JPH0678905A - Layered product used in energy subtraction process for x-ray image - Google Patents

Abstract

PURPOSE:To obtain a subtraction image with high space resolution by interposing a filter made of an X-ray low energy component absorbing material between two sheets of phosphor intensifying screen disposed between two sheets of X-ray photographic films. CONSTITUTION:An X-ray 6 from an X-ray source 4 transmits an object 7 to reach an X-ray film A and a phosphor intensifying screen (a). At this time, an X-ray image of the object 7 is recorded on the film A. Subsequently, the X-ray which has transmitted the intensifying screen (a) transmits a filter 3 to reach intensifying screens (b), (c) and a film B, and an X-ray image of the object 7 is recorded on the film B. At this time, the filter 3 absorbs much more X-ray low energy components, so that the X-ray which has transmitted the filter 3 is decreased in its low energy components and intensified in its energy components. Accordingly, an X-ray image of the object 7 decreased in its image information related to X-ray low energy components is recorded on the film B. Thus, there is no time difference in formation of two X-ray images to be subjected to subtraction.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the energy of X-ray images.
A radiographic film-fluorescent intensifying screen-filter laminate used in the subtraction method.

More specifically, an X-ray film and an intensifying screen are used to record an X-ray image on the X-ray film, and then the X-ray film on which the X-ray image is recorded is optically processed. In an X-ray image recording / reproducing system for scanning an X-ray image photoelectrically by a photodetector in the form of transmitted light or reflected light, subjecting the obtained image signal to signal processing, and then reproducing it as a visible image. The present invention relates to an X-ray photographic film-fluorescent intensifying screen-filter laminate used in an energy subtraction method for X-ray images.

[0003]

2. Description of the Related Art Different energies for the same subject
By irradiating X-rays having a distribution, X-ray energy peculiar to a specific structure (eg, organ, bone, blood vessel) of the subject
Taking advantage of its absorption properties, two X-ray images were obtained in which a specific structure was extracted differently, and then these two X-ray images were obtained.
A so-called energy subtraction method, in which a line image is appropriately weighted and then an image of a specific structure is extracted by performing subtraction (subtraction) between the two images, is also called a digital subtraction method (also referred to as digital radiography). (Abbreviated as DR). Here, as DR, the existing I.I.
Digital fluoroscopy (Digital) that digitally processes the output of an X-ray fluoroscopic camera consisting of a camera and a TV camera.
Fluoroscopy) and Xe-X used for CT such as detector
Scanned projection radiography that uses line detection system
graphy) is known.

More specifically, the following various methods are known as conventional energy subtraction methods.

(I) X having different energy distributions
The subject is irradiated with a line intermittently at short time intervals, and X-rays transmitted through the subject are synchronized with the I-I tube and TV.
A method of obtaining a subtraction image from two or more X-ray images obtained by detecting with an X-ray fluoroscopic camera including a camera or an X-ray detector such as an Xe-detector. Here, as a method of irradiating X-rays having different energy distributions, i) an X-ray source having such different energy
Remodeling so as to radiate X-rays having a distribution, ii) Proximity of two or more X-ray sources emitting X-rays having different energy distributions so that X-rays emitted from them do not interfere with each other. Iii) There is a method of inserting and removing a filter that changes the energy distribution of X-rays between the X-ray source and the subject.

(II) X having different energy distributions
Two X-ray sources capable of simultaneously radiating rays are arranged close to each other, and a large number of fine slits or fine holes (for example, circles or square holes arranged in a checkered pattern) are arranged. A filter made of an X-ray shielding material such as lead having a structure in which the area ratio between the X-ray shielding portion and the void portion is 1: 1 is provided on one side of the light receiving surface of the X-ray detector. From the X-ray from the other X-ray source
The X-ray sources are inserted between the X-ray source and the subject so that the X-rays do not interfere with each other, and the X-rays are simultaneously radiated to the subject from the two X-ray sources in such a state. Forming an X-ray image on the light receiving surface of the X-ray detector and detecting the X-ray image by the X-ray detector, and separating the detected X-ray image at the time of reading or after reading, A method of obtaining a subtraction image from separated images.

(III) While the subject is moved relative to the X-ray source and the X-ray detector, fan-shaped X-rays having different energy distributions are continuously generated from the X-ray source alternately for a certain period of time. , Fan-shaped X-rays transmitted through the subject are detected by an X-ray detector installed behind the subject, X-ray images corresponding to X-rays having different energy distributions are obtained from the obtained image signals, and then those X-rays are obtained. A method of obtaining a subtraction image from a line image. As a method of generating X-rays having different energy distributions, the same method as (I) can be considered.

(IV) A filter having the same shape as the filter used in the method (II) is made of a metal such as copper that absorbs low energy components of X-rays, and this filter is used as one X-ray source and an object. And X-rays having different energy distributions which do not interfere with each other on the light-receiving surface of the X-ray detector, are generated from the X-rays emitted from the X-ray source,
An X-ray image is formed on the light-receiving surface of the X-ray detector by the X-rays having different energy distributions, the X-ray image is detected by the X-ray detector, and the detected X-ray image is read out, or A method of separating after reading and obtaining a subtraction image from the separated images.

The energy subtraction method can separate and extract the images of the structures of the subject having different energy absorption characteristics, and can form the image of only the soft tissue excluding the bones. For example, it is possible to separate and extract an image of a structure such as a bronchus existing in the mediastinum, which has been difficult to be diagnosed by overlapping with a bone in the related art, from the image of the bone. In addition, when performing temporal subtraction in imaging such as abdominal angiography, the artifact due to the abdominal gas image becomes a problem, but the energy subtraction method can erase the information on the soft tissue, and the gas image can be erased. It is possible to form only bones and contrast-enhanced images. Therefore, the energy subtraction method can obtain diagnostic information that could not be obtained by the conventional method, and is a method that is attracting attention in the medical diagnostic field in principle as a very outstanding method.

[0010]

However, the above-mentioned conventional energy subtraction method has an essential drawback related to DR. That is, the spatial resolution of the subtraction image obtained by DR is generally I.S.
I. It is determined by the resolution of an X-ray fluoroscopy camera consisting of a tube and a TV camera or an X-ray detector such as an Xe-detector. The resolution is not very high and therefore the conventional energy
-The subtraction method has a problem that it is impossible to make a minute diagnosis for a specific structure. Furthermore, D
Since the imaging range in R is limited by the light receiving area of the X-ray detector, the conventional energy subtraction method has a problem that it is not possible to simultaneously obtain a subtraction image for a wide range of structures of an object.

Further, the conventional energy subtraction methods (I), (II), (III) and (IV) have the following drawbacks.

1. A special X-ray source is required [method (I) and method (II)].

2. Misalignment occurs between corresponding pixels of two X-ray images [method (I), method (II), method (III) and method (I when two X-ray sources are used)
V)].

3. Only half the resolution can be obtained as compared with the usual X-ray image forming method [method (II) and method (IV)].

4. Since each X-ray image by X-rays having different energy distributions is formed on the same plane, it is difficult to separate the X-ray images at the time of reading or after the reading [Method (II ) And method (IV)].

5. Since X-rays having different energy distributions are intermittently applied to the copy, a positional shift occurs between the images due to muscle movement, respiratory movement, peristalsis, etc. of the subject, resulting in good results. A subtraction image cannot be obtained [method (I)].

6. Since the subject is scanned by the fan-shaped X-rays, it takes time to form one image, and there is a time difference between the beginning and the end of the scanning, and each image is affected by the subject's muscular movement, respiratory movement, peristalsis, etc. As a result, a good subtraction image cannot be obtained, which is not suitable for extracting an angiographic image [Method (III)].

In view of the above circumstances, an object of the present invention is not to have the drawbacks of the above-mentioned conventional energy subtraction method, but to obtain an excellent subtraction image energy of an X-ray image. -To provide an X-ray film-fluorescent intensifying screen-filter laminate as an X-ray detector used in the subtraction method.

[0019]

In order to achieve the above object, the laminate used in the energy subtraction method for X-ray images according to the present invention is: a) Two X-ray photographs arranged in a laminated state. Film, b) two fluorescent intensifying screens arranged between these radiographic films and having a phosphor layer on the side of these radiographic films, c) with respect to one of said radiographic films, said fluorescent film A fluorescent intensifying screen disposed on the side opposite to the intensifying screen and having a phosphor layer on the side of the radiographic film, and d) two fluorescents disposed between the radiographic films. It is characterized by comprising a filter made of a substance absorbing a low energy component of X-rays interposed between intensifying screens.

An X-ray image is once recorded on the X-ray photographic film, and the X-ray photographic film on which the X-ray image is recorded is optically scanned to photoelectrically convert the X-ray image in the form of transmitted light or reflected light. Have been already proposed by the present applicant or an X-ray photographic recording / reproducing system for recording / reproducing an X-ray image by performing signal processing on the image signal obtained by this detection and reproducing it as a visible image. (Japanese Patent Laid-Open No. 54-121043).

Generally, an X-ray photographic film is required to have a high sensitivity suitable for X-ray photography and a wide exposure range, and to have high contrast, high sharpness and fine graininess suitable for observation and interpretation. However, these characteristics are often inconsistent with each other, and it is difficult to produce an X-ray photo film satisfying all the characteristics, and the film was designed at the sacrifice of photographing suitability and observation and interpretation suitability. However, the use of the above X-ray image recording / reproducing system can improve the contrast, sharpness, and graininess, and thereby improve the diagnostic performance of the X-ray image. Therefore, a lot of diagnostic information can be obtained, and at the same time, the X-ray photographic film can be provided with a better imaging suitability.

The X-ray image energy subtraction method using the laminate of the present invention utilizes the above X-ray image recording system. That is, the energy subtraction method for X-ray images using the laminated body of the present invention uses two X-ray detectors instead of the X-ray detector used in the conventional energy subtraction method described above. Using an X-ray photographic film-fluorescent intensifying screen-filter laminate as an X-ray detector, wherein the photographic film is arranged in a laminated state together with a fluorescent intensifying screen and a filter made of a low energy component absorbing material for X-rays, This laminated body is irradiated with X-rays transmitted through an object including a specific structure having a different X-ray energy-absorption characteristic, and the laminated body has different image information of a portion corresponding to the specific structure. Record two X-ray images,
After that, the subtraction image is obtained from two X-ray images read from the two films forming the laminated body, and the problem that the conventional energy subtraction method has is solved. It is a thing.

That is, the energy subtraction method for an X-ray image using the laminate of the present invention comprises: a) two X-ray photographic films arranged in a laminated state; and b) an arrangement between the X-ray photographic films. And two fluorescent intensifying screens having a phosphor layer on the side of the X-ray film, c) with respect to one of the X-ray film, disposed on the opposite side of the intensifying screen, And a fluorescent intensifying screen having a fluorescent layer on the side of the X-ray photographic film, and d) the X-rays interposed between the two intensifying screens arranged between the X-ray photographic films. An X-ray photo film-fluorescent intensifying screen-filter laminate consisting of a filter made of a low energy component absorbing material is irradiated with X-rays transmitted through an object from one end side of the laminate where the X-ray photo film is located. The two X-ray film films that make up this laminate are The low energy component of X-rays is absorbed and reduced in the portion corresponding to the above-mentioned specific structure in the X-ray film placed farther from the subject than in the X-ray film placed closer to the subject. An X-ray image is recorded on the two X-ray photographic films so that image information is recorded, and then the two X-ray photographic films are optically scanned to record the X-ray image on the film. Is photoelectrically read in the form of transmitted light or reflected light to be converted into a digital image signal, and the digital image signal is subtracted between the corresponding pixels of the two X-ray images converted into the digital image signal to determine the above-mentioned specification. The image of the structure is extracted.

In the energy subtraction method for an X-ray image using the laminate of the present invention, the subtraction of the digital image signal between the corresponding pixels of the X-ray image means that the corresponding pixel of the X-ray image is subtracted. This means obtaining a new image signal by multiplying the digital image signal by a weighting coefficient and performing subtraction. Further, the X-ray low energy component absorbing substance means a substance that absorbs the low energy component more than the high energy component of the X-ray.

The laminated body of the present invention has two layers arranged in a laminated state.
A filter made of a substance absorbing a low energy component of X-rays is interposed between two fluorescent intensifying screens arranged between two X-ray photo films, and the X-ray transmitted through a subject by this filter.
The filter that absorbs the low energy component of X-rays, and the filter made of the low energy component absorbing substance of X-ray may be made of only the low energy component absorbing substance of X-ray, or It may consist of a low energy component absorbing substance and another substance containing this substance in a dispersed state.

The X-ray low energy component absorbing substance means a substance which absorbs a low energy component more than a high energy component of X-ray, and a specific example thereof is a metal, and Cu is particularly preferable. , W, Mo, Ni, Pb, Au, Ag, Ba, T
a, Fe, Al, Zn, Cd, Ti, Zr, V, Nb, Cr, Co and S
It is preferably at least one of n.

In the energy subtraction method for an X-ray image using the laminate of the present invention, two Xs to be subtracted to obtain a subtraction image.
The subtraction is performed between the corresponding pixels of the line image, and this subtraction should be subtracted by 2 as described above.
This means to obtain a new image signal by multiplying the image signal of the corresponding pixel of one X-ray image by a weighting coefficient and performing subtraction. When this subtraction is expressed by an equation, L = m P−n Q (where P and Q are digital image signals of two X-ray images to be subtracted, m and n are weighting factors, and L is a new image signal) Become. In order to erase the image information other than the image information regarding the specific structure to be extracted in obtaining the subtraction image, it is preferable to match the intensity distributions of the image signals of the portions to be deleted between the two images to be subtracted. For this purpose, it is convenient to match the gradation of the part to be erased. In order to realize this, it is preferable to perform the subtraction by selecting the weighting factors m and n so that the gradations of the portions to be erased of both images match. Depending on the shooting conditions, m = n, and further m = n = 1. In addition, in the two images to be subtracted, various structures are complicatedly overlapped and recorded as an integral image, so the above weighting coefficient is not necessarily a constant, and in some cases becomes a function of the thickness of the structure, It may have linearity.

As a specific method of the above subtraction, a weighting factor is selected so that the intensity distributions of the regions of the structure to be erased (for example, soft tissue such as lungs in a chest image) are matched, and all of the two images to be subtracted. There is a method of multiplying the image signal of the pixel by the weighting coefficient. According to this method, the region of only the soft tissue in the two images to be subtracted has a constant intensity, and when subtraction is performed between the two images to be subtracted, the image information regarding the soft tissue is lost and only the bones are lost. Image information is extracted as a difference. Therefore, it is preferable to practice such a simple method.

In the energy subtraction method for an X-ray image using the laminated body of the present invention, an X-ray for irradiating a subject with X-rays separated into a high energy band and a low energy band by a specific filter in advance. When used as X-rays, the separation of the high-energy component and the low-energy component of X-rays in the X-ray film-fluorescent intensifying screen-filter laminate is further facilitated, which is preferable.

Further, in the laminate of the present invention, making the thickness of the fluorescent intensifying screen placed closer to the subject smaller means reaching the fluorescent intensifying screen placed farther from the subject. It is effective in preventing dose reduction.

In the X-ray image ergi subtraction method using the laminate of the present invention, as means for optically scanning the X-ray film for reading the X-ray image from the X-ray film, a light is used. A method of scanning a beam two-dimensionally on an X-ray photographic film, a method of fixing an optical beam and mounting the X-ray photographic film on a rotating drum, and moving the beam in a direction parallel to the rotation axis, or Various means such as electronic scanning such as a flying spot scanner can be used. As the light beam, various ones such as a laser beam obtained by condensing light emitted from a point light source with a condenser lens can be used. Reading can be performed by detecting reflected light or transmitted light (when the X-ray film is transparent) from the X-ray image when the X-ray photographic film is optically scanned by the light detecting means.

In the energy subtraction method for an X-ray image using the laminate of the present invention, various signal processing can be performed on the X-ray image before or after the subtraction. The signal processing used is as follows. JPA
56-11035, 56-75136, 56-75138, 56-75140
No. 56-91735 and the like, and the gradation processing disclosed in JP-A-55-116338 and JP-A-55-88741.

[0033]

When the energy subtraction of the X-ray image is performed using the laminate of the present invention, the absorption of the low energy component of the X-ray transmitted through the subject is different from that of the fluorescent intensifying screen. Since it is carried out by a filter provided as a body, it is possible to efficiently absorb the low energy component of X-rays, and the fluorescent intensifying screen can also be diverted as it is for the simple photographing. This is very convenient because it can be done.

If energy subtraction of an X-ray image is carried out using the laminate of the present invention, X-ray image can be read out.
It is possible to reduce the spot diameter of the light beam scanning on the line-photographic film to increase the number of pixels per unit area, and to reduce the image data after the subtraction process and various signal processes. Since the final output can be directly recorded on a light-sensitive material such as silver salt, a subtraction image with a significantly higher spatial resolution than that of the conventional DR can be obtained. A clear subtraction image having spatial resolution can be obtained. At the same time, there is no technical problem in enlarging the area of the X-ray film or the fluorescent intensifying screen, so that a subtraction image can be obtained at a time for a large area covering a wide range of structures of the human body. it can.
When the energy subtraction of the X-ray image is performed by using the laminated body of the present invention as described above, the essential problem due to the X-ray detector in the DR is solved.

When energy subtraction of an X-ray image is performed using the laminate of the present invention, X-rays emitted from an X-ray source and transmitted through an object are X-ray photographic film-fluorescent intensifying screen-filter. Since each X-ray film forming the laminate is irradiated at the same time, it should be subtracted.
There is no time difference between the formation of the two X-ray images, and therefore, the subtraction image of the specific structure of the human body, which changes moment by moment, can also be obtained as a good image.

Further, if the energy subtraction of the X-ray image is carried out by using the laminate of the present invention, a single X-ray source can be used, so that a positional deviation occurs between the corresponding pixels of the two X-ray images. Never.

Furthermore, if energy subtraction of an X-ray image is carried out using the laminate of the present invention, the conventional general-purpose X-ray generator and imaging device can be used as they are.

Further, when the energy subtraction of the X-ray image is carried out by using the laminate of the present invention, the X-ray images for the X-rays having different energy distributions are recorded in separate X-ray photographic films. Also, there is no problem that the images must be separated at the time of reading or after the reading, and the resolution is not halved by obtaining the subtraction image.

As described above, when the energy subtraction of the X-ray image is performed using the laminate of the present invention, the problems of the conventional energy subtraction method can be solved at once.

[0040]

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of an X-ray film-fluorescent intensifying screen-filter laminate used in the X-ray image energy subtraction method of the present invention. The X-ray photo film-fluorescent intensifying screen-filter laminate (hereinafter simply referred to as a laminate) shown in FIG. 1 is composed of two X-ray photo films A and B arranged in a laminated state, and these two X films. Two fluorescent intensifying screens a and b disposed between the radiographic films A and B and having a phosphor layer on the side of the radiographic films A and B, one of the radiographic films B, Fluorescent intensifying screen c, which is arranged on the side opposite to the fluorescent intensifying screens a and b, and has a phosphor layer on the side of the X-ray photographic film B, and the X-ray photographic films A and B.
It comprises a filter 3 made of a low energy component absorbing material for X-rays, which is interposed between two fluorescent intensifying screens a and b disposed therebetween.

Fluorescent intensifying screens a, b and c are X-rays such as polyethylene terephthalate or cellulose acetate.
Provided on supports 2a, 2b and 2c formed of a radiation-transmissive material, and phosphor layers 1a, 1b and 1c, which are prepared by dispersing X-ray phosphors in an appropriate binder. Is. The surface of the phosphor layers 1a, 1b and 1c of the fluorescent intensifying screens a, b and c (the surface on the side opposite to the support 2a, 2b and 2c side) is physically covered with the phosphor layers. Alternatively, a protective film such as a polyethylene terephthalate film for chemical protection may be provided.

In the laminate shown in FIG. 1, the fluorescent intensifying screens a, b and c may be so-called self-supporting fluorescent intensifying screens having no support. The filter 3 may be composed of an X-ray low energy component absorbing substance and another substance containing this substance in a dispersed state,
Alternatively, the filter 3 may be composed only of a low-energy component absorbing X-ray, and the filter 3 absorbs the low-energy component of X-ray transmitted through the subject.

FIG. 2 shows an X-ray image for energy subtraction using the stack shown in FIG.
It is a schematic diagram explaining a mode that an X-ray image is recorded on a radiographic film. A single X-ray source 4 that emits X-rays 6 is arranged in the upper part of the figure, and the laminated body shown in FIG. 1 is arranged in a cassette 5 behind the subject 7.

When X-rays 6 are emitted from the X-ray source 4, the X-rays 6 pass through an object 7 including a specific structure having a different X-ray energy-absorption characteristic and pass through an X-ray photographic film A. And reach the fluorescent intensifying screen a. Here, the X-ray image of the subject 7 is recorded on the X-ray photographic film A. Next, the X-rays that have passed through the X-ray photographic film A and the fluorescent intensifying screen a pass through the filter 3 to reach the fluorescent intensifying screens b and c and the X-ray photographic film B, and the X-ray photographic film B. An X-ray image of the subject 7 is recorded at. Here, since the filter 3 absorbs more of the low energy component of X-ray, the X-ray transmitted through the filter 3 has a low energy component and a high energy component.
Therefore, the X-ray image of the subject 7 in which the image information related to the low energy component of X-ray is reduced is recorded on the X-ray photographic film B. In this way, two X-ray images having different image information in the portion corresponding to the specific structure of the subject 7 are simultaneously recorded on the two X-ray photographic films A and B.

An X-ray image is read from the thus obtained two X-ray photographic films A and B by a reading system as shown in FIG. 3 to obtain a digital image signal representing the image. First, while moving the X-ray photographic film A in the direction of arrow Y for sub-scanning, the laser light 11 from the laser light source 10 is main-scanned in the X-direction by the scanning mirror 12, The X-ray image recorded on the film X is read from the X-ray film A as reflected light 13. The reflected light 13 is incident on the inside of the light collecting plate 14 from one end surface of the light collecting plate 14 formed by molding a transparent acrylic plate and reaches the photo-mal 15 while repeating total reflection inside, and the amount of light is the image signal S.
Is output as. The output image signal S is supplied to a logarithmic value (lo) by a logarithmic converter 16 including an amplifier and an A / D converter.
g S) is converted into a digital image signal log S _A. The digital image signal log S _A are input to the digital calculator 17 and stored therein. Next, in the same manner, the recorded image of the other one of X-ray photographic film B is read, the digital image signal log S _B are stored in the digital arithmetic unit 17. In the digital computing unit 17, the digital image signal log S _A is converted to the digital image signal log S _A between the corresponding pixels.
The image signal of the specific structure to be extracted is obtained by subtracting _B. At this time, the digital image signals log S _A and log
Each S _B is multiplied by an appropriate weighting factor, but the two weighting factors are preferably chosen so that the tones of the portions of both images to be erased match. The digital image signal is treated as a logarithmic value here because the band compression of the image data is performed and unnecessary image information can be completely removed. It is also possible to do the same with signals.

In this way, the signal obtained by performing the digital subtraction processing is subjected to image processing such as spatial frequency processing, gradation processing, and averaging processing, if necessary, and then displayed on a CRT or the like. It is reproduced directly on the apparatus or reproduced and recorded on a recording material such as a photosensitive film as described below.

FIG. 4 shows an example of image scanning recording for reproduction. The photosensitive film 20 is moved in the sub-scanning direction of the arrow Y, and the laser beam 21 is mainly scanned in the X direction on the photosensitive film 20 so that the laser beam 21 is an A / O modulator. A visible image is formed on the photosensitive film 20 by modulating with the image signal from the image signal supplier 23 by 22. If the output of the digital calculator 17 is used as this image signal, an image of a desired specific structure subjected to digital subtraction processing can be reproduced and recorded on the photosensitive film 20.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of an X-ray film-fluorescent intensifying screen-filter laminate used in the present invention.

FIG. 2 is a schematic diagram illustrating how an X-ray image of a subject is recorded on the stack shown in FIG.

FIG. 3 is a schematic diagram illustrating steps of photoelectrically converting an X-ray image recorded from an X-ray photographic film in the form of reflected light to obtain a digital signal and performing subtraction processing on the digital signal.

FIG. 4 is a schematic diagram illustrating steps for reproducing and recording an image subjected to subtraction processing on a photosensitive film by using a signal obtained by the subtraction processing.

[Explanation of symbols]

 A, B X-ray film a, b, c Fluorescent intensifying screen 1a, 1b, 1c Fluorescent material layer 2a, 2b, 2c Support 3 Filter 4 X-ray source 6 X-ray 7 Subject 10 Laser light source 11 Laser light 12 Scanning mirror 13 Reflected light 14 Condenser plate 15 Photomul 16 Logarithmic converter 17 Digital calculator 20 Photosensitive film 21 Laser light 22 A / O modulator 23 Image signal supplier

Claims (5)

[Claims] 1. A) two radiographic films arranged in a laminated state, b) two fluorophores arranged between these radiographic films and having a phosphor layer on the side of these radiographic films. Photosensitizing screen, c) a fluorescent intensifying screen which is disposed on the side opposite to the fluorescent intensifying screen with respect to one of the X-ray photographic films and which has a phosphor layer on the X-ray photographic film side. And d) an X-ray film-fluorescent film comprising a filter made of a low energy component absorbing substance of X-rays interposed between two fluorescent intensifying screens arranged between the above-mentioned X-ray film. Sensitive paper-filter laminate. 2. The low energy of the X-rays by the filter.
The X-ray film-fluorescent intensifying screen-filter laminate according to claim 1, which comprises a component-absorbing substance and another substance containing the substance in a dispersed state. 3. The low energy of the X-rays by the filter.
The X-ray film-fluorescent intensifying screen-filter laminate according to claim 1, wherein the laminate comprises only a component-absorbing substance. 4. The X-ray photographic film-fluorescent intensifying screen-filter laminate according to claim 1, wherein the X-ray low energy component absorbing material is a metal. 5. The metal is Cu, W, Mo, Ni, Pb, Au, A.
g, Ba, Ta, Fe, Al, Zn, Cd, Ti, Zr, V, Nb, Cr, Co
And at least one of Sn and X-ray photographic film-fluorescent intensifying screen-filter laminate according to claim 4.