Device for endoscopic diagnostics and for treatment of tissue

The invention relates to a device for the endoscopic diagnosis and treatment tissue according to the features specified in the preamble of claim 1 Features.

Endoscopic devices of the type mentioned - cine such device is known for example from US Patent No. 5,413,108 - are nowadays applied for example in the sigmoidoscope. It is a slender distal End portion of a generally flexible endoscope through a body orifice in mono- the body to be diagnosed and to the site to be treated or be led. The tissue to be diagnosed region, such as the intestinal wall, is by at least two diagnosis lasers of different wavelengths irradiated, after which the remitted light - either through reflection or by Fluorescence - is dependent on the wavelength detected. The received signals pixel depending linked by subtraction or quotient, whereby the topology of the fabric to be diagnosed portion off becomes. It will be through these electronic signal combinations Differences in intensity of the received image, such as for example by Shadow, elevations, depressions and the like arise off. The remaining image or electrical signal allows due to the wavelength-dependent Remission phenomena of healthy and malignant tissue, desired diagnosis. After diagnosis the malignant tissue can directly evaporated by a laser treatment, be so removed. Use the diagnostic laser can then be carried out immediately to check whether the malignant tissue has been completely removed or not.

The device structure of this moderate from the US Patent 5,413,108 known Arrangement is such that both the diagnostic and treating laser, and the receiving devices outside of the endoscope are and via optical fiber are connected to the distal end of the endoscope. The wavelength separation takes place via filters, which are in an engaging into the beam path disc, which is driven by a motor.

A similar arrangement is known from US-PS 5,309,895. There is a CCD disposed in the distal end of the endoscope to the highest possible light yield achieve, but the light signal received in this device is still weaker because the lighting is only periodically.

A similar arrangement is known from GB 2125986 A. In this device, is does not pass out of the treatment laser by a separate working channel, but already intergriet.

A disadvantage of the aforementioned devices is particularly complicated and technically complex construction. The light emitted by reflection or fluorescence Light is extremely weak and must therefore technically complicated manner be amplified before it can be received and evaluated. this leads to ultimately, that the diagnosis means a relatively low sensitivity has or does not operate with the necessary reliability. In addition, arise in the prior art devices in both the Diagnosis as well as in the therapy often problems as regards the accuracy the diagnostic or therapeutic area.

Starting from this prior art, the invention has the object, a generic device in such a way that on the one hand, a high Accuracy and sensitivity, but on the other hand, a low-cost and robust construction is achieved.

This object is according to the invention by the characterizing part of dissolved claim 1 specified characteristics.

Accordingly, the invention provides timely solution at least one scanning device before which guides the light of the diagnosis laser over a diagnosis field, and a photodiode as a receiving device. It is thus not the same entire diagnostics field irradiated, but the laser beam by the scanning device by type of flying-spot method performed via the diagnostic field. This results in certain points in the diagnostic field as compared to the prior art when using a comparable diagnostic laser substantial higher illuminance. This requires a stronger widerrum remission why the signal received by the receiving means stronger and therefore less consuming is in the recording and further processing.

This effect is exacerbated by the fact that as a receiving device for the each diagnosis laser not a CCD, the same time the remission of entire diagnostic field detected is used, but a photodiode. These Photodiode, which in comparison to a CCD a substantially larger angle of aperture and thus has a much higher sensitivity, receiving time seen only the remitted light or the fluorescence of the point of the diagnostic field, which is being irradiated by the scanning device. So it turns out also receiving device side, a substantial stronger signal, because the entire remitted light from only one or, for example, three if three three diagnosis lasers each provided with its own receiver werden- photodiodes is added, resulting in a much stronger and lower-noise signal leads, as a comparison, if a CCD is used in which the light remitted Light is distributed over a wide range of photographic elements.

The image-wise evaluation is carried out in the inventive device means the control and evaluation device, in dependence of the time, as each Received signal time-dependent a certain pixel in a pixel matrix can be assigned, according to the respective position of the scanning device. Furthermore, this arrangement allows integration of autofocus device without using additional photodiodes.

The invention provides for the receiving device, or when using several Receiving devices in this distal end portion of the endoscopic Part of the apparatus to arrange. This allows the by fluorescence or Reflection of light emitted by the shortest route and avoiding costly optical devices are fed to the receiving devices so that to the usual elaborate amplifier can be dispensed with. The light guide within the distal end portion of the light input to the receiving device can generally take place exclusively via mirrors, so that a Most of this light, the receiving device or the receiving devices can be supplied. It is particularly important that by the use the usual light guides in the range between light input and receiving device can be completely dispensed with, whereby the usual small Acceptance angle substantially increased and thus the coupling losses throughout can be significantly reduced. The inventive apparatus has thus already constructed for substantially higher sensitivity than known from the prior art, wherein the construction already characterized significantly cheaper and easier is that the usual light amplifier can be dispensed with entirely.

The accuracy in the diagnosis and therapy place, according to the Invention further be increased by the fact that the beam paths of the light emitted and incident light at the distal end of the device, ie, the beam paths brought from diagnosis and treatment laser in accordance will. The merging of the beam paths has also constructive Advantages and allows a slim design of the device in particular in the distal end region.

In principle, the inventive device can with a diagnostic laser and a receiving device to be operated if both of the diagnosis laser and the receiving device are employed clocked to a generated and received certain time interval light of a first wavelength and generating for a further time interval light of a second wavelength and is received, as it is for instance described in US Patent No. 5,413,108. However, this may in extreme cases lead to motion blur, which is why is proposed according to the invention preferably, at least two diagnosis lasers provide different wavelength and each diagnosis laser in a distal end portion of the apparatus arranged receiving means assigned. Then both diagnostic laser can be operated simultaneously, in accordance with the receiving is performed so that when the electronic signal combination topology elimination always a near real-time image.

For many applications, the evaluation by means of widely differing absorption / reflectance the two diagnostic wavelength ranges advantageous. suffice here to eliminate the topology of the irradiated tissue area in principle the Irradiation of two different wavelengths and a corresponding Evaluation. In some applications, however, it is also advantageous if three Diagnosis lasers of different wavelengths are provided, which preferably the wavelength ranges red, green and blue cover. Then, namely with those obtained from the light reflected light reception signals in these three wavelength ranges additionally a natural color image, for example on a monitor being represented. The attending physician can thus in addition to the calculation by Subtraction, quotient formation or otherwise suitably formed diagnostic image his collected from the natural viewing screen experience bring.

To obtain an accurate, high-resolution diagnostic image, diagnostic laser beams led to the type of flying-spot method with a diagnostic field, opens into the center of the beam path of the laser therapy. To make this reached, the apparatus advantageously within the distal end portion Scanning devices on which the laser beams of the laser diagnosis before Impinging horizontally and vertically deflect. The respective deflection electronically captured, so that the diagnostic field time-dependent specific diagnostic points can be assigned. Accordingly, the signals of the receiving devices linked so that an image-forming dot matrix is ​​formed which by frequente query, for example, three times per second, as a picture Monitor can be supplied, which regardless of the sampling rate, for example, 50 or 100 Hz to obtain a quiet image can be clocked. Such Microscanner are known per se. It is in this context to "Microsystems Technology 1994-1999, program under the Institutional Strategy Information Technology ", published by the Federal Ministry for Research and Technology - Public Relations from January 1994 (ISBN 3-88135-276-7) referenced, there particularly on page 81. These are semiconductor mirror, which are arranged in the manner of a rocker and on the bottom electrode , such that a rocking movement by electromagnetic actuation carried out for one or the other direction. These mirror usually operated in the resonance range, so that the evaluation electronics only adapt to the resonance frequency. Moreover, it is also possible these mirrors through specific electromagnetic actuation of the one side or another specifically to move to the desired scanning effect to achieve, ie the point of impact of a laser beam diagnostics in the diagnostic field specifically influence.

However, for localized diagnostics, it is also advantageous if each Diagnostic laser receiving means is associated with the selective only to the Receiving the light is provided the wavelength emitted by this laser, becomes. A particularly beneficial arrangement to obtain an intense and well detectable signal arises when the receiving devices are arranged inside the distal end portion, between the distal end of the device and the scanning devices. The reception takes place with conventional (relatively large) photodiodes, so that as the received signal always the whole remitted by the tissue light of the particular diagnostic laser is available. The evaluation as a matrix of pixels is carried out in accordance the temporal assignment of the individual pixels.

Structurally, it is particularly favorable if each receiver, a photodiode is assigned, wherein the wavelength-dependent splitting of the remitted Light in a conventional manner through semipermeable, dikroitisch can be done coated prisms or prism arrays. Advantageously the Evaluation of the received signals with the release or trigger control linked treatment laser, so that, for example, a triggering of the treatment laser is only possible when a predetermined (malignant tissue Signing) threshold in the comprehensive treatment laser Image area is exceeded. On the other hand, an active engagement in the Control of the treatment laser effected such that an automatic triggering takes place when a predetermined threshold value is exceeded.

particularly convenient for the practical use of the device is the provision of a known autofocus device. This autofocus device can with substantial use of existing components in the distal end portion be integrated, even if the beam path with the laser diagnostics and the treatment of the laser in the distal end of the device coincide. Preferably, the focusing lens of the autofocus device is in arranged distal end portion in front of the distal exit window and by example, a conventional coil arrangement by electromagnetic Acted upon in the axial direction of the beam path for the purpose of focusing displaced.

Preferably, the auto focus means cooperates with the most intense remitted Wavelength range (lowest absorption z. B. 1.3 microns in the infrared range and 0.35 .mu.m in the UV range), for which purpose the corresponding diagnosis from the laser emitted light can be used when a corresponding time clocking between required for the autofocus device and receiving required for diagnosis reception takes place. In this case, the also form part of the autofocus device photodiodes of the receiving devices. This not only leads to an inexpensive and space-saving training the endoscopic end portion, but also to an especially high accuracy the autofocus device and thus a high accuracy throughout the Device.

The invention is described below with reference to embodiments shown in the drawing explained in more detail. Show it:<dl tsize="7"><dt>Fig. 1</dt><dd>a simplified block diagram of the device according to the invention,</dd><dt>FIG. 2</dt><dd>in a highly simplified schematic representation of the invention Device with depicted in longitudinal section distal end portion,</dd><dt>Fig. 3</dt><dd>another embodiment of the distal end portion in longitudinal section, and</dd><dt>Fig. 4</dt><dd>a further embodiment in view of FIG. 3</dd></dl>

The apparatus of Figure 2 has a laser treatment. 1 It deals This is a 1.06 in <i>μ</i>m area working Nd-YAG laser. The light of the treatment laser 1 is passed through a multi-mode fiber bundle 2, which in a distal end portion 3 of a here not shown in detail and described endoscopic instrument, such as a flexible Endoscope similar to that known from US Patent No. 5,413,108, opens. Outside the endoscopic instrument remain an electronic evaluation and Control unit 4 as well as two diagnosis lasers 5 and 6 are arranged. Each diagnostic laser is a composed of two prisms beam splitter block 8 with a receiving means connected for light remitted in the form of a photodiode. 7 The Diagnostic laser 5 and 6 with their associated photodiodes 7 are in turn a common partially mirrored prism 9 in the same beam path of a single-mode fiber 10 coupled, which also opens into the distal end portion of the third The Diagnostic Laser 5 and 6 operate in this embodiment in a Wavelength range of 1.31 <i>μ</i>m and 1.55 <i>μ</i>m, which is a magnitude to Factor 10 have different absorption and therefore remission in the tissue. Similar differences can be achieved in the UV range (0.2 <i>μ</i>m and 0.35 <i>μ</i>m wavelength). The laser 5,6 are configured as laser diode, wherein of the 1.31 <i>μ</i>m area working laser 5 at substantially the topology detection of the tissue region to be examined is used, while the in the 1.55 <i>μ</i>m area working laser 6 for detecting topology and tissue-specific Considerations serves.

The entering via the single-mode fiber 10 in the distal end portion 3 Laser beams of the diagnosis laser 5 and 6 are within the end portion 3 via suitable mirror arrangements initially a vertical scanner 12 and below a horizontal scanner 11 fed. In the scanners 11, 12 If it is silicon two-axis scanner that because of electromagnetic swing excitation in a predetermined frequency about an axis. The Axes of the scanner 11 and 12 are arranged so that from the single-mode fiber 10 light beams coming in two mutually offset by 90 ° planes get distracted. This deflection the point light beams directed to a substantially square box. Since the oscillation the scanner 11 and 12 by electromagnetic excitation and the Oscillation frequency is known, a temporal allocation of the scanner take place, so that within the electric control unit 4 is assigned, on which point the aforementioned approximately square field, the light beams are currently facing.

From the scanners 11 and 12, the light beams of the diagnosis laser 5 and 6 are wavelength-dependent over a prism block each 13 a beam splitter block 14 is supplied, and then in a further distally disposed prism block to be 15 reunited. About a distally underlying prism block 16 is then in this beam path of the diagnostic laser 5, the beam path of the treatment laser 1 engaged. This common beam path 17 passes through a lens 18, an autofocus device, before the distal side via Windows 19 the distal end portion 3 of the device leaves. The lens 18 is a coil arrangement, as in auto-focus devices customary in movable axially of the beam path 17th

The light emerging from the light window 19 of the diagnosis laser 5 and 6, the means of the scanner 11 and 12, a diagnosis field sweeps through, is to be examined by the Material, in particular tissue, remitted and passes through the window 19, the lens 18, the prism block 16 to the prism block 15, where a wavelength-dependent Splitting occurs. About the beamsplitter blocks 14 which is remitted Light then depends on the wavelength photodiodes 20 which are also part the autofocus device is. The autofocus device operates in time windows, in which the diagnostic and therapeutic function is interrupted, taking advantage the light reflected from the diagnosis lasers 5 and 6 on the object light. By shifting the lens 18 is by means of the photodiode 20, the intensity maximum of the reflected light, and thus the optimal focusing position of the lens 18 determined.

Outside this time window, enters the light generated by the diagnostic lasers 5, 6 and the object remitted light through the beam splitter blocks pass through the Prism block 13 to the scanners 11, 12, which via the prism 9 back to the Beamsplitter blocks 8 throw where it means the photodiode 7 in its intensity is detected. The signal from the photodiode 7 is the electrical evaluation and Control unit 4 is supplied, in which a pixel assignment according to the current scanner position in the diagnostic field and thus the construction of a of Pixels existing matrix takes place, namely wavelength dependent, to one for the remitted by the diagnostic laser light 5 and the other for the Diagnostic Laser 6 remitted light.

The signal processing within the control unit 4 is based on the in figure 1 Block diagram represented illustrated. The signal from the photodiode 7 is in each case first passed to an analog-to-digital converter 21st The digital Output of this analog-to-digital converter is again a central Image processing unit 22 supplied. In this image processing unit 22 are of the photodiodes 7 digitized data using the synchronization data Scanner 11 and 12 for a wavelength dependent on of single pixels built Bildmatrizes processed the extent that they of the remitted light Diagnostic laser 5 as submitted, an image memory A and, as far as they remitted from Light of the diagnostic laser 6 as submitted, an image memory B are supplied.

Furthermore, in the central image processor unit 22, the wavelength-dependent Image data linked mathematically, namely either by subtraction or by forming a quotient. The resulting mathematically determined image is a Image memory C supplied. While the frame memory A and B for substantially to access the central image processing unit for determining the values ​​of the serve image memory C and only selectively on a monitor 23 can be displayed, is the image memory C at regular intervals, for example, three times Second, retrieved from an analysis unit 24, while the loop-through Signal processed in a video unit 25 and displayed on the monitor 23 becomes. On the monitor 23 so is the mathematically linked image of the image memory C illustrates the topology is adjusted, ie only shows an image see in particular the contours between malignant and healthy tissue leaves. By selectively turning on the images A and B can, if desired, the topology are displayed alone or in addition.

Within the analysis unit 24 takes an electronic evaluation of the image C, especially in the central region, the straight from the treatment laser 1 is covered. In response to a predetermined, previously adjustable threshold value, a signal to the controller 26 of the treatment laser 1 is discharged. The control unit 4 may be switched so that the controller 26 with a pending Signal analysis unit 24 automatically turns on the laser treatment 1 or a release of a manual control of the treatment laser 1 takes place, which is to control the attending physician. In this way reliable to prevent the treatment laser 1 by mistake, for Example will be triggered when only been diagnosed healthy tissue is. Only at a predetermined by setting the threshold minimum salary of malignant tissue in the diagnostic window, the triggering of the treatment laser done and done this automatically.

The monitor display is always with a repetition rate of 50 or more Hz, however, the sampling frequency of the image memory significantly lower may be, for example, three times per second. In this way, remains the Image processing unit enough time to the staggered next pixel data compile an overall picture and to process computationally. in the Incidentally, the monitor display by the windowing for autofocus not impaired, is nevertheless locked in this time of the treatment laser.

Execution based illustrated by Figure 3 differs from the above characterized in that the beams of the diagnosis laser 5 and 6 by means of separate Single-mode fibers are guided to the distal end portion 3 ', where they an appropriate prism array are merged 27th From there they are in turn, a vertical and then a horizontal scanner 12 and 11 supplied. From there first takes place again by corresponding prism assembly a wavelength-dependent beam splitter. is in beam splitter blocks 28 on photodiode 29, the intensity of the 5 and 6 extending from the diagnostic lasers Light is measured. This detection of the incident diagnostic performance can be used in the control unit 4 intensity fluctuations of the diagnosis laser 5 and 6 be compensated, thereby preventing further potential source of errors excluded becomes. The beams then pass through another beam splitter blocks 30 to a prism array 31, in which the beams of both diagnostic laser 5 and 6 reunited and with the beam path of the treatment laser 1, which also is connected through a multimode fiber bundle 2 with the distal end portion 3 ', coupled. The common optical path of diagnostic lasers 5, 6 and laser treatment then 1 performs in this embodiment to the longitudinal axis of the distal End portion 3 'slanted lens 18 to the likewise inclined distal window 19. In this embodiment, the lens 18 is part of an autofocus device, provided at its outer periphery with a coil arrangement and slidably disposed in the axial direction. The one with the coil assembly cooperating permanent ring magnet with the reference number 32 in Figure 3 in.

In contrast to the embodiment according to Figure 2, the photodiodes 7 for detecting the intensity of the reflected light in the embodiment of Figure 3 'Disposed within the distal end portion 3, namely at the bottom of Beamsplitter blocks 30. Here, since the intensity measurement before passing the Scanner 11 and 12 is carried out, the measurement made much easier because the an intensity of the reflected light is even higher and other through the entire surface measuring a considerably larger amount of light Measurement is available. To that extent, this arrangement is opposite the be preferable based on Figure 2 shown.

are also in the third embodiment illustrated with reference to FIG 4 the photodiodes 7 within the distal end portion 3 ". The structure the distal end portion 3 "essentially corresponds to the reference to FIG 3 shown, for which reason this is not described again here in detail is, it is understandable based on the same reference numerals used. In the the stated figure angle α, β and γ are there chosen as follows: <sl><li>α about 22.5 °,</li><li>β approximately 33.75 °,</li><li>γ approximately 45 °.</li></sl>

The angles α and β are identical to those of the embodiment of FIG. 3

The main difference to the previously described embodiment is that three diagnostic laser, 5, 6 and 33 is provided. The wavelengths of these three Diagnostic laser are selected so that a laser in the red range, a green laser in the area and working in the blue range, so that the rays to natural add white light. Accordingly, the prism arrays are modified and there are three photodiodes 29 for detecting power fluctuations in the Diagnosis lasers and three photodiodes 7 for wavelength-dependent intensity determination provided. The control unit 4 is adjusted accordingly, whereby in addition to a further analog-digital converter 21, a further image memory is provided so that by polling three frame memories on the monitor 23 a natural color image optionally to the mathematically linked image displayed is. This has the particular advantage that the treating physician independently from the constructed diagnostic result and a natural image of the to diagnosed tissue site, so the irradiated of the diagnosis lasers can make diagnostic field.