JP2020112530A - Radiographic imaging apparatus, radiographic imaging system, and control method of radiographic imaging apparatus - Google Patents

Abstract

To provide a method for controlling a radiographic imaging apparatus capable of detecting a dose of radiation precisely.SOLUTION: A method for controlling a radiographic imaging apparatus having a dose detection pixel for detecting a dose corresponding to radiation. The method includes a calibration step (S504) of calibrating a dose detected by the dose detection pixel on the basis of a dose of radiation applied to the radiographic imaging apparatus.SELECTED DRAWING: Figure 5

Description

The present invention relates to a radiation image pickup apparatus, a radiation image pickup system, and a control method of the radiation image pickup apparatus.

As an imaging device used for medical image diagnosis by radiation and non-destructive inspection, a radiation imaging device using a flat panel detector made of a semiconductor material is widely used. Such a radiation imaging apparatus is used, for example, in medical image diagnosis as a digital imaging apparatus for still image photographing such as general photographing and moving image photographing such as fluoroscopic photographing.

The radiation imaging device monitors the irradiation dose of radiation and terminates irradiation of radiation when the irradiation dose reaches a target value (for example, outputs a signal for stopping irradiation of radiation to the radiation source). There is something. This operation is called automatic exposure control (AEC), which can prevent, for example, excessive irradiation of radiation.

As such a radiation imaging apparatus, for example, Patent Document 1 discloses a radiation imaging apparatus in which a detector that outputs an image signal according to radiation has an irradiation dose detection pixel for detecting the irradiation dose of radiation. There is. In this radiation imaging apparatus, in order to detect the irradiation dose, a plurality of composite pixels are provided in the light collecting field in addition to the normal image signal output pixels. The composite pixel is composed of an image signal output pixel and an irradiation dose detection pixel. The radiation imaging apparatus generates a radiation detection signal indicating that the irradiation dose of the radiation has reached a predetermined value or more based on the signal from the irradiation dose detection pixel, and the radiation detection signal from the radiation source is generated based on the generated radiation detection signal. Control the timing of stopping irradiation of radiation. The lighting area of the image signal output pixel is smaller than the normal lighting area of the image signal output pixel. Therefore, the radiation imaging apparatus multiplies the output signal of the image signal output pixel by the ratio of the normal light area of the image signal output pixel to the normal light area of the image signal output pixel to obtain the image signal output pixel. Calibrate the radiation detection sensitivity.

JP, 2013-135389, A

However, in the radiation imaging apparatus, the radiation detection sensitivity may vary among the irradiation dose detection pixels due to characteristics such as photoelectric conversion efficiency of the photodiode in the irradiation dose detection pixels. In addition, in an indirect type radiation imaging device that converts radiation into visible light using a phosphor, the radiation detection sensitivity is different in the irradiation dose detection pixels between radiation imaging devices of the same model due to characteristics such as the film thickness distribution of the phosphor. It may vary. In Patent Document 1, since the radiation detection sensitivity is not calibrated for the irradiation dose detection pixels, the radiation detection sensitivity variation between the irradiation dose detection pixels and the radiation detection sensitivity variation between the radiation imaging devices cannot be calibrated.

An object of the present invention is to provide a radiation imaging apparatus, a radiation imaging system, and a radiation imaging apparatus control method capable of detecting a radiation dose with high accuracy.

A radiation image pickup apparatus of the present invention is a radiation image pickup apparatus, and based on a dose detection pixel for detecting a dose according to radiation and a dose of radiation applied to the radiation image pickup apparatus, Calibration means for calibrating the detected dose.

According to the present invention, the radiation dose can be detected with high accuracy.

It is a figure which shows the structural example of a radiation imaging system. It is a figure which shows the structural example of a radiation detection part. It is a flowchart which shows the control method of a radiation imaging system. It is a figure which shows the relationship between an output value and time. It is a flowchart which shows the control method of a radiation imaging system.

FIG. 1 is a diagram showing a configuration example of a radiation imaging system 100 according to an embodiment of the present invention. The radiation imaging system 100 will be described with respect to an example of capturing an X-ray image signal of a subject using X-rays, which is a type of radiation. Further, the radiation imaging system 100 is not limited to X-rays, and can use other radiations (for example, α-rays, β-rays, γ-rays, etc.) to capture a radiation image of a subject.

The radiation imaging system 200 is used for medical purposes, for example. The radiation imaging system 100 includes a radiation irradiation unit 101 and a radiation imaging device 107. The radiation imaging apparatus 107 includes a radiation detection unit 102, a photographing condition setting unit 103, a photographing control unit 104, an image processing unit 105, and an image display unit 106.

The radiation irradiation unit 101 irradiates the subject P with X-rays. X-rays are a type of radiation. The radiation irradiating unit 101 is a radiation generating device, and has a tube that generates X-rays, a collimator that defines the beam divergence angle of the X-rays that are generated in the tube, and an X-ray dosimeter attached to the collimator. ..

The radiation detector 102 is a flat panel detector made of a semiconductor material. The radiation detection unit 102 has a plurality of pixels arranged two-dimensionally, detects the two-dimensional distribution of the X-rays reaching the radiation detection unit 102, and generates an X-ray image signal. The radiation detection unit 102 transmits the generated X-ray image signal to the image processing unit 105, and transmits the detected X-ray dose information to the imaging control unit 104.

The imaging condition setting unit 103 has an input unit through which an operator inputs imaging conditions such as an imaging region, a target dose of X-rays irradiated on the subject P, and a tube voltage, and the imaging condition information input by the operator is imaged. It is transmitted to the control unit 104. The imaging control unit 104 controls the radiation irradiation unit 101 and the radiation detection unit 102 based on the imaging condition information received from the imaging condition setting unit 103 and the X-ray dose information received from the radiation detection unit 102.

The image processing unit 105 performs processing such as gradation processing and noise reduction processing on the X-ray image signal received from the radiation detection unit 102. The image processing unit 105 transmits the processed X-ray image signal to the image display unit 106. The image display unit 106 displays the X-ray image signal received from the image processing unit 105 on a monitor or the like.

FIG. 2 is a diagram showing a configuration example of the radiation detection unit 102 of FIG. The radiation detection unit 102 has an effective pixel area 201. The effective pixel area 201 has irradiation dose detection areas 202 to 204. The effective pixel region 201 has a plurality of image signal output pixels 205 arranged two-dimensionally. The plurality of image signal output pixels 205 detect the two-dimensional distribution information of the X-rays irradiated on the radiation imaging apparatus 107, and output the X-ray image signals according to the X-rays irradiated on the radiation imaging apparatus 107. The irradiation dose detection areas 202 to 204 have a plurality of image signal output pixels 205 and a plurality of irradiation dose detection pixels 206. The plurality of irradiation dose detection pixels 206 detect the irradiation dose according to the X-rays applied to the radiation imaging apparatus 107. The irradiation dose detection areas 202-204 have the irradiation dose detection pixels 206 of 10 rows and 30 columns, for example.

FIG. 3 is a flowchart showing a control method in the calibration mode of the radiation imaging system 100. In the calibration mode, the radiation imaging system 100 generates a calibration value for calibrating the sensitivities of the image signal output pixel 205 and the irradiation dose detection pixel 206 to the irradiation X-ray dose in the calibration mode. The radiation imaging system 100 performs the process of FIG. 3 each time immediately before the subject P is imaged.

In step S301, the photographing condition setting unit 103 transmits a sensitivity calibration start signal to the photographing control unit 104 by the operation of the operator. Upon receiving the sensitivity calibration start signal, the imaging control unit 104 sends an X-ray irradiation start signal to the radiation irradiation unit 101. Upon receiving the X-ray irradiation start signal, the radiation irradiation unit 101 uniformly irradiates the radiation detection unit 102 with X-rays. Then, the X-ray dose measuring instrument in the radiation irradiating section 101 starts X-ray dose measurement. The imaging control unit 104 transmits a sensitivity calibration imaging control signal to the radiation detection unit 102. The radiation detection unit 102 controls the pixel 205 for image signal output and the pixel 206 for irradiation dose detection based on the received sensitivity calibration imaging control signal so that they have the same accumulation time, and the pixel 205 for image signal output and the irradiation dose The detection pixels 206 convert the arrived X-rays into dose information.

In step S302, the imaging control unit 104 transmits an X-ray irradiation end signal to the radiation irradiation unit 101. Upon receiving the X-ray irradiation end signal, the radiation irradiation unit 101 stops the X-ray irradiation. Then, the X-ray dose measuring device in the radiation irradiating section 101 ends the X-ray dose measurement. Then, the imaging control unit 104 transmits an imaging control signal to the radiation detection unit 102. Upon receiving the imaging control signal, the radiation detection unit 102 controls the image signal output pixel 205 and the irradiation dose detection pixel 206 to convert the X-ray from the image signal output pixel 205 and the irradiation dose detection pixel 206 into dose information. End the conversion of. The plurality of image signal output pixels 205 generate image signals according to X-rays. The plurality of irradiation dose detection pixels 206 detect dose information according to X-rays.

In step S303, the radiation detection unit 102 transmits the dose information (pixel signal) detected by the plurality of irradiation dose detection pixels 206 in steps S301 to S302 to the imaging control unit 104.

In step S304, the radiation irradiation unit 101 transmits the X-ray dose information measured by the X-ray dose measuring device in steps S301 to S302 to the imaging control unit 104 and the image processing unit 105.

In step S305, the radiation detection unit 102 transmits the image signals (pixel signals) output by the plurality of image signal output pixels 205 in steps S301 to S302 to the image processing unit 105.

In step S306, the image processing unit 105 generates a calibration value of the sensitivity of the image signal output pixel 205 to the irradiation X-ray dose based on the X-ray dose information received in step S304 and the image signal received in step S305. The details will be described below.

In step S306, the image processing unit 105 uses Equation (1) to calculate the inter-pixel average value of the sensitivity of the image signal output pixel 205 to the irradiation X-ray dose. Here, the S image actual measurement is an inter-pixel average value of the sensitivity of the image signal output pixel 205 to the irradiation X-ray amount. Dc is the X-ray dose information measured by the X-ray dose measuring device received in step S304, and indicates the dose information of the X-rays emitted to the irradiation ray imaging device 107. i and j indicate the X coordinate and the Y coordinate of the image signal output pixel 205. Xc, i, j represent image signals (dose information) output by the plurality of image signal output pixels 205 received in step S305. Ki,j indicates the sensitivity to the irradiation X-ray dose for each image signal output pixel 205. The image processing unit 105 divides the average value of the image signals output by all the image signal output pixels 205 by the X-ray dose information measured by the X-ray dose measuring device, as shown in Expression (1), and the division is performed. The result is the inter-pixel average value of the sensitivity of the image signal output pixel 205 to the irradiation X-ray dose.

Next, the image processing unit 105 uses Expression (2) to calculate a calibration value for calibrating the X-ray detection sensitivity variation of the image signal output pixel 205 between the radiation detection units 102. The A image is a calibration value for calibrating the X-ray detection sensitivity variation of the image signal output pixel 205 between the radiation detection units 102. The S common setting is a preset X-ray detection sensitivity setting value common to the image signal output pixel 205 and the irradiation dose detection pixel 206 in the radiation detection unit 102. As shown in Expression (2), the image processing unit 105 divides the S common setting by the S image actual measurement calculated by Expression (1) to obtain the X-rays of the image signal output pixel 205 between the radiation detection units 102. A calibration value for calibrating the variation in detection sensitivity is generated.

FIG. 4A is a diagram showing the relationship between the output value of the radiation detection unit 102 before calibration and time. The output characteristic line 401 shows the output value of the radiation detection unit 102 before calibration with respect to time. The output characteristic line 402 shows the output value of another radiation detection unit 102 before calibration with respect to time. A target characteristic line (reference characteristic line) 403 shows a target output value with respect to time. The output characteristic line 401 and the output characteristic line 402 have different output values with respect to time. Further, both the output characteristic line 401 and the output characteristic line 402 are different from the target characteristic line (reference characteristic line) 403.

FIG. 4B is a diagram showing the relationship between the output value of the radiation detection unit 102 after calibration and time. The image processing unit 105 calibrates the output characteristic line 401 to the output characteristic line 404 by calculating the calibration value for calibrating the X-ray detection sensitivity variation between the radiation detection units 102, and the output characteristic line 402 to the output characteristic line 405. Can be calibrated to. In one radiation detection unit 102, the output characteristic line 401 is calibrated to the output characteristic line 404 close to the target characteristic line 403. In the other radiation detection unit 102, the output characteristic line 402 is calibrated to the output characteristic line 405 close to the target characteristic line 403. This calibration can also achieve the purpose of matching the output of the irradiation dose detection pixel 206 with the output of the image signal output pixel 205.

Next, in step S306, the image processing unit 105 uses Expression (3) to calculate a calibration value for calibrating the variation in sensitivity with respect to the irradiation X-ray dose between the image signal output pixels 205. Here, the B image i, j is a calibration value for calibrating the variation in sensitivity to the irradiation X-ray dose among the image signal output pixels 205, and is a plurality of calibration values corresponding to the plurality of image signal output pixels 205. .. The image processing unit 105 calculates the average value of the image signals Xc, i, j output by all the image signal output pixels 205 according to the equation (3) and outputs the average value of the image signals Xc output by each of the image signal output pixels 205. , I, j. As a result, the image processing unit 105 generates a calibration value that calibrates the variation in sensitivity with respect to the irradiation X-ray dose between the image signal output pixels 205. Through the above processing, the image processing unit 105 generates the A image of Expression (2) and the B image i,j of Expression (3).

Next, in step S307, the imaging control unit 104, based on the X-ray dose information received in step S304 and the dose information of the irradiation dose detection pixel 206 received in step S303, the irradiation X-ray dose of the irradiation dose detection pixel 206. Generate a calibration value for the sensitivity to. The details will be described below.

In step S307, the imaging control unit 104 calculates the inter-pixel average value of the sensitivity of the irradiation dose detection pixel 206 with respect to the irradiation X-ray dose, using Expression (4). Here, the S-dose actual measurement is an inter-pixel average value of the sensitivity of the irradiation dose detection pixel 206 to the irradiation X-ray dose. m and n indicate the X coordinate and the Y coordinate of the irradiation dose detection pixel 206. X'c,m,n indicates the dose information detected by the plurality of irradiation dose detection pixels 206 received in step S303. K′ m,n represents the sensitivity to the irradiation X-ray dose for each irradiation dose detection pixel 206. The imaging control unit 104 divides the average value of the dose information detected by all the irradiation dose detection pixels 206 by the X-ray dose information measured by the X-ray dose measuring device, as shown in Expression (4), and the division is performed. The result is the inter-pixel average value of the sensitivity of the irradiation dose detection pixel 206 to the irradiation X-ray dose.

Next, the imaging control unit 104 calculates a calibration value for calibrating the X-ray detection sensitivity variation between the radiation detection units 102 by using Expression (5). Here, the A dose is a calibration value for calibrating the X-ray detection sensitivity variation of the irradiation dose detection pixel 206 between the radiation detection units 102. As shown in Expression (5), the imaging control unit 104 divides the S common setting by the actual measurement of the S dose calculated by Expression (4), and thereby the X-ray of the irradiation dose detection pixel 206 between the radiation detection units 102. A calibration value for calibrating the variation in detection sensitivity is generated.

Next, the imaging control unit 104 calculates the calibration value for calibrating the variation in the sensitivity with respect to the irradiation X-ray dose between the irradiation dose detection pixels 206 by using Expression (6). Here, the B doses m and n are calibration values for calibrating variations in sensitivity to the irradiation X-ray dose among the irradiation dose detection pixels 206, and indicate a plurality of calibration values corresponding to the plurality of irradiation dose detection pixels 206. .. The imaging control unit 104 calculates the average value of the dose information X′c,m,n detected by all the irradiation dose detection pixels 206 by the formula (6) and the dose detected by each of the irradiation dose detection pixels 206. Divide by the information X'c,m,n. As a result, the imaging control unit 104 generates a calibration value that calibrates the variation in sensitivity with respect to the irradiation X-ray dose between the irradiation dose detection pixels 206. Through the above processing, the imaging control unit 104 generates the A dose of equation (5) and the B dose m, n of equation (6).

FIG. 5 is a flowchart showing a control method in the imaging mode of the radiation imaging system 100. In the imaging mode, the radiation imaging system 100 performs the imaging process of the subject P by the process of FIG.

In step S501, the imaging condition setting unit 103 transmits the imaging conditions of the tube voltage [kV], the tube current [mA], and the (target dose Y'p, target) to the imaging control unit 104 by the operation of the operator.

Next, in step S502, the imaging control unit 104 controls the radiation irradiation unit 101 based on the received imaging conditions. Then, the radiation irradiating unit 101 irradiates the subject P with X-rays under the imaging conditions of the tube voltage [kV] and the tube current [mA]. Then, the imaging control unit 104 transmits a subject imaging control signal to the radiation detection unit 102. The radiation detection unit 102 controls the image signal output pixel 205 and the irradiation dose detection pixel 206 based on the received imaging control signal, and the X signal reached by the image signal output pixel 205 and the irradiation dose detection pixel 206 is reached. Convert the line pixel by pixel into dose information. At that time, the irradiation dose detection pixel 206 is driven at a high frame rate with respect to the image signal output pixel 205, with a short storage time. The plurality of image signal output pixels 205 generate image signals according to X-rays. The plurality of irradiation dose detection pixels 206 detect dose information according to X-rays.

Next, in step S503, the radiation detecting unit 102 detects the dose information (pixel signals) X′p,m,n by the plurality of irradiation dose detecting pixels 206, and the dose information is detected by the plurality of irradiation dose detecting pixels 206. The dose information X′p,m,n is transmitted to the imaging control unit 104.

Next, in step S504, the imaging control unit 104 uses the formula (7) to determine the dose information X′p,m,n of the irradiation dose detection pixel 206 received in step S503 for the irradiation X dose. Calibrate the sensitivity. Here, Y'p,m,n is the dose information of each of the irradiation dose detection pixels 206 after the sensitivity calibration. D'p,m,n is the incident X-ray dose of each of the irradiation dose detection pixels 206. The imaging control unit 104 uses the formula (7) to set the dose information X′p,m,n detected by the plurality of irradiation dose detection pixels 206 to the A dose and the B dose m,n calculated in step S307. To multiply. Thereby, the imaging control unit 104 calibrates the variation in sensitivity with respect to the irradiation X-ray amount between the irradiation dose detection pixels 206 and the variation in X-ray detection sensitivity between the radiation detection units 102. The imaging control unit 104 can obtain a value obtained by multiplying the incident X-ray dose D'p,m,n by the S common setting.

Next, in step S505, the imaging control unit 104, for the dose information Y′p,m,n of all the irradiation dose detection pixels 206 calculated in step S504, dose information that exceeds a predetermined threshold value. Exclude.

Next, in step S506, the imaging control unit 104 calculates an average value (Y'p, average) of the dose information Y'p,m,n excluding the dose information excluded in step S505. Through the processing of steps S505 and S506, the imaging control unit 104 reduces the proportion of the X-ray dose that does not pass through the subject P and directly reaches the radiation detection unit 102, and then averages the dose information Y′p,m,n. Calculate the value (Y'p, average).

Next, in step S507, the imaging control unit 104 calculates, in step S506, information (Y'p, integration) of the X-ray dose that has reached the radiation detection unit 102 after passing through the subject P (Y'p, average). ) Is added to calculate a new (Y'p, integration). The initial value of (Y'p, integrated) is 0, and is the integrated value of (Y'p, average).

Next, in step S508, the imaging control unit 104 determines whether (Y'p, integration) calculated in step S507 is less than the target dose (Y'p, target) received in step S501. To do. When (Y'p, integration) is less than (Y'p, target), the imaging control unit 104 returns to step S503 and repeats the processing of steps S503 to S507. If (Y'p, integration) is (Y'p, target) or more, the imaging control unit 104 proceeds to step S509. That is, when the integrated value of the doses detected by the plurality of irradiation dose detection pixels 206 after calibration is less than the target dose, the imaging control unit 104 returns to step S503. Further, when the integrated value of the doses detected by the plurality of calibrated irradiation dose detection pixels 206 is equal to or more than the target dose, the imaging control unit 104 proceeds to step S509.

In step S<b>509, the imaging control unit 104 transmits an X-ray irradiation end signal to the radiation irradiation unit 101 and controls to end the X-ray irradiation. Upon receiving the X-ray irradiation end signal, the radiation irradiation unit 101 stops the X-ray irradiation. Then, the imaging control unit 104 transmits an imaging control signal to the radiation detection unit 102. The radiation detection unit 102 controls the image signal output pixel 205 and the irradiation dose detection pixel 206 based on the received imaging control signal, and ends the conversion from the X-ray to the dose information.

Next, in step S510, the radiation detection unit 102 transmits the image signals (pixel signals) Xp, i, j output by the plurality of image signal output pixels 205 to the image processing unit 105.

Next, in step S511, the image processing unit 105 uses the equation (8) to calculate the irradiation X-ray dose for the image signals Xp,i,j of the plurality of image signal output pixels 205 received in step S510. Calibrate the sensitivity. Here, Yp,i,j are the image signals of the plurality of image signal output pixels 205 after the sensitivity calibration. Dp,i,j is the incident X-ray dose of each of the plurality of image signal output pixels 205. The image processing unit 105 multiplies the image signals Xp,i,j output by the plurality of image signal output pixels 205 by the formula (8) and the A image and B image i,j calculated in step S306. , Yp,i,j. As a result, the image processing unit 105 calibrates the variation in sensitivity with respect to the irradiation X-ray dose between the image signal output pixels 205 and the variation in X-ray detection sensitivity between the radiation detection units 102. The image processing unit 105 can obtain a value Yp,i,j by multiplying the incident X-ray dose Dp,i,j by the S common setting.

In step S512, the image processing unit 105 performs gradation processing and noise reduction processing on the image signals Yp, i, j of the plurality of image signal output pixels 205 after the sensitivity calibration calculated in step S511. Next, the image processing unit 105 transmits the processed image signal to the image display unit 106.

Next, in step S513, the image display unit 106 converts the image signal received from the image processing unit 105 into a two-dimensional image and displays the two-dimensional image. With the above, the subject photographing process is completed.

As described above, in step S307, the imaging control unit 104 is the calibration unit, and the radiation image pickup device 107 is irradiated with the dose information X′c,m,n detected by the plurality of irradiation dose detection pixels 206. Based on the X-ray dose information Dc, the A dose and the B dose m, n are generated. The A dose is a calibration value shown in equation (5). The B doses m and n are a plurality of calibration values corresponding to a plurality of irradiation dose detection pixels 206, as shown in Expression (6).

In step S504, the imaging control unit 104 uses the A-dose and the B-dose m,n as shown in Expression (7), and the dose information X′p,m detected by the plurality of irradiation dose detection pixels 206. , N are calibrated.

Further, in step S306, the image processing unit 105 is a calibration unit, and the image signals Xc, i, j output by the plurality of image signal output pixels 205 and the dose of X-rays irradiated to the radiation imaging apparatus 107. An A image and a B image i,j are generated based on the information Dc. The A image is the calibration value shown in equation (2). The B images i and j are a plurality of calibration values corresponding to a plurality of image signal output pixels 205, as shown in Expression (3).

In step S511, the image processing unit 105 uses the A image and the B image i,j to output the image signal Xp,i,j output by the plurality of image signal output pixels 205 as shown in Expression (8). Calibrate.

The radiation imaging system 100 may perform the process of FIG. 3 in a process of manufacturing the radiation imaging system 100. Moreover, the radiation imaging system 100 may perform the process of FIG. 3 when installing the radiation imaging system 100 in a use place. Moreover, the radiation imaging system 100 may perform the process of FIG. 3 periodically, such as every month.

Moreover, the radiation imaging system 100 may measure the X-ray dose irradiated from the radiation irradiation unit 101 by the X-ray dose measuring device in advance, and use the measured dose to perform the process of FIG. 3. That is, the radiation imaging system 100 measures the X-ray dose irradiated from the radiation irradiation unit 101 by the X-ray dose measuring device in advance, and irradiates the X-ray under the same irradiation condition as the X-ray dose measurement in step S301. Then, the radiation imaging system 100 processes the X-ray dose information measured in advance in steps S306 and S307 as Dc.

In the case where the radiation imaging system 100 calculates the B doses m and n for calibrating the variation in sensitivity with respect to the irradiation X-ray dose between the irradiation dose detection pixels 206 in 10 rows and 30 columns, and calibrating the variation in sensitivity for each pixel. Explained. In the radiation imaging system 100, the radiation detection unit 102 or the imaging control unit 104 may be provided with a binning circuit that adds or averages signals output from the irradiation dose detection pixels 206 in a plurality of rows or a plurality of columns. Then, the radiation imaging system 100 may perform the process of FIG. 3 and the process of FIG. 5 on the signal output from the irradiation dose detection pixel 206 after addition or averaging of a plurality of columns. Further, the binning circuit averages all signals output from the irradiation dose detection pixels 206 in 5 rows and 10 columns in each of the irradiation dose detection areas 202 to 204 shown in FIG. You may perform a process and the process of FIG.

That is, in the calibration mode of FIG. 3, the imaging control unit 104 performs addition or averaging on the dose detected by the plurality of irradiation dose detection pixels 206 for each of two or more irradiation dose detection pixels 206, A calibration value is generated based on the dose after addition or averaging. Further, in the imaging mode of FIG. 5, the imaging control unit 104 performs addition or averaging on the dose detected by the plurality of irradiation dose detection pixels 206 for each of two or more irradiation dose detection pixels 206, The above calibration values are used to calibrate the dose after addition or averaging.

Further, in the calibration mode of FIG. 3, the image processing unit 105 performs addition or averaging on the image signals output by the plurality of image signal output pixels 205 for every two or more image signal output pixels 205. , A calibration value is generated based on the image signal after addition or averaging. Further, in the shooting mode of FIG. 5, the image processing unit 105 performs addition or averaging on the image signals output by the plurality of image signal output pixels 205 for every two or more image signal output pixels 205. , The image signal after addition or averaging is calibrated using the above calibration value.

As described above, in the radiation imaging system 100, the variation in the X-ray detection sensitivity of the irradiation dose detection pixels 206 between the radiation detection units 102 and the variation in the sensitivity of the irradiation dose detection pixels 206 with respect to the irradiation X-ray dose can be performed with high accuracy. Can be calibrated. Accordingly, the radiation imaging system 100 can control the X-ray irradiation dose with high accuracy.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. It can also be realized by the processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

It should be noted that each of the above-described embodiments is merely an example of an embodiment for carrying out the present invention, and the technical scope of the present invention should not be limitedly interpreted by these. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

100: Radiation imaging system, 101: Radiation irradiation unit, 102: Radiation detection unit, 103: Imaging condition setting unit, 104: Imaging control unit, 105: Image processing unit, 106: Image display unit, 107: Radiation imaging device, 205 : Pixel for outputting image signal, 206: pixel for detecting irradiation dose

Claims (20)

A radiation imaging apparatus,
A dose detection pixel for detecting a dose according to radiation,
A radiation image pickup apparatus comprising: a calibration unit that calibrates a dose detected by the dose detection pixel based on a dose of radiation applied to the radiation image pickup apparatus. The calibration means,
In the calibration mode, a first calibration value is generated based on the dose detected by the dose detection pixel and the dose of radiation applied to the radiation imaging apparatus,
The radiation imaging apparatus according to claim 1, wherein in the imaging mode, the dose detected by the dose detection pixel is calibrated using the first calibration value. The radiation imaging apparatus has a plurality of dose detection pixels for detecting a dose according to radiation,
The calibration means,
In the calibration mode, a result obtained by dividing the average value of the doses detected by the plurality of dose detection pixels by the dose of the radiation applied to the radiation imaging apparatus is a first division result, and the sensitivity setting value is the first set value. Divide by the division result of to generate the first calibration value,
The radiation imaging apparatus according to claim 1, wherein in the imaging mode, the dose detected by the plurality of dose detection pixels is calibrated using the first calibration value. The radiation imaging apparatus has a plurality of dose detection pixels for detecting a dose according to radiation,
The calibration means,
In the calibration mode, based on the dose detected by the plurality of dose detecting pixels and the dose of the radiation applied to the radiation imaging apparatus, a plurality of first calibrations corresponding to the plurality of dose detecting pixels are performed. Produces a value,
The radiation imaging apparatus according to claim 1, wherein in the imaging mode, the doses detected by the plurality of dose detection pixels are calibrated using the plurality of first calibration values. The radiation imaging apparatus has a plurality of dose detection pixels for detecting a dose according to radiation,
The calibration means,
In the calibration mode, an average value of doses detected by the plurality of dose detection pixels is divided by a dose detected by the plurality of dose detection pixels, and a plurality of first doses corresponding to the plurality of dose detection pixels are obtained. Generates a calibration value of
The radiation imaging apparatus according to claim 1, wherein in the imaging mode, the doses detected by the plurality of dose detection pixels are calibrated using the plurality of first calibration values. The calibration means,
In the calibration mode, the result obtained by dividing the average value of the doses detected by the plurality of dose detection pixels by the dose of the radiation applied to the radiation imaging apparatus is a first division result, and the sensitivity setting value is the first set value. Divide by the division result of 1 to generate the second calibration value,
The dose detected by the plurality of dose detection pixels is calibrated in the imaging mode by using the plurality of first calibration values and the second calibration value. Radiation imaging device. The calibration means,
In the calibration mode, the dose detected by the plurality of dose detecting pixels is added or averaged for every two or more dose detecting pixels, and a dose is added based on the dose after the addition or averaging. Generate a calibration value of 1,
In the imaging mode, the dose detected by the plurality of dose detecting pixels is added or averaged for every two or more dose detecting pixels, and the addition or averaging is performed using the first calibration value. The radiation imaging apparatus according to claim 3, wherein the dose after averaging is calibrated. When the integrated value of the dose detected by the dose detecting pixel calibrated by the calibrating unit becomes equal to or more than the target dose, the control unit further includes a control unit for controlling the irradiation of radiation to be terminated. The radiation imaging apparatus according to claim 1. The radiation image pickup apparatus according to claim 1, further comprising a plurality of image signal output pixels that output an image signal according to radiation. 10. The radiation imaging apparatus according to claim 9, wherein the calibration unit calibrates the image signals output by the plurality of image signal output pixels based on the dose of radiation applied to the radiation imaging apparatus. apparatus. The calibration means,
In the calibration mode, a third calibration value is generated based on the image signals output by the plurality of image signal output pixels and the dose of radiation applied to the radiation imaging apparatus,
The radiation imaging apparatus according to claim 9, wherein in the imaging mode, the third calibration value is used to calibrate the image signal output by the plurality of image signal output pixels. The calibration means,
In the calibration mode, the result of dividing the average value of the image signals output by the plurality of image signal output pixels by the dose of the radiation applied to the radiation imaging apparatus is the second division result, and the sensitivity setting value is the Divide by the second division result to generate the third calibration value,
The radiation imaging apparatus according to claim 9, wherein in the imaging mode, the third calibration value is used to calibrate the image signal output by the plurality of image signal output pixels. The calibration means,
In the calibration mode, based on the image signals output by the plurality of image signal output pixels and the dose of radiation applied to the radiation imaging apparatus, a plurality of first image signal output pixels corresponding to the plurality of image signal output pixels. Generate a calibration value of 3,
The radiation imaging apparatus according to claim 9, wherein in the imaging mode, the image signals output by the plurality of image signal output pixels are calibrated using the plurality of third calibration values. The calibration means,
In the calibration mode, the average value of the image signals output by the plurality of image signal output pixels is divided by the image signal output by the plurality of image signal output pixels to correspond to the plurality of image signal output pixels. Generate a plurality of third calibration values that
The radiation imaging apparatus according to claim 9, wherein in the imaging mode, the image signals output by the plurality of image signal output pixels are calibrated using the plurality of third calibration values. The calibration means,
In the calibration mode, the result of dividing the average value of the image signals output by the plurality of image signal output pixels by the dose of the radiation applied to the radiation imaging apparatus is the second division result, and the sensitivity setting value is Divide by the second division result to generate a fourth calibration value,
The image signal output from the plurality of image signal output pixels is calibrated in the photographing mode by using the plurality of third calibration values and the fourth calibration value. The radiation imaging apparatus described. The calibration means,
In the calibration mode, the image signals output by the plurality of image signal output pixels are added or averaged for every two or more image signal output pixels, and the image signal after the addition or averaging is performed. Generate a third calibration value based on
In the shooting mode, the image signals output by the plurality of image signal output pixels are added or averaged for every two or more image signal output pixels, and the third calibration value is used. The radiation image pickup apparatus according to claim 11, wherein the image signal after the addition or the averaging is calibrated. 17. The display device according to claim 10, further comprising a display unit that displays an image based on the image signals output by the plurality of image signal output pixels that have been calibrated by the calibration unit. Radiation imaging device. 18. The radiation according to claim 1, wherein the radiation dose applied to the radiation imaging device is a dose measured by a dose measuring unit of a radiation generation device that emits the radiation. Imaging device. A radiation imaging apparatus according to any one of claims 1 to 18,
A radiation imaging system, comprising: a radiation generation device that irradiates the radiation imaging device with radiation. A method for controlling a radiation imaging apparatus having a dose detecting pixel for detecting a dose according to radiation, comprising:
A method of controlling a radiation imaging apparatus, comprising: a calibration step of calibrating a dose detected by the dose detecting pixel based on a dose of radiation applied to the radiation imaging apparatus.

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