JP2006288908A - Medical diagnostic imaging equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To position an intended section to a detection part in medical diagnostic imaging equipment quickly, easily, and at low cost; and to eliminate mix-up of image data from subjects by making it easy to identify the subjects. <P>SOLUTION: The medical diagnostic imaging equipment which comprises a gantry incorporating a detection part which detects signals such as electromagnetic waves and radiation from a subject, a table which has the subject on it and can carry the subject to the detection part of the gantry, a table control means which drives/controls the movement of the table, and an image forming means that processes data detected from the detection part and forms an tomographic image of the imaged section of the subject has a video camera for imaging the subject placed on the table, a display means to display the subject's image taken by the video camera, an indication means to indicate a desired section imaged on the subject's image, and a means to obtain a position coordinate on the table corresponding to the position on the subject's image indicated above. The table control means moves the position of the position coordinate on the table to the detection section of the gantry. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to medical image diagnostic apparatuses such as X-ray CT, positron CT, and MRI, and more particularly to a medical image diagnostic apparatus that facilitates movement of a subject to a detection unit of these apparatuses.

  Medical diagnostic imaging devices such as X-ray CT, positron CT, and MRI measure X-rays that pass through the subject in X-ray CT, and measure γ-rays of radioisotopes administered to the subject in positron CT. The MRI apparatus measures the nuclear magnetic resonance signal generated from the subject due to the nuclear magnetic resonance phenomenon, and images it based on the measured signals such as radiation and high-frequency magnetic field. A detection unit for measuring the image and an image processing device for processing and imaging data from the detection unit. The detection unit is built in a cover made of FRP or the like, usually called a gantry, and moves and measures a subject laid on a table in the gantry.

  In such a medical image diagnostic apparatus, it is necessary that the part to be measured of the subject is located in the detection unit, and it is difficult to perform alignment in a state where it is inserted into the gantry. Prior to moving the gantry to the gantry, the subject and the apparatus are aligned, and a predetermined amount of the subject is moved from that position so that the desired part of the subject is positioned in the detection unit.

  For example, a conventional MRI apparatus is provided with a projector that illuminates a subject and designates a movement start position of a table on the front side of a gantry including a static magnetic field generation source that generates a static magnetic field. A moving amount measuring unit that measures the moving amount and obtains the measured value and a moving control unit that drives and controls the movement of the table based on the measured value are provided.

In such an MRI apparatus, the subject is positioned in the static magnetic field space where the detection unit is located as follows. That is, first, the subject is placed on the table and the table is moved up and down to a predetermined position. Next, in a state where the subject is laid on the table, the table is moved so that the light of the projector hits a desired part of the subject to be imaged. Next, the position of the part to be imaged is set by applying light from the projector to a desired part of the subject. Next, the table on which the subject is placed is moved to the detection unit. Since the distance between the projector and the detector is determined when the apparatus is designed, the table is moved in the horizontal direction by this distance. At this time, the table is automatically moved until the movement amount of the table from the movement amount measuring means reaches a predetermined movement amount, and the movement of the table is stopped immediately after the movement amount reaches a predetermined value. In this way, alignment of a desired part of the subject is performed. Thereafter, a tomographic image of a desired part is taken.
Such alignment between the detection unit and the desired part of the subject is performed in substantially the same manner in X-ray CT and positron CT.

  However, in the above prior art, it is necessary to first position the table at a certain initial position of the projector and set a desired imaging region with the projector, and it takes time to align the region of the subject and the detection unit. There is a problem of complexity.

In order to solve this problem, (Patent Document 1) includes an indicator with a built-in point light source for pointing an imaging region of a subject placed on a table, and a coordinate system including a detection unit. A video camera that is installed at a position and captures the light emitted from the indicator, processes the image captured by the video camera, calculates coordinates on the image of the point light source, and based on the coordinates, the imaging part of the subject is detected And a computer that calculates the amount of movement of the table until reaching the position, and the table drive means discloses a medical image diagnostic apparatus that moves the table based on the amount of movement determined by the computer.
JP-A-81-263838

  However, in the medical diagnostic imaging apparatus disclosed in the above (Patent Document 1), it is necessary to prepare an indicator with a built-in light source, process an image captured by a video camera, and calculate coordinates on the image of the point light source. For this reason, the means for aligning the subject with the detection unit increases the cost, and image processing also takes time. That is, there remains a problem to be solved in that the subject is easily aligned with the detection unit at low cost.

  An object of the present invention is to provide a medical image diagnostic apparatus capable of quickly aligning a desired part of a subject with a detection unit easily at low cost.

  In order to achieve the above object, the medical image diagnostic apparatus of the present invention is configured as follows. That is, a gantry that includes a detection unit that detects signals such as electromagnetic waves and radiation from the subject, a table on which the subject is placed, and the subject can be moved to the detection unit of the gantry, and the movement of the table A table control means for driving / controlling the image, and an image forming means for processing the detection data from the detection section to create a tomographic image of the imaging region of the subject, and further, the subject placed on the table , A display means for displaying a subject image taken by the video camera, an instruction means for instructing a desired imaging part on the subject image, and the indicated position on the subject image Means for obtaining position coordinates on the table corresponding to the table, and the table control means moves the position coordinates on the table to the detection unit of the gantry.

  According to the medical image diagnostic apparatus of the present invention, a desired part of a subject can be quickly aligned with a detection unit easily at low cost, and an operation for alignment can be facilitated. .

  Hereinafter, an MRI apparatus is taken as an example of a medical image diagnostic apparatus, and a preferred embodiment of the medical image diagnostic apparatus of the present invention will be described in detail according to the accompanying drawings. However, the present invention is not limited to the MRI apparatus, but can be applied to other medical image diagnostic apparatuses such as an X-ray CT apparatus and a positron CT apparatus. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments of the invention, and the repetitive description thereof is omitted.

First, an overall outline of an MRI apparatus to which the present invention is applied will be described.
FIG. 1 is a block diagram showing an overall configuration of an example of an MRI apparatus to which the present invention is applied. This MRI apparatus uses a nuclear magnetic resonance (NMR) phenomenon to obtain a tomographic image of a subject.As shown in FIG. 7, the MRI apparatus includes a static magnetic field generation system 2, a gradient magnetic field generation system 3, A transmission system 5, a reception system 6, a signal processing system 7, a sequencer 4, and a central processing unit (CPU) 8 are provided.

  The static magnetic field generation system 2 generates a uniform static magnetic field in the direction perpendicular to the body axis in the space around the subject 1 if the vertical magnetic field method is used, and in the direction of the body axis if the horizontal magnetic field method is used. Thus, a permanent magnet type, normal conducting type or superconducting type static magnetic field generating source is arranged around the subject 1. The static magnetic field generation system 2 is accommodated in the gantry 51.

  The gradient magnetic field generating system 3 includes a gradient magnetic field coil 9 wound in the three-axis directions of X, Y, and Z, which is a coordinate system (stationary coordinate system) of the MRI apparatus, and a gradient magnetic field power source 10 that drives each gradient magnetic field coil. The gradient magnetic fields Gx, Gy, Gz are applied in the three axis directions of X, Y, and Z by driving the gradient magnetic field power supply 10 of each coil in accordance with a command from the sequencer 4 described later. At the time of imaging, a slice direction gradient magnetic field pulse (Gs) is applied in a direction orthogonal to the slice plane (imaging cross section) to set a slice plane for the subject 1, and the remaining two orthogonal to the slice plane and orthogonal to each other A phase encoding direction gradient magnetic field pulse (Gp) and a frequency encoding direction gradient magnetic field pulse (Gf) are applied in one direction, and position information in each direction is encoded into an echo signal. The gradient magnetic field coil 9 is accommodated in the gantry 51, and the gradient magnetic field power source 10 is accommodated in the casing 53.

  The sequencer 4 is a control means that repeatedly applies a high-frequency magnetic field pulse (hereinafter referred to as “RF pulse”) and a gradient magnetic field pulse in a predetermined pulse sequence, and operates under the control of the CPU 8 to collect tomographic image data of the subject 1. Various commands necessary for the transmission are sent to the transmission system 5, the gradient magnetic field generation system 3, and the reception system 6. The sequencer 4 is accommodated in the housing 53.

  The transmission system 5 irradiates the subject 1 with RF pulses in order to cause nuclear magnetic resonance to occur in the nuclear spins of the atoms constituting the living tissue of the subject 1, and includes a high frequency oscillator 11, a modulator 12, and a high frequency amplifier. 13 and a high frequency coil (transmission coil) 14a on the transmission side. The high-frequency pulse output from the high-frequency oscillator 11 is amplitude-modulated by the modulator 12 at a timing according to a command from the sequencer 4, and the amplitude-modulated high-frequency pulse is amplified by the high-frequency amplifier 13 and then placed close to the subject 1. By supplying to the high frequency coil 14a, the subject 1 is irradiated with the RF pulse. In general, the high-frequency coil 14 a is accommodated in the gantry 51, and the others are accommodated in the housing 53.

  The receiving system 6 detects an echo signal (NMR signal) emitted by nuclear magnetic resonance of nuclear spins constituting the biological tissue of the subject 1, and receives a high-frequency coil (receiving coil) 14b on the receiving side and a signal amplifier 15 And a quadrature phase detector 16 and an A / D converter 17. The NMR signal of the response of the subject 1 induced by the electromagnetic wave irradiated from the high-frequency coil 14a on the transmission side is detected by the high-frequency coil 14b disposed close to the subject 1 and amplified by the signal amplifier 15, The signal is divided into two orthogonal signals by the quadrature detector 16 at the timing according to the command from the sequencer 4, and each signal is converted into a digital quantity by the A / D converter 17 and sent to the signal processing system 7. Generally, the device group constituting the receiving system 6 is accommodated in a gantry 51.

  The signal processing system 7 performs various data processing and display and storage of processing results, and has an external storage device such as an optical disk 19 and a magnetic disk 18 and a display 20 composed of a CRT, etc. Is input to the CPU 8, the CPU 8 executes processing such as signal processing and image reconstruction, and displays the tomographic image of the subject 1 as a result on the display 20, and the magnetic disk 18 of the external storage device. Record in etc. The signal processing system 7 is accommodated in the processing device 54.

  The table 30 places and moves the subject 1 in the static magnetic field space (measurement space) generated by the static magnetic field generation system 2. That is, the table 30 moves continuously or intermittently in the body axis direction of the subject 1 or in a direction perpendicular to the body axis direction on the table 31 in which the drive unit controlled by the CPU 8 is built. The table 30 or 31 has a built-in position detector (not shown) to detect at least one of {position coordinates} and {movement direction and amount} of the table 30, and send the information to the CPU 8. To do.

  The operation unit 25 inputs various control information of the MRI apparatus and control information of processing performed in the signal processing system 7, and includes a trackball or mouse 23 and a keyboard 24. The operation unit 25 is disposed close to the display 20, and the operator controls various processes of the MRI apparatus interactively through the operation unit 25 while looking at the display 20.

  The video camera 40 is a video camera that captures the appearance of a subject, and includes a circuit that digitizes the video signal, and digitized image information is input to the CPU 8. The CPU 8 processes the image information and stores it on the magnetic disk 18, for example. The video camera 40 is fixedly disposed at a position on the gantry surface of the MRI apparatus or in the vicinity of the gantry as required, so that the appearance of the subject can be photographed.

  In FIG. 1, the high-frequency coil 14a and the gradient magnetic field coil 9 on the transmission side are within the static magnetic field space that is the inspection unit of the static magnetic field generation system 2 into which the subject 1 is inserted. Opposite to 1, the horizontal magnetic field system is installed so as to surround the subject 1. The high-frequency coil 14b on the receiving side is installed so as to face or surround the subject 1.

  At present, the radionuclide to be imaged by the MRI apparatus is a hydrogen nucleus (proton) which is a main constituent material of the subject as being widely used clinically. By imaging information on the spatial distribution of proton density and the spatial distribution of relaxation time in the excited state, the form or function of the human head, abdomen, limbs, etc. is imaged two-dimensionally or three-dimensionally.

  Next, a first embodiment of the medical image diagnostic apparatus of the present invention will be described. In the present embodiment, a desired part to be imaged is indicated on an image of a subject taken from a video camera, and the indicated part is moved to an examination unit.

  An example of this embodiment will be described with reference to FIG. FIG. 2 shows an example in which an image obtained by photographing a subject lying on a table with a video camera attached to the side surface of the gantry is displayed on a monitor, and a desired imaging portion of the subject is indicated on the monitor.

  In FIG. 2 (a), a pair of static magnetic field generation sources 201 and 202 that generate a static magnetic field are arranged opposite to each other with the inspection unit interposed therebetween in an inspection unit (static magnetic field space) where the subject 1 is disposed. In the so-called open type MRI apparatus having the configuration, an example in which the video camera 40 is arranged on the upper magnetic field generation source 201 on the gantry side surface is shown. After moving the subject 1 placed on the table 30 to a predetermined position, the video camera 40 images the subject 1 from above. The position where the video camera 40 is arranged is not limited to the side surface of the gantry, and may be fixed to either one of the ceiling or the table 30 using a tripod or the like. Further, the MRI apparatus may be not only an open type but also a so-called tunnel type MRI apparatus that generates a horizontal magnetic field.

  In FIG. 2 (b), an image photographed by the video camera 40 is displayed on the display 20, and a desired part 204 to be imaged is designated on the subject image displayed on the display 20. The designation is performed using, for example, the mouse 23 or the keyboard 24. On the magnetic disk 18 (not shown), the correspondence between the coordinates of the points on the image of the display 20 and the position coordinates on the table 30 is stored as a numerical table or conversion function, and the CPU 8 stores the numerical table or conversion. With reference to the function, the position coordinates on the table corresponding to the point 204 are obtained from the point 204 specified on the image of the display 20.

  As described above, since the table is moved to a predetermined position before the subject 1 is imaged by the video camera 40, the distance between each position coordinate on the table 30 at the predetermined position and the center of the static magnetic field that is the center of the inspection unit. Is determined at the time of designing the MRI apparatus. Based on the design data, the distance between each position coordinate on the table 30 and the center of the static magnetic field, and the table 30 for horizontally moving each position coordinate to the center of the static magnetic field. The amount of movement is prepared in advance for each position coordinate on the table 30 and stored in, for example, the magnetic disk 18.

FIG. 3 shows an example of the coordinate point 301 on the table 30 corresponding to the desired imaging region 204 designated on the display 20. FIG. 3 shows a view of the lower static magnetic field generation source 202 and the table 30 from the examination space side between the pair of static magnetic field generation sources 201 and 202 shown in FIG. 2 (a). The distance 313 between the coordinate point 301 and the static magnetic field center 302 on the table 30 arranged at a predetermined position, and the amount of movement 311 in the longitudinal direction of the table 30 for moving the coordinate point 301 to the static magnetic field center 302 and perpendicular thereto. Since the amount of movement 312 in any direction is determined when the MRI apparatus is designed, these values are stored in advance in the magnetic disk 18 or the like as a numerical table or a conversion function. The CPU 8 controls the movement of the table 30 using the movement amount data or the conversion function stored in the numerical table.
Here, the predetermined position of the table 30 can be a position where the left end of the table 30 is in contact with the outer periphery of the gantry as shown in FIG. 30, for example.

  Further, as described above, the table 30 or the table 31 includes a position detector for the table 30 (not shown), and the CPU 8 monitors information on the table position or the table movement amount from the position detector as needed. The movement of the table 30 is controlled, and the movement of the table 30 is stopped immediately after the movement amount read from the numerical table or the movement amount obtained using the conversion function is reached. At that time, the position coordinates 301 on the table reach the static magnetic field center 302.

  Each process described above is summarized in a flowchart as shown in FIG. Hereinafter, each processing step of the present embodiment will be described based on the flowchart shown in FIG.

In step 401, the subject 1 is placed on the table 30.
In step 402, the table 30 is moved to a predetermined position. The predetermined position of the table 30 may be a position where the left end of the table 30 contacts the outer periphery of the gantry, for example.
In step 403, the subject 1 is photographed by the video camera 40 and displayed on the display 20.
In step 404, a desired imaging region is designated on the screen of the display 20. The designation is performed using, for example, the mouse 23 or the keyboard 24.

In step 405, position coordinates on the table 30 corresponding to the position on the screen designated in step 404 are obtained.
In step 406, the position coordinates on the table 30 obtained in step 405 are moved to the center of the static magnetic field.
In step 407, imaging of a desired imaging region is started.

  As described above, according to the present embodiment, a desired imaging region of the subject can be easily and quickly aligned with the detection unit. In addition, an operation for alignment can be facilitated. In particular, this embodiment can be realized at low cost because it can be realized by preparing an inexpensive video camera for imaging a subject and an apparatus (electronic circuit) for converting the video signal into a digital signal.

Next, a second embodiment of the medical image diagnostic apparatus of the present invention will be described. In this embodiment, a face image of a subject photographed by a video camera is used for subject identification.
An object of the present embodiment is to easily identify a subject when diagnosing a tomographic image, and to easily prevent a mistake in taking a tomographic image to be diagnosed. This is to cope with the recent frequent occurrence of mistakes in subjects and the frequent diagnosis of tomographic images of different subjects.

  An example of this embodiment will be described with reference to FIG. FIG. 5 shows a tomographic image obtained by actually capturing a face image obtained by photographing the face of the subject with the video camera 40, for example, stored in the magnetic disk 18, and reading these images again and displaying them on the display 20 for imaging. In this example, a face image taken with a video camera is displayed together when diagnosing the tomographic image.

  The face image of the subject 1 using the video camera 40 is taken either before or after taking a tomographic image of the subject. The captured face image may be displayed on the display 20. At that time, the captured tomographic image may be displayed at the same time. Then, the photographed face image, the photographed tomographic image, and preferably the attribute information (identification number, name, address, birthday, etc.) of the subject are stored in the magnetic disk 18 in association with each other.

  When imaging is completed and the captured tomographic image is diagnosed, it may be displayed on the display 20 of the same device or may be displayed on another display. At that time, it is possible to easily identify whether or not they are the same subject by simultaneously displaying the face image and comparing it with the actual face of the subject facing each other.

The above processing steps can be summarized as a flowchart shown in FIG. Hereinafter, each processing step of the present embodiment will be described based on the flowchart shown in FIG.
In step group 601, a face image of the subject and a desired part are imaged. Specifically, a desired part of the subject is imaged at step 601-1 and a face image of the subject is captured at step 601-2.
Note that the processing order of step 601-1 and step 601-2 may be any first. Finally, in step 601-3, the face image and the tomographic image are stored in association with each other. For example, it can be stored on the magnetic disk 18.

  In step group 602, the subject is identified and the tomographic image taken is diagnosed. Specifically, in step 602-1, the face image and the tomographic image are read from, for example, the magnetic disk 18 and displayed. The display is made on the display 20, for example. Only the face image may be displayed. The face image displayed in step 602-2 is collated with the actual subject's face. If it is the same subject, the process proceeds to Step 602-3 to diagnose a tomographic image. If it is not the same subject, the tomographic image is not diagnosed.

  As described above, according to the present embodiment, it is possible to easily identify a subject when diagnosing a tomographic image, and avoid performing a misdiagnosis using a tomographic image of a different subject. It becomes possible to do. Alternatively, it is possible to easily prevent an error in taking a tomographic image to be diagnosed.

1 is a block diagram showing the overall configuration of an embodiment of an MRI apparatus according to the present invention. FIG. 3 is a diagram illustrating an example of the first embodiment of the present invention, and is a schematic diagram illustrating setting of a subject based on an image obtained by photographing the subject. The figure which shows the relationship between the desired imaging | photography site | part of a subject and a static magnetic field center. 5 is a flowchart showing a processing flow of an example of the first embodiment of the present invention. FIG. 10 is a diagram showing an example of the second embodiment of the present invention, and is a schematic diagram showing identification of a subject based on a face image of the subject. 9 is a flowchart showing a processing flow of an example of the second embodiment of the present invention.

Explanation of symbols

  1 subject, 2 static magnetic field generation system, 3 gradient magnetic field generation system, 4 sequencer, 5 transmission system, 6 reception system, 7 signal processing system, 8 central processing unit (CPU), 9 gradient magnetic field coil, 10 gradient magnetic field power supply, 11 High-frequency transmitter, 12 Modulator, 13 High-frequency amplifier, 14a High-frequency coil (transmitting coil), 14b High-frequency coil (receiving coil), 15 Signal amplifier, 16 Quadrature detector, 17 A / D converter, 18 Magnetic disk, 19 optical disk, 20 display, 21 ROM, 22 RAM, 23 trackball or mouse, 24 keyboard, 30 table

Claims (1)

A gantry with a built-in detection unit that detects signals such as electromagnetic waves and radiation from the subject, a table on which the subject is placed, the subject can be moved to the detection unit of the gantry, and the movement of the table is driven A medical image diagnostic apparatus comprising: a table control unit to control; and an image forming unit that processes detection data from the detection unit to create a tomographic image of an imaging region of a subject.
A video camera for photographing a subject placed on the table, a display means for displaying a subject image photographed by the video camera, an instruction means for instructing a desired imaging part on the subject image, and Means for obtaining position coordinates on the table corresponding to the position on the inspected subject image,
The medical image diagnostic apparatus, wherein the table control means moves a position coordinate position on the table to a detection unit of the gantry.

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