JP3880118B2 - Dental panoramic tomography system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dental panoramic tomography apparatus.
[0002]
[Prior art]
In the conventional dental panoramic X-ray apparatus, the type using an X-ray film or the type using a CCD sensor, which is an electrical sensor, supports an X-ray film or a CCD sensor with an arm supporting an X-ray source. Are arranged on one plane parallel to the rotation axis. For this reason, a tomographic area is formed by translating the tomographic plane of the subject by the width of the X-ray film or the length of the CCD sensor with respect to the rotation axis.
[0003]
[Problems to be solved by the invention]
However, the actual tooth row is positioned inclined with respect to the rotation axis of the arm. That is, the front tooth portion of the actual tooth row has the crown portion inclined toward the X-ray film or CCD sensor side. Further, the tooth axis of the anterior tooth portion of the upper jaw of the patient and the tooth axis of the anterior tooth portion of the lower jaw are inclined so as to intersect with each other.
[0004]
Therefore, if the root part of the front tooth part is put in the tomographic area by the dental panoramic tomography apparatus, the crown part will deviate from the tomographic area. On the other hand, if an attempt is made to insert the crown portion of the front tooth portion into the tomographic region, the root portion will deviate from the tomographic region.
[0005]
The present invention has been made in view of the above circumstances, and changes the shape and position of a tomographic plane of a subject depending on the position of a tomographic information detection surface (irradiation field) in a tomographic information collecting means for forming a tomographic image. If, as a result, a tomographic area that approximates a complex-shaped tooth row can be obtained, it will be possible to obtain clearer tooth row information. It is an object of the present invention to provide a dental panoramic tomography apparatus that can set a tomographic region that approximates the entire tooth row that has been treated.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is an X-ray source that irradiates a tooth row that is a subject with X-rays, and a tomographic information collection unit that collects tomographic information of the tooth row included in transmitted X-rays transmitted through the tooth row. A dental panoramic tomography apparatus for obtaining a panoramic tomographic image of the tooth row, wherein the tomographic information collecting means comprises the X-ray source and a support that rotates while supporting the tomographic information collecting means. It has a plurality of tomographic information detection surfaces composed of scintillator layers having different distances from the rotation axis of the support.
[0007]
According to a second aspect of the present invention, in the dental panoramic tomography apparatus according to the first aspect, the tomographic information collecting means is provided with an optical fiber between a scintillator layer and a CCD sensor .
[0008]
According to a third aspect of the invention, the dental panoramic tomography apparatus according to claim 1, wherein the rotating part of the plurality of tomographic information detection surface made of a scintillator layer of the sectional Sojo paper collection means of the support It is characterized by being inclined with respect to the axis.
[0009]
According to a fourth aspect of the present invention, in the dental panoramic tomography apparatus according to the first aspect, a plurality of tomographic information detection surfaces composed of a scintillator layer of the tomographic information collecting means are at different distances with respect to the rotation axis of the support. It is characterized by being parallel arrangement of.
[0010]
According to a fifth aspect of the present invention, in the dental panoramic tomography apparatus according to the first aspect, the tomographic information collecting means includes a scintillator layer and a CCD sensor, and the inclination of the light receiving surface of a pixel group constituting the CCD sensor is determined. It is characterized by being adjustable.
[0011]
According to a sixth aspect of the present invention, in the dental panoramic tomography apparatus according to the third or fifth aspect, the tomographic information collecting means comprises a CCD sensor mounted on a flexible substrate and a scintillator layer. Is.
[0012]
Hereinafter, the operation of the present invention will be described in detail. According to the first aspect of the invention, since the tomographic information collection means for collecting tomographic information of a tooth row as an object has a plurality of tomographic information detection surface where the distance between the rotation axis is different of the support, the scintillator layer consisting of a plurality of tomographic data detection surface can collect tomographic information in accordance with the shape and position of the tomographic plane of an object can be constructed a clear tomographic image of the entire tooth row of complex shape.
[0013]
According to the invention of claim 2, since an optical fiber is provided between the X-ray detection means and the light receiving means, the degree of freedom of guiding the detection output of the X-ray detection means to the light receiving means is increased, and the teeth that are the subject Finer image formation of rows is possible.
[0014]
According to the third aspect of the present invention, a portion of the plurality of tomographic information detection surface made of a scintillator layer of the sectional Sojo paper collection means, since it is arranged obliquely with respect to the rotational axis of the support, It is possible to construct a clear tomographic image by collecting tomographic information of an inclined tooth row, which is an object, by a portion of the tomographic information detection surface in an inclined arrangement.
[0015]
According to the fourth aspect of the present invention, since the plurality of tomographic information detection surfaces made of the scintillator layer of the tomographic information collecting means are arranged in parallel at different distances with respect to the rotation axis of the support, According to the detection surface, it is possible to collect each tomographic information of each tooth constituting a tooth row having a different distance from the X-ray source and construct a clear tomographic image thereof.
[0016]
According to the fifth aspect of the present invention, the tomographic information collecting means is composed of a scintillator layer and a CCD sensor, and the inclination of the light receiving surface of the pixel group constituting the CCD sensor can be adjusted. The tomographic information according to the state can be collected and the clear tomographic image can be constructed.
[0017]
According to the invention described in claim 6, in the dental panoramic tomography apparatus according to claim 3 or 5, the tomographic information collecting means is constituted by a CCD sensor mounted on a flexible substrate and a scintillator layer. It is possible to flexibly set an inclination suitable for the tooth row for each patient.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0019]
1 and 2 illustrate an image construction method in the panoramic tomography apparatus according to the embodiment of the present invention. 1 and 2, an X-ray image of a point on S-A including the point O is formed at a point a. This is detected by X-ray film and recorded. At this time, the image formed at point a includes information on all points on the SA from the X-ray source to the X-ray film. S is the position of the X-ray source. In FIG. 1 and FIG. 2, another arbitrary point is M point, and the rotation center of the arm that supports the X-ray source and the X-ray film is R.
[0020]
Next, when the arm rotates and changes from position A to position B shown in FIG. 2, an X-ray image on S′-A ′ including another point O is generated at point a ′.
[0021]
At this time, if the image on the X-ray film that moves as the arm rotates moves from point a to point a ′, the X-ray image corresponding to point O is recorded at point a ′ on the X-ray film. . On the other hand, an X-ray image of a point on S′-B ′ including M point is generated at point b ′ at the position of the lower arm. Therefore, when the image on the X-ray film is moved from the point a to the point a ′, the X-ray image at the point M is recorded at the point b ′ when the position of the lower arm is reached.
[0022]
If the movement of the X-ray film is repeated while sequentially rotating the arm, the X-ray image at the point O is repeatedly recorded at an arbitrary point a on the X-ray film. On the other hand, the X-ray image of the M point is dispersed and recorded at each point on the X-ray film. For this reason, a sufficient degree of blackening cannot be obtained. In this way, only the X-ray image at the point O is emphasized, and a tomographic image at the point O is obtained.
[0023]
When a CCD sensor having a scintillator layer is used instead of the X-ray film, charges corresponding to the X-ray image are charged to the pixels at the point a. The CCD sensor sequentially transfers the charges charged in the cells constituting each pixel to the adjacent cells when information is called, and performs analog / digital conversion at the final end to output as a digital quantity.
[0024]
Here, X-rays are irradiated at the position of the arm shown in FIG. 2, and an X-ray image of the point on the SA is formed on the cell at the point a on the CCD sensor, and the charge corresponding to the intensity is charged. Is done. Assuming that the amount of charge is Q1, the amount of charge of Q1 is sequentially transferred to the adjacent cells. However, when the X-ray is irradiated again in the next cycle of the power supply frequency when the arm comes to the position of S, S ′ An X-ray image of the point on -A ′ is formed on the cell of point a ′.
[0025]
At this time, if the charge amount Q1 first stored at the arm position a has moved to the cell at the point a ', the charge of Q2 is charged in addition to the charge of Q1. Q2 is a charge amount corresponding to the transmitted X-ray dose at all points on S′-A ′. At this time, only the X-ray image at the point O is added twice.
[0026]
In this way, by appropriately controlling the charge transfer speed of the pixels of the CCD sensor, an X-ray image of a certain point is repeatedly formed on the X-ray film. Are repeatedly charged with the amount of charge corresponding to the X-ray image of the O point moving, thereby enhancing only the X-ray image of the O point and obtaining a tomographic image of the O point.
[0027]
Here, if the charge Q1 at the point a is moved to the point b ′ when the arm is at the position of the lower arm, the charge corresponding to the transmitted X-ray dose at the point on S′-B ′ including the point M is added to Q1. Adapted.
[0028]
As described above, the position of the obtained tomographic image can be changed by changing the speed at which the charged charges are transferred into the cells constituting the pixel.
[0029]
Here, consider a case where the CCD sensor is located farther from the X-ray source than the example shown in FIG. In FIG. 3, it is assumed that there are CCD sensors on the line segment FF ′ and the line segment ff ′. A transmission X-ray image of a point on SA including point O is imaged at point a on the CCD sensor on line segment FF ′, but c on the CCD sensor of line segment ff ′. It is imaged at a point.
[0030]
Next, when the arm rotates and the X-ray beam comes to the position shown in FIG. 3, the X-ray image of the point on S′-A ′ including the O point is the CCD sensor of the line segment FF ′. Above, the image is formed at the point a ′. At this time, in the CCD sensor on the line segment FF, if the charge moves from the point a to the point a ′, a tomographic image at the point O is obtained as in the case described above.
[0031]
Here, if a point where the charge has moved from the point c of the CCD sensor on the line segment ff ′ by the distance of the line segment aa ′ is c ′, the X-ray image formed at the point c ′ is The X-ray image of the O point is not included. That is, as the arm rotates, an X-ray image of a point included in S′-C ′ is formed at the point c ′.
[0032]
As apparent from FIG. 3, the X-ray image is formed only at the points c ′ and c ′ only at the point O ′ that is the intersection of SA and S′-C ′. Therefore, when there is a CCD sensor on the line segment ff ′, when the charge is moved by the same amount as in the case where the CCD sensor is on the line segment FF ′, the charge on the line segment FF ′. It can be understood that a tomographic image of the O ′ point closer to the X-ray source than the O point from which a tomographic image is obtained by the CCD sensor can be obtained.
[0033]
Next, FIG. 4 shows the overall configuration of the dental panoramic tomography apparatus of the present embodiment. The dental panoramic tomography apparatus shown in FIG. 4 includes X-rays formed by scintillator layers 29a to 29c and scintillator layers 29a to 29c that respectively form tomographic information detection surfaces for detecting X-rays transmitted through a tooth row from an X-ray source. Collecting tooth row tomographic information comprising optical fibers 30a to 30c for guiding light based on line detection and a CCD sensor 31 for receiving the light guided by the optical fibers 30a to 30c and converting it into electrical signals as tomographic information of the tooth row Fault information collecting means.
[0034]
Further, the dental panoramic tomography apparatus shown in FIG. 4 has a control circuit 21 for controlling the charge transfer rate of the pixel group of the CCD sensor 31, an image construction computer 22, an image monitor 24, and an X-ray (not shown). A control circuit 25 for the rotational speed of the arm holding the source, an X-ray head control circuit 26 (not shown), a CPU 27 including a memory, and an imaging start switch 28 are provided.
[0035]
As shown in FIG. 4, the scintillator layers 29a to 29c of the tomographic information collecting means are arranged such that the distance from the X-ray source, that is, the distance from the rotation axis of the arm holding the X-ray source is different. In this case, the scintillator layers 29a to 29c are arranged in a staggered manner so that the insensitive portion is not generated in the CCD sensor 31 and the dark portion is not generated in the image, thereby corresponding to the shape of the tooth row of the front tooth portion 4 as shown in FIG. The staggered fault areas 1 to 3 are obtained.
[0036]
Further, the tomographic information collecting means may be configured by a scintillator layer 29 provided with a convex portion 29x on a part of a flat portion 29y as shown in FIG. 6, an optical fiber 30, and a CCD sensor 31. .
[0037]
According to this tomographic information collecting means, it is possible to form a tomographic area corresponding to the protruding amount of the convex portion 29x. The dental panoramic X-ray imaging apparatus can obtain a sufficiently wide tomographic region when the distance between the rotation center of the arm and the subject is theoretically long, that is, in the case of the molar portion. Therefore, even if the tomographic area is changed by the convex portion 29x in this part, all the teeth enter the tomographic area.
[0038]
When the imaging part changes from the canine part to the front tooth part, the tomographic area becomes narrower. At this time, the tomographic region from the jaw portion to the root portion is formed by the flat portion 29y of the scintillator layer 29, and the tomographic region from the root portion to the crown portion is formed by the convex portion 29x of the scintillator layer 29.
[0039]
The tomographic region of the convex portion 29x corresponds to a more forward portion of the patient's face than the tomographic region of the flat portion 29y. Therefore, in the case of the conventional example, the tomographic area is thin and, for example, only the root part of the front tooth part enters the tomographic area, but the entire anterior tooth part including the crown part can be put in the tomographic area by this embodiment. It becomes.
[0040]
As the tomographic information collecting means, a scintillator layer 42 may be provided on a CCD sensor 41 formed on a flexible substrate 40 as shown in FIG. In this case, as shown in FIG. 8, when the scintillator layer 42 is formed for each pixel 41 a of the CCD sensor 41, crosstalk generated between adjacent pixels of the CCD sensor 41, that is, adjacent portions of the scintillator layer 42. Interference of light between each other can be prevented or reduced.
[0041]
In the dental panoramic tomography apparatus shown in FIG. 4, when the imaging start switch 28 is pressed, the CPU 27 that receives a signal from the imaging start switch 28 sends a power supply signal to the control circuit 26 of the X-ray head (not shown). The X-ray head is driven. Further, the CPU 27 sends a start signal to the arm rotation speed control circuit 25 and sends a transfer speed control signal to the pixel transfer speed control circuit 21 of the CCD sensor 31.
[0042]
The transfer control signal of the CCD sensor 31 is controlled in synchronism with the movement of the arm holding the X-ray source, but only the arm start position is detected by a limit switch or the like, and thereafter the current time of the arm is detected by the time counter. The position may be known, and the charge transfer rate of the pixel of the CCD sensor 31 may be controlled accordingly. Of course, the current position of the arm may be detected by a decoder, or the arm position may be detected by the number of pulses to the pulse motor for arm rotation.
[0043]
In this dental panoramic tomography apparatus, positioning of the front tooth portion, which is the subject of the patient, is performed by mechanically moving the height of the chin rest with a dial. At this time, a positioning gauge such as a laser pointer or a light beam can be used.
[0044]
Further, when photographing a subject, manual adjustment is performed so that the light beam follows the inclination of the tooth axis of the front tooth portion that is the subject, and information from a sensor provided in the adjustment mechanism is input and stored in the memory of the CPU 17. Alternatively, the image information of the anterior teeth by a TV camera provided separately is image-processed, and the position of the tooth root is estimated from the position of the crown of the anterior teeth and the inclination of the tooth axis, and the CPU 17 automatically Store in memory. By using such information for photographing the subject, an accurate tomographic image of the front tooth portion that is the subject can be obtained.
[0045]
By the operation of such dental panoramic tomography equipment, it is possible to collect tomographic information corresponding to tooth rows having complicated shapes and subtle differences in position, and tomographic images of tooth rows can be clearly constructed It becomes.
[0046]
【The invention's effect】
According to the first aspect of the present invention, tomographic information corresponding to the shape and position of the tomographic surface of the subject can be collected by a plurality of tomographic information detection surfaces made of a scintillator layer , and a clear tomographic image of the entire tooth row having a complicated shape is obtained. Can be provided.
[0047]
According to the invention of claim 2, since an optical fiber is provided between the X-ray detection means and the light receiving means, the degree of freedom of guiding the detection output of the X-ray detection means to the light receiving means is increased, and the teeth that are the subject It is possible to provide a dental panoramic tomography apparatus capable of forming a finer image in a row.
[0048]
According to the third aspect of the present invention, it is possible to provide a dental panoramic tomography apparatus capable of collecting tomographic information of inclined tooth rows and constructing a clear tomographic image thereof.
[0049]
According to invention of Claim 4, the dental panoramic tomography apparatus which can collect each tomographic information of each tooth which comprises the tooth row | line | column from which the distance from X-ray source differs, and can construct | assemble the clear tomographic image is provided. can do.
[0050]
According to the fifth aspect of the present invention, since the inclination of the pixel group constituting the CCD sensor can be adjusted, the tomographic information corresponding to the inclination state of the tooth row can be collected and the clear tomographic image can be constructed. A panoramic tomography apparatus can be provided.
[0051]
According to the sixth aspect of the present invention, there is provided a dental panoramic tomography apparatus capable of flexibly setting an inclination corresponding to a tooth and a tooth row for each patient and constructing a tomographic image with good image quality. Can do.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an image construction method in a dental panoramic tomography apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing an image construction method in the dental panoramic tomography apparatus of the present invention.
FIG. 3 is an explanatory diagram showing an image construction method in the dental panoramic tomography apparatus of the present invention.
FIG. 4 is a block diagram showing an embodiment of a dental panoramic tomography apparatus according to the present invention.
FIG. 5 is an explanatory diagram showing an example of a tomographic region in the dental panoramic tomography apparatus according to the present embodiment.
FIG. 6 is a diagram showing an example of tomographic information collection means in the dental panoramic tomography apparatus according to the present embodiment.
FIG. 7 is a diagram showing another example of tomographic information collection means in the dental panoramic tomography apparatus of the present embodiment.
FIG. 8 is a partially enlarged view of FIG. 7;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fault area 2 Fault area 3 Fault area 4 Tooth row 21 Control circuit 22 Image composition computer 24 Image monitor 25 Rotational speed control circuit 26 X-ray head control circuit 27 CPU
28 Shooting start switch 29a Scintillator layer 29b Scintillator layer 29c Scintillator layer 30a Optical fiber 30b Optical fiber 30c Optical fiber 31 CCD sensor

Claims (6)

An X-ray source that irradiates a tooth row that is a subject with X-rays, a tomographic information collection unit that collects tomographic information of the tooth row included in transmitted X-rays transmitted through the tooth row, the X-ray source, and tomographic information A dental panoramic tomography apparatus for obtaining a panoramic tomographic image of the tooth row, comprising a support that rotates while supporting a collecting means,
The dental tomographic imaging apparatus according to claim 1, wherein the tomographic information collecting means has a plurality of tomographic information detection surfaces composed of scintillator layers having different distances from the rotation axis of the support. 2. The dental panoramic tomography apparatus according to claim 1, wherein the tomographic information collecting means includes an optical fiber between the scintillator layer and the CCD sensor. Dental panoramic claim 1, wherein the portion of the plurality of tomographic information detection surface made of a scintillator layer of the sectional Sojo paper collection means is arranged obliquely to the axis of rotation of the support Tomography equipment. The dental panoramic tomography apparatus according to claim 1, wherein the plurality of tomographic information detection surfaces including the scintillator layer of the tomographic information collecting unit are arranged in parallel at different distances with respect to the rotation axis of the support. . 2. The dental panoramic tomography apparatus according to claim 1, wherein the tomographic information collecting means comprises a scintillator layer and a CCD sensor, and the inclination of the light receiving surface of the pixel group constituting the CCD sensor can be adjusted. 6. The dental panoramic tomography apparatus according to claim 3, wherein the tomographic information collecting means comprises a CCD sensor mounted on a flexible substrate and a scintillator layer.

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