JP5762121B2 - X-ray CT system - Google Patents

Description

  The present invention relates to an X-ray CT (Computed Tomography) apparatus, and more particularly to a technique that supports imaging of the heart.

  When the heart is imaged using an X-ray CT apparatus, in order to reduce so-called respiratory motion artifacts, the subject is held to hold his / her breath, and the scan is executed with the movement of the thorax minimized. In addition, in order to reduce motion artifacts caused by the movement of the heart, it is necessary to set an appropriate scan speed according to the heart rate of the subject. Furthermore, it is desirable that the heart rate during the scan is stable in order to keep the image quality of the obtained image good. Since the heart rate may fluctuate during breath holding, and how it fluctuates depends on the subject, in Patent Document 1, the subject is practicing breath holding prior to the main scan, and during breath holding practice The shooting conditions are set according to the fluctuation of the heart rate measured.

International Publication WO2005 / 089651 Publication

  However, Patent Document 1 does not clarify how to set the breath holding practice time. Since the time required for the heart rate to stabilize after the start of breath holding varies from person to person, if the same breath holding practice time is set for all subjects, the process related to breath holding practice is wasted. Will occur. For example, if a breath holding exercise that is too long is performed on a subject with a fast heart rate stability, the breath holding exercise after the heart rate is stabilized is wasted.

  Accordingly, an object of the present invention is to provide an X-ray CT apparatus that improves the efficiency of processes related to breath holding practice.

  In order to achieve the above object, the present invention is an X-ray CT apparatus for measuring X-ray transmission distribution data of a subject together with the heart rate of the subject, and a breath holding practice executed prior to a main scan Setting means for setting a breath holding practice time corresponding to the subject, and a notifying means for notifying the subject of the start and end of the breath holding practice based on the set breath holding practice time It is characterized by that.

  According to the present invention, it is possible to provide an X-ray CT apparatus capable of improving the efficiency of processes related to breath holding practice.

The block diagram which shows the whole structure of the X-ray CT apparatus of this invention Front view of the X-ray CT apparatus of the present invention The figure which shows the whole flow of 1st embodiment of this invention. The figure which shows the flow of a process of the principal part of 1st embodiment of this invention. The figure which shows the example of a screen display of 1st embodiment of this invention The figure which shows the flow of a process of the principal part of 2nd embodiment of this invention. The figure which shows the example of a screen display of 2nd embodiment of this invention The figure which shows the flow of a process of the principal part of 3rd embodiment of this invention. The figure which shows the example of the data table of 3rd embodiment of this invention. The figure which shows the flow of a process of the principal part of 4th embodiment of this invention. The figure which shows the example of a screen display of 4th embodiment of this invention

  Hereinafter, preferred embodiments of an X-ray CT apparatus according to the present invention will be described with reference to the accompanying drawings. In the following description and the accompanying drawings, the same reference numerals are given to the constituent elements having the same functional configuration, and redundant description will be omitted.

{First embodiment}
FIG. 1 is a block diagram showing the overall configuration of the X-ray CT apparatus. As shown in FIG. 1, the X-ray CT apparatus 1 includes a scan gantry unit 100 and an operation unit 120.

  The scan gantry unit 100 includes an X-ray tube device 101, a rotating disk 102, a collimator 103, an X-ray detector 106, a data collection device 107, a bed device 105, a gantry control device 108, and a bed control device 109. An X-ray control device 110, an input / output device 111, and an electrocardiographic data acquisition device 112.

  The X-ray tube apparatus 101 is an apparatus that irradiates a subject placed on the bed apparatus 105 with X-rays. The collimator 103 is a device that limits the radiation range of X-rays emitted from the X-ray tube device 101. The rotating disk 102 is provided with an opening 104 through which a subject placed on a bed apparatus 105 enters, and an X-ray tube device 101 and an X-ray detector 106 are mounted to rotate around the subject. It is. The X-ray detector 106 is a device that measures the spatial distribution of transmitted X-rays by detecting X-rays that are placed opposite to the X-ray tube device 101 and transmitted through the subject, and rotates a large number of detection elements. One is arranged one-dimensionally in the rotation direction of the disk 102, or a plurality of detection elements are arranged two-dimensionally in the rotation direction of the rotation disk 102 and the rotation axis direction. The data collection device 107 is a device that collects the X-ray dose detected by the X-ray detector 106 as digital data. The gantry control device 108 is a device that controls the rotation and inclination of the rotary disk 102. The bed control device 109 is a device that controls the vertical and horizontal movements of the bed device 105. The X-ray control device 110 is a device that controls electric power input to the X-ray tube device 101.

  The input / output device 111 is a device used by an operator to input data related to the subject or to know data related to the subject. Specifically, it is an operation button, a liquid crystal display, a speaker that outputs sound, a touch panel, or the like. The input / output device 111 also includes a notification device that notifies the subject of the start and end of breath holding.

  The electrocardiographic data acquisition device 112 is a device that acquires electrocardiographic data of a subject. The electrocardiogram data acquisition device 112 may be a so-called electrocardiograph or a device that receives the output of the electrocardiograph.

  The operation unit 120 includes an input device 121, an image processing device 122, a display device 125, a storage device 123, and a system control device 124. The input device 121 is a device for inputting a subject's name, examination date and time, imaging conditions, and the like, specifically a keyboard, a pointing device, a touch panel, and the like. The image processing apparatus 122 is an apparatus that reconstructs a CT image by performing arithmetic processing on measurement data transmitted from the data collection apparatus 107. The display device 125 is a device that displays a CT image or the like created by the image processing device 122, and is specifically a CRT (Cathode-Ray Tube), a liquid crystal display, or the like. The storage device 123 is a device that stores data collected by the data collection device 107, image data of a CT image created by the image processing device 122, and the like, specifically, an HDD (Hard Disk Drive) or the like. The system control device 124 is a device that controls these devices, the gantry control device 108, the bed control device 109, and the X-ray control device 110. Further, the system control device 124 may execute a process flow described later.

  The X-ray tube device 101 is controlled by the X-ray controller 110 controlling the power input to the X-ray tube device 101 based on the imaging conditions input from the input device 121, particularly the X-ray tube voltage and X-ray tube current. Irradiates the subject with X-rays according to the imaging conditions. The X-ray detector 106 detects X-rays irradiated from the X-ray tube device 101 and transmitted through the subject with a number of X-ray detection elements, and measures the distribution of transmitted X-rays. The rotating disk 102 is controlled by the gantry control device 108, and rotates based on the imaging conditions input from the input device 121, particularly the rotation speed. The couch device 105 is controlled by the couch control device 109 and operates based on the imaging conditions input from the input device 121, particularly the helical pitch.

  By repeating the X-ray irradiation from the X-ray tube device 101 and the measurement of the transmitted X-ray distribution by the X-ray detector 106 along with the rotation of the rotating disk 102, projection data from various angles is acquired. The acquired projection data from various angles is transmitted to the image processing device 122. The image processing device 122 reconstructs the CT image by performing back projection processing on the transmitted projection data from various angles. The CT image obtained by the reconstruction is displayed on the display device 125.

  Note that the X-ray CT apparatus 1 may be connected to an in-hospital server or an out-of-hospital server via a network (not shown), and may read necessary data from each server in a timely manner.

  FIG. 2 is a front view of the scan gantry unit 100 of the X-ray CT apparatus 1. FIG. An example of the input / output device 111 will be described with reference to FIG. In this example, a gantry display unit 111A, which is a part of the input / output device 111, is provided above the opening 104, and a gantry operation unit 111B is provided on both sides of the gantry display unit 111A. Furthermore, a speaker that outputs sound may be provided.

  The gantry display unit 111A is a liquid crystal display, a touch panel, or the like. The gantry display unit 111A displays, for example, patient ID, name, electrocardiogram data, etc. as information related to the subject, position information of the bed apparatus 105, tilt information of the rotating disk 102, etc. . In the case of a touch panel, an operation button may be displayed.

  The gantry operation unit 111B is an operation button, and is used for setting the position of the bed apparatus 105, the inclination angle of the rotary disk 102, and the like.

  FIG. 3 is a diagram showing an example of a processing flow when the heart is imaged using the X-ray CT apparatus 1. Hereinafter, each step of FIG. 3 will be described in detail.

(Step 300)
In this step, a breath holding practice for the subject placed on the bed apparatus 105 is executed. In addition, while the breath holding exercise is performed, electrocardiographic data including an electrocardiographic waveform and a heart rate are acquired via the electrocardiographic data acquisition device 112. Details of this step will be described later with reference to FIG.

(Step 301)
In this step, photographing conditions for the main scan executed in step 302 are set. The imaging conditions may be set by the operator using the input device 121, or may be automatically set by the system control device 124 based on the electrocardiographic data acquired in step 300, or the system control device 124. The operator may appropriately change the imaging conditions automatically set by using the input device 121.

(Step 302)
In this step, the main scan is executed based on the imaging conditions set in step 301. The system control device 124 controls the X-ray control device 110, the bed control device 109, and the gantry control device 108 to execute the main scan and acquire the X-ray transmission distribution data of the subject. X-ray transmission distribution data is acquired, and ECG data of the subject is acquired via the ECG data acquisition device 112.

  Through the above processing flow, the main scan according to the electrocardiogram data of the subject is executed, and the image reconstruction based on the electrocardiogram data is further executed, so that it has a good image quality with reduced motion artifacts. An image is acquired.

  Next, details of step 300 will be described. FIG. 4 is a diagram illustrating an example of the flow of processing in step 300. Hereinafter, each step of FIG. 4 will be described in detail.

(Step 401)
The system control device 124 reads subject data from the storage device 123 or each server connected via a network. The subject data includes, for example, subject ID, name, age, sex, height, weight, disease name, normal heart rate, time of breath holding practice performed in the past, and the like.

(Step 402)
The system control device 124 displays a breath holding practice time selection icon 500 as shown in FIG. 5 on the gantry display unit 111A configured by a touch panel. The breath holding practice time selection icon 500 is a button capable of selecting a different time, for example, in 5 second steps. When the operator can predict the subject's breath holding practice time, the operator selects an appropriate time from the breath holding practice time selection icon 500. The longest time may be selected. The system control device 124 sets the value selected from the breath holding practice time selection icon 500 as the breath holding practice time.

(Step 403)
The system control device 124 notifies the subject of the start of breath holding practice through the input / output device 111 including the notification device. As a method for notifying the subject, for example, a message such as “please hold your breath” may be displayed on the gantry display unit 111A, or may be output by voice from a speaker.

(Step 404)
The system control device 124 acquires the electrocardiographic data of the subject via the electrocardiographic data acquisition device 112. The acquired electrocardiographic data is stored in the storage device 123 in association with the breath holding practice time.

(Step 405)
The system controller 124 determines whether or not the breath holding practice time has ended. The determination of whether or not the end has been made is based on, for example, whether or not the breath holding practice time set in step 402 has elapsed since the time when the breath holding practice was started. If the determination result is No, the process returns to step 404. If the determination result is Yes, the system control device 124 notifies the subject of the end of the breath holding practice. As a method of notifying the subject, for example, a message such as “Please start breathing” may be displayed on the screen of the gantry display unit 111A, or sound output from a speaker may be used. In addition, before the breath holding practice time ends, the subject may be notified while counting down the remaining time until the end time.

  With the above processing flow, it is possible to set the breath holding practice time according to each subject. That is, in the present embodiment, the operator can select and set an appropriate breath holding practice time from a plurality of options according to the subject, and the efficiency of the process related to the breath holding practice can be improved.

{Second embodiment}
A second embodiment will be described with reference to FIG. Hereinafter, only differences from the first embodiment will be described, and description of the same points as in the first embodiment will be omitted. In the present embodiment, new steps 600 and 601 are added between step 401 and step 402 of the first embodiment.

(Step 600)
The system controller 124 determines whether there is past data of the subject. The determination of whether there is past data is based on, for example, whether there is data on breath holding time when the subject has undergone cardiac imaging in the past.

  If the determination result is No, the process proceeds to step 402. If the determination result is Yes, the process proceeds to step 601.

(Step 601)
The system control device 124 reads out the breath holding time data set at the time of past cardiac imaging from the subject data, and, for example, the reference value is displayed in the reference value display unit 700 in the gantry display unit 111A as shown in FIG. Display as.

  When there are a plurality of data at the time of previous cardiac imaging, it is preferable that the data when the image with the best image quality is acquired or the latest data is read out.

  According to the present embodiment, the operator can set the breath holding time while referring to past data displayed on the reference value display unit 700, so that a more appropriate breath holding practice time can be set.

{Third embodiment}
A third embodiment will be described with reference to FIG. Hereinafter, only differences from the first embodiment will be described, and description of the same points as in the first embodiment will be omitted. In the present embodiment, step 800 is added instead of step 402 in the first embodiment.

(Step 800)
The system control device 124 calculates a recommended practice time based on the subject data read out in step 401, and sets the calculated recommended practice time as a breath holding practice time. It is known that there is a relationship between the normal heart rate, which is the heart rate during normal breathing, and the heart rate stabilization time, which is the time from the start of breath holding until the heart rate stabilizes. Therefore, in the present embodiment, the relationship between the normal heart rate and the heart rate stabilization time is stored in advance in the storage device 123 as a table as shown in FIG. The recommended practice time is calculated by comparing the normal heart rate with the table and performing interpolation. In FIG. 9, N1 to N3 are typical values of normal heart rate, T1 to T3 are average values of heart rate stabilization time corresponding to N1 to N3, and SD1 to SD2 are heart rate stability corresponding to N1 to N3. The standard deviation of time is shown. In the table of FIG. 9, by setting the heart rate stabilization time as the sum of the average value and the standard deviation, the possibility that the practice time will end before the heart rate stabilizes is reduced.

  Similarly to the second embodiment, the calculated recommended practice time may be displayed on the reference value display unit 700 on the gantry display unit 111A. The operator can set the breath holding practice time with reference to the value displayed on the reference value display unit 700.

  With the above operation, since the breath holding practice time is set based on general data, the breath holding practice time can be appropriately set even when there is no past data. A plurality of reference values can be displayed by combining the second embodiment and the present embodiment.

{Fourth embodiment}
A fourth embodiment will be described with reference to FIG. Hereinafter, only differences from the first embodiment will be described, and description of the same points as in the first embodiment will be omitted. In the present embodiment, step 1000 is executed instead of step 405 of the first embodiment.

(Step 1000)
The system controller 124 determines whether or not the heart rate is stable based on the heart rate measured in step 404.

  If the determination result is No, the process returns to step 404. If the determination result is Yes, the system control device 124 notifies the subject of the end of the breath holding practice. As a method of notifying the subject, for example, a message such as “Please start breathing” may be displayed on the screen of the gantry display unit 111A, or sound output from a speaker may be used.

  In determining whether the heart rate is stable, for example, it may be considered that the heart rate is stable if the change in the heart rate over time is within a predetermined range for a predetermined time. FIG. 11 shows an example in which the change in heart rate with time is displayed on the graph display unit 1100 in the gantry display unit 111A. In the example of FIG. 11, it is determined that the heart rate is stable in the range of Tb (s) and the heart rate is stable.

  With the above operation, the breath holding practice is completed when the subject's heart rate is stabilized, so the end of the breath holding practice is automatically set. Note that the present embodiment can be combined with the first to third embodiments.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment.

  1 X-ray CT device, 100 scan gantry unit, 101 X-ray tube device, 102 rotating disk, 103 collimator, 104 opening, 105 couch device, 106 X-ray detector, 107 data acquisition device, 108 gantry control device, 109 couch Control device, 110 X-ray control device, 111 I / O device, 111A Gantry display unit, 111B: Gantry operation unit, 112 ECG data acquisition device, 120 operation unit, 121 input device, 122 image processing device, 123 storage device, 124 System control unit, 125 display unit, 500 breath holding practice time selection icon, 700 reference value display unit, 1100 graph display unit

Claims (4)

An X-ray CT apparatus for measuring X-ray transmission distribution data of the subject together with the heart rate of the subject,
Setting means for setting the breath holding practice time, which is the time of breath holding practice performed prior to the main scan, according to the subject, and the start and end of breath holding practice based on the set breath holding practice time. An informing means for informing the subject ;
A storage means for storing a relationship between a normal heart rate that is a heart rate during normal breathing and a heart rate stabilization time that is a time from the start of breath holding to the stabilization of the heart rate;
The X-ray CT apparatus , wherein the setting means sets the breath holding practice time based on the relationship and the normal heart rate of the subject . The X-ray CT apparatus according to claim 1,
The X-ray CT apparatus , wherein the storage means stores a representative value of a normal heart rate and a sum of an average value and a standard deviation of a heart rate stabilization time corresponding to the representative value in association with each other . The X-ray CT apparatus according to claim 1 ,
The X-ray CT apparatus , wherein the informing means displays the set breath holding time as a reference value . The X-ray CT apparatus according to claim 3,
The X-ray CT apparatus characterized in that the notification means displays the past breath holding practice time as a reference value when there is a past breath holding practice time of the subject.

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