JP2010279403A - X-ray fluoroscopic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform fluoroscopic imaging of an X-ray image at a frame rate set from the start of imaging, and to shorten the time until offset fluctuation is stabilized.
X-rays are emitted from an X-ray generation unit at the start of imaging in accordance with a frame rate set by an operator, and a subject image based on the irradiated X-rays after passing through the subject is detected by a radiation detection unit and read out. Read out from the means, acquire and read out offset data related to the supplied electric signal, and read out the electric signal combined with the subject image and the offset data at the start of shooting, the frame rate is higher than the frame rate set by the operator before shooting Thereafter, the process shifts to shooting of the subject image at the frame rate set by the operator.
[Selection] Figure 2

Description

  The present invention relates to an X-ray fluoroscopic apparatus that converts an X-ray image obtained by a plurality of detection elements arranged in a plane into an electric signal and images the electric signal.

  As an apparatus for imaging X-ray fluoroscopic images in the medical field, I.I. I. X-ray televisions combining an (image intensifier), an imaging tube, and an imaging device such as a CCD have become mainstream. I. I. Converts the X-ray image into a visible image on the phosphor screen, converts the image into photoelectrons at the photocathode, further accelerates and converges with an electron lens, collides with the output phosphor screen, and converts it again into a visible image. I. I. Has a photomultiplier action, and the luminance on the output phosphor screen is amplified to several thousand times that of the input phosphor screen. I. Is generally highly sensitive and contributes to a reduction in patient exposure in fluoroscopic imaging. However, I.I. I. Has an optical system, which causes problems that the image is distorted, the resolution is low, and the apparatus is large.

  In recent years, I.I. I. X-ray fluoroscopy equipped with an FPD (X-ray imaging device: Frat Panel Detector) that converts X-ray signals into electric charges instead of using an X-ray detection device with a fine solid-state imaging device arranged in a two-dimensional grid Devices are beginning to be used in clinical settings. The FPD has less distortion because the image sensors are arranged two-dimensionally, and can obtain a high-resolution X-ray fluoroscopic image because the image sensor can be miniaturized.

  In FPD, an X-ray signal is directly converted into an electrical signal by an a-Se image sensor, and an X-ray signal is converted into visible light by a phosphor, which is converted by an a-Si image sensor. There is an indirect FPD method for converting to an electric signal. The former direct FPD type FPD is converted into an imaging circuit in which a phosphor that converts radiation into visible light and a plurality of solid-state imaging devices that convert visible light into electrical signals are arranged in a two-dimensional grid. A readout circuit for reading out an electrical signal from the imaging circuit.

  In the latter indirect FPD method, X-rays that have passed through the subject are converted into visible light by the phosphor, and charges corresponding to the X-ray dose that has passed through the subject are accumulated in the solid-state imaging device by the photoelectric effect. The accumulated electric charge is read out as an electrical signal to the readout circuit by driving each signal line of the imaging circuit and controlling the switching element connected to the solid-state imaging device, and is further amplified and outputted.

  The electrical signal output from the readout circuit includes subject image information, but the electrical signal also includes an offset component generated in the imaging circuit and the readout circuit. Factors of the offset include (a) dark current of the solid-state imaging device, (b) leakage current of the switching element, (c) offset voltage of the amplifier of the readout circuit, and the like.

  When an electrical signal including an offset is converted into an image, the offset appears on the image, which may cause an artifact, and there is a problem that the dynamic range is compressed by the amount of the offset. The process of improving the image quality by subtracting the offset component from the electrical signal output from the readout circuit is called offset correction.

  There are mainly the following three methods for offset correction in the case of moving image shooting. In the first method, an object image obtained by irradiating X-rays is offset-corrected by using a photographed offset image without irradiating X-rays in another sequence. In the second method, an offset image is first photographed in the same sequence, and then a subject image is photographed by irradiating X-rays, and offset correction is performed using the first photographed offset image. In the third method, a subject image and an offset image are alternately or one offset image is taken every several tens of frames, and offset correction is performed using these offset images.

  The first and second methods have an advantage that the frame rate can be increased because the subject image can be continuously captured after the offset image is captured. On the other hand, the third method has a drawback that the frame rate is lowered because every other offset image is taken or one offset image is taken every several tens of frames.

  In moving image shooting, there is a characteristic that the offset fluctuates with time especially in several tens to several hundred frames immediately after the start of shooting. In Patent Document 1, immediately after the start of imaging in which offset fluctuation occurs, the offset image and the subject image are taken alternately, and then the subject image is continuously taken when the offset is stabilized.

  FIG. 12 is a flowchart showing the operation of the X-ray imaging apparatus of Patent Document 1. m is the number of frames of the offset image from the start of photographing, n is the number of frames of the subject image, X (n) is the subject image, F (m) is the offset image, and Sam is the difference image | F (m ) −F (m−1) |.

  First, at the start of shooting, the offset image F (m) and the subject image X (n) are alternately shot at the frame rate set by the operator, offset correction is performed between both images, and the image is displayed on the monitor or the like. Display on the display means. At this time, the frame rate of only the subject image X (n) is half of the frame rate set by the operator. When the offset fluctuation is stabilized and the maximum value Sam of the difference image falls below the threshold value, the subject image X (n) is continuously photographed at the frame rate set by the operator. The captured subject image X (n) is subjected to offset correction (X (n) by the last captured offset image F (m) in the images obtained by alternately capturing the subject image X (n) and the offset image F (m). n) -F (m)) and display on the display means such as a monitor.

  FIG. 13 is a graph showing an example of the time-series change of the offset component. The time until the fluctuation of the offset becomes stable is determined by the number of frames until the offset becomes stable × the reciprocal of the frame rate. However, since the number of frames until stabilization does not depend on the frame rate fps, the higher the frame rate fps, the shorter the time until the offset fluctuation becomes stable. Further, Patent Document 2 describes a characteristic in which the offset fluctuates with time.

JP 2006-158728 A JP 2002-40144 A

  As described in Patent Document 1, if an offset image and a subject image are alternately shot at the start of shooting, deterioration in image quality due to offset fluctuation at the start of shooting can be suppressed. However, the frame rate of the subject image decreases to half of the value set by the operator until the offset fluctuation is stabilized after the start of shooting.

  Further, when shooting is performed at the frame rate set by the operator at the start of shooting, especially when the operator sets a low frame rate, it takes time until the offset fluctuation is stabilized. Therefore, it takes time to continuously shoot subject images at the frame rate set by the operator.

  The object of the present invention is to solve the above-mentioned problems, enable shooting of a subject image at a frame rate set by an operator from the start of shooting, and shorten the time until the fluctuation of offset at the start of shooting becomes stable. An object of the present invention is to provide an X-ray fluoroscopic apparatus.

  In order to achieve the above object, an X-ray fluoroscopic apparatus according to the present invention comprises an X-ray generating means, an X-ray control means, an image detecting means, an image photographing condition setting means, and an image photographing condition changing means. The change means starts imaging at a frame rate higher than the frame rate set by the setting means, and shifts to the set frame rate as time passes. It is characterized by.

  An X-ray fluoroscopic apparatus according to the present invention includes an X-ray generating unit, an X-ray control unit, an image detecting unit, an image capturing condition setting unit, and an image capturing condition changing unit. An apparatus is characterized in that idle reading of an offset image and shooting of a subject are repeated alternately at the start of shooting.

  According to the X-ray fluoroscopic apparatus according to the present invention, X-ray images can be fluoroscopically captured at a frame rate set from the start of imaging, and the time until offset fluctuation is stabilized can be shortened.

1 is a configuration diagram of an X-ray fluoroscopic apparatus. 3 is a timing chart of the X-ray fluoroscopic apparatus of Embodiment 1. FIG. It is an operation | movement flowchart figure. It is a detailed flowchart figure of a binning change. It is a table | surface of a photography parameter. 6 is a timing chart of Example 2. FIG. It is an operation | movement flowchart figure of prior imaging | photography. It is a graph of the time series change of the pixel value of the offset of each binning at the time of imaging start. It is explanatory drawing of the fluctuation of the offset at the time of imaging | photography start. It is an operation | movement flowchart figure. 6 is a table of imaging parameters of Example 2. It is a flowchart figure of a prior art example. It is explanatory drawing of the time series change of the offset at the time of imaging | photography start.

  The present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 is a configuration diagram of an X-ray fluoroscopic apparatus. The X-ray fluoroscopic apparatus includes an X-ray generation unit that irradiates a subject P with X-rays, an image detection unit that detects X-rays transmitted through the subject P, and a control processing unit that controls the X-ray generation unit and the image detection unit. And.

  The X-ray generation means includes an X-ray generation unit 1 composed of a tube that generates X-rays, a collimator 2 that defines a beam divergence angle of the X-rays generated in the X-ray generation unit 1, and a dosimeter 3. Yes.

  Further, a movable diaphragm 4 is arranged in the collimator 2, and the movable diaphragm 4 is made of a substance such as lead that shields X-rays. By controlling the diaphragm amount of the movable diaphragm 4, The beam divergence angle is controlled. The diaphragm amount of the movable diaphragm 4 is configured to be controlled by a dial attached to the collimator 2. Alternatively, it is controlled by an instruction from an X-ray control means described later.

  The image detection means includes an image detection unit 6 that generates an X-ray image. In addition, the image detection part 6 shall be comprised by arrange | positioning a fine photoelectric conversion element in a two-dimensional grid | lattice form.

  The control processing means includes an arithmetic / control means 7, an imaging condition setting means 8, an imaging condition changing means 9, and an X-ray control means 10. The imaging condition setting unit 8 receives imaging conditions such as a frame rate, tube voltage, and tube current at the time of X-ray imaging from the operator, and sets them in the calculation / control unit 7.

  The calculation / control unit 7 calculates an X-ray irradiation control amount from the imaging conditions set by the imaging condition setting unit 8 and sends an X-ray irradiation control signal to the X-ray control unit 10. The X-ray control means 10 controls the X-ray generation means based on the X-ray irradiation control signal sent from the calculation / control means 7.

  The calculation / control unit 7 sets the drive condition of the image detection unit 6 from the shooting condition set by the shooting condition setting unit 8 and sends an image shooting control signal to the shooting condition changing unit 9. The photographing condition changing means 9 controls the image detecting means based on the image photographing control signal sent from the calculation / control means 7.

  FIG. 2 is a timing chart illustrating an example of the operation of the X-ray fluoroscopic apparatus according to the first embodiment. X-ray irradiation at the time of subject photographing in (a) is controlled by the X-ray control means 10, and the subject P is irradiated with X-rays generated by the X-ray generation means. The X-ray transmitted through the subject P is converted into visible light by the wavelength converter, and the subject image is photographed by reading out the electrical signal photoelectrically converted by the photoelectric conversion element of the image detection unit 6 of the image detection means from the photoelectric conversion circuit. .

  The offset imaging of (b) is an operation of reading an electrical signal of an offset image other than the subject signal such as a dark current of the photoelectric conversion element and an offset voltage in the readout circuit without irradiating the subject P with X-rays.

  The offset average of (c) is an operation of averaging the electrical signals of the read offset images and generating an offset average image.

  The offset correction (d) is an operation for improving the image quality by subtracting the offset component included in the subject image by subtracting the average offset image from the subject image.

  The image display of (e) is an operation for displaying the subject image after offset correction on a display means such as a monitor.

  FIG. 3 is an operation flowchart. By executing this operation, the operation of the X-ray fluoroscopic apparatus according to the first embodiment is realized. FR ′ is a frame rate set by the operator before photographing, m is the number of offset images to be photographed, n is the number of photographed subject images, and k is a frame rate stage of the number of changes. Further, i is a pixel binning (resolution) variable at the time of image capturing, and i = n ′ indicates binning n ′ × n ′. Here, binning n ′ × n ′ is a method of averaging signals of adjacent horizontal n ′ pixels and vertical n ′ pixels of a solid-state imaging device arranged in a two-dimensional grid and reading out as a signal of one pixel. It is. i 'is a binning condition set by the operator.

  In the first embodiment, it is assumed that an offset image for each binning is taken in advance before the operation flowchart of FIG. 3 operates. First, in step S21, the operator sets a desired frame rate FR 'and binning i' for photographing a subject image. In step S22, the frame rate stage k = 0 and the pixel binning variable i = 4 are set. Next, in step S23, the number n of the subject images to be photographed is set to n = 0, and 1 is added to the frame rate stage k every time the frame rate is changed. In step S24, a frame rate FRk at the time of shooting at a high frame rate combining the offset image and the subject image is set, and this frame rate FRk is larger than the frame rate FR 'set by the operator.

  Next, in step S25, the number m of offset images taken is set to m = 0, and 1 is added to the number n of subjects taken every time a subject image is taken. Next, every time an offset image is captured in step S26, 1 is added to the number m of offset image captured. In step S27, an offset image Fkmm with a high frame rate is taken.

  In step S28, a threshold value for the number m of offset images is determined. The threshold value Tk is a constant that controls the number of consecutive shots of the offset image Fkmm, and this threshold value Tk is a number that is preset in the X-ray fluoroscopic imaging apparatus and is different for each frame rate stage k. If the offset image shooting number m is less than the threshold value Tk in step S28, the process returns to step S26 again to repeat the offset shooting, and the offset shooting is performed until the offset image shooting number m reaches the threshold value Tk before proceeding to step S29.

  In the example of FIG. 2, after taking three offset images at each frame rate step k of T1 = 3 and T2 = 1, the process proceeds to step S29.

  After the offset shooting, in step S29, an average image Fkn = (1 / Tk) ΣFknm of the offset image Fknm shot in step S27 is created. In the example of FIG. 2, the average of F11 = (1/3) × (F111 + F112 + F113), F12 = (1/3) × (F121 + F122 + F123) at frame rate stage k = 1, F21 = F211 and F22 = F221 at k = 2. Creating an image.

  In step S30, the subject P is irradiated with X-rays from the X-ray generation unit, and the subject image Xkn is captured at a high frame rate. At this time, the X-ray generation means and the image detection means are synchronized, and the X-rays are emitted in a pulse shape and are emitted only within the subject photographing time. This reduces ineffective exposure and leads to a lower exposure dose for the patient. Here, the frame rate of the subject image shooting excluding the offset image shooting is the frame rate FR ′ set by the operator.

  In step S31, offset correction is performed, and the offset image Xkn photographed in step S27 and averaged in step S29 is subtracted from the subject image Xkn photographed in step S30, and calculation of (Xkn-Fkn) is performed.

  In step S32, the subject image (Xkn-Fkn) after offset correction is displayed on the display means. Since the subject image after the offset correction has a small time difference between the subject image and the offset image, the offset component included in the subject image is accurately subtracted. As a result, the operator can obtain a high-quality image in which the offset is accurately subtracted at a desired frame rate FR ′ from the start of shooting with a large offset fluctuation. Further, averaging the offset images also has an effect of reducing noise included in the subject image after offset correction.

  In step S33, the number n of photographed subject images is compared with a threshold value Tk 'of the number n of photographed subject images at each frame rate step k. The threshold value Tk ′ is determined by each frame rate step k and is set in advance by a setting unit. If the frame number n is smaller than the threshold value Tk ', the process returns to step S25, and offset image shooting, offset image averaging, subject image shooting, offset correction, and subject image display in steps S27 to S32 are performed again. If the frame number n is greater than or equal to the threshold value Tk ', the process proceeds to step S34.

  In step S34, a comparison is made between the frame rate stage k and a frame rate change threshold T ″ that is a preset constant for shifting to shooting at the frame rate FR ′ set by the operator. If k is less than the threshold value T ″, the process proceeds to step S35. If k ≧ T ″ in step S35, the process proceeds to step S36. Step S35 is a binning change step, and binning is changed according to the frame rate stage k.

  FIG. 4 is a detailed flowchart of the binning change in step S35. In step S35a, the frame rate stage k is compared with the transition threshold T ′ ″ 22 for binning 2 × 2 shooting. If the frame rate stage k is less than the threshold T ′ ″ 22, the process proceeds to step S35b, the image capturing condition is set to binning 4 × 4 (i = 4), and the frame rate stage k is greater than or equal to the threshold T ′ ″ 22. If so, the process proceeds to step S35c.

  In step S35c, the frame rate stage k is compared with the threshold T ′ ″ 11 for shifting to binning 1 × 1. If the frame rate step k is less than the threshold T ′ ″ 11, the image capturing condition is set to binning 2 × 2 (i = 2) in step S35d, and if the frame rate step k is greater than or equal to the threshold T ′ ″ 11. In step S35e, the photographing condition is set to binning 1 × 1 (i = 1).

  After the binning change in step S35, the process returns to step S23, and offset image shooting, offset image averaging, subject image shooting, offset correction, and subject image display are repeated.

  In step S36, an offset image F used when offset correction is performed on the subject image captured at the frame rate FR ′ set by the operator, and imaging at the frame rate FR ′ set by the operator is referred to as continuous imaging. When the binning in the continuous shooting and the binning in the shooting at the immediately preceding frame rate FRT ″ are the same, the offset image F used in the continuous shooting is the offset average image F = FT ″, T′T ″ immediately before the continuous shooting. In addition, when the binning in the continuous shooting and the binning in the shooting at the immediately preceding frame rate FRT ”are different from each other, the offset image is taken by the same binning as the continuous shooting previously taken before the shooting is started.

  In step S37, 1 is added to the frame rate stage k, and in step S38, the frame rate is set to a desired frame rate FR ′ set before the start of shooting by the operator, and is set to shoot only the subject image. .

  The loop of steps S39 to S43 is a continuous shooting step, and this continuous shooting step is repeated until shooting is completed. In step S40, 1 is added to the number n of photographed subject images every time the subject images are photographed. In step S41, the subject P is irradiated with X-rays and a subject image Xkn is photographed. In step S42, the subject image Xkn photographed in step S41 is offset-corrected with the offset image F determined in step S36. In step S43, the subject image (Xkn-F) corrected for offset in step S42 is displayed on the display means. By repeating Steps S40 to S43, the operator can obtain a subject image excluding the offset component at a desired frame rate FR ′.

  FIG. 5 is a parameter table of the flowchart of FIG. 3 for executing an example of the first embodiment shown in FIG. In the first embodiment, the frame rate of the offset image and the subject image is 120 fps, but the subject image is taken at 30 fps. Generally, there is a limit to the frame rate that can be displayed on the display means. Therefore, when photographing is performed at a frame rate higher than the frame rate FR ′ set by the operator at the start of photographing and the offset fluctuation is quickly stabilized, the subject P is irradiated with X-rays in all frames. If an image is taken, a frame that cannot be displayed is generated.

  In the first embodiment, in response to such a problem, a plurality (or one) of offset images and a subject image are photographed alternately, and the frame rate of the subject image photographing is set to be equal to or lower than the displayable frame rate of the display unit. This prevents invalid exposure.

  Further, in FIG. 2, at any frame rate step k at the frame rate of the subject image at the start of photographing, the subject image is taken at a desired frame rate FR ′, and the subject image is displayed at this frame rate FR ′. Is displayed. As a result, when the frame rate step k is switched or when switching to continuous shooting of the subject image at the frame rate FR ′ set by the operator, the frame rate FR ′ of the subject image display is different for the operator. The uncomfortable feeling that occurs can be eliminated. Also, as shown in FIG. 2, the instability of the image caused by a sudden change in the frame rate can be reduced by shifting the frame rate step by step to the frame rate FR ′ set by the operator. it can.

  In general, in an FPD imaging device, it takes time to scan an electrical signal after photoelectric conversion from each element, and there is a limit to a transfer speed at which a signal is transferred to an information processing device such as a PC. Therefore, there is a problem that FPD cannot scan and transfer a certain binning image at a certain frame rate or higher.

  On the other hand, in the first embodiment, the operator sets shooting with binning 1 × 1 as shooting conditions. However, when shooting is started, shooting is performed at a binning of 4 × 4 and a frame rate of 120 fps, and then shooting is performed at a binning of 2 × 2 and 60 fps. Even if the upper limit of the image capturing performance of the fluoroscopic imaging device is 30 fps with binning of 1 × 1, by starting binaring and shooting at a high frame rate as time passes, Images can be stabilized quickly.

  In general, in a moving image photographing device, heat is gradually generated by the power consumed by the circuit from the start of photographing, the temperature of the photographing device gradually rises, and the image that is taken becomes stable as the temperature becomes constant over time. . Since the offset component and the like of the captured image are unstable while the temperature is rising, in the first embodiment, binning is performed at the start of shooting and shooting at a frame rate higher than the frame rate set by the operator is performed. It is carried out. As a result, the amount of heat generated by the X-ray fluoroscopic imaging apparatus during that time is greater than that when imaging is performed at the frame rate set by the operator, so that the time required until the temperature of the imaging apparatus is stabilized can be shortened.

  FIG. 6 is a timing chart of the operation of the X-ray fluoroscope according to the second embodiment. In this second embodiment, the idle reading is performed at the start of photographing to stabilize the offset earlier than in the first embodiment. In the second embodiment, an offset image is taken in a different sequence before the main shooting, and an offset image at the time of the main shooting is obtained by simulation from the offset image and the amount of fluctuation of the offset, and offset correction is performed.

  In the timing chart of FIG. 6, the offset idle reading of (f) is performed instead of the offset photographing of (b) of FIG. In this offset idle reading, an electrical signal other than the subject signal such as the dark current of the photoelectric conversion element and the offset voltage in the readout circuit is read without being transferred to the signal processing means. Further, an offset image taken in advance is used as the offset image, and an offset image at the time of actual photographing is obtained from the offset image by simulation.

  The idle reading can increase the frame rate as compared with the offset photographing. In FIG. 6, the idle reading at the binning 4 × 4 is 300 fps, and the idle reading at the binning 2 × 2 is 75 fps.

  FIG. 7 is a flowchart of offset image shooting before the start of main shooting in the second embodiment. In offset image shooting before the start of main shooting, an offset image is shot for each binning, and an offset fluctuation amount at the start of shooting and an average image of the offset images after the offset is stabilized are obtained.

  In step S51, the frame rate of offset image shooting in advance is set to 30 fps. This frame rate is a value set in the X-ray fluoroscopic apparatus, 30 fps is an example, and i is the number of binning changes at the time of offset image shooting. If i = n, offset image shooting is set to be binned n × n. In addition, p is the number of frames from the start of capturing the offset image, and the captured offset image Fip indicates the p-th image captured by binning i × i. The offset image F′ip is an image obtained by adding the offset images Fi1 to Fip, and F′i is an average image of (Tb2−Tb1 + 1) offset images of F′iTb1 to F′iTb2 after the fluctuation of the offset is stabilized. Represents.

  Here, Tb1 is a threshold value of the number of frames of the offset image until the offset fluctuation is stabilized, and Tb2 is a threshold value for controlling the photographing, addition, and average number of the offset images after the offset fluctuation is stabilized. In step S57, the average value Ofip of the offset image Fip when the offset is unstable is calculated, and in step S68, the average value phi of the pixel value when the offset is stable is calculated. Ofip in step S63 is a value obtained by subtracting the average value of the pixel values of the offset image after the offset of the image is stabilized from the Ofip in step S57, and represents the amount of fluctuation at the start of offset imaging.

  In FIG. 7, the offset image Fip is photographed for each binning, and the offset image photographing number p is compared with the threshold value Tb1 in step S56. If the number p of offset image shots is smaller than the threshold value Tb1, the average value of pixel values of the image (the amount of offset fluctuation) is obtained. If the offset image shooting number p is larger than the threshold value Tb1, the offset images shot until the offset image shooting number p reaches the threshold value Tb2 are added, and this is divided by the added number to obtain the subject image in the actual shooting. Generate an offset image.

  In FIG. 7, an offset image is taken by binning to an integer power of 2, and the amount of fluctuation of the offset image at the start of photographing and the average image of the offset image after the fluctuation of the offset is stabilized until the binning reaches the threshold value Tb3 or more. Looking for.

  In FIG. 7, these values are values set in advance in the X-ray generator. For example, a threshold value is provided for the difference | Fip-Fip-1 | It may be determined from the amount. Further, although binning is performed by an integer power of 2, the binning number may be an arbitrary integer.

  FIG. 8 is a graph showing the time-series change of the pixel value of the offset of each binning at the start of photographing obtained as described above. FIG. 9 shows the amount of offset fluctuation at the start of photographing, which is obtained by subtracting the average value of the offset after the offset fluctuation is stabilized from the pixel value.

  FIG. 10 is an operation flowchart of the X-ray fluoroscopic apparatus according to the second embodiment. In the following, points different from the flowchart of FIG. 3 will be described. In FIG. 10, p is the total number of shots of blank reading and the number of shots of subject images, and is 1 every time blank reading or subject image shooting is performed. Is added. In step S77, idle reading of the offset image when the offset is unstable is performed. In step S80, the offset image Fkn at the start of photographing is simulated by adding the offset fluctuation amount Ofip at the start of photographing to the offset image F′i for each binning obtained in advance photographing. is doing. In step S81, the offset correction of the photographed subject image Xkn is performed using the offset image Fkn obtained by the simulation.

  FIG. 11 is a shooting parameter in the flowchart of the pre-shooting in FIG. 7 for obtaining the result of the second embodiment. Further, the shooting parameters in the flowchart of FIG. 10 for performing the operation of the timing chart of FIG. 6 are the same as the shooting parameters shown in FIG.

  In the second embodiment, the time until the offset fluctuation is stabilized can be shortened compared to the first embodiment. In addition, even at the start of shooting where the offset fluctuates, offset correction at the time of main shooting can be accurately performed without shooting an offset image at the time of main shooting.

  In addition, an Example is an example in implementing this invention, The technical scope of this invention is not necessarily limited by an Example, This invention performs various changes etc. within the range of the summary. be able to.

DESCRIPTION OF SYMBOLS 1 X-ray generation part 2 Collimator 3 Dosimeter 4 Movable diaphragm 5 Imaging part 6 Image detection part 7 Calculation / control means 8 Imaging condition setting means 9 Imaging condition change means 10 X-ray control means FR Frame rate FR 'An operator sets Frame rate Fkn Offset image Xkn Subject image F Average image m Number of offset images captured n Number of subject images captured

Claims (7)

  An X-ray fluoroscopic apparatus comprising: an X-ray generation unit; an X-ray control unit; an image detection unit; an image capturing condition setting unit; and the image capturing condition changing unit. An X-ray fluoroscopic imaging apparatus, wherein image capturing is started at a frame rate higher than a frame rate set by a setting means, and transitions to the set frame rate as time elapses.   An image display means is provided, and an image generated from images taken at the two frame rates is displayed on the image display means in accordance with the set image shooting conditions or the performance of the image display means. The X-ray fluoroscopic apparatus according to claim 1.   The X-ray fluoroscopic apparatus according to claim 1, wherein the image detection unit and the X-ray generation unit are synchronized.   The X-ray fluoroscopic apparatus according to claim 1, wherein the frame rate is shifted in stages.   The X-ray fluoroscopic imaging apparatus according to claim 1, further comprising: a binning unit that performs imaging at a frame rate higher than a frame rate that can be imaged when binning is not performed.   An X-ray fluoroscopic apparatus having an X-ray generation unit, an X-ray control unit, an image detection unit, an image capturing condition setting unit, and the image capturing condition changing unit, An X-ray fluoroscopic imaging apparatus characterized by alternately repeating idle reading and subject imaging.   7. The X-ray fluoroscopy according to claim 6, further comprising: an offset correction unit, wherein a value obtained by simulation is used for offset correction of a captured image based on the offset image captured in another sequence. Shooting device.

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