JP2694582B2 - Method for determining radiation image reading condition and / or image processing condition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stimulable phosphor sheet,
Radiation image reading for obtaining reading conditions for photoelectrically reading a radiation image recorded on a recording sheet such as an X-ray film to obtain an image signal representing the radiation image, and image processing conditions for performing image processing on the image signal The present invention relates to a method for determining conditions and / or image processing conditions.

[0002]

2. Description of the Related Art A radiation image is accumulated and recorded on a recording sheet,
It is performed in various fields to read the recorded radiation image to obtain an image signal, perform appropriate image processing on the image signal, and then reproduce and record the image. For example,
An X-ray image is recorded by using an X-ray film having a low gamma value designed to be suitable for the subsequent image processing, and the X-ray image is read from the film on which the X-ray image is recorded and converted into an electric signal. By subjecting this electric signal (image signal) to image processing and reproducing it as a visible image on a copy photograph or the like, a reproduced image with good image quality performance such as contrast, sharpness, and graininess is obtained. There is
61-5193).

[0003] Further, the applicant of the present invention has proposed that radiation (X-ray, α
Radiation, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a portion of this radiation energy is accumulated, and then, when irradiated with excitation light, such as visible light, the accumulated light shows stimulated emission according to the accumulated energy. Using stimulable phosphor (stimulable phosphor)
Radiation image information of a subject such as a human body is once recorded on a sheet-shaped stimulable phosphor, and this stimulable phosphor sheet is scanned with excitation light such as laser light to generate stimulated emission light, and the obtained luminescence is obtained. A radiation image recording / reproducing system for photoelectrically reading exhaust emission light to obtain an image signal and outputting a radiation image of a subject on the basis of the image signal as a visible image on a recording material such as a photographic photosensitive material or a CRT has already been proposed. (Japanese Patent Laid-Open No.
55-12429, 56-11395, 55-163472, 56-104
No. 645, No. 55-116340, etc.).

[0004] This system has the practical advantage of being able to record images over a very wide radiation exposure area compared to conventional radiographic systems using silver halide photography. That is, in the case of the stimulable phosphor, it has been recognized that the amount of emitted light that is stimulated by excitation after accumulation is proportional to the radiation exposure amount over an extremely wide range. Even if fluctuates considerably, the amount of the stimulating light emitted from the stimulable phosphor sheet is read by the photoelectric conversion means with the reading gain set to an appropriate value and converted into an electric signal. Recording materials such as photographic photosensitive materials using
By outputting a radiation image as a visible image on a display device such as a CRT, it is possible to obtain a radiation image that is not affected by a change in radiation exposure.

In the above system, the stimulable phosphor sheet on which the radiation image is stored and recorded is first irradiated with a low-level light beam so that the reproduced image finally obtained is the best image. To obtain a pre-reading image signal by performing pre-reading to release a part of, and based on the pre-reading image signal,
Know the intensity of the radiation applied to this sheet, the dynamic range, etc., and then irradiate the sheet with a light beam of a higher level than the light beam used for the pre-reading to read the stored and recorded radiation image and obtain the image signal. There is a system configured to automatically determine the reading condition at the time of actual reading to be obtained or the image processing condition at the time of performing image processing on an image signal after the actual reading / reading (for example, Japanese Patent Laid-Open No. Sho-Kaiyo).
58-67242).

Here, the reading condition and the image processing condition are generic terms for various conditions at the time of reading and image processing, which affect the sensitivity and gradation of the reproduced image, respectively.
For example, it means gain, scale factor, light beam power, etc. in reading and scale conversion of image signal in image processing.

[0007] The high level / low level of the light beam means the magnitude of the energy of the light beam applied per unit area of the sheet or the energy of the photostimulated light emitted from the sheet, respectively. When it depends on the wavelength of the light beam (has a wavelength sensitivity distribution), the weight of the energy of the light beam irradiated per unit area of the sheet is weighted by the wavelength sensitivity. In other words, the method of changing the level of the light beam includes a method of using light beams of different wavelengths, a method of changing the intensity of a light beam emitted from a laser light source or the like, and inserting and removing an ND filter or the like on an optical path of the light beam. Known methods such as a method of changing the intensity of the light beam, a method of changing the scanning density by changing the beam diameter of the light beam, and a method of changing the scanning speed The method of people can be used.

Further, as described above, the method of preliminarily grasping the recording state and recording pattern of radiation image information and performing image processing on the image signal according to the grasped information does not use a stimulable phosphor sheet, It is also applicable and effective in the case of reading an image of a radiation image captured by a conventionally known silver halide photographic film or the like to obtain an image signal.

[0009]

In the above system, the reading conditions or the image processing conditions are determined so that each reproduced image is the best, and therefore it is not optimal to observe only each reproduced image. However, for example, when comparing the images of the same subject that were taken and saved in the past with the images of the current state and check the density change of both images, the conditions for image reading and image processing If the difference is different, it may be difficult to accurately grasp the degree of concentration change.

A concrete example of this problem is shown in FIG.
This will be described with reference to FIG.

FIG. 4 is a diagram showing a radiation image 66 of a part of the human body (front of the chest) reproduced and displayed on the photographic film 65. The normal portion 66b of the radiographic image 66 shows almost the same density, but only the diseased portion 66a has a lower density than the other portions.

FIG. 5 is a graph showing the degree of abnormal density of the diseased portion 66a when a plurality of radiation images of the subject shown in FIG. 4 are photographed, reproduced and recorded over time.
Over time, the disease is healing. Graph A shows an ideal line in which the concentration of the diseased part 66a should originally be reproduced in this way from the progress of the cure of the disease.
However, if the above reading and image processing are performed so that each reproduced image is optimized, the sick part
Due to the change in the density of 66a and other disturbance factors, the abnormal density of the diseased portion 66a in the finally reproduced image may be as shown in the graph B. In this case, the degree of lesion is judged by the difference between the concentration of the diseased portion 66a and the concentration of the normal portion 66b. That is, from the image captured at time T ₁ , what is to be determined as the original density difference ΔD ₁ (large density difference: considerably abnormal) as shown in graph A is shown in graph B.
As described above, there is a possibility that it may be judged that the concentration difference is ΔD ₁ ′ (small concentration difference: considerably cured). Further, from the image taken at time T ₂ , the density difference ΔD ₂ (ΔD ₂ <ΔD ₁ ) is originally supposed.
What should be judged is that the density difference ΔD ₂ ′ (ΔD ₂ ′> Δ
D ₁ ′), and at time T ₂ ,
The disease is in the direction of healing compared to time T ₁ ′ (Δ
Despite D ₂ <Δ ₁ D), there is a possibility that an erroneous diagnosis may be made as if the disease is progressing (ΔD ₂ ′> ΔD ₁ ′).

FIG. 6 is a diagram showing a radiation image 66 'of a part of the human body (the side of the lumbar vertebra) reproduced from the photographic film 65' and displayed, which is different from the one shown in FIG. When diagnosing a disease in which the density of the bone portion 66a ′ shown in the image 66 ′ appears to be high, the bone portion 66a ′ and the non-bone portion 66a ′
Different from the case of FIG. 4, b ′ is an organ different from each other, and therefore the difference in concentration between these two portions does not serve as the basis for the determination, and it must be determined by the concentration itself of the bone portion 66a ′.

However, when obtaining such a reproduced image,
Usually, the condition is set so that the image is reproduced so that the density of the bone portion 66a 'is constant.

FIG. 7 shows a case where a plurality of radiation images of the subject shown in FIG.
6 is a graph showing the degree of abnormal concentration in the bone portion 66a ′. As in the case of FIG. 5, over time the illness is in the direction of healing. The graph A'shows that the density of the bone portion 66a 'is
It shows the ideal line that should be reproduced in this way from the progress of the cure of the disease. However, as described above, when the reading and image processing are performed so that the bone portions 66a 'of the reproduced images one by one have the same density, the bone portions 66a'
The density of ‘
The reproduction is performed so that the density is almost the same as in the normal case, and in this case, it may be impossible to determine the abnormal density of the bone portion 66a '.

As means for solving the above problems,
Method of determining reading conditions and / or image processing conditions in consideration of the accumulated record information of the sheet on which the radiation images for follow-up observation reproduced in the past are recorded (Japanese Patent Application No. 2-250881), reading conditions and photographing The applicant has proposed a method (Japanese Patent Application No. 2-161594) in which the conditions are matched with the reading conditions and the imaging conditions of radiation images obtained in the past for the same subject.

However, the methods proposed in Japanese Patent Application Nos. 2-250881 and 2-161594 mentioned above are large in that the reading condition, the image processing condition and the photographing condition for a large number of subjects are stored. Since a storage device having a large capacity is required, the load on software and hardware constituting the above method is large, and a very large-scale device is required to implement the above method.

The present invention has been made in view of the above circumstances, and a radiation image reading condition and / or an image capable of obtaining a reproduced image suitable for comparative observation with a past reproduced image with a simple structure. It is intended to provide a method for determining processing conditions.

[0019]

[0020]

[0021]

[0022]

A first radiation image reading condition and / or image processing condition determining method of the present invention represents the radiation image by photoelectrically reading a radiation image of an object recorded on a recording sheet. In a method of determining a radiographic image reading condition and / or an image processing condition for obtaining a reading condition when obtaining an image signal and / or an image processing condition when performing image processing on the obtained image signal, the height of the patient as the subject , A weight, an age, a sex, and a chest thickness corresponding to at least two pieces of information of the reading condition and / or the latitude in the image processing condition are prepared for each of the at least two pieces of information. It is characterized in that the latitude is determined by referring to the standard table based on at least two pieces of information.

Further, a second radiation image reading condition and / or image processing condition determining method according to the present invention is the above-mentioned first radiation image reading condition and / or image processing condition determining method according to the present invention. And / or the sensitivity under image processing conditions is input from an external device.

A third radiation image reading condition and / or image processing condition determining method according to the present invention is the same as the first radiation image reading condition and / or image processing condition determining method according to the present invention. The radiation image of the subject is photoelectrically read to obtain a first image signal representing the radiation image, and a second image signal representing the radiation image is generated from the recording sheet based on the first image signal. It is characterized in that the sensitivity under the reading condition when obtaining is determined.

Here, the latitude corresponds to a light intensity ratio of the strongest stimulated emission light to the weakest stimulated emission light converted into an image signal at the time of reading, and the sensitivity is a predetermined light intensity. The photoelectric conversion rate that determines the level of the image signal of the stimulated emission light.

The radiation dose recorded on the recording sheet when capturing a radiation image varies depending on the physique of the patient who is the subject, and this physique of the patient is used when determining the reading conditions and the image processing conditions. It has an influence. The chest thickness is an important factor for determining reading conditions and image processing conditions because the chest size is optimal as a value representing the physical constitution of the patient. Therefore, it is preferable to estimate the physique of the patient based on the chest thickness information and determine the latitude under the reading condition and / or the image processing condition.

The first, second and third aspects of the present invention are also provided.
In the method of determining the radiographic image reading condition and / or the image processing condition, the latitude in the reading condition and / or the image processing condition is determined based on at least two pieces of information of height, weight, age, sex and chest thickness. However, like the above-mentioned chest thickness, this is suitable as a value indicating the physique of the patient whose height, weight, age, and sex are the subjects, and these information are important factors that determine the latitude. Because it has become.

Further, during the series of follow-up observations, the physique of the patient undergoing follow-up observations, that is,
Chest thickness, height, weight, etc. do not change so much. Therefore, in the present invention, the physical information as described above is used as an element for determining the latitude in the radiographic image reading condition and / or the image processing condition, and the same reading condition is always applied to a series of radiographic images of the same patient. The same image processing is performed by scanning.

The chest thickness here represents the thickness of the chest, and as the chest thickness increases, the chest circumference also increases. Therefore, in the present invention, the chest thickness and the chest circumference are treated as equivalent.

Further, here, there is a latitude corresponding to information such as chest thickness, which is optimal for patients with different physiques, such as fat patients with large chest thickness and thin patients with small chest size. It represents the latitude under the reading condition and / or the image processing condition such that various radiation images can be reproduced.

[0031]

The radiographic image reading condition and / or the image processing condition determining method according to the present invention is the information of the patient's chest thickness or the height, weight, age which is information that does not change so much during the follow-up period. , A standard table in which at least two pieces of information regarding sex and chest thickness, that is, latitude under reading conditions and / or image processing conditions corresponding to information about the physical constitution of the patient are stored for each of the physical constitution information described above, is prepared. Therefore, the latitude is determined by referring to this standard table based on the information on the physical constitution described above, and the reading condition and / or the image processing condition of the radiographic image are combined with the sensitivity input by another method or preset. I'm trying to decide. Therefore, by always reading the radiation image of the patient under the same reading condition and performing the same image processing, the radiation image of the same patient can always be obtained under the same condition, and accurate follow-up can be performed. .

Further, as the information used in the present invention, the amount of information of only the chest thickness of the patient or two of the chest thickness, height, weight, age and sex is not so large and can be easily obtained. Further, if only a standard table that associates these information with the latitude in the reading condition and / or the image processing condition is stored in the storage medium, the same condition will be obtained for patients of similar physical constitution. Therefore, it is not necessary to manage information about individual patients, and it is possible to determine the reading condition and / or the image processing condition by a simple system that does not require a large capacity storage medium.

[0033]

Embodiments of the present invention will be described below.

FIG. 1 is a block diagram showing the basic concept of the present invention.

The basic concept of the present invention corresponds to information that does not change much even during the period during which a series of radiation images of the same patient, that is, information on the patient's chest thickness, that is, information on the patient's physique, is being observed. The standard table 2 storing the latitude in the reading condition and / or the image processing condition is prepared, and the condition determining unit 3 refers to the standard table 2 and records it based on the information on the physical constitution of the patient input by the information input unit 1. The latitude is determined under the reading condition for reading the radiation image for follow-up observation of the patient recorded on the sheet and / or the image processing condition for performing the image processing on the read image. In addition, the latitude corresponding to this physique information is that there are various physique patients such as fat patients with large chest thickness and thin patients with small chest size, but for each patient with different physique It represents a latitude that can reproduce an optimum radiation image. That is, a patient with a large chest size has a large latitude, and a patient with a small chest size has a small latitude. Therefore, since a radiographic image is reproduced under the same condition for a patient having a similar physique, personal information does not have to be managed in the computer system including the present invention, and it is not necessary to use a large-capacity storage device.

FIG. 2 shows a radiation image information reading / reproducing system for reading and reproducing radiation image information from a stimulable phosphor sheet including a first embodiment of a method for determining a radiation image reading condition and / or an image processing condition according to the present invention. It is a thing.

First, the memory card 51 is inserted into the card recording / reading device 50 connected to the computer system 40. The computer system 40 includes a main body 41 having a built-in CPU and an internal memory, and a drive unit 4 into which a floppy disk as an auxiliary memory is inserted and driven.
2. A keyboard 43 for the operator to input necessary instructions and the like to the computer system 40 and a CRT display 44 for displaying the necessary information, and the memory of the computer system 40 stores the chest thickness of the patient. The standard table 2 in which a large number of latitudes corresponding to the above information is stored for each chest thickness information is stored. In addition, the memory card 51 is prepared for each patient (by subject name), and information regarding the chest thickness of the patient is recorded.

Next, the keyboard of the computer system 40
By operating 43, the patient's chest information recorded in the memory card 51, that is, the chest size is read.
Based on this chest thickness information, the computer system 40
By referring to the standard table 2 stored in the memory, the latitude under the reading conditions when the X-ray image is read by the reading means 100 is obtained, and is applied to the photomultiplier 23 according to this latitude and the predetermined sensitivity. The voltage value and the amplification factor of the logarithmic amplifier 26 are controlled.
Here, since the patient's chest thickness does not change so much during the series of follow-up observations, this latitude is the same as the latitude for reading an X-ray image in the series of follow-up observations in this patient. Will be the one.

When the reading conditions are determined as described above, the stimulable phosphor sheet 11 on which the X-ray image of the patient is stored and recorded is read by an X-ray imaging apparatus (not shown).

Accumulative phosphor sheet on which an X-ray image is recorded
11 is set at a predetermined position of the reading means 100. The stimulable phosphor sheet 11 set at this predetermined position is conveyed (sub-scanned) in the arrow Y direction by the sheet conveying means 15 such as an endless belt driven by a motor (not shown). On the other hand, a light beam 17 emitted from a laser light source 16 is reflected and deflected by a rotating polygon mirror 18 driven by a motor 24 and rotating at a high speed in the direction of an arrow, passes through a focusing lens 19 such as an fθ lens, and then an optical path is reflected by a mirror 20. Instead, the light is incident on the stimulable phosphor sheet 11 and the main scanning is performed in the arrow X direction substantially perpendicular to the sub-scanning direction (arrow Y direction). From the portion of the stimulable phosphor sheet 11 irradiated with this light beam 17,
A quantity of stimulated emission light 21 corresponding to the stored and recorded radiation image information is diverged, and this stimulated emission light 21 is guided by an optical guide 22 to a photomultiplier (photomultiplier tube).
Photoelectrically detected by 23. The light guide 22 is made by molding a light guide material such as an acrylic plate,
The linear incident end face 22a is arranged so as to extend along the main scanning line on the stimulable phosphor sheet 11, and the light receiving face of the photomultiplier 23 is coupled to the annular emitting end face 22b. There is. Light guide 22 from the incident end face 22a
The stimulated emission light 21 that has entered the inside travels through the light guide 22 by repeatedly undergoing total reflection, is emitted from the emission end face 22b and is received by the photomultiplier 23. The light quantity is converted into an electric signal by the photomultiplier 23.

The analog output signal S output from the photomultiplier 23 is logarithmically amplified by the logarithmic amplifier 26,
The image is digitized by the A / D converter 27 and an image signal _SQ is obtained. The signal level of the image signal S _Q is proportional to the logarithm of the amount of stimulated emission light emitted from each pixel of the stimulable phosphor sheet 11. As described above, the image signal S _Q is obtained under the reading condition determined by the computer system 40.

The image signal S _Q obtained by being digitized by the A / D converter 27 is input to the computer system 40 again. In the computer system 40, the same image processing conditions as when a series of past follow-up images for this patient were obtained based on the latitude obtained by referring to the standard table 2 based on the information on the patient's chest thickness. The predetermined image signal S _Q is subjected to appropriate image processing, and the image signal subjected to this image processing is sent to the reproduction means 29.
The reproducing means 29 reproduces and displays the X-ray image based on this image signal.

In the first embodiment, the sensitivity used when determining the condition is set to a predetermined value, but means for inputting the sensitivity is provided so that a predetermined value can be input from the outside. Good. For example, the sensitivity may be set in accordance with the radiation dose irradiated by the image capturing means and input to the computer system 40 in conjunction with the radiographic image capturing means (not shown), or may be input manually. .

Next, a second embodiment of the present invention will be described.

FIG. 3 shows a radiation image information reading / reproducing system for reading and reproducing radiation image information from a stimulable phosphor sheet including a second embodiment of the method for determining a radiation image reading condition and / or an image processing condition according to the present invention. It is a thing. This system is a system for performing the prefetch described above.

First, the memory card 51 is inserted into the card recording / reading device 50 connected to the computer system 40. This computer system 40 has a main body part in which a CPU and an internal memory are built in similarly to the first embodiment of the present invention.
41, a drive unit 42 into which a floppy disk as an auxiliary memory is inserted and driven, a keyboard 43 for an operator to input necessary instructions and the like to the computer system 40, and a CRT display 44 for displaying necessary information The memory of the computer system 40 stores a standard table 2 in which a large number of latitudes corresponding to the chest thickness information of the patient are stored for each chest thickness information. In addition, the memory card 51 is prepared for each patient (by subject name), and information regarding the chest thickness of the patient is recorded.

Next, the keyboard of the computer system 40
By operating 43, the patient's chest information recorded in the memory card 51, that is, the chest size is read.
Based on this chest thickness information, the computer system 40
By referring to the standard table 2 stored in the memory, the latitude of the reading conditions when reading the X-ray image is obtained as in the first embodiment of the present invention.

Accumulative phosphor sheet on which an X-ray image is recorded
First, 11 is set at a predetermined position of the pre-reading means 100 for performing pre-reading by scanning with a weak light beam to emit only a part of the radiation energy accumulated on the sheet 11. The structures of the pre-reading means 100 and the main reading means 100 'which will be described later are the same as those of the first embodiment of the present invention described above, and therefore detailed description thereof will be omitted.

The stimulable phosphor sheet 11 set at a predetermined position is read by the same method as in the first embodiment of the present invention and converted into an electric signal, which is logarithmically amplified by the logarithmic amplifier 26, and A / It is digitized by the D exchanging device 27, and the pre-read pixel signal Sp is obtained.

The pre-read image signal Sp thus obtained is input to the computer system 40. In the computer system 40, the sensitivity under the reading condition and / or the image processing condition is determined based on the preread image signal Sp. The calculation for obtaining the sensitivity under the reading condition and the image processing condition uses a known histogram (for example, JP-A-60-156055 and JP-A-60-156055).
-185944, 61-280163, 63-233658).

As described above, the reading conditions for the main reading,
That is, the sensitivity and the latitude are obtained, and the voltage value applied to the photomultiplier 23, the amplification factor of the logarithmic amplifier 26, and the like are controlled according to the sensitivity and the latitude.

Pre-reading storage phosphor sheet 11 '
Is set at a predetermined position of the main reading means 100 ', the sheet 11' is scanned by the light beam 17 'which is stronger than the light beam used for the pre-reading, and an image signal is obtained according to the reading conditions determined as described above. However, since the structure of the pre-reading means 100 ′ is substantially the same as the structure of the pre-reading means 100, that is, substantially the same as that of the first embodiment of the present invention, the constituent elements corresponding to the respective constituent elements of the pre-reading means 100 Is indicated by adding a dash to the number used in the prefetching means 100, and description thereof will be omitted.

The image signal S _Q obtained by being digitized by the A / D converter 27 'is input to the computer system 40 again. In the computer system 40, the same image processing conditions as when the series of past follow-up images in this patient were obtained are determined based on the latitude and sensitivity obtained as described above, and the image signal S _Q Is subjected to appropriate image processing, the image signal subjected to this image processing is sent to the reproducing means 29, and the reproducing means 29 reproduces and displays an X-ray image based on this image signal.

In the first and second embodiments, a memory card for recording information about each patient
51 is prepared, and based on the chest thickness information that does not change much during the series of follow-up observations, the latitude under the reading conditions and / or image processing conditions is determined by referring to the standard table 2, and a series of follow-up observations is performed. The image is read under the same reading condition as the above and image processing is performed under the same image processing condition. Therefore, it is possible to obtain a reproduction image suitable for comparative observation with a series of past observation images, and it is possible to grasp the progress of the lesion area of the patient, the treatment state, and the like.

In the first and second embodiments, the latitude under the reading condition and / or the image processing condition is determined based on the information about the patient's chest thickness, but the height, weight and year of the patient are determined. The latitude may be determined based on at least two pieces of information of age, sex, and chest thickness. In the present invention, since it is the information of the physical constitution of the patient that is necessary when determining the condition,
In this case, it is preferable that the height and the weight are included in at least two pieces of information.

In the first and second embodiments, the memory card 51 is prepared for each patient, and the card recording / reading device 50 reads the information about the patient's chest thickness. Needless to say, the chest thickness information of the patient may be input from the keyboard 43 of the computer system 40 without using the card recording / reading device 50.

Further, in the above-mentioned embodiment, the apparatus for reading the radiation image recorded on the stimulable phosphor sheet is explained, but the present invention is not limited to such an apparatus,
A device for reading a radiation image recorded on a conventional X-ray film, etc., photoelectrically reads light representing a radiation image obtained from a recording sheet on which a radiation image of a subject is recorded, to obtain an image signal, and to obtain this image signal. The present invention can be generally applied to a radiation image reading / reproducing apparatus that reproduces and outputs a radiation image based on the radiation image.

[0058]

As described in detail above, the present invention provides
Based on the information about the patient's physique that does not change much during the series of follow-up observations, the latitude under the same reading conditions and / or image processing conditions is always determined for the same patient, so follow-up A suitable radiographic image can be obtained, and the progress of the lesion area and the treatment state of the patient can be grasped.

Further, since it is not necessary to manage the personal information of the patient and it is not necessary to use a large-capacity storage device, the reading condition and / or the image processing condition can be determined by a simple system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic concept of the present invention.

FIG. 2 is an overall schematic diagram of a system using a condition determining method according to a first embodiment of the present invention.

FIG. 3 is an overall schematic diagram of a system using a condition determining method according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a radiation image of a human body reproduced and displayed.

5 is a graph showing the density of a part of an image when a plurality of radiation images of the subject shown in FIG. 4 are photographed, reproduced and recorded over time.

FIG. 6 is a diagram showing a radiation image of a human body reproduced and displayed.

7 is a graph showing the density of a part of an image when a plurality of radiation images of a subject shown in FIG. 6 are captured, reproduced and recorded over time.

[Explanation of symbols]

 11,11 'Accumulative phosphor sheet 21,21' Stimulated emission light 23,23 'Photomultiplier 26,26' Logarithmic amplifier 27,27 'A / D converter 40 Computer system 50 Card recording / reading device 51 Memory card 100, 100 'reading means

Claims (3)

(57) [Claims] 1. A reading condition for photoelectrically reading a radiation image of a subject recorded on a recording sheet to obtain an image signal representing the radiation image and / or an image processing for the obtained image signal. In a radiographic image reading condition and / or image processing condition determination method for obtaining image processing conditions, the reading condition and / or the reading condition corresponding to at least two information items of height, weight, age, sex, and chest thickness of the patient as the subject. Alternatively, a standard table storing a large number of latitudes in the image processing conditions for each of the at least two pieces of information is prepared, and the latitude is determined by referring to the standard table based on the at least two pieces of information. A method for determining a radiation image reading condition and / or an image processing condition. 2. The radiation image reading condition and / or image processing condition determining method according to claim 1, wherein the sensitivity of the reading condition and / or the image processing condition is input from an external device. 3. A radiation image of a subject recorded on the recording sheet is photoelectrically read to obtain a first image signal representing the radiation image, and the first image signal representing the radiation image is obtained. The radiation image reading condition and / or the radiation image reading condition according to claim 1, wherein the sensitivity under the reading condition when obtaining the second image signal representing the radiation image is determined.
Alternatively, a method for determining image processing conditions.