JP7246936B2 - Radiation imaging apparatus, radiation imaging system, and radiation imaging apparatus control method - Google Patents

Description

The present invention relates to a radiation imaging apparatus, a radiation imaging system, and a control method for the radiation imaging apparatus.

2. Description of the Related Art A radiation imaging apparatus using a flat panel detector made of a semiconductor material is widely used as an imaging apparatus used for medical image diagnosis and non-destructive inspection using radiation. Such radiation imaging apparatuses are used, for example, in medical image diagnosis as digital imaging apparatuses for still image capturing such as general radiography and moving image capturing such as fluoroscopic imaging.

The radiation imaging apparatus monitors the irradiation dose of radiation and terminates the irradiation of radiation when the irradiation dose reaches a target value (for example, outputs a signal to the radiation source to stop the irradiation of radiation). ) there is something. This operation is referred to as Automatic Exposure Control (AEC) and can prevent, for example, overexposure 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 corresponding to radiation has irradiation dose detection pixels for detecting the irradiation dose of radiation. there is In order to detect the irradiation dose, this radiation imaging apparatus has a plurality of composite pixels in addition to normal image signal output pixels within the lighting field. A composite pixel is composed of an image signal output pixel and a radiation dose detection pixel. The radiation imaging apparatus generates a radiation detection signal indicating that the radiation dose has reached or exceeded a predetermined value based on the signal from the radiation dose detection pixels, and detects radiation from the radiation source based on the generated radiation detection signal. Controls the timing of stopping radiation irradiation. The light-receiving area of the image signal output pixel is smaller than the light-receiving area of the normal image signal output pixel. Therefore, the radiation imaging apparatus multiplies the output signal of the image signal output pixel by the normal ratio of the light receiving area of the image signal output pixel to the light receiving area of 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 radiation dose detection pixels due to the characteristics such as the photoelectric conversion efficiency of the photodiodes in the radiation dose detection pixels. In addition, in an indirect type radiation imaging apparatus that converts radiation into visible light using a phosphor, the radiation detection sensitivity of the pixels for detecting the radiation dose between radiation imaging apparatuses of the same model varies depending on characteristics such as the film thickness distribution of the phosphor. It may fluctuate. In Patent Document 1, radiation detection sensitivity is not calibrated for the radiation dose detection pixels, and thus variations in radiation detection sensitivity between radiation dose detection pixels and radiation detection sensitivity variations between radiation imaging apparatuses cannot be calibrated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiation imaging apparatus, a radiation imaging system, and a control method of the radiation imaging apparatus that can detect radiation dose with high accuracy.

A radiation imaging apparatus according to the present invention is a radiation imaging apparatus comprising: a panel including a plurality of dose detection pixels for outputting pixel values according to radiation dose; Holds first calibration information for calibrating the output to a target output common to other devices , and second calibration information for calibrating variation in the output of each of the plurality of dose detection pixels. holding means; communication means for performing communication processing for stopping radiation irradiation by the radiation generating device; a plurality of pixel values corresponding to at least the plurality of dose detection pixels; the first calibration information; determining means for determining execution timing of the communication process based on the calibration information of the communication processing;

According to the present invention, the dose of radiation 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. 4 is a flow chart showing a control method of the radiation imaging system; It is a figure which shows the relationship between an output value and time. 4 is a flow chart showing a control method of the 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. An example in which the radiation imaging system 100 captures an X-ray image signal of a subject using X-rays, which is a type of radiation, will be described. Moreover, the radiation imaging system 100 can capture a radiographic image of a subject using, for example, other radiation (eg, α-rays, β-rays, γ-rays, etc.) in addition to X-rays.

The radiation imaging system 200 is used for medical purposes, for example. The radiation imaging system 100 has a radiation irradiation unit 101 and a radiation imaging device 107 . The radiation imaging apparatus 107 has a radiation detection unit 102 , an imaging condition setting unit 103 , an imaging 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 irradiation unit 101 is a radiation generator, and includes a tube that generates X-rays, a collimator that defines the beam divergence angle of the X-rays generated in the tube, and an X-ray dosimeter attached to the collimator. .

The radiation detection unit 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 a two-dimensional distribution of 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 detected X-ray dose information to the imaging control unit 104 .

The imaging condition setting unit 103 has input means for the operator to input imaging conditions such as the imaging site, the target dose of X-rays applied to the subject P, tube voltage, etc., and the imaging condition information input by the operator is used for imaging. 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 in FIG. The radiation detection unit 102 has an effective pixel area 201 . The effective pixel area 201 has irradiation dose detection areas 202-204. The effective pixel area 201 has a plurality of image signal output pixels 205 arranged two-dimensionally. The plurality of image signal output pixels 205 detect two-dimensional distribution information of X-rays irradiated to the radiation imaging device 107 and output X-ray image signals corresponding to the X-rays irradiated to the radiation imaging device 107 . The radiation dose detection areas 202 to 204 have a plurality of image signal output pixels 205 and a plurality of radiation dose detection pixels 206 . A plurality of irradiation dose detection pixels 206 detect the irradiation dose according to the X-rays irradiated to the radiation imaging apparatus 107 . The radiation dose detection areas 202 to 204 have, for example, radiation dose detection pixels 206 arranged in 10 rows and 30 columns.

FIG. 3 is a flow chart showing a control method in the calibration mode of the radiation imaging system 100. As shown in FIG. In the calibration mode, the radiation imaging system 100 generates calibration values for calibrating the sensitivities of the image signal output pixels 205 and the radiation dose detection pixels 206 with respect to the dose of irradiation X-rays through the processing of FIG. The radiation imaging system 100 performs the processing in FIG. 3 every time immediately before the subject P is imaged.

In step S301, the imaging condition setting unit 103 transmits a sensitivity calibration start signal to the imaging control unit 104 by the operator's operation. Upon receiving the sensitivity calibration start signal, the imaging control unit 104 transmits 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 dosimeter in the radiation irradiation unit 101 starts X-ray dosimetry. The imaging control unit 104 transmits a sensitivity calibration imaging control signal to the radiation detection unit 102 . Based on the received sensitivity calibration imaging control signal, the radiation detection unit 102 controls the image signal output pixels 205 and the irradiation dose detection pixels 206 to have the same accumulation time. The detection pixels 206 convert the arriving X-rays into dose information.

In step S<b>302 , 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 X-ray irradiation. Then, the X-ray dosimeter in the radiation irradiation unit 101 ends the X-ray dosimetry. The imaging control unit 104 then 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 pixels 205 and the radiation dose detection pixels 206, and converts the image signal output pixels 205 and the radiation dose detection pixels 206 from X-rays to dose information. end the conversion of The plurality of image signal output pixels 205 generate image signals corresponding to X-rays. A plurality of irradiation dose detection pixels 206 detect dose information according to X-rays.

In step S 303 , the radiation detection unit 102 transmits dose information (pixel signals) detected by the plurality of irradiation dose detection pixels 206 in steps S 301 and S 302 to the imaging control unit 104 .

In step S 304 , the radiation irradiation unit 101 transmits the X-ray dose information measured by the X-ray dosimeter in steps S 301 and S 302 to the imaging control unit 104 and the image processing unit 105 .

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

In step S306, the image processing unit 105 generates a calibration value of the sensitivity of the image signal output pixels 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 are described below.

In step S<b>306 , the image processing unit 105 calculates an inter-pixel average value of the sensitivity of the image signal output pixels 205 to the irradiation X-ray dose using Equation (1). Here, the S image actual measurement is an inter-pixel average value of the sensitivity of the image signal output pixels 205 to the irradiation X-ray dose. Dc is the X-ray dose information measured by the X-ray dosimeter received in step S304 and indicates the dose information of the X-ray irradiated to the radiation imaging device 107 . i and j represent the X and Y coordinates 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 represents the sensitivity of each image signal output pixel 205 to the irradiation X-ray dose. The image processing unit 105 divides the average value of the image signals output from all the image signal output pixels 205 by the X-ray dose information measured by the X-ray dosimeter as shown in Equation (1), The result is taken as an inter-pixel average value of the sensitivities of the image signal output pixels 205 to the irradiation X-ray dose.

Next, the image processing unit 105 calculates a calibration value for calibrating variations in X-ray detection sensitivity of the image signal output pixels 205 between the radiation detection units 102 using Equation (2). The A image is a calibration value for calibrating variations in X-ray detection sensitivity of the image signal output pixels 205 among the radiation detection units 102 . The S common setting is a preset common X-ray detection sensitivity setting value for the image signal output pixels 205 and the radiation dose detection pixels 206 in the radiation detection unit 102 . As shown in Equation (2), the image processing unit 105 divides the S common setting by the S image measurement calculated by Equation (1), thereby obtaining X-rays from the image signal output pixels 205 between the radiation detection units 102 A calibration value is generated to calibrate the detection sensitivity variation.

FIG. 4A is a diagram showing the relationship between the output value of the radiation detection unit 102 before calibration and time. An output characteristic line 401 indicates the output value of one radiation detection unit 102 before calibration with respect to time. An output characteristic line 402 indicates the output value of the other radiation detection unit 102 before calibration with respect to time. A target characteristic line (reference characteristic line) 403 indicates 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. 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 and converts the output characteristic line 402 to the output characteristic line 405 by calculating calibration values for calibrating X-ray detection sensitivity variations among the radiation detection units 102 . can be calibrated to In one radiation detection unit 102 , the output characteristic line 401 is calibrated to an output characteristic line 404 close to the target characteristic line 403 . In other radiation detection units 102 , the output characteristic line 402 is calibrated to an output characteristic line 405 close to the target characteristic line 403 . This calibration also achieves the purpose of matching the output of the radiation dose detection pixels 206 with the output of the image signal output pixels 205 .

Next, in step S<b>306 , the image processing unit 105 calculates a calibration value for calibrating variations in sensitivity with respect to the irradiation X-ray dose among the image signal output pixels 205 using Equation (3). Here, the B images i and j are calibration values for calibrating variations in sensitivity with respect to the irradiation X-ray dose between the image signal output pixels 205, and are a plurality of calibration values corresponding to the plurality of image signal output pixels 205. . The image processing unit 105 converts the average value of the image signals Xc, i, and j output by all the image signal output pixels 205 to the image signal Xc output by each of the image signal output pixels 205 by Equation (3). , i, j. Thereby, the image processing unit 105 generates a calibration value for calibrating variations in sensitivity 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 images i and j of expression (3).

Next, in step S307, the imaging control unit 104 calculates the irradiation X-ray dose of the irradiation dose detection pixels 206 based on the X-ray dose information received in step S304 and the dose information of the irradiation dose detection pixels 206 received in step S303. Generates a sensitivity calibration value for The details are described below.

In step S<b>307 , the imaging control unit 104 calculates an inter-pixel average value of the sensitivity of the irradiation dose detection pixels 206 to the X-ray dose using Equation (4). Here, the measured S dose is the inter-pixel average value of the sensitivity of the irradiation dose detection pixels 206 to the irradiation X-ray dose. m and n indicate the X-coordinate and Y-coordinate of the irradiation dose detection pixel 206 . X'c,m,n represent the dose information detected by the plurality of irradiation dose detection pixels 206 received in step S303. K′ m,n represents the sensitivity of each irradiation dose detection pixel 206 to the irradiation X-ray dose. As shown in equation (4), 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 dosimeter, The result is used as an inter-pixel average value of the sensitivity of the irradiation dose detection pixels 206 to the irradiation X-ray dose.

Next, the imaging control unit 104 calculates a calibration value for calibrating variations in X-ray detection sensitivity among the radiation detection units 102 using Equation (5). Here, the A dose is a calibration value for calibrating variations in X-ray detection sensitivity of the radiation dose detection pixels 206 among the radiation detection units 102 . As shown in Equation (5), the imaging control unit 104 divides the S common setting by the measured S dose calculated by Equation (4), thereby obtaining the X-ray dose detection pixels 206 between the radiation detection units 102 A calibration value is generated to calibrate the detection sensitivity variation.

Next, the imaging control unit 104 uses Equation (6) to calculate a calibration value for calibrating variations in sensitivity to the X-ray dose between the dose detection pixels 206 . Here, the B doses m and n are calibration values for calibrating variations in sensitivity with respect to the irradiation X-ray dose between 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, and n detected by all the irradiation dose detection pixels 206 according to the equation (6) as the dose detected by each of the irradiation dose detection pixels 206. Divide by the information X'c,m,n. Thereby, the imaging control unit 104 generates a calibration value for calibrating variations in sensitivity 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 formula (5) and the B doses m and n of formula (6).

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

In step S<b>501 , the imaging condition setting unit 103 transmits imaging conditions such as tube voltage [kV], tube current [mA], and (target dose Y′p, target) to the imaging control unit 104 by the operator's operation.

Next, in step S502, the imaging control unit 104 controls the radiation irradiation unit 101 based on the received imaging conditions. Then, the radiation irradiation unit 101 irradiates the subject P with X-rays under the imaging conditions of tube voltage [kV] and tube current [mA]. The imaging control unit 104 then transmits a subject imaging control signal to the radiation detection unit 102 . The radiation detection unit 102 controls the image signal output pixels 205 and the radiation dose detection pixels 206 based on the received imaging control signal, and the image signal output pixels 205 and the radiation dose detection pixels 206 detect the X Transform lines into dose information pixel by pixel. At this time, the irradiation dose detection pixels 206 are driven with a shorter accumulation time and at a higher frame rate than the image signal output pixels 205 . The plurality of image signal output pixels 205 generate image signals corresponding to X-rays. A plurality of irradiation dose detection pixels 206 detect dose information according to X-rays.

Next, in step S<b>503 , the radiation detection unit 102 detects dose information (pixel signals) X′ p, m, n using the plurality of irradiation dose detection pixels 206 , and The obtained dose information X′p, m, n is transmitted to the imaging control unit 104 .

Next, in step S504, the imaging control unit 104 uses equation (7) to convert the dose information X′p,m,n of the irradiation dose detection pixels 206 received in step S503 into Calibrate the sensitivity. Here, Y'p, m, and n are dose information of each of the irradiation dose detection pixels 206 after sensitivity calibration. D'p, m, and n are incident X-ray doses of each of the irradiation dose detection pixels 206; The imaging control unit 104 adds the A dose and the B dose m, n calculated in step S307 to the dose information X′p, m, n detected by the plurality of irradiation dose detection pixels 206 according to Equation (7). Multiply. Thereby, the imaging control unit 104 calibrates the variation in sensitivity to the X-ray dose between the radiation 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 controls the dose information Y'p,m,n of all the irradiation dose detection pixels 206 calculated in step S504 to dose information exceeding a predetermined threshold value. to exclude.

Next, in step S506, the imaging control unit 104 calculates the average value (Y'p, average) of the dose information Y'p,m,n excluding the dose information excluded in step S505. Through the processing in steps S505 and S506, the imaging control unit 104 reduces the proportion of the X-ray dose that reaches the radiation detection unit 102 directly without penetrating the subject P, and then averages the dose information Y′p, m, n. Calculate the value (Y'p, mean).

Next, in step S507, the imaging control unit 104 adds (Y'p, average ) and compute a new (Y'p, sum). (Y'p, integrated) has an initial value of 0 and is the integrated value of (Y'p, average).

Next, in step S508, the imaging control unit 104 determines whether (Y'p, integrated) calculated in step S507 is less than the target dose (Y'p, target) received in step S501. do. If (Y'p, integrated) 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, integrated) is equal to or greater than (Y'p, target), the imaging control unit 104 proceeds to step S509. That is, if the integrated value of doses detected by the plurality of exposure dose detection pixels 206 after calibration is less than the target dose, the imaging control unit 104 returns to step S503. If the integrated value of doses detected by the plurality of exposure dose detection pixels 206 after calibration is equal to or greater 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 X-ray irradiation. Upon receiving the X-ray irradiation end signal, the radiation irradiation unit 101 stops X-ray irradiation. The imaging control unit 104 then transmits an imaging control signal to the radiation detection unit 102 . The radiation detection unit 102 controls the image signal output pixels 205 and the irradiation dose detection pixels 206 based on the received imaging control signal, and ends conversion from X-rays to dose information.

Next, in step S<b>510 , 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 equation (8) to convert the image signals Xp,i,j of the plurality of image signal output pixels 205 received in step S510 into Calibrate the sensitivity. Here, Yp,i,j are image signals of each of the plurality of image signal output pixels 205 after sensitivity calibration. Dp,i,j are incident X-ray doses of each of the plurality of image signal output pixels 205 . The image processing unit 105 multiplies the image signals Xp,i,j output from the plurality of image signal output pixels 205 by the A image and the B image i,j calculated in step S306 according to equation (8). , Yp,i,j. Thereby, the image processing unit 105 calibrates the variation in sensitivity 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 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 processing of photographing the subject is completed.

As described above, in step S<b>307 , the imaging control unit 104 is a calibration unit, and the dose information X′c,m,n detected by the plurality of irradiation dose detection pixels 206 is Based on the obtained X-ray dose information Dc, A doses and B doses m and n are generated. The A dose is the calibrated value shown in Equation (5). The B doses m and n are a plurality of calibration values corresponding to the plurality of irradiation dose detection pixels 206, as shown in Equation (6).

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

In step S<b>306 , 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 are calculated. An A image and B images i and 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 Equation (3).

In step S511, the image processing unit 105 calculates the image signals Xp,i,j output from the plurality of image signal output pixels 205 using the A image and the B image i,j as shown in Equation (8). to calibrate.

Note that the radiation imaging system 100 may perform the processing of FIG. 3 in the process of manufacturing the radiation imaging system 100 . Moreover, the radiation imaging system 100 may perform the processing of FIG. 3 when the radiation imaging system 100 is installed at the place of use. Moreover, the radiation imaging system 100 may perform the processing of FIG. 3 periodically, such as once a month.

Alternatively, the radiation imaging system 100 may measure the dose of X-rays emitted from the radiation irradiation unit 101 by an X-ray dosimeter in advance, and perform the processing in FIG. 3 using the measured dose. That is, the radiation imaging system 100 measures in advance the dose of X-rays emitted from the radiation irradiation unit 101 by the X-ray dosimeter, and in step S301 irradiates X-rays under the same irradiation conditions as when measuring the X-ray dose. Then, the radiation imaging system 100 processes the X-ray dose information measured in advance in steps S306 and S307 as Dc.

In addition, when the radiation imaging system 100 calculates the B doses m and n for calibrating the sensitivity variation with respect to the irradiation X-ray dose between the irradiation dose detection pixels 206 of 10 rows and 30 columns, and corrects the sensitivity variation 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 the signals output from the radiation dose detection pixels 206 in multiple rows or multiple columns. Then, the radiation imaging system 100 may perform the processing in FIG. 3 and the processing in FIG. 5 on the signals output from the irradiation dose detection pixels 206 after multi-column addition or averaging. The binning circuit averages all signals output from the radiation dose detection pixels 206 arranged in 5 rows and 10 columns in each of the radiation dose detection regions 202 to 204 shown in FIG. process and the process of FIG. 5 may be performed.

That is, in the calibration mode of FIG. 3, the imaging control unit 104 adds or averages the doses detected by the plurality of irradiation dose detection pixels 206 for each of the two or more irradiation dose detection pixels 206, A calibration value is generated based on the dose after summation or averaging. In addition, in the imaging mode of FIG. 5, the imaging control unit 104 adds or averages the doses detected by the plurality of irradiation dose detection pixels 206 for each of the 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 adds or averages the image signals output from the plurality of image signal output pixels 205 for each of two or more image signal output pixels 205. , to generate a calibration value based on the image signal after addition or averaging. 5, the image processing unit 105 adds or averages the image signals output by the plurality of image signal output pixels 205 for every two or more image signal output pixels 205. , using the above calibration values to calibrate the image signal after addition or averaging.

As described above, the radiation imaging system 100 can accurately detect variations in the X-ray detection sensitivity of the radiation dose detection pixels 206 among the radiation detection units 102 and variations in sensitivity to the irradiation X-ray dose among the radiation dose detection pixels 206. can be calibrated. Thereby, 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 the computer of the system or apparatus reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

It should be noted that the above-described embodiments are merely examples of specific implementations of the present invention, and the technical scope of the present invention should not be construed to be limited by these. That is, the present invention can be embodied in various forms without departing from its technical concept or main features.

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 apparatus, 205 : image signal output pixels, 206: exposure dose detection pixels

Claims (23)

A radiation imaging device,
A panel comprising a plurality of dose detection pixels for outputting a pixel value according to the dose of radiation;
first calibration information for calibrating the output of the plurality of dose detection pixels as a whole to a target output common to other devices ; and for calibrating variations in the output of each of the plurality of dose detection pixels a holding means for holding the second calibration information of
communication means for performing communication processing for stopping irradiation of radiation by the radiation generating device;
determination means for determining execution timing of the communication process based on at least a plurality of pixel values corresponding to the plurality of dose detection pixels, the first calibration information, and the second calibration information;
A radiation imaging apparatus characterized by comprising: The first calibration information and the second calibration information are
A plurality of pixel values corresponding to the plurality of dose detection pixels, generated based on a first plurality of pixel values obtained in a calibration mode ,
2. The radiation imaging apparatus according to claim 1, wherein the second plurality of pixel values, which are the plurality of pixel values corresponding to the plurality of dose detection pixels and which are obtained in the imaging mode, are used for calibration . 2. The radiation imaging apparatus according to claim 1, wherein an output of the plurality of dose detection pixels as a whole is an average value or an added value of pixel values of the plurality of dose detection pixels. The communication process is executed in accordance with the fact that the integrated value of the values obtained by calibrating the plurality of pixel values corresponding to the plurality of dose detection pixels with the first calibration information and the second calibration information becomes equal to or greater than a target value. 4. The radiation imaging apparatus according to any one of claims 1 to 3, wherein: 3. The radiographic imaging apparatus according to claim 2, wherein said panel further has a plurality of image signal output pixels for outputting radiographic images. Third calibration information for calibrating the output of the plurality of image signal output pixels as a whole to a target output common to other devices, and calibrating variations in the output of each of the plurality of image signal output pixels holding means for holding fourth calibration information for
means for outputting a radiographic image based on at least a plurality of pixel values corresponding to the plurality of image signal output pixels, the third calibration information, and the fourth calibration information;
6. The radiation imaging apparatus according to claim 5, comprising: The third calibration information and the fourth calibration information are
Generated based on a third plurality of pixel values, which are the plurality of pixel values corresponding to the plurality of image signal output pixels and obtained in the calibration mode,
7. The radiation imaging apparatus according to claim 6, wherein the fourth plurality of pixel values, which are the plurality of pixel values corresponding to the plurality of image signal output pixels and which are obtained in the imaging mode, are used for calibration. The radiation according to any one of claims 5 to 7, wherein the output of the plurality of image signal output pixels as a whole is an average value or an added value of the plurality of image signal output pixels. Imaging device. comprising means for acquiring dose information of the radiation emitted by the radiation generating device from the radiation generating device;
3. The radiation according to claim 2, wherein the average value of the sensitivities of the plurality of dose detection pixels is a value obtained by dividing the average value of the first plurality of pixel values by the value indicated by the dose information. Imaging device. 10. The radiation according to claim 9, wherein the first calibration information is a value obtained by dividing a preset value of radiation detection sensitivity by an average value of sensitivities of the plurality of dose detection pixels. Imaging device. 10. The radiation imaging apparatus according to claim 9, wherein the second calibration information is a value obtained by dividing an average value of sensitivities of the plurality of dose detection pixels by a sensitivity value of each pixel. comprising means for acquiring dose information of the radiation emitted by the radiation generating device from the radiation generating device;
8. The method according to claim 7, wherein the average value of the sensitivities of the plurality of image signal output pixels is a value obtained by dividing the average value of the third plurality of pixel values by the value indicated by the dose information. Radiation imaging device. 13. The method according to claim 12, wherein the third calibration information is a value obtained by dividing a preset value of radiation detection sensitivity by an average value of sensitivities of the plurality of image signal output pixels. Radiation imaging device. 13. The radiographic imaging according to claim 12, wherein a common setting value is used for a setting value for calculating the first calibration information and a setting value for calculating the third calibration information. Device. 13. The radiation imaging apparatus according to claim 12, wherein the fourth calibration information is a value obtained by dividing an average value of sensitivities of the plurality of image signal output pixels by a sensitivity value of each pixel. the panel comprises a plurality of pixel groups;
2. The radiation imaging apparatus according to claim 1, wherein the plurality of dose detection pixels are pixels forming one pixel group out of the plurality of pixel groups. 17. The radiation imaging apparatus according to claim 16, wherein said first calibration information includes a value calculated for each pixel group among said plurality of pixel groups. the panel comprises a plurality of pixel groups;
2. The radiation imaging apparatus according to claim 1, wherein the plurality of dose detection pixels are pixels forming all of the plurality of pixel groups. a radiation imaging apparatus according to any one of claims 1 to 18;
and the radiation generating device for irradiating the radiation imaging device with radiation. 20. The radiographic imaging system according to claim 19, further comprising a display section for displaying radiographic images. 20. The radiographic imaging system according to claim 19, wherein the pre-radiation generator comprises dose measuring means for measuring the dose of the irradiated radiation. The panel is a panel having a first property,
A further radiation imaging device is available comprising a further panel having a second property different from said first property,
20. The radiation imaging system according to claim 19, wherein said panel and said further panel are calibrated according to said first calibration information to have similar output tendencies. A control method for a radiation imaging apparatus comprising a panel comprising a plurality of dose detection pixels for outputting pixel values corresponding to radiation doses, comprising:
first calibration information for calibrating the output of the plurality of dose detection pixels as a whole to a target output common to other devices ; and for calibrating variations in the output of each of the plurality of dose detection pixels a holding step of holding the second calibration information of
a communication step of performing communication processing for stopping irradiation of radiation by the radiation generator;
a determination step of determining execution timing of the communication process based on at least a plurality of pixel values corresponding to the plurality of dose detection pixels, the first calibration information, and the second calibration information;
A control method characterized by having

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