FR2596603A1 - Radiographic digitising device usable in particular in dental technology, with a view to delivering a negative in real time - Google Patents

Abstract

Radiographic digitising device usable in particular in dental technology to enable a negative to be obtained in real time. This device consists of an imaging system 13 having, on the one hand, a cathode tube 11 restoring the radiographic image, and on the other hand an assembly of electronic boards 10 and an alphanumeric keyboard 12. An interface 16 is linked to the sensor 12 via a flexible connecting system 4. The device is worked through a trigger 14, the emitter 1 sensitises the sensor 2 whose signals are processed by the digital package 13 which displays the negative on the cathode screen 11 instantaneously. The device according to the invention is particularly intended for dental diagnosis and treatment.

Description

1 - Description
The present invention relates to a radiographic digitalization device, usable in particular in dental technique, to allow obtaining a photograph in real time.

The taking of dental pictures is traditionally carried out using silver film, which requires the use of a large dose of ionizing radiation on the one hand, on the other hand, it requires long and expensive manipulations of the treatment of movie
Some silver films have improvements in their sensitivity, but despite a lower dose of exposure, do not eliminate the risks due to the relatively necessary exposure time.

Other silver films have a graduated target allowing measurements, but not giving great precision
The silver films can be used only once the device of the invention allows without any change the repetition of taking pictures.

 The device according to the invention overcomes these drawbacks.

 It indeed comprises an imaging system having on the one hand a cathode ray tube restoring the radiographic image, on the other hand an electronic box having for function the digitization of the image, and, of a flexible buccal sensor. The sensor is coupled to a transmitter. The device is started up by a trigger. When the user controls the trigger, the transmitter sensitizes the sensor whose signals are processed by the digital unit which instantly displays the picture on the cathode-ray screen. The. sensor can scan an anatomical surface to allow multiple shots to be taken.

 This device comprising, in combination, non-traumatic emitting and sensor means, also comprises means for controlling these two elements in order to analyze such or such anatomical part, like a tooth in a jaw. The sensor associated with an analog-digital converter, makes it possible to obtain in the form of digital signals a representation of shape on a plane. The digital signals obtained leave the imager with the possibility of improving them by various treatments.

 The device according to the invention makes it possible to capture all the characteristics of the shape of the zone to be analyzed as given by a dental radiography on silver film, with an accuracy which is of the order of 40 microns.

 The sensor and converter used must correspond to the type of waves used by the transmitter. According to a preferred embodiment, the emitter is a controlled source of ionizing rays. The sensor reached by the beam of rays is advantageous of the charge transfer photosensor type, in particular photosensors of the matrix CCD type or even a modified video tube. The interest of the CCD photosensor on the vidicom system comes from its small size and its sensitivity and analysis is done by fixing the coordinates according to two dimensions, for example at points corresponding to intervals of 20 microns.

 According to one embodiment, the sensor and the analog-digital converter deliver the means for processing the "point-by-point" output signals transformed by an interface for their adaptation to the digital processing means, means for viewing captured data, in connection with means for storing the images obtained.

 The visualization should preferably be provided to give the information contained in an x-ray, in order to be able to assess the anatomical state of the target shape. Visualization is particularly advantageous for finding the angles and orientations giving the best quality of data entry. The visualization after analog to digital conversion is also useful to assess the accuracy of the data row by row or column by column. The choice of the best image to retain for subsequent digital processing may be manual and facilitated by interactive visualization, or even be entirely automatic.

 Digital processing, prior to taking a picture, provides means to improve the image (conventional correlation, equalization or other software); means for intervening directly on the stereotype such as annotations or measurements; means for coloring this or that part of the picture.

 The storage of these infoí atioà t treVL rour donrler to the user means of comparison, statistics or archiving of stereotypes. Mass memories like for example, in a nonlimiting way, disks (flexible, hard) or magnetic tapes require a few seconds to get a snapshot.

Electronic memories can instantly restore a preset picture. A printout may freeze the information on a transportable medium.

 In any case, the invention will be better understood with the aid of the description which follows, with reference to the appended schematic file representing, by way of non-limiting examples, some forms of execution of this radiographic digitalization device, with a view to '' get a snapshot in real time, especially in dental technology.

 Figure 1 is a very schematic view of a first embodiment of the transmitter-sensor part of the device according to the invention.

 Figure 2 shows a detail of the sensor head.

 Figure 3 is an overview of the means for taking a picture, according to the principle of Figure 1, in a particular arrangement.

 Figures 4 and 5 are views to show how the sensor can be placed in the mouth.

 FIG. 6 is a flowchart illustrating the operations performed by the transmitter when viewing the photograph.

 Figure 1 shows that for this purpose we can use the transmitter (1) in an e perpendicular to the sensor (2). The beam of ray must cross the zone where is implanted the tooth (3) before meeting the sensor (2). The sensor (2) gives its signals by the flexible connectors (4).

 FIG. 2 represents an exemplary embodiment of the head supporting the photosensor (7). The casing (5) protects the sensor. Lapite envelope (s) can be sterilized. The photosensor (7) is hermetically sealed and obscured by the envelope (5). The flexible connectors (4) can be rotated in all directions and stores the last position given. A connector cover (6) is sliding on the flexible connector (4). In the example, its role is to protect the connetique (4) from the aggression of the teeth leaving the mouth.

 Figure 3 is a representation of a possible figure of all the modules. The transmitter of the conventional type is supported by its foot (8). It is orientable in space. An electrical part (9) interfaces with the control module (13) via an electrical connection (15).

This type of connection is not limiting, it can be carried out by a plastic optical fiber for example. The sensor (2) is linked to the control module (13) by its connectors (4). The general trigger (14) (push or pedal can also be replaced by a speech recognition command, is also connected to the control module (13). The control module (13) is provided with electronic cards ( 10) of a cathode ray tube (11) making it possible to display the picture obtained. A keyboard (12) gives access to the programming of the control module (13) as well as to the image processing which are included in the module (13).

 Figure 6 gives a possible description of a sequence of operations to obtain a snapshot. The image is scanned on at least 30 gray levels. The programming and communication system with the operator must obviously be adapted to the nature of the information processed (numerically defined forms), by making it possible to view, control and save the work. A gateway gives access to other electronic cards which support, for example, an alphanumeric keyboard and function commands.

The software allows to "manipulate" the image: translation, change of scale, rotation, .. The data will be processed in "real time" with the execution of other tasks such as the management of the dental or medical office.

Claims (7)

 1. Device for taking radiographic images in real time, in particular for producing dental radiographic images and even more particularly retroalveolar radiographic images, characterized in that it essentially comprises, in combination, means emitting electromagnetic waves (1) , means for receiving these waves transmitted through the anatomical area (3) to be analyzed, directing said waves on a sensor (2) associated with an analog-digital converter making it possible to obtain in the form of digital signals a representation of the anatomical area in the two dimensions of space and of the means of analysis (13) and of processing of the digital signals obtained, in particular with a view to processing an electronic image observed on a cathode screen (11).  2. Device according to claim 1, characterized in that it comprises an X-ray source produced using a generator (1) orientable as a function of the sensor (2), also directing on said sensor (2) a reference beam.  3. Device according to claim 1 and 2, characterized in that it comprises at least one sensor (2) and a connector (4) for directing the signals transmitted by the sensor (2) to an interface (16) in order to be operated in the following system (13). The CCD type sensor is coated in a sterilizable plastic (5) to be positioned in the mouth (17).  4. Device according to claims 1, 2 and 3 characterized in that it comprises a link which establishes the transmission of signals between the sensor (2) and the interface (16) Said connection allows orientation in the three dimensions of the space making it possible to stabilize a defined position of the sensor (2) in the mouth (17). This sealed connection is provided with a sliding resin bead (6) allowing an occlusal bite in order to protect and fix the device in the mouth.  5. Device according to claims 1, 2, 3 and 4 characterized in that it comprises associated with the system (13) an analog to digital converter which digitizes the signals. The converter is associated with electronics authorizing preprocessing of said signal upstream and downstream of the converter  6. Device according to any one of the above-mentioned claims, characterized in that it comprises a display device for producing a visual representation which can be used by the operator's eye to define a medical diagnosis and controlled therapy.  7. Device according to claims 1, 2, 3, 4, 5 and 6 characterized in that it comprises an electronic assembly associated with software which allow all conventional image processing. In a non-exhaustive manner one can cite the false color definition of dentists, convolution matrices, enlargements, image improvements. Also, this device comprises means for processing the "point by point" output signals for their adaptation to the digital processing means, to the data display and storage means for instant management of the device.