a circle around the site where the radiation is measured in the finally obtained final scintillation image. That is, the designation of the region of interest considers only the value of the gray scale of the pixel located in the region of interest. Finally, the gray scale value of the pixel corresponding to the ROI is summed to derive the light intensity change trend of the flash image signal according to the radiation change.

On the other hand, the image signal processing unit may be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment such that instructions executed through the processor of the computer or other programmable data processing equipment may not be included in each block or flowchart of the block diagram. It will create means for performing the functions described in each step.

Through this process, not only the shape and size of the radioisotope but also the gamma ray distribution can be measured simultaneously. When the minimally invasive radiation-guided surgery is performed using the optical image and gamma image detection apparatus, the lesion can be easily identified during the operation, and the residual tumor can be easily detected.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

100: optical and gamma image detection device
130: UV filter film
140: scintillation body
150: imaging lens
160: optical fiber image guide
170: fiber optic taper
180: video multiplier
190: CMOS camera module

Claims (10)

A detachable scintillator which measures a gamma ray to generate a scintillation video signal;
An imaging lens coupled to a rear end of the scintillator and generating an optical image signal;
An optical fiber image guide coupled to a rear end of the imaging lens and configured to transmit the flash image signal and the optical image signal to a rear end;
An optical fiber taper coupled to a rear end of the optical fiber image guide and configured to enlarge the flash image signal and the optical image signal;
An image multiplier tube formed of a bundle of optical fibers and coupled to a rear end of the optical taper and amplifying an enlarged flash image signal and an optical image signal; And
A camera module coupled to the rear end of the image multiplier and measuring the amplified flash image signal and the optical image signal,
The scintillator,
LYSO (Ce) crystals, 2mm in diameter, 1mm in height, disc shaped,
The imaging lens,
Having the same diameter as the scintillator and the optical fiber image guide, and having a cylindrical shape with a diameter of 2 mm and a height of 7 mm,
Optical image and gamma image detection device. delete delete delete delete The method of claim 1,
The optical fiber image guide,
Coherent fiber-optic bundles,
The coherence fiber bundle,
It consists of a plurality of glass optical fibers having a step index of refraction,
Optical image and gamma image detection device. The method of claim 6,
The optical fiber image guide,
Flexible fiber-optic image guide or rigid fiber-optic conduit,
Optical image and gamma image detection device. The method of claim 1,
The optical fiber taper,
The diameter of the rear end coupled to the image multiplier is larger than the diameter of the front end coupled to the optical fiber image guide,
Optical image and gamma image detection device. The method of claim 1,
The image multiplier,
To multiply the light intensity of a two-dimensional plane image,
Optical image and gamma image detection device. An optical lens generates an optical image signal, transmits the generated optical image signal to an optical fiber taper through an optical fiber image guide, enlarges the transmitted optical image signal through an optical fiber taper, and expands the enlarged optical image signal. Imaging through a camera module; And
Measuring a gamma ray through a scintillator to generate a scintillation video signal, transmitting the generated scintillation video signal to an optical fiber taper through an optical fiber image guide, enlarging the transmitted scintillation video signal through an optical fiber taper, and expanding the flash Amplifying an image signal through an image multiplier and imaging the amplified flash image signal through a camera module;
The flashing body which can be attached and detached,
LYSO (Ce) crystals, 2mm in diameter, 1mm in height, disc shaped,
The imaging lens,
It has the same diameter as the scintillator and the optical fiber image guide, and has a cylindrical shape with a diameter of 2 mm and a height of 7 mm,
Optical and gamma image detection method characterized in that the material of the incident window and the output window of the image multiplier made of a bundle of optical fibers.

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