WO2017089331A1

WO2017089331A1 - Method for registering x-ray images

Info

Publication number: WO2017089331A1
Application number: PCT/EP2016/078389
Authority: WO
Inventors: Ulrich Schulze-Ganzlin
Original assignee: Sirona Dental Systems Gmbh
Priority date: 2015-11-23
Filing date: 2016-11-22
Publication date: 2017-06-01
Also published as: DE102015223087A1

Abstract

The invention relates to a method for registering x-ray images (1, 14-19). The x-ray images are captured using at least one x-ray imaging medium (2). The x-ray imaging medium (2) is illuminated by means of an x-ray device (5), and an acoustic signal (21) is generated by a sound generator (20) during the illumination process. The acoustic signal (21) is then recorded using a microphone (22). In the process an acoustic recording is produced, and the acoustic recording of the signal (21) is analyzed with respect to different features by means of a computing unit (12). Specific information on the x-ray images (1, 14-19) is derived using the ascertained features of the acoustic signal (21).

Description

description

Procedure for registering x-rays

Technical area

The invention relates to a method for registering X-ray images, wherein the X-ray images are recorded by means of at least one X-ray recording medium, wherein the X-ray recording medium is exposed by means of an X-ray device and during the exposure an acoustic signal is generated by means of a sound generator. State of the art

Several methods for registering X-ray images are known from the prior art, in which the X-ray images are recorded by means of imaging plates or X-ray films, wherein the imaging plates or X-ray films are manually marked by a user or transported in a specific sorting or sequence in a tray , After exposure, the imaging plates are thus stored in sequence in such a tray. Subsequently, the storage sheets are taken out one at a time for scanning and fed to a storage film scanner. The exposed imaging plates are usually identified manually, for example by a numbering, in order to identify the individual images and to establish an association with the respective patient and not to exchange the imaging plates. The exposed X-ray films are first developed and then also scanned to produce the digital X-ray images.

A disadvantage of this method is that by manually marking the X-ray films or the imaging plates and the manual filing in a tray by Lack of attention of the operating personnel, the X-ray films or the imaging plates can be incorrectly marked or stored in the wrong order in the tray, so that there is confusion regarding the order. As a result, X-ray images can be assigned to the wrong patient and the wrong recording area, so that confusion can lead to misdiagnosis and harm to the patient. If such confusions are detected, they usually can not be traced back, so a repetition of the X-ray is required. In addition to the loss of time of an additional X-ray, the additional radiation exposure is disadvantageous.

WO 2010/109064 A1 discloses a medical X-ray imaging system which is suitable for reading out X-ray storage films. The X-ray storage foils are provided with electronically readable identification markings, the so-called tags, which allow identification and thus exclude the risk of confusion.

A disadvantage of this method is that the individual X-ray storage foils must be provided with such identification markings. In addition, these identification marks must be read using appropriate readers on the X-ray machine and on the imaging plate scanner. This is associated with a considerable technical effort.

The object of the present invention is therefore to provide a method for registering X-ray images, which prevents the risk of confusion and can be realized with the least possible technical effort. Presentation of the invention

The invention relates to a method for registering X-ray images, wherein the X-ray images are recorded by means of at least one X-ray recording medium, wherein the X-ray recording medium is exposed by means of an X-ray device and with the triggering of the exposure, an acoustic signal is generated by means of a sound generator. This acoustic signal is then detected by means of a microphone, wherein the acoustic signal is analyzed by means of a computing unit with respect to different features, wherein on the basis of the determined characteristics of the acoustic signal, certain information on the X-ray images is derived.

This information can then be assigned as registration data of the corresponding radiograph.

The acoustic signal can either be immediately after the

Detection can be analyzed or it can first be created an acoustic recording, which is analyzed at a later date. The X-ray recording medium may be an X-ray film, a storage film or even a digital X-ray image detector.

When using an X-ray film, the X-ray film, packed in a light-tight packaging, exposed and placed in a specific order, for example by means of a tray tray. Subsequently, the X-ray films are removed from the tray and developed and fixed by means of an X-ray film developer. The developed X-ray films can then be scanned by means of a digital scanner so that digital X-ray images are generated. A storage film has been developed to replace X-ray films since it is reusable. The imaging plate is then read pixel by pixel after exposure by means of a reading device, so that digital X-ray images are generated. After reading the storage film, this can be reused.

Instead of an X-ray film or a storage film, an intraoral digital X-ray image detector can also be used. The recorded X-ray image data is then read out and forwarded to a computer for further image processing, storage and visualization. As an X-ray image detector, for example, a CCD detector or a CMOS detector can be used. The sounder for the acoustic signal may be, for example, an intended for X-ray devices sounder or buzzer for warning or indication signals for displaying the X-radiation. This tone generator can thus be used according to the present method for the transmission of information about the generated X-ray images. As a result, no extensive conversion of the hardware is required. The sounder only has to be programmed to output a suitable acoustic signal depending on the settings of the X-ray machine.

The sound generator can also be an additional sound generator which is arranged outside the X-ray apparatus.

The microphone for recording the acoustic signal must be in the vicinity of the sounder in order to record the acoustic signal as possible without disturbing background noise.

The microphone can be connected to a computer, wherein the acoustic recording of the signal is transmitted wirelessly or via a cable to the computer for analysis. The microphone can also be integrated into a conventional be smart phone or microcomputer integrated in a microcomputer system, the analysis of the acoustic signal can be done directly by means of the respective microcomputer. The transmission of the acoustic recording of the signal and / or the detected characteristics of the signal can then be transmitted wirelessly to the computer or a management system for managing and archiving X-ray images. Based on the determined characteristics of the acoustic signal, information about the X-ray images, such as exposure time and tube voltage, are then derived.

In conventional X-ray machines, the duration of the emitted warning tone during irradiation usually correlates with the duration of the X-ray exposure. In addition, information about the X-ray image is thus modeled in the acoustic signal by controlling the tone generator.

An advantage of this method is that a conventional X-ray machine can be converted in a simple manner, wherein the existing sounder for a prescribed warning sound is controlled so that the acoustic signal can be evaluated by means of the existing computer.

Another advantage of this method is that the present method provides manual guidance of a

X-ray control book replaces, wherein information on X-ray, such as the patient, the dose and the exposure time, must be entered in writing by the doctor.

Advantageously, the X-ray recording medium can be an X-ray film, a storage film or a digital X-ray image detector. Thus, the present method is applicable to X-ray devices for X-ray films, imaging plates and digital X-ray image detectors.

Advantageously, the sound generator can be arranged on the X-ray apparatus, be a part of the X-ray apparatus and / or be controlled by the X-ray apparatus.

As a result, the sounder already present as standard on the X-ray apparatus is used to generate warning signals during the irradiation for carrying out the present method. The X-ray machine may also have a plurality of sounders, which are controlled accordingly. The sound generator can thus be arranged within a housing of the x-ray device.

Advantageously, the microphone may be positioned within the X-ray apparatus, the sounder or the X-ray apparatus, wherein the microphone is connected to a computer or integrated into a smartphone or a microcomputer system.

As a result, the microphone is positioned in the vicinity of the sound generator in such a way that interfering background noises are minimized as much as possible.

The microphone must be arranged spatially to the sound generator so that a reception of the acoustic signal is ensured.

Advantageously, the arithmetic unit for analyzing the acoustic signal and for deriving the information from X-ray images may be a computer, a smartphone, a tablet computer or a microcomputer.

As a result, the arithmetic unit for carrying out the present method can already be used by most

X-ray machines existing computer for viewing the di- digital radiographs or a conventional smartphone.

In the analysis of the acoustic signal, a database may also be used for various known X-ray devices, which contains the already programmed programmed warning signals of these X-ray devices. As a result, based on the existing warning signal, the type and manufacturer of the respective X-ray device can be detected. This warning signal is then modified according to the present method to encode the X-ray information.

The present method can also use a self-learning system. In this case, the particular X-ray device is assigned to a specific standard warning tone so that it can be recognized later.

Advantageously, the characteristics of the acoustic signal may include a start time, an end time, a pulse duration of a single pulse, a duration of the entire signal, a frequency of the acoustic signal, a

Amplitude of the acoustic signal, a number of pulses and / or a tone sequence.

The mentioned features are thus determined in the analysis of the acoustic signal. The start time, the end time or the pulse duration can be determined, for example, by measuring the exceeding or falling below a specified threshold of the amplitude of the acoustic signal. The frequency of the acoustic signal can be determined, for example, by means of a digital frequency counter or by means of the computer. The individual pulses may differ in frequency, in the frequency response, in the temporal distance from each other and / or in the signal amplitude.

The acoustic signal can therefore also be analyzed with regard to a frequency curve, a time interval between the pulses and / or an amplitude curve. The time-dependent frequency response may include, for example, a time-varying frequency or a plurality of overlapping frequencies. The time-dependent amplitude curve of the signal can also contain coded information.

Advantageously, the information derived from the characteristics of the acoustic signal to the X-ray recordings, an exposure time, a recording time, a tube voltage, a tube current, the use of a

Radiation field limitation, a tube extension, the use of an additional filter, a clear X-ray device identification and / or a status message of the X-ray device. The exposure time is the time in which the X-radiation acts on the X-ray film or on the X-ray image detector.

The recording time is, for example, the time at which the X-ray recording begins or ends. The recording time may also have a different temporal relationship to the time of the X-ray. It is essential that the order of the X-ray recordings can be determined based on the recording time.

The tube voltage is the voltage that accelerates the electrons in the X-ray tube before they hit the anode. The tube current is due to the flow of electrons defined between the hot cathode and the anode. A higher tube current determines a higher intensity of the X-radiation. At constant tube voltage and increasing tube current, the intensity increases linearly. The tube voltage determines the kinetic energy of the electrons accelerated from the cathode to the anode and thus the maximum energy of the X-radiation. The tube voltage affects the composition of the spectrum of the generated X-radiation. For example, a radiation field boundary may be embodied as a tube that is placed on the intraoral X-ray emitter to confine the X-radiation.

With a tube extension, the distance between

Radiation focus and detector can be increased. An additional filter can also be placed on the intraoral X-ray source to modify the X-radiation.

The information about the X-ray recordings can therefore be used to sort the X-ray images in the chronological order with respect to the recording times.

The user, like a doctor, can be guided by the computer when performing the individual x-ray images, whereby the computer indicates which patient's regions of acquisition are to be irradiated in which order and from which direction. When carrying out such a series of photographs, guided by the computer, it is then possible to automatically assign the corresponding recording region to the chronological order of the x-ray images of each x-ray image produced.

Thus, by transmitting the recording time point a clear relationship between the receiving region and the generated X-ray produced.

Advantageously, a pulse duration of a pulse of the acoustic signal may correspond to within a tolerance range of an exposure time, wherein the tolerance range Zvi ^¬ rule -20% and + 20% of the pulse duration of the pulse is.

As a result, the exposure time of the respective X-ray exposure is determined.

Advantageously, a recording time of the respective X-ray recording can be derived on the basis of a point in time of the acoustic signal.

The determination of the recording time of the X-ray image allows the creation of a chronological order, which allows the assignment of the X-ray images. Advantageously, a frequency of the acoustic signal between 1.8 and 2.3 kHz may correspond to a tube voltage between 55 and 65 kV, wherein a frequency of the acoustic signal between 2.3 and 2.8 kHz may correspond to a tube voltage between 65 and 75 kV. Knowing the tube voltage, the exposure time, the tube current and thus a derived dose, the X-ray image can be better evaluated because, for example, the X-ray spectrum varies depending on the tube voltage. Advantageously, the number of pulses of 1 may correspond to a tube current of 6 mA and the number of pulses of 2 to a tube current of 7 mA.

In the knowledge of the tube current, the respective X-ray image can be better evaluated in the context of image processing be because the intensity of the X-ray radiation or the image signal intensity increases with increasing tube current.

Advantageously, to improve the analysis of the acoustic signal, an amplitude filter, a frequency band filter and / or an analysis unit can be used, with disturbing background noises being filtered out and only a predefined frequency range of the acoustic signal being transmitted.

By using an amplitude filter, therefore, the acoustic signal is analyzed only above a predefined minimum amplitude. As a result, disturbing background noise can be filtered out.

By using the frequency band filter, only the predefined frequency range of the acoustic signal is used for the analysis, so that background noises are filtered out. The frequency band filter may be an electronic component or may be provided virtually by means of signal processing software.

The analysis unit can be based on a Fourier transformation method. The Fourier transform method separates continuous, aperiodic signals into a continuous spectrum. The function that describes this spectrum is called the spectral function.

As a result, a digital signal is broken down into its frequency components, which can then be analyzed.

Advantageously, in order to analyze the pulse duration and the number of pulses, the duration between an exceeding and an undershooting of at least one threshold of the amplitude of the acoustic signal can be measured. As a result, the pulse duration and the number of pulses are determined in order to obtain the information about the respective X-ray image.

Advantageously, the information on the X-ray recordings can be decoded based on the determined characteristics of the acoustic signal, this information is forwarded to an X-ray archive system, this information can be registered to the corresponding X-ray and stored in an X-ray database.

As a result, the information determined for the respective X-ray image is thus registered and stored in the X-ray image database.

Advantageously, self-learning of the system can be used in deriving the information on the basis of the characteristics of the acoustic signal.

The self-learning system can thus learn to derive the information based on the characteristics of the acoustic signal. The user can enter information such as an exposure time, a tube voltage, a tube current or a unique X-ray device identification manually after several X-ray recordings, so that the system itself learns to derive this information based on the characteristics of the acoustic signal. One possible embodiment of the present method could include the following steps: an X-ray job comprising a patient name and an indication is registered by a user, such as a physician, on an X-ray imaging filing system; the X-ray parameters, such as the tube voltage and the tube current, are determined by the user on the X-ray machine; the x-ray receiving medium, such as an intraoral sensor, is positioned in the patient's mouth; the intraoral X-ray is positioned relative to the patient; the X-ray is triggered by means of an operating element by the user; at the intraoral X-ray machine, the acoustic signal is generated; the acoustic signal is recorded by means of a microphone; the acoustic signal is processed and evaluated for improvement by means of a signal analysis unit, which may comprise a frequency filter and / or an amplitude filter, whereby the determined characteristics of the acoustic signal are determined; Information about the respective X-ray image is derived on the basis of the determined characteristics of the acoustic signal; the determined information on the X-ray image is forwarded to an X-ray recording archiving system; the information obtained is registered to the respective X-ray photograph; the X-ray images with the corresponding information are stored in an X-ray database. Brief description of the drawings

The invention will be explained with reference to the drawings. It shows that

1 is a sketch to illustrate the present method when using an X-ray device for memory films, the

Fig. 2 is a sketch to illustrate the present method when using an X-ray device for intraoral sensors, the

Fig. 3 is a diagram of the acoustic signal as a function of time, the Fig. 4 is a diagram of a frequency of the acoustic

Signals as a function of time.

embodiments

1 shows a schematic sketch to illustrate the present method for registering X-ray recordings 1. The X-ray recordings 1 are recorded by means of an X-ray recording medium 2. In the illustrated case, the X-ray recording medium 2 is an X-ray film or a storage film, which is deposited after exposure in a tray 3, as shown by the arrow 4. The X-ray device 5 comprises an X-ray source 6. The X-ray film 2 or the storage film is positioned relative to an object 8, namely the male portion of the teeth or the jaw, respectively. Within the scope of a series of photographs, therefore, a plurality of x-ray images of different regions of an upper jaw and / or a lower jaw are recorded. After each exposure, the storage film 2 or the X-ray film is deposited in the tray 3 in a specific sequence. Subsequently, the storage films 2 are read out by means of a storage film scanner 11, as indicated by the arrow 12. The generated two-dimensional digital X-ray images are then transmitted from the imaging plate scanner 11 to a computer, as shown by the arrow 13. If the radiographic media are 2 x-ray films, they may instead be developed, fixed and scanned by a digital scanner so that digital x-ray images are also generated which are transmitted to a computer. In the present series of photographs, a first radiograph 14 of a first recording region of the left molar teeth of the upper jaw, a second radiograph 15 of the incisors of the Upper jaw, a third radiograph 16 of the right molar teeth of the upper jaw, a fourth X-ray imme 17 of the left molar teeth of the lower jaw, a fifth radiograph 18 of the incisors of the lower jaw and a sixth radiograph 19 of the right molars of the lower jaw taken. The user can also perform a recording session under the guidance of the computer, with the areas to be recorded displayed before recording. The user, such as a physician, can then set the appropriate recording regions on the X-ray machine 5. The computer registers an X-ray image via the acoustic signal and, if necessary, guides the user via a user guide to the next X-ray exposure to be carried out. The x-ray device 5 comprises a sound generator 20, such as a loudspeaker, which generates an acoustic signal 21 during the exposure of an x-ray image. This acoustic signal 21 is then recorded by means of a microphone 22. The acoustic recording is then forwarded to the computer 24, as shown by the arrow 23. The microphone 22 should be located in the vicinity of the sounder 20 to record a clear acoustic signal without background noise. The acoustic pick-up of the signal 21 is then analyzed by the computer 24 for different characteristics such as the start time, a pulse duration, an amplitude of the acoustic signal or the frequency of the acoustic signal. Subsequently, on the basis of the determined characteristics of the acoustic signal 21, specific information on the X-ray recordings, such as the exposure time, the recording time, the tube voltage or the tube current, is determined. The computer 24 is connected to controls such as a mouse 25 and a keyboard 26. The computer 24 has a memory 27 which is used for storing an X-ray database; is used. The computer 24, the controls 25 and 26 and a display unit 28, such as a monitor, thus form an X-ray retrieval system 29. An X-ray archiving system 29 can also extend over a plurality of computers and a data network.

FIG. 2 shows a sketch to illustrate the present method for registering X-ray images 1, wherein an X-ray device 5 is used for dental intraoral X-ray diagnostics. In this case, an intra-oral, digital sensor 30, which is arranged between the teeth 31 and the tongue 32 of the patient, is used. Instead of a digital sensor and a storage film for intraoral recordings can be used. The intraoral sensor 30 is an X-ray receiving medium according to the present method. In the present embodiment of an intraoral radiograph, the intraoral sensor 30 is all used a digital x-ray image sensor. The intraoral sensor 30 is irradiated by means of a radiator 33 for dental, intraoral X-ray diagnostics, as shown by the dashed lines 34. The X-ray device 5 thus comprises the X-ray emitter 33 and the sound generator 20. Subsequently, the intraoral sensor 30 is read out by means of an intraoral X-ray recording system 35 and thereby an X-ray image 1 is detected, which is transmitted to the computer 24, as shown by the arrow 36. The intraoral X-ray recording system 35 can therefore be a reading device in order to read out the image data of the intraoral sensor. The image data of an intraoral sensor can also be forwarded directly to the computer 24. After an initial X-ray 37 of the left molars of the maxilla and mandible becomes the intraoral sensor 30 in a second recording region 38 in the area of

Incisors of the upper jaw and the lower jaw positioned and exposed by means of the radiator 33. After the intraoral sensor 30 has been read again by means of the intraoral x-ray recording system 35, a second x-ray image 39 is generated. The two X-ray images 37 and 39 are displayed by means of a display device 40, such as a monitor, which is connected to the computer 24. During the exposure of the X-ray exposure 1, the acoustic signal 21, which is recorded by means of the microphone 22, is generated by means of the sounder 20, the acoustic recording being transmitted to the computer 24.

The image data of the X-ray image are thus forwarded to the computer 24 by the X-ray recording medium, such as the intraoral sensor 30 or a storage foil, depending on the type of X-ray image position.

Subsequently, the acoustic signal for this X-ray image is analyzed by means of the computer 24 and the information obtained, such as recording time, exposure time and tube voltage, is assigned to this X-ray image.

However, the intraoral sensor 30 may also be wired or wirelessly connected to the computer 24 during exposure, so that the captured X-ray image data is transmitted directly to a computer. In this case, the recording time of the respective transmitted X-ray image is already known, so that only the remaining information, such as the exposure time and the tube voltage, are transmitted to the computer by means of the coded acoustic signal. The computer 24 is connected to controls such as a mouse 25 and a keyboard 26. The acquired data or information and its assignment to an X-ray image can be managed in the X-ray acquisition archive system 29 to which the X-ray acquisition database 27 is assigned. FIG. 3 shows a diagram of an amplitude 41 of the acoustic signal 21 as a function of the time 42. In the analysis of the acoustic signal 21, a first pulse 43 having a first pulse duration 44 and a second pulse 45 having a second pulse duration 46 are determined. At the beginning of the first pulse 43, a recording time 47 is determined. In the evaluation or decoding of the acoustic signal 21, the present information can then be derived for the corresponding X-ray image 1 from FIGS. 1 and 2. The pulse duration 44 of the longest pulse, ie the first pulse 43, corresponds to an exposure time of the respective X-ray exposure 1. The recording time 47 can correspond to the duration of the acoustic signal 21 at any time between an initial time 48 and an end time 49. The number of pulses, in the present case 2 pulses, corresponds, for example, to a tube current of 7 mA.

4 shows a diagram of a frequency 50 of the acoustic signal 21 as a function of the time 51, wherein a first frequency 52 of a first acoustic signal 53, for example, a first radiograph 2 kHz and a second frequency 54 of a second acoustic signal 55, for example, a second X-ray exposure is 2.5 kHz. In the evaluation or decoding, the first frequency 52 of 2 kHz corresponds, for example, to a tube voltage of 60 kV, the second frequency 54 of 2.5 kHz corresponding, for example, to a tube voltage of 70 kV. In this way, so from the features of the acoustic signal 21 obtained certain information about the respective X-ray images from Figures 1 and 2.

reference numeral

1 x-ray

2 X-ray recording medium, e.g. Storage film or film

3 shelves

4 arrow

5 x-ray machine

6 X-ray source

8 object

11 imaging plate scanner

12 arrow

13 arrow

14 First X-ray

15 Second X-ray

16 Third X-ray

17 Fourth X-ray

18 Fifth X-ray

19 Sixth X-ray

20 sounders

21 Acoustic signal

22 microphone

23 arrow

24 computers

25 Mouse control

26 Keyboard control

27 X-ray database 29 X-ray retrieval system

30 x-ray recording medium, such as digital sensor, storage foil or film

31 teeth

32 tongue

33 spotlights

34 X-ray cone

35 IO X-ray imaging system, e.g. in conjunction with digital x-ray image detector, storage foil or film

36 arrow

37 First X-ray

38 Second Recording Region

39 Second X-ray

40 display device

41 signal amplitude axis

42 timeline

43 First Impulse

44 First pulse duration

45 Second impulse

46 Second pulse duration

47 recording time

48 start time

49 End time

50 frequency axis

51 Timeline

52 First frequency Frequency response of the first acoustic signal Second frequency

Frequency response of the second acoustic signal

Claims

claims

Method for registering X-ray images (1, 14-19, 37, 39), wherein the X-ray images are recorded by means of at least one X-ray recording medium (2, 30), wherein the X-ray recording medium (2, 30) is exposed by means of an X-ray device (5) and triggering the exposure an audible signal

(21) is generated by means of a sounder (20),

characterized in that this acoustic signal

(21) is detected by means of a microphone (22), wherein the acoustic signal (21) by means of a computing unit

(24) is analyzed with respect to different features, wherein on the basis of the determined characteristics of the acoustic signal (21) certain information on the X-ray recordings (1, 14-19, 37, 39) are derived.

A method according to claim 1, characterized in that the X-ray recording medium (2, 30) is an X-ray film, a storage film or a digital X-ray image detector.

A method according to claim 1 or 2, characterized in that the sounder (20) on the X-ray device (5) is arranged, that the sounder is a part of the X-ray device and / or by the X-ray device (5) is driven.

Method according to one of Claims 1 to 3, characterized in that the microphone (22) is positioned inside the x-ray device, on the x-ray device (5) or on the sounder (29), the microphone (22) being connected to a computer (24) or integrated in a smartphone, a tablet computer or a microcomputer system.

5. The method according to any one of claims 1 to 4, characterized in that the arithmetic unit (24) for analyzing the acoustic signal (21) and for deriving the information from X-ray recordings (1, 14-19, 37, 39), a computer (12 ), a smartphone, a tablet computer or a microcomputer.

6. The method according to any one of claims 1 to 5, characterized in that the features of the acoustic signal (21) a Anfgsgspunkt (48), an end time (49), a pulse duration (44) of a single pulse

(43), a duration of the entire signal, a frequency (52, 54) of the acoustic signal (21), an amplitude of the acoustic signal, a number of pulses, the time interval between two consecutive pulses and / or a tone sequence.

7. The method according to any one of claims 1 to 6, characterized in that the information derived from the characteristics of the acoustic signal (21) to the X-ray recordings (1, 14-19, 37, 39) an exposure time, a recording time (47 ), a tube voltage, a tube current, the use of a radiation field limitation, a tube extension, the use of an additional filter, a clear x-ray device identification and / or a status message of the

X-ray device are.

8. Method according to claim 6, characterized in that a pulse duration (44) of a pulse (43) of the acoustic signal (21) corresponds within a tolerance range of an exposure time, the tolerance range being between -20% and + 20% of the pulse duration

(44) of the pulse (43).

9. The method according to claim 6, characterized in that a recording time (47) of the respective X-ray images (1, 14-19, 37, 39) based on an arbitrary time point (48, 49) of the entire acoustic signal

5 nals (21) is derived.

10. The method according to claim 6, characterized

a frequency (52) of the acoustic signal (21) between 1.8 and 2.3 kHz corresponds to a tube voltage between 55 and 65 kV, wherein a frequency (54) of the 0 acoustic signal (21) lies between 2.3 and 2, 8 kHz corresponds to a tube voltage between 65 and 75 kV.

11. The method according to claim 6, characterized

that the number of pulses of 1 corresponds to a tube current of 6 πιΑ and the number of pulses (43, 45) of 2 5 nem tube current of 7 mA.

12. The method according to any one of claims 1 to 11, characterized in that to improve the analysis of the acoustic signal (21) an amplitude filter, a frequency band filter and / or an analysis unit is used ver, wherein interfering noise is filtered out and only a predefined Frequency range of the acoustic signal (21) is passed.

13. The method according to claim 12, characterized in that for the analysis of the pulse duration (44), the temporal

25 distance between two consecutive pulses, and the

Number of pulses, the duration between exceeding and falling below at least one threshold of the amplitude of the acoustic signal (21) is measured.

14. The method according to any one of claims 1 to 13, characterized in that the information about the X-ray These information is transmitted to an X-ray archive system (29), wherein this information is registered to the corresponding X-ray image and stored in an X-ray database (27).

15. The method according to any one of claims 1 to 14, characterized in that when deriving the information based on the characteristics of the acoustic signal (21), a self-learning system is used.