DE102009060020A1 - Cassette for a storage film, a storage film for use therewith, a device for reading a storage film, an examination device with such a cassette, and a method for capturing panographic images - Google Patents

Abstract

A cassette (14) for the panography is specified, which can accommodate a plurality of image plates (46, 48, 50) in a shape adapted to the geometry of the jaw. A support plate (36) of the cassette (14) can be individually adjusted elastically or plastically to the shape of the jaw being examined.

Description

The invention relates to a cassette for a storage film, a storage film for use in such a cassette, a device for reading such a storage film and an examination device which operates with such a cassette and a storage film.

In dentistry, mainly two types of X-ray images are taken, namely intraoral images and panoramic images. In the panoramic images, the image carrier (classical X-ray film or storage film) is exposed through the skull, whereby the image geometry ensures that only the areas of interest of the skull, namely the jaw, are sharply imaged, while the other parts of the skull become a homogeneous background to lead. However, since the X-rays traverse the skull entirely, more X-ray radiation is absorbed by the body than in an intraoral recording, in which the X-ray rays only pass through the area of the jaw to be examined.

It was therefore attempted in earlier years, to arrange a small X-ray source inside the mouth, which radiates into a (relative to the Antikathode) rear half-space (ie to the back of the two jaws), then around the outside of the jaw around an extensive X-ray film is placed, which is exposed at the same time in all places by the emitted backward X-ray radiation. This type of X-ray imaging, known as panography, makes it possible to record the entire upper jaw and lower jaw with one image.

This method has increasingly disappeared since 1980 et seq. Because the x-ray tubes inserted into the mouth had an operating voltage of only about 55 kV, with the beam current at 1 mA. Under such operating conditions, one has a high portion of the spectrum of the tube at low energies, which ultimately results in the skin being over-stressed.

A general disadvantage of the panography method is that the image is heavily distorted due to the use of a point light source, so that the evaluation of the X-ray image requires special experience. On the other hand, it was advantageous in panography that the image was sharper with the same film material as compared with that obtained with conventional panoramic images as long as magnification factors below 1.5 were used.

Meanwhile, x-ray sources that can be inserted into the mouth have been developed that can be used in the range between 50 and 70 kV with currents of 0.1 mA and smaller. With such X-ray tubes, in which the spectral component is reduced at low energies, the burden on the skin can now be kept smaller. The focal spot is less than 0.1 mm. Typical exposure times are between 0.1 and 5 sec. This ultimately allows a resolution of 5 line pairs per mm, with which caries is detectable by Rötgenuntersuchung.

The present invention is intended to provide a cassette which allows the easy use of exposable pieces of material for the purposes of panography, in such a way that the exposable piece of material is curved approximately in accordance with the jaw profile.

The invention further provides a storage film which is particularly suitable for use in such a cassette.

By the invention, a device is also to be specified, with which storage sheets that are used in the cassettes of the invention can be read.

The invention is also intended to specify a panography examination device.

These objects are achieved by a cassette having the features specified in claim 1, by a storage film having the features according to claim 26, by a read-out device according to claim 32 and an examination device according to claim 39.

Advantageous developments of the invention are the subject of dependent claims.

In a cassette according to claim 2, the basic shape taken in the unloaded state roughly corresponds to the course of a jaw. So there are only minor adjustments to the geometry of each individual individual jaw to be recorded.

The development of the invention according to claim 3 allows to easily take into account a large number of jaw shapes.

In a cassette according to claim 4, the support member is retained after an adaptation deformation in the respective selected geometry.

In a cassette according to claim 5, the support member can be repeatedly adapted to different jaw shapes.

Even with the development of the invention according to claim 6, it is possible to adapt a support member specifically to the shape of a jaw. A cassette with a support member according to claim 6 is characterized by a particularly long life.

A certain elastic bias of the holding part results already from the fact that the exposable material pieces used in the holding part have their own elastic flexibility, which may well be significant, especially if one places a plurality of such exposable material pieces one behind the other.

With the development of the invention according to claim 7, a geometry adjustment of the support member for the exposable material piece is obtained in a simple and reproducible manner. In this case, the specified in claim 7 locking device is characterized by a particularly simple mechanical structure.

In a strut-locking device according to claim 8, one can bring about the locking in a simple manner. It only needs a single clamping handle to be operated.

In a cassette according to claim 9, each set geometry of the support member can be characterized by a few numbers. These can be z. B. are entered into a computer to inform them about the respectively set shape of the support member.

The development of the invention according to claim 10 makes it possible to easily take into account the fact that jaws typically have a more curved front portion and a less curved lateral portion. This results automatically by the different bendability of the various sections of the support member that they are deformed differently when exercising a force acting on them alike.

In this case, in a cassette according to claim 11, a continuous change in the curvature of the support member is obtained.

In a cassette according to claim 12, one can perform the actual support member as a plate with a constant thickness and obtain the different flexibility of the different plate sections, characterized in that on the plate a reinforcing rib is placed, the cross section changes.

The development of the invention according to claim 13 is in view of a simple releasable connection between the piece of material and the supporting part of advantage.

It is obtained with the development of the invention according to claim 14, a forced positioning of the exposable piece of material along its entire longitudinal edge, and by moving the retaining strip, the exposable piece of material can be easily released.

The development of the invention according to claim 15 is advantageous in view of the fact that no additional bending stiffness is caused by the retaining strip.

In a cassette according to claim 17, the retaining strip can be twisted under elastic deformation so that the exposable piece of material is released from it.

Alternatively or additionally, the retaining strip may additionally comprise pivotable retaining lugs, which are movable against spring force in a position releasing the storage film.

The development of the invention according to claim 19 is advantageous in terms of making the support member as a cheap wearing part, possibly also as a disposable item.

The development of the invention according to claim 20 allows hindurchzustecken the anticathode containing tubular portion of an intraorally positionable X-ray source through the support member. In this way, support member, carried by this exposed exposable piece of material and X-ray source are combined into one unit.

According to claim 21 obtained in a simple manner, a light-tight envelope for the exposable piece of material.

In this case, the development of the invention according to claim 22 in terms of low cost of the protective case of advantage.

If the protective cover is closed in a light-tight manner as specified in claim 23, then this closure can also be carried out in a dental practice or at another place of use without major skills.

In a cassette according to claim 24, a hygiene part is connected to the protective cover of the cassette, which surrounds the intraoral positionable housing part of the X-ray source, when the unit formed by this housing part and the cassette is positioned on the patient's jaw.

The development of the invention according to claim 25 makes it possible to customize each cartridge. This individualisation may relate to the number and type of exposable pieces of material contained in the cassette, but in particular also relates to the geometry of the supporting part used for panography. The corresponding data can be stored in a memory and retrieved from a computer used in reading the latent image of the exposable piece of material on the basis of the identification in order to make correction calculations, evaluations and presentation conversions on the recorded image.

The development of the invention according to claim 26 makes it possible to expose different pieces of material simultaneously. In this case, one can then use pieces of material of different resolution and / or sensitivity and thus produce panographic images with a single exposure, which are adapted to different circumstances of the structure to be examined.

The development of the invention according to claim 27 is advantageous in view of the fact that the geometry of the piece of material, which is used for recording, can be chosen the same during exposure and reading. This allows, in principle, to install the piece of material firmly in the cassette and to read lying in the cassette. Only when replacing a worn piece of material with a new one does the piece of material need to be removed from the cassette and a new piece of material reinserted into it. Due to the fact that the piece of material remains in the cassette during normal operation, its wear is reduced.

If a storage film according to claim 28 is used in conjunction with a cassette according to the invention, then the intraorally positionable tubular portion of the x-ray source can simply be inserted through the storage film.

In this case, it allows the development of the invention according to claim 29, to insert the exposable piece of material laterally in the support member. Such introduction of the piece of material is particularly simple, since the piece of material automatically moves into the desired geometry with advancing in the holding part. The slot enabling this is located at the same level as the intraorally positionable tubular housing part of the X-ray source. Since the latter must lie between the teeth of the jaw, there are usually no teeth or jaw sections to be imaged in the region of the slot provided according to claim 29.

Even with the development of the invention according to claim 30, it is possible to bring the exposable piece of material by moving in the desired position, wherein only in the region of the passage opening for the X-ray source is no photosensitive material.

With the development of the invention according to claim 31 ensures that there is no gap at the joint hiss the film segments.

In a device according to claim 32, the detection of the geometry of the cassette is done by machine.

In a device according to claim 33 one can visually evaluate the respective curvature of the support member in a simple manner. The recording of the shape of the support member by a camera is preferably carried out after reading the exposable piece of material or after its removal. The shape of the support member can be particularly simple and accurate determine after removing the protective cover.

Again, the use of a camera as specified in claim 33, particularly advantageous because their image can be evaluated very easily on curved structures.

A similar advantage is obtained according to claim 34 with regard to the machine readout of the identification of a cassette.

With regard to a simple implementation of the panography, it is particularly advantageous if the reading of the exposable material piece takes place in the same geometry of the piece of material as its exposure. Since the exposable piece of material is adapted to the shape of the jaw, the use of a single scan head with revolving readout beam would result in greatly different readout conditions in the different areas of the piece of material.

With the development of the invention according to claim 35 is achieved that in different areas of the exposable piece of material has substantially the same read-out conditions, although the geometry of the exposed piece of material is not cylindrical.

In a device according to claim 36 has a very good resolution with a total of even less number of scan heads used.

With the development of the invention according to claim 37 is achieved that the latent image is read out under substantially the same amount of the readout light at the different pixels.

If, instead, one wishes to work with a constant scanning angular velocity, it is also possible to adapt the intensities of the readout light sources of the different scan heads, if necessary adjust them path-dependent, so that each pixel of the latent image is read out with the same dose.

A device according to claim 38 is also characterized by easy handling. There are no significant mechanical adjustments to make.

With the development of the invention according to claim 39 is achieved that there is no crosstalk of fluorescent light when working the different scan heads.

A device according to claim 40 also makes it possible to read a piece of material, which is better adapted to the course of a jaw in its geometry than partially cylindrical geometry, with substantially the same read-out conditions for the different pixels of the piece of material. Thus one obtains in a simple way a successive structure of the different image lines or image columns.

In a device according to claim 41, only a single scan head is needed, which is placed at different locations, depending on which area of the exposed piece of material is read out. This switching of the scan head in different working positions according to claim 41 only a few positions.

An apparatus according to claim 42 makes it possible to record a structure to be examined in different planes and under different projection conditions. The respective conditions are easily predefined by the markings of the mounting device.

Sometimes it is advantageous to do a small-format intraoral recording together with a larger-format panoramic image. This can be done with a device according to claim 43 in a very simple manner.

The preferred device according to claim 44 makes it possible to apply only parts of the rear half-space with X-rays in which a recording is desired. By different caps and different placement of caps in different axial position and different angular position you can adjust the area exposed to X-rays in a simple manner.

In an examination apparatus according to claim 45, the photosensitive material piece may always remain in the same curved shape. As a result, fatigue fractures but also wear marks on the surface are avoided.

In an apparatus according to claim 46, the capture of panographic images is particularly simple, since the scanning of the latent image of a memory film piece can take place directly at the location of the recording. All you have to do is to move the imaging plate used for recording over the geometry of a geometry in which it was located during the recording, over a reading gap of the scanner. This can also be done by moving the cassette carrying the storage film directly over the reading gap of the scanner.

Where it is not possible to arrange a receiving station comprising the cassette and a scanning station axially one behind the other, one can according to claim 47 provide a transport device which brings the cassette in a defined manner from the receiving position to the scanning unit. Such a transport device can, for. B. include a linearly movable carriage or a pivot link assembly.

The method given in claim 48 makes it possible to produce panographic images corresponding to different layers of the structure to be examined.

The same advantage is obtained by the method specified in claim 49.

With the development of the invention according to claim 50 it is achieved that with good cost / benefit ratio, the respective properties of the receiving device and the scanning device of the examination apparatus used are used.

The procedure specified in claim 51 facilitates operation of the examination device and avoids errors in the making of settings that otherwise have to be made on the examination device to take into account special properties of the storage film used.

With the method specified in claim 52 images are obtained, which are particularly easy to visually assess the viewer.

The invention will be explained in more detail with reference to the drawing with reference to the embodiments. In this show:

1 a partially sectioned plan view of a panography examination device with an intraoral positionable X-ray source and a cassette for imaging plates;

2 a supervision of the in 1 shown unit from the patient side;

3 an enlarged plan view of a section of a retaining strip, the part of a storage film support member of the examination device according to 1 is;

4 a plan view of a modified embodiment of a storage film support member together with an intraoral positionable X-ray source;

5 a schematic block diagram of an apparatus for reading a panographic storage film and for processing the read image in dependence on the geometry of the storage sheet;

6 a schematic plan view of a device for reading a storage sheet in the geometry in which it is used for a panography recording;

7 a side view of a tubular end portion of an intraoral positionable X-ray source with an attached aperture cap;

8th a plan view of a modified storage film for use in panography;

9 a view of a further modified memory sheet for the panography, which consists of two parts assembled flush;

10 a similar view as 9 in which, however, the adjacent sections of composite foil segments overlap;

11 a side, partially vertical sectional view of an examination apparatus for making panographic images, the jaw of a patient; and

12 a Schamtic representation, which explains the conversion of a panographic image of a jaw into a panoramic image.

In the 1 to 3 is a panography examination unit in total with 10 designated. It includes an X-ray source 12 and a cassette unit 14 that is detachable to the X-ray source 12 is attached.

The x-ray source comprises a housing 16 with a rear cuboid housing section 18 and a slender tubular front housing section 20 , In the rear housing section 20 is an electron gun 24 arranged, which is an electron beam 26 which centrally through the tubular housing section 20 passes through and at the end of an anticathode 28 incident. When braking the electron beam 26 on and in the Antikathode a Röntenstrahlung arises, as with 30 indicated schematically. This will be in the posterior half-space of the anticathode 28 issued.

The material from which the housing section 20 is transparent to X-rays, opaque to visible light, e.g. B. a metal with a low atomic number.

at 32 is a power supply for the X-ray source 12 indicated.

The cassette unit 14 includes a hub part 34 , on which side and up and down running a support plate 36 is shaped. The support plate 36 is in check settlement and the hub part 34 lies at the middle of the rectangle.

Seen from above has the support plate 36 in the unloaded state from the 1 apparent form that approximates the shape of a human jaw.

Along its upper and lower edges is the support plate 36 each with a retaining rail 38 respectively. 40 provided that has rectangle U-shaped cross-section as out 2 seen. The retaining rails 38 and 40 each have a base section 42 , which is perpendicular to the main surface of the support plate 36 runs, as well as a front leg 44 which points to the horizontal center plane of the cassette unit under the conditions of use 14 tapers. This center plane corresponds to the plane of the drawing 1 ,

The distance of the thigh 44 from the front of the support plate 36 , ie the width of the base section 42 is chosen so that three memory sheets 46 . 48 . 50 lying one behind the other with their upper and lower ends in the support rails 38 . 40 Find recording.

The memory foils 46 . 48 . 50 may differ in resolution and / or sensitivity to produce images of different diagnostic value with a single exposure. The memory foils 46 . 48 and 50 but they can also be identical. One then uses the in these memory foils 46 . 48 . 50 held images to add these pixel by pixel additive to get an overall picture with better signal-to-noise ratio.

In modified retaining rails, the base portion 42 to be smaller or larger, to to record fewer or more imaging plates and possibly additional absorber foils.

The memory foils 46 . 48 . 50 each have a central opening 52 that the hub part 34 can record.

How out 3 As can be seen, the base sections 42 and the thighs 44 with wedge-shaped recesses 54 provided to the support rails 38 . 40 together with the support plate 36 to be able to bend.

How out 2 Obviously, have the thighs 44 other lower recesses 56 , between which retaining lugs 58 remain.

The support plate 36 and the retaining rails 38 . 40 are molded from an elastically deformable plastic material, so that the upper edges of the retaining lugs 58 under the upper or lower edge of a storage film 46 . 48 . 50 can be pressed to remove or insert a storage film can.

The cassette unit 14 also includes a total of 60 designated protective cover, which by a rear wall 62 as well as a front wall 64 is formed. Rear wall and front wall are made of a pigmented plastic material, so that the protective cover 60 is tight against visible light.

How out 1 visible, have back wall 62 and front wall 64 in the area of reduced diameter sections having 66 . 68 of the hub part 34 cylindrical protuberances 70 . 72 which are press fit on the reduced diameter sections 66 . 68 are set up. Alternatively, they can also be welded or glued there.

At the edges are back wall 62 and front wall 64 by longitudinal welding 74 . 76 and transverse welds 78 . 80 connected.

At the hub part 34 is an upper bite plate 82 and a lower bite plate 84 formed. In the area of Aufbeißplatten 82 . 84 have the back wall 62 and the front wall 64 corresponding prismatic protuberances (not shown), so that the Aufbeißplatten 82 . 84 inside the protective cover 60 are located.

The bite plates 82 . 84 can on their top and / or bottom with visual and / or tactile perceptible markings 85-1 . 85-2 etc. be provided. In this way, it is possible in a patient, the X-ray source 12 to arrange in different precisely predetermined positions inside the mouth of a patient and set the same relative position between the X-ray source and jaw in different patients. For each of these positions one obtains in the first case an image with slightly different projection conditions, in particular different magnifications. From various such images one can computationally create layer images. In the second case, one has the same projection geometry in different patients.

The tubular housing section 20 the X-ray source 12 is from a closed at the free end cylindrical hygiene part 86 surrounded, which also on the hub section 68 can be pressed, shrunk, glued or welded.

This is the result of the X-ray source 12 and the cassette unit 14 formed examination unit 10 light-tight and fluid-tight sheathed.

On the outside of the support plate 36 can (as in the left half of 1 indicated) a metal rail 88 be placed, which is made of a metal which can be plastically deformed several times without breaking. So that the support plate 36 , which is already adapted to an average jaw from home, taking into account the particular requirements of an individual jaw so bent that the support plate 36 and thus also the memory foils she holds 46 . 48 . 50 parallel to the outside of the jaw.

4 shows an alternative way of adjusting the geometry of the support plate 36 , Components of the examination unit 10 To help understand the adjustment of the geometry of the support plate 36 are not necessary are in 4 omitted. It is also shown only half of the cassette unit, the other is mirror-perfect.

One recognizes in 4 one on the back of the support plate 36 attached stiffening rib 90 whose cross-section with increasing section from the axis of the X-ray source 12 increases. In the present case, the increase in cross-section is chosen so that in to the main surface of the support plate 36 vertical direction. In addition or instead, a cross-sectional increase in to the plane of 4 Provide vertical direction.

The stiffening rib 90 has bearing openings at two spaced locations 92 . 94 , each one a pivot pin 96 respectively. 98 can pick up from the end of a control rod 100 respectively. 102 worn. The control rod 100 passes through a cutting guide 104 standing in a warehouse block 108 is provided. The storage block 108 sits slidably on a support plate 110 , which (here on the housing of the X-ray source 12 ) mechanically fixed to the hub part 34 connected is.

The storage block 108 is in his in 4 above the support plate 110 Slit lying section and thus has two clamping plates, one of which at 112 is shown. In the clamping plate 112 is a threaded hole 114 provided, while the upper clamping plate, not shown, has a through hole, which with the threaded bore 114 flees. In this way, the two clamping plates can be adjusted in their distance by a screw and the control rod 104 , which preferably has rectangular cross-section, clamp between them.

The control rod 102 is in a warehouse block 116 led, over stubby waves 118 rotatable in a carriage 120 is stored on the support plate 110 is displaceable. The storage block 116 is slotted again to the control rod 102 to lock in the set position.

The adjusting rods 100 . 102 each wear a scale 122 attached to the end face of the associated bearing block 108 respectively. 116 is read.

By the locking device described above, the course of the support plate 36 upon release of the adjusting rods 100 . 102 be set and then fixed in its shape by the clamping devices of the two bearing blocks are tightened.

About the cross-sectional profile of the stiffening rib 90 can be specified how strong the support plate 36 can be adjusted in different areas.

In 5 is schematically a scanner 124 shown the memory foils 46 . 48 . 50 can read out one after the other.

Image plates comprise a photosensitive layer containing, dispersed in a matrix, phosphor particles provided with color centers. At finished color centers there are local electronic excitation levels that can be activated by X-rays and have long lifetimes ranging from 15 minutes to one hour.

If excited such color centers are irradiated with a laser beam which is red in practice, the color centers are raised to a higher excited state and relax therefrom, emitting blue fluorescent light. By photoelectrically registering the fluorescent light of each pixel of the storage film, it is thus possible to convert the latent image of the examination project generated by the X-rays into an electrical image which can be digitally processed and converted. Such conversion allows, in particular, the conversion of the less familiar panography representation into a panorama representation.

In 5 is at 126 a laser showed a fine red laser beam 128 provides. This laser beam is only schematically reproduced mirror 130 . 132 on an axis 134 brought to the scanner. A deflection prism runs around this axis 136 around which the laser beam 128 deflects in a transverse Ausleseebene in which he then according to the position of the Umlenkprismas 136 circulates.

The memory to be read 46 . 48 or 50 is on a transparent cylinder 138 placed and on this by three drive belts 140 . 142 . 144 moved in the axial direction.

The drive belts 140 . 142 . 144 are mechanically coupled, as indicated by dashed lines, and are driven by a stepper motor 146 powered by a rotary encoder 148 cooperates.

A large diameter photomultiplier serves to catch the fluorescent light 156 that of an annular mirror 158 is surrounded. Above the drawing level of 5 lying another mirror is to think of the clear cross-section of the cylinder 138 also completed.

The output signal of the photomultiplier 156 is via an amplifier 160 to an input of a process computer 162 given.

The process computer 162 receives at a further input the signal of the rotary encoder 148 and the signal of another encoder 164 that with an electric motor 166 is coupled, which the deflection prism 136 rotating at high frequency.

The process computer 162 also controls the stepper motor 146 and the electric motor 166 ,

Furthermore, the process computer controls 162 an electro-optical shutter 168 with which the laser 126 emitted light can be quickly switched on and off, as will be described in more detail later.

A camera 170 is provided to each set geometry of the support plate 36 to capture and to the process computer 162 reporting it.

A brand reader 172 serves one, the cassette unit 14 characterizing brand 174 read. Under an identifier corresponding to the bar code of the brand 174 corresponds, are in the process computer 162 Stored data indicating the number and type of memory sheets used. If attenuator foils lying between the storage foils are used during the recording, the corresponding data are likewise stored under the identifier corresponding to the mark.

On the output side is the process computer 162 Controlling with a high voltage device 176 connected, which for operating the photomultiplier 156 provides necessary operating voltage.

For entering data is the process computer 162 with a keypad 178 connected.

An output of data and the output of control messages is via one with the process computer 162 connected monitor 180 possible.

The process computer is used to save read-out images 162 with a mass storage 182 connected, and a printer 184 can be used to output images, recording logs, and so on.

At the in 5 The reading device shown, the shape of the reading memory to the shape of the transparent cylinder 138 customized. The laser beam 128 thus applies to all pixels perpendicular, and the geometric ratios of the readout are constant across the image.

For some applications, it would now be advantageous if one could read the memory film in the same geometry in which it was exposed.

6 shows a corresponding reader. Components already described with reference to the preceding drawings are again given the same reference numerals, although they differ in detail.

Some components necessary for understanding the readout device 6 are not necessary are also omitted.

In 6 is a storage foil 46 shown permanently or by arrangement on a support plate has a geometry adapted to the shape of a special jaw. The overall geometry is obviously not circular. But you can put the readout surface of several, here three, partially cylindrical surfaces.

A first part-cylindrical surface extends over an angular range W1, which is symmetrical to the longitudinal center plane of the storage film 46 is. A second angle range W2 adjoins the end of the angular range W1 on the right in the drawing and extends to one free end of the storage foil 46 , Symmetrically to the angular range W2, a third angle range W3 is provided, which extends from the end of the angular range W1 on the left in the drawing to the left-hand free end of the storage foil 46 extends.

The angular ranges W1, W2 and W3 correspond to axes of curvature 134-1 . 134-2 . 143-3 ,

On each of these axes of curvature is now a deflection prism 136-1 . 136-2 and 136-3 provided, which is a laser beam 128-1 . 128-2 and 128-3 substantially perpendicular to the associated portion of the storage sheet 146 directed. The laser beams 128-1 . 128-2 and 128-3 be of lasers 126-1 . 126-2 and 126-3 generated and over mirror 130-1 . 130-2 and 130-3 such as 132-1 . 132-2 and 132-3 directed to the respective axis.

For turning the deflecting prisms 136-1 . 136-2 and 136-3 are electric motors 166-1 . 166-2 and 166-3 provided with resolvers 164-1 . 164-2 and 164-3 are provided.

The interconnection of the various lasers, drive motors for the deflection prisms and resolver is analogous as above in connection with 5 explained in detail.

The control is roughly speaking in detail as follows:
The electric motors 166-1 . 166-2 and 166-3 Run specifically synchronized to each other. Roughly speaking, the product of the angular velocity of the deflection prism and the distance of the prism axis from the associated region of the storage film is constant. This means that the laser beams 128-1 . 128-2 and 128-3 at the same web speed over the storage film 46 be guided. Only one of the laser beams is active at a time 128-1 . 128-2 and 128-3 , which by appropriate control of the electronic locks 168-1 . 168-2 and 168-3 through the process computer 62 is ensured.

For the present embodiment, it is assumed that for scanning a line of the storage sheet 46 first the laser beam 128-3 is activated, from the moment when he on the left end of the storage film 46 hits until the moment when the end of the angular range W3 is reached. This is done via the resolver 164-3 supervised.

And then the laser beam 128-1 reaches the left end of the angular range W1, which is the output of the resolver 164-1 is detected, the laser beam 128-1 by opening his electronic lock 268-1 active and scans the angle range W1 from the left to the right end. Then the laser beam becomes 128-1 by closing his lock 168-1 switched off.

And now the deflection prism 130-2 reaches the position in which the laser beam 128-2 is in the drawing, the upper end of the angular range W2, the electronic shutter 168-2 opened and the remaining part of the scan line is from the laser beam 128-2 left.

It can be seen that in the manner described above, the storage film 46 is read under substantially constant conditions, both in terms of the angle of incidence and as regards the dose of the readout light.

To detect the fluorescent light, there are now three photomultipliers 156-1 . 156-2 and 156-3 provided equally via amplifiers (not shown) to the process computer 152 are connected. The output signals of the three photomultipliers 156 are summed. The photomultiplier 156 are in a mirror plate 158 let in, and this is again (above the drawing level of 6 to think) a fully mirrored plate opposite.

It can be seen that in this way a high-resolution image can be obtained even under read-out conditions which are close to the exposure conditions.

At the in 6 By solid lines reproduced embodiment, three by the process computer 162 used synchronized scan heads, each comprising a laser and a deflection prism.

Alternatively you can, as in 6 dashed lines, also use only a single scan head, one after the other on the three axes of curvature 134-1 . 134-2 and 134-3 puts. For this you can use the parts of the scan head on a slide 186 then put that through an X-drive 188 and a Y-drive 190 is adjustable.

In this case, then the angle ranges W1, W2 and W3 are scanned for all axial positions, and then the carriage 186 moved to the next work position. The corresponding partial images are then joined together electronically to form an overall picture.

For some applications, it is not necessary to completely x-ray the full arches of the mandible and maxilla. For partial images of the mandibular arches can be on the intraoral positionable tubular housing section 20 the X-ray source a shielding sleeve 192 put on. By the axial extent of which one can vary the opening angle of the X-ray beam generated in the back space. If you put the shielding sleeve 192 with a clipping 194 , you can also X-ray certain lateral sections of the mandibular arch.

In the panography apparatus described above, the imaging plates were 46 . 46 . 50 first in the cassette unit 14 inserted, with the openings provided in them 52 axially over the hub part 34 and if necessary the Aufbeissplatten 82 . 84 be pushed. This pushing is done in the axial direction of the housing section 20 until the memory foils 46 . 46 . 50 under elastic deformation of the retaining lugs 58 ultimately in the support rails 38 . 40 lock.

For some applications, it is advantageous if you use the storage film 46 . 46 . 50 from the side into the cassette unit 40 can introduce.

For this one can according to 8th in the storage film one to the one edge open slot-shaped opening 52 provide. In the area of the opening 52 then, of course, no X-ray can be recorded, but this is acceptable for many applications, since the hub part 34 the teeth of lower jaw and upper jaw anyway anyway spaced.

If you want the advantage of lateral insertion of the imaging plates 46 . 46 . 50 receive, but still produce a full Panographiebild, you can according 9 the storage foil 46 in two segments 46A and 46B subdivide, which abut at the center of the storage film.

10 also shows a storage foil 46 with two segments 46 and 46B , These two segments look similar to the memory film 8th , The slot 52 but is significantly shorter, and it uses two rotated 180 ° against each other memory sheets to create a continuous photosensitive surface, which has a receiving opening 52 for the hub part 34 the X-ray source 12 contains.

The segments 46 and 48 After a horizontal pulling apart, a scanner can then be drawn in spatially separated to read out the images held by them. These are then assembled electronically bumpless later.

You can after using the scanner DE 199 42 211 A1 For this purpose, be mounted on a vertically movable table with two movable in the circumferential direction of the cylinder bearing surfaces, which then the film segments in the as predefined Abastgeometrie vorbeifährt at a readout gap of the scanner.

Modifications of the embodiments described above may include:
The cassette specifies a (partially) cylindrical shape of the storage film. The imaging plates can thus be read in their exposure geometry with a normal scanner having a cylindrical film support. If desired, a representation conversion into the panographic representation or a panoramic representation, taking into account the otherwise determined jaw geometry, can be carried out mathematically by point coordinate transformation. The corresponding transformation data can z. B. can be determined experimentally on a phantom head.

An X-ray source with a slender body section that can be inserted into the mouth 20 can also be used for normal intraoral images. It will then be on the housing section 20 a tube placed, from which the X-ray exits laterally collimated. Due to the small diameter of the housing section 20 It is possible to place the X-ray source closer to the jaw up to 7 times than a conventional X-ray source for intraoral imaging. As described above, unnecessary parts of the X-ray light can be masked out by an absorbent cap with a correspondingly designed window.

Instead of a light-tight protective cover 60 For the cassette one can for each memory foil vorzehen a light-tight protective cover. This can also be on the edge of the opening 52 comprise welded foil layers. For many applications, however, is the penetration of a smaller amount of daylight at the edge of the opening 52 also tolerable. A so wrapped memory film is then just as used in the support member, as described above for a naked storage film.

Overall, the examination device described above makes it possible to produce X-ray images of good quality with low radiation exposure of the patient from extended areas of the jaw, and in a cost-effective manner, since the examination device, unlike a panoramic device, does not require a complex and precise guide mechanism. The examination device also requires no structural measures on the room in which it is used.

In 11 is an examination device for making panographic images of the pines of a patient with a total of 200 designated. The examination device consists of a total of 202 designated recording part and a total with 204 designated readout part.

The recording part 202 has substantially the same structure as for the embodiments of the 1 to 8th described. It therefore does not need to be described in detail. For the components, the reference symbols used above are used again.

The support plate 36 which is a storage foil 46 carries, but is now rigid and exactly part-cylindrical. It surrounds the face of a patient 206 under all-sided distance such that the support plate 36 can be moved freely over the patient's head.

For this, the support plate has 36 four eyes, of which in 11 two at 208 and 210 are shown. These are in the eyes 208 and 210 Threaded sleeves used with a threaded spindle 216 work together. The latter is powered by an (electric) engine 146 with resolver 148 powered by a base plate 220 worn the examination device. The two in front of the drawing plane of 11 bearing eyes to be considered are provided with slide bushings and run on a front of the plane to thinking guide rod, which is arranged similar to the threaded spindle 216 but has no thread.

After removing the X-ray source 12 from the hub 34 can then by energizing the engine 146 the support plate 36 be moved in the vertical direction.

The readout part 204 is similar in structure as in 5 shown. Because the readout part 204 according to 11 only for reading a storage foil 46 is determined, which extends over an angle of about 180 °, also needs the circumferential extent of the housing 138 only 180 °. The axis is corresponding 134 on which the deflecting prism 136 (simplified as deflecting mirror shown) rotates, moved to the edge of the housing.

In the peripheral wall of the housing 138 there is a narrow readout slot 222 on the inside with chamfers 224 . 266 is provided.

The entire interior of the case 138 is with a layer 228 which detects which laser light absorbs and fluorescence light, which is due to the laser light in the storage film 46 is triggered, reflected. In this way, the fluorescent light passes directly or via one or more reflections in the photomultiplier 156 ,

For reading the storage foil 46 only needs by excitation of the electric motor 146 the support plate 136 quickly against the reading gap 222 be moved, whereupon the further upward movement the support plate 36 slower, as is desired in view of the desired scan speed.

Moving the storage foil 46 across the reading gap 222 takes place under small play without contact, so that on the memory film 46 even after a long period of use no sanding marks arise.

On the bottom of the case 138 can a circular arc extinguishing lamp 230 be attached, which is the storage film 46 freed of residual images when the storage film together with the support plate 36 in 11 is moved down to take a new picture.

Alternatively, one can also remove the erased storage film (with or without support plate) and replace it with a storage film with other properties (eg size, sensitivity, resolution) (again with or without support plate).

On the way down, the storage foil can then through a patch cap 232 protected against daylight, which when driving back up in the readout part 204 automatically stripped, as in 11 indicated by dashed lines.

12 shows schematically how to convert a Panographiebildes, which with the examination device according to 11 was obtained, can take in a panoramic picture.

A pixel B of the panography image (in the receiving surface A, in the embodiment considered partially cylindrically curved storage film) is connected by a line L with a point R, which is the X-ray source 12 having a substantially spherical characteristic.

Now we look for the intersection of this line with a simply curved surface F, which is adapted to the course of the jaw in the cross-sectional contour. Using a representation of this area (whether in tabular or closed form) and the line L between the pixel B and the location of the X-ray source R can then obtain that point P, which would have been obtained in a panoramic image (in this case would be to be imaged structure having been exposed to a substantially horizontal X-ray beam).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19942211 A1 [0154]

Claims (52)

Cassette for an exposable Marterialstück ( 46 . 48 . 50 ), with an at least partially permeable for X-ray light and visible light impermeable protective cover ( 60 ) and with a supporting part ( 36 ) for the piece of material ( 46 . 48 . 50 ), characterized in that the supporting part ( 36 ) is curved. Cassette according to claim 2, characterized in that the supporting part ( 36 ) is curved in an unloaded state symmetrically to a median plane. Cassette according to claim 1 or 2, characterized in that the supporting part ( 36 ) a base section ( 42 ) and two adjoining these leg sections ( 44 ), wherein the base section ( 42 ) and the leg sections ( 44 ) have different curvature. Cassette according to one of claims 1 to 3, characterized in that at least one of the sections ( 42 . 44 ) of the supporting part ( 36 ) is plastically deformable. Cassette according to claim 4, characterized in that at least one deformable section ( 42 . 44 ) of the supporting part ( 36 ) is repeatedly deformable. Cassette according to one of claims 1 to 5, characterized in that the supporting part ( 36 ) has at least one portion which is elastically deformable or flexible and by a locking device ( 100 to 118 ) is fixable in the deformed shape. Cassette according to Claim 6, characterized in that the locking device has at least one length-adjustable strut ( 100 . 102 ), which on a support part ( 110 ) of the supporting part ( 36 ) and at a given point ( 92 . 94 ) of the supporting part ( 36 ) attacks. Cassette according to claim 7, characterized in that the strut ( 100 . 102 ) via a rotatable clamping head ( 116 ) or a clampable cutting edge bearing ( 104 ) on the support part ( 110 ) is lockable. Cassette according to claim 7 or 8, characterized in that the strut ( 100 . 102 ) a scale ( 122 ), which bears with one of the support part ( 110 ) brand worked together. Cassette according to one of claims 6 to 9, characterized in that the supporting part ( 36 ) has at least two successive sections whose flexibility is different. Cassette according to claim 10, characterized in that the supporting part ( 36 ) has at least one region in which the flexibility continuously changes. Cassette according to claim 11, characterized in that the continuous change of the bendability via an attached stiffening rib ( 90 ) is obtained, whose cross-section and / or area moment of inertia changes in the longitudinal direction of the stiffening rib. Cassette according to one of claims 1 to 9, characterized in that the supporting part ( 36 ) a piece of material ( 46 . 48 . 50 ) covering supporting wall ( 36 ) and at least one with an edge of the piece of material ( 46 . 48 . 50 ) cooperating retaining rail ( 38 . 40 ), preferably two with opposite edges of the piece of material ( 46 . 48 . 50 ) cooperating retaining rails ( 38 . 40 ) Has. Cassette according to claim 13, characterized in that the retaining rails ( 38 . 40 ) the associated edges of the piece of material ( 46 . 48 . 50 ). Cassette according to claim 13 or 14, characterized in that the retaining rails ( 38 . 40 ) with bending recesses ( 54 ) are provided. Cassette according to one of claims 13 to 15, characterized in that the retaining rails ( 38 . 40 ) with successive spaced retaining lugs ( 58 ) are formed. Cassette according to one of claims 13 to 16, characterized in that the retaining rails ( 38 . 40 ) are made of elastically deformable material. Cassette according to one of claims 13 to 17, characterized in that the retaining rails ( 38 . 40 ) at least one pivotable retaining lug ( 58 ), which resiliently into an associated edge of the piece of material ( 46 . 48 . 50 ) overarching position are biased. Cassette according to one of claims 1 to 18, characterized in that the supporting part ( 36 ) is made of a plastic material. Cassette according to one of claims 1 to 19, characterized in that the supporting part ( 36 ) a preferably centrally arranged visible light impermeable hub part ( 34 ) having. Cassette according to claim 20, characterized in that the hub part ( 34 ) light-tight with a front wall ( 64 ) and a back wall ( 62 ) of the protective cover ( 60 ) connected is. Cassette according to claim 21, characterized in that the front wall ( 64 ) and the back wall ( 62 ) are formed by prigmented and / or vapor-deposited and / or coated film sections. Cassette according to claim 21 or 22, characterized in that the front wall ( 64 ) and the back wall ( 62 ) are welded together. Cassette according to one of claims 1 to 23, characterized by a one-sided closed cylindrical hygiene part ( 86 ), which is tight with the protective cover ( 60 ) connected is. Cassette according to one of claims 1 to 24, characterized in that the protective cover ( 60 ) a machine readable identification ( 174 ) wearing. Cassette according to one of claims 1 to 25, characterized in that they are arranged one behind the other in the beam direction holding means for pieces of material ( 46 . 48 . 50 ), which preferably hold the pieces of material held by them ( 46 . 48 . 50 ) give concentric shape. Cassette according to claim 1 or 2, characterized in that the supporting part ( 36 ) is at least in a region of the same part-cylindrical. A storage film for use with a cassette according to any one of claims 20 to 27, characterized in that it has a receiving opening ( 52 ) for the hub part ( 34 ) having. A storage film according to claim 28, characterized in that the receiving opening ( 52 ) than to an edge of the storage film ( 46 . 48 . 50 ) open slot is formed. A storage film according to claim 28, characterized in that it is divided into two segments ( 46A . 46B ), which at one through the center of the receiving opening ( 52 ) run line, this line is preferably perpendicular to a loading direction of the cassette ( 14 ) stands. A storage film according to claim 30, characterized in that the two segments ( 46A . 46B ) each one half of the receiving opening ( 52 ) limiting slot ( 52 ) and at least partially overlap. Device for reading a storage foil ( 46 . 48 . 50 ) exposed in a cassette according to one of claims 1 to 25, characterized by a scanning unit ( 126 to 160 ), by a data processing device ( 162 ) and by at least one unit ( 170 ) for detecting the geometry of the cassette ( 14 ) or the storage foil ( 46 . 48 . 50 ). Apparatus according to claim 32, characterized in that the geometry recognition unit ( 170 ) includes a camera. Apparatus according to claim 32 or 33, characterized in that the geometry recognition unit is a brand reader ( 172 ). Device according to one of claims 32 to 34, characterized in that the scanning unit ( 126 to 160 ) comprises a plurality of scan heads having different readout surfaces (W1, W2, W3) which - preferably smooth - connect to each other and that the scan heads are controlled so that the storage film ( 46 . 48 . 50 ) are read along line pieces, which together are each a coherent, preferably over the entire dimension of the storage film ( 46 . 48 . 50 ) forming a continuous scan line. Apparatus according to claim 35, characterized in that the scanning unit comprises three scan heads, one of which is arranged above a center plane of the scanning unit and two symmetrically to this center plane. Device according to claim 35 or 36, characterized in that the scanning heads rotate around ( 128-1 . 128-2 . 128-3 ) and at different distances from the read-out surface (W1, W2, W3) are arranged and the angular velocity of the readout beams ( 128-1 . 128-2 . 128-3 ) is chosen inversely proportional to the distance of its axis of rotation from the readout surface. Device according to one of claims 35 to 37, characterized in that the scanning units light sources ( 126-1 . 126-2 . 126-3 ) for readout beams ( 128-1 . 128-2 . 128-3 ), which in dependence on the angular position of the respective readout beam ( 128-1 . 128-2 . 128-3 ) to be controlled. Apparatus according to claim 38, characterized in that the control of the switching times of the read-out light sources ( 126-1 . 126-2 . 126-3 ) by electronic locks ( 168-1 . 168-2 . 168-3 ), which depends on the angular position of a beam deflecting element ( 136-1 . 136-2 . 136-3 ) to be controlled. Apparatus according to claim 35, characterized by at least one scan head ( 126 to 160 ), which between a first working position in which it has a first distance from a first read surface (W1), and at least one second working position in which it is a second distance from at least one further read-out surface (W2, W3) is adjustable, wherein the scan head ( 126 to 160 ) reads out the storage film in the different working positions of different areas and the sub-images obtained in this case are assembled electronically into an overall image. Apparatus according to claim 40, characterized in that the scan head ( 126 to 160 ) is movable in three working positions, of which a first is located in a median plane of the device and two more are symmetrical to this center plane. Device according to one of Claims 32 to 41, characterized by a bite-on device ( 82 . 84 ), which is provided with at least one mark, preferably with a plurality of spaced markers in the beam direction. Device according to one of claims 32 to 42, characterized in that the cassette ( 14 ) is provided with holding means XX for an intraoral light detector YY. Examination apparatus for generating X-ray images with a cassette according to one of claims 1 to 27, with a storage film and with an X-ray source, characterized in that the X-ray source ( 12 ) a tubular housing portion ( 20 ) has a small diameter, in which an Antikathodenteil ( 28 ) is housed so that the emission of the X-rays takes place predominantly in the backward direction and the lateral direction, wherein preferably a diaphragm cap ( 192 ), which, depending on its geometry, absorbs parts of the X-ray light emitted into the rear half-space. Examination device according to claim 44, characterized in that the cassette ( 12 ) the piece of material ( 46 . 48 . 50 ) with a curvature corresponding to the curvature of a positioning surface of a scanning unit ( 204 ) corresponds. Apparatus according to claim 45, characterized in that the cassette in the immediate vicinity of the scanning unit is adjustable, so that the material piece held in it is flush with the positioning of the scanning unit. Apparatus according to claim 45 or 46, characterized by a transport device through which the cassette ( 12 ) is movable between a receiving position and the position adjacent to the scanning unit. Method for recording panographic slice images, characterized by the following method steps: a) arranging a panographic X-ray source in front of the structure to be examined; b) arranging a light detector, in particular a storage film, behind the structure to be examined; c) exposing the structure to be investigated; d) storing the image taken by the light detector; e) repeating steps a) to d) for at least two modified relative positions between the X-ray source ( 12 ) and structure to be examined. Method for recording panographic slice images, characterized by the following method steps: a) arranging a panographic X-ray source in front of the structure to be examined; b) arranging a light detector, in particular a storage film, behind the structure to be examined; c) exposing the structure under investigation, while simultaneously d) the X-ray source and the light detectors are moved coordinated with each other so that a layer of the structure to be examined is sharply imaged for each light detector. Method for producing a panographic image, characterized by the following method steps: a) arranging a panographic X-ray source in front of the structure to be examined; b) selecting a light detector whose resolution substantially coincides with the resolution of the X-ray source used; c) exposure of the structure to be examined. A method according to claim 50, characterized in that light detectors are used which carry machine-readable marks and cooperate with a detector sensor whose output signal is used to control the exposure time. Method according to one of Claims 48 to 51, characterized in that the image recorded by the light detector is converted into a panoramic image by inverse transformation of the panographic imaging geometry.

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