X-ray or gamma ray systems or devices – Specific application – Dental panoramic
Reexamination Certificate
1998-09-18
2001-01-09
Porta, David P. (Department: 2876)
X-ray or gamma ray systems or devices
Specific application
Dental panoramic
C378S098800
Reexamination Certificate
active
06173035
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a panoramic radiographic apparatus for entire jaw photographing and the like in dental examination and treatment for example, and to a digital sensor cassette used for the same apparatus.
2. Description of the Prior Art
A panoramic radiographic apparatus used in dental, otorhinolaryngologic and other clinics has a support for rotatably supporting a rotary arm provided with an X-ray generator at one end thereof and an X-ray detector at the other end thereof, and a film cassette loaded with an X-ray film is mounted in the X-ray detector and moved at a predetermined speed in accordance with the rotation of the rotary arm so as to carry out panoramic radiographing. In addition, it is also known that instead of the film cassette, a digital sensor cassette loaded with an electric X-ray image detector is mounted in the X-ray detector, and the electric X-ray image detector is driven under the control of control signals corresponding to the rotation of the rotary arm so as to obtain image signals required for generating a panoramic X-ray image (for example, in Japanese Laid-open Patent Application No. Hei 9-135829 and U.S. Pat. No. 5579361).
The apparatus disclosed in Japanese Laid-open Patent Application No. Hei 9-135829 is provided with both a film cassette and a digital sensor cassette so that either cassette can be selectively used depending on the object of operation, whereby the trouble of replacement is eliminated, and examination and treatment can be made speedily. However, the structure of the X-ray detector becomes complicated, an X-ray detector for generally-used film cassettes cannot be used, that is, a special X-ray detector is necessary. Furthermore, the digital sensor cassette is built in the apparatus and does not have a structure to be inserted into and withdrawn from a cassette holder. Moreover, the configuration of the digital sensor cassette as a single cassette has not been disclosed specifically.
In the apparatus disclosed in the USP, a digital sensor cassette is mounted in a cassette holder, and this cassette holder is moved. In addition, a structure for detecting the speed of the movement is necessary, making the structure of the X-ray detector complicated. Furthermore, there is no concrete disclosure indicating any structure for replacing the film cassette with the digital sensor cassette, whereby the replacement is made with difficulty.
Furthermore, a panoramic radiographic apparatus using a digital sensor is superior to a panoramic radiographic apparatus using a film in that because no development is necessary, a panoramic X-ray image can be obtained immediately and can be widely used for examination and treatment through the use of computers. However, almost all the panoramic radiographic apparatuses used in clinics are types used with film cassettes, and cannot be used with digital sensor cassettes. For these reasons, if the panoramic radiographic apparatuses used with film cassettes can be used with digital sensor cassettes by slight modifications, a great advantage can be expected.
SUMMARY OF THE INVENTION
In accordance with the above, an object of the present invention is to provide a panoramic radiographic apparatus wherein both a film cassette and a digital sensor cassette can easily be mounted in and removed from the X-ray detector of the apparatus, one at a time, without making the structure of the X-ray detector complicated. Another object of the present invention is to provide a digital sensor cassette compatible with the film cassette.
In order to attain the above-mentioned objects, the panoramic radiographic apparatus of the present invention is an apparatus having a support for rotatably supporting a rotary arm provided with an X-ray generator at one end thereof and an X-ray detector at the other end thereof, comprising a cassette holder capable of accommodating both a film cassette loaded with an X-ray film and a digital sensor cassette loaded with an electric X-ray image detector, one at a time, at the X-ray detector, and a control means for performing electric control so that when a film cassette is mounted in the cassette holder, the cassette holder accommodating the film cassette is mechanically moved in accordance with the rotation of the rotary arm at a predetermined speed in a direction nearly perpendicular to X-ray beams applied from the X-ray generator to the X-ray detector so as to carry out panoramic radiographing using a film, and so that when a digital sensor cassette is mounted in the cassette holder, with the cassette holder accommodating the digital sensor cassette being in a secured condition with respect to the X-ray detector, the electric X-ray image detector is driven by supplying control signals corresponding to the rotation of the rotary arm from the main body of the panoramic radiographic apparatus to the digital sensor cassette to obtain image signals required for generating a panoramic X-ray image.
The digital sensor cassette for the panoramic radiographic apparatus of the present invention comprises at least an electric X-ray image detector disposed in face-to-face relationship with the X-ray generator via an X-ray shield plate having a secondary slit and provided at the X-ray detector, driven by control signals supplied from the main body of the panoramic radiographic apparatus in correspondence with the rotation of the rotary arm, and used to convert X-rays to electric signals to deliver image signals required for generating a panoramic X-ray image; an A/D converter for converting analog signals delivered from the electric X-ray image detector into digital signals; an input/output portion for communicating with an external circuit; and a control portion for electrically controlling the operations of the above-mentioned various portions. The outer housing of the digital sensor cassette is nearly identical with a conventional film cassette loaded with an X-ray film in shape, and the digital sensor cassette can be mounted in the cassette holder for the film cassette, provided at the X-ray detector of the panoramic radiographic apparatus.
With these configurations, both the film cassette and the digital sensor cassette can easily be mounted in the cassette holder of the panoramic radiographic apparatus, one at a time, whereby required panoramic X-ray images can be obtained by fully using the features of each type of cassette.
The concrete configurations of the panoramic radiographic apparatus and the digital sensor cassette of the present invention will be clarified by the following descriptions regarding embodiments.
REFERENCES:
patent: 5018177 (1991-05-01), McDavid et al.
patent: 5784429 (1998-07-01), Arai
patent: 5844961 (1998-12-01), McEvoy et al.
patent: 5877501 (1999-03-01), Ivan et al.
patent: 5912942 (1999-06-01), Schick et al.
Furukawa Jun-ichi
Hayashi Takeshi
Ito Yutaka
Suzuki Masakazu
Tachibana Akifumi
Kabushiki Kaisha Morita Seisakusho
Koda & Androlia
Porta David P.
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