WO1995006434A1

WO1995006434A1 - Method of making stereoradiograms, particularly of the masticatory apparatus, and apparatus for implementing the method

Info

Publication number: WO1995006434A1
Application number: PCT/EP1994/002915
Authority: WO
Inventors: Franco Dal Pont
Original assignee: Franco Dal Pont
Priority date: 1993-09-03
Filing date: 1994-09-02
Publication date: 1995-03-09
Also published as: ITVE930025A1; AU7693494A; ITVE930025A0

Abstract

A method of making stereoradiograms, particularly of the masticatory apparatus, characterized in that two flat radiograms angled between them are carried out on the structure to be examinated and then these flat radiograms are elaborated to obtain a stereoradiogram. An apparatus for implementing the method is used comprising two X-ray sources (2, 2') positioned before the structure (4, 22) to be examined, and able to give couples of flat radiograms of this according to two angled directions, and means (10) for tridimensionally processing these two different flat radiograms.

Description

METHOD OF MAKING STEREORADIOGRAMS, PARTICULARLY OF THE MASTICATORY APPARATE AND APPARATUS FOR IMPLEMENTING THE METHOD

The present invention relates to a method of making stereoradiograms, particularly of the masticatory apparate and an apparatus for implementing the method.

At present the most advanced procedures for obtaining images of internal structures of the masticatory apparate utilize the Computerized Axial Tomografy (TAC) or the Nuclear Magnetic Resonance (RMN) . From the point of view of the result, with regard to the tested structure, the TAC as well the RMN give certainly a great deal of informations, from which it is possible to evaluate the density, the thickness and the morphology of the structure itself. Nevertheless the TAC is an invasive procedure and both require extremely sophisticated and expensive equipments.

An aim of the invention is to obtain stereoradiograms of the structures of the masticatory apparate using apparatus simple and widely disposable on the market.

A further aim of the invention is to obtain stereoradiograms with a not much invasive apparatus.

A further aim of the invention is to obtain stereoradiograms of moving structures.

A further aim of the invention is to obtain images being qualitatively suitable for computerized tridimensional elaboration.

All these aims and others that will result from the following description are reached according to the invention through a method of making stereo-radiograms, particularly of the masticatory apparate, as described in claim 1.

To implement the method an apparatus is used as described in claim 7.

The present invention is hereafter further clarified in two preferred embodiments with reference to the enclosed drawings, in which: Figure 1 shows a schematic plan of an apparatus for implementing the method according to the invention. Figure 2 shows in partial and enlarged plan view an apparatus in a second embodiment for implementing the method.

Figure 3 shows in a frontal view a support structure for a Xray equipment in a particular embodiment of the apparatus according to the invention. Figure 4 shows it according to the lateral view IV-IV of figure 3, and

Figure 5 shows it according to the plant view from bottom V-V of figure 3. As it may be seen from the drawings the apparatus according to the invention comprises, in a first embodiment, two Xray equipments 2,2' or an Xray equipment with two distinct sources, facing for example a tooth 4 of the lower jaw to be examined and with their axis arranged with an angle of about 6°. Opposite to the tooth 4, namely inside the oral cavity, a sensor of image is placed, for instance a CCD (Charge Coupled Device) .

The sensor 8 is connected via cable to a computer 10, linked at its turn to a display 12, to a printer 14 and to a recorder 16.

It is foreseen that the two Xray equipments 2,2' are operated one after the other, in order that in the same sensor 8 the images related to both the Xray sets are formed successively. Likewise it is foreseen that the screen 12 of the computer 10 is divided into two parts, in which the two images are formed side by side.

In this case the observer can elaborate with its brain the two flat images and blend them into a tridimensional image.

It is anyway advisable that this tridimensional elaboration of the two flat images is made by the computer 10 that provides in this case a single tridimensional image to be directly seen on the screen 12 and, if required, to be printed and/or recorded.

Instead of using a single sensor 8 receiving successively the radiations coming out from the two Xray equipments, it is possible to use two distinct sensors 8,8' receiving with continuity the radiations of the related Xray equipments 2,2', and therefore they do not require an alternating operation. In this case it is convenient that each sensor has such a shape to exclude the radiations coming out from the Xray equipment of the other sensor. This can be obtained, for instance, as shown in Fig. 2, where the examined structure is the temporal joint 22, mounting each sensor on an angled support 18,18', provided with a wing 20,20', parallel to the direction of the radiations coming out from the related Xray equipment 2,2' and extending towards the same as much to screen the related sensor 8,8' from the radiations coming from the other Xray set 2' ,2.

Instead of using two Xray equipments it is possible to use only one equipment mounted on a structure allowing proper movements from one position to the other after have done the first Xray.

An example of this structure is shown in figures 3 to 5. It comprises a support 24, essentially C-shaped, fixed to a traditional suspension member 26. In the lower horizontal arm 28 of the C-shaped support, a curved guide 30 is obtained, having the curvature center in the sensor (not shown in the drawings) . In this curved guide 30 a slide 32 is sliding, to which a pneumatic actuator 34 is applied, whose cylinder is fixed to a bracket 36 supporting the Xray equipment 2, and whose rod has an end pivotally connected to a connection element 38, fixed to the vertical arm of the C-shaped support 24. When operated the actuator 34 is fed alternately in both directions synchronously with the Xray equipment 2 and with the sensor of image, so as to cause their activation only when the Xray equipment 2 is placed in one of the two extreme positions, defined by two screws 42, limiting the angular stroke of the Xray equipment 2 to an extent of about 6°, which is considered as an optimal in the most of the cases. Obviously for particular requirements it may be convenient to modify this angle, and this can be carried out by acting on said screws 42. When required, it is also possible to examine moving structures, by means of two Xray equipments working in alternance and acting on a single sensor that operates, with the same alternance, the two distinct parts, into which the screen of the display 12 is divided. Obviously it is also possible that these two moving images are elaborated by the computer giving on the screen a single tridimensional moving image. Also in the case of an apparatus including two Xray equipments and two distinct sensors it is possible to obtain images of moving structures. In this case, although being not necessary the alternating operation of the two Xray equipments, the resulting intermittence could be favourable in reducing radiation quantity.

In any case, independently from the used apparatus, from the visualization device and from the elaboration system of the flat images being chosen, it is possible to obtain a stereographic image of the examined anatomical structure. This allows:

- to observe in the space the anatomic structures and their exact morphology, and to put in evidence their occasional pathology,

- -to place marks on the outer side of the structure for measuring purposes,

- to obtain these advantages with a simple, moderately expensive and not much invasive equipment,

- to obtain, thanks to the tridi ensionality of the image, a -. 1 -

better definition and contour sharpness,

- to have an overall view of the examined structure, with better opportunity to consider the situation, and

- to obtain stereoradiograms of moving structures.

,

Claims

C L A I M S

1. A method of making stereoradiograms, particularly of the masticatory apparate, characterized in that two flats radiograms angled between them are carried out on the structure to be examinated and then these flat radiograms are elaborated to obtain a stereoradiogram.

2. A method according to claim 1 characterized in that each Xray image is formed on a sensor, which converts it into an electric signal to be sent to a computer for its processing.

3. A method according to claim 2 characterized in that the two flat radiograms are taken on the examined structure by means of two distinct Xray sources acting in different times on a single sensor.

4. A method according to claim 2 characterized in that the two flat radiograms are taken on the examined structure by means of a single Xray source that is moved into two differently angled positions to act in subsequent times on a single sensor.

5. A method according to claim 1 characterized in that the two flat radiograms are taken on the examined structure by means of two distincts Xray sources acting independently and exclusively on respective distinct sensors.

6. A method according to claim 5 characterized in that a succession of radiograms are made on the structure to be examined in order to obtain a stereoradiogram of the structure while moving.

7. An apparatus for carrying out stereoradiograms, particularly of the masticatory apparate according to one or more of the claims 1 to 6 characterized in that it comprises two Xray sources (2,2') positioned before the structure (4,22) to be examined, and able to give couples of flat radiograms of this according to two angled directions, and means (10) for tridimensionally processing these two different flat radiograms.

8. An apparatus according to claim 7 characterized in that it comprises at least one sensor (8,8') able to turn into electrical signal the flat radiogram formed on it, and a computer (10) connected to said sensor (8,8'). to receive the signal and turn it, after its elaboration, into a stereoradiogram of the structure (4,22) to be examined.

9. An apparatus according to claim 8 characterized in that it comprises two distinct Xray sources (2,2'), acting in different times on a single sensor.

10. An apparatus according to claim 8 characterized in that it comprises a single Xray source (2) displaceable between two angled positions and cooperating with a single sensor (8) facing said source according to the two angled positions.

11. An apparatus according to claim 10 characterized in that the Xray source (2) is slidable along a curved guide (30) provided on a fixed support structure (24) and having the curvature center on said sensor.

12. An apparatus according to claim 11 characterized in that ' the fixed structure (24) is C-shaped and supports a pneumatic actuator (34) having a part connected to said structure (24) and another part connected to a slide (32) sliding along said curved guide (30) and fixed to said Xray source (2) .

13. An apparatus according to claim 12 characterized in that adjustable ends of stroke elements (42) are applied to said fixed structure (24) to limit the extreme angular positions of said Xray source (2) with respect to said structure.

14. An apparatus according to claim 8 characterized in that it comprises two distinct fixed Xray sources (2,2') acting independently on two distinct sensors (8,8') each of them provided with means (20,20') to screen the source of the other sensor (8' ,8) . is. An apparatus according to claim 14 characterized in that each sensor (8,8') is mounted on an angled support (18,18') with a wing (20,20') turned toward the related Xray source (2,2') and extending so as to screen the related sensor from /06434

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the radiations coming out from the other Xray source (2',2). 16. An apparatus according to claim 11 characterized in that the two units including one Xray source (2,2') and the related sensor (8,8') are connected to a circuit providing their alternative operation.