X-ray or gamma ray systems or devices – Electronic circuit – With display or signaling
Reexamination Certificate
2001-02-20
2003-06-24
Dunn, Drew A. (Department: 2882)
X-ray or gamma ray systems or devices
Electronic circuit
With display or signaling
C378S196000, C378S039000
Reexamination Certificate
active
06584171
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a medical X-ray imaging detector and a medical X-ray imaging apparatus so as to take out an image such as X-ray transmitted image of entire jaw in the field of dental surgery, oral surgery and otolaryngology.
2. Prior Art
An X-ray imaging detector using highly sensitive CCD (Charge Coupled Device) image sensor as imaging element comparing to a prior film type one recording X-ray transmitted image on an X-ray film has been used.
In a CCD image sensor, an electric charged image obtained by converting X-ray transmitted through an object into visible light by a scintillator is produced on a light receiver, the electric charged image is output in a form of voltage signal after time delay integrated, and finally A/D converted so as to be taken out as electronic image.
When panoramic X-ray imaging is executed for entire jaw, according to basic principle of imaging, transfer speed of electric charged image generated and accumulated on the CCD image sensor is required to be kept at a speed corresponding to rotational speed of a rotary arm in spite of relatively moving the object and the film at a prescribed speed. Such a principle is known as TDI (Time Delay Integration) imaging as shown in JP-A-61-22841, JP-A-2-84942, and JP-Y-4-48169.
In JP-A-11-104127 and JP-A-11-104218, an X-ray imaging detector which can directly take out an X-ray transmitted image as electronic image by incorporating an A/D converter in a CCD image sensor and an improved X-ray imaging apparatus in which such an X-ray imaging detector has compatibility with a conventional film detector so as to be detachable on a detector holder of an X-ray imaging apparatus have been proposed. Both of them have attempted to execute TDI imaging easily.
However, in the above-mentioned prior arts, an X-ray imaging apparatus is provided with a TDI clock generator and so on for executing TDI imaging and a TDI clock generator isn't provided for an X-ray imaging detector itself. Therefore, a TDI clock generator and so on should be provided for an X-ray imaging apparatus for TDI imaging so that it requires much cost for modifying a conventional film type X-ray imaging apparatus to an X-ray imaging apparatus using a CCD sensor. A technique for achieving TDI imaging at a low cost has been highly desired.
The prior arts have only taught an improved method wherein panoramic imaging producing X-ray transmitted image is produced on X-ray film has been substituted with electronic image, or an X-ray generator and an X-ray detector are moved interposing an object. Such prior art hasn't shown method wherein imaging time is speeded up and electronic image for adequate diagnosis is obtained.
The advantage of executing panoramic X-ray imaging at high speed is in that image out of focus caused by moving of an object is solved by shortening imaging time. Moreover, X-ray amount radiated on the object can be restrained and it is useful for reducing X-ray exposed dose amount.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problems. The first object of the invention is to provide an X-ray imaging detector wherein TDI (Time Delay Integration) imaging using an imaging element such as CCD can be executed even if an X-ray imaging apparatus isn't provided with a TDI clock generator.
The second object of the invention is to provide an X-ray imaging detector for executing high speed imaging, which is an ultimate object wherein suitable method hasn't been proposed in conventional TDI imaging using an imaging element such as CCD for obtaining X-ray image.
The third object of the invention is to provide an X-ray imaging detector which can generate electronic images with different resolutions by altering imaging mode according to diagnostic purposes.
Further object of the invention is to provide an X-ray imaging detector which is user-friendly improved from the view point of user in order to achieve the above-mentioned first to third objects.
Moreover, the other object of the invention is to provide a medical X-ray imaging apparatus which can achieve the above-mentioned objects by itself.
In order to solve the above-mentioned problems, the applicant of the present invention proposes an X-ray imaging detector, an X-ray imaging apparatus having an X-ray imaging detector, and an X-ray imaging apparatus having a function of an X-ray imaging detector by itself.
The present invention proposes an X-ray imaging detector for generating X-ray transmitted image in a form of electric signal for use in an X-ray imaging apparatus in which the X-ray imaging apparatus comprises an X-ray generator and a fixing means for fixedly positioning an object to be examined between the X-ray generator and the X-ray imaging detector mounted thereon, whereby X-ray imaging is performed by moving the X-ray generator and the X-ray imaging detector both interposing the object fixedly positioned by the fixing means while keeping facing each other. The X-ray imaging detector comprises an imaging element for generating electric charged image constituting X-ray transmitted image by detecting X-ray radiated from the X-ray generator and transmitted through the object, a TDI clock generator for generating TDI clock signal, and a TDI clock controller for controlling generating of TDI clock signal from the TDI clock generator based on TDI frequency control data for controlling the frequency of the TDI clock signal and for executing TDI control of the electric charged image generated by the imaging element corresponding to the TDI clock signal.
This X-ray imaging detector itself is provided with the TDI clock generator and the TDI clock controller and is a autonomic type detector of which imaging mode is such that the imaging element can be TDI controlled without receiving supply of TDI clock signal from the X-ray imaging apparatus. Therefore, if the TDI clock generator isn't provided for the X-ray imaging apparatus, TDI imaging can be achieved so that the above-mentioned first object can be accomplished.
A CCD imaging sensor is preferably used for an imaging element, however, any device can be used if it can execute TDI control.
According to the above-mentioned X-ray imaging detector of the present invention, the TDI clock controller may be provided with a clock control data memory storing the TDI frequency control data.
In such an X-ray imaging detector, the TDI clock controller has the clock control data memory. Therefore, it is convenient that the TDI frequency control data which has been stored by a manufacturer beforehand can be taken out from the memory and TDI imaging can be executed.
According to the above-mentioned X-ray imaging detector of the present invention, the clock control data memory may rewritablly store the TDI frequency control data.
In such an X-ray imaging detector, the clock control data memory is rewritable and the TDI frequency control data can be rewritten by a manufacturer at the time of shipment in order to meet the product specification of the X-ray imaging apparatus. Therefore, it is convenient that appropriate TDI imaging can be executed in compliance with the X-ray imaging apparatus when a manufacturer attaches the X-ray imaging detector on the X-ray imaging apparatus.
The control data memory is preferably constructed with a flash memory and EEPROM. However, any device can be used if stored data is rewritable and is kept even if an electric source is shut off.
According to the above-mentioned X-ray imaging detector of the present invention, the clock control data memory may store plural patterns of the TDI frequency control data.
In such an X-ray imaging detector, such control as enlarged imaging, maxillary antrum imaging, jaw joint imaging and selection of adult or child can be executed by storing plural patterns of TDI frequency control data in case of panoramic imaging using an X-ray imaging apparatus provided with an X-ray imaging detector. It is very convenient and can accomplish the above-mentioned third object.
According to t
Hayashi Takeshi
Ito Yutaka
Suzuki Masakazu
Tachibana Akifumi
Dunn Drew A.
J. Morita Manufacturing Corporation
Kao Chih-Cheng
Koda & Androlia
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