JP2010004959A - X-ray ct apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To position a phantom with high accuracy. <P>SOLUTION: A scan execution part 31c controls respective parts to photograph the phantom under a scan condition suited to the size of the phantom which has received a positioning instruction. A calculation part 32a reconstructs projection data transmitted from a data gathering part 25 and generates tomographic image data. The calculation part 32a selects FOV (Field Of View) suited to the size of the phantom which has received a positioning instruction, and calculates a reference position. The calculation part 32a calculates the inclination and moving amount of the phantom from the calculated reference position and the projection data transmitted from the data gathering part 25. A display control part 32b displays an image based on the generated tomographic image data at an image display part 42, also superimposes the information of the calculated inclination and moving amount of the phantom and the information and scale indicating the reference position when the phantom is correctly installed on the image, and displays them. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an X-ray CT apparatus, and more particularly to an X-ray CT apparatus capable of highly accurately aligning a phantom for an X-ray CT apparatus having a multi-row X-ray detector.

  An X-ray CT (Computed Tomography) apparatus generates an X-ray beam by an X-ray source, detects an X-ray beam transmitted through a subject on a bed by an X-ray detector, and generates X-ray projection data. By performing reconstruction processing on the line projection data, two-dimensional tomographic image data representing the internal form of the subject can be generated.

  In order to acquire highly accurate tomographic image data, it is necessary to periodically evaluate the performance of the X-ray CT apparatus. And when performance falls, adjusting X-ray CT apparatus is performed in order to maintain performance.

  In the performance evaluation of the X-ray CT system, correction data is collected using a pseudo object called a phantom that simulates the human body instead of the actual human body, and the resolution is evaluated from the collected correction data for calibration. Execute.

  The phantom is made of, for example, a hollow cylindrical object, and the hollow portion is filled with a filler such as water. In order to ensure the accuracy of performance evaluation using this phantom, the phantom must be arranged at a suitable installation position of the X-ray CT apparatus.

  Conventionally, alignment of phantoms has been performed as follows. For example, as shown in FIG. 14, as preparation for imaging the phantom 100, the folder 102 is set on the top plate 101 on which the subject of the X-ray CT apparatus is placed, and the phantom 100 is fixed to the folder 102. After making such preparation, the phantom 100 is placed at the center of the examination region of the X-ray CT apparatus, imaging is performed, and tomographic image data is reconstructed and displayed.

  The operator adjusts the window width and the window level so that the phantom is clearly displayed while observing the tomographic image. Next, how much the center position of the tomographic image is displaced in which direction is specified by an eye quantity. Then, the installation position of the phantom is moved by the specified amount, and the tomographic image is observed again to confirm the moved position. By repeating such a series of operations, the phantom is arranged at the target position.

Such a series of operations requires time and labor, and the burden on the operator is large. Thus, for example, Patent Document 1 proposes a technique that can easily and quickly align the phantom.
JP 2007-222599 A

  In the conventional X-ray CT apparatus, since the size of the phantom used for collecting correction data in the body axis direction is small, it is not necessary to consider the inclination of the phantom when installing the phantom.

  However, in recent years, with the increase in the number of detector rows, the size of the phantom used has increased. For this reason, in addition to the phantom alignment, it has been necessary to adjust the horizontal displacement and vertical displacement.

  In the technique of Patent Document 1 described above, there has been a problem that the horizontal displacement and the vertical displacement cannot be displayed, and the phantom cannot be aligned with higher accuracy.

  The present invention has been made in view of such a situation, and an object thereof is an X-ray capable of performing phantom alignment with high accuracy in an X-ray CT apparatus having a multi-row X-ray detector. A CT apparatus is provided.

  According to a first aspect of the present invention, there is provided an X-ray CT apparatus having an X-ray tube for irradiating X-rays and a multi-row X-ray detector, around a phantom which is a case filled with a filling. Imaging control means for collecting projection data by rotating an X-ray tube and an X-ray detector, reconstruction means for reconstructing a tomographic image based on the projection data of the phantom, and the vicinity of the end of the phantom in the tomographic image The image generation means for extracting the images of the plurality of areas set in the above, and generating the image for tilt confirmation by combining the images of the plurality of areas, and the display control means for displaying the image for tilt confirmation.

  A feature of the invention described in claim 5 is that, in an X-ray CT apparatus having an X-ray tube for irradiating X-rays and a multi-row X-ray detector, a phantom and an X-ray which are casings filled with a filler An imaging control unit that relatively translates the tube to collect projection data, a reconstruction unit that reconstructs a tomographic image based on the projection data of the phantom, a calculation unit that calculates the inclination and movement amount of the phantom, Display control means for displaying, together with the tomographic image, information indicating the inclination and movement amount of the phantom.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform the alignment of the phantom for X-ray CT apparatuses which have the X-ray detector made into multiple rows with high precision.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration example of an X-ray CT apparatus 1 according to the present invention. The X-ray CT apparatus 1 includes a gantry 2, a computer apparatus 3, and a console 4.

  The gantry 2 incorporates a rotatable support 21. An X-ray tube 22 and an X-ray detector 23 are supported on the support 21. The support 21 rotates around the subject P placed on the bed 24 by a drive unit (not shown). The X-ray tube 22 and the X-ray detector 23 rotate around the subject P as the support 21 rotates.

  The X-ray tube 22 generates X-rays based on a predetermined tube voltage and tube current applied by a high voltage generator (not shown), and rotates around the subject P while moving to the bed 24 of the gantry 2. This X-ray is exposed toward the subject P to be placed.

  The X-ray detector 23 is supported at a position facing the X-ray tube 22 and detects the X-ray dose of the X-ray beam transmitted through the subject P. The X-ray detector 23 is configured as a multi-channel detector having a plurality of channels and a plurality of columns in which a plurality of X-ray detection channels are arranged in a two-dimensional matrix. The detected transmitted X-ray dose data is output to the data collection unit 25.

  The data collection unit 25 is called a so-called DAS (Data Acquisition System), has a plurality of data collection element arrays in which DAS chips are arranged, and collects transmission X-ray dose data detected by the detector 23. The data collection unit 25 performs amplification processing, A / D (Analog to Digital) conversion processing, and the like on the collected transmitted X-ray dose data, and then transmits the data to the image reconstruction unit 32 of the computer apparatus 3.

  The computer apparatus 3 includes a general-purpose computer on which a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disc Drive), and the like are mounted. Control all parts centrally. Further, the computer device 3 includes an interface for transmitting and receiving data and signals between the gantry 2 and the console 4.

  The computer device 3 includes an imaging control unit 31 that controls the operation of each unit of the gantry 2, an image reconstruction unit 32 that performs image data generation processing and various image processing based on data collected by the gantry 2, and a program And a data storage unit 33 for storing various data.

  The imaging control unit 31 controls the rotation operation of the support 21, the operation control of the X-ray tube 22, the operation control of the X-ray detector 23, and the operation of the data collection unit 25 based on the input signal from the operation console 41. Perform control and so on.

  The image reconstruction unit 32 reconstructs the projection data transmitted from the data collection unit 25 based on predetermined reconstruction parameters such as a reconstruction region size, a reconstruction matrix size, and a threshold value for extracting a region of interest. Configuration processing is performed to generate tomographic image data for a predetermined slice. The image reconstruction unit 32 displays a tomographic image based on the generated tomographic image data on the image display unit 42 of the console 4. The image reconstruction unit 32 stores the projection data transmitted from the data collection unit 25 and the generated tomographic image data in the data storage unit 33.

  The console 4 is provided with an operation console 41 that receives input from an operator and an image display unit 42 that displays an image.

  The operation console 41 is composed of, for example, a keyboard and a mouse, and outputs a signal in response to an operator input to the imaging control unit 31. The image display unit 42 is composed of, for example, a liquid crystal display, and displays a tomographic image based on the tomographic image data generated by the image reconstruction unit 32.

  The X-ray CT apparatus 1 having the above-described configuration uses a pseudo object called a phantom having a casing filled with a filling material such as water, in order to maintain the apparatus performance. The calibration is performed by evaluating the spatial resolution, slice thickness, high contrast resolution, low contrast resolution, and the like.

  For example, as shown in FIG. 2, the phantom 100 fixed to the folder 102 is photographed to collect correction data, and the apparatus performance is evaluated from the collected correction data to execute calibration. The X-ray CT apparatus 1 is also configured to display an image for positioning the phantom 100 in order to accurately evaluate the performance. Details of the display example of this image will be described later.

  FIG. 3 is a block diagram illustrating a functional configuration example of the computer apparatus 3 of the X-ray CT apparatus 1. At least a part of the functional units shown in FIG. 3 is realized by reading an alignment control program or the like into the CPU.

  The imaging control unit 31 has functions of an operation detection unit 31a, a scan condition selection unit 31b, and a scan execution unit 31c, and the image reconstruction unit 32 has functions of a calculation unit 32a and a display control unit 32b.

  The imaging control unit 31 serves as an imaging control unit that controls the data collection unit 25 to collect projection data by rotating the X-ray tube and the X-ray detector around the phantom 100. The imaging control unit 31 also serves as imaging control means for controlling the phantom 100 and the X-ray tube to move relative to each other and cause the data collection unit 25 to collect projection data.

  The image reconstruction unit 32 serves as reconstruction means for reconstructing a tomographic image based on phantom projection data.

  When the operation detection unit 31 a detects an instruction for executing alignment of the phantom 100 from the input signal supplied from the operation console 41, the operation detection unit 31 a supplies the detection result to the scan condition selection unit 31 b and the calculation unit 25. When the operation detection unit 31a detects an instruction for displaying various operation screens from the input signal supplied from the operation console 41, the operation detection unit 31a supplies the detection result to the display control unit 32b.

  Based on the detection result supplied from the operation detection unit 31a, the scan condition selection unit 31b scans in accordance with the size of the phantom 100 that has been instructed from among the scan conditions for alignment stored in advance. A condition is selected, and the selected scan condition is supplied to the scan execution unit 31c.

  The scan execution unit 31c controls each unit of the gantry 2 so that the phantom 100 is imaged under the scan conditions supplied from the scan condition selection unit 31b. Specifically, the scan execution unit 31c performs control so that the X-ray tube 21 is fixed at rotation angles of 0 degrees and 90 degrees and the top plate 24 is moved to scan a wide range.

  The calculation unit 32a reconstructs the projection data transmitted from the data collection unit 25 to generate tomographic image data. Further, the calculation unit 32a extracts images of a plurality of areas (for example, a plurality of images set in the vicinity of the end of the phantom 100) from the generated tomographic image data, and combines the extracted images for inclination confirmation. It functions as an image generation means for generating an image.

  Further, based on the detection result supplied from the operation detection unit 31a, the calculation unit 32a matches the size of the phantom 100 that has been instructed for alignment from among information related to FOV (Field Of View) stored in advance. Select FOV and calculate the reference position.

  The calculation unit 32 a functions as a calculation unit that calculates the tilt and the movement amount of the phantom 100 from the calculated reference position and the projection data transmitted from the data collection unit 25.

  Specifically, the calculation unit 32 a uses the difference between the CT value of the tomographic image corresponding to the phantom 100 and the CT value of the tomographic image corresponding to the air around the phantom 100, Pixels of a tomographic image corresponding to the phantom 100 are extracted. Then, the calculation unit 32a calculates the inclination by searching for the contour of the phantom 100 from the extracted pixels, and calculates the movement amount by counting the extracted pixels.

  The tomographic image data generated by the calculation unit 32 and the calculated tilt and movement amount information of the phantom 100 are supplied to the display control unit 32b.

  The display control unit 32b functions as a display control unit that causes the image display unit 42 to display an image for tilt confirmation based on the tomographic image data supplied from the calculation unit 32a. The display control unit 32 superimposes and displays the tilt and movement amount information supplied from the calculation unit 32a and the information and scale (scale) indicating the reference position when the phantom 100 is correctly installed.

  The display control unit 32b displays various operation screens on the image display unit 42 based on the detection result supplied from the operation detection unit 31a.

  Next, a display example of an image for aligning the phantom 100 will be described.

  FIG. 4 and FIG. 5 show display examples of scanograms (planar transmission images) photographed for positioning the phantom 100. FIG. 4 shows a display example of a scanogram when the X-ray tube 21 is at 0 degrees, and FIG. 5 shows a display example of a scanogram when the X-ray tube 21 is at 90 degrees.

  4 and 5 includes a tomographic image 24a corresponding to the top plate 24, a tomographic image 100a corresponding to the phantom 100, and a tomographic image 102a corresponding to the folder 102. Yes. The background area around the tomographic image 24a, the tomographic image 100a, and the tomographic image 102a corresponds to the air around the top plate 24, the phantom 100, and the folder 102.

  In addition, on the scanogram, the tilt (tilt) and the amount of movement (deviation or sag) of the phantom 100 calculated by the calculation unit 32a are superimposed and displayed.

  By displaying a scanogram when the X-ray tube 21 is 0 degrees as shown in FIG. 4 and a scanogram when the X-ray tube 21 is 90 degrees as shown in FIG. The inclination with respect to the position and the amount of movement from the installation reference position can be easily confirmed.

  FIG. 6 shows a display example (display example of a multi-section reconstruction image) of an MPR (Multi Planer Reconstruction) image photographed for aligning the phantom 100.

  In the display example of FIG. 6, the MPR axial image 100b corresponding to the phantom 100 is displayed at the upper left of the screen, the coronal image 100c is displayed at the upper right of the screen, and the sagittal image 100d is displayed at the lower left of the screen. Has been. In these MPR images 100b to 100d, a reference line that is the center position when the phantom 100 is correctly installed is displayed in a cross direction with a dotted line in the figure, and the reference position when the phantom 100 is correctly installed is shown in the figure. It is displayed with a bold line.

  In addition, information on the tilt and movement amount of the phantom 100 calculated by the calculation unit 32a is superimposed and displayed on the lower right side of the screen.

  By displaying the MPR image as shown in FIG. 6, the amount of movement from the installation reference position of the phantom 100 can be confirmed from the axial image 100b, and the right and left inclinations from the coronal image 100c to the installation reference position of the phantom 100 The vertical inclination of the phantom 100 with respect to the installation reference position can be confirmed from the sagittal image 100d.

  FIG. 7 and FIG. 8 show display examples of axial images taken for positioning the phantom 100.

  In the display examples of FIGS. 7 and 8, two axial images at distant slice positions are displayed. For example, as shown in FIG. 9, when the slice position at the front end of the phantom 100 in the Z direction (body axis direction) is 1 row and the slice position at the rear end is Xrow, the axial image 100b-1 at the slice position 1row Is displayed on the left side of the screen, and the axial image 100b-x at the slice position Xrow is displayed on the right side of the screen. In addition, a reference line serving as a center position when the phantom 100 is correctly installed is displayed in a cross direction as a dotted line in the figure.

  In the display example of FIG. 7, since the phantom 100 matches the installation reference position, the axial images 100b-1 and 100b-x are displayed at the center position of the reference line indicated by the dotted line in the drawing.

  In the display example of FIG. 8, the phantom 100 is aligned with the installation reference position at the front end, but is shifted toward the rear end, so that the axial image 100b-1 at the slice position 1row is displayed at the center position of the reference line. However, the axial image 100b-x at the slice position Xrow is displayed shifted from the center position.

  In this way, by displaying two axial images at distant slice positions as shown in FIGS. 7 and 8, it is possible to easily confirm the deviation of the phantom 100 from the installation reference position.

  Further, when the operator uses the operation console 41 to instruct the enlarged display in the state where the axial image shown in FIGS. 7 and 8 is displayed, the partial enlarged display as shown in FIGS. 10 and 11 is performed. It is also possible to perform.

  FIG. 10 is a diagram for explaining a display example when an enlarged display is instructed while the axial image shown in FIG. 7 is displayed. FIG. 11 shows the display of the axial image shown in FIG. It is a figure explaining the example of a display when enlarged display is instructed in the state.

  In the case of the example in FIG. 10, areas A1 to A4 that include regions intersecting the reference position in the axial image 100b-1 at the slice position 1row are enlarged, and the reference position in the axial image 100b-x at the slice position Xrow. Each of the areas A5 to A8 including the region intersecting with is enlarged. When the enlargement process is performed, the display is switched to the display of the image at the tip indicated by the white arrow in the figure. In these partially enlarged axial images, a reference line that is the center position when the phantom 100 is correctly installed is displayed in a cross direction as a dotted line in the figure, and the reference position when the phantom 100 is correctly installed is displayed. A thick line is displayed in the figure, and a scale for alignment is also displayed.

  In the display example of FIG. 10, since the phantom 100 matches the installation reference position, the axial images 100b-1 and 100b-x are partially enlarged and displayed at the center position of the reference line indicated by the dotted line in the drawing.

  Similarly, in the example of FIG. 11, the areas A1 to A4 of the axial image 100b-1 are enlarged, and the areas A5 to A8 of the axial image 100b-x are enlarged. When the enlargement process is performed, the display is switched to the display of the image at the tip indicated by the white arrow in the figure.

  In the display example of FIG. 11, the phantom 100 is aligned with the installation reference position at the front end, but is shifted toward the rear end, so that the axial image 100b-1 at the slice position 1row is partially enlarged at the center position of the reference line. Although displayed, the axial image 100b-x at the slice position Xrow is partially enlarged and shifted from the center position.

  In this way, by magnifying and displaying the portions intersecting the reference positions of the two axial images at the distant slice positions as shown in FIG. 10 and FIG. 11, the displacement of the phantom 100 from the installation reference position is more detailed. Can be confirmed. The operator can easily read the shift of the enlarged image from the scale.

  Next, display control processing for positioning the phantom 100, which is executed by the computer apparatus 3, will be described with reference to the flowchart of FIG. This process is performed to adjust the phantom 100 to a suitable installation position when the operator uses the operation console 41 to instruct correction data collection for performing performance evaluation of the X-ray CT apparatus 1.

  When the operation detection unit 31a detects an instruction for displaying the correction data collection screen from the input signal supplied from the operation console 41, the operation detection unit 31a supplies the detection result to the display control unit 32b.

  In step S1, the display control unit 32b displays a correction data collection screen used for evaluating the performance of the X-ray CT apparatus 1 based on the detection result supplied from the operation detection unit 31a.

  FIG. 13 is a diagram illustrating a display example of the correction data collection screen 51.

  The correction data collection screen 51 displays scan mode selection items and FOV selection items. The operator can select a predetermined scan mode or FOV from the selection items. Yes.

  When the operator selects the size of the phantom 100 for collecting correction data, a dialog box 52 is displayed. In this dialog box 52, the message “Do you want to align the phantom?”, The “OK” button 53 selected when aligning the phantom 100, and the alignment of the phantom 100 are already performed. A “Cancel” button 54 is displayed, which is selected when it is canceled.

  In step S2, the operation detection unit 31a determines whether or not the operator has instructed the alignment of the phantom 100. That is, in the correction data collection screen 51 shown in FIG. 13, it is determined whether or not the size of the phantom 100 for collecting correction data is selected and the “OK” button 53 is selected.

  When the “Cancel” button 54 is selected on the correction data collection screen 51 shown in FIG. 13, the phantom 100 has already been aligned, and correction data collection processing is performed as the next processing.

  If it is determined in step S2 that the alignment of the phantom 100 has been instructed, the process proceeds to step S3, and the calculation unit 32a is stored in advance based on the phantom alignment instruction supplied from the operation detection unit 31a. From the information about the FOV, an FOV that matches the size of the phantom 100 for which the alignment instruction has been given is selected, and a reference position is calculated.

  For example, when the positioning of the “L” size phantom 100 is instructed, a slightly larger “LL” size FOV is selected, and a reference position determined by the “LL” size FOV is calculated.

  In step S4, the scan condition selection unit 31b has received an instruction for alignment from the pre-stored scan conditions for alignment based on the phantom alignment instruction supplied from the operation detection unit 31a. A scan condition that matches the size of the phantom 100 is selected.

  In step S5, the scan execution unit 31c controls each unit of the gantry 2 so that the phantom 100 is imaged under the scan condition selected in step S4. As a result, each part of the gantry 2 is driven, and the data collection unit 25 collects the data of the transmitted X-ray amount detected by the detector 23 and transmits the collected data to the image reconstruction unit 32.

  In step S <b> 6, the calculation unit 32 a acquires the image data transmitted from the data collection unit 25.

  In step S7, the calculation unit 32a calculates the inclination of the phantom 100 from the reference position calculated in the process of step S3 and the image data acquired in the process of step S6. That is, a pixel is extracted from the difference between the CT value of the tomographic image of the phantom 100 and the CT value of the tomographic image around the phantom 100, the contour of the phantom 100 is searched from the extracted pixel, and the inclination is calculated.

  In step S8, the calculation unit 32a calculates the movement amount of the phantom 100 from the reference position calculated in the process of step S3 and the image data acquired in the process of step S6. That is, the pixels of the tomographic image of the phantom 100 extracted in the process of step S7 are counted, and the movement amount is calculated.

  In step S9, the display control unit 32b displays an image based on the image data acquired in the process of step S6 on the image display unit 42, and the inclination and movement amount of the phantom 100 calculated in the processes of step S7 and step S8. The information is superimposed and displayed. As a result, the images as shown in FIGS. 4 to 8 are displayed on the image display unit 42, so that the operator can easily confirm the deviation of the phantom 100 from the installation reference position. Further, the operator can read more detailed deviation from the scale by performing the partial enlarged display as shown in FIGS. 10 and 11 as necessary. Further, the operator can smoothly adjust the installation position of the phantom 100 based on the movement amount read from the scale. And if the phantom 100 is installed in the suitable position of the X-ray CT apparatus 1, the correction data collection process for performing the performance evaluation of the X-ray CT apparatus 1 will be performed.

  As described above, by applying the present invention, even if the phantom for evaluating the performance of the X-ray CT apparatus having multi-row detectors becomes large, the phantom is accurately aligned. And performance evaluation can be performed with high accuracy.

  Note that the present invention is not limited to the above-described embodiment as it is, and in the implementation stage, the constituent elements may be modified and embodied without departing from the scope of the invention, or a plurality of configurations disclosed in the above-described embodiment may be used. Various inventions can be formed by appropriately combining elements. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

It is a figure which shows the structural example of the X-ray CT apparatus which concerns on this invention. 1 is an external perspective view of an X-ray CT apparatus when a phantom is placed on a top board. It is a figure which shows the function structural example of a computer apparatus. It is a figure which shows the example of a display of a scano image. It is a figure which shows the other example of a display of a scano image. It is a figure which shows the example of a display of a MPR image. It is a figure which shows the example of a display of an axial image. It is a figure which shows the other example of a display of an axial image. It is a schematic perspective view showing the state of a phantom. It is a figure which shows the example of a partial expansion display of the image of FIG. It is a figure which shows the example of a partial expansion display of the image of FIG. It is a flowchart explaining a calibration process. It is a figure which shows the example of a display of a correction data collection screen. It is a figure explaining the installation state of a phantom.

Explanation of symbols

1 X-ray CT apparatus 31 Imaging control unit 31a Operation detection unit 31a
31b Scan condition selection unit 31c Scan execution unit 32 Image reconstruction unit 32a Calculation unit 32b Display control unit

Claims (5)

In an X-ray CT apparatus having an X-ray tube for exposing X-rays and a multi-row X-ray detector,
An imaging control unit that collects projection data by rotating the X-ray tube and the X-ray detector around a phantom that is a casing filled with a filling;
Reconstruction means for reconstructing a tomographic image based on the projection data of the phantom;
Image generating means for extracting an image of a plurality of areas set in the vicinity of the end of the phantom in the tomographic image, and generating an image for tilt confirmation by combining the images of the plurality of areas;
An X-ray CT apparatus comprising: display control means for displaying the tilt confirmation image. 2. The X-ray CT according to claim 1, wherein the image generation unit generates an image for checking the inclination by arranging images of the plurality of areas provided apart from each other so as to be adjacent to each other. apparatus. A calculation means for calculating the inclination and movement amount of the phantom;
The X-ray CT apparatus according to claim 1, wherein the display control unit further displays information indicating an inclination and a movement amount of the phantom calculated by the calculation unit. The X-ray CT apparatus according to claim 1, wherein the display control unit displays an MPR image of the phantom. In an X-ray CT apparatus having an X-ray tube for exposing X-rays and a multi-row X-ray detector,
An imaging control means for collecting projection data by relatively translating the phantom which is a casing filled with a filling material and the X-ray tube,
Reconstruction means for reconstructing a tomographic image based on the projection data of the phantom;
Calculating means for calculating the inclination and movement amount of the phantom;
An X-ray CT apparatus comprising: display control means for displaying, together with the tomographic image, information indicating the tilt and movement amount of the phantom.

Images