JP6744749B2 - Radiation imaging apparatus, radiation imaging system, radiation imaging method, and program - Google Patents

Description

The present invention relates to a radiation imaging apparatus, a radiation imaging system, a radiation imaging method, and a program.

The X-ray CT apparatus developed in the 1970's has since become popular and advanced. The X-ray CT apparatus includes an X-ray source (radiation generation unit) and a detection unit that is arranged to face the X-ray source with the subject interposed therebetween, and the X-ray source and the detection unit rotate about the subject. By measuring the X-ray, the X-ray transmitted through the subject is measured at various angles. Then, based on the information obtained from the measurement result, a spatial distribution of the linear attenuation coefficient of the subject is obtained by reconstructing the image of the subject using a method such as the Filtered Back Projection (FBP) method. be able to.

In the CT device, the spatial distribution of the linear attenuation coefficient of the subject is obtained by measuring how much the radiation emitted from the radiation source (radiation generation unit) is attenuated while traveling straight in the subject. In this case, since the radiation scattered by the subject is mixed and measured, the accuracy of the reconstruction of the spatial distribution of the linear attenuation coefficient decreases. Therefore, it is necessary to estimate the scattered rays to be mixed and remove them from the measured amount.

For example, Patent Document 1 discloses a method of speeding up scattered ray estimation by using a common scattered ray distribution for n adjacent projection directions (see Patent Document 1).

Japanese Patent No. 4357612

However, the method disclosed in Patent Document 1 has a problem that a means for shielding scattered rays is required.

One form of radiation imaging apparatus according to the present invention was irradiated in a state of arranging a first measuring means for measuring a first detection data of the radiation emitted in a state that does not place a subject, the subject Second measurement means for measuring the second detection data of the radiation, and the first scattering of the radiation in a range other than the projection range of the subject based on the first detection data and the second detection data. A first estimating means for estimating the line distribution ,
It said first estimation means, the second detection data is greater extent than the first detection data, you defined as a range other than the projection range.

According to the radiation imaging apparatus of the present invention, it is possible to estimate scattered radiation even when there is no means for shielding scattered radiation.

It is a figure which shows an example of a structure of the radiography system which concerns on 1st Embodiment. It is a flow chart which shows an example of a processing flow of a radiography system concerning a 1st embodiment. It is a figure which shows an example of the detection data which the detection part detected. It is a figure which shows an example of 1st scattered radiation distribution. It is a figure which shows an example of a structure of the radiography system which concerns on 2nd Embodiment. It is a flow chart which shows an example of a processing flow of a radiography system concerning a 2nd embodiment. It is a figure which shows an example of the 2nd scattered ray distribution which concerns on 2nd Embodiment. It is a figure which shows an example of a structure of the radiography system which concerns on 3rd Embodiment. It is a flow chart which shows an example of a processing flow of a radiography system concerning a 3rd embodiment. It is a figure showing an example of a plurality of scattered radiation distributions of the whole field.

(First embodiment)
The first embodiment of the present invention will be described, and an embodiment that can estimate scattered rays even when there is no means for shielding scattered rays will be described. A first embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of a radiation imaging system according to this embodiment. FIG. 2 is a flowchart showing an example of the processing flow of the radiation imaging system according to this embodiment.

The radiation imaging system includes a radiation generation unit 101, a detection unit 104, a first measurement unit 105, a second measurement unit 106, an estimation unit (first estimation unit) 107, and a display unit 110. The radiation generation unit 101 includes a radiation generation source. In this embodiment, the radiation is X-rays, but it may be α rays, β rays, heavy particle rays, or γ rays.

The radiation generation unit 101 irradiates the subject 102 with radiation 103. In the present embodiment, the subject 102 is a living body, but a subject other than a living body such as an industrial product may be the subject. The detection unit 104 is arranged to face the radiation generation unit 101 with the subject 102 interposed therebetween, and detects the radiation 103 from the radiation generation unit 101.

In the present embodiment, the detection unit 104 uses a flat panel detector (Flat Panel Detector (FPD)) formed of a semiconductor material and in which many detection elements are arranged in a lattice, but a line sensor or the like may be used.

The first measurement unit 105 measures the first detection data of the radiation 103 applied without the subject 102 being placed. The second measurement unit 106 measures the second detection data of the radiation 103 applied with the subject 102 placed.

In FIG. 1, the first measuring unit 105 and the second measuring unit 106 are illustrated as different devices for convenience of description, but the first measuring unit 105 and the second measuring unit 106 are not illustrated. It is preferable that they are realized by the same device. This is because it is preferable that among the measurement conditions of the first measurement unit 105 and the second measurement unit 106, only the presence or absence of the subject is different, and the other measurement conditions are the same.

The information measured by the detection unit 104 is sent to the estimation unit 107 and processed. The estimation unit (first estimation unit) 107, based on the first detection data and the second detection data, the first scattered radiation distribution of the radiation 103 in a range (non-projection range) other than the projection range of the subject 102. To estimate. The estimation unit (first estimation unit) 107 estimates the first scattered radiation distribution from the difference between the first detection data and the second detection data. For example, the estimation unit (first estimation unit) 107 estimates the first scattered radiation distribution by subtracting the first detection data from the second detection data.

In the present embodiment, the estimation unit 107 shows an example of a program executed by a computer. The estimating unit 107 may be an integrated circuit as long as the same function is achieved, and the estimating unit 107 is not limited to the form.

The display unit 110 displays the result obtained by this embodiment. For example, the display unit 110 is a liquid crystal display, a CRT, or the like. In addition, the display unit 110 may be one that can be visually recognized by humans.

Next, the operation of the configuration of FIG. 1 and the estimation of scattered radiation will be described using the flowchart of FIG.

First, in step S205, the first detection data measuring step is executed. In this step, the radiation 103 is emitted and measured in a state where the subject 102 is not placed, and the measurement information A (first detection data) is obtained by the first measurement unit 105.

FIG. 3 is a diagram showing an example of the detection data detected by the detection unit 104 in association with the presence or absence and the arrangement of the subject 102. The horizontal axis is the detection position, and the vertical axis is the measured value. An example of the measurement information A is shown as the first detection data 305. In this embodiment, the first detection data 305 has the same measurement value regardless of the detection position.

Next, in step S206, the second detection data determination step is executed. In this step, the radiation 103 is emitted and measured while the subject 102 is placed, and the measurement information B (second detection data) is obtained by the second measurement unit 106. An example of the measurement information B is shown as the second detection data 306. In FIG. 3, the subject 102 is spherical. Since the radiation 103 emitted from the radiation generation unit 101 is attenuated by the subject 102, there is a detection position where the second detection data 306 shows a smaller value than the first detection data 305.

Next, in step S207, the scattered radiation distribution estimation process of a non-projection range is performed. In this step, the estimation unit 107 estimates the scattered radiation distribution C (first scattered radiation distribution) in a region (non-projection range of the subject 102) that does not shade the subject 102.

For example, in the non-projection range R, the non-projection range R is defined as a detection position in which the value of the measurement information B (second detection data) is larger than the value of the measurement information A (first detection data). A value obtained by subtracting the value of the measurement information A from the value of the measurement information B is estimated as the value of the scattered radiation distribution C. The estimation unit (first estimation unit) 107 estimates the scattered radiation distribution C (first scattered radiation distribution) by subtracting the first detection data from the second detection data.

This will be described in detail with reference to FIG. In FIG. 3, the measurement information A is the first detection data 305, and the measurement information B is the second detection data 306. At the detection position where the radiation 103 is attenuated by the subject 102, the second detection data 306 has a smaller value than the first detection data 305, but in the surroundings, the second detection data 306 is the first detection data 306. There is a detection position that has a larger value than the data 305.

The estimation unit 107 defines a range in which the second detection data 306 is larger than the first detection data 305 as a range (non-projection range) R other than the projection range.

One reason that the second detection data 306 has a larger value than the first detection data 305 is that the X-rays (radiation) 103 scattered by the subject 102 are detected in the vicinity of the subject 102. .. That is, the increment by which the second detection data 306 has a larger value than the first detection data 305 indicates the scattered dose. Therefore, in the non-projection range R, the scattered radiation distribution C (first scattered radiation distribution) can be estimated by subtracting the first detection data from the second detection data.

FIG. 4 is a diagram showing an example of the scattered radiation distribution C. The horizontal axis is the detection position corresponding to FIG. 3, and the vertical axis is the scattered dose. The first scattered radiation distribution 407 is calculated by subtracting the first detection data 305 from the second detection data 306 in the non-projection range R.

It was stated that one reason that the second detection data 306 has a larger value than the first detection data 305 is scattered radiation. However, in general, the mixing of other noises may be the reason for this, and therefore the threshold value (noise data) of the measurement value corresponding to noise may be defined in advance.

In this case, the estimation unit 107 may define the detection position where the value obtained by subtracting the first detection data 305 from the second detection data 306 exceeds a predetermined threshold value (noise data) as the non-projection range R. The estimation unit (first estimation unit) 107 subtracts the first detection data 305 from the second detection data 306 in the non-projection range R to obtain the scattered radiation distribution C (first scattered radiation distribution). presume.

As described above, various variations can be considered in the definition of the non-projection range R and the calculation of the scattered radiation distribution C.

In addition, the display unit 110 displays the first detection data, the second detection data, the first scattered radiation distribution, and a predetermined threshold value (noise data) as necessary. This allows the operator to confirm and evaluate the processing result.

According to this embodiment, it is possible to estimate scattered rays in a range other than the projection range (non-projection range) even if there is no means for shielding scattered rays.

(Second embodiment)
Next, a second embodiment of the present invention will be described, and an embodiment in which the scattered radiation distribution estimated in the non-projection range is used to correct the scattered radiation distribution in the entire region (projection range and non-projection range) explain. Note that description of the same configurations, functions, and operations as those of the above-described embodiment will be omitted, and differences from the present embodiment will be mainly described. A second embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 5: is a figure which shows an example of a structure of the radiography system which concerns on this embodiment. FIG. 6 is a flowchart showing an example of the additional processing flow of the radiation imaging system according to this embodiment.

The present embodiment is an example in which the configuration and the processing flow are added to the configuration and the processing flow in the first embodiment. The additional configuration will be described with reference to FIG. The additional components are an estimation unit (second estimation unit) 508 and a correction unit 509. In the present embodiment, the estimation unit 508 and the correction unit 509 are examples of programs executed by a computer. It may be an integrated circuit as long as it has a similar function, and is not limited to the form.

Next, the operation of the configuration of FIG. 5 and the estimation of scattered radiation will be described with reference to the flowcharts of FIGS.

First, in the present embodiment, as in the first embodiment, the flowchart of FIG. 2 is executed to estimate the scattered radiation distribution C in the region (non-projection range) that does not become the shadow of the subject 102.

Next, in step S608 of FIG. 6, the estimation unit (second estimation unit) 508 executes the scattered radiation distribution estimation process for the entire region. In this step, one scattered radiation distribution D (second scattered radiation distribution) is estimated for a region (projection range) where the subject is shaded and a region (non-projection range) where the subject is not shaded (non-projection range). Here, the projection range is a complement of the non-projection range. Therefore, the entire area includes the projection range and the non-projection range. In this step, the scattered radiation distribution D in the projected range and the non-projected range is estimated.

The estimation unit (second estimation unit) 508 scatters the radiation 103 in the projection range and the non-projection range based on the detection data (second detection data) of the radiation 103 irradiated with the subject 102 placed. Estimate the line distribution D (second scattered ray distribution).

A known technique can be applied as a method of estimating the scattered radiation distribution D in the entire region. For example, in the case of a CT apparatus, as shown in Japanese Patent No. 5052281, using the path length of scattered rays passing through the subject 102, the absorption coefficient of the subject 102, and the scattering probability of the subject 102. , The scattered ray distribution D (second scattered ray distribution) is obtained.

FIG. 7 is a diagram showing an example of the scattered radiation distribution D. The horizontal axis is the detection position corresponding to FIGS. 3 and 4, and the vertical axis is the scattered dose. The scattered radiation distribution D (second scattered radiation distribution) 708 is estimated by the estimation unit (second estimation unit) 508 in the projection range Q and the non-projection range R.

Next, in step S609 of FIG. 6, the correction unit 509 executes the scattered radiation distribution generation process for the entire region. The correction unit 509 corrects the scattered radiation distribution D by approximating the scattered radiation distribution D (second scattered radiation distribution) to the scattered radiation distribution C (first scattered radiation distribution), and the scattered radiation distribution of the entire region. Generate E. By applying the correction of the scattered radiation distribution D in the non-projection range R to the entire region, the scattered radiation distribution E is generated.

In this step, the scattered radiation distribution D is approximated to the scattered distribution C by multiplying the scattered radiation distribution D in the non-projection range R by a constant, and the scattered radiation distribution D in the projection range Q is similarly multiplied by a constant to obtain scattering. The line distribution D is modified to produce a scattered line distribution E. The correction unit 509 adjusts the scattered radiation distribution D (second scattered radiation distribution) in the non-projection area R so as to approximate the scattered radiation distribution C (first scattered radiation distribution) in the projection area Q and the non-projection area R. The scattered radiation distribution D is corrected by multiplying the value of the scattered radiation distribution D by a constant.

That is, the coefficient multiplied by the constant is determined by using the scattered ray distribution C in the non-projection range R. For example, the scattered ray distribution D (second scattered ray distribution) is scattered in the non-projection range R by the least square method. By approximating to the line distribution C (first scattered ray distribution), the coefficient of a constant multiple is determined.

In the present embodiment, the corrected scattered radiation distribution E is defined by the equation (1) and is obtained by the coefficient α that minimizes g in the equation (2). Here, f _E represents the scattered radiation distribution E, f _D represents the scattered radiation distribution D, f _C represents the scattered radiation distribution C, ξ represents the pixel number of the detection unit 104, and Ω represents the non-projection range R. Shows a set of pixel numbers of. Therefore, Σ in equation (2) indicates that the sum is calculated for the pixels in the non-projection range R.

In addition, the display unit 110 displays the scattered radiation distribution C (first scattered radiation distribution), the scattered radiation distribution D (second scattered radiation distribution), the scattered radiation distribution E, and a constant multiple coefficient α as necessary. indicate. This allows the operator to confirm and evaluate the processing result.

According to the present embodiment, by adjusting the scattered radiation distribution D (second scattered radiation distribution) so as to match the scattered radiation distribution C (first scattered radiation distribution), it is possible to accurately scatter the entire region. The line can be estimated.

(Third Embodiment)
Next, a third embodiment of the present invention will be described, and an embodiment in which the scattered radiation distribution estimated in the non-projection range is used to correct the scattered radiation distribution in the entire region (projection range and non-projection range) explain. Note that description of the same configurations, functions, and operations as those of the above-described embodiment will be omitted, and differences from the present embodiment will be mainly described. A third embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 8: is a figure which shows an example of a structure of the radiography system which concerns on this embodiment. FIG. 9 is a flowchart showing an example of the additional processing flow of the radiation imaging system according to this embodiment.

The present embodiment is an example in which the configuration and the processing flow are added to the configuration and the processing flow in the first embodiment. The additional configuration will be described with reference to FIG. The additional configuration is an estimation unit (second estimation unit) 808 and a correction unit 809. In the present embodiment, the estimation unit 808 and the correction unit 809 are examples of programs executed by a computer. It may be an integrated circuit as long as it has a similar function, and is not limited to the form.

Next, the operation of the configuration of FIG. 8 and the estimation of scattered radiation will be described with reference to the flowcharts of FIGS. 2 and 9.

First, in the present embodiment, as in the first embodiment, the flowchart of FIG. 2 is executed to estimate the scattered radiation distribution C in the region (non-projection range) that does not become the shadow of the subject 102.

Next, in step S908 of FIG. 9, a plurality of scattered radiation distribution estimation steps are executed by the estimation unit (second estimation unit) 808. In this step, a plurality of scattered radiation distributions of a region that is a shadow of the subject (projection range) and a region that is not a shadow of the subject (non-projection range) are estimated. Here, as in the second embodiment, the projection range is a complement of the non-projection range. Therefore, the entire area includes the projection range and the non-projection range. In this step, a plurality of scattered radiation distributions in the projected range and the non-projected range are estimated.

A known technique can be applied as a method of estimating the scattered radiation distribution D in the entire region. For example, in the case of a CT apparatus, as shown in Japanese Patent No. 5052281, using the path length of scattered rays passing through the subject 102, the absorption coefficient of the subject 102, and the scattering probability of the subject 102. , A plurality of scattered ray distributions are obtained.

In the present embodiment, the scattered ray distribution F ₁ of Compton scattering (all regions) and the scattered ray distribution F ₂ of Rayleigh scattering (all regions) are estimated using the scattering probabilities of Compton scattering and Rayleigh scattering.

FIG. 10: is a figure which shows an example of the scattered radiation distribution of the whole area by Compton scattering and Rayleigh scattering. The scattered ray distribution F ₁ by Compton scattering is shown by a scattered ray distribution 1008, and the scattered ray distribution F ₂ by Rayleigh scattering is shown by a scattered ray distribution 1009. In general, since Rayleigh scattering has a higher proportion of forward scattering, the shapes of the scattered ray distributions 1008 and 1009 of both are different as shown in FIG.

Next, in step S909 of FIG. 9, the composite scattered radiation distribution creating process is executed by the correction unit 809. In this step, the linear weighted sum (including the linear sum) of the plurality of scattered ray distributions estimated in step S908 is defined as the composite scattered ray distribution G, and the coefficient of the linear weighted sum is the scattered ray distribution in the non-projection range R. Determined using C.

The estimation unit (second estimation unit) 808 estimates a weighted sum (for example, a linear weighted sum) of a plurality of scattered ray distributions as a composite scattered ray distribution G (second scattered ray distribution).

The correction unit 809 determines the weighting coefficient of the linear weighted sum so that the composite scattered radiation distribution G (second scattered radiation distribution) approximates the scattered radiation distribution C (first scattered radiation distribution), and The scattered radiation distribution G is corrected.

For example, with respect to the non-projection range R, the weight coefficient is determined by approximating the composite scattered ray distribution G (second scattered ray distribution) to the scattered ray distribution C (first scattered ray distribution) by the least squares method.

In the present embodiment, the composite scattered radiation distribution G is defined by the equation (3) and is obtained by the weighting coefficient α _i that minimizes g in the equation (4). Here, i is a subscript added to distinguish each of the plurality of scattered radiation distributions in the entire region. Further, f _Fi represents an i-th scattered ray distribution of a plurality of scattered ray distributions in the entire region, f _G represents a composite scattered ray distribution G, f _C represents a scattered ray distribution C, and ξ represents a detection unit. A pixel number of 104 is shown, and Ω is a set of pixel numbers of the non-projection range R. Therefore, Σ in Expression (4) indicates that the sum is calculated for the pixels in the non-projection range R.

For example, in the above example, the composite scattered radiation distribution G (second scattered radiation distribution) is defined by the two scattered radiation distributions F ₁ and F ₂ as the plurality of scattered radiation distributions in the entire region. The formula (3) in this case becomes like the formula (5), and the composite scattered radiation distribution G is obtained by the weighting factors α ₁ and α ₂ that minimize g in the formula (4).

In the present embodiment, an example in which two scattered ray distributions of Compton scattering and Rayleigh scattering are used as the plurality of scattered ray distributions in the entire area has been shown, but the present embodiment is not limited to this. The scattered radiation distribution in the entire region may be a function that is uniform in space or a function that changes linearly with respect to space. In the present embodiment, the first-order (linear) weighted sum is used, but the weighted sum may be extended to the n-th order. Further, a Gaussian distribution may be used as the scattered ray distribution in the entire area. Further, a scattered radiation distribution assuming a plurality of scattering times may be estimated and used as the scattered radiation distribution in the entire region.

Further, the display unit 110 may display the scattered radiation distribution C (first scattered radiation distribution), the composite scattered radiation distribution G (second scattered radiation distribution), the scattered radiation distribution F _i , and the weighting factor α _i as necessary. Is displayed. This allows the operator to confirm and evaluate the processing result.

According to the present embodiment, the weighted sum (second scattered ray distribution) of a plurality of scattered ray distributions is adjusted so as to match the scattered ray distribution C (first scattered ray distribution), thereby achieving high accuracy. It is possible to estimate scattered rays in the entire area.

Although the specific embodiments have been described above, the present invention is not limited to these embodiments and includes various modifications and applications without departing from the scope of the claims.

The present invention supplies software (program) that realizes the functions of the above-described embodiments to a system or apparatus via a network or various storage media, and a computer (CPU, MPU, etc.) of the system or apparatus reads the program. It may be executed. The present invention can also be realized by a process in which one or more processors in a computer of a system or an apparatus read and execute a program, and can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

101 Radiation generation unit 104 Detection unit 105 First measurement unit 106 Second measurement unit 107 First estimation unit 110 Display units 508 and 808 Second estimation units 509 and 809 Correction unit

Claims (12)

First measuring means for measuring the first detection data of the radiation emitted without placing the subject ,
Second measuring means for measuring second detection data of the radiation emitted in the state where the subject is arranged;
A first estimation means for estimating a first scattered radiation distribution of the radiation in a range other than the projection range of the subject based on the first detection data and the second detection data ,
It said first estimation means, the second detection data is greater extent than the first detection data, radiographic apparatus, characterized that you defined as a range other than the projection range. First measuring means for measuring the first detection data of the radiation emitted without placing the subject,
Second measuring means for measuring second detection data of the radiation emitted in the state where the subject is arranged;
First estimating means for estimating a first scattered radiation distribution of the radiation in a range other than the projection range of the subject based on the first detection data and the second detection data.
Equipped with
It said estimating means, wherein the first detection data and the difference between the second detection data, the first scatter distribution release you and estimates ray imaging apparatus. The radiation imaging apparatus according to claim 2 , wherein the first estimating unit defines a range in which the second detection data is larger than the first detection data as a range other than the projection range. The first estimating means defines a range in which a value obtained by subtracting the first detection data from the second detection data exceeds a predetermined threshold as a range other than the projection range. The radiation imaging apparatus according to any one of 1 to 3. Second estimating means for estimating a second scattered radiation distribution of the radiation in the projection range and a range other than the projection range based on the second detection data;
5. A correction unit that corrects the second scattered radiation distribution by approximating the second scattered radiation distribution to the first scattered radiation distribution, according to any one of claims 1 to 4. The radiation imaging apparatus according to item. First measuring means for measuring the first detection data of the radiation emitted in a state where the subject is not placed,
Second measuring means for measuring second detection data of the radiation emitted in the state where the subject is arranged;
First estimating means for estimating a first scattered radiation distribution of the radiation in a range other than the projection range of the subject based on the first detection data and the second detection data,
Second estimating means for estimating a second scattered radiation distribution of the radiation in the projection range and a range other than the projection range based on the second detection data;
Correction means for correcting the second scattered radiation distribution by approximating the second scattered radiation distribution to the first scattered radiation distribution;
A radiation imaging apparatus comprising: The correction means causes the second scattered radiation in the projection range and the range other than the projection range so that the second scattered radiation distribution in the range other than the projection range approximates to the first scattered radiation distribution. by constant multiple of the value of the distribution, the radiation imaging apparatus according to claim 5 or 6, characterized in that to correct the second scattered radiation distribution. Radiation generating means for irradiating radiation,
A radiation imaging apparatus according to claim 1;
A radiation imaging system comprising: Measuring the first detection data of the radiation emitted without placing the subject ,
Measuring the second detection data of the radiation emitted in the state where the subject is arranged;
Estimating a first scattered radiation distribution of the radiation in a range other than the projection range of the subject based on the first detection data and the second detection data ,
Wherein in the step of estimating, radiographic wherein said second detection data and defining to said Rukoto greater extent than the first detection data as a range other than the projection range. Measuring the first detection data of the radiation emitted without placing the subject,
Measuring the second detection data of the radiation emitted in the state where the subject is arranged;
Estimating a first scattered radiation distribution of the radiation in a range other than the projection range of the subject based on the first detection data and the second detection data;
Equipped with
In the step of the estimating, the by the first detection data and the difference between the second detection data, radiographic wherein that you estimate the first scattered radiation distribution. Measuring the first detection data of the radiation emitted without placing the subject,
Measuring the second detection data of the radiation emitted in the state where the subject is arranged;
Estimating a first scattered radiation distribution of the radiation in a range other than the projection range of the subject based on the first detection data and the second detection data;
Estimating a second scattered radiation distribution of the radiation in the projection range and a range other than the projection range based on the second detection data;
Correcting the second scattered radiation distribution by approximating the second scattered radiation distribution to the first scattered radiation distribution,
Radiographic method comprising Rukoto equipped with. A program for causing a computer to function as each unit of the radiation imaging apparatus according to claim 1.