JPH0451229A - Condition deciding method for radiographic reading and reproducing method - Google Patents

Abstract

PURPOSE:To obtain a reproduced image suitable for comparative observation without using a step-wedge, etc., by making a photographing condition and a reading condition at the time of normal reading agree with those of a radiograph which are obtained in the past as to the same object in a system for performing the pre-reading. CONSTITUTION:A stimulable phosphor sheet 11 on which an X-ray image is recorded is scanned with a feeble light beam at first, then, pre-reading is performed by emitting some of radiation energies which are stimulated in the stimulable phosphor sheet 11, the light quantity of stimulated luminous light 19 for showing the radiograph is converted into an electric signal by a photo-multiplier 21, digitized by an A/D converter 27, and then, a pre-reading image signal SP is obtained. After obtaining the reading condition necessary for the normal reading, that means the sensitivity and the contrast at the time of the normal reading based on information inputted in a computer system 40, the stimulable phosphor sheet 11' whose pre-reading is finished is scanned with a stronger light beam 15' in a normal reading means 100', and an image signal SQ is obtained by the reading condition which is obtained. The signal SQ is inputted in the computer system 40, an optimum image processing is performed, and then, the X-ray image is reproduced and recorded on a film 91.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention captures and records radiation images on a recording sheet such as a stimulable phosphor sheet or an X-ray film, reads the radiation image from the recording sheet, and generates an image signal. The present invention relates to a radiographic imaging reading and reproducing method for obtaining a reproduced image based on the image signal.

(Prior Art) There are various methods of accumulating and recording radiation images on a recording sheet, reading the recorded radiation images to obtain an image signal, performing appropriate image processing on this image signal, and then reproducing and recording the image. It is carried out in the field of

For example, recording an X-ray image using a low gamma X-ray film designed to be compatible with subsequent image processing;
The X-ray image is read from the film on which it is recorded, converted into an electrical signal, and after image processing is applied to this electrical signal (image signal), the contrast is reproduced as a visible image in a copy photograph, etc. , reproduced images with good image quality performance such as sharpness and graininess have been obtained (see Japanese Patent Publication No. 81-5193).

In addition, the applicant has proposed radiation (X-rays, α-rays).

When irradiated with β rays, γ rays, electron beams, ultraviolet rays, etc., a part of this radiation energy is accumulated, and then when irradiated with excitation light such as visible light, stimulable fluorescence exhibits stimulated luminescence depending on the accumulated energy. Radiographic image information of a subject such as a human body is partially recorded on a sheet of stimulable phosphor using a stimulable phosphor, and this stimulable phosphor sheet is scanned with excitation light such as a laser beam. The resulting stimulated luminescent light is read photoelectrically to obtain an image signal, and based on this image signal, a radiation image of the subject can be recorded on recording materials such as photographic materials, CRTs, etc. A radiation image recording and reproducing system that outputs a visual image has already been proposed (Japanese Patent Application Laid-Open No. 1983-1989)
No.-12429, No. 5B-11395.

No. 55-163472, No. 56-104845, No. 55-116340, etc.).

This system has the practical advantage of being able to record images over a much wider range of radiation exposure compared to conventional radiographic systems using silver halide photography. In other words, in a stimulable phosphor, it is recognized that the amount of emitted light that is stimulated to emit light due to excitation after accumulation is proportional to the amount of radiation exposure over an extremely wide range.
Therefore, even if the amount of radiation exposure varies considerably due to various imaging conditions, the amount of stimulated luminescence emitted from the stimulable phosphor sheet can be read by the photoelectric conversion means by setting the reading gain to an appropriate value. By converting the radiation image into an electric signal and using this electric signal to output the radiation image as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT, a radiation image that is not affected by fluctuations in radiation exposure amount can be obtained. be able to.

In the above system, a low-level light beam is first irradiated onto the stimulable phosphor sheet on which the radiation image has been stored, so that the reproduced image finally obtained is the best image. A pre-read image signal is obtained by performing pre-reading to emit a pre-read image signal, and based on the pre-read image signal, the intensity, dynamic range, etc. of the radiation irradiated to this sheet are known, and then the light beam used for the pre-reading is applied to the above sheet. Automatically sets the reading conditions for actual reading to obtain an image signal by irradiating a higher level light beam and reading the stored radiation image, or the image processing conditions for performing image processing on the image signal after actual reading. There are systems configured to determine the
42).

Here, the reading condition 1 image processing condition is a general term for various conditions during the reading 1 image processing, which affect the sensitivity and gradation of the reproduced image, such as the gain in reading, the scale factor, This refers to the power of a light beam and the scale conversion of an image signal in image processing.

Also, the high level and low level of the light beam are, respectively.
If the energy of the light beam irradiated per unit area of the sheet or the energy of stimulated luminescence light emitted from the sheet depends on the wavelength of the light beam (has a wavelength sensitivity distribution), It refers to the weighting energy after weighting the energy of the light beam irradiated per unit area of the sheet with the wavelength sensitivity.As a method of changing the level of the light beam, light beams of different wavelengths are used. methods to use, methods to change the intensity of the light beam itself emitted from a laser light source, methods to change the intensity of the light beam by inserting or removing an ND filter, etc. on the optical path of the light beam, methods to change the beam diameter of the light beam. Various known methods can be used, such as a method of changing the scanning density and a method of changing the scanning speed.

There is also a system that analyzes the obtained image signal and determines the optimal image processing conditions for performing image processing on the image signal without performing this pre-reading. The method of determining the optimal image processing conditions based on this image signal is not limited to systems using stimulable phosphor sheets, and for example, image signals are obtained from radiation images recorded on recording sheets such as conventional X-ray films. It is also applied to the system.

(Problem to be solved by the invention) In each of the above systems, the reading conditions or image processing conditions are determined so that each reproduced image is the best, so it is optimal for observing only individual reproduced images. However, for example, when comparing an image taken and saved in the past of the same subject with an image taken of the current state and examining changes in density between the two images, it is necessary to read the image and process the image. If the conditions are different, a problem arises in that it may be difficult to accurately grasp the degree of concentration change.

A specific example of this problem will be explained with reference to FIGS. 3A to 3B and FIGS. 4A to 4B.

FIG. 3A is a diagram showing a radiographic image 6 of a part of the human body (the front of the chest) reproduced and displayed on the photographic film 5. The normal part 6b of this radiographic image 6 shows almost the same density, but the diseased part 6a has a lower density than the other parts.

FIG. 3B is a graph showing the degree of density abnormality in the diseased area 6a when a plurality of radiographic images of the subject shown in FIG. 3A are photographed, reproduced and recorded over time. Over time, the above-mentioned diseases are becoming more and more cured. Graph A shows an ideal line in which the concentration of the diseased area 6a should be regenerated in this manner based on the progress of healing of the disease. However, when the above reading and image processing are performed so that each reproduced image is optimized, the diseased part 6a
Due to density changes and other disturbance factors, the density abnormality of the diseased area 6a in the finally reproduced image may become as shown in graph B. In this case, the extent of the lesion is determined by the difference in density between the diseased area 6a and the normal area 6b. That is, from the image taken at time T1, the part that should originally be separated from the density difference ΔDl (density insertion: quite abnormal) as shown in graph A, is shown in graph B.
There is a risk that the concentration difference ΔD, (density left hand: considerably healed) may be determined. Furthermore, from the image taken at time T2, there is originally a density difference ΔDz (ΔD2 <
The concentration difference ΔD2 (
ΔD2 >ΔD1'), and time T2
In this case, there is a risk that an erroneous diagnosis may be made as if the disease is progressing (ΔD2 >ΔD1') even though the disease is in the direction of recovery (ΔD2 × ΔDI) compared to time T1'. There is.

Figure 4A shows the third image reproduced on the photographic film 5'.
Radiographic image 6 of a part of the human body (lumbar vertebrae side) different from Figure A
FIG. Bone part 6 shown in image 6'
When diagnosing a disease caused by a high concentration of a', the bone part 6a' and the part outside the bone mass 6b'
Unlike the case of FIG. 3A, since these two parts are different organs, the difference in density between these two parts is not a basis for judgment, and the judgment must be made based on the density of the bone part 8a' itself.

However, when obtaining such a reproduced image, conditions are usually set so that the image is reproduced so that the density of the bone portion 8a' is constant.

FIG. 4B is a graph showing the degree of density abnormality in the bone portion 6a' when a plurality of radiographic images of the subject shown in FIG. 4A are photographed, reproduced and recorded over time. As in the case of Fig. 3B, the disease progresses toward recovery over time. Graph A' shows an ideal line in which the density of the bone portion 6a' should be regenerated in this way based on the progress of disease healing. However, as described above, if the reading and image processing are performed so that the bone portions 6a' of each reproduced image have the same density, the bone portions 6a'
As shown in graph B', the concentration is reproduced to be between the normal case and the tract by removing disturbance factors, and in this case, it is impossible to determine whether there is an abnormal concentration in the bone part 6a'. There is a risk that this will happen.

One way to solve the above-mentioned problems is to record images of a staircase wedge with stepwise different radiation transmittances together with the subject image during radiography, and to record each step of the staircase wedge in the image to be compared and observed. A method has been proposed for setting reading conditions etc. so that the density of the image is the same as that of past images (see Japanese Patent Application Laid-Open No. 2-14378).
. However, with this method, it is necessary to always photograph and record the same stair wedge along with the subject, which poses problems in the management of the stair wedge and the workability of photographing. When determining the reading conditions based on the image signal (including the reading image signal), it is necessary to extract the image of the staircase wedge and determine the reading conditions based on the image signal values of each step, so this process determines the reading conditions, etc. The problem is that it becomes complicated.

In view of the above problems, the present invention provides a method for determining conditions in a radiation imaging reading and reproducing method, in which each condition is determined so as to obtain a reproduced image that can be observed in comparison with a past reproduced image, without using a step wedge or the like as a reference. The purpose is to provide a method.

(Means for Solving the Problems) One aspect of the present invention is applied to a system that performs so-called pre-reading using the above-mentioned stimulable phosphor sheet. That is, the first condition determining method of the present invention is a radiation method in which a radiation image of the subject is recorded on the stimulable phosphor sheet by irradiating the subject with radiation and irradiating the radiation that has passed through the subject onto the stimulable phosphor sheet. A first image signal representing the radiation image is obtained by performing imaging, irradiating the stimulable phosphor sheet with excitation light and reading the stimulated luminescence light emitted from the stimulable phosphor sheet, and obtaining the first image signal representing the radiation image. Based on the first image signal, the stimulable phosphor sheet is irradiated with excitation light again and the stimulated luminescent light emitted from the stimulable phosphor sheet is read to obtain a second image signal representing the radiation image. A post-reading second image is obtained by determining reading conditions for main reading, performing reading according to the reading conditions, and performing image processing as necessary on the second image signal obtained by the main reading. In the method for determining the conditions for determining the imaging conditions for the radiography and the reading conditions for the actual reading in the radiographic imaging reading and reproducing method that outputs a reproduced image based on a signal, the radiography conditions for the radiography performed in the past; The information for mutually identifying the objects in the radiography and the reading conditions for the main reading in the reading performed in the past are stored in a storage means in association with each other, and the radiography and the reading of the desired subject are performed. When performing this, a search is made to determine whether or not the radiography and reading were performed on the same subject as the desired subject in the past, and the radiography and reading were performed on the same subject as the desired subject in the past. If the imaging conditions have been executed, the imaging conditions are adjusted to the imaging conditions used for the radiation imaging of the same subject, and the reading conditions are determined based on the first image signal. The present invention is characterized in that the radiographic imaging and the reading of the desired subject are performed by adjusting the reading conditions for the actual reading of the radiographic image of the subject.

Another aspect of the present invention is that it is not limited to a stimulable phosphor sheet, and may be any recording sheet on which radiation images are photographed and recorded. That is, the second condition determining method of the present invention is to perform radiography in which a radiographic image of the subject is recorded on a recording sheet by irradiating the subject with radiation and irradiating the recording sheet with the radiation that has passed through the subject, and The radiation image recorded on the recording sheet is read photoelectrically to obtain an image signal representing the radiation image, and based on the image signal obtained by the reading, a desired image signal is selected from among the image signals. Determine standardization conditions when performing standardization to extract only image signals carrying image information, perform the standardization according to the standardization conditions, and apply as necessary to the image signal extracted by the standardization. In the condition determination method for determining the imaging conditions during the radiography and the normalization conditions during the standardization in the radiographic imaging reading and reproducing method that outputs a reproduced image based on a post-read image signal subjected to image processing, The imaging conditions of the radiography performed, the information for mutually identifying the subjects in the radiography, and the standardization conditions of the standardization performed in the past are stored in a storage means in association with each other, and are stored as desired. When performing the radiography, reading, and standardization of a subject, it is searched whether or not the radiography, reading, and standardization have been performed on the same subject as the desired subject in the past. , when the radiography, the reading, and the standardization have been performed for the same subject as the desired subject in the past, adjusting the radiography conditions to the radiography conditions for the radiography of the same subject; At the same time, instead of determining the normalization condition based on the image signal, the normalization condition is adjusted to the normalization condition used in the normalization of the image signal of the same subject, and the radiation of the desired subject is determined. The present invention is characterized in that photographing, the reading, and the standardization are executed.

Here, the storage means in the first and second condition determination methods may be one that centrally records information on a large number of subjects, or may be composed of a large number of storage media that are separate from each other. good. In the case where the image forming apparatus is composed of a large number of mutually separate storage media, it is preferable to prepare a storage medium for each subject name among the information for identifying the subject.

(Function) The present invention is advantageous in that in a system that performs pre-reading, the imaging conditions and the reading conditions for main reading are made to match those of radiation images obtained in the past for the same subject, and in systems that do not perform pre-reading. Since the imaging conditions and normalization conditions were matched with those of radiographic images of the same subject obtained in the past, it is possible to obtain reconstructed images suitable for comparative observation without using a step wedge or the like.

Here, if information regarding past images is recorded in a number of storage media that are configured separately for each subject name, it is possible to centrally store information corresponding to the subject name using a node disk device or the like. Compared to the case where a large number of subjects are recorded, there are advantages in that the device can be configured simply because it does not require a large capacity storage device and there is less information exchanged online. If you centrally store information about your computer, it has the advantage of preventing you from losing one or some of the many storage media, so any of these can be used. .

(Example) Examples of the present invention will be described below.

FIG. 1 is an overall schematic perspective view of an example of a system using the condition determination method of the present invention. Here, a system that performs pre-reading using a stimulable phosphor sheet will be described.

First, a memory card 51 is inserted into the card recording/reading device 50, and by operating the keyboard 43 of the computer system 40, the contents recorded on this memory card 51 are read, and new information is recorded on this memory card 51. Ru. This memory card is prepared for each patient (subject name and interest), and in the case of a first consultation, a new memory card 51 is inserted, and since nothing is recorded on this memory card 51, it is recognized that it is a first consultation. . Information about the subject, such as the subject name, is input from the keyboard 43.
sex.

The name of the disease, the area to be imaged, etc. are input, and in the case of a first visit, these inputted information are recorded on the memory card, and from this information, the imaging conditions when performing X-ray photography with the X-ray imaging device 1, such as the X-ray tube 2, are determined. The tube voltage (determines radiation quality) and irradiation time (determines dose) are determined. In addition, in the case of a re-examination, the already created patient memory card 51 is inserted into the card recording/reading device 50, which recognizes that the previous imaging has already been performed, and sets the same imaging conditions as the previous one. . Even in the case of a re-examination, if a diagnosis is requested for a disease different from the previous diagnosis, that fact is input from the keyboard 43 and new imaging conditions are determined.

After the above preparations are completed, the X-ray imaging apparatus 1 then performs X-ray imaging of the subject. X of this X-ray imaging device 1
X-rays 3 or the chest 4a of the human body 4 are irradiated from the ray tube 2, and the X-rays 3a that have passed through the human body 4 are transmitted to the stimulable phosphor sheet 11.
A transmitted X-ray image of the chest 4a of the human body is accumulated and recorded on the stimulable phosphor sheet ll.

The stimulable phosphor sheet 11 on which an X-ray image has been recorded is first scanned with a weak light beam to emit only a portion of the radiation energy stored in the stimulable phosphor sheet 11, thereby performing pre-reading. 100 predetermined positions. The stimulable phosphor sheet 11 set in this predetermined position
is transported (sub-scanning) in the direction of arrow Y by a sheet transport means 13 such as an endless belt driven by a motor 12. On the other hand, a weak light beam 15 emitted from a laser light source 14 is reflected and deflected by a rotating polygon mirror 16 that is driven by a motor 23 and rotates at high speed in the direction of the arrow.
After passing through a converging lens 17 such as a lens, the optical path is changed by a mirror 18, and the light enters the stimulable phosphor sheet 11 for main scanning in the direction of arrow X, which is substantially perpendicular to the direction of sub-scanning (direction of arrow Y). This light beam 1 of the stimulable phosphor sheet 11
5 is irradiated, a stimulated luminescent light 19 is emitted in an amount corresponding to the radiographic image information stored and recorded, and this stimulated luminescent light 19 is guided by a light guide 20 to a photomultiplier (photoelectronic is detected photoelectrically by a multiplier tube) 21. The light guide 20 is made by molding a light-guiding material such as an acrylic plate, and is arranged so that the linear entrance end surface 20a extends along the main scanning line on the stimulable phosphor sheet 11. The light receiving surface of the photomultiplier 21 is coupled to the annularly formed exit end surface 20b. The light guide 20 from the incident end surface 20a
The stimulated luminescent light 19 that has entered the light guide 20 travels through the interior of the light guide 20 through repeated total reflection, exits from the exit end face 20b, and is received by the photomultiplier 21, where the stimulated luminescent light 19 representing a radiation image is generated. Light intensity is photo multiplier 2
1 into an electrical signal.

The analog output signal S output from the photomultiplier 21 is logarithmically amplified by a logarithmic amplifier 26 and digitized by an A/D converter 27 to obtain a pre-read image signal SP. The signal level of this pre-read image signal S is proportional to the logarithm of the amount of stimulated luminescence light emitted from each pixel of the stimulable phosphor sheet 11.

In the above-mentioned pre-reading, reading conditions, such as the voltage value applied to the photomultiplier 21 and the amplification factor of the logarithmic amplifier 26, are determined so that the radiation energy accumulated in the stimulable phosphor sheet 11 can be read over a wide range. It is being

The obtained pre-read image signal SP is sent to the computer system 4.
It is input to 0. This computer system 40 is
Main body section 41 with built-in PU and internal memory. A drive section 42 into which a floppy disk as auxiliary memory is inserted and driven. It comprises a keyboard 43 for an operator to input necessary instructions to the computer system 40, and a CRT display 44 for displaying necessary information.

Card reading/recording device fi50 to computer system 4
Based on the information entered in 0, if it is recognized that this subject (patient) is seeing the patient for the first time, the reading conditions for main reading, that is, the sensitivity and contrast for main reading, are calculated, and this sensitivity, latitude, etc. Accordingly, for example, the voltage value applied to the photomultiplier 21' and the logarithmic amplifier 2
6' amplification factor etc. are controlled.

Contrast here corresponds to the light intensity ratio of the strongest stimulated luminescence light to the weakest stimulated luminescence light that is converted into an image signal during main reading, and sensitivity corresponds to the ratio of the luminous intensity of the most intense stimulated luminescence light to the weakest stimulated luminescence light that is converted into an image signal during main reading. This refers to the photoelectric conversion rate that determines what level of image signal the emitted light is converted to.

FIG. 2 is a diagram showing an example of a histogram of the pre-read image signal SP. The horizontal axis represents each value of the pre-read image signal SP, and the vertical axis (
(Upper) represents the appearance frequency of the pre-read image signal of each value. In addition, the vertical axis (downward) is the image signal S obtained from the main reading.
It represents Q.

An example of how to obtain reading conditions for main reading will be explained using this diagram.

The histogram 70 corresponds to a peak 70a formed from a pre-read image signal representing the subject image and a direct X-ray portion formed by the X-rays directly irradiating the stimulable phosphor sheet without passing through the subject. It is formed from the mountain 70b. In this case, only the image signal corresponding to the subject image is required for the actual reading. Therefore, at the threshold value T, from the smaller value (left side) of the pre-read image signal SP to the larger value (
The pre-read image signals SP1+S P2 corresponding to the point a that first intersects with the histogram 70 and the point A that intersects the second intersect with the histogram 70 are obtained, and these pre-read image signals SP1+ SF3 are The reading conditions for the actual reading are determined so as to correspond to the minimum image signal SQl+the maximum image signal SQ2 during the actual reading, that is, along the straight line G. The reading conditions for the main reading determined in this manner are recorded in the memory card 51 by the card reading/recording device 5o.

In addition, when the subject (patient) is not seen for the first time, instead of determining the reading conditions for the main reading based on the pre-read image signal Sp as described above, the main reading used in the previous imaging/reading from the memory card 51 can be used. The reading conditions are read out.

When the reading conditions for main reading are determined in this way or are read from the memory card 51, the stimulable phosphor sheet 11' for which pre-reading has been completed is set at a predetermined position of main reading means 100', and the pre-reading is performed. The beam 11' is scanned by a light beam 15' that is stronger than the used light beam, and an image signal S0 is obtained under the reading conditions determined as described above. Since there is a difference between the configuration of 100 and the path, the pre-reading means 10
Pre-reading means 100 is provided for each component of 0 and the corresponding component.
The numbers used in the above are shown with a dash and the explanation is omitted.

The image signal SQ obtained by being digitized by the A/D converter 27' is sent to the computer system 40 again.
is input. Appropriate image processing is performed on the image signal SQ within the computer system 40, and the image signal subjected to this image processing is sent to a laser printer 90, where an X-ray image based on this image signal is printed on a film 91. is played back and recorded.

In the above embodiment, a memory card 51 is prepared for each patient to record information about that patient, and in the case of a re-examination, the image is taken under the same imaging conditions as the previous time of imaging, reading, replaying, and recording. Since the reading is performed under the following reading conditions, it is possible to obtain a reproduced image suitable for comparison and observation with the previously obtained reproduced image. In the case of a first visit, the imaging conditions and reading conditions are set so that the X-ray image itself provides the best reconstructed image.

In the above embodiment, a memory card 51 is prepared for each patient, which eliminates the need for a large-capacity storage device, and simplifies the system by reducing the number of online exchanges of information. memory card 5
1 may be lost, a large-capacity storage device 52 such as a hard disk may be provided to centrally manage information on a large number of patients.

Further, in the above embodiment, the pre-reading means 1oo and the main reading means 10
0' are configured separately, but as mentioned above, the configuration of the pre-reading means 100 and the main reading means 100' is between the two, so it is possible to integrate the pre-reading means 100 and the main reading means 100'. May also be used for both purposes. In this case, after pre-reading, the stimulable phosphor sheet 11 may be moved back once and then scanned again to perform main reading.

When the pre-reading means and the main reading means are used, it is necessary to switch the intensity of the light beam between the pre-reading and the main reading. Various methods can be used, such as a method of switching the intensity itself.

Further, in the above embodiment, a system for adjusting the reading conditions during main reading has been described, but during main reading, reading can be performed under predetermined reading conditions regardless of the pre-read image signal SP or regardless of the previous shooting. In the case of a first consultation, the computer system 4o extracts only the signal corresponding to the desired subject image from the image signal sQ based on the pre-read image signal S, and sends the extracted signal to the laser printer 9o. In addition, in the case of a re-examination, this image processing condition may be read out from the memory card 51, and both the reading condition and the normalization condition may be determined. may also be managed.

Furthermore, although the above embodiment has been described with respect to a system that performs pre-reading, the present invention can also be applied to a system that immediately performs reading equivalent to the above-mentioned main reading without performing pre-reading. In this case, when reading, an image signal is obtained by reading under predetermined reading conditions, and based on this image signal, standardization conditions are determined within the computer system 40, and the memory card 51 stores the standardization conditions. is recorded and read out, and the image signal is standardized according to the standardization conditions.

(Effects of the Invention) As explained in detail above, the present invention uses the same conditions for both photographing conditions and reading conditions as when the previously reproduced image was obtained, so there is no need to use a step wedge or the like. A reproduced image suitable for comparison observation with the previously obtained reproduced image can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic perspective view of an example of a system using the condition determination method of the present invention, Fig. 2 is a diagram showing an example of a histogram of a pre-read image signal, and Fig. 3A is a diagram showing an example of a histogram of a pre-read image signal. Figure 3B is a diagram showing a radiation image of a human body. Figure 3B is a graph showing the density of a portion of the image when multiple radiation images of the subject shown in Figure 3A are photographed, reproduced and recorded over time. Figure 4A 4B is a diagram showing a radiation image of a human body reproduced and displayed in the same way as FIG. 3A, and FIG. 4B is a diagram showing a plurality of radiation images of the subject shown in FIG. 7 is a graph showing the density of a portion of an image when it is reproduced and recorded. 1... X-ray imaging device 2... X-ray tube 11.11
'... Stimulable phosphor sheet 19.19 '... Stimulated luminescent light 21.21 '... Photo multiplier 26.2
6'...Logarithmic amplifier 27.27'...A/D converter 40...Computer system 50...Card recording/reading device 51...Memory card 52...Magnetic disk 90...Laser Printer 100...prereading means 1
00'... Book reading means 4 poor Figure 3A Figure 3B

Claims (4)

[Claims] (1) Performing radiography in which a radiation image of the subject is recorded on a stimulable phosphor sheet by irradiating a subject with radiation and irradiating the radiation that has passed through the subject onto a stimulable phosphor sheet, and the stimulable fluorescence A first image signal representing the radiation image is obtained by irradiating the body sheet with excitation light and reading the stimulated luminescence light emitted from the stimulable phosphor sheet, and based on the first image signal, the irradiating the stimulable phosphor sheet with excitation light again and reading the stimulated luminescence light emitted from the stimulable phosphor sheet to obtain a second image signal representing the radiation image; determining the reading conditions for main reading; A radiation source that performs reading according to the reading conditions, performs image processing on the second image signal obtained by the actual reading, and outputs a reproduced image based on the second image signal. In the condition determining method for determining the imaging conditions for the radiography and the reading conditions for the main reading in the image capture reading and playback method, the imaging conditions of the radiography performed in the past and the subject in the radiography are mutually identified. The information and the reading conditions of the main reading in the reading performed in the past are stored in a storage means in association with each other, and when performing the radiography of the desired subject and the reading, A search is made to determine whether or not the radiography and the reading have been performed on the same subject as the desired subject, and if the radiography and the reading have been performed on the same subject as the desired subject in the past, the radiography and the reading are performed on the same subject as the desired subject. The conditions are adjusted to the imaging conditions for the radiation imaging of the same subject, and instead of determining the reading conditions based on the first image signal, the main reading of the radiographic image of the same subject is adjusted. 1. A method for determining conditions in a radiographic imaging reading and reproducing method, characterized in that the radiographic imaging and the reading of the desired subject are performed by adjusting the reading conditions to the actual reading conditions. (2) Performing radiography in which a radiographic image of the subject is recorded on a recording sheet by irradiating the subject with radiation and irradiating the radiation that has passed through the subject onto a recording sheet, and the radiographic image recorded on the recording sheet. photoelectrically reading to obtain an image signal representing the radiation image, and based on the image signal obtained by the reading, select only the image signal carrying desired image information from among the image signals. Find standardization conditions when performing standardization to be extracted, execute the standardization according to the standardization conditions, perform image processing as necessary on the image signal extracted by the standardization, and then process the image signal. In the method for determining the conditions for determining the imaging conditions for the radiography and the normalization conditions for the standardization in the radiography reading and reproducing method that outputs a reproduced image based on the radiography, the radiography conditions for the radiography performed in the past. , the information for mutually identifying the objects in the radiography, and the standardization conditions of the standardization carried out in the past are stored in a storage means in association with each other, and the radiography of the desired subject, the reading, In executing the standardization, it is searched whether or not the radiography, the reading, and the standardization have been performed on the same subject as the desired subject in the past; When the radiography, the reading, and the standardization have been performed on the same subject, adjusting the radiography conditions to the radiography conditions for the radiography of the same subject, and adjusting the standardization conditions, Instead of determining based on the image signal, the radiography, the reading, and the standardization of the desired subject are adjusted to the standardization conditions used in the standardization of the image signal of the same subject. 1. A method for determining conditions in a radiographic imaging reading and reproducing method, characterized by carrying out the following: (3) The method for determining conditions in a radiographic imaging reading and reproducing method according to claim 1 or 2, wherein the storage means records information on a large number of subjects in a concentrated manner. (4) The information identifying the subject includes information identifying the name of the subject and information identifying the part of the subject targeted for imaging in the radiography, and the storage means prepares information for each subject name. 3. The method for determining conditions in a radiographic imaging reading and reproducing method according to claim 1, wherein the method comprises a plurality of mutually separate storage media.