FI105448B - Method and apparatus for X-ray imaging of head and neck - Google Patents

Description

105448

Method and apparatus for X-ray imaging of head and neck

The present application relates to a method for X-raying the head and neck region, in particular to produce three-dimensional X-rays of an object to be imaged, using an X-ray imaging device and at least during exposure a digital imaging sensor positioned in the X-ray field of the X-ray source. The invention further relates to apparatus for X-ray imaging of the head and neck region, in particular for producing three-dimensional X-rays of an imaged subject, comprising an X-ray imaging device and a digital imaging sensor positioned at least during X-ray imaging of the target X-ray source.

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Three-dimensional imaging techniques, such as those disclosed in U.S. Patent Nos. 5,668,844 and 5,359,637, require multiple shots of a subject from different directions. Such multi-directional images can be taken automatically using, for example, the applicant's Fl application 980146, using a • t · 20 panoramic X-ray imaging device. Such a panoramic X-ray device does not · · ''; 'However, is not a viable solution when a 3D x-ray is desired

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take the patient without moving the dental chair. The panoramic X-ray device * also offers a limited range of motion for the x-ray source for optimal image quality. Thus, the invention of the invention.

One important object is to provide an improved method and apparatus for generating three-dimensional X-rays of any part of the head or neck, e.g., the tooth, which is further preferably automated.

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In order to achieve the objects of the invention, the method according to the invention is characterized in that the device emits an X-ray source at a desired distance from an irradiation plane located at an image sensor and an X-ray source M M f .......

'' is moved in said irradiation plane along a substantially circular path such that the central radius of the X-ray source points to the same point during motion; 2,104,448 that in the method the sensor is positioned at or near this point; and that, in order to photograph the subject from different directions, the X-ray source is optionally stopped at various points in the circular path during exposure in each desired imaging direction, or exposure is made while the X-ray source is in motion.

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Preferred embodiments of the method of the invention are described in dependent claims 2-7.

The apparatus according to the invention, in turn, is characterized in that the device 10 comprises means for positioning the X-ray source at a desired distance from the imaging sensor to a radiation level and means for moving the X-ray source at said radiation level along invested; and that the device includes means for optionally imaging the object in various directions to stop the circular path of the X-ray source during exposure in each desired imaging direction, or to perform exposure during X-ray motion.

Preferred embodiments of the apparatus according to the invention have been described.

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'' I in Independent Claims 10-12.

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The invention will now be described in more detail with reference to the accompanying drawings, in which:

Figures 1 and 2 schematically illustrate the flow of X-rays when applying the method of the invention, * · · *

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Figures 3-6 show the method used in the method of the invention

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30 exemplary embodiments of the apparatus, diagrammatically viewed from the side, from above, and from the front and in perspective, respectively, and 3 105448

Figures 7 and 8 show an detail of the apparatus of Figures 3-6 on an enlarged scale.

1 and 2, in the method of the invention, the X-ray source 5 is positioned to move in the irradiation plane along a circular path 20 such that central X-rays 21 of different locations 22 of the track 20 intersect at the same point 23, at which point sensor, for example, a radiation sensitive semiconductor sensor such as a CCD sensor or any other sensor system providing digital image information. The sensor is placed behind the subject, for example in the mouth or outside the mouth. The radiation receiving surface of this sensor is preferably located in a plane substantially parallel to the irradiation plane comprising the circular path 20. The angle 24 between the central beams 25 and 15 of the central axis of the circular path 20 is adjustable according to the desired image quality, i.e. layer thickness, and this angle also determines the distance of the irradiation plane from or to the image sensor 23. The determination of this angle is also influenced by whether the image sensor is inside or outside the mouth of the patient.

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When using the method, the X-ray motion can optionally be stopped during i · <• · «::: exposure in each desired direction of shot, at points 22 * · in a circular path 20. As the graph is pressed, the X-ray device illuminates the and automatically advance to the next scene. When • · · 25 digital image sensors have saved and transferred the image information to a further processing, eg on a computer, and the next image is ready • ♦ · ----------. ·: ·. for recording, the X - ray unit shoots the next image and continues until the circumference of the m - circle 20 is completely rotated. Shooting can also be performed with • «· the X-ray source moving at a sufficiently slow motion. Typically, pictures' r 30 are taken from 8 to 20, but there may be more or less.

The device used in the method according to the invention includes, in the case of the embodiment shown in Figures 3-8, a support structure e.g. a pillar-mounted connector 5 with a pivoting link 2 allowing movement in different directions. At the end of the articulated arm 2 is mounted a circular support arch 10 which is pivotable, for example, by means of a motor (not shown) arranged on the arm 2 about the first pivot axis A. Attached to the free outer end of the support arm 10 is a mounting fork 6 which is pivotable about the second pivot axis B, e.g. by means of a motor 13 covered by a protective housing 14. The supporting fork 6 is hinged by a pivot pin 7 having an X-ray source (not shown) the outgoing X-ray beam passes through the tubular portion 4 defining the beam field. The housing 3 is pivotable about the third pivot axis C, e.g. by means of a motor (not shown) located inside the housing. The first and second pivot axes A and B are preferably located substantially at an angle of 90 ° to each other, in the embodiment shown in Figs. 3-6, in a substantially horizontal plane, while the axis C is in a vertical plane. Such a three-axis rotary motion device 15 allows the X-ray source to be positioned in the desired direction of exposure with respect to the subject to be imaged and the X-ray source to travel along a circular path 20.

. . Further, the fork portion 6 is provided with an opening 9 with a measuring scale and a movable pointer 8 with which Ø · 20 can be easily set as desired.

The x-ray housing 3 is preferably balanced to avoid oscillation problems during rotation *. Alternatively or additionally, »» · 25 different pivot points of the pivot arm 2 may be lockable to eliminate vibration.

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When positioning an X-ray source at a desired irradiation level, its distance from the sensor can be measured and the alignment can be set, for example, mechanically, by a beam of light, or by ultrasound. For mechanical measurement, e.g.

* · 30 length-adjustable measuring rods, housed in a housing 3, which are placed • f * eg against an external mouthpiece connected to an image sensor. This distance determination can also be automated as needed.

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An intraoral X-ray device of the invention can be brought to the patient while sitting in a chair, thereby avoiding patient displacement. The device is especially designed for producing three-dimensional X-rays, but it can also be used for standard 5-D x-ray imaging if needed.

The invention is not limited to the above embodiments, but may be modified within the scope defined by the appended claims. For example, the means for positioning an X-ray source at a desired distance from the image sensor 10 to a radiation level may include an articulated arm 2 attached to a support structure, at its end provided with an articulated X-ray source housing 3 and X-ray source arranged to rotate within the rotation. This solution provides a slightly simpler mechanical solution which avoids, for example, the use of the support arch 10 and the attachment fork 6 shown in Fig. 8.

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Claims (12)

A method for X-raying the head and neck region, in particular to produce three-dimensional X-rays of an object being imaged, comprising using an X-ray imaging device (1) and at least during exposure a digital imaging sensor positioned from the X-ray field of the X-ray source characterized in that, in the method, the X-ray source of the device 10 (1) is positioned at a desired distance from the imaging sensor to an irradiation plane and the X-ray source is moved at said irradiation plane along a substantially circular path (20) such that the X-ray source that in the method the sensor is located at or near this point (23); and that, in order to photograph the subject from 15 different directions, the X-ray source is optionally stopped during exposure to the various points (22) of the circular path (20) in each desired imaging direction or when the X-ray source is in motion. •. A method according to claim 1, characterized in that • · · * 1 • · ·, ···. Moving 20 X-ray sources on a circular path (20), optional • · stopping the X-ray source at various points (22) on the track (20), and each exposure is performed • · * • · · · · ·. automatically. • · · · · · · · · · · · Method according to claim 1 or 2, characterized in that the transducer is placed in the mouth of the patient or outside the mouth of the patient at a point to be imaged. · ♦ · * · t • · ·: ·! ·. Method according to one of Claims 1 to 3, characterized in that: ···. when positioning the X-ray source at the desired irradiation level, measure the distance of the x-ray source · · Λ 30 from the sensor and mechanically apply the X-ray to the sensor. • · · • · 105448 7 Method according to one of Claims 1 to 3, characterized in that, when the X-ray source is placed at the desired irradiation level, the distance of the X-ray source from the sensor is measured and an X-ray is applied to the sensor by a light beam. Method according to one of Claims 1 to 3, characterized in that, when the X-ray source is placed at the desired irradiation level, the distance of the X-ray source from the sensor is measured and the X-ray is applied to the sensor by ultrasound. 6, 105448 Method according to one of the preceding claims, characterized in that the distance of the X-ray source from the sensor and the thickness of the imaging layer are adjusted by changing the angle (24) between the irradiation plane passing through the center beam (21) and the intersection point (23). . 8. Apparatus for X-raying the head and neck, in particular for producing three-dimensional X-rays of the subject, comprising an x-ray imaging device (1) and a digital imaging sensor positioned in the x-ray field of the imaging device (1) at least during exposure; Behind the 20 subjects to be photographed, characterized in that the device (1) comprises means • II; for positioning the x-ray source at a desired distance from the image sensor to a radiation plane and means for moving the x-ray source in said irradiation plane along a substantially circular path (20) such that the X-ray source: T: center beam (21) at or near the point (23) the sensor pn is located; and that the device includes means for optionally stopping the X-ray circular path (20) at desired locations (22) during exposure in each desired imaging direction, or to perform exposure to the object: • ·; · '··. during X-ray source motion .. 30 «·« f t I .1.1: Apparatus according to Claim 8, characterized in that the means for positioning the x-ray source at a desired distance from the image sensor to an irradiation plane include an articulated arm (2) attached to a support structure, to which end a support arm (10) pivotable about the first pivot axis ), in which a retaining fork (6) pivotable about the second pivot axis (B) is arranged in the support arch, and a housing (3) pivotable about the third pivot axis (C) is hinged and has an x-ray source on the inside. Apparatus according to claim 9, characterized in that said first and second pivot axes (A and B) are substantially at an angle of 90 ° to each other. 10 * Apparatus according to one of claims 8 to 10, characterized in that it further comprises means for measuring the distance between the x-ray source and the sensor and for applying the x-ray to the sensor. Apparatus according to Claim 8, characterized in that the means for positioning the X-ray source at a desired distance from the image sensor to the irradiation plane comprises a pivoting arm attached to a support structure, at its end being provided with an X-ray housing containing an articulated X-ray source. ·. ·. arranged to move in a rotational motion within the housing. »· · 20 • • • • • • • • • • • • • • • • • • • ••••••••••••••••••••••••••••••••••••••••••••••••••••••••• I · · · · · · · · · · · V • · r «« v · * · «mm * · · III * m · 9 105448