JP3181162B2 - Dental X-ray imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an X-ray image relating to a diagnostic site or a therapeutic site in the oral cavity as an electric signal, and performing a CR-detection.
The present invention relates to a dental X-ray imaging apparatus for displaying an image on a T (cathode ray tube) or the like.

[0002]

2. Description of the Related Art Conventionally, in order to obtain an X-ray image of an intraoral site, a film system in which an X-ray is taken using a photosensitive recording material such as a silver halide film and then developed and fixed is widely used. Have been.

However, this film method requires 1) a time of about 2 minutes or more from X-ray imaging to observation.
2) A developing device and a processing solution for performing the developing and fixing processes are indispensable. 3) The X-ray sensitivity of silver salts is limited, and a certain amount of X-ray is required to obtain a desired image density.
4) The image once fixed cannot be corrected. There is such a problem.

In order to solve such a problem, CCDs
2. Description of the Related Art An X-ray image capturing apparatus that converts an X-ray image into an electric signal using an image pickup device such as a (charge-coupled device) and displays the image on a CRT (cathode ray tube) or the like has been proposed. This X-ray image photographing apparatus does not use a photosensitive recording material such as a silver halide film, and is a so-called filmless system. 1) Observation can be performed in real time from the time of X-ray photographing. 2) No developing device or processing solution is required. 3) Since the image sensor has high sensitivity, X
The radiation dose can be reduced. 4) The detected X-ray image can be easily subjected to various image processing, and can be easily copied and stored. It has features such as.

[0005]

In the conventional film system, preparation for X-ray irradiation is completed when the X-ray film is positioned in the oral cavity of the patient, and X-ray irradiation can be performed at any time from that point. become.

On the other hand, in the latter X-ray imaging apparatus, in order to reduce the dark current of the image sensor, charges (such as charges caused by X-ray photons incident and charges caused by thermal excitation) accumulated in a light receiving portion of the image sensor are periodically reduced. A so-called blank read operation of reading out data in a readable manner is performed. Therefore, if X-ray imaging is performed during the period in which this operation is being performed, there is a problem that a complete X-ray image cannot be obtained. In addition, during a period in which the image processing means is performing predetermined image processing on the X-ray image of the previous imaging or a period in which other processing is being performed, a new X-ray image is generated for the image sensor.
Even if the line irradiation is performed, the signal from the image pickup device cannot be captured by the image processing means, resulting in a failure in X-ray imaging.

An object of the present invention is to solve the above-mentioned problem by realizing a cooperative operation between the X-ray irradiating means and the image processing means, so that the image processing means is performing some processing so that the X-rays can be transmitted from the image sensor. An object of the present invention is to provide a dental X-ray imaging apparatus capable of preventing erroneous irradiation of X-rays when an image cannot be captured.

[0008]

According to the present invention, there is provided an X-ray generating means for irradiating an X-ray toward an intraoral part of a subject;
An image pickup device for detecting an X-ray image of an intraoral region, an image processing unit for reading an X-ray image detected by the image pickup device, and performing predetermined image processing; A busy signal sending means for sending a busy signal indicating that the image processing means is processing, and when not receiving the busy signal, generating a start signal for starting the X-ray generating means, An X-ray control unit which does not generate the activation signal when received.

Further, the present invention provides an X-ray tube for irradiating an X-ray toward an intraoral part of a subject, an image pickup device for detecting an X-ray image of the intraoral part, and an image pickup element. X
Image processing means for reading a line image and performing predetermined image processing; busy signal sending means for sending a busy signal indicating that the image processing means is processing during a processing period of the image processing means; A high-voltage circuit that supplies a high voltage to the X-ray tube when the busy signal is not received and a high-voltage circuit that does not supply the high voltage to the X-ray tube when the busy signal is received. An image capturing device.

[0010]

[0011]

According to the present invention, during the processing period of the image processing means, a busy signal indicating that the image processing means is processing is transmitted to the X-ray control means, so that the X-ray control means can perform image processing. It becomes possible to recognize the processing state of the means. The X-ray control means does not generate an X-ray generation start signal when receiving the busy signal. As a result, even if the operator attempts to generate X-rays by mistake, the subject is not irradiated with X-rays, and erroneous X-ray irradiation can be prevented.

According to the invention, during the processing period of the image processing means, the high voltage circuit sends a busy signal to the high voltage circuit to the effect that the image processing means is processing. Can be recognized. When the high voltage circuit receives a busy signal, X
Do not supply high voltage to the tube. As a result, even if the operator attempts to generate X-rays by mistake, the subject is not irradiated with X-rays, and erroneous X-ray irradiation can be prevented.

[0013]

[0014]

FIG. 1 is a diagram showing a use state of a dental X-ray imaging apparatus according to the present invention. The X-ray generator 10 is attached to the free arm 12 so as to be vertically swingable and horizontally rotatable, and the direction of the X-ray irradiation tube 11 is set so that the X-ray is irradiated toward the intraoral part of the subject 1. Is adjusted.

On the other hand, the X-ray irradiation tube 11
The imaging device 2 for detecting the X-ray intensity distribution that has passed through the intraoral region, that is, the X-ray image, is positioned at a position opposite to. In FIG. 1, the subject 1 itself holds a positioning member 2 a fixed to the imaging element 2 with a finger such that the imaging surface of the imaging element 2 faces the X-ray irradiation direction.

The imaging device 2 includes a scintillator plate made of a rare earth element compound for converting X-ray photons into visible light, for example, and a visible light radiated from the scintillator plate.
An optical fiber array that transmits the dimensional distribution as it is, a CCD array sensor that receives the visible light distribution transmitted by the optical fiber array, accumulates the generated charges, sequentially reads out the accumulated charges for a predetermined time, and converts them into electric signals A lead plate for preventing the incidence of scattered X-rays is provided on the back of the CCD array sensor, and these are housed in a housing made of synthetic resin or the like. The X-ray image detected by the image sensor 2 is converted into an electric signal by a CCD array sensor, and is passed through a signal cable 3 to an image processing device 4.
Is input to

The image processing device 4 digitizes a signal from the image pickup device 2 and stores it in a memory, and then performs predetermined image processing to display the signal on a monitor device 5 such as a CRT (cathode ray tube) or a recording paper. Print on to get a hard copy.

FIG. 2 is a block diagram showing an electrical configuration of one embodiment of the present invention. The image processing device 4 includes a CPU (central processing unit) 31 for controlling the entire operation,
A ROM (random access memory) 32 for storing programs and data necessary for the operation of the
A main memory 33 for storing image data and parameters necessary for arithmetic processing such as image processing, and an image memory 3 for storing image data to be displayed on the monitor device 5
And a DA conversion circuit 35 for converting the image data stored in the image memory 34 into an analog video signal VD and outputting the analog video signal VD to an external monitor device 5 or video printer 6.
A direct memory access (DMA) controller 36 for controlling data transfer between circuits without the involvement of the CPU 31; and a clock signal CK necessary for operating the image sensor 2 such as a CCD sensor. A clock signal generating circuit 38 and a preamplifier 39 for capturing and amplifying the image signal SG output from the image sensor 2
An AD conversion circuit 40 for converting an output from the preamplifier 39 from an analog signal to a digital signal; and an input / output circuit 41 for supplying data to an external printer 42
An input / output circuit 43 for taking in data from a keyboard 44 for inputting data, and an external X-ray controller 2
0, an input / output circuit 45 for issuing a busy signal BUSY, receiving an exposure signal EXP from the X-ray controller 20, and a bus 37 for interconnecting these circuits.
Etc.

In the image pickup device 2, charges accumulated for a certain period of time are periodically read out as dark currents based on a clock signal CK from a clock generation circuit 38, and thermal excitation and scattering X
It is kept so that no extra charge due to lines or the like remains.

The X-ray controller 20 outputs a start signal TG to the X-ray generator 10 in accordance with an instruction from the exposure switch 21, and the X-ray generator 10 outputs a tube voltage, a tube current, and a tube current based on the start signal TG. By applying a high voltage to the X-ray tube 13 under predetermined X-ray irradiation conditions such as an irradiation time,
Generates X-rays.

Next, the overall operation of the image processing apparatus 4 will be described. When the exposure switch 21 of the X-ray controller 20 is pressed, the X-ray generator 10 emits X-rays for a predetermined time. When the X-rays reach the imaging device 2 through the subject 1a, charges corresponding to the X-ray image applied to the imaging device 2 are accumulated, and are output in a time series as an image signal SG after the end of the X-ray exposure. You. The image signal SG from the image sensor 2 is input to the preamplifier 39 and amplified to a predetermined level.
The data is input to the D conversion circuit 40 and is converted into a digital value.
At this time, the DMA controller 37 occupies the bus 37 and the image data output from the AD conversion circuit 40
7 are sequentially stored in a part of the main memory 33.

On the other hand, even when there is no X-ray exposure,
Is periodically read out, and the AD conversion circuit 40
Is converted into a digital value, and stored in a part of the main memory 33 as dark current data.

The image data and the dark current data stored in the main storage memory 33 are subjected to arithmetic processing by the CPU 31, and for example, the dark current data is subtracted from the image data and stored in a part of the main storage memory 33 again. By
Background noise can be eliminated from image data, and high-quality image data can be obtained. In addition,
If the dark current noise can be ignored, the subtraction processing may be omitted to shorten the entire processing time.

The image data stored in the main memory 33 is transferred to the image memory 34 by the DMA controller 37. The content stored in the image memory 34 is DA
The data is read out to the conversion circuit 35 in time series, and the DA conversion circuit 35 converts the digital image data into an analog video signal VD and outputs the analog video signal VD to the monitor device 5 and the video printer 6. The X-ray image detected by the image sensor 2 in this manner is
A hard copy is displayed on the screen of the monitor device 5 or obtained by the video printer 6. If necessary, the video signal VD can be recorded by a recording device such as a video tape recorder.

FIG. 3 is a flowchart showing the operation of one embodiment of the present invention. First, starting from step a1, in step a2, the CPU 31 determines whether or not the keyboard 44 has been operated to input a command for instructing a specific process. If there is no keyboard operation, the process proceeds to step a6. If there is a keyboard operation, the flow shifts to step a3, where the CPU 31 sets a busy signal BUSY and sets it to a high level. The busy signal BUSY is input to the X-ray control device 20. If the busy signal BUSY is at a high level, the X-ray control device 20 determines that the image processing device 4 is not ready, and 1
It operates so as not to generate the activation signal TG for 0.
Even if the exposure switch 21 is pressed in this state, the activation signal TG
, The X-ray generator 10 does not operate. Therefore, erroneous X-ray exposure can be reliably prevented during the processing of the image processing device 4.

Next, in step a4, the CPU 31 or the DMA controller 36 executes a process corresponding to the command input by the keyboard operation. When this processing is completed, next, in step a5, the CPU 3
1 lowers the busy signal BUSY and sets it to the low level, and then proceeds to step a6. When the busy signal BUSY is at the low level, the X-ray controller 20 determines that the image processing device 4 is ready and allows the generation of the start signal TG, and in this state, the exposure switch 21 is pressed. Then, a start signal TG is issued, and X-rays are generated from the X-ray tube 13 of the X-ray generator 10 under predetermined X-ray irradiation conditions.

In step a6, the CPU 31 determines whether or not the exposure signal EXP has been input from the X-ray control device 20 to the image processing device 4. The exposure signal EXP informs the image processing device 4 when the X-ray irradiation has started and when the X-ray irradiation has ended. For example, the exposure signal EXP keeps a high level from the start of the exposure to the end of the irradiation. Keep low level for the rest of the period. In this step a6, the exposure signal E
If there is no input of XP, the process returns to step a2 again. On the other hand, if the exposure signal EXP is input and, for example, is at a high level, it means that the X-ray generator 10 is performing the X-ray emission operation, and the process proceeds to the next step a7, where the X-ray emission is performed. Is completed and the exposure signal EXP is inverted to a low level, for example.

When the X-ray irradiation is completed, the next step a8
Then, as in the step a3, the CPU 31
Raises the busy signal BUSY and sets it to a high level, the X-ray controller 20 operates so as not to generate the activation signal TG, and prohibits X-ray exposure.

In the next step a9, the image signal SG of the subject 1a output from the
9. After being taken into the main storage memory 33 via the AD conversion circuit 40 and the bus 37, the image is subjected to dark current data subtraction processing, negative / positive inversion, enlargement, up / down conversion, density conversion, coloring display, etc. as necessary. The processing is executed by the CPU 31,
Image data for display is created. Next step a10
In, the image data created in the main storage memory 33 is transferred to the image memory by the DMA controller, converted into the video signal VD via the DA conversion circuit, and displayed on the monitor device 5 or the like.

When the processing of the image processing apparatus 4 is completed, in the next step all, the CPU 31 sends the busy signal BU
After lowering SY and setting to low level, step a2
Then, it is determined whether the keyboard operation or the exposure signal EXP has been input.

As described above, when the image processing apparatus 4 is executing any processing, the X-ray control apparatus 2 indicates that the processing is being performed.
By notifying to 0, the X-ray control device 20 can determine whether or not X-ray exposure is possible, so that it is possible to prevent X-ray imaging from being performed before the image processing device 4 is ready.

FIG. 4 is a block diagram showing an electrical configuration of another embodiment of the present invention. This embodiment is the same as that of FIG. 2 except that the busy signal B
The difference is that USY is input to the X-ray generation permission device 50, and the X-ray generation permission device 50 directly opens and closes the high voltage circuit of the X-ray generation device 10 according to the level of the busy signal BUSY.

The X-ray generation permission device 50 outputs a busy signal BU
It includes a photocoupler 51 to which a current loop 46 for transmitting SY is connected, and a relay 52 for opening and closing a high voltage circuit of the X-ray generator 10.

[0034] The X-ray generator 10 includes the filament wire 1
4, the power is supplied through the common line 15 and the high voltage line 16, and the primary side of the filament transformer FT is connected between the filament line 14 and the common line 15; The primary side of the high voltage transformer HT is connected between the high voltage line HT and the switch 52b of the relay 52 in the middle of the high voltage line 16.
Intervenes. The secondary side of the filament transformer FT is connected to the filament 13b of the X-ray tube 13, while the secondary side of the high voltage transformer HT is connected between the anode target 13b of the X-ray tube 13 and the filament 13b. The high voltage circuit shown in FIG. 4 includes a high voltage transformer HT and a filament transformer F.
Although an example of a pre-ignition system having two transformers of T is shown, the present invention is also applicable to a simultaneous ignition system having both functions with one transformer.

Next, the overall operation will be described. When the image processing apparatus 4 is executing some processing, that is, in a so-called busy state, almost no current flows in the current loop 46, and The light emitting diode 51a is turned off, and the phototransistor 51b is turned off. The phototransistor 51b is a relay 52
If the phototransistor 51b is in a cut-off state, the relay 52
Does not operate, the switch 52b is cut off, and the high-voltage line 16 of the X-ray generator 10 is cut off. Even if the exposure switch 21 is pressed in this state, the X-ray controller 20 outputs the activation signal TG, and the operation of the X-ray generator 10 starts, the high-voltage line 16 is cut off. No voltage is applied to the tube 13 and no X-rays are generated.

On the other hand, when the image processing apparatus 4 is not operating at all, that is, in a so-called knot busy state, a predetermined current flows through the current loop 46, and the light emitting diode 51a
Emits light, and the phototransistor 51b is turned on. When the phototransistor 51b becomes conductive, the relay 5
2 operates, the switch 52b conducts, and the X-ray generator 10
Of the high voltage line 16 is conducted. In this state, when the exposure switch 21 is pressed, the X-ray control device 20 outputs a start signal TG, and the operation of the X-ray generation device 10 starts.

In the following, the preignition method will be described as an example.
First, a predetermined filament current flows through the filament wire 14, and the filament 13a of the X-ray tube 13 is heated. Then, a predetermined voltage is applied to the high-voltage line 16, and a predetermined voltage is applied to the anode target 13b of the X-ray tube 13. Is applied, a predetermined tube current flows for a predetermined irradiation time, and X-rays are generated from the anode target 13b.

As described above, when the image processing apparatus 4 is executing some processing, the supply of the high voltage to the X-ray tube 13 is forcibly stopped based on the busy signal BUSY indicating that the processing is being performed. Thereby, it is possible to prevent the X-ray imaging from being performed before the image processing apparatus 4 is ready.
The present embodiment has an advantage that it can be realized by slightly changing the connection of the high-voltage circuit to the existing X-ray apparatus, and therefore, it is easy to cooperate with an X-ray imaging apparatus using a CCD sensor. Is achieved.

[0039]

As described above in detail, according to the present invention, even if a worker erroneously generates X-rays during the processing period of the image processing means, the subject is not irradiated with X-rays.
Erroneous irradiation of X-rays can be prevented beforehand. Therefore, unnecessary X-ray exposure to the subject can be suppressed, and X-ray imaging can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a use state of a dental X-ray imaging apparatus according to the present invention.

FIG. 2 is a block diagram showing an electrical configuration of one embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of one embodiment of the present invention.

FIG. 4 is a block diagram showing an electrical configuration of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Subject 2 Image sensor 2a Positioning member 4 Image processing device 5 Monitor device 6 Video printer 10 X-ray generator 11 X-ray irradiation tube 12 Flexible arm 13 X-ray tube 20 X-ray controller 21 Exposure switch 31 CPU 33 Main memory memory 34 Image memory 35 DA conversion circuit 36 DMA controller 37 Bus 38 Clock signal generation circuit 39 Preamplifier 40 AD conversion circuit 50 X-ray generation permission circuit 51 Photocoupler 52 Relay

──────────────────────────────────────────────────続 き Continuation of the front page (72) Takao Makino, Inventor Morita Manufacturing Co., Ltd. 680, Higashihama-minami-cho, Fushimi-ku, Kyoto-shi, Kyoto (56) References 173538 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 6/00-6/14

Claims (2)

(57) [Claims] 1. An X-ray generating means for irradiating an X-ray toward an intraoral part of a subject, an image sensor for detecting an X-ray image of the intraoral part, and an X-ray detected by the image sensor. Image processing means for reading a line image and performing predetermined image processing; busy signal transmitting means for transmitting a busy signal indicating that the image processing means is processing during a processing period of the image processing means; A dental signal generator for generating an activation signal for activating the X-ray generating means when the busy signal is not received, and an X-ray control means for not generating the activation signal when the busy signal is received. X-ray imaging apparatus for use. 2. An X-ray tube for irradiating an X-ray toward an intraoral site of a subject, an imaging device for detecting an X-ray image of the intraoral site, and an X-ray detected by the imaging device Image processing means for reading an image and performing predetermined image processing; busy signal sending means for sending a busy signal indicating that the image processing means is processing during processing of the image processing means; A high-voltage circuit that supplies a high voltage to the X-ray tube when no signal is received, and that does not supply a high voltage to the X-ray tube when the busy signal is received. Shooting equipment.