JPH01293845A - Panoramic x-ray imaging apparatus - Google Patents

Abstract

PURPOSE:To easily obtain the sharp tomographic image of the occipital region, by a method wherein a film moving direction is alternatively changed over in the same direction as the revolution of an arm and a film is moved at the variable speed corresponding to the predetermined tomographic orbit of the occipital region preliminarily stored in a memory means. CONSTITUTION:A flat plate-shaped cassette 13 is driven in the same direction as an arm revolving direction by a film driving control apparatus 15 and the moving speed of the cassette 13 is variably controlled so as to make it possible to take the tomographic image of the tomographic orbit of the occipital region preliminarily stored in the control apparatus, that is, that of the orbit of the peripheral region of a lower jaw head length axis, a cervical vectebra area and an internal/external ear hole. A microcomputer preliminarily storing a plurality of imaging programs of tooth/jaw region tomographic orbits is mounted and an operator alternatively selects the arbitrary track among them.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Purpose of the invention (a) Industrial application field The present invention relates to an improvement in a panoramic X-ray imaging device, and specifically relates to a panoramic X-ray imaging system of the entire jaw mainly focusing on the dentition area. This invention relates to a panoramic X-ray imaging apparatus that selectively performs panoramic imaging of the occipital region such as the long axis of the mandibular condyle, the vertebral position, or the area around the internal and external auricular foramen.

(b) Prior art and its problems Dental whole-mouth X-ray tomography equipment (hereinafter referred to as whole-town panoramic imaging equipment), which has become popular as an indispensable equipment for dental treatment in recent years, has an X-ray source and a film holder. In addition to one or several rotary drive motors that control the rotation of the horizontal arms that are disposed opposite to each other at both ends, there is also a cassette drive motor that controls the movement or rotation of the film (hereinafter referred to as cassette) in the film holding section. The number of so-called multi-motor type devices is increasing. This type of device rotates the arm and feeds the cassette.
Compared to a single-motor mechanical interlocking type, it is possible to detect the arm rotation phase and use this as a reference signal to freely control the cassette feed 41& using, for example, a microcomputer. It has its features. Taking advantage of this feature, you can increase or decrease the amount of X-rays in a specific range of dental electrolysis,
Alternatively, it is not possible to change the magnification ratio, and in particular, recently, multi-orbit tomography apparatuses that can arbitrarily select a plurality of tomographic trajectories in the dental and jaw region have been developed and commercially available. However, the tomographic trajectory of this type of device is usually a similar zonal fossa trajectory with different widths and depths, and there are rare cases that target the temporomandibular joint and can image the opening and closing positions of the temporomandibular joint. The section 1 trajectory is an extension of the above tooth curvature. In other words, in a plane viewed from above, the median sagittal plane direction is taken as the Y-axis, and the direction of the paper is taken as the X-axis.

Limited to fault trajectories within the first and second quadrant regions that include the face. This is because the rotation angle of the horizontal arm of the conventional device is generally limited to a range of 200 to 250 degrees due to restrictions of the rotation mechanism. Therefore, in other words, imaging a tomographic trajectory in the occipital region of the 3rd and 4th quadrants of the head plane requires not only the patient's position to be changed, which takes an hour, but also the selection of the imaging direction. It had the disadvantage of being difficult. However, in recent years, in order to obtain a true lateral image of the temporomandibular joint in xis diagnosis for temporomandibular joint disease.

It is said that it is suitable to set the plane perpendicular to the inferior long axis (the line connecting the outer pole and the inner pole) as the tomographic plane 2, and a number of images are taken to obtain the above-mentioned tomogram of the T1 long axis. Several methods have been tried, but all of them make it difficult to select the imaging direction and, in other words, position the patient.

Furthermore, it was easy to obtain sharp images with high diagnostic ability. Therefore, there is a growing demand in the dental medical field for a convenient device that can easily capture sharp tomographic images of the long axis of the mandibular condyle by simply switching the conventional full-mouth panoramic imaging device. The above-mentioned device is used not only in the dental field but also in the surgical field for diagnosing cervical vertebrae injuries caused by traffic accidents, tomographic imaging of the occipital region, including the area around the internal and external auditory canals in otolaryngology, and diagnosing the sphenoid sinus in the otolaryngology and ophthalmology fields. However, it is impossible to survive.

(C) Technical issues In addition to the conventional function of panoramic imaging of the dental and jaw region tomograms of a subject in a standing or sitting position, the present invention also has the ability to change the position of the subject (switchingly). This is to take a tomographic image of the occipital region, such as the long axis of the head.

C2+ Technical measures The technical measures taken to solve the above problems are as follows.

(a) Alternative switching of the direction of film movement of the film drive control device of the device for photographing a tomographic image of the dental and jaw region of a subject in a standing or sitting position to the same direction as the rotation of the arm.

(b) When rotating the arm, the film is moved at a variable speed corresponding to a predetermined tomographic trajectory of the occipital region stored in advance in the storage means.

That's true.

(3) Effect of technical means Although the device according to the present invention can be used as a single-motor mechanically interlocked full-jaw panoramic imaging device, it is possible to use a more effective multi-motor multi-orbital tomographic full-jaw panoramic imaging device. This is an improved device that can be easily switched in addition to the conventional function of arbitrarily selecting and photographing multiple trajectories of the teeth and jaw area. For example, the arm rotation device of this device was invented by the authors and filed in 1973.
As disclosed in the publication No. 9-M9g No. 28 "Arm rotation device of dental X-ray panoramic imaging device".

The horizontal arm is rotated by a planetary gear that engages with a fixed sun gear and revolves around it in a continuous uniaxial movement with no conversion point, and a cassette drive motor is provided separately from the rotation drive motor mentioned above to correspond to the arm rotation phase. This device controls the movement of the cassette at a variable speed. The feature of this arm rotation device is that it detects the arm rotation phase and speed continuously and with high precision, and uses this detection signal to derive arbitrary tomographic trajectory characteristics that are stored in advance in the memory of a digital circuit. This output signal is used to variably control the rotational speed of the cassette drive motor.

Furthermore, the structure and operation of an apparatus equipped with the above-mentioned arm rotating device and which uses a microcomputer to take a multi-orbital tomography of the dental and jaw region are described in Japanese Patent Application No. 179963-1988, which the author has already filed. Because it is published in the official bulletin of "Photography Equipment".

A detailed explanation will be omitted here. The device according to the present invention is an improvement of the devices shown in the above two publications, and the first improvement is that the direction of cassette movement can be freely switched between forward and reverse with respect to the direction of rotation of the arm. When photographing the occipital region, the direction should be changed to the forward direction, that is, the same direction as the arm rotation. The second improvement should be called an addition of functionality rather than an improvement, and is based on the mandibular condylar length and the tomographic trajectory characteristics that are stored in advance in the memory of the film drive control device that controls the moving speed of the cassette. The axial or cervical position, the area around the internal and external auditory foramina, or the sphenoid sinus may be added. For example, the orbital pattern of the long axis of the pediculid is discontinuous between only the left and right mandibular parts, and the orbital characteristics are either short straight lines or arcuate characteristics that are close to straight lines. By making the above two improvements, the rotation phase of the arm is, for example, 0.17, similar to the device disclosed in the publication.
The above-mentioned pre-stored trajectory pattern and trajectory characteristics are recalled through this detection signal, and the rotational speed of the cassette drive motor is controlled by the output signal, and the cassette moving speed is adjusted according to the tomographic trajectory. The effect of changing moment by moment in response to -0 is the same as the published device.
However, the distance between the focal point of the X-ray source and the film, which are installed opposite to each other at both ends of the arm, is the same as in the conventional device, but the tomographic trajectory in the occipital region is closer to the X41 source focal point than that in the jaw region, and is closer to the film than in the occipital region. Since the image is farther away, the magnification will be slightly larger. In addition, since the tomographic image is formed as a static image on the film every moment, so that the rotation of the X-ray beam and film appears to be stopped, the relative velocity of the film with respect to the rotational speed of the X-ray beam is is accelerated to the speed of the film holding section to a predetermined moving speed.

(4) Effects of the Invention Since the device according to the present invention is constructed as described above, it is possible to maintain the X
To orthogonally project the line beam and perform sharp tomographic corrections, the surgeon can perform simple and easy switching operations while the patient is positioned in a conventional full-jaw panoramic device, either standing or sitting on a chair. be. The improvements we made to the device for this purpose include a reversal function for the film movement direction of the film drive control device (the motor in conventional devices is originally a reversible motor, so it's just a matter of installing a reversing circuit), and the reversing function described above. For example, by simply adding a microcomputer memory that corresponds to the tomographic pattern and tomographic trajectory of the long axis of the mandibular condyle and outputs the speed signal momentarily in accordance with the rotation phase of the arm, No modification of the mechanical configuration of the conventional device is required. Therefore, the cost required for modification is low and it has the advantage of being easy to obtain. In addition, the operator's operations for tapping and shadowing are the same as those for positioning the affected area using conventional equipment, and when photographing the mandibles, the operator simply advances the center of the rotating device slightly relative to the positioned head. All the above-mentioned switching and photographing can be done by pressing buttons on the control panel, making it extremely simple. As mentioned above, the tomographic trajectories of the long axis of the mandibular condyle, the cervical vertebrae, and the sphenoid sinus are all local, so the X-ray beam irradiates only those local areas, and the trowel stops irradiating other areas. The radiation dose to patients can be extremely reduced. As mentioned above, the present invention enables the acquisition of sharp tomographic images of the occipital region, such as the long axis of the mandibular condyle, by a simple switching operation by inexpensively modifying the conventional full-mouth multi-orbital panoramic imaging device for dentistry. This provides a convenient device.

(5) Examples Specific examples of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing the imaging section of the panoramic X-ray imaging apparatus according to the present invention. The panoramic X-ray imaging device (1) includes an imaging stand (3) supported movably in the vertical direction by a main pillar (2) that is slid on a base (not shown).

An X-ray tube (9) is provided at one end of the arm (8), and its X-ray beam 001 passes through the subject's head 011 and passes through the horizontal arm (8).
For example, a flat cassette 03) containing an X-ray film that receives an image through a slit of a cassette holding part a21 suspended from the other end of the cassette holding part 021 is movable in a direction perpendicular to the X-ray beam 00). is supported by.

The item indicated by a dotted line inside the cassette holding part (12j) is a reversible motor for driving the cassette, such as a five-phase Varne motor, and (151 is the circuit part of the film drive control device that controls the drive of the motor 04). Examiner head 01
A pair of left and right ear rod support rods 061 for positioning
．． The positioning by the chin rest (171, U mark) and the light beam emitter (19, .) is the same as the full-jaw panoramic device.The above configuration is the same as the conventional full-jaw panoramic device. , which is the main part of this invention and is significantly different from the conventional device, is the film drive control device 05 described above.
) drives the flat cassette 03) in the same direction as the rotational direction of the arm, and the control device 05) is pre-stored to determine the tomographic trajectory of the occipital region, i.e., the long axis of the mandibular condyle and the cervical vertebrae position. .

The point is to variably control the moving speed of the cassette 031 so that a tomographic image of the trajectory around the internal and external auditory foramen can be taken. Figure 2 shows an example of the trajectory selection valve button section (■) installed on the operation panel of the X-ray control device (not shown) that sets the V voltage, tube current, etc. of the X-ray source of the imaging device (]). be. As shown in the above-mentioned Tokugansho publication, this device is equipped with a microcomputer pre-stored with imaging programs for multiple dental and jaw region tomographic trajectories, and the operator can select any trajectory from among them. Since I choose, I;,ru.

The push button (A) has two types of dentition) orbit (AIJ pediatric (A)
2) Summary button for adults, ■) is for the maxillary sinus orbit, (Ω is for 4-section imaging of the temporomandibular joint, but the explanation is omitted as it is detailed in the above publication.) and ( (G) is related to this invention, (D+ is for the inferior-head long axis trajectory, ■ is for the vertebral position trajectory. In the figure, an indicator light (2n) is placed above each push button to indicate the selected trajectory. The operator confirms this.No. 31 I performs tomography of the long axis trajectory (23R) (23R') of the left and right mandibular condylar flashes 1m11 by continuous movement of the arm using the arm rotation device shown in the above-mentioned Jitsugan Sho Publication. This is a diagram showing the situation.The above-mentioned (A1-(at the position of bowjonning of head 1 Qll when photographing the teeth and jaw area of O, the cause of the mandibular condyle)) exists at the position indicated by the dotted line, and its horizontal angle (α ) has a through position, flBl [71
(181Q9), move the center (5C) of the 11 rotation device along the median sagittal plane (support) of the head (
Move it in the direction a) and position it at (5d). This position correction operation is also performed in conventional devices and can be done extremely easily and quickly. The above center (5) is the circular arc group opposite to t) of the fixed sun gear, and the circular arc concentric with this is the planetary gear axis that is inscribed in the above sun gear and rotates and revolves, as shown in Figure 1. This is the locus of the arm rotation axis (7). The position of the rotation axis at the start of rotation is (7S), and the horizontal arm (8) fixed to this axis is located on the straight line connecting the center (Fi) of the rotation device and the above (7S), At the right end is the X-ray source (9
), and the cassette 031 of the cassette holding section 021 is placed opposite to the cassette 031 of the cassette holding section 021 at the left end at a predetermined distance. The caster is cassette 03)
After loading for this orbital shooting, press the ■ button above.

The rotation axis (7) revolves at a constant speed from (7S) to (7E) at the arrow mark (for example, approximately in the b1 direction) Q see as in the conventional device.The X-ray source (9) rotates clockwise (vl). X-ray focus (
9X) and film 03) relative distance (R+) (r
l) remains approximately constant. For example, the X-ray beam (1Xll) stops at the phase (R4) when it deviates from the orbit (Z3R). During this time, the cassette (131) is moved by the drive motor 041 of the cassette holding part O2 in the opposite direction T in the tooth and jaw area, that is, in the same direction as the movement of the holding part α21, and the X-ray beam α
Relative speed to 01! t (R2) is variably controlled. This (R2) is the phase of the film holding part, for example (F+
~F4), which is the cassette moving speed that changes slightly, and is calculated in advance using the theoretical formula shown in the above-mentioned patent application in order to form a sharp tomographic image of the above trajectory (23R) on the film. This is due to the trajectory characteristics of each fault stored in memory. When the arm rotation progresses further and the X-ray source (9) reaches the phase (R5), exposure starts again, and in the same manner as above (R8), the trajectory (23 m
) X-ray exposure stops when the imaging is completed. However, the arm (8) continues to rotate, and when the X-ray source reaches the position (9), the rotation stops and is divided into three parts. The means uses, for example, an encoder to detect the angle every 02 degrees and perform highly accurate film speed control corresponding to this detection.

(P1~P4) (P5~Ps) are the X-ray sources (
9) only the phase relationship is shown, and the relative position of the end relative to the size of the subject cannot be shown due to space limitations.

Next, cervical tomography will be explained with reference to FIG.

The cervical vertebrae position ■ is usually in the midsagittal plane c! 5), there is no need to shift the rotation device center (5C). After loading the cassette 031, the operator presses the button (C) in Figure 2, and the horizontal arm (8) starts to rotate clockwise, emitting the X-ray beam 00) in phase 1 (Pl). and the beam is at the right end (28
8), an arcuate trajectory (28R) close to the @ line is always projected squarely, while the relative distance between the trajectory, the X-ray focus, and the film (R2) (R2) is almost constant, and the left end (28R)
8E), the X-ray beam GO+ stops. During this time, the cassette (beam 131 (relative velocity W with respect to 101)
It is the same as above that (R3) is variably controlled. Fig. 5 is a plan view showing the area around the internal and external auditory foramina (29) (surrounding area including 2R+' +301 C31
11 is located close to the mandibular condylar area) and has the shape shown in Figure 1. Therefore, the mandibular circumference long axis trajectory (23R
) (23R') and a trajectory parallel to (30RX 30R')
can be taken in the same way as mandibular condylar long-axis imaging, so detailed explanation will be omitted. Furthermore, any trajectory that is not parallel can be photographed by slightly moving the position of the rotation device (5).

Next, although the sphenoid sinus exists between the analogous position and the anterior teeth, it is not shown because it can be photographed in almost the same manner as the cervical position.

The following is a specific example of the device according to the present invention.

It goes without saying that the present invention is not limited to what is illustrated or described. For example, the arm rotation device may not be of a uniaxial continuous movement type, but may be of a 3-axis conversion type, or may be of some other type. Further, the horizontal arm rotation phase detection method is not limited to the method using the encoder shown in the Utility Model Publication.

Furthermore, mechanical storage means using a tracing board or the like is also possible in the storage means of the film drive control device, including single motor mechanically interlocked devices. Further, the electrical storage circuit is not necessarily limited to a microcomputer memory, but may be a digital circuit or an analog circuit. The film in the film holding section does not need to be in a flat cassette, and a flexible cassette may be loaded onto the film drum. The arm rotation and film drive motors are also not limited to five-phase step motors. etc.

[Brief explanation of the drawing]

FIG. 1 is a side external view of the imaging section of the panoramic X-ray imaging device according to the present invention, FIG. 2 is a plan view of the trajectory selection push button section according to the present invention provided on the operation panel of the X-ray control device, and FIG.
The figure is an explanatory diagram of the tomography situation of the device, with the tomographic trajectory of the occipital region as the long axis of the mandibular condyle. FIG. 4 is an explanatory diagram of the tomography state of the apparatus in which the tomographic trajectory of the occipital region is set in the vertebral position, and FIG. 5 is a plan view showing the positional relationship of the area around the internal and external auditory foramen in the occipital region. (5)--Arm rotation device (5C)...Arm rotation device center (8)...Horizontal arm (9)--X-ray source (9X) '...X-ray focal point αO...・X-ray beam
Qli...Subject bright area (121...Film holder 03)...Flat cassette CLI...X-ray focus/distance between films (R+) (R2)...X-ray focus/subject Question circle M (r+) (r2)...Distance between subject and film M Q41...Film drive motor 05)...Film drive control liquid R■゛...Trajectory selection push button part of operation panel (A-AI -A2)... Long axis orbit button ■～... Occipital area vertebrae orbit Hotan (P
+~Pg)-...Horizontal arm rotation phase (Ku)--Left jaw (23R) (23R')...T vm Head long axis section N translation path Threshold (-Cervical position (281...)・Lateral tomographic trajectory (Vl)...Arm (X-ray source mI moving speed (constant speed) (V2) (V3)...Relative variable speed of the film to the X-ray beam @) Internal and external auditory foramen Surrounding area (3OR) (30R)...An example of the fault trajectory in the area around the internal and external auditory foramen

Claims (1)

[Claims] 1. An X-ray source and a film holder are disposed opposite each other at predetermined relative positions across the head of a subject in a standing or sitting position, and are horizontally rotatable. an arm, an arm rotation device that rotates the horizontal arm so that the X-ray beam is always squarely projected onto the teeth and jaw area while maintaining the predetermined relative position, and a rotation phase of the horizontal arm that is continuously detected. and a film drive control device for moving the film in the film holder in a direction opposite to the rotation of the arm at a variable speed corresponding to the tooth-and-jaw region tomographic trajectory prestored in the storage means based on the above-mentioned film drive control device. The film movement direction of the drive control device is selectively switched to the same direction as the arm rotation, and when the arm rotation is performed, the film is moved at a variable speed corresponding to a predetermined tomographic trajectory of the occipital region stored in advance in the storage means. A panoramic X-ray imaging device characterized in that it is configured to move. 2. The panoramic X-ray imaging apparatus according to claim 1, wherein the storage means of the film drive control device is an electrical storage circuit. 3. Whether the predetermined fault trajectory in the occipital region is the long axis of the mandibular condyle, the cervical vertebrae, the region around the internal and external auditory foramina, or the sphenoid sinus, or two of these. , or three, or all of the panoramic X-ray imaging apparatus according to claim 1 or 2.