JPS58206724A - Pulse cooperated x-ray ct apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention belongs to the technical field of CT apparatus, and is particularly applicable to the CT apparatus for CT apparatuses, and in particular, CT apparatuses for detecting CT scans of parts to be examined that undergo periodic body movements, such as the heart.
This invention relates to a CT device that can obtain r@.

[Technical background of the invention and its problems]

In a conventional CT device, such as a heartbeat-linked
MCT*4-4 was obtained as follows. That is, as shown in US Pat. No. 4,182,311, the X-ray tube is intermittently rotated around the body axis of the subject, for example, PA, while rotating at a constant rotation angle of s f9 +, for example, 0.
A large amount of projection data is obtained by irradiating X*+ every 6 degrees.

Collect patient electrocardiogram data simultaneously. After completing multiple scans, the projection data at the same phase of each heartbeat is selected from among all the obtained glodijection data, the selected projection data is rearranged as projection data at a predetermined rotation angle, and the projection data is For rotation angles without data, W
An X@CT image of the heart was obtained by supplementing projection data of four tangent rotation angles by interpolation and reconstructing the resulting projection data of 660/number of rotation angles.

However, the X 1Hij CT image obtained by the heart rate-linked Xll1 ICT device shows whether the patient is holding his breath during multiple scans (the required time is, for example, about 20 seconds).
This is obtained on the premise that the chest is not displaced by keeping the exhalation shallow so as not to move the chest. During imaging with a heart rate-linked X-ray CR device, if the patient
When a person inhales or changes their body position, the position of the heart changes, causing artifacts in the re-created X-ray CT image and poor spatial resolution.

[Purpose of the invention]

This invention was made in view of the above circumstances, and
To obtain an X-ray crIH without causing arch-eye accommodations and without deteriorating spatial resolution even if the patient takes a deep breath or changes his/her body position during an X-ray scan to obtain the cr@-ray. The object of the present invention is to provide a heart rate-linked xHcr device that can perform the following functions.

[Summary of the invention]

The outline of the present invention for achieving the above object is to obtain a projection booter by intermittently irradiating X-rays while rotating around the subject, and at the same time detect the electrocardiogram signal of the subject. Reconstructing all the projection data of a specific phase based on the signal
In a heart rate-linked X-ray CT device that displays T, it detects the subject's electrocardiogram gi and bioimpedance, detects R#L from the electrocardiogram signal, and detects the R-wave synchronization signal and bioimpedance synchronized with this. an electrocardiogram respiratory monitor that outputs a body movement deep breathing detection signal that detects the displacement of the specimen;
An auxiliary storage device that stores projection data temporally associated with the MJ record R wave synchronization signal and the body movement deep breathing detection signal and each glogejection data; the projection data is read from the auxiliary storage device, and the body movement deep breathing signal is detected. The present invention is characterized by comprising an arithmetic processing unit that selects projection data of a specific heartbeat phase from other projection data excluding the projection data at the detected timing and reconstructs an ll1li image.

[Embodiments of the invention]

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

The heart rate linked wJ X-ray CT apparatus according to the present invention is configured as shown in FIG. In the same figure, 1 indicates an arithmetic control 1141Fa, which starts the operation of various parts of the device described later when the operator operates an operation console (not shown), and outputs a start control signal 2 to control the operation. After inputting the data 8 and the valley data such as the electrocardiogram signal 11 and associating them temporally, the associated data is output as scan data to the auxiliary storage device 16, which will be described later. Read out the more important scan data and rearrange it, Xg
It is configured to reconstruct a CT image.

Reference numeral 6 indicates a mount, which is equipped with an X-ray source 5, and
In response to the start control signal 2, the X-ray source 5 is configured to rotate around the subject 7 by a constant rotation angle, for example, 0.6 degrees, at constant time intervals. 4 is an X-ray generation control device, which receives the start control signal 2 and applies a high voltage to the X-ray source 5 at fixed time intervals in synchronization with the rotation of the gantry 6. 5 to irradiate the subject 7 with X-rays. Note that the X-ray source 5 emits X@ toward the subject 7 in a fan shape. Reference numeral 6 denotes a detector, which is mounted vertically opposite the X-ray source 5 and rotates together with the X-ray source 5, or is fixedly arranged in a concentric circle outside the circular locus in which the X-ray source 5 rotates. detects all transmitted X-rays that have passed through the subject 7 at each rotation angle of the X@ source 5,
It is configured to output projection data 8 to the calculation control section 1. 9 is an electrocardiogram respiratory monitor, which collects an electrocardiogram signal 11 and bioelectrical impedance 12 with a pair of electrodes 1o attached to the subject 7, and detects R waves from the electrocardiogram signal 11 as shown in FIG. By doing so, the R wave synchronization signal 11α is oscillated, and the bioelectrical impedance 12 T is Z as shown in diagram M3. (1
2b) and ΔZO(12(Z), Zo(12b
) oscillates a body movement detection signal 12d that detects a change in body position, Δ4 (12α) oscillates a deep breathing detection signal 12c that detects a deep breath, and then the body movement detection signal 12
d and the deep breathing detection signal 12c to create a body movement deep breathing detection signal 12g, and output the body movement deep breathing detection signal 12g to the arithmetic control cape section 1 together with the R wave synchronization signal 11α. Reference numeral 16 indicates a costume display, which is capable of displaying the X-ray CTH reconstructed by the arithmetic and control unit [&1] on, for example, a CRT monitor. Reference numeral 16 denotes an auxiliary storage device, which is a memory that temporarily stores the scan data obtained by temporally correlating the arithmetic and control unit [1].

Next, the operation of the heartbeat-linked X-ray CT device configured as described above will be described.

When an operator operates an operation console (not shown), a start control signal 2 is output from the arithmetic control section 1 to other sections of the apparatus. In response to the start control signal 2, the X-ray generation control device 14 generates a high voltage, and the gantry 6 rotates around the subject 7 by a constant rotation angle, for example, every 06 degrees. Then, in synchronization with the rotation of the pedestal 6, xH is irradiated to the subject 7 from the X-ray source 5 attached to the pedestal 6 at regular time intervals at every fixed rotation angle. The transmitted X-rays that have passed through the subject 7 are detected by the detector 6, and the detected data is output to the arithmetic and control device 1 as projection data.

In this way, when the X-ray source 5 emits X-rays once every 0.6 degrees of rotation angle and rotates around the subject 7 by 660 degrees, 600 degrees of radiation data are transmitted to the arithmetic and control unit. collected within. However, collection of projection data is achieved not only by one rotation of the X@ source 5, but also by rotating the X-ray source 5 around the subject 7 a predetermined number of times. Note that when the X-ray source 5 rotates once and returns to its original position, it takes a certain pause, and then projection data is collected again by rotating the X-ray source 5 around the subject 7.

On the other hand, the electrocardiogram/respiratory monitor 9 collects the electrograph signal 11 and bioimpedance 12 of the subject 6 through a pair of electrodes 10 attached to the subject 7 while the pedestal 6 is rotating. Rv synchronization signal 11 obtained by detecting the R drum from
While oscillating α, a body movement deep breathing detection signal 12g is created based on the bioelectrical impedance 12, and an electrocardiogram signal 11, an R wave shop j period signal 11α, and a body movement deep breathing detection signal 12g are output to the processing unit i[1. The arithmetic processing unit 1 temporally associates all the collected projection data 8 with the input electrocardiogram signal 11, R wave synchronization signal 11α, and body movement deep breathing detection signal 12-, and uses the associated data as scan data. Temporarily store it in the auxiliary storage @16. When the scan data of the predetermined number of scans is collected as photons in this way, the performance control unit 1 selects the photons shown in FIG. The heartbeat cycle is divided into equal parts, for example, 12, and projection data are extracted for each phase and rearranged as follows. That is, at a particular phase, for example, the second
For phase projection data, for example, as shown in FIG.
Of the single scan data during the period in which the state is in the state, projection data that temporally corresponds to the second phase 11b of the heartbeat cycle is extracted, and this is set as the first scan second phase data 14α. from the second
Scan second phase data 14b1 Extract the second phase data from all scan data such as the sixth scan second phase data 14C from the sixth scan data and convert it to X11j! Rearrange according to the rotation angle of the source. If the second phase data for a specific rotation angle cannot be obtained even through rearrangement, the heart Obtain all projection data 14 of the second phase for all rotation angles.

Phase data regarding other phases can also be obtained in the same manner as described above. By reconstructing the image for each phase data for all the rotation angles obtained, X@CTit for each phase of the heartbeat cycle is obtained, and this is displayed on the display device [16Q)C
Display on RT monitor.

The X-ray CTIH obtained as detailed above is reconstructed based on the projection data obtained by excluding the body movements of the subject 7 and the projection data during deep breathing. In the depths, there are no artifacts caused by him, and the spatial resolution is improved.

Although one embodiment of the present invention has been described above in detail, the present invention is not limited to the embodiment described above, and can be implemented with appropriate modifications within the scope of the gist of the invention.

1 [Effects of the Invention] According to this invention, even if the subject moves or takes a deep breath during radiation exposure and the heart position trembles by 1L, no gain can be obtained when the heart position changes. Since the image reconstruction is performed by excluding the projection data that has been
CT images with excellent spatial resolution and no artifacts can be obtained.

This makes it possible to provide a CT apparatus that can provide accurate medical diagnosis.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the positional relationship between an electrocardiogram signal and an R wave detection signal, and FIG. FIG. 4 is an explanatory diagram showing the positional relationship between body movement and deep breathing detection signals, FIG. 4 is an explanatory diagram showing equal division of the heartbeat cycle, and FIG. It is an explanatory diagram showing rearranging this.゛1・Calculation control! 41 capital, 2...start 1 cape signal, 6...mountain, 4...Xfi1 occurrence system cape mounting tribute,
5...X & 1 wife, 6...detector, 7.
...Subject, 8...Projection data,
9.--cardiac respiratory monitor, 10.--electrode, 11
... Electrocardiogram signal, 11α ... R wave synchronization signal, 11h
... Heartbeat cycle second phase, 12... Bioimpedance, 12-... Body movement deep breathing detection signal, 13...
Auxiliary storage device, 14... All projection data of a specific phase, 15... Interpolation data. Agent: Patent attorney Noriyuki Chika (and 1 other person) 1 (text 7″ /

Claims (1)

[Claims] By rotating around the subject and intermittently irradiating X-rays, it obtains projection data, simultaneously detects the subject's electrocardiogram signal, and reconstructs all projection data of a specific phase based on the detected electrocardiogram signal. In a heartbeat-linked X-ray CT device that displays CI images by
An electrocardiogram that detects the electrocardiogram signal and bioimpedance of the subject, detects R waves from the electrocardiogram signal, and generates an R wave synchronization signal that synchronizes with this and a body movement deep breathing detection signal that detects the displacement of the subject from the bioimpedance. respiratory monitor, the R-wave synchronization signal and the body j111] Deep is an auxiliary storage device that notates projection data in which the liquid detection signal and each projection data are temporally correlated, and a device that reads projection data from the auxiliary storage device. body! A heartbeat-linked X-ray CT characterized by comprising an arithmetic processing unit that selects projection data of a specific heartbeat phase from other projection data excluding projection data at a timing when a deep breathing signal is commonly used, and reconstructs an image. Device.