JP2009106653A - X-ray ct apparatus and its control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide images in a desired imaging area inexpensively and simply which have a high resolution. <P>SOLUTION: In an X-ray CT apparatus 1, an X-ray tube 22 exposes a subject P to an X-ray beam by high voltage from a high-voltage generation section 21, an X-ray detector 23 detects an X-ray detection signal from the X-ray beam penetrating the subject P, a data collection section 24 converts the X-ray detection signal to a digital signal, a preprocessing section 32 converts the digital signal to projection data by correction. A reconstruction section 34 generates tomogram data by reconstruction on the basis of the projection data. A computation section 37 computes coordinates of the central position of the imaging area on the basis of the imaging area indication data. A setting section 38 sets the amount of movement of a bed so that the central position of the imaging area is positioned at the center of rotation when scanning. A bed driving section 26 drives the bed rightward, leftward, upward, and downward to move the bed by the set amount of movement. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an X-ray CT apparatus and a control processing program therefor, and more particularly to an X-ray CT apparatus and a control processing program therefor that can increase the resolution of an image in a desired imaging region.

  In an X-ray CT apparatus, it is desired to provide a high-quality image so that a doctor, a technician, or the like (hereinafter referred to as “operator”) can easily diagnose. As one of the methods for providing a high-quality image, a method in which the entire FOV (Field of View) (shooting field of view) is set to a high resolution can be considered. However, it is very difficult in principle to make all FOVs (Field of View) high resolution in an X-ray CT apparatus. The reason can be explained as follows.

  As shown in FIG. 1, in an X-ray CT apparatus, generally, data is detected by a detector B while rotating an X-ray tube A at a required rotational speed, and then the detected data is collected as data not shown. Collect in the circuit. For example, when photographing at 1000 views (1000 sampling points) per rotation, as shown in FIG. 2, after collecting data by exposing X-rays from the X-ray tube A at the first sampling point, the X-ray tube is collected. A is rotated 1/1000 and X-rays are emitted from the X-ray tube A at the second sampling point to collect data. Then, it is rotated sequentially, and X-rays are emitted from the X-ray tube A at 1000 sampling points to collect data.

  However, even when shooting at 1000 sampling points per rotation, as shown in FIG. 3, the range of data obtained in the circumferential direction differs between the central portion and the peripheral portion of the FOV, and the collected data The sampling becomes smaller toward the central portion, but becomes rougher toward the peripheral portion. This coarsening causes a difference in resolution on the displayed image.

  That is, as shown in FIG. 4, the resolution is high in the central portion of the FOV but low in the peripheral portion of the FOV. More specifically, as shown in FIG. 5, the resolution of the FOV on the predetermined straight line K decreases while drawing a locus like a curve L from the central portion toward the peripheral portion.

  Therefore, a method of increasing the number of views per rotation (the number of sampling points) in order to achieve high resolution also in the peripheral portion of the FOV can be considered.

  However, in order to increase the number of views per rotation while maintaining the same rotation speed as before, it is necessary to improve and improve the performance of the data acquisition circuit that collects data, which is easily realized with the current technology. It is not possible.

  Even if the performance of the data acquisition circuit can be improved to a required level, if the number of views per rotation is increased while maintaining the same rotation speed as before, the X-rays counted in one view Another problem is that photons become smaller.

  As described above, in the X-ray CT apparatus, it is difficult to achieve a high resolution for all FOVs due to various factors.

  By the way, conventionally, a technique for moving a couch for placing a bed or a patient (hereinafter referred to as “subject”) not only in the vertical direction but also in the horizontal direction with respect to the rotation axis of the gantry is known. Further, as described above, the resolution is relatively higher in the central portion of the FOV than in the peripheral portion. Therefore, by moving the bed or the top / bottom / left / right direction to move the desired imaging region to the central portion of the FOV with high resolution, the operator can obtain high image quality at the imaging region desired to be observed. It is considered possible to provide an image.

As a technique related to the movement of the top board, for example, a technique described in Japanese Patent Application Laid-Open No. 2007-267783 is known.
JP 2007-267783 A

  However, in the method of moving a desired imaging region to the central portion of the FOV having high resolution by moving the bed or the top / bottom / left / right direction, any portion of the subject is placed in the central portion of the FOV having high resolution. Although it is possible to move the (region), it is not possible to set the imaging region desired to be observed to be moved to the central portion of the FOV, and the center of the FOV at which the imaging region desired to be observed becomes high resolution. There is a problem that it is difficult to move the portion with high accuracy.

  In addition, when an operator diagnoses a subject, it is rare that he wants to diagnose only a very limited local region, and the operator usually makes a diagnosis while observing a predetermined imaging region having a certain extent. Want to do. Therefore, the operator usually moves a predetermined imaging area having a certain extent to the central portion of the FOV. However, in the first place, when moving a desired imaging region, information regarding which region has what resolution and how much resolution is not displayed to the operator. For this reason, the operator cannot know where to move the subject and it is preferable to perform observation even when moving a predetermined imaging region having a certain extent to the central portion of the FOV. There has been a problem that it is not easy to move a desired imaging region to the center of the FOV.

  The present invention has been made in view of such a situation, and provides an X-ray CT apparatus and a control processing program for the X-ray CT apparatus capable of easily and high-resolution images in a desired imaging region at low cost. For the purpose.

  In order to solve the above-described problems, an X-ray CT apparatus according to the present invention detects a transmitted X-ray from a plurality of directions that is exposed from an X-ray source and passes through a subject, and an X-ray from the transmitted X-ray. Collection means for collecting detection signals, X-ray detection signals collected by the collection means are converted into projection data, image data generation means for reconstructing the converted projection data to generate image data, and image data Display means for displaying an image based on the image capturing area, data for acquiring an imaging area instruction data for instructing a predetermined imaging area, and coordinates of a center position of the predetermined imaging area based on the imaging area instruction data Center position coordinate calculation means, a bed movement amount setting means for setting the movement amount of the bed on which the subject is placed, and a bed movement amount setting means based on the calculation result by the center position coordinate calculation means. According the amount of movement of the bed was, characterized in that it comprises a bed driving means for driving the bed.

  The detection means can detect transmitted X-rays from a plurality of directions that are exposed from the X-ray source and transmitted through the subject after the bed is moved by the bed driving means.

  The bed movement amount setting means sets the movement amount of the bed based on the calculation result by the center position coordinate calculation means so that the center position of the predetermined imaging region matches the rotation center position when the scan is executed. can do.

  The image data displayed by the display means includes at least scano image data from two directions, and the photographing area instruction data acquisition means includes photographing area instruction data designated on the scano image data from two directions. Can get to.

  The image data displayed by the display unit includes at least tomographic image data, and the imaging region instruction data acquisition unit may acquire the imaging region instruction data instructed on the tomographic image data. it can.

  The image data displayed by the display means includes at least three-dimensional image data, and the imaging area instruction data acquisition means acquires the imaging area instruction data instructed on the three-dimensional image data. Can be.

  The display means can further display a resolution index on the image superimposed on an image based on image data displayed after the bed is moved by the bed driving means.

  The bed driving means can drive the bed up / down / left / right / front / back according to the movement amount of the bed set by the bed movement amount setting means.

  In order to solve the above-described problem, the control processing program of the X-ray CT apparatus of the present invention detects transmitted X-rays from a plurality of directions that are exposed from an X-ray source and transmitted through a subject, and the detected transmission X An image data generation step for collecting an X-ray detection signal from a line, converting the collected X-ray detection signal into projection data, reconstructing the converted projection data to generate image data, and an image based on the image data A display step for displaying, a shooting area instruction data acquisition step for acquiring shooting area instruction data for specifying a predetermined shooting area, and a center for calculating the coordinates of the center position of the predetermined shooting area based on the shooting area instruction data A position coordinate calculation step; a bed movement amount setting step for setting a movement amount of the bed on which the subject is placed; and a bed movement amount setting step based on the calculation result by the center position coordinate calculation means. According moving amount of the bed which is set by the processing of the flop, characterized in that to execute a couch driving step of driving the bed to the computer.

  In the X-ray CT apparatus of the present invention, transmitted X-rays emitted from an X-ray source and transmitted through a subject are detected from a plurality of directions, X-ray detection signals are collected from the transmitted X-rays, and the collected X-rays are collected. The detection signal is converted into projection data, the converted projection data is reconstructed to generate image data, an image based on the image data is displayed, shooting area instruction data indicating a predetermined shooting area is acquired, and shooting is performed. Based on the area instruction data, the coordinates of the center position of the predetermined imaging area are calculated, and the amount of movement of the bed on which the subject is placed is set based on the calculation result, and the bed is moved according to the set amount of movement of the bed. Driven.

  In the control processing program of the X-ray CT apparatus of the present invention, transmitted X-rays from a plurality of directions that are exposed from an X-ray source and transmitted through a subject are detected, and X-ray detection signals are collected from the detected transmitted X-rays. The acquired X-ray detection signal is converted into projection data, the converted projection data is reconstructed to generate image data, an image based on the image data is displayed, and an imaging area that indicates a predetermined imaging area The instruction data is acquired, the coordinates of the center position of the predetermined imaging area are calculated based on the imaging area instruction data, the amount of movement of the bed on which the subject is placed is set based on the calculation result, and the set bed The bed is driven according to the amount of movement.

  According to the present invention, an image in a desired photographing region can be easily and high-resolution inexpensively.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 6 shows an internal configuration of the X-ray CT apparatus 1 to which the present invention is applied. In the embodiment of the present invention, the present invention is applied to a multi-slice helical scan. However, the present invention is not limited to such a case. For example, various scans such as a conventional scan (single-slice scan and multi-slice scan) can be used. You may make it apply to a method. The helical scan is a scan performed by moving the subject while continuously rotating the X-ray source.

  As shown in FIG. 6, the X-ray CT apparatus 1 has a bed (not shown) on which the subject P is placed and a diagnostic opening OP for inserting the subject P and making a diagnosis, and data And a computer unit 12 that performs image reconstruction processing, image display processing, and the like based on the collected data.

  The gantry unit 11 includes a high voltage generation unit 21, an X-ray tube 22, an X-ray detector 23, a data collection unit 24, a gantry driving unit 25, and a bed driving unit 26. The X-ray tube 22, the X-ray detector 23, and the data collection unit 24 are attached to a rotating ring (not shown) that can rotate within the gantry unit 11, and the rotating ring is driven by the gantry driving unit 25. By rotating, it is possible to rotate integrally around a rotation center axis parallel to the body axis direction of the subject P inserted into the diagnostic opening OP of the gantry 11.

  The high voltage generator 21 supplies a high voltage for exposing the X-ray beam to the X-ray tube 22 based on a control signal input from the controller 31 of the computer device 12. The X-ray tube 22 acquires the high voltage supplied from the high voltage generation unit 21, and uses the acquired high voltage to cone the subject P placed on the top plate M in the FOV (imaging field of view). A (square pyramid) or fan (fan) X-ray beam is exposed from multiple directions. When the scanogram data is generated, the X-ray tube 22 applies a cone-shaped or fan-shaped X-ray beam to the subject P placed on the top plate M in the FOV by a high voltage. Exposure from one collection position (from one direction).

  Between the X-ray tube 22 in the gantry 11 and the subject P, a cone-shaped or fan-shaped X-ray beam exposed from the X-ray focal point of the X-ray tube 22 is shaped to have a required size. A collimator (not shown) for forming an X-ray beam is provided.

  The X-ray detector 23 is a device that detects X-rays transmitted through the subject P, and a plurality of X-ray detection elements are arranged in an array in two directions (slice direction and channel direction) orthogonal to each other. Detectors of about 1000 channels are arranged in an arc shape with the focal point of the X-ray tube 22 as the center. The X-ray detector 23 detects an X-ray detection signal from an X-ray beam transmitted through the subject P among the X-ray beams exposed from the X-ray tube 22 and collects the detected X-ray detection signal as data. To the unit 24.

  The data collection unit 24 converts the X-ray detection signal supplied from the X-ray detector 23 from an analog signal to a digital signal after amplification processing based on a control signal input from the control unit 31 of the computer device 12. The converted digital signal is output to the preprocessing unit 32 of the computer device 12.

  The gantry driving unit 25 appropriately drives the gantry unit 11 based on a control signal input from the control unit 31 of the computer apparatus 12. The gantry drive unit 25 can also tilt the gantry unit 11.

  Based on the control signal input from the control unit 31 of the computer device 12, the bed driving unit 26 moves the bed including the top plate M that supports the subject P vertically and horizontally as shown in FIG. Drive as appropriate. Specifically, the couch driving unit 26 drives the servo motor A-1 based on the control signal input from the control unit 31 of the computer device 12 to drive the gears by driving the servo motor A-1. B-1 is rotated, the lead screw C-1 is moved in the axial direction in conjunction with the rotation of the gear B-1, and the bed is driven up and down. Also, the bed driving unit 26 drives the servo motor A-2 based on the control signal input from the control unit 31 of the computer device 12 as shown in FIG. And the lead screw C-2 is moved in the axial direction in conjunction with the rotation of the gear B-2 to drive the bed left and right.

  On the other hand, the computer device 12 includes a computer device body 27, an input unit 28, and a display unit 29. The computer apparatus main body 27 further includes a control unit 31, a preprocessing unit 32, a storage unit 33, a reconstruction unit 34, a scano image data generation unit 35, an input data acquisition unit 36, a calculation unit 37, and a setting unit 38.

  The control unit 31 includes a CPU (Central Processing Unit) or MPU (Micro Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and generates various control signals and supplies them to each unit. Thus, the driving of the X-ray CT apparatus 1 is comprehensively controlled.

  Under the control of the control unit 31, the preprocessing unit 32 performs a correction process on the digital signal input from the data collection unit 24 of the gantry unit 11 to convert it into projection data, and the converted projection data is stored in the storage unit 33. Supply.

  The storage unit 33 acquires the projection data supplied from the preprocessing unit 32, sequentially stores the acquired projection data, and supplies the acquired projection data to each unit of the computer apparatus 12 as necessary. The storage unit 33 acquires slice tomographic image data, arbitrary slice tomographic image data, three-dimensional image data, and the like supplied from the reconstruction unit 34, and acquires the acquired slice tomographic image data and arbitrary slices. Tomographic image data and three-dimensional image data are stored.

  The storage unit 33 acquires the scano image data supplied from the scano image data generation unit 35, stores the acquired scano image data, and supplies the acquired scano image data to each unit of the computer apparatus 12 as necessary. The storage unit 33 stores various data necessary for various processes and supplies the data to each unit of the computer device 12 as necessary.

  The reconstruction unit 34 reads the projection data stored in the storage unit 33 according to the control of the control unit 31, and performs reconstruction processing using the cone beam reconstruction method or the fan beam reconstruction method based on the read projection data. To generate slice tomographic image data and supply the generated slice tomographic image data to the display unit 29 and the storage unit 33.

  Further, the reconstruction unit 34 reads the tomographic image data of a plurality of slices stored in the storage unit 33 and converts the read tomographic image data of the plurality of slices into volume data under the control of the control unit 31. The reconstruction unit 34 generates tomographic image data or 3D image data of an arbitrary cross section based on the converted volume data, and generates the generated tomographic image data or 3D image data of an arbitrary cross section. The data is supplied to the display unit 29 and the storage unit 33.

  The scano image data generation unit 35 reads the projection data stored in the storage unit 33, arranges the read projection data according to the collection position, generates scano image data, and generates the generated scano image data. The data is supplied to the display unit 29 and the storage unit 33.

  The input data acquisition unit 36 acquires various input data input by the operator operating the input unit 28, and supplies the acquired various input data to the storage unit 33. The input data acquisition unit 36 supplies to the control unit 31 and the calculation unit 37 imaging region instruction data that indicates an imaging region desired by the operator among the acquired input data.

  The calculation unit 37 acquires the imaging region instruction data supplied from the input data acquisition unit 36 according to the control of the control unit 31, and based on the acquired imaging region instruction data, the center position of the imaging region instructed by the operator The coordinates of the center position of the photographing region is calculated, and the photographing region center position coordinate data, which is data relating to the coordinates of the calculated center position of the photographing region, is supplied to the setting unit 38.

  The setting unit 38 acquires the imaging region center position coordinate data supplied from the calculation unit 37 according to the control of the control unit 31, and the imaging region center position scans based on the acquired imaging region center position coordinate data. Set the amount of movement of the couch so that it will be the rotation center position when you do. The setting unit 38 supplies bed movement amount setting data, which is data regarding the set movement amount of the bed, to the control unit 31 and the storage unit 33.

  The input unit 28 is connected to the computer apparatus main body 27 via an electric cable, and a display panel (not shown) for inputting various instructions of the operator on the operation panel, a trackball, various operation switches, various types It has input devices such as buttons, a mouse, and a keyboard, and is used by the operator to input the width of the X-ray exposure region in the slice direction, the scan range, and the like.

  The display unit 29 is connected to the computer apparatus body 27 via a cable, and is provided with an LCD (Liquid Crystal Display) (not shown) and a CRT (Cathode Ray Tube) (not shown). Various image data supplied from the configuration unit 34 and the storage unit 33 are acquired, and an image based on the acquired image data is displayed on an LCD or CRT (not shown).

  With reference to the flowchart of FIG. 8, the bed movement process in the X-ray CT apparatus 1 of FIG. 6 will be described.

  In step S <b> 1, the X-ray CT apparatus 1 collects scanograms from two directions under the control of the control unit 31. That is, the gantry driving unit 25 rotates the gantry unit 11 based on the gantry driving control signal supplied from the control unit 31 and stops it at the first collection position (position at which the tube position becomes 0 degree).

  The high voltage generation unit 21 supplies a high voltage for exposing the X-ray beam to the X-ray tube 22 based on the high voltage generation control signal input from the control unit 31. The X-ray tube 22 acquires the high voltage supplied from the high voltage generation unit 21, and the acquired high voltage causes the subject P placed on the top plate M in the FOV to have a cone shape or a fan shape. X-ray beam is exposed from the first acquisition position.

  The X-ray detector 23 detects an X-ray detection signal from an X-ray beam transmitted through the subject P among the X-ray beams exposed from the X-ray tube 22 and collects the detected X-ray detection signal as data. To the unit 24. The data acquisition unit 24 converts the X-ray detection signal supplied from the X-ray detector 23 from the analog signal to the digital signal after amplification processing based on the data acquisition control signal input from the control unit 31 and after the conversion. Are output to the preprocessing unit 32 of the computer device 12.

  Under the control of the control unit 31, the preprocessing unit 32 of the computer device 12 performs correction processing on the digital signal input from the data collection unit 24 of the gantry unit 11 to convert it into projection data, and converts the converted projection data. The data is supplied to the storage unit 33.

  The scano image data generation unit 35 reads the projection data stored in the storage unit 33, arranges the read projection data in accordance with the collection position, and sets the first scano image data (that is, tube position 0 degree). And the first scan image data thus generated is supplied to the storage unit 33 and the display unit 29.

  The storage unit 33 acquires the first scano image data supplied from the scano image data generation unit 35 and stores the acquired first scano image data.

  The display unit 29 acquires the first scano image data supplied from the scano image data generation unit 35, and the first scano image based on the acquired first scano image data is shown in FIG. 9A. Display on an LCD or CRT (not shown). Note that the vertical axis in FIG. 9A is the Z axis and indicates the body axis direction of the subject P, the horizontal axis is the X axis, and the axial direction from the right side surface to the left side surface of the subject P is shown. Show.

  Next, the gantry driving unit 25 rotates the gantry unit 11 by 90 degrees from the first collection position on the basis of the gantry drive control signal supplied from the control unit 31 to the second collection position (tube position 90 degrees). Stop at position.

  The high voltage generation unit 21 supplies a high voltage for exposing the X-ray beam to the X-ray tube 22 based on the high voltage generation control signal input from the control unit 31. The X-ray tube 22 acquires the high voltage supplied from the high voltage generation unit 21, and the acquired high voltage causes the subject P placed on the top plate M in the FOV to have a cone shape or a fan shape. X-ray beam is exposed from the second acquisition position.

  The X-ray detector 23 detects an X-ray detection signal from an X-ray beam transmitted through the subject P among the X-ray beams exposed from the X-ray tube 22 and collects the detected X-ray detection signal as data. To the unit 24. The data acquisition unit 24 converts the X-ray detection signal supplied from the X-ray detector 23 from the analog signal to the digital signal after amplification processing based on the data acquisition control signal input from the control unit 31 and after the conversion. Are output to the preprocessing unit 32 of the computer device 12.

  Under the control of the control unit 31, the preprocessing unit 32 of the computer device 12 performs correction processing on the digital signal input from the data collection unit 24 of the gantry unit 11 to convert it into projection data, and converts the converted projection data. The data is supplied to the storage unit 33.

  The scano image data generation unit 35 reads the projection data stored in the storage unit 33, arranges the read projection data according to the collection position, and generates second scano image data (that is, tube position 90 degrees). And the generated second scano image data is supplied to the storage unit 33 and the display unit 29.

  The storage unit 33 acquires the second scano image data supplied from the scano image data generation unit 35, and stores the acquired second scano image data.

  The display unit 29 acquires the second scano image data supplied from the scano image data generation unit 35, and the second scano image based on the acquired second scano image data is shown in FIG. 9B. Display on an LCD or CRT (not shown). Note that the vertical axis in FIG. 9B is the Z axis as in FIG. 9A, indicating the body axis direction of the subject P, the horizontal axis is the Y axis, and from the back of the subject P. The axial direction to the front is shown.

  In step S2, the X-ray CT apparatus 1 sets the amount of movement of the bed and the scan range. Specifically, the following processing is performed.

  First, the operator operates the input unit 28 with reference to the two-way scan images (first scan image and second scan image) shown in FIGS. An imaging region (hereinafter referred to as “high-resolution imaging region”) for which imaging is desired is designated. Specifically, for example, when the heart is designated as the high-resolution imaging region, the operator designates the ranges of RZ and RX with respect to the Z axis and the X axis, respectively, using the first scan image of FIG. 9A. At the same time, ranges of RZ and RY are designated for the Z axis and the Y axis, respectively, using the second scanogram of FIG. 9B. Note that the RZ range specified using the first scano image in FIG. 9A matches the RZ range specified using the second scano image in FIG. 9B. .

  The input data acquisition unit 36 acquires imaging region instruction data that indicates a high-resolution imaging region input by the operator operating the input unit 28, and the acquired imaging region instruction data is used as a control unit 31 and a calculation unit 37. To supply.

The calculation unit 37 acquires the shooting area instruction data supplied from the input data acquisition unit 36, and based on the acquired shooting area instruction data, as shown in FIG. The coordinates (Q ₁ X, Q ₁ Y) on the XY plane of the imaging area center position Q ₁ that is the center position of the resolution imaging area are calculated, and the data relating to the calculated coordinates of the imaging area center position Q ₁ is high. The resolution imaging region center position coordinate data is supplied to the setting unit 38. In the case of the example in FIG. 10A, the X-axis coordinate Q ₁ X and the Y-axis coordinate Q ₁ Y of the imaging region center position Q ₁ are positive values.

  In the example of FIG. 10A, the position of the origin O (0, 0) on the XY plane is the rotation center position when the scan is executed, and the bed on which the subject P is placed is placed. By driving, it is possible to move the desired high-resolution imaging region so as to match the rotation center position when the scan is executed.

The setting unit 38 acquires the imaging region center position coordinate data supplied from the calculation unit 37, and based on the acquired imaging region center position coordinate data, as illustrated in FIG. by translating relative to the axis, to match the rotation center position when the photographing area center position Q ₁ is to perform a scan, it sets the movement amount of the bed. Specifically, in the example of FIG. 10A, the origin O (0, 0) on the XY plane whose coordinates (Q ₁ X, Q ₁ Y) of the imaging region center position Q ₁ are the rotation center positions. As the amount of movement of the bed, −Q ₁ X is set in the X-axis direction and −Q ₁ Y is set in the Y-axis direction so as to match the position. The setting unit 38 supplies bed movement amount setting data, which is data regarding the set movement amount of the bed, to the control unit 31 and the storage unit 33.

  Next, the operator operates the input unit 28 to specify a scan range in which the scan is executed. When designating the scan range, the operator designates the scan range so that the already designated high-resolution imaging region is included.

  The input data acquisition unit 36 acquires scan range instruction data indicating the scan range input by the operator operating the input unit 28, and supplies the acquired scan range data to the control unit 31.

  The control unit 31 acquires the scan range instruction data supplied from the input data acquisition unit 36, sets the scan range based on the acquired scan range instruction data, and sets the scan range setting data related to the set scan range. The data is supplied to the storage unit 33. The storage unit 33 acquires the scan range setting data supplied from the control unit 31, and stores the acquired scan range setting data.

In step S3, X-ray CT apparatus 1 moves the bed to fit the rotation center position when the center position of the desired high-resolution imaging area capturing area center position Q ₁ is to perform the scan.

  That is, the control unit 31 acquires the couch movement amount setting data supplied from the setting unit 38, and drives the couch in the X axis direction and the Y axis direction based on the acquired couch movement amount setting data. A drive control signal is generated. The control unit 31 reads data related to the scan start position included in the scan range setting data stored in the storage unit 33, and moves the bed to the scan start position based on the read data related to the scan start position. A Z-axis direction couch driving control signal for driving in the Z-axis direction (body axis direction) is generated. The control unit 31 supplies the generated XY axis direction couch driving control signal and Z axis direction couch driving control signal to the couch driving unit 26.

Based on the XY axis direction couch driving control signal and the Z axis direction couch driving control signal supplied from the control unit 31, the couch driving unit 26, as shown in FIG. 11, at the center position of the desired high-resolution imaging region. to match the rotation center position when in photographing area center position Q ₁ is to perform a scan, by driving the bed containing the top plate M for supporting the subject P, respectively, in the X-axis direction -Q 1 _X, It moves by -Q ₁ Y in the Y-axis direction and moves by a predetermined distance (distance for moving to the scan start position) in the Z-axis direction.

  That is, the bed is driven not only in the X-axis direction and the Y-axis direction but also in the Z-axis direction and moved by a predetermined distance.

  As a result, the amount of movement of the bed is set so that the high-resolution imaging area, which is an imaging area for which shooting is desired with high resolution, matches the rotation center position when scanning is performed, and the bed is set according to the set amount of movement of the bed. Can be moved.

  In step S4, the X-ray CT apparatus 1 performs a main scan. That is, the control unit 31 reads the scan range setting data stored in the storage unit 33 and executes a scan based on the read scan range setting data.

  The high voltage generator 21 supplies a high voltage for exposing the X-ray beam to the X-ray tube 22 based on the high voltage control signal input from the controller 31. The X-ray tube 22 acquires the high voltage supplied from the high voltage generator 21, and the acquired high voltage causes the subject P placed on the top board M (bed) in the FOV to have a cone shape. Alternatively, a fan-shaped X-ray beam is exposed from multiple directions.

  The X-ray detector 23 detects an X-ray detection signal from an X-ray beam transmitted through the subject P among the X-ray beams exposed from the X-ray tube 22 and collects the detected X-ray detection signal as data. To the unit 24. The data acquisition unit 24 converts the X-ray detection signal supplied from the X-ray detector 23 from the analog signal to the digital signal after amplification processing based on the data acquisition control signal input from the control unit 31 and after the conversion. Are output to the preprocessing unit 32 of the computer device 12.

  Under the control of the control unit 31, the preprocessing unit 32 performs correction processing on the digital signal input from the data collection unit 24 of the gantry unit 11 to convert it into projection data, and stores the converted projection data in the storage unit 33. Supply. The storage unit 33 acquires the projection data supplied from the preprocessing unit 32 and sequentially stores the acquired projection data.

  In step S5, the reconstruction unit 34 reads the projection data stored in the storage unit 33 according to the control of the control unit 31, and the cone beam reconstruction method or the fan beam reconstruction method based on the read projection data. Then, the tomographic image data of the slice is generated by performing the reconstruction processing in step S, and the generated tomographic image data of the slice is supplied to the display unit 29 and the storage unit 33. The storage unit 33 acquires the slice tomographic image data supplied from the reconstruction unit 34 and stores the acquired slice tomographic image data.

  Further, the reconstruction unit 34 reads the tomographic image data of a plurality of slices stored in the storage unit 33 and converts the read tomographic image data of the plurality of slices into volume data under the control of the control unit 31. The reconstruction unit 34 generates tomographic image data or 3D image data of an arbitrary cross section based on the converted volume data, and generates the generated tomographic image data or 3D image data of an arbitrary cross section. The data is supplied to the display unit 29 and the storage unit 33.

  The storage unit 33 acquires tomographic image data or three-dimensional image data of any section supplied from the reconstruction unit 34, and stores the acquired tomographic image data or three-dimensional image data of any section. To do.

  The display unit 29 acquires tomographic image data of a slice supplied from the reconstruction unit 34, tomographic image data of an arbitrary cross section, three-dimensional image data, and the like, and a tomographic image based on the acquired slice tomographic image data A tomographic image based on tomographic image data of an arbitrary cross section, a three-dimensional image based on three-dimensional image data, and the like are displayed on an LCD or CRT (not shown).

  In the embodiment of the present invention, the coordinates of the center position of a desired shooting area are calculated using a scan image in two directions, and shooting with high resolution is desired based on the coordinates of the center position of the calculated shooting area. Since the bed is moved so that the high-resolution imaging area, which is the imaging area, matches the rotation center position when scanning is performed, images in the desired imaging area can be inexpensively repeated without repeating the practice scan. In addition, high resolution can be easily achieved.

  Note that the two collection positions for collecting the scanograms in the two directions are not limited to the tube position of 0 degrees and the tube position of 90 degrees, and may be different collection positions.

  By the way, in the bed movement process described with reference to the flowchart of FIG. 8, the amount of movement of the bed so that the desired imaging region matches the rotation center position when the scan is executed, using scanograms from two directions. However, before the main scan, the pre-scan, which is a scan for preparation, is first executed, and the desired shooting area is scanned using the image displayed by the executed pre-scan. You may make it set the movement amount of a bed so that it may correspond to the rotation center position at the time of execution. Hereinafter, the bed movement process using the image by the pre-scan will be described.

  With reference to the flowchart of FIG. 12, another bed movement process in the X-ray CT apparatus 1 of FIG. 6 will be described. Note that the processing in step S17 and step S18 in FIG. 12 is the same as the processing in step S4 and step 5 in FIG.

  In step S11, the X-ray CT apparatus 1 collects a scano image. That is, the gantry driving unit 25 rotates the gantry unit 11 based on the gantry driving control signal supplied from the control unit 31 and stops it at a predetermined collection position.

  The high voltage generation unit 21 supplies a high voltage for exposing the X-ray beam to the X-ray tube 22 based on the high voltage generation control signal input from the control unit 31. The X-ray tube 22 acquires the high voltage supplied from the high voltage generator 21, and the acquired high voltage causes the subject P placed on the top board M (bed) in the FOV to have a cone shape. Alternatively, a fan-shaped X-ray beam is exposed from a predetermined collection position.

  The X-ray detector 23 detects an X-ray detection signal from an X-ray beam transmitted through the subject P among the X-ray beams exposed from the X-ray tube 22 and collects the detected X-ray detection signal as data. To the unit 24. The data acquisition unit 24 converts the X-ray detection signal supplied from the X-ray detector 23 from the analog signal to the digital signal after amplification processing based on the data acquisition control signal input from the control unit 31 and after the conversion. Are output to the preprocessing unit 32 of the computer device 12.

  Under the control of the control unit 31, the preprocessing unit 32 of the computer device 12 performs correction processing on the digital signal input from the data collection unit 24 of the gantry unit 11 to convert it into projection data, and converts the converted projection data. The data is supplied to the storage unit 33.

  The scanogram data generation unit 35 reads the projection data stored in the storage unit 33, arranges the read projection data according to the collection position, generates scano image data, and generates the scano image data. Is supplied to the storage unit 33 and the display unit 29.

  The storage unit 33 acquires the scano image data supplied from the scano image data generation unit 35 and stores the acquired scano image data.

  The display unit 29 acquires the scano image data supplied from the scano image data generation unit 35, and displays a scano image based on the acquired scano image data on an LCD or CRT (not shown).

  Thereafter, the operator operates the input unit 28 to designate a scan range for executing the scan.

  In step S <b> 12, the input data acquisition unit 36 acquires scan range instruction data indicating the scan range input by the operator operating the input unit 28, and supplies the acquired scan range data to the control unit 31. .

  The control unit 31 acquires the scan range instruction data supplied from the input data acquisition unit 36, sets the scan range based on the acquired scan range instruction data, and sets the scan range setting data related to the set scan range. The data is supplied to the storage unit 33. The storage unit 33 acquires the scan range setting data supplied from the control unit 31, and stores the acquired scan range setting data.

  In step S13, the X-ray CT apparatus 1 performs pre-scanning. That is, the control unit 31 reads the scan range setting data stored in the storage unit 33, and executes pre-scan based on the read scan range setting data.

  The high voltage generator 21 supplies a high voltage for exposing the X-ray beam to the X-ray tube 22 based on the high voltage control signal input from the controller 31. The X-ray tube 22 acquires the high voltage supplied from the high voltage generator 21, and the acquired high voltage causes the subject P placed on the top board M (bed) in the FOV to have a cone shape. Alternatively, a fan-shaped X-ray beam is exposed from multiple directions.

  The X-ray detector 23 detects an X-ray detection signal from an X-ray beam transmitted through the subject P among the X-ray beams exposed from the X-ray tube 22 and collects the detected X-ray detection signal as data. To the unit 24. The data acquisition unit 24 converts the X-ray detection signal supplied from the X-ray detector 23 from the analog signal to the digital signal after amplification processing based on the data acquisition control signal input from the control unit 31 and after the conversion. Are output to the preprocessing unit 32 of the computer device 12.

  Under the control of the control unit 31, the preprocessing unit 32 performs a correction process on the digital signal input from the data collection unit 24 of the gantry unit 11 to convert it into projection data, and the converted projection data is stored in the storage unit 33. Supply. The storage unit 33 acquires the projection data supplied from the preprocessing unit 32 and sequentially stores the acquired projection data.

  In step S14, the reconstruction unit 34 reads the projection data stored in the storage unit 33 according to the control of the control unit 31, and the cone beam reconstruction method or the cone beam reconstruction method based on the read projection data. Then, the tomographic image data of the slice is generated by performing the reconstruction processing in step S, and the generated tomographic image data of the slice is supplied to the display unit 29 and the storage unit 33. The storage unit 33 acquires the slice tomographic image data supplied from the reconstruction unit 34 and stores the acquired slice tomographic image data.

  The display unit 29 acquires the tomographic image data of the slice supplied from the reconstruction unit 34, and displays the tomographic image based on the acquired tomographic image data of the slice on an LCD or CRT (not shown) as shown in FIG. indicate.

  In step S15, the X-ray CT apparatus 1 sets the amount of movement of the bed and the scan range. Specifically, the following processing is performed.

  First, the operator designates a high-resolution imaging region in which high-resolution imaging is desired by operating the input unit 28 while referring to a tomographic image as shown in FIG. Specifically, in the case of the example of FIG. 13, when the area a, the area b, and the area c are high-resolution imaging areas in the image displayed on the display screen, as shown in FIG. By operating the input unit 28, a predetermined area including the area a, the area b, and the area c in FIG. 13 is designated as a high resolution imaging area using the high resolution imaging area designation icon 41.

  The input data acquisition unit 36 acquires imaging region instruction data that indicates a high-resolution imaging region input by the operator operating the input unit 28, and the acquired imaging region instruction data is used as a control unit 31 and a calculation unit 37. To supply.

The calculation unit 37 acquires the imaging area instruction data supplied from the input data acquisition unit 36, and based on the acquired imaging area instruction data, the imaging area center that is the center position of the high-resolution imaging area instructed by the operator The coordinates (−Q ₂ X, −Q ₂ Y) of the position Q _{2 on} the XY plane are calculated, and shooting area center position coordinate data, which is data relating to the coordinates of the calculated shooting area center position Q ₂ , is set. To supply. In the case of the example in FIG. 14, the X-axis coordinate −Q ₂ X and the Y-axis coordinate −Q ₂ Y of the imaging region center position Q ₂ are negative values.

The setting unit 38 acquires the imaging region center position coordinate data supplied from the calculation unit 37, and moves in parallel with respect to the X axis and the Y axis based on the acquired imaging region center position coordinate data. position Q ₂ sets the rotation center position movement amount of the bed to fit in (the origin O (0,0)) when performing a scan. Specifically, in the example of FIG. 14, the position of the origin O (0, 0) on the XY plane where the coordinates (−Q ₂ X, −Q ₂ Y) of the imaging region center position Q ₂ is the rotation center position. So that the amount of movement of the bed is + Q ₂ X in the X-axis direction and + Q ₂ Y is set in the Y-axis direction. The setting unit 38 supplies bed movement amount setting data, which is data regarding the set movement amount of the bed, to the control unit 31 and the storage unit 33.

In step S16, X-ray CT apparatus 1 moves the bed to fit the rotation center position when the center position of the desired high-resolution imaging area capturing area center position Q ₂ executes a scan.

  That is, the control unit 31 acquires the couch movement amount setting data supplied from the setting unit 38, and drives the couch in the X axis direction and the Y axis direction based on the acquired couch movement amount setting data. A drive control signal is generated. The control unit 31 reads data related to the scan start position included in the scan range setting data stored in the storage unit 33, and moves the bed to the scan start position based on the read data related to the scan start position. A Z-axis direction couch driving control signal for driving in the Z-axis direction (body axis direction) is generated. The control unit 31 supplies the generated XY axis direction couch driving control signal and Z axis direction couch driving control signal to the couch driving unit 26.

Bed driving unit 26 based on the XY-axis direction bed driving control signal and the Z-axis direction bed drive control signal supplied from the control unit 31, the imaging region center position Q ₂ is the center position of the desired high resolution imaging region The bed including the top plate M that supports the subject P is driven so as to match the rotation center position at the time of executing the scan, and moves + Q ₂ X in the X-axis direction and + Q ₂ Y in the Y-axis direction, respectively. .

  As a result, the amount of movement of the bed is set so that the high-resolution imaging area, which is an imaging area for which shooting is desired with high resolution, matches the rotation center position when scanning is performed, and the bed is set according to the set amount of movement of the bed. Can be moved.

  Thereafter, the main scan is executed in the state after the bed is moved by the processing of step S17 and step S18 in FIG. 12, and the image is reconstructed and displayed.

  In the embodiment of the present invention, the coordinates of the center position of a desired high-resolution imaging area are calculated using the tomographic image generated and displayed by the pre-scan, and based on the calculated coordinates of the center position of the high-resolution imaging area. Because the bed is moved so that the high-resolution imaging area, which is the imaging area where imaging is desired with high resolution, matches the rotation center position when performing the scan, without repeating the practice scan many times, An image in a desired photographing region can be easily and high resolution inexpensively.

  By the way, normally, in the X-ray CT apparatus 1, as shown in FIG. 15, when an image is taken with a 512 × 512 matrix and an FOV diameter of 400 mm, the size of one pixel of the image is about 0.8 mm. Although it is × 0.8 mm, the limit value of the spatial resolution of the X-ray CT apparatus 1 is usually about 0.5 mm. Therefore, by performing further enlargement reconstruction processing on the image generated by scanning, it is possible to draw out the performance of the X-ray CT apparatus 1 to the limit and display the image with higher resolution. .

  Therefore, in the case where the main scan is executed after the bed movement amount is set so that the high-resolution imaging region matches the rotation center position by the bed movement processing, and the image generated by the executed main scan is displayed, Further, by performing enlargement reconstruction processing, it is possible to display an image in a high-resolution imaging area captured at a high resolution with a higher resolution.

  However, generally, when performing the enlargement reconstruction process, the operator cannot know which part of the image displayed on the display screen is displayed with what resolution. That is, it is impossible to know which part of the image displayed on the display screen has a room for improving the resolution. For this reason, it is difficult for the operator to draw out the performance of the X-ray CT apparatus 1 to the limit, perform the enlargement reconstruction process, and display the image with the resolution increased to the limit.

  Therefore, when the enlargement reconstruction process is performed on the image displayed on the display unit 29 after the bed is moved, the resolution height is superimposed on the image and displayed. As a result, it is possible to display an image in a high-resolution imaging region captured with a high resolution with a higher resolution. Hereinafter, the enlargement reconstruction / image display process will be described.

  With reference to the flowchart of FIG. 16, the enlargement reconstruction / image display process in the X-ray CT apparatus 1 of FIG. 6 will be described. The enlargement reconstruction / image display process is started after the bed movement process.

  In step S21, the X-ray CT apparatus 1 displays a resolution index. Specifically, for example, as shown in FIG. 17, an index of resolution on the image displayed after the bed movement process is displayed as a coordinate curve. In the case of the example of FIG. 17, the resolution on the predetermined straight line K of the high-resolution imaging region has a locus like a curve L as it goes from the central part to the peripheral part (from regions A, B, and C). Decline while drawing.

  Further, for example, as shown in FIG. 18, an index corresponding to the resolution height (an index corresponding to the area A, the area B, and the area C) may be superimposed and displayed. For example, color display may be performed by changing the color tone according to the regions A, B, and C, and characters, icons, and the like may be displayed as indices.

  Thereby, the operator can know which part of the image displayed on the display screen is displayed with what resolution, and can know how much room to increase the resolution.

  Next, the operator operates the input unit 28 while referring to the images as shown in FIG. 17 and FIG. 18 to designate the range to be enlarged and reconstructed, and enlarge and reconstruct the X-ray CT apparatus 1. Let the range be set.

  In step S22, the X-ray CT apparatus 1 sets a range for enlargement reconstruction.

  That is, the input data acquisition unit 36 acquires the enlarged reconstruction range instruction data that indicates the range to be enlarged and reconstructed that is input by the operator operating the input unit 28, and uses the obtained enlarged reconstruction range instruction data. It supplies to the control part 31.

  The control unit 31 acquires the enlarged reconstruction range instruction data supplied from the input data acquisition unit 36, sets the range to be enlarged and reconstructed based on the acquired enlarged reconstruction range instruction data, and is set The enlarged reconstruction range setting data, which is the enlarged reconstruction range setting data, is supplied to the storage unit 33 and the reconstruction unit 34.

  The storage unit 33 acquires the enlarged reconstruction range setting data supplied from the control unit 31, and stores the acquired enlarged reconstruction range setting data.

  In step S23, the X-ray CT apparatus 1 executes enlargement reconstruction and image display.

  That is, the reconstruction unit 34 acquires the expanded reconstruction range setting data supplied from the control unit 31, and based on the acquired expanded reconstruction range setting data, the expanded reconstruction range stored in the storage unit 33. The tomographic image data of the slice corresponding to is read out, and enlarged reconstruction image data is generated by performing enlargement reconstruction based on the read slice tomographic image data, and the generated enlarged reconstruction image data is displayed on the display unit 29 and the storage unit 33.

  The storage unit 33 acquires the enlarged reconstructed image data supplied from the reconstructing unit 34, and stores the acquired enlarged reconstructed image data. The display unit 29 acquires the enlarged reconstructed image data supplied from the reconstructing unit 34, and displays an enlarged reconstructed image based on the acquired enlarged reconstructed image data on an LCD or CRT (not shown).

  19A and 19B show display examples of tomographic images and enlarged reconstructed images displayed on the display unit 29. FIG.

  In the case of the example in FIG. 19, the tomographic image in FIG. 19A was displayed before the enlargement reconstruction process, but the enlarged reconstruction image in FIG. 19B is displayed by performing the enlargement reconstruction process. Is done.

  As a result, it is possible to display an image in a high-resolution imaging region captured with a high resolution with a higher resolution. Therefore, an image in a desired photographing region can be inexpensively and easily and have a high resolution.

  By the way, when the operator operates the input unit 28 to input a high-resolution imaging region, the operator can continuously cross sections perpendicular to the body axis direction of the subject P as shown in FIG. The part (imaging region) to be formed is not necessarily specified. For example, as shown in FIG. 21, a cross section perpendicular to the axial direction having a predetermined inclination with respect to the body axis direction of the subject P is continuous. It is also conceivable to specify a region (imaging region) formed by doing so.

  Therefore, in the image display process of step S14 in FIG. 12, a three-dimensional image to which depth information is added is displayed using the MIP (Maximum Intensity Projection) display method, the volume rendering method, or the like. The high-resolution imaging area may be designated three-dimensionally while referring to a three-dimensional image.

In such a case, in the process of step S15 in FIG. 12, the calculation unit 37, based on the acquired imaging area instruction data, the imaging area center position Q ₂ that is the center position of the high-resolution imaging area instructed by the operator. The coordinates in the XYZ space (−Q ₂ X, −Q ₂ Y, −Q ₂ Z) are calculated. Setting unit 38 based on the imaging region center position coordinate data, by translating with respect to the X-axis and Y-axis, the rotational center position when the photographing area center position Q ₂ executes a scan (the origin O (0,0 )), The amount of movement of the bed in the X-axis direction and Y-axis direction is set.

Specifically, the coordinates (−Q ₂ X, −Q ₂ Y, −Q ₂ Z) of the imaging region center position Q ₂ match the position of the origin O (0, 0) on the XY plane that is the rotation center position. Thus, the movement amount of the bed is set to + Q ₂ X in the X-axis direction and + Q ₂ Y in the Y-axis direction.

Further, setting unit 38, based on data relating to the coordinates on the Z axis of the imaging region center position Q ₂ to which is included in the imaging region center position coordinate data, as the high resolution imaging area becomes a suitable position within the scan range The amount of movement of the bed in the Z-axis direction is set. Specifically, + Q ₂ Z is set in the Z-axis direction as the amount of movement of the bed so that the high-resolution imaging region is in a suitable position within the scan range.

  The setting unit 38 supplies bed movement amount setting data, which is data regarding the set movement amount of the bed, to the control unit 31 and the storage unit 33. The storage unit 33 acquires the bed movement amount setting data supplied from the setting unit 38 and stores the acquired bed movement amount setting data.

  The control unit 31 generates an XYZ-axis direction bed drive control signal for driving the bed in the X-axis direction, the Y-axis direction, and the Z-axis direction based on the bed movement amount setting data supplied from the setting unit 38. The control unit 31 supplies the generated XYZ axial direction bed driving control signal to the bed driving unit 26.

In the process of step S16 in FIG. 12, the couch driving unit 26, based on the XYZ-axis couch driving control signal supplied from the control unit 31, as shown in FIG. 11, the center position of the desired high-resolution imaging region. is as photographing area center position Q ₂ is aligned to the rotational center position when performing a scan at, by driving the bed containing the top plate M for supporting the subject P, respectively, in the X-axis direction Q _{2 X,} Q ₂ Y moves in the Y-axis direction and Q ₂ Z moves in the Z-axis direction.

  Thereafter, the main scan is executed in the state after the bed is moved by the processing of step S17 and step S18 in FIG. 12, and the image is reconstructed and displayed.

  Thus, the amount of movement of the bed is set so that the high-resolution imaging area, which is the area to be imaged with high resolution, matches the rotation center position when performing the scan, and the bed is moved according to the set amount of movement of the bed. In addition to this, it is possible to perform a cylindrical high-definition scan in a direction that is not parallel to the rotation axis. Therefore, an image in a desired photographing region can be inexpensively and easily and have a high resolution.

  When a region (imaging region) formed by a continuous section perpendicular to the axial direction having a predetermined inclination with respect to the body axis direction of the subject P is designated, a higher-definition scan is performed. The gantry 11 may be driven and tilted by a predetermined inclination so that it can be performed.

  In the X-ray CT apparatus 1 shown in the embodiment of the present invention, an operator designates a high-resolution imaging region desired to be imaged with high resolution while referring to a scano image from two directions or an image by pre-scanning. However, the present invention is not limited to such a case. For example, by specifying a predetermined position that the operator wants to match the rotation center position when executing the scan, a predetermined height based on the predetermined position is specified. A resolution imaging region may be set, and the bed may be moved so that the predetermined position matches the rotation center position when the scan is executed.

  At that time, the set predetermined high-resolution imaging region may be marked and displayed on the screen, and the operator may perform fine adjustment while observing the displayed predetermined high-resolution imaging region.

  Furthermore, in the X-ray CT apparatus 1 shown in the embodiment of the present invention, the X-ray CT apparatus 1 is applied to a pair of the X-ray tube 22 and the X-ray detector 23. You may make it apply to the above X-ray tube 22 and the X-ray detector 23. FIG.

  In the X-ray CT apparatus 1 shown in the embodiment of the present invention, the bed movement process of FIG. 8 and the bed movement process of FIG. 12 are performed separately, but the bed movement process of FIG. 8 is performed. Then, the bed movement process of FIG. 12 may be further performed. Thereby, an image in a desired photographing region can be inexpensively and easily and have a high resolution.

  Further, in the X-ray CT apparatus 1 shown in the embodiment of the present invention, the present invention is applied to a case where a slice tomographic image is reconstructed and displayed. You may make it apply when reconstructing and displaying a three-dimensional image.

  In the embodiment of the present invention, the steps of the flowchart show examples of processing performed in time series according to the described order. However, the steps in the flowchart are not necessarily processed in time series, but in parallel or individually. The process to be executed is also included.

Explanatory drawing explaining the sampling method of X-ray CT apparatus. Explanatory drawing explaining the sampling method of X-ray CT apparatus. Explanatory drawing explaining the difference of the sampling of the data collected in the center part and peripheral part of FOV. Explanatory drawing explaining the difference of the resolution in the center part and peripheral part of FOV. Explanatory drawing explaining the difference of the resolution in the center part and peripheral part of FOV. The block diagram which shows the internal structure of the X-ray CT apparatus to which this invention is applied. [A], [B], and [C] are explanatory views for explaining a method of driving the bed of FIG. The flowchart explaining the bed movement process in the X-ray CT apparatus of FIG. [A] and [B] are diagrams showing display examples of scanograms from two directions displayed on the display unit of FIG. [A] and [B] are explanatory views for explaining a calculation method for calculating the center position of the high-resolution imaging region. Explanatory drawing explaining the bed movement method performed by the bed movement process in step S3 of FIG. The flowchart explaining the other bed movement process in the X-ray CT apparatus of FIG. The figure which shows the example of a display of the tomographic image of the slice displayed on the display part of FIG. Explanatory drawing explaining the designation | designated method which designates a high-resolution imaging | photography area | region. Explanatory drawing explaining the limit value of the resolution which X-ray CT apparatus has. 7 is a flowchart for explaining enlargement reconstruction / image display processing in the X-ray CT apparatus of FIG. 6. The figure which shows the example of a display of the tomographic image of the slice displayed on the display part of FIG. The figure which shows the example of a display of the tomographic image of another slice displayed on the display part of FIG. 6, and the parameter | index of resolution. [A] and [B] are diagrams showing a display example of an enlarged reconstructed image displayed on the display unit of FIG. Explanatory drawing explaining the designation | designated method which designates the site | part imaging | photography area | region formed by a cross section perpendicular | vertical with respect to the body-axis direction of a test subject as a high-resolution imaging | photography area | region. Explanatory drawing explaining the designation | designated method of designating a high-resolution imaging | photography area | region in three dimensions. The figure which shows the example of a display of the three-dimensional image displayed on the display part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray CT apparatus 11 Base 12 Computer apparatus 21 High voltage generation part 22 X-ray tube 23 X-ray detector 24 Data collection part 25 Base drive part 26 Bed drive part 27 Computer apparatus main body 28 Input part 29 Display part 31 Control part 32 Preprocessing unit 33 Storage unit 34 Reconstruction unit 35 Scano image data generation unit 36 Input data acquisition unit 37 Calculation unit 38 Setting unit

Claims (9)

Detecting means for detecting transmitted X-rays from a plurality of directions that are exposed from the X-ray source and transmitted through the subject;
A collecting means for collecting an X-ray detection signal from the transmitted X-ray;
Image data generating means for converting the X-ray detection signals collected by the collecting means into projection data, reconstructing the converted projection data and generating image data;
Display means for displaying an image based on the image data;
Imaging area instruction data acquisition means for acquiring imaging area instruction data for instructing a predetermined imaging area;
Center position coordinate calculation means for calculating coordinates of the center position of the predetermined shooting area based on the shooting area instruction data;
A bed movement amount setting means for setting a movement amount of a bed on which the subject is placed based on a calculation result by the center position coordinate calculation means;
An X-ray CT apparatus comprising: bed driving means for driving the bed in accordance with the movement amount of the bed set by the bed movement amount setting means. The detection unit detects transmitted X-rays from a plurality of directions that are exposed from an X-ray source and transmitted through a subject after the bed is moved by the bed driving unit. X-ray CT system. The bed movement amount setting means sets the movement amount of the bed based on the calculation result by the center position coordinate calculation means so that the center position of the predetermined imaging region matches the rotation center position when the scan is executed. The X-ray CT apparatus according to claim 1, wherein the X-ray CT apparatus is set. The image data displayed by the display means includes at least scano image data from two directions,
The X-ray CT apparatus according to claim 1, wherein the imaging area instruction data acquisition unit acquires the imaging area instruction data specified on the scano image data from the two directions. The image data displayed by the display means includes at least tomographic image data,
The X-ray CT apparatus according to claim 1, wherein the imaging region instruction data acquisition unit acquires the imaging region instruction data instructed on the tomographic image data. The image data displayed by the display means includes at least three-dimensional image data,
The X-ray CT apparatus according to claim 1, wherein the imaging region instruction data acquisition unit acquires the imaging region instruction data specified on the three-dimensional image data. The display means further includes a resolution indicator on the image superimposed on an image based on the image data displayed after the bed is moved by the bed driving means. The X-ray CT apparatus according to 1. 2. The X-ray CT apparatus according to claim 1, wherein the bed driving unit drives the bed up and down, right and left, and front and rear in accordance with the movement amount of the bed set by the bed movement amount setting unit. Detecting transmitted X-rays from a plurality of directions that are exposed from an X-ray source and transmitted through a subject, collect X-ray detection signals from the detected transmitted X-rays, and project the collected X-ray detection signals as projection data An image data generation step of converting the projection data into image data by reconstructing the converted projection data;
A display step of displaying an image based on the image data;
An imaging area instruction data acquisition step for acquiring imaging area instruction data for instructing a predetermined imaging area;
A center position coordinate calculating step for calculating coordinates of a center position of the predetermined shooting area based on the shooting area instruction data;
A bed movement amount setting step for setting a movement amount of a bed on which the subject is placed, based on a calculation result by the center position coordinate calculation unit;
A control processing program for an X-ray CT apparatus, which causes a computer to execute a bed driving step for driving the bed according to the movement amount of the bed set by the processing of the bed movement amount setting step.

Images