JPH0556959A - X-ray ct device - Google Patents

Abstract

PURPOSE:To surely eliminate the artifact occurring in the bodily movement by respiration in the auto voice scan of the X-ray CT device and to improve image quality. CONSTITUTION:A respiration sensor 7 which detects the respiration of a testee body 6 is provided and the scan is started when the stop of the respiration is detected (checked) by the respiration sensor 7 after the stop of the respiration is instructed by the auto voice scan. Namely, the scan is started not by the lapse of the time from the instruction for the respiration stop but by the actual respiration stop detected by the respiration sensor 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT apparatus having an automatic voice scanning function.

[0002]

2. Description of the Related Art In recent years, an X-ray CT apparatus having an automatic voice scan function has appeared. This is, for example, "hold your breath" or "make it easier"
For example, the scanning operation is performed while automatically uttering a predetermined instruction voice to the subject such as, for example, at a predetermined time point during a series of scanning operations, for the convenience of the operator.

By the way, in such an automatic voice scanning function, as described above, "hold your breath",
Alternatively, it is common to include a breath stop instruction such as “breath and stop,” and start scanning after the instruction (voice). For example, when performing a scan of a part of the subject's abdomen or chest that moves with breathing (particularly the abdomen) using the above function, first, utter a breath stop instruction to the subject, and then at a fixed time interval. The scan is automatically started. In this case, in general, the subject can stop breathing by the start of the scan, but in a weak subject, the response to the voice instruction is slow, and the scan may be started before the actual breathing is stopped. Not a few.

When the scan is started before the breathing is stopped in this way, an artifact is caused in the obtained CT image due to the body movement caused by breathing. Therefore, in the conventional device, the time interval between the voice instruction to stop breathing and the start of scanning can be arbitrarily adjusted, and the time interval is set long for a debilitated subject, and the scan is started when the subject stops breathing. Is adjusted.

[0005]

However, it is burdensome for the operator to adjust the scan start time interval depending on the subject. In any case, in the above conventional device, it is not to check whether or not the subject actually stopped breathing, and the scan may be started before the breathing is stopped. The problem of producing artifacts in CT images was unavoidable. An object of the present invention is to provide an X-ray CT apparatus capable of reliably removing an artifact caused by a body movement due to breathing without requiring any labor for an operator.

[0006]

The above object is to provide a respiratory sensor for directly or indirectly detecting respiration of the subject in an X-ray CT apparatus having an automatic voice scan function including a breath stop instruction to the subject. This is achieved by starting the scan by the auto voice scan function after the respiratory sensor detects the stop of breathing after the breath stop instruction.

[0007]

When the automatic voice scanning function is used, the breathing sensor directly or indirectly detects the breathing of the subject. Now, when the subject is instructed to stop breathing by the auto voice scan function, the output signal of the breathing sensor is X
It is monitored by the line CT device control processing unit (usually an image processing device) (may be monitored before the breath stop instruction). When the respiratory sensor detects that the subject has stopped breathing,
The device control processing unit starts scanning by the auto voice scanning function. According to this, since the scan is started at the actual stop of breathing detected by the respiration sensor instead of the passage of time from the instruction to stop breathing, the artifacts caused by the body movement due to breathing are reliably removed. At this time, the operator does not need any trouble.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an X-ray CT apparatus according to the present invention. In FIG. 1, reference numeral 1 is an X-ray tube, and 2 is an X-ray detector, which are arranged to face each other on a rotating plate (not shown) and form a main structure of a scanner.

Reference numeral 3 denotes a preamplifier that amplifies the output signal of the X-ray detector 2, and reference numeral 4 reconstructs an image based on the signal from the preamplifier 3 and controls each part of the X-ray CT apparatus main body such as the scanner. This is an image processing apparatus to which the auto voice scan function is added. Reference numeral 5 is a speaker for producing a predetermined instruction voice to the subject 6 by the auto voice scanning function. Here, the predetermined instruction voice includes a breath stop instruction (such as "hold your breath" or "breath and hold").

Reference numeral 7 is a respiration sensor that directly or indirectly detects respiration of the subject 6 and converts it into an electric signal. Here, a mask (not shown) is used as a respiratory sensor for direct detection.
There is a gas flow sensor attached to cover the mouth of the subject 6 and detects the call and the inhalation of the subject 6. Further, as a respiration sensor that indirectly detects, a belt (not shown) is attached to the abdomen of the subject 6 or in the vicinity thereof and the subject 6
There is a pressure sensor that detects the pressing force exerted by the abdomen. The figure shows the case where the former gas flow rate sensor is used.
Reference numeral 8 denotes an A / D converter which converts the signal (analog signal) of the breathing sensor 7 into a digital signal and gives it to the image processing device 4.

Next, the operation will be described. That is, X
The X-rays emitted from the radiation tube 1 are incident on the X-ray detector 2 via the subject 6, converted into an electric signal by the X-ray detector 2, and then amplified by the preamplifier 3. This operation is performed for the entire circumference of the subject 6, and all the signals obtained thereby are sent to the image processing device 4 to reconstruct the image.

At this time, the image processing device 4 outputs the scanner control signal S1 and the like to control each part of the X-ray CT apparatus main body such as the scanner, and at the same time, performs an automatic voice scanning operation (the above-mentioned instruction voice to the subject 6 is transmitted). At a predetermined time point during a series of scanning operations, the speaker 5 speaks and scans).

Such normal measurement operation and auto voice scan operation are not different from those of the conventional apparatus. In the present invention,
In the auto voice scan operation, after uttering a breath stop instruction such as "Hold your breath", check whether the subject 6 actually stopped breathing as follows, and start the scan. is there.

That is, during the automatic voice scanning, the instruction voice signal S2 is output from the image processing device 4 to the speaker 5 at a predetermined time point, and the speaker 5 gives the subject 6 an instruction to stop breathing. Here, the gas flow rate sensor (breathing sensor) 7 detects the call and the inhalation of the subject 6, and the output signal thereof is given to the image processing device 4 via the A / D converter 8. The image processing device 4 monitors the respiratory state of the subject 6 by the output signal of the gas flow sensor 7.

At the time of auto voice scan of the part which moves by breathing (especially the abdomen), the speaker 5 gives an instruction to stop the breathing to the subject 6, and when the subject 6 stops breathing accordingly, there is no call or inspiration. From that point, the output signal of the gas flow sensor 7 becomes zero. The image processing device 4 confirms that the subject 6 has stopped breathing when the output signal becomes 0, and starts scanning.

A predetermined waiting time may be set in the image processing apparatus 4 in advance, and after the output signal of the gas flow rate sensor 7 becomes 0, the scanning may be started after the waiting time. In this case, the waiting time functions as further confirmation of the respiratory arrest of the subject 6.

[0017]

As described above, according to the present invention, the scan is started not by the passage of time from the breath stop instruction but by the actual breath stop detected by the breath sensor, which is caused by the body movement due to breathing. Artifacts are surely removed, and at this time, there is an effect that the operator does not need any trouble.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a device of the present invention.

[Explanation of symbols]

 1 X-ray tube 2 X-ray detector 3 Preamplifier 4 Image processing device 5 Speaker 6 Subject 7 Gas flow sensor (respiratory sensor) 8 A / D converter S1 Scanner control signal S2 Instruction voice signal

Claims (1)

[Claims] 1. An X-ray CT apparatus having an automatic voice scan function including a breath stop instruction to a subject, comprising a respiratory sensor for directly or indirectly detecting the breath of the subject, and after the breath stop instruction, An X-ray CT apparatus, which starts scanning by the auto voice scanning function after the breathing sensor detects that breathing has stopped.