WO2007137848A1

WO2007137848A1 - Device and method for representing the inner structure of a body by means of laser-induced ultrasound diagnosis

Info

Publication number: WO2007137848A1
Application number: PCT/EP2007/004822
Authority: WO
Inventors: Somakanthan Somalingam
Original assignee: Somakanthan Somalingam
Priority date: 2006-05-31
Filing date: 2007-05-31
Publication date: 2007-12-06
Also published as: DE102006025756A1

Abstract

An ultrasound diagnosis device is disclosed, comprising at least one laser source (21, 31) and at least one analyser, the laser source (21, 31) generating ultrasound waves (61) by means of pulsed laser irradiation (26) on the surface of a body (1) and in the analyser, the echo of the ultrasound waves (61) is recorded interferometrically and analysed. According the invention, a laser modulator is provided and the laser modulator is designed to vary the laser pulse duration of the laser irradiation (26), wherein the laser pulse duration may be set to at least two different laser pulse durations in order to alter the frequency of the generated ultrasound waves (61).

Description

DEVICE AND METHOD FOR PRESENTING THE INTERNAL STRUCTURE OF A BASKET BY MEANS OF LASER-INDUCED ULTRASOUND DIAGNOSIS

The invention relates to an ultrasonic diagnostic device according to the preamble of claim 1 and a method for non-invasive, two- and / or three-dimensional representation of the internal structure of a body according to claim 1 1.

Sonography is the application of ultrasound as an imaging procedure

10 for the investigation of organic tissue in medicine and veterinary medicine as well as technical structures. The generation of an ultrasound image in medicine is based on the fact that ultrasound irradiated into the body is reflected to different degrees on different tissues. When transitioning between media of different densities, the speed of sound changes.

15 speed and it comes at interfaces according to the acoustic impedances to reflections. In medical diagnostics ultrasonic waves are used in pulses, that is as wave packets. The time difference between the signal generation and the signal reflected from different types of tissue is measured. From this value for the term is taken into account

The speed of sound in tissue calculates the distance between the sensor on the body and the reflective layer inside the body. With a computer, this distance information is processed into an image. Structures smaller than the wavelength of the ultrasound used can no longer be resolved. For the diagnosis therefore are in the

25 usually applied frequencies from 2 MHz to 8 MHz. It is true that the sound penetrates deeper into the tissue, the lower its frequency.

With the Schnittbildsonographie information about the anatomy of the body organs and the tissue can be obtained. Doppler sonography is used

30 inter alia, the examination of the cardiovascular system. With the help of the established blood flow velocities it allows to make statements about constrictions and occlusions of the vessels. Not only one blood cell is registered in the blood, but many blood cells with different speeds. In the spectral Doppler method, the vessel is only used by

35 cut a sound beam. It is thus measured at a fixed time and thus determines the spectral velocity distribution of the blood. In the color Doppler method is measured at different locations simultaneously and the runtime selected selectively. Thus, a spatial distribution of the blood velocity can be obtained.

The generation of ultrasound and the reception of echo signals is based on the reverse piezoelectric effect in conventional sonography methods. By applying an alternating electrical voltage to a piezoelectric crystal, this deforms and is excited to vibrate, whereby sound waves are emitted. In the case of reception, the sound signals that occur cause a deformation of the crystal. These deformations cause an electrical charge shift in the crystal, which can then be tapped as electrical voltage. As sources and receivers mainly crystals of lead zirconate titanate are used. The transducer of a diagnostic device contains one or more piezoelectric elements, which can be arranged differently.

Conventional methods of ultrasound generation and detection using piezoelectric crystals require a matched sound transmission medium, such as a gel layer, to transmit the ultrasonic wave from the generator or to the detector to or from the body with reduced loss. This requires direct contact with the body. The intended use of electro-mechanical components leads to their wear, which is also disadvantageous.

WO 02/054948 A1 discloses a device for evaluating the tooth structure using laser-based ultrasound, which has a pulse laser for laser-induced ultrasound generation and an optical interferometric detection device for optically detecting the sound wave forms generated inside and on the surface of the tooth structure ,

The invention has for its object to provide an ultrasound diagnostic device and a method of the type mentioned above, the one for the patient in terms of radiation exposure, contrast agent loading and application of gel layer or the like stress-reduced and simultaneously accurate representation of internal Organs, vessels and tissue structure allow. In addition to be guaranteed according to the task automation of the examination of a patient. The above objects are achieved by an ultrasonic diagnostic device having the features of claim 1. In addition, the above objects are achieved by a method having the features of claim 11.

The generated ultrasonic waves are modulated in the invention by varying the laser pulse duration. In this case, the resolution increases with increasing frequency of the ultrasonic waves, but the penetration depth of the ultrasound into the tissue decreases. By varying the laser pulse duration of the laser radiation, it is possible to regulate the frequency of the ultrasonic waves generated and thus the penetration depth of the ultrasonic waves into a tissue or to change so that organ structures of different depths in the body under investigation can always be detected in an optimal resolution. The variation of the laser pulse duration or length takes place in dependence on the depth of the object in the body or on the distance between the body surface and the object in the interior of the body. Objects closer to the body surface, such as the thyroid gland or the female breast, are probed with ultrasonic waves that are higher in frequency than ultrasonic waves used to examine deeper-lying objects such as the liver or kidney. The frequency of the ultrasound waves produced can thus be optimized for a depth of the object to be examined in the body, wherein the optimization relates to the representation of the object in an optimal resolution.

The laser pulse duration can be continuously varied over a predetermined range, with each laser pulse duration being adjustable in the range. This requires a suitably trained laser or an appropriately designed laser source. This makes it possible to generate ultrasonic frequencies of any height in a given range. In this connection, the laser modulator is preferably designed for continuous variation of the laser pulse duration in the range of preferably 5 to 100 ns. In principle, however, it is not absolutely necessary to continuously change the laser pulse duration and thus the generated ultrasonic frequencies. For example, it is also possible to set or change the laser pulse duration stepwise or discretely in order to achieve a discretization of the ultrasonic frequency for different penetration depths. According to the invention, solid-state lasers, semiconductor lasers and dye lasers can be used for the induction of ultrasound. By suitable electrotechnical activation or by the use of optical and opto-mechanical components, a modulation of the pulse duration is otherwise possible. In addition, by integrating an active, controlled Q-switching module in the laser resonator, that is by modifying the laser hardware, the pulse duration can be changed. For the detection all common types of lasers can be used. Preferably, infrared semiconductor lasers can be used. Basically, however, cw laser other wavelengths can be used.

Preferably, laser beams with pulse durations in the range of 5 to 100 ns are used to induce ultrasound, so that the area of the so-called "thermal confinement" is not left. With a pulse duration of, for example, 50 ns, for example, ultrasonic waves with a frequency of approximately 10 MHz can be generated, which is important for medical imaging. The pulse repetition frequency should be in the range between 8 to 12 Hz, in particular at 10 Hz.

The analyzer also preferably comprises means for optically interferometric scanning of the surface of the body caused by reflected ultrasonic waves. In the invention, the surface modulation caused by the reflected ultrasound is detected directly by interferometer. The recording of the deformation of the surface of the body due to the reflected ultrasonic waves inside the body is carried out opto-electronically spatially and temporally resolved. As a result, the inner body structures can be detected with high accuracy.

In addition, it can be provided that optical and / or mechanical components are provided for the planar irradiation of the body by widening the laser radiation and / or for multi-beam illumination of the body by splitting the laser radiation. This results in a significant reduction in the time required for the examination of a body. Incidentally, optical and / or mechanical components for scanning the surface of the body with the laser radiation may be provided, wherein when the surface is scanned at least at two different locations of the surface. be generated or excited by laser irradiation ultrasonic generating centers. By scanning the surface of the body, it is possible to fully examine the internal structures of the body in a small amount of time. This, of course, assumes that the analyzer is designed to detect the echoes of the ultrasonic waves emanating from different ultrasound production centers in an interferometric manner.

In a further preferred embodiment of the ultrasound diagnostic device according to the invention, means for tomographic representation of the internal spatial structure of the body can be provided by using depth information of the body, the depth information being obtainable by evaluating the detected echoes of ultrasound waves of different frequency. The tomographic visualization allows a three-dimensional reconstruction of internal structures of the body, for example of specific organs or specific body distances. Moreover, it allows the invention to produce sectional images of a complete organ or a specific body portion, which requires a corresponding design of the ultrasonic diagnostic device.

The invention makes it possible, if necessary, to combine the features mentioned in the claims and / or the features disclosed and described with reference to the drawing, even if this is not described in detail. The invention is not limited to the illustrated and described embodiment of an ultrasonic diagnostic device. Moreover, the features mentioned in the dependent claims may also be provided in such ultrasonic diagnostic devices that do not allow any variation of the laser pulse duration. The features mentioned in the dependent claims therefore each ownfinderische meaning.

Ultrasound reflected from vessels, organs and tissues is detected interferometrically on the skin surface of a body in the method according to the invention and evaluated by electronic means. The high penetration depths of ultrasound in biological media and the high spatial resolution are combined with the good contrast of optical methods. By contrast, purely optical imaging systems are restricted directly to skin surface areas. Furthermore, the inventive method ensures a contact-free scanning of the points to be examined on the object. The invention enables automation and consequent standardization of organ and vascular diagnosis. In addition to significant cost reduction and ease of use, the new method offers the greatest possible spatial resolution and non-invasive and non-contact detection of the structures to be examined. The frequency of the pulsed laser light used is not critical per se; Laser light can be used in the infrared, visible and ultraviolet ranges. The laser energy used can range from low-energy to high-energy pulsed lasers. However, a safety limit for human skin of about 200 mW / cm ² should not be exceeded.

The term "body" in the context of the invention comprises animal and human bodies, in particular bodies of mammals, more particularly of escorts, domestic animals, utility animals and laboratory animals. The invention allows a pictorial representation of the internal structure of a body of living things, in particular of internal organs and tissue structures, for example of blood vessels. The ultrasound diagnostic device according to the invention is suitable not only for the clinical examination of human and animal patients but also for use in preclinical research to investigate the influence of new drugs on the organisms or their functionality in laboratory animals. The device according to the invention is particularly suitable for detecting and displaying deeper regions in bodies, in particular for detecting and displaying body organs and lower-lying blood vessels.

Preferred embodiments of the ultrasonic diagnostic device according to the invention are those

(A) which have a laser modulator, which is designed for free adjustment of the pulse duration or pulse length and optionally for regulating the laser intensity;

(b) which optical and / or mechanical components for dividing the laser light in each case for interferometric detection and ultrasound generation;

(c) having a free jet arrangement in which the laser light is irradiated on the body to be examined; (d) which comprise means for generating and / or shaping interference-capable coherent laser beams;

(e) having means for spatially and temporally resolved recording of interference patterns;

(f) having ultrasonic generating means for generating ultrasonic waves on the surface of the body and interferometry means for interferometrically detecting and evaluating echoes of the generated ultrasonic waves, the ultrasonic generating means and the interferometry means being arranged to produce and visualize slice images of the body can; (g) having means for computer and software-based recording, storage and evaluation of the interference patterns and optionally image processing and display devices;

(H) which have an arrangement provided in the means for the protected illumination of the body from harmful laser radiation

(i) having an arrangement in which the means for irradiating the body with the laser light comprise a light guide to guide the laser beam and the laser radiation without loss and risk;

(J) which have an arrangement in which means are provided for the movable arrangement of the light guide for generating point or area ultrasound generating centers in the body by one-, two- or three-dimensionally screened irradiation of the body;

(k) which have an arrangement in which means for beam expansion are provided for the planar irradiation of the object;

(1) which have an arrangement for the automated, electronically controlled guidance of a laser and beam shaping unit in all spatial directions;

(m) wherein, preferably, by means of a grid-like movement of the laser and beam-shaping unit and / or the body, a multiplicity of generating points for ultrasound can be excited;

(n) which modulators have for preferably continuous modulation of the frequency of the induced ultrasound via the variation of the laser pulse duration or laser pulse length of the laser or the laser pulse duration or laser pulse length of the laser or the generated laser radiation for regulating the penetration depth of the ultrasound in the biological tissue.

Further preferred are such embodiments of an ultrasonic diagnostic device,

(i) which means for increasing the reflectivity of the surface for a

Signal laser beam, wherein the surface is modulated by reflected ultrasound; if the reflectivity of the skin surface is not sufficient for the laser radiation used, the reflection of the skin surface can be improved by applying a nano-metal powder, a foil, a gel or a spray with appropriate substances. Basically, however, the reflection on the skin is sufficient, so that preferably an increase in the reflectivity is not provided. Something else may apply if the reflection of the signal beam to the skin back into the interferometer is insufficient, which can be the result of burns or occurs on very rough skin;

(ii) have arrangements in which means for beam expansion, beam deflection, beam guidance, beam splitting and / or intensity regulation are provided; (iii) having arrangements in which the ultrasound-based echo signals from within the body modulate the surface of the body, the echo signals being generated in the body and being formed by reflected ultrasonic waves; (iv) having arrangements in which the optical signal beam irradiates the modified body surface and temporally and spatially modulates the optical phase in correlation with the surface modulation; (v) which have arrangements in which means are provided for interferometrically superimposing the phase-modulated optical signal beam with a reference optical beam; (vi) having arrangements in which means are provided for optoelectronic recording of the interference signals with sufficient time and space resolution; (vii) which have arrangements in which laser radiation of a plurality of laser wavelengths from a plurality of laser sources is used to improve the spatial resolution;

(viii) having arrangements using the same laser source for ultrasound generation and interferometric detection;

(ix) which has arrangements in which means for dividing the laser radiation from the same laser source are respectively provided for ultrasonic generation and for interferometric detection;

(x) the ultrasonic generating device and the interferometry device being integrated into a common system; (xi) which have arrangements which allow the detected interference reflex patterns of the different tissue structures to be detected and visualized, wherein, preferably, the visualization of the structure, arrangement and nature of the body is computer-assisted;

(xii) which detectors for determining gradients of blood flow velocities using the Doppler shift method in the frequency of the detected ultrasound, preferably of lower-lying blood vessels, in particular in order to localize, visualize and quantify narrowed and intact blood vessels;

(xiii) which have arrangements in which means are provided for protecting the body from the laser radiation; (xiv) which have arrangements in which means are provided for electronic or printed representation of the body and its internal structure, properties and nature;

(xv) which have arrangements allowing the body and its internal structure, properties and composition to coincide with the body

Measuring process, that is in real time, represent; (xvi) which have arrangements that allow to automate the complete and / or partial examination and its presentation.

In the drawing show

Fig. 1 "is a schematic representation of an arrangement for generating

2 shows a schematic representation of an arrangement for the areal and / or pointwise optical scanning of the modulation of the surface of the body, caused by ultrasonic waves reflected by internal body components by means of an interferometer, FIGS

Fig. 4 is a schematic representation of the generation of ultrasonic waves in the body by means of laser radiation and the detection of reflected ultrasonic waves by means of interferometry.

FIGS. 1 to 4 show a body 1 to be examined with a body limb 12, as a rule the skin, and internal organs 13 or vessels and tissue.

In Fig. 1, an ultrasonic generating device 2 is shown with means for generating and deforming laser light. The ultrasonic generating device 2 comprises a laser source 21, a drive 22 for the laser source 21 and a beam shaping unit, which can have means 23 for beam expansion, means 24 for beam deflection and means 25 for intensity regulation.

FIG. 2 shows an interferometry device 5 for the optical detection of an echo signal of the generated ultrasound, which has a laser source and beam shaping unit 3 and an interferometric detection unit 4. The laser source and beam shaping unit 3 has means for generating and deforming the laser light for the interferometric detection of ultrasound. The laser source and beam shaping unit 3 has, in particular, a laser source 31 and a drive 32 for the laser source 31, and a beam shaping unit, which can include means 33 for beam expansion, means 34 for beam deflection and means 35 for intensity regulation. The detection unit 4 may have means 45 for beam splitting, means 42 for optoelectronic detecting the optical reference pattern and an electronic computer unit 41 for evaluating and displaying the body information.

In a first. Process step is irradiated to the skin surface 12 for generating ultrasound according to FIG. 1 laser radiation 26 of the laser source 21, preferably pulsed laser radiation with short laser pulses. The pulse duration of the laser radiation 26 can be changed and controlled or adjusted by the control 22. The laser-induced thermal expansion of the light-absorbing structures in the tissue of the body 1 generates according to Fig. 3 acoustic waves 61 by thermoelastic mechanisms, wherein the generated acoustic frequencies are mainly in the ultrasonic range. The frequency of the ultrasound generated in this way is directly proportional to the laser pulse duration of the irradiated laser radiation 26, so that a continuous modulation in the frequency of the generated ultrasound 61 is made possible by a variation of the laser pulse duration of the laser source 21. The ultrasound generating device 2 is preferably arranged so as to be movable relative to the body 1 and rests with the laser beam 26 one-dimensionally or two-dimensionally on the surface of the body 1 to be examined. Optionally, the laser source 21 can be fixed and the laser radiation 26 can be deflected via optical and / or mechanical components 24 toward the body 1 in accordance with a predetermined pattern. About the frequency of the ultrasound 61, which can be varied over the pulse duration of the laser beam 26, different penetration depths can be achieved in the tissue. This makes it possible to detect depth information about the internal structure of the body 1 in the axial direction. This allows a spatially resolved three-dimensional image of the internal organs 13 of the body 1, which requires a corresponding design of the ultrasound diagnostic device.

The illustrated ultrasonic diagnostic device provides interferometric detection of the reflected ultrasound by means of sufficiently coherent light. The local generation of ultrasound waves 61 on the skin surface and the optical detection of the reflected ultrasound waves 62 by means of interferometry make it possible to decouple the ultrasound generation device 2 and the interferometry device 5. In addition, an adapted sound transmission medium, such as a gel layer, can be dispensed with. whereby further the working distance between the measuring unit and a body 1 can be freely selected.

The ultrasonic waves 62 reflected by the organs 13 propagate to the skin surface 12 and modulate them mechanically according to their amplitudes and frequencies. The deformation of the skin surface 63 takes place in spatial and temporal correlation to the amplitudes and propagation delays of the reflected primary ultrasonic waves 62. This is shown in FIG.

In a further method step, the topology of the deformation is detected according to the invention optically spatially and temporally resolved interferometrically. For this purpose, the coherent laser beam 36 of a second laser 31, for example a cw laser or a sufficient proportion of the laser radiation 26 of the ultrasound-generating laser source 21, which is branched off with the aid of optical elements, is coupled into an interferometer unit 4. The interferometer unit 4 comprises the described light source as well as optical and mechanical components and an optoelectronic transducer 42. The laser beam 36 according to FIG. 2, which can either start from the second laser 31 or be branched off from the laser source 21, is replaced by optical components 33 expanded as needed and divided by further optical and / or mechanical components 45 in a reference beam 44 and in a signal beam 43. The signal beam 43 transilluminates the skin surface 63 at points or areas and undergoes a deformation modulation correlated phase modulation. Superposition of the signal phase modulated in the optical phase signal beam 43 with the reference beam 44 leads to characteristic interference patterns, which are recorded with an optoelectronic transducer 42 with respect to the time and location-dependent light intensity or light amplitude. The interferometry device 5, which is preferably movably arranged in three spatial directions, permits a scanning of the entire body 1. This can optionally be done sequentially. The ultrasound generating device 2 and the interferometry device 5 can be arranged movably relative to one another and / or movable relative to the body 1. For example, in a profile measurement of the body 1, the ultrasound generating device 2 and / or the interferometry device 5 can be moved annularly in order to scan a profile of the body 1. The temporally and spatially resolved recorded interference patterns include information about the amplitudes and frequencies of the reflected ultrasonic signal, as well as transit times and frequency shifts, filtering out overlays of the induced and reflected signals. This filtering can be achieved by a preceding calibration measurement.

The resolution of the interference signal depends primarily on the wavelength of the laser used and on the quality of the optoelectronic converters, in particular the signal / noise ratio of the intensified CCD (Charged Coupled Device). In order to increase the axial resolution or the uniqueness range, the so-called free-spectral range, it is possible to work with several laser wavelengths. For example, it is provided to partially divert the pulsed laser beam 26 of the laser source 21, which induces the ultrasonic waves 61, for this purpose or to use white light interferometers. The interferometer arrangement, for example "Fabry Perot", "Michelson", "Mach-Zehnder" or the like, is freely selectable as required.

The ultrasound generation and the detection of echoes of ultrasound waves 61 by means of lasers have significant advantages over conventional methods involving the use of piezocrystals for ultrasound generation and detection: continuous frequency modulation is possible, whereby the penetration depth in the biological medium can be controlled. The gel layer for the reflection-free transmission of ultrasound into the tissue is eliminated, whereby a detection can take place even in a vacuum. Furthermore, the working distance between the body 1 to be examined and the detector or the ultrasound generating device 2 and the interferometry device 5 can be freely selected. Incidentally, measurements can be performed on moving bodies 1.

For the evaluation and visualization of the functional and structural properties of the examined body 1, the punctually sampled or areal recorded interference patterns are analyzed by means of software and computer equipment. The temporally and spatially resolved recorded interference patterns include the temporal and spatial modulation in the phase of the signal beam 43 in the form of generally high-frequency amplitudes, which are directly correlated with the mechanical surface modulation of the body 1, which differs from that of the interior of the body 1 reflected ultrasound. The requirement for the optoelectronic converter includes, inter alia, a sufficient chronologically and spatially resolved recording of the intensity fluctuations for the purpose of separating the frequency shifts which are caused by the interior of the body itself and the frequencies of the carrier sound waves. The properties of the reflected ultrasound are inter alia functions of the nature, in particular of the material and the density, the structure, in particular the morphology, and the state, in particular the movement, for example of blood bodies, inside the body 1. By computer and Software-based extraction of the transit time differences and sound intensity from interference patterns resulting from the different reflection and transmission properties and sound velocities of different organs and tissue structures, the visualization of the interior of the body.

With the evaluation of punctual interference recording, information is obtained for the representation of a body point. By a two-dimensional punctiform screening of the body level as well as by the modulation in the frequency of the ultrasound achievable depth information can be made a three-dimensional visualization of the internal structure of the body 1 body. If necessary, a flat interference pattern can be generated by a broadened laser beam 36, wherein the broadening of the laser beam 36 can be carried out by the means 33. This reduces the examination time. For this purpose, optoelectronic transducers are provided with a sufficient fill factor.

The entire measuring unit of ultrasound generating device 2 and interference device 5 can be integrated in a closed housing or arranged in separate units for ultrasound generation and detection as well as for the evaluation of the measurement. Optionally, the measuring unit, in total or in part, can be moved automatically and electronically controlled, keeping the body 1 at rest. In addition, it is possible that the body 1 moves and the measuring unit, in whole or in part, is kept at rest.

For the visualization of blood vessels and constrictions in the body 1, the evaluation of the Doppler shift in the frequency of the reflected ultrasound is provided. Moving objects, such as blood cells, change them Input frequency of the ultrasonic wave 61 proportional to its direction of movement and speed. According to the invention, it can therefore be provided to determine the speed of the blood cells by means of a comparison of the input ultrasound frequency, whose determination is preceded by a calibration measurement, as well as information on the geometry of the vessels, on the degree and on potential velocity gradients to find out about the location of possible constrictions and to visualize them computer-aided.

Claims

claims:

1. Ultrasonic diagnostic device, comprising at least one laser source (21, 31) and at least one analyzer, wherein the laser source (21, 31) by means of pulsed laser radiation (26) on the surface of a body (1) ultrasonic waves (61 ) and wherein in the analyzer, the echo of the ultrasonic waves (61) is detected and evaluated interferometrically, characterized in that a laser modulator is provided and that the laser modulator for varying the laser pulse duration of the laser radiation (26) is formed, the laser pulse duration for Changing the frequency of the generated ultrasonic waves (61) is adjustable to at least two different laser pulse durations.

2. ultrasonic diagnostic device according to claim 1, characterized in that the laser modulator is designed for continuous variation of the laser pulse duration in a predetermined range.

3. ultrasonic diagnostic device according to claim 2, characterized in that the laser pulse duration in a range of 1 to 200 ns, in particular from 5 to 100 ns, is adjustable.

4. Ultrasonic diagnostic device according to one of the preceding claims, characterized in that the analyzer at least one means for detecting the reflected ultrasonic waves (62) by means of optical, interferometric scanning of the reflected by and / or scattered ultrasonic waves (62). caused modulation of the surface of the body (1).

5. Ultrasonic diagnostic device according to one of the preceding claims, characterized in that optical and / or mechanical components for planar irradiation of the body (1) by widening of the laser radiation (26, 36) are provided.

6. ultrasonic diagnostic device according to any one of the preceding claims, characterized in that optical and / or mechanical components for multi-beam illumination of the body (1) by splitting the laser radiation (26, 36) are provided.

7. Ultrasonic diagnostic device according to one of the preceding claims, characterized in that optical and / or mechanical components for scanning the surface of the body (1) with the laser radiation (26) are provided, wherein in the scanning of the surface at least two Different areas of the surface are excited by laser irradiation ultrasonic generating centers.

8. Ultrasonic diagnostic device according to one of the preceding claims, characterized in that means for tomographic representation of the internal spatial structure of the body (1) by using depth information of the body (1) are provided, wherein the depth information by evaluation of the detected echoes of ultrasonic waves (61) with different frequencies are available.

9. ultrasonic diagnostic device according to any one of the preceding claims, characterized in that optical and / or mechanical components for dividing the laser radiation (26) are provided for an interferometric detection and for ultrasound generation.

10. Ultrasonic diagnostic device according to one of the preceding claims, characterized in that an ultrasonic generating device (2) for generating ultrasonic waves (61) on the surface of the body (1) and an interferometry device (5) for interferometric detection and evaluation of the echo the generated ultrasonic waves (61) are provided, wherein the ultrasonic generating means (2) and the interferometric means (5) are arranged movably relative to each other and / or movable to the body (1).

11. A method for non-invasive, two- and / or three-dimensional representation of the internal structure of a body (1), wherein ultrasonic waves (61) by means of pulsed laser radiation (26) on a surface of the body (1) are generated, wherein the Echo of the ultrasonic waves (61) is detected and evaluated interferometrically by means of laser radiation (26, 36) and wherein the laser pulse duration of the laser radiation (26) for varying the frequency of the generated ultrasonic waves (61) is varied.

12. The method according to claim 11, characterized in that the laser pulse duration is varied continuously in a predetermined range, in particular in a range of 5 to 100 ns.

13. The method according to claim 11 or 12, characterized in that a caused by reflected and / or scattered ultrasonic waves (62) modulation of the surface of the body (1) is scanned optically, interferometrically.

14. The method according to any one of claims 11 to 13, characterized in that the laser radiation (26, 36) for a planar irradiation of the body (1) is widened and / or split for multi-beam illumination of the body (1).

15. The method according to any one of claims 11 to 14, characterized in that are excited by scanning the surface of the body (1) with the laser radiation (26) at least two different locations of the surface by laser irradiation ultrasonic generating centers.