JP2005349096A - Radiation image processor, and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly set a CT reconfiguration range by continuously displaying a plurality of projection images in place of scanogram, while successively performing changeover. <P>SOLUTION: An image processing method comprises a step for continuously performing displaying on a display monitor, while successively changing over the plurality of projection images P1-Px (step S11); a step for setting the reconfiguration range by indicating a rectangular area A through the use of the continuously displayed projection images Q1 (step S12); a step for terminating the continuous display of the projection images P1-Px (step S13); and a final step for reconfigurating CT images R1-Ry from the projection images P1-Px in response to the reconfiguration range which is set in the step S12 (step S14). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radiographic image processing apparatus and an image processing method for obtaining a CT image by performing CT reconstruction based on a plurality of projection images photographed using a two-dimensional X-ray sensor.

  Conventionally, when a CT (Computer Tomography) image is reconstructed from a plurality of projection images having different projection directions, the reconstruction range is limited for the purpose of reducing the calculation time and the amount of generated data. . Therefore, the CT imaging apparatus generally displays a projection image in a specific projection direction as an image called a scanogram or a scout image, as shown in Patent Document 1, and uses this displayed scanogram to set a reconstruction range. It has a function to set.

JP-A-5-192327

  However, since only a projection image in a specific projection direction, mainly the front direction of the object to be inspected, is displayed as a scanogram, the operator can imagine the three-dimensional structure of the object to be inspected when setting the reconstruction range, It is necessary to set a wide reconstruction range with a margin.

  In order to imagine the three-dimensional structure of the object to be inspected, the operator requires a certain degree of knowledge and experience, and the reconstruction range cannot always be set appropriately. In addition, when a wide reconstruction range is set with a margin, there is a possibility that an unnecessary reconstruction range may be included, and there is a problem that it takes more time than necessary to generate a CT image.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to display a radiographic image processing apparatus and an image processing method for appropriately setting a CT reconstruction range by sequentially displaying a plurality of projection images while switching sequentially instead of a scanogram. Is to provide.

  In order to achieve the above object, a radiographic image processing apparatus according to the present invention is a radiographic image processing apparatus for reconstructing a CT image from a plurality of projection images, wherein the projection images are continuously displayed while sequentially switching the plurality of projection images. According to the image display means, the reconstruction range setting means for setting the CT reconstruction range using the projection image group displayed by the projection image display means, and the CT reconstruction range set by the reconstruction range setting means CT reconstruction means for reconstructing the CT image from the projected image is provided.

  The radiographic image processing method according to the present invention is a radiographic image processing method for reconstructing a CT image from a plurality of projection images. The radiographic image processing method continuously displays the plurality of projection images while sequentially switching the displayed projection images. A CT reconstruction range is set using a group, and the CT image is reconstructed from the projection image according to the set CT reconstruction range.

  According to the radiation image processing apparatus and the image processing method according to the present invention, the CT reconstruction range can be appropriately set by continuously displaying a plurality of projection images while sequentially switching instead of the scanogram.

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

  FIG. 1 shows a CT imaging apparatus 1 according to the first embodiment, which has a function of setting a CT reconstruction range by sequentially displaying a plurality of projection images while sequentially switching them. An X-ray generator 3 and a two-dimensional X-ray sensor 4 are arranged across the object S to be inspected on the rotating device 2, and the rotating device 2, the X-ray generator 3, and the two-dimensional X-ray sensor 4 collect data. It is electrically connected to the circuit 5.

  A pre-processing circuit 6 is connected to the data collecting circuit 5, and a CPU bus 7 is connected to the data collecting circuit 5 and the pre-processing circuit 6. The CPU bus 7 is connected to a CPU 8, various data, and a work memory. As a main memory 9 including an operation panel 10 for operating the entire apparatus, a pointing device 11, a display monitor 12, and an image processing circuit 13, a projection image display circuit 14 for continuously displaying a plurality of projection images while sequentially switching them. A reconstruction range setting circuit 15 for setting a reconstruction range using the continuously displayed projection images, and a reconstruction circuit 16 for reconstructing a CT image from a plurality of projection images according to the set reconstruction range are provided.

  The preprocessing circuit 6, the CPU 8, the main memory 9, the operation panel 10, the pointing device 11, the display monitor 12 and the image processing circuit 13 can exchange data with each other via the CPU bus 7.

  At the time of imaging, the CPU 8 activates the rotating device 2 and controls the X-ray generator 3 so as to emit the X-ray beam continuously or discontinuously while rotating the inspection object S. The X-ray generator 3 emits an X-ray beam to the inspection object S, and the emitted X-ray beam passes through the inspection object S while being attenuated, and reaches the two-dimensional X-ray sensor 4. During this operation state, that is, during CT scanning, the two-dimensional X-ray sensor 4 sequentially acquires projection images, and sequentially transmits the acquired projection image data to the data acquisition circuit 5. Further, in this case, the inspection object S may be fixed and the X-ray generator 3 and the two-dimensional X-ray sensor 4 may be rotated. In the embodiment, the inspection object S is a human body, and the projection image output from the two-dimensional X-ray sensor 4 is a human body image such as a chest image, for example.

  For example, 1000 projection images are sent to the data collection circuit 5 while the inspection object S rotates 360 degrees, the data collection circuit 5 sends image data to the preprocessing circuit 6, and the preprocessing circuit 6 Processing is performed, and projection data is sent to the image processing circuit 13 and / or the main memory 9. By such a photographing operation, projected images photographed from different directions are sequentially transferred to the image processing circuit 13 and simultaneously sent to the main memory 9 and stored therein.

  The data acquisition circuit 5 converts the projection image output from the two-dimensional X-ray sensor 4 into an electrical signal and supplies it to the preprocessing circuit 6, and the preprocessing circuit 6 applies the projection image signal from the data acquisition circuit 5 to the projection image signal. Pre-processing such as offset correction processing and gain correction processing is performed. The projection image signal subjected to the preprocessing is transferred as a projection image to the main memory 9 and the image processing circuit 13 via the CPU bus 7 under the control of the CPU 8.

  In the present embodiment, the two-dimensional X-ray sensor 4, the data acquisition circuit 5, and the preprocessing circuit 6 are separated, but the two-dimensional X-ray sensor 4, the data acquisition circuit 5, and the preprocessing circuit 6 are arranged as sensors. As a unit, you may comprise in the same unit.

  FIG. 2 is an explanatory diagram of an example of the projection images P1 to Px processed by the preprocessing circuit 6. FIG. 3 shows an example of a rectangular area instructed by the operator from the operation panel 10 when setting the reconstruction range by the reconstruction range setting circuit 15, and Q1 is continuously displayed while being sequentially switched by the projection image display circuit 14. A projected image A is a rectangular area designated by the operator as a reconstruction range. FIG. 4 shows CT images R1 to Ry obtained by reconstructing the projection images P1 to Px.

  FIG. 5 is a processing flowchart in the image processing circuit 13. The program code according to the flowchart is stored in the main memory 9 or a ROM (not shown), and is read and executed by the CPU 8. The image processing circuit 13 that sequentially receives the plurality of projection images P1 to Px processed by the preprocessing circuit 6 via the CPU bus 7 displays the display monitor while sequentially switching the projection images P1 to Px by the projection image display circuit 14. 12 is continuously displayed (step S11).

  Next, the reconstruction area setting circuit 15 instructs the rectangular area A of the reconstruction area using the continuously displayed projection image Q1, and sets the reconstruction area based on the designated rectangular area A (step S12). ). Here, for example, a method of specifying the upper left and lower right of the rectangular area A using the pointing device 11 is used as an instruction method for the rectangular area A.

  Subsequently, the continuous display of the projection images P1 to Px started in step S11 is terminated (step S13). Finally, according to the reconstruction range set in step S12, the reconstruction circuit 16 reconstructs CT images R1 to Ry from the projection images P1 to Px (step S14).

  FIG. 6 is an operation flowchart of the projection image display circuit 14 regarding the start of continuous display of projection images in step S11 and the end of continuous display of projection images in step S13. First, a plurality of projection images P1 to Px processed by the preprocessing circuit 6 are sequentially received via the CPU bus 7 under the control of the CPU 8 (step S21), and the total number of projection images P1 to Px received at this time is calculated. Store as I.

  Subsequently, a serial number i for identifying each of the projection images P1 to Px is assigned (step S22). Here, i is a value from 0 to (I-1), and for example, it is incremented by 0 to 1 in the order in which the projection image display circuit 14 received the projection images P1 to Px in step S21.

  Next, in steps S23 to S27, the projection images P1 to Px are continuously displayed while being sequentially switched, and the presence or absence of a continuous display end instruction is monitored between the display of the projection images P1 to Px. When S25 exists and there is an end instruction, the operation of the projection image display circuit 14 is ended.

  The generation of the end instruction may be automatically generated in step S13 immediately after the rectangular area A of the reconstruction range is set in step S12 in the flowchart of FIG. 5, or may be manually input by the operator. May be generated.

  By the operation of the projection image display circuit 14 as described above, a plurality of projection images P1 to Px are sequentially switched until the setting of the rectangular area A is completed, and is displayed on the display monitor 12 as a moving image.

  Finally, in step S14, the reconstruction circuit 16 reconstructs the CT images R1 to Ry from the projection images P1 to Px according to the rectangular area A obtained in step S13, but the CT image group is obtained by CT reconstruction from the projection image group. Since the method for obtaining the value is generally well known, the description thereof is omitted.

  As described above, according to the first embodiment, by continuously displaying a plurality of projection images P1 to Px having different projection directions while sequentially switching, the operator can set the reconstruction range appropriately and easily. This has the effect of optimizing the calculation time and the amount of generated data that have conventionally been wasted, and as a result, the CT inspection throughput is improved.

  FIG. 7 shows a CT imaging apparatus 21 according to the second embodiment. The difference from the CT imaging apparatus 1 according to the first embodiment is that a projection image selection circuit 23 is added to the image processing circuit 22. In the following, the projection image selection circuit 23 and parts related thereto will be mainly described.

  Similar to the first embodiment, the operations from the radiation of the X-ray beam to the transfer of the projection image are repeatedly performed continuously while the rotation device 2 is operated, and the projection images P1 to Px photographed from different directions are sequentially applied to the image processing circuit. 22 for transfer.

  FIG. 8 is a flowchart showing the operation of the image processing circuit 22. The image processing circuit 22 that has sequentially received the plurality of projection images P1 to Px processed by the preprocessing circuit 6 through the CPU bus 7 under the control of the CPU 8 is continuously connected to the display monitor 12 by the projection image selection circuit 23 first. A plurality of projection images to be displayed are determined (step S31). Subsequently, the plurality of projection images selected in step S31 are input to the projection image display circuit 14, and are continuously displayed on the display monitor 12 while being sequentially switched (step S32). Hereinafter, steps S32 to S34 are the same as steps S13 to S15 in the first embodiment.

  FIG. 9 is a flowchart of the operation of the projection image selection circuit 23 in step S31 of FIG. First, a plurality of projection images P1 to Px processed by the preprocessing circuit 6 are sequentially received via the CPU bus 7 under the control of the CPU 8 (step S41), and the total number of projection images received at this time is represented by J (for example, J = 1000).

  Subsequently, a serial number j for identifying each projection image is assigned (step S42). Here, j is set to a value of 0 to (J−1), and is given by increasing by 0 to 1 in the order in which the projection image selection circuit 23 receives the projection image in step S41, for example.

  Next, the number N of display images used for continuous projection image display is input (step S43). The number N of display images may be input manually by the operator using the operation panel 10 or a predetermined constant may be automatically input. In addition, a numerical value calculated based on the processing speed of the projection image display circuit 14 can be automatically input. For example, a numerical value such as N = 200 is input.

  Subsequently, a display skip value s is obtained as s = J / N using the total number J of projection images obtained in step S41 and the number N of display images obtained in step S43 (step S44). The display skip value 5 is a parameter representing the frequency with which the input projected images P1 to Px are used for continuous display in step S32. Represents that one image is used for continuous display.

  Actually, in subsequent steps S45 to S48, processing for adding the projection image j to the display target projection image list as shown in FIG. 10 is performed every display skip value s.

  When selection of all projection images is completed in step S48, a part of the projection images P1 to Px is output to the projection image display circuit 14 based on the finally completed display target projection image list (step S49). The operation of the projection image selection circuit 23 is finished.

  As described above, by the operation of the projection image selection circuit 23, a part of the projection images P1 to Px input to the image processing circuit 22 is selected and sequentially switched by the projection image display circuit 14 to be displayed on the display monitor 12 as a moving image. Is displayed. The continuous display of the projected image is continued until the setting of the rectangular area A is completed as in the first embodiment.

  According to the second embodiment, by continuously displaying a plurality of projection images having different projection directions while sequentially switching, there is an effect that the operator can set the reconstruction range appropriately and simply. By using a relatively small number of projection images, the calculation load is reduced and high-speed display is possible. In addition, since the reconstruction process is performed using an appropriately set reconstruction range, similarly to the first embodiment, the calculation time and the amount of generated data that have conventionally been wasted can be optimized, and as a result, CT inspection is performed. Improve throughput.

  An object of the present invention is to supply a storage medium storing a program code of software for realizing the functions of the apparatus or system of the embodiment to the apparatus or system, and a computer (CPU or MPU or the like) of the apparatus or system. It is also achieved by reading and executing the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the function of the first embodiment, and the storage medium storing the program code and the program code constitute the present invention.

  As a storage medium for supplying the program code, a ROM, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, or the like may be used. it can.

  Further, by executing the program code read by the computer, not only the functions of the embodiments are realized, but also the OS or the like running on the computer based on the instruction of the program code performs one of the actual processes. A case where the function of the embodiment is realized by performing part or all of the processing is also included in the embodiment of the present invention.

  Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. A case where the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing and the functions of the embodiments are realized by the processing is also included in the embodiment of the present invention.

  When the present invention is applied to such a program or a storage medium storing the program, the program is, for example, a program code corresponding to the flowchart shown in FIG. 5, FIG. 6, FIG. 8, or FIG. Consists of

1 is a block configuration diagram of Embodiment 1. FIG. It is explanatory drawing of a projection image. It is explanatory drawing of the rectangular area which the operator displayed the projection image displayed continuously and the operator. It is explanatory drawing of a CT image. FIG. 3 is a processing flowchart of the image processing circuit according to the first exemplary embodiment. FIG. 5 is a flowchart of processing performed by a projection image display circuit according to the first embodiment. FIG. 6 is a block diagram of a second embodiment. FIG. 10 is a flowchart of processing performed by an image processing circuit according to the second exemplary embodiment. FIG. 10 is a flowchart of processing performed by a projection image selection circuit according to the second embodiment. It is explanatory drawing of the display target projection image list | wrist of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,21 CT imaging device 2 Rotating device 3 X-ray generator 4 Two-dimensional X-ray sensor 5 Data acquisition circuit 6 Pre-processing circuit 7 CPU bus 8 CPU
9 Main Memory 10 Operation Panel 11 Pointing Device 12 Display Monitor 13, 22 Image Processing Circuit 14 Projected Image Display Circuit 15 Reconstruction Range Setting Circuit 16 Reconstruction Circuit 23 Projected Image Selection Circuit

Claims (7)

  A radiographic image processing apparatus for reconstructing a CT image from a plurality of projection images, the projection image display means for continuously displaying the plurality of projection images while sequentially switching, and a projection image group displayed by the projection image display means Reconstructing range setting means for setting a CT reconstruction range using the CT, and CT reconstruction means for reconstructing the CT image from the projection image according to the CT reconstruction range set by the reconstruction range setting means A radiographic image processing apparatus characterized by that.   2. The projection image selection means for selecting the projection image to be displayed, wherein the projection image display means continuously displays the projection images selected by the projection image selection means while sequentially switching them. The radiation image processing apparatus described.   Display image number input means for inputting the number of display images of the projection image, and the projection image selection means selects the projection image to be displayed based on the number of display images input by the display image number input means. The radiographic image processing apparatus according to claim 2.   An X-ray generation source for irradiating the object to be inspected, a rotating means for relatively rotating the object to be inspected in the radiation emitted by the X-ray generation source, and detecting the radiation and acquiring the projection image The radiation image processing apparatus according to any one of claims 1 to 3, further comprising a two-dimensional X-ray sensor.   A radiographic image processing method for reconstructing a CT image from a plurality of projection images, wherein the plurality of projection images are sequentially displayed while being sequentially switched, and a CT reconstruction range is set using the displayed projection image group, A radiographic image processing method, wherein the CT image is reconstructed from the projection image in accordance with the set CT reconstruction range.   A program for causing a computer to execute a predetermined method, wherein the predetermined method includes each step in the image processing method according to claim 5.   A computer-readable medium storing the program according to claim 6.

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