CN102038515A - X-ray computed tomography device - Google Patents

Abstract

The invention provides an X-ray computed tomography device. The device has the function of stopping pre-scanning according to the time at which the concentration of the contrast medium in the region of interest (ROI) of the monitored object reaches the predetermined value by pre-scanning the concentration and the function of beginning main scanning. The main scanning conditions are initially set according to the physiological phenomenon which is measured before the contrast medium injection, of the object. Whether the main scanning conditions which are initially set need to be reset is judged according to the variation of the physiological phenomenon measured before finishing pre-scanning. If the main scanning conditions need to be reset through judgment, the main scanning conditions are reset as the main scanning conditions corresponding to the physiological phenomenon measured before finishing pre-scanning from the main scanning conditions which are initially set.

Description

X-ray computed tomography apparatus

Technical Field

The invention relates to an X-ray computer tomography device which is provided with a device for carrying out X-ray computer tomography

The main scanning is preceded by a pre-scanning.

Background

In contrast-medium imaging, in injection into the object to be examined

It is very important to start scanning (main scanning) when the contrast agent flows into the relevant area. Thus, sweeping

The scanning (pre-scanning) is performed before the main scanning. To suppress x-ray dose, pre-scan

Is performed using less than all of the X-rays used in the main scan

For projection data acquired in a pre-scan for real-time reconstruction processing. Reconstructed in real time

The image (tomographic image) is immediately displayed. Visual inspection of the image by an image technician

The concentration of contrast agent (degree of staining) in the relevant area. Contrast agent in judgment-related region

When the concentration reaches the predetermined concentration, the graph gallium technician presses the trigger button of the main scan.

When in contact: when the send button is pressed, the pre-scanning is stopped, and the preparation (setting) of the main scanning is started. Master and slave

Preparation for scanning involves moving the couch roll (couch) to the top of the previously determined scanning range

The shaft is accelerated to a preset speed, the rotating frame is accelerated to a preset scanning speed,

heating the filament, etc. Once the preparation work for the main scan is finished, the main scan starts.

A technique called the bolus tracking method was developed in

In this technique, the image technician presses the following: the operation of the send button is automatic. Tracking in field

In the method, CT values or averages of relevant regions are extracted from an image obtained by pre-scanning

When the CT value or the average value of the relevant area exceeds the threshold value

Then, the pre-scanning is stopped, and the main scanning is started.

In an x-ray computed tomography apparatus, the recording is performed in synchronization with an electrocardiogram recording wave

Line scanning one or more series of conventional ECG gated scans (gates) are acquired at specific time phases

scan) schemes are known. According to this solution, in order to reduce the occurrence of motion due to the heart

Motion artifacts, time required for one rotation of the X-ray tube (scan speed) and heart

The dynamic cycle is sufficiently short.

In order to maintain high diagnostic values by reducing motion artifacts to a certain extent, a sweep is performed

The seek speed needs to be short enough, for example, 500 milliseconds. Conditions to achieve a scan speed of 0.2 seconds

It is not easy.

As a means of reducing motion in more popular devices whose scanning speed is 1 or 0.5 seconds

Artifact technique, the development of a technique known as ECG gated reconstruction (segment scan)

scan)) of the same. In such a segment scan, an electrocardiogram is acquired simultaneously with the acquisition of the technical data

Number collect. By root-grafting electrocardiographic data, specific data is extracted from a set of collect projections in each cardiac cycle

Data (segment) in a partial period centered on the cardiac temporal phase. From multiple cardiac cycles

The extracted segments are connected to each other to prepare 3600 projection data required for image reconstruction.

In a segment scan, the number of segments to be acquired is often set at the top. Time width over segment

The degree decreases, the number of segments to be acquired increases, and the temporal resolution of the image increases. I.e. different

Unlike this, the number of image gallium in the cardiac time phase increases, along the time width of the segment

The larger the number of stages to be acquired, the smaller the number of stages to be acquired, the lower the time fraction of the score. If the segment is acquired

The number cannot reach the predetermined number, the predetermined time resolution cannot be obtained

The image of (2). In order to acquire an image having a predetermined time resolution, at least acquisition correspondence is required

Projection data of a heart rate, which corresponds to the top determined number of segments.

The segment scan is susceptible to motion artifacts, and thus, the scan is ill-conditioned

Performed while the person holds his breath. The length of time that a patient can hold his breath is limited. In a section

In the scanning, the required corresponding heart rate must be acquired within a limited breath-hold period

In a segment scan, therefore, the heart rate of the object to be examined has to be quantified beforehand,

and the scan speed must be adjusted according to the heart rate, i.e. when it is required for the X-ray tube to rotate once

And (3) removing the solvent.

As described above, in the bolus fiduciary method, the pre-scan is performed before the main scan.

When a silent scanning scheme is applied to the main scanning, a scanning speed timing and a main scanning start timing are set

The time difference therebetween becomes long. Thus, the heart rate in the main scan may be relative to the set scan speed

Heart rate at degrees varies greatly. Therefore, in some cases, the scanning speed in the main scanning

This problem becomes more pronounced in contrast agent examinations.

This is because the heart rate often varies greatly due to injection of contrast media.

Disclosure of Invention

It is an object of the invention to allow a change in physiological phenomena for a subject to be examined to pass through X

Resetting scan lines by using bolus tracking method as main scan for ray computer tomography apparatus

And (3) a component.

According to a first aspect of the present invention, there is provided an x-ray computed tomography clamp apparatus

Device for performing a top-scan to obtain injected contrast using a weaker X-ray

Data of the object of the agent, and by using X-ray mixtures after the prescan

Scanning to acquire data of an object, the apparatus comprising:

a judging unit, which is named as the unit based on the contrast agent injection at the beginning or the pre-scanning and pre-scanning

The number collect of physiological phenomena of the subject measured in the period between the end of the scan is used to determine whether or not there is a need to perform the scan

The scanning condition of the main scanning is reset, which is initially based on the injection of contrast medium

Data of a measured physiological phenomenon of a subject; a scanning condition setting unit which is set

Configured to scan the main scan when the judging means judges that it is necessary to reset the scanning condition

The conditions are reset from the initially set scanning conditions to correspond to the injection of contrast agent or pre-treatment at the beginning

Scanning and at the top: scanning of data of a physiological phenomenon of a subject measured during a period between scan ends

And (4) conditions.

According to a second aspect of the present invention, there is provided an X-ray computed tomography radiography apparatus

Device for performing a top-of-line scan using a comparative X-ray to obtain an injected contrast

Data of an object of the agent, and performing a main scan by using a stronger than light X-ray after the pre-scan

The device comprises a scan condition setting unit which is matched with the scanning condition setting unit

Rooted collect at the beginning of contrast injection or pre-scan; measurement in time period between end of pre-scan

Sets the sweep finger condition of the main scan.

According to a third aspect of the present invention, there is provided an X-ray computerized tomography radiography system

The device performs the top stop by using a relatively weak X-ray: scanning to obtain wand injected contrast

Data of an object of the agent, and performing a main scan by using a weaker X-ray after the pre-scan

Drawing numbers collect of the object, the device including a display unit configured to display the numbers collect

The inter-map and numerical values show data of physiological phenomena of the subject, and also show sweeps related to the main scan

Finding a conditional elm entering area; an elm-in unit configured to be used for elm-in an elm-in area

Scanning conditions in the main scanning; and a scanning condition setting unit which are mutually root

According to the input sweep during the period between the start of contrast agent injection or pre-scan and the end of pre-scan

The scanning conditions set scanning conditions of the main scanning.

Drawings

Other day labels and advantages of the invention will be described later; the foregoing is illustrated and partially described

From the description herein, a celebration can be obtained, or a practice of the invention can be learned

The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings, description, and claims included in and forming a part of this specification

There has been shown a presently preferred embodiment of the invention and associated with the description of a drum provided above and provided below

Taken together, the detailed description of the preferred embodiments serve to explain the principles of the invention.

FIG. 1 is a schematic view showing an X-ray computed tomography image according to an embodiment of the present invention

A block diagram of the structure of the main part of the apparatus;

FIG. 2 is a table showing the data stored in the data lender of FIG. 1 (Heart Rate/egg-case distance/Scan)

Speed);

FIG. 3 is a flowchart showing the procedure of the blob fiduciary method in this embodiment;

FIG. 4 is a time diagram of the field tracking method of FIG. 3;

FIG. 5 is a congratulatory graph which additionally illustrates the step soils 56 and 57 of FIG. 3;

FIG. 6 is a view supplementary to the description of steps 56, S1O, and S11 in FIG. 3;

FIG. 7 is a view showing a state where the initially set main scanning condition in this embodiment is captured

A view showing an example of a window;

FIG. 8 is a view showing a display window when the main scanning condition decision in this embodiment is reset

A view of an example of (a);

FIG. 9 is a process for showing a field tracking method according to a first modification of this embodiment

A flow chart of (1);

FIG. 10 is a process showing a blob tracking method according to a second modification of this embodiment

A flow chart of (1);

jail 11 is a procedure showing a blob tracking method according to a third modification of this embodiment

A flow chart of (1); and

fig. 12 is a view showing an example of a display window in the third modification of this embodiment.

Detailed Description

X according to a preferred embodiment of the present invention will be described below with reference to the several views of the drawings

A computed tomography apparatus. Note that the x-ray computed tomography projection apparatus includes

Of the type, e.g. of the rotary/swivel type, in which the X-rays

The tube and the X-ray detector are rotated together around the object to be examined; stationary/rotary type device

In this device, a plurality of detecting elements are arranged in the form of a ring and only X

The ray tube rotates around the object to be examined. The invention can be applied to any type

In the example, the current mainstream type — spin/spin type one will be described as an example.

Further, the image reconstruction method includes a 3600 method which requires a method corresponding to the surrounding object

3600 projection data of one revolution of an object under examination, and a half-scan method, which method is to

And (l 800 + fan angle) projection data is obtained. The present invention can be applied to these methods

Either method. In this example, the method 3600 will be described as an example.

As a mechanism for converting incident x-rays into electric charges, the following technique is a mainstream technique

The operation is as follows: indirect conversion type of irradiating X-rays by a fluorescent substance such as a flash

The line is converted into light and the light is converted into electricity by a photoelectric conversion element such as a photodiode

Loading; and a direct conversion type of generating an electron hole in a semiconductor by X-rays

(electron-hole) pairs and moves the electron hole pairs to the electrodes, i.e., a photoconductive phenomenon. As

An X-ray detection element, either of which may be used, in this example, the element will be

The former type, i.e., the indirect spin-clamp type, is explained as an example.

Recently, with the installation of multiple pairs of X-ray tubes and X-ray detectors on the rotating ring

The development of commercialization of the so-called multi-tube type X-ray CT apparatus has developed related techniques

And (4) performing the operation. The present invention can be applied to a conventional single tube type X-ray CT apparatus and a multi-tube type

In this example, a single tube type X-ray CT apparatus will be exemplified

And (6) describing the line.

In addition, the X-ray computer tomography apparatus uses a single-chip type of X-ray detection,

the detector has a single detector element array having a plurality of detector elements arranged along a channel direction

X-ray detecting elements, or X-ray detectors of the multi-slice type having a plurality of

An array of individual detector elements, the arrays being juxtaposed in the direction of the slice. The present invention can use this

Any of these types. In this example, the former type, i.e., the one-piece type

An X-ray detector is illustrated as an example.

FIG. 1 shows the main components of the X-ray computed tomography apparatus according to this embodiment

Partial structure. A gantry 5 encloses the X-ray tube and the X-ray detector, the X-ray tube and the X-ray detector

The radiation detectors are mounted together on a rotating cabinet shaped like a ring. The X-ray tube passing through

The imaging space is opposed to X-ray detection. The object to be examined, which is located on the couch roll 7, is placed on

In the popular space of the gantry 5. The photovoltaic tax 7 moves in its longitudinal direction. On the basis of the principle of the object

The body axis is almost parallel to the longitudinal axis of the subvolume 7 and to the axis of rotation of the X-ray tube. Parallel to the X-ray

The direction of the rotation axis of the line tube is called the sheet direction, a high voltage generating unit applies a tube voltage, and

a filament current is provided to the X-ray tube to generate X-rays. X village line on-phase through object transmission

Electric charges are generated in the corresponding X-ray detection element. These charges are extracted as a current signal. This is achieved by

The current signal is converted into a voltage signal by a Data Acquisition System (DAS). The signal is amplified and

converted into a digital signal. The digital signal is used as projection data and heart through slip ring and top-processed

The electrogram data is stored together in memory. Image reconstruction unit based on 3600 projection data reconstruction

And building the national residue data. The image reconstruction unit comprises an ECG gate reconstruction function, according to the ECG gate

A reconstruction function, data (segments) in partial periods around a particular cardiac temporal phase are derived

Electrocardiographic data is cut from the projection data set in each cardiac cycle. From multiple cardiac cycles

The cut segments are connected to each other, thereby preparing 3600 projection data required for image reconstruction.

Reconstruction of the number of images corresponding to the temporal phase of the heart to be determined from the prepared 3600 projection data

Collect, the number of reconstructed images collect is displayed on the display 8 by the display controller 10.

The physiological phenomenon amount device 4 measures a physiological phenomenon of the subject. The physiological phenomena include heart

Beats (movement of the heart), breathing, etc. In this example, the physiological phenomenon will be described as <3

Jump ". Electrocardiography 4 detects an electrical phenomenon of the heart by electrified education connected to a subject, and

an electrocardiographic fixed number collect showing the change of the electromotive force with time, a physiological monitoring unit

2 is connected to an electrocardiograph 4. the physiological phenomenon monitoring unit 2 is provided with an electrocardiographic data meter

The number of heartbeats per minute, i.e. heart rate, is calculated. The physiological image monitoring unit 2 also calculates

Heart Rate check the heart rate at the current time point relative to the specific time point, i.e., when the main sweep is initially set

Whether the change in the heart rate at the time point when the heart rate referenced in the condition is measured exceeds a predetermined level

And (4) determining the value. 184 the physiological phenomenon monitoring unit 2 will monitor the heart rate if the heart rate variation exceeds a predetermined value

A signal for prompting reset of the main scanning condition is outputted to the main scanning unit together with a signal representing the heart rate

A scanning condition selection unit 1. Namely, the physiological phenomenon monitoring unit 2 performs heart rate examination of collect subjects

Whether it is necessary to reset the main scanning conditions. Note that the change in heart rate is as the current heart rate

And the difference between the heart rates quoted when the main-scan condition was initially set before injection of contrast agent or

Rate of change.

Upon receiving a signal prompting the resetting of the scanning condition from the physiological phenomenon monitoring unit 2

The scanning condition selecting unit 1 judges the most dwelling with respect to the heart rate received together with the signal

Or substantially optimal scanning conditions. In practice, the scanning condition selecting unit 1 writes from scratch

Such as a semiconductor memory, a magnetic disk or a magneto-optical disk owned by the data memory 6

The scan condition corresponding to the heart rate is selected from a table in the storage medium.

As shown in FIG. 2, for example, in this table, a plurality of Heart Rate (HR) -related ones are set

Multiple sections, multiple pitch (HP) and scan speed associated with these sections

And (4) connecting. Referring to fig. 2, in the table, the relative Heart Rate (HR) is set for different distances and scan speeds

Different parts of (a). However, the' rate may be divided into several segments within the same portion. The distance between the two bone-knitting bones

The scan condition used in a rotational scan can be defined as the scan condition that is applied when the x-ray tube rotates once

The distance (in mm) traveled by the drops 7. The scan speed may be defined as one revolution of the X-ray tube

The time (seconds) required.

In the table, higher scan speeds are associated with higher heart rates and vice versa.

Furthermore, in the table, a longer pitch is associated with a higher heart rate and vice versa. Tong (Chinese character of 'tong')

With such an association, the main-scan condition can be reset so as to, in advance: time of first determination

The main scan (rotational scan) is completed within the predetermined scan 1 range, and is kept at the ECG gate

The number of segments required in the reconstruction method and prevents an excessive reduction of the temporal resolution.

Note that the scanning conditions include a scanning range in addition to the distance and the scanning 1 speed, and may be

Reconstruction at the ECG gate with maximum scan time for breath hold (upper limit of finger sweep time)

Number of segments of the heart, and particular cardiac time phase (delay from R wave in electrocardiogram jail)

Late time), tube voltage, tube current, fragmentation, etc. In the case of these scanning conditions, it is preferred that,

the pitch and scan speed are heart rate sensitive. For example, if the heart beat is mild to slow, 160 heart rate decreases,

the number of segments required for ECG gated reconstruction cannot be prepared unless the scan speed is reduced or the distance is reduced

Catalpa and low in content. On the other hand, if the scan speed and distance are excessively low, then in terms of scan time

And Ili obtain the projection data of the top carbon fix over the entire scan 1. On the contrary, hold by heart

Mild, then heart rate increases, and the ECG gate reconstruction can be prepared for short scan times

Even if the scan speed and the pitch of the bone are increased. Predetermined

And (5) shadow data of a scanning range. The excessive increase of the scanning speed and the egg-case distance is divided into time

The improvement in rate reserves space. In the above table, distances and sweeps are determined positively with respect to heart rate

Speed is traced to level the street.

Referring back to fig. 1 again, the main scanning condition selected by the scanning condition selection unit 1

The data choice of (3) is provided to the scan control. The scan controller 3 provides scan conditions according to the scan conditions

The rotational speed of the X-ray tube and the moving speed of the couch 7 are controlled. For example, scan control' 3

Controlling the rotating frame driving unit of the gantry 5 so that the rotating frame reaches within a predetermined time

To the set scanning speed and maintain that speed. Then, scanning, drawing, and 3 drawing high voltage generator

A unit to start heating the filament of the X-ray tube for a predetermined period of time

Reaching a temperature corresponding to the daughter tube current condition. The scan 1 controller 3 also controls the X-ray stop sheet

And (c) adjusting the opening according to the fragment thickness condition. The scan controller 3 further controls the socket

Scarlet unit to reach speed corresponding to pitch in predetermined time period to start

The couch roll is moved.

Fig. 3 shows the procedure of the blob tracking method in this embodiment. FIG. 4 is a field heel

The time of operation a good night's sleep is tracked. Device 4 for measuring physiological phenomena as preparatory pinching for field tracking pinching

The measurement of the electrocardiogram is started (S1). This measurement is continued until the contrast agent is injected and

the main scan is completed after the top scan is completed in sequence.

In the pre-scan, the silhouette data of the object is continuously obtained by using relatively weak X-rays

Obtained from the earth, CT values of voxels in the ROI or representing the concentration of contrast agent in the ROI

Is monitored during the main scan, the projected number of objects collect at the top of the scan

And then acquired by using comparative X-rays.

The electrocardiograph 4 calculates the heart rate from the measured electrocardiogram and the main scanning conditions are the fade

Set according to the heart rate. Whereas, in the real residue, the heart rate is slightly different. Therefore, it is preferable that, in the case of,

the heart rate being a predetermined time width, e.g. flat within five seconds immediately preceding the setting operation

Mean, or median within a time horizon determined by pre-carbon, and on the basis of this mean or median

The value sets the main scanning condition. For convenience of description, it is assumed that the main scanning condition is set according to the heart rate

In (1). The calculation is displayed on the display 8 together with the electrocardiogram data by the display controller 10

Heart rate of.

The operator can make a choice by referring to the displayed electrocardio bin and heart stroke as a choice unit 9 so as to facilitate the selection of the heart stroke

A drive pre-scan condition, a main-scan condition, and a program for performing a main-scan: resetting of conditions

The reset condition (S2). Note that the specified values are almost many items of the prescan condition

The purpose is determined. That is, the following is set: a lower tube voltage and tube current are set than with the hinge,

to suppress x-ray irradiation to a minimum, slice pets, a high scanning speed for increasing time resolution

Rate, and a small number of reconstruction matrices to improve substantivity, in addition, prescan finger position, contrast agent

Concentration monitoring area, conditions for transition from pre-scan to main scan (threshold for contrast agent concentration),

etc. are manually set.

In addition, many items of the main scanning condition, for example, tube voltage, tube current, segment

Degree, reconstruction moment, and idiomatic field of view (FOV), almost according to the object, subject of examination

Sex and build, etc. Scanning range obtained by the number of spin-scan executions collect

The enclosure is set, for example, to the extent that the sundial covers the entire area of the heart. In addition, each patient can

The upper limit of breath-holding time is unique and the ECG gate reconstruction method is set

Required minimum number of stages distance (HP) "and speed" is selected by scan conditions

The element 1 is set to a value corresponding to the heart rate by reference to a table in the data store 6. Or,

these items were manually entered by a vulgar technician.

The reset condition for performing the reset of the main scanning condition represents a rule,

the rule states that classes are present when the heart rate in front of the main sweep, i.e. the pre-scan, ends or in the real domain

Similar heart rate at time point, the initial setting of the main from the preliminary phase of the bolus tracking method described above

When the heart rate under the scanning condition changes to a certain degree, the initially set main scanning condition should be heavy

A main scan condition corresponding to the heart rate at the end of the top scan is newly set.

For example, if the heart rate at the original setting is '60' in the table shown in FIG. 2,

this stroke is included in the 0-70 "portion of the table. Thus, a pitch is provided in this portion

HP' o.9 ". However, if at the top: heart rate measured at the end of the scan Z540-70

Outside the section, the pitch HP corresponding to this heart rate should be set. On the other hand, due to note

The heart rate, which is changed by the contrast agent, may recover its normal value after a certain time.

I.e. even if the heart rate is at pre: the variation at the end of the scan is large and may thereafter also tend to be stable and be at

The normal value is restored at the time of main scanning. In some cases, the heart rate may remain a variable value,

without restoring its normal value. The heart rate variation is different between different people. Therefore, doctors and nurses

The birth or birth technician should check-at the time of the main scan-whether the heart rate has returned to a normal value.

This determination is reflected in the reset condition. The doctor or imaging technician may optionally

Setting the heart rate when the portion corresponding to the heart rate immediately before the main scan corresponds to the initially set heart rate

Whether to reset the main scanning condition when moving a certain number of stages (step).

When the elm pinching unit 9 is pressed at time T2 after the first setting is finished

Is activated, contrast agent is automatically injected from the injection unit into the patient. In the course of injection

Performing a pre-scan beginning after the time required for the contrast agent to reach the monitoring location

(S3) that is, at high speed of the X-ray tube and X-ray detector relative to the positioned segment

Continuously generating small doses of x-rays while continuously rotating around the object, thereby fixedly acquiring

And (6) fetching data. Together with the pre-scan, the figure protection reconstruction unit reconstructs figure-colloquial data from the technical shadow data in real time

(S2). CT value bins in the relevant regions set in advance are extracted from the image data. This value

Or the average of the CT values of a plurality of pixels of the region of interest with a threshold value for shifting to the main scan

And (4) the ratio. The CT value or the average of the CT values represents the concentration of the contrast agent in the relevant region.

The physiological phenomenon measuring device 4 continues the heart rate of the child during this pre-scan. As shown in figure 7 of the drawings,

the heart rate is displayed as a time chart and as a numerical value (S4).

As shown in FIG. 7, the reference heart rate and the current heart rate are taught when the scanning condition is set at the beginning

Are displayed together. The initially set scanning speed and distance are also displayed numerically. Emergency stop button

Together with these pieces of information. The heart rate of the subject to be examined may be due to injection of contrast agent

And the like, to change abruptly. In such a case, the skilled person can be familiar with

The emergency stop of the pre-scan and the main scan is performed by clicking the emergency stop button.

Min value when CT value reaches a transition cut the throat main-broom or manually pressed by an image technician

When the main scan transition triggers the trick button (T3), the pre-scan is terminated (S5). Physiological phenomenon monitoring unit 2

The heart of the quantity at the end of this scan is checked for a short period of time before time T4

Whether the rate change satisfies a reset condition for performing the main scanning condition reset (S6). That is to say that the first and second electrodes,

deciding a heart rate when the pre-scan condition is initially set and a heart rate measured at the end of the pre-scan

The difference between is compared to a threshold for resetting the condition.

If the absolute value of this difference does not reach the reset condition threshold, l6q judges the heart rate change

Whether or not the change is small enough not to satisfy the resetting condition and the physiological phenomenon monitoring unit 2 does not sweep toward

The finger condition selection unit 1 sends a signal for prompting to reset the vertical scanning condition. Through which

By doing so, as shown in FIG. 5, scanbar equal selects cell 1 to send an initial transmission to scan controller 3

Set main scanning conditions or main scanning bars that instruct the scan controller 3 to set at the beginning

And starting setting under the part. Then, the scan controller 3 sets the main scanning condition at the beginning of the transmission

Next, the setting of the main scanning is started at time T4 (S7). The scan controller 3 at time T5

The setting is previously completed, and the main wiping is started at time T5 (S8). When completely scanning the range from the whole

Upon acquiring the data, the scan control 3 terminates the main scan at time T6 (S9).

If it is determined in step 56 that the heart rate sum quoted at the time of initial setting of the scanning conditions is equal to

The absolute value of the difference between the measured cardiac leathers at the end of the pre-scan reaches the threshold of the reset condition

Value | e4 determines that the change in heart rate is so large that the reset condition has been met. Then, the physiological phenomenon monitor

The viewing unit 2 sends a prompt to the scanning condition selection unit 1 to reset the main scan

The condition is signaled and at the same time the heart rate measured at the end of the pre-sweep is sent, by this exercise,

as shown in fig. 6, the scanning-condition selecting unit 1 selects by referring to a table in the data storage 6

Selecting a distance and a scanning speed corresponding to the heart rate at the end of the pre-scanning, and selecting the main scanning condition from

Resetting the original egg-case pitch and scanning speed to the selected pitch and scanning speed

(S1O)。

When the distance and sweep speed decision is reset, the display control 10 is compared to that originally set

The pitch and scan speed together show the reset pitch and scan speed as shown in fig. 8.

The image technician can recognize the reset distance and scanning speed according to whether the reset distance and scanning speed are displayed

Whether the distance and the scanning speed are reset.

When performing ECG gate scan, the scan condition selection unit 1 selects the scan condition by connecting the pre-scan

Cardiac cycle (reciprocal of heart rate) at invitation times time from R-wave to specific time phase

Width to cardiac cycle ratio at a time phase (specific time phase) associated with the setup

The delay time from the R wave to a specific time phase is newly calculated ".

According to the above description, whether or not it is necessary to reset the main scanning condition is based on the initial setting

The difference between the heart rate under the main scanning condition and the heart rate at the end of the pre-scanning is judged, and the main scanning is performed

The scanning condition is reset according to the heart rate at the end of the pre-scan. However, the invention is not limited thereto

The heart rate at the end of the pre-scan, whether it is necessary to reset the initially set scan conditions, may be

According to any given time from the beginning of contrast agent injection or pre-scanning to the end of the pre-scanning

Heart rate measured at the point. Further, the main scanning condition may be based on the time period

The heart rate measured at any given point in time is reset. Whether or not it is necessary to reset the main scanning

Provided that the heart rate is dependent on the heart rate at the end of the pre-scan, i.e. closest to the point in time when the main scan starts

In addition, by resetting the main scanning condition, the main scanning condition can be approximated to

And the optimal main scanning condition corresponds to the actual heart rate when the main scanning is executed. Or whether it is necessary

Resetting the initially set scanning conditions may be based on any given point in time within this period

The measured heart rate is used to make a decision and then the main scanning conditions are reset. Even in the case of the present example,

the main scanning condition may be performed under a main scanning condition that is set initially before injecting the contrast agent

The main scanning is closer to the optimum value.

The scanning condition selection unit 1 sends the reset main scanning to the scanning controller 3

And (4) conditions. By this operation, the scan controller 3 sets the stage according to the reset main scanning condition

A frame 5 and a couch roll 7 (S11). After the setting is completed, main scanning is performed by X-ray irradiation

(S8、59)。

As described above, when the heart rate changes, the main scanning condition, more specifically, the spiral

The distance and scan speed are reset to account for the number of segments required for ECG gate reconstruction, for example

Can be completely prepared and acquired within the entire planned scan range within the upper limit of the scan time

Projection data, and the like. Furthermore, this may improve the temporal resolution.

If step soil 56 in FIG. 9 determines that the heart rate change is large enough, the reset has been met

Set conditions, P | 4 display controller 10 may cause display 8 to display the heart rate and a reminder

To confirm the main scanning condition reset and reset the continue/stop button, thereby

Finally, it is confirmed whether it is necessary to perform the main scanning resetting operation (Sl 6). If not commanded

The resetting is performed (Sl7) and the setting of the table frame 5 and the couch roll 7 is performed according to step 57

Starts under the first set main scanning condition, and main scanning is performed under this condition (S8, 59).

If the command performs reset (Sl7), and reset the main scan stripes in step S1O

The condition setting rack 5 and the saddle 7 are held by the socks (S11).

Because the operator can judge whether the resetting is necessary after the pre-scanning is finished,

thus, even temporarily, a heart beat occurs in a very short period of time near the end of the pre-scan

The adverse effect of resetting the main scanning condition can also be avoided at negligibly small events.

If the heart rate varies excessively, i.e. very rare situations occur, e.g. heart rate variability

Three or five levels in the table are quantified and the main scan is preferably stopped in some cases. To process

In such a case, when the physiological phenomenon monitoring unit 2 judges that the heart rate has changed by a predetermined level

For example, in case of three or five stages on the table, the scanning condition selecting unit 1 may display the display 8

Displaying a message to recognize the main scanning stop and main scanning continuation/stop buttons, and displaying

A significantly varying heart rate (Sl 2). If the operator (image technician) commands continuation of the main scan

(Sl3), master with I $4 reset at pace dishes S1O and S11 according to the significantly changed heart rate

The main sweep is performed under the sweep condition. If the operator commands to stop the main scan (Sl3), then step

The tight shift to main scanning in soil Sl4 is performed by a system controller or an interlock circuit (not shown)

And (4) stopping suddenly.

Alternatively, as shown in fig. 11, the main scanning condition may be manually reset. As shown in fig. 12

As shown, display control 10 operates on a time chart, numerical values, and values associated with the main scanning conditions

In the region of the input, the sum of the soil distances initially set is displayed

Scanning speed, displaying a plurality of candidate egg-case distance sums on a pull-down menu connected to corresponding areas

A plurality of candidate scan speeds. In addition, the scanning range, which satisfies the main scanning, can be predetermined

Distance ■ under the condition that the main scanning is completed within a predetermined scanning range within a time period

Limit, the maximum period of time that the subject can hold his breath, i.e., the upper limit of the main-scan time is displayed

Shown in the figure. The technician can insert the elm into the elm and insert the unit 9 through the reference scan range and distance

Limit, upper limit of main scan time, and heart rate, selecting pitch and scan from corresponding candidates

Speed, thereby resetting the pitch and scan speeds (Sl5) — if at the selected pitch and scan

Under the condition of scanning speed, the scanning speed is not within a predetermined scanning range within a predetermined time period

If the main scanning is completed or the necessary rank cannot be prepared, the display control field 10 judges the situation

And refusing to reset the entered scanning condition once the selection is performed. Display control

The device 10 also displays a message on the display 8 to prompt a re-selection of the pitch and scan speed

And (4) degree.

Other advantages and modifications will readily occur to those skilled in the art. Due to the fact that

Accordingly, the invention in its broader aspects is not limited to the specific details shown and described herein

And representative examples. Accordingly, it is intended that all such modifications and variations not departing from the spirit and scope of the appended claims and their equivalents

Various modifications may be made without deviating from the spirit and scope of the general inventive concept as defined by the claims.

Claims (9)

1. An x-ray computer tomography projection apparatus using weaker x than x

A pre-scan is performed with the radiation to acquire data of the object injected with contrast agent, and is performed during the pre-scan

Thereafter, a main scan is performed by using relatively strong X-rays to acquire data of the object, and the apparatus

The method comprises the following steps:

a judging unit configured to start injection of contrast agent or pre-scanning and

data of physiological phenomena of the subject measured in the period between the end of the pre-scan is used to determine whether there is any

It is necessary to reset the scanning condition of the main scanning, which is originally based on the contrast medium being injected

Data set of previously measured physiological phenomena of the subject; and

a scanning condition setting unit configured to set a scanning condition when the judging unit judges that it is necessary to repeat

When the scanning condition is newly set, the scanning condition of the main scanning is reset from the initially set scanning condition

Arranged to correspond to the period between the start of injection of contrast agent or pre-scan and the end of pre-scan

Scanning conditions of data of a measured physiological phenomenon of a subject.

2. The apparatus according to claim 1, wherein the judging unit judges that the duplication is not required

When the scanning condition is newly set, the scanning condition setting unit holds the scanning condition that was originally set.

3. The apparatus according to claim 1, wherein the scanning condition setting unit sets the scanning condition according to the scanning condition

The data of the physiological phenomenon measured at the end of the pre-scan resets the scan conditions.

4. The apparatus of claim 1, wherein the scan condition setting unit comprises a memory

A memory configured to store a table in which a plurality of scan conditions are associated with

And relates to the multi-level association of physiological phenomena.

5. The device according to claim 1, wherein the judging unit is based on the time at which the injection is started

Contrast agent or the physiological phenomenon measured during the period between the pre-scan and the end of the pre-scan relative to the physiological phenomenon measured during the period between the pre-scan and the end of the contrast agent

The degree of change in the physiological phenomenon of the subject measured before the injection of the contrast medium, the reset sweep is judged

The necessity of the drawing conditions.

6. The apparatus of claim 1, wherein the physiological phenomenon measuring device measures pairs

Like the heart rate.

7. The apparatus of claim 1, wherein the determining unit determines the scan mode according to the scan mode at the pre-scan junction

The data of the physiological phenomenon measured at the time of invitation judge the necessity of resetting the scanning condition.

8. The apparatus of claim 7, wherein the scan condition setting unit sets the scan condition according to the scan condition

The data of the physiological phenomenon measured at the end of the pre-scan resets the scan conditions.

The apparatus according to claim 6, wherein the judging unit determines in advance according to the determination

The average or median of the heart rate over the time span of (a) determines the necessity to reset the scanning conditions.

9. The apparatus according to claim 9, wherein the determining unit is based on an average of heart rates

The value or median resets the scanning conditions.

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