DE202007008008U1 - Device for tomography for tissue examinations of body parts - Google Patents

Abstract

contraption (1) for tomography for tissue examination of body parts (5), in particular in the mouth area, comprising a first arrangement of mechanical agents (4.1, 15), with any number of pathogens (4.1, 15) are selectable both as transmitter and as receiver, wherein the coupling of the of the exciters (4.1, 15) emitted mechanical excitations and the decoupling of the pathogens (4.1, 15) received mechanical stimuli via one between the pathogens (4.1, 15) and the body part to be examined (5) arranged deformable Medium (6), characterized in that at least one second arrangement of mechanical exciters (4.2, 16, 17) is provided is, wherein the first arrangement of pathogens (4.1, 15) and the at least second arrangement of exciters (4.2, 16, 17) including a Space for receiving the body part to be examined (5) on means (2, 3, 11, 12, 13) for fixed alignment with respect to body part (5) are arranged, further provided an evaluation unit (7) is in the both ...

Description

Technical area

The The invention relates to a device for tomography for tissue examinations of body parts, especially in the mouth area on the basis of mechanical suggestions. The mechanical stimuli are generated by pathogens that both as a sender as well as a receiver are controllable.

State of the art

From the EP 0 353 209 A1 For example, there are known a method and apparatus for ultrasound scanning using an array of ultrasound transducers having the ability to shape the beam to achieve an angle of incidence nearly perpendicular to the surface to be examined and to vary the focus of the beam , The method and the device are preferably applicable for intraoperative endodontic diagnosis, in particular for determining the position of intradental probes.

From the US 6,162,177 For example, an apparatus and method for ultrasonically examining fine surface lesions of tooth crown surfaces are known. The apparatus includes an ultrasonic surface acoustic wave generator capable of generating ultrasonic surface waves on a tooth surface and an ultrasonic surface receiver receiving the surface acoustic waves.

The US 5,115,813 discloses a method and apparatus for ultrasonography of dense tissues, particularly dental tissue. The method is based on the pulse-echo principle. The ultrasonic signal is superimposed by a low-frequency vibration.

The US Pat. No. 6,638,219 B1 discloses a method for displaying internal 3D structures of tooth formations. For this purpose, a transducer device is provided which radiates an ultrasonic pulse directly onto the tooth formations to be examined, the ultrasound response of the tooth formation being measured. The ultrasound exciters are arranged on a rotating arc in a housing.

From the US 6,589,054 B2 is a method for examining teeth by means of transit time measurements known. For this purpose, an excitation wave is generated, passed through the tooth and received on the opposite side of the tooth.

The known methods have the disadvantage that in each case only one measuring principle is used. This is the measuring accuracy as well as the possibility for measuring shadowed by bad conducting areas rearward areas highly limited.

It is therefore the object of the invention, a device for surveying of teeth to provide an improved resolution even under problematic Measurement conditions allows. Another object of the invention is to provide an easy to handle Specify device for surveying.

Presentation of the invention

The inventive device for tomography is described by the features of the independent claim 1.

A Device for tomography for Tissue examinations of body parts, especially in the mouth area, comprises a first arrangement of mechanical Pathogen, being any number of pathogens both as a transmitter as well as the recipient selectable are, with the coupling of the emitted by the pathogens mechanical Suggestions and the extraction of the received from the pathogens mechanical impulses over one between the pathogen and the body part to be examined arranged deformable medium takes place. It is at least one second arrangement provided by mechanical exciters, wherein the first array of agents and the at least second arrangement of pathogens including a space for receiving the to be examined body part are arranged on means for stationary alignment with respect to the body part. Furthermore, an evaluation unit is provided in which both mechanical Suggestions from the transmission and from the reflection and / or the Scattering be detected and evaluated on the body part to be examined.

A such device allows a high resolution Three-dimensional measurement of tissue, such as teeth. at Teeth exists the problem that some fillings or other dentures are not radiolucent and on an x-ray show a black shadow. Often these are the dentures parts adjacent areas of the tooth especially caries sensitive, so that is a non-destructive three-dimensional Inclusion of such a tooth is particularly desirable.

According to the invention, either transmission and reflection or transmission and scattering or transmission and reflection and scattering are evaluated. This allows for the best possible up solution of the area to be examined, which is located in the space between the at least two arrangements of pathogens.

The Pathogens are by means of a deformable medium to be examined body part arranged, the air gaps in the space between pathogen and body part prevented.

advantageously, the exciters are designed as ultrasonic transducers and the mechanical Suggestions are ultrasonic signals. Ultrasound signals have one comparatively short wavelength, what with a high possible resolution accompanied. About that In addition, ultrasonic transducers are compact and inexpensive to produce. The introduction of a variety of ultrasound exciters in the therefore easily possible.

advantageously, is the body part to be examined a hard tissue, in particular a tooth hard substance.

From It is particularly advantageous if the medium is a gel, a highly viscous liquid or a soft solid is. this makes possible the use of the tomography device on both the upper and on the lower jaw without the risk of leakage of the coupling medium.

Especially It is advantageous if the medium is a gel pad. Such a gel pillow is easier to handle than a loose medium and beyond reusable.

advantageously, gels the medium bubble-free and can be liquid between the pathogen and the to be examined body part be introduced. This facilitates the application of the medium.

Especially It is advantageous if the means for fixed alignment in Their dimensions are designed so that they are insertable into the mouth and if at least one array of pathogens is at least the width of a tooth. This facilitates the use of the tomography device and increased the possible Resolution.

advantageously, are the first order of pathogens and the least second Arrangement of pathogens on the mutually facing sides of a Clamp arranged. A clamp is easy to position and can be pressed against the tooth with a predeterminable pressure.

alternative An arrangement is conceivable in which the first arrangement of pathogens and the second array of pathogens disposed on a U-shaped support are curved in the third spatial direction so that it takes the form of a Kiefer at least partially recreates. The devoted ones Shape reminiscent of a dental impression tray, with the footprints of tooth to be created. The advantage of such a space-fixed arrangement of pathogens is that the positional relationship of the pathogens to each other is known and thereby increased resolution guaranteed can be. The medium is preferably a gelling or malleable, hardenable Dimensions.

advantageously, Another arrangement of pathogens is provided, which is another Side of the first arrangement of pathogens and the second Arrangement of pathogens formed at least partially covers.

to Achieving the highest possible isotropic resolution it is theoretically ideal if the pathogens on a spherical surface around the Tooth are arranged around. Such an arrangement comes this Ideal relatively close.

Brief description of the drawings

Of the Tomograph according to the invention will be explained with reference to the drawings. Show it:

1 a first embodiment of the tomograph in a schematic representation, the

2 an alternative embodiment of the tomograph in a schematic representation, the

3A a schematic three-dimensional representation of another alternative embodiment of the tomograph, the

3B a section from 3A in a different perspective, that

3C a section through a tomograph according to 3A , the

4A -C schematic representations of transmission, reflection and scattering and the

5 the course of an excitation within a tooth.

Embodiment of the invention

1 shows a tomograph according to the invention 1 for intraoral application in a schematic representation. The tomograph 1 includes holding devices 2 . 3 on which pathogens 4.1 . 4.2 arranged in groups. Using the fixtures 2 . 3 become the pathogens 4.1 . 4.2 concerning a tooth 5 fixed in place. The pathogens 4.1 . 4.2 are designed as ultrasonic exciters and Kings Both send and receive mechanical ultrasonic excitations.

ultrasonic driver are particularly well suited for tomography of tooth tissue, as the wavelength the ultrasonic waves is small compared to the recorded Structures.

A between the holding devices 2 . 3 and the tooth 5 cavity is with a gel 6 filled. The gel 6 is used to transmit the from the pathogens 4.1 . 4.2 emitted ultrasound excitations. In the case of excitations in the ultrasonic range, air gaps or transitions in which the speed of sound deviates extremely from each other must be avoided. Reflections take place at such transitions, which would greatly reduce the energy transmitted to the object to be excited. The gel used 6 has similar acoustic properties to water and is very suitable for transmitting mechanical stimuli. Alternatively to the gel, other media may be provided, for example a cushion of deformable material free of air bubbles on the tooth 5 snuggles and also has good acoustic transmission properties.

Another component of the scanner is an evaluation unit 7 that with the tooth 5 lying components of the tomograph is connected so that data from the pathogens 4.1 . 4.2 to the evaluation unit 7 can be transmitted. The evaluation unit 7 In addition, it can control and energize the pathogens 4.1 . 4.2 serve.

The pathogens 4.1 . 4.2 are arranged in two groups, the pathogens 4.1 and 4.2 the tooth 5 between them. The pathogens 4.1 and 4.2 are essentially aligned so that their respective vibration axis 8th essentially in the direction of the tooth 5 has. The resulting assembly has an arc shape.

Another embodiment of the invention is shown in FIG 2 shown. A tomograph 10 has three holding devices 11 . 12 . 13 on. The holding devices 11 . 12 . 13 be of a pair of pliers 14 held. At the three fixtures 11 . 12 . 13 are each arrangements of pathogens 15 . 16 . 17 in the direction of the tooth 5 are aligned.

One between the fixtures 11 . 12 . 13 and the tooth 5 cavity is with a gel 6 filled.

Unlike the in 1 shown arrangement are in the in 2 shown tomographs 10 three sides of the tooth 5 of pathogens 15 . 16 . 17 surround. Thus, it is possible also scattered signals on the occlusal side of the tooth 5 emerge, receive or send from the direction of the occlusal surface. The resolution and the accuracy of the recordings decreases with the third excitation arrangement 17 especially in directions perpendicular to the occlusal plane.

The forceps 14 serves to the holding devices 11 . 12 . 13 stationary on the tooth 5 to position and allows easy handling. By spreading the lower part of the pliers 14 Forces are exerted on the holding devices, represented by arrows, which hold the holding devices 11 . 12 . 13 to the tooth 5 press.

3A shows a further alternative embodiment of a tomograph according to the invention 18 in a schematic, three-dimensional representation. The tomograph 18 includes a holding device 19 , a grip area 20 and a data cable 21 ,

The holding device 19 is designed in the manner of a impression tray. On the inside facing the teeth 19.1 the holding device 19 are sensor groups 22.1 , 22.2 and 22.3 , The sensor group 22.1 is arranged buccally or labially, the sensor group 22.2 is occlusally arranged and the sensor group 22.3 is arranged lingually. The holding device 19 is essentially a torus segment, wherein the sensor groups 22.1 . 22.2 and 22.3 around the teeth to be measured (not shown) form a substantially circular arrangement in the radial direction.

The design of the holding device 19 like a impression tray has significant advantages. On the one hand, the inner wall forms 19.1 a kind of tub, in which the deformable medium can be brought without difficulty to the tooth and in the inter mediate area between teeth and sensors, on the other hand, the positional relationship of the sensor groups 22.1 . 22.2 and 22.3 through the geometry of the holding device 19 fixed and therefore known and third allows the holding device 19 a tomography of a whole jaw half at a time.

The 3B shows a section 3A in a different perspective. The final end of the fixture 19 is shaped in such a way that as close as possible to the jaw is reached at the jaw to be measured.

3C shows a section along the line AA 3A , The sensor groups 22.1 . 22.2 and 22.3 are in the holding device 19 admitted. The sensor groups 22.1 . 22.2 and 22.3 be by means of the cable 21 energized and can receive signals via the cable 21 not to the dar put evaluation unit 7 send. The cable 21 is designed to supply all individual sensor elements and to receive signals from all individual sensor elements. The structural design of the cable 21 or the supply lines is not the subject of the invention, possible structural configurations are well known in the art.

In the 4A -C are the basic acoustic phenomena that are evaluated in the device according to the invention shown.

4a shows the transmission of a signal 27 through the tooth 5 , The signal 27 is through one on the holding device 2 located, not shown pathogen generated and by another exciter, not shown on the holding device 3 in the illustrated direction of the transmitted signal 27 lies, as a signal 20 ' receive. The signal 27 ' carries information about the condition of the tooth in terms of signal amplitude, waveform, transit time, and phase information.

In 4b becomes the reflection of a signal 28 represented, wherein contrary to the representation of the reflected signal 28 ' from the same exciter, the stimulus 28 has been received. Reflection occurs at the interface between two materials with different characteristic impedance. Unless the pathogen is aligned along the normal of the tooth surface, the reflected signal will be reflected at an angle and received by another pathogen of the same group of pathogens.

4c shows the scatter of the excitation 29 attached to interfaces inside the tooth 5 takes place. The scattered signals 29 ' can be scattered in all directions, with multiple scattering, it is also possible that scattered signals again along the direction of vibration of the corresponding exciter run. Scattered signals are different from transmitted or reflected signals in terms of their transit time and signal level, and are therefore well distinguishable from them.

5 shows the propagation of an excitation signal 30 inside the tooth 5 , Multiple scatters are not shown for reasons of clarity. In the tooth 5 there are areas 31 . 32 with compared to normal dentin of different density. The area 31 is a medullary cavity and the area 32 is a carious area.

When hitting the tooth surface 5.1 becomes a part of the excitation signal 30 reflected in wave mechanics and another part of the signal 30 enters the tooth. The propagation of the signal 30 from one point of the tooth surface is in three different directions as partial signals 30.1 . 30.2 and 30.3 exemplified.

The partial signal 30.1 will be at the interface 32.1 of the carious area 32 reflects at an angle and leaves the tooth 5 as a scattered signal in a direction different from the direction of the incoming signal 30 differs.

The partial signal 30.2 propagated by the tooth 5 without experiencing a change of direction.

The partial signal 30.3 meets the interface 31.1 between the medullary cavity 31 and the dentin of the tooth 5 , Part of this partial signal 30.3 is reflected at the interface and occurs as a partial signal 30.3 ' out of the tooth, while another part through the medullary cavity 31 propagated, this leaves behind and as a partial signal 30.3 '' out of the tooth 5 exit.

1

tomograph

2

holder

3

holder

4.1

pathogen

4.2

pathogen

5

tooth

5.1

tooth surface

6

gel

7

evaluation

8th

axis of oscillation

10

tomograph

11

holder

12

holder

13

holder

14

tongs

15

pathogen

16

pathogen

17

pathogen

19

holder

19.1

inside

20

grip area

21

data cable

22.1-22.3

sensor groups

27 '

signal

28

signal

28 '

signal

29

stimulation

30

signal

30.1-30.3

partial signal

31

Area

32

Area

32.1

interface

Claims (9)

Contraption ( 1 ) for tomography for tissue examinations of body parts ( 5 ), especially in the mouth area, comprising a first arrangement of mechanical agents ( 4.1 . 15 ), with any number of pathogens ( 4.1 . 15 ) can be selected both as a transmitter and as a receiver, the coupling of the pathogens ( 4.1 . 15 ) emitted mechanical excitations and the coupling of the exciters ( 4.1 . 15 ) received mechanical stimuli via a between the pathogens ( 4.1 . 15 ) and the body part to be examined ( 5 ) arranged deformable medium ( 6 ), characterized in that at least one second arrangement of mechanical exciters ( 4.2 . 16 . 17 ), the first array of pathogens ( 4.1 . 15 ) and the at least second arrangement of pathogens ( 4.2 . 16 . 17 ) including a space for receiving the body part to be examined ( 5 ) on resources ( 2 . 3 . 11 . 12 . 13 ) for stationary alignment with respect to the body part ( 5 ), wherein furthermore an evaluation unit ( 7 ), in which both mechanical excitations ( 27 . 28 . 29 ) from the transmission ( 27 ' ) and from reflection ( 28 ' ) and / or scattering ( 29 ' ) on the body part to be examined ( 5 ) and evaluated, the first array of pathogens ( 4.1 . 15 ) and the second array of pathogens ( 4.2 . 16 . 17 ) are arranged on a U-shaped support which is curved in the third spatial direction so that it replicates the shape of a jaw, at least in sections. Device according to claim 1, characterized in that that the carrier in a kind of impression tray ge is formed, wherein the medium is preferably a gelling or moldable, hardenable mass is. Device according to one of claims 1 or 2, characterized in that a further arrangement of pathogens ( 17 ), which is another side of the first array of pathogens ( 15 ) and the second array of pathogens ( 16 ) formed at least partially covers. Device according to one of claims 1 to 3, characterized in that the pathogens ( 4.1 . 4.2 . 15 . 16 . 17 ) are designed as ultrasonic transducers and the mechanical excitations ( 27 . 28 . 29 ) Are ultrasonic signals. Device according to one of claims 1 to 4, characterized in that the body part to be examined ( 5 ) is a hard tissue, in particular a tooth hard substance. Device according to one of claims 1 to 5, characterized in that the medium ( 6 ) is a gel, a highly viscous liquid or a soft solid. Device according to one of claims 1 to 5, characterized in that the medium ( 6 ) is a gel pillow. Device according to one of claims 1 to 6, characterized in that the medium ( 6 ) is bubble-free and fluid between the pathogens ( 4.1 . 4.2 . 15 . 16 . 17 ) and the body part to be examined ( 5 ) is introduced. Device according to one of claims 1 to 8, characterized in that the means ( 2 . 3 . 11 . 12 . 13 ) are designed for fixed orientation in their dimensions so that they are insertable into the mouth and that at least one array of pathogens ( 4.1 . 4.2 . 15 . 16 . 17 ) has at least the width of a tooth.