Laser-applied markings for medical devices for improved sonographic and radiological imaging

Abstract

The invention relates to a method for creating visibility-enhancing markers which can be applied onto a wide variety of materials with a very high degree of geometric variability and which can be used both for radiological as well as for sonographic applications. According to the invention, this is achieved substantially in that the novel markings are created by means of a polyurethane coating into which a particle film with functional properties and high particle density is embedded. By using a laser, only targeted coating regions in selected areas are dried and chemically cross-linked. Exposed areas are created by subsequently rinsing off non-irradiated coating material. The markings can thus be created in any geometric shape.

Description

[0001] Laser-applied markers for improved sonographic and radiological imaging of medical devices

[0002] The invention relates to a method for producing medical devices with markings that are visible for imaging processes. It also relates to medical devices that can be produced using the method.

[0003] The in vitro visibility of medical instruments and implants for therapeutic and diagnostic purposes using ultrasound (US) and X-ray techniques is of high clinical relevance.

[0004] For optimal placement close to the desired site of action and to avoid complications, medical devices should be clearly visible in their entirety during installation until the final position is checked.

[0005] Radiological and sonographic techniques are primarily used to visualize internal patient structures and / or objects within a patient.

[0006] In particular, the present invention relates to catheters. Catheters are typically used for drainage, irrigation, application of diagnostic or therapeutic medications, biopsy, or for establishing passage within hollow organs, and various other procedures. Such catheters predominantly have a base body made of a polymeric material.

[0007] However, because the plastic materials used have very poor ultrasound (echogenicity) and radiographic (X-ray contrast) visibility, the placement and monitoring of an invasive catheter proves difficult. Currently available catheters can only be reliably visualized by ultrasound at depths of a few millimeters below the skin surface.

[0008] The difference in material constants (acoustic impedance and X-ray absorption) between body tissue on the one hand and catheter on the other hand and the geometric dimensions of the catheter are limiting factors for identification.

[0009] The invention includes a method for producing visibility-enhancing markers which can be applied to a wide variety of materials with very high geometric variability and can be used for both radiological and sonographic applications.

[0010] To determine the position of a catheter within a patient along its entire length using X-ray diagnostics, the catheter material is filled, either entirely or in strips, with radiopaque substances such as barium sulfate. Radiopaque markers are often used to identify individual areas of a catheter, such as the distal end.

[0011] It is known to implement markers in the form of a coating, a band, or an inlay. For example, rings made of solid, radiopaque metal are attached to the catheter tube. Since the solid metal band is relatively inflexible compared to the catheter shaft material, local stiffening and unwanted discontinuities arise in the catheter. Bending and / or torsional stress can lead to failure of the composite material, resulting in the loss of the marker. Furthermore, metallic markers are relatively expensive to manufacture and difficult to securely attach to an underlying device.

[0012] Many of the problems associated with the use of metallic markers are overcome by replacing the rigid precious metal tube with a polymer filled or doped with a suitable radiopaque material.

[0013] As described in US 6540 721 and WO 2005 / 030284, such markers are manufactured by mixing a polymer resin with a powdered, radiographically dense material such as elemental tungsten and then extruding the composition. Due to the process and the large density differences between the metal and the polymer, only small volume fractions of the metal can be incorporated into the compound. To achieve sufficient radiographic contrast, excessively thick walls are therefore required. When the markers are attached to the instrument, protrusions are created and the profile is changed in an undesirable way. In many cases, external dimensional restrictions prevent the use of devices with such markings.

[0014] The same applies to the method described in applications DE 10020 739 and WO 2021 / 029348, in which the position and deformation of a surgical instrument can be more accurately identified using coiled, high-contrast tubes or wires. The design flexibility for geometric X-ray image patterns that can be generated using these methods is still very limited.

[0015] Other methods must be used for ultrasonically visible instruments and markings. These approaches are primarily based on the principle that gaseous substances exhibit a significant difference in acoustic impedance compared to solids and human tissue. Exploiting the high impedance jump at the gas / solid interface, substrates or coatings are often proposed that feature, for example, gas pockets, cavities, pores, gas-containing channels, or microscopic surface structures for retaining surface air inclusions. WO 98 / 18387 discloses medical instruments, such as needles, where part of the surface is covered with a material such as epoxy resin filled with reactive substances as bubble-generating agents.Upon contact with a liquid, which can occur during insertion into tissue, substances such as sodium bicarbonate and citric acid react, releasing gas and forming numerous mobile bubbles. Open-pore structures result in rough surfaces and can only provide the desired contrast for a short time, as the gas bubbles gradually dissipate and the surface is moistened with liquid.

[0016] Closed pore structures with defined cell geometry and high homogeneity can be realized as syntactic foams by embedding hollow spheres. DE 20 2009 001 974 U1 discloses full-surface paint coatings with cavities, which are produced by embedding hollow microspheres made of vinylidene chloride, which in turn can be filled with a gas such as isobutane.

[0017] Furthermore, catheters are known which are characterized by a multi-layer structure produced by extrusion. The echogenic properties can be improved by modifying individual layers. EP 1 462 056 relates to a catheter which consists of at least two layers, of which the outer layer is thicker than the inner and gas bubbles are dispersed in the outer layer. Layers produced in this way have the disadvantage that they are present along the entire length of the extruded part and thus also in areas where they are rather undesirable. The production of patterned markings for a better differentiation of the body's own structures and of process-related noise in the ultrasound image is not possible. The physical properties of the device are significantly influenced. For example, the property of transparency, which is often important for catheters, is lost.

[0018] The solution proposed in EP 3738 543, consisting of a multilayer catheter design and laser-induced foaming of the area to be marked, offers extensive possibilities for the graphic design of echogenic markings, but relies on specially designed catheter shafts that are extruded in multiple layers and filled with laser absorbers. Equipping conventional catheter tubes with such echogenic markings is not possible.

[0019] US 2014 / 0221828 A1 discloses medical devices with checkerboard-like echogenic patterns created by casting or printing a metal film or by gas-filled plastic structures. The laser treatment recommended for plastic structuring, in the form presented, has the disadvantage that ablation and bubble formation create depressions and elevations on the surface. It is known that the material changes induced by laser beams are particularly effective in the area near the surface and decrease with increasing layer depth. No solution is presented for limiting the effect of the laser beam to the interior of the catheter wall and avoiding the formation of surface irregularities.

[0020] The object of the invention is to create visibility-enhancing markings on medical devices, in particular catheters, which can be used in both radiological and sonographic imaging and can be precisely and easily placed at any desired location with very high geometric variability. The instruments should retain their transparency and be provided with visible markings only in those areas that are of interest for detectability and possible subsequent manipulation. By designing the markings in the form of graphics, scales, and patterns, the detection of displacements, twisting, kinking, shrinking, or expansion of the device, as well as the identification of functional areas, should be improved.

[0021] Furthermore, a method is to be provided which enables the simple and economical production of markings on medical devices.

[0022] To achieve the object, the invention essentially provides that the novel markings are produced by a polyurethane coating in which a particle film with functional properties is embedded with a high coverage density.

[0023] By using a laser, only specific, location-selective areas of the coating are dried and chemically cross-linked. The markings are then exposed by subsequently rinsing off any unexposed coating material. The markings can thus be executed in any geometric shape.

[0024] The selection of particles depends on the desired functionality. For example, hollow glass microspheres are used for sonographic applications, and spherical tantalum particles are used for X-ray visibility.

[0025] By applying an additional particle-free layer as a coating (5), optimal particle adhesion and surface smoothness can be achieved. Polyurethane systems are preferably used for the coatings. Polyurethanes are formed by the polyaddition of bi- or higher-functional alkanols and isocyanates. They are widely available and can be applied very efficiently to many substrates, such as metals, textiles, ceramics, and heat-sensitive plastics. The preferred application is the marking of medical devices made of plastic. Coating systems with a modular structure are available on the market for this purpose, allowing high flexibility in formulation and application properties. In many cases, polyurethanes also ensure good biocompatibility, thus enabling their use for medical purposes.

[0026] Solvent-based systems or aqueous dispersions and emulsions are used. Water-based compositions offer improved biocompatibility and stability and are more environmentally friendly. The absence of organic solvents often also results in better compatibility with the substrate. Catalysts known from polyurethane chemistry can be used to accelerate the polymerization reaction. Generally, the amount of catalyst required is very small, on the order of 100 ppm or less. Synthesis without a catalyst is preferred.

[0027] Particularly advantageous is the use of so-called curing systems, which chemically react and cure only under increased heat. The temperature ranges between 100 and 200 °C. The time required for sufficient crosslinking is between 2 and 100 minutes and can be shortened by using higher temperatures.

[0028] The polyurethane layers are applied to well-cleaned and possibly activated substrates using conventional methods such as printing, spraying, knife coating, and dipping. Through targeted dilution or the use of thickeners, layer thicknesses in the range of 500 nm to several hundred μm can be achieved, with 5 to 50 μm being preferred within the scope of the present invention.

[0029] Alternatively, other known coatings are also suitable, which can be dried and cured by heat or UV rays and which exhibit biocompatible, non-toxic, hypoallergenic and stable behavior for medical use.

[0030] According to the invention, such a coating can also be selected from the group of sol-gel systems, acrylates, melamine, polyester.

[0031] The tackiness of the coating compound immediately after application is exploited to adhere functional particles. The coated part is sprayed with particles or immersed in a static or fluidized powder, so that the particles adhere to the coating as a film. A film is defined here as a nearly surface-covering single layer of particles whose average height is only slightly larger than the average size of the particles.

[0032] A vortex tank is preferably used for this purpose, with air introduced from below through tiny openings, which swirl the powder and allow it to circulate freely. For a thin layer with a high particle density on the polyurethane layer, finer and spherical geometries prove advantageous.

[0033] The resulting coating structure is then dried and cured by laser-induced heat input. A computer-controlled optical system allows rapidly deflectable laser pulses with the desired power to be applied precisely to the areas to be heated. The heat input is thermally and geometrically precisely defined. The programmed movement of the laser beam allows both relatively large imaging areas and small-area inscriptions, patterns, markings, and the like to be cured with high precision. The resulting marking can be formed as a single piece or comprise several components that can be connected to one another. Rotating devices also allow circumferential markings.

[0034] For this purpose, especially for use on plastic devices, cost-effective diode-pumped solid-state lasers and fiber lasers in the 1064 nm (NIR) wavelength range are preferred, similar to those used for marking and labeling. The shape of the marking is programmed using labeling software.

[0035] Furthermore, the use of an excimer laser, e.g., using a mask technique, is also possible. However, the desired results can also be achieved with other conventional laser types that have a wavelength in a range of high absorption of the absorber materials used, such as CO2 and other dye lasers. The power of the lasers used and the setting of various laser parameters depend on the specific application and can be easily determined by a person skilled in the art in each individual case.

[0036] In metallic devices, the laser energy is absorbed by the substrate, so that the coating compound is heated indirectly. However, unfilled catheter plastics such as TPU, PVC, and silicone, as well as the polyurethane coating itself, are laser-transmissive at wavelengths from near ultraviolet to near infrared light, meaning they do not interact with the laser radiation. It has been shown that metallic particles, which are actually applied to the coating for the purpose of X-ray contrast, can also provide very good laser absorption and thus heat input into the coating. With the help of the adhering metallic particles, it is possible to cure the polyurethane reaction mixture by laser treatment without the need for additional laser additives, even on laser-transparent, heat-sensitive materials.The special heat transfer from the solid particles to the polyurethane layer creates a very strong bond between the particles at the contact points. To ensure the necessary reaction time, the laser beam is repeatedly passed over the surface to be treated.

[0037] The actual exposure of the markings is achieved by rinsing off the non-irradiated and therefore non-crosslinked coating compound. The choice of rinsing fluid depends on the applied coating system and the substrate. For aqueous composites, water is preferred for rinsing. If organic solvents are necessary, any dissolving effect on the substrate and the crosslinked coating must be excluded. Suitable solvents can be ketones such as acetone, butanone, methyl ethyl ketone, methyl isobutyl ketone; cyclic or aromatic hydrocarbons such as xylene, toluene, cyclohexane; or esters such as butyl acetate, ethyl acetate, methoxypropyl acetate; or mixtures of these substances.

[0038] To further increase the reliability of particle adhesion and reduce surface roughness, an additional layer of polyurethane can be applied, which is cured conventionally or by laser treatment. This also provides insulation that prevents unwanted electrochemical processes in the blood or other body fluids between the metal particles and the instrument. Furthermore, it has proven advantageous to subject the medical device with the applied markings to a heat treatment in an oven, which ensures complete curing of the polyurethane coating and complete evaporation of the solvent.

[0039] The required functionality of the markings according to the invention is ensured by the embedded particles. Radiopaque powder materials suitable for imaging in X-ray diagnostics include metallurgical materials with high atomic numbers such as platinum, tantalum, iridium, tungsten, rhenium, gold, and alloys of these metals. Metal compounds such as tungsten carbide, tungsten boride, barium sulfate, and bismuth chloride oxide can also be used to produce markings on metallic devices.

[0040] The shape of the particles is not critical, but should preferably be spherical. Suitable particle sizes range from 1 to 50 μm, with diameters of 5 to 10 μm being particularly preferred. Smaller particles produce a thinner coating that has less impact on the properties of the medical device. For non-spherical particles, the size specifications refer to the equivalent sphere diameter, i.e., the diameter of a sphere with the same volume as the particle.

[0041] One of the key advantages of the method according to the invention is that the particles are embedded in a very high proportion of the total volume of the coating. The functional volume fraction can be 40–75% and is preferably achieved in the range of 50–70%. For the ultrasonic visibility function, hollow micro-bodies can be embedded in the marking composite according to the state of the art. Hollow glass and ceramic spheres, as well as polymeric microspheres, are particularly suitable.

[0042] Alternatively, expandable microspheres are used. These particles are microscopically small spheres with a thermoplastic outer shell and a condensed gas filling that expand upon heating. In addition to the use of already expanded hollow spheres, it is possible to expand non-expanded types during laser treatment. This allows the proportion of functional volume in the coating to be further increased.

[0043] Compared to rigid hollow spheres, polymeric elastic microbubbles can enable better ultrasound visibility. Not only do they offer a drastically different acoustic impedance than human tissue, but they also act as resonators for ultrasound waves, thus increasing the backscattering effect.

[0044] Preferably, echogenic microparticles with a diameter between 1 and 50 μm are used.

[0045] However, due to the very low laser absorption of the hollow micro-bodies, their use in the process according to the invention is limited to devices with metallic materials. Surprisingly, it has been shown that a coating structure with embedded metal particles also produces very good echogenic behavior. It can be assumed that, due to the process, cavities arise in the coating composite that are not completely filled with polymer even by the final applied top layer. The second polyurethane layer results in a closed-pore structure, so that the cavities are retained even upon contact with body and other fluids. The gas inclusions in the coatings cause a strong reflection of the sound waves, so that they appear significantly brighter in the ultrasound image compared to the surrounding substances.

[0046] Using this method, markings can be created on metallic and non-metallic devices that enable improved image representation with both radiological and sonographic diagnostic procedures. The studies on the examples presented show that, despite the bifunctional effect of the markings, high-quality images with perfect contrast and high detail fidelity can be achieved with both methods. The markings are characterized by high smudge and scratch resistance and are stable during subsequent sterilization processes.

[0047] The claimed method is therefore particularly suitable for marking catheters, where few technical solutions to improve detectability have been available so far. The preferred patterned design of the markings enables easy differentiation from endogenous structures and allows for the easy detection of displacements, kinks, or twists. Furthermore, the pattern offers the possibility of scaling areas of particular interest and highlighting them for subsequent manipulation of the catheter.

[0048] In addition to its use on catheters, the method can also be implemented on other medical devices that are introduced or implanted into an animal or human body. A medical device according to the present invention is therefore preferably selected from the group consisting of catheters, needles, stents, cannulas, tracheotomes, endoscopes, dilators, tubes, introducers, markers, stylets, snares, angioplasty devices, fiducials, trocars, and forceps.

[0049] The invention is explained below using an exemplary embodiment. Further details, advantages, and features of the invention emerge directly from the claims.

[0050] The drawings show in

[0051] Fig. 1 is a schematic representation of markings on a catheter produced according to Example 1,

[0052] Fig. 2 is a photograph of a catheter equipped with markers according to Example 1,

[0053] Fig. 3 Ultrasound images of the markers produced according to Examples 1 and 2

[0054] (a) measured on a catheter and in water

[0055] (b) measured on a cannula and on an ultrasound phantom

[0056] Fig. 4 is an X-ray image of a catheter manufactured according to Example 1.

[0057] Fig. 1 shows various views of the basic structure of a catheter 01 provided with markings 03, 04. The catheter is designed, for example, with three ring-shaped markings 03 arranged around the circumference with different widths, as well as with three markings connecting the rings as longitudinally arranged webs 04.

[0058] The markings lie on the catheter wall 02 and are characterized by a structure in which a film of closely spaced metal particles 07 is embedded between two polyurethane layers 05, 06. The spaces between the particles are not completely filled with polymer, so that air-containing cavities 08 are present. The cavities are closed to the outside by the cover layer 06. The radiopaque, spherical metal particles 07 have an average size of 10 μm and account for 50-70% of the volume of the marking. The total thickness of the coating, at approximately 15 μm, is only slightly larger than the diameter of the individual particles.

[0059] The markings shown in Fig. 2 were made on a TPU catheter with an outer diameter of 3 mm and have the structure shown in Fig. 1.

[0060] Markings produced according to the invention stand out in X-ray (Fig. 3) and ultrasound images (Fig. 4) with very high brightness contrasts and good contour sharpness from the black background and from the untreated areas of the instruments.

[0061] The following examples serve to illustrate the invention. Percentages are by weight unless otherwise stated or apparent from the context.

[0062] Materials used

[0063] Unless otherwise stated, all materials were purchased from CSC JÄKLECHEMIE GmbH & Co. KG.

[0064] Elastollan® 1180 A10 FC is a TPU from BASF, which has a Shore A hardness of 80, a strength of 45 MPa and an elongation at break of 650%.

[0065] Desmophen® T1777 is a polyol component for the production of polyurethane baking finishes with blocked aliphatic polyisocyanates from Covestro. Desmodur® BL 3475 is a diethyl malonate-blocked, aliphatic polyisocyanate based on isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI) from Covestro.

[0066] Bayhytherm® 3246 is a water-dilutable, aliphatic, self-crosslinking stoving urethane resin from Covestro.

[0067] Methods

[0068] Ultrasound visibility tests were performed in B-mode using a Mindray DP-50 ultrasound diagnostic device and a linear transducer at a sound frequency of 8 MHz. For the ultrasound images, the various devices were positioned at a 45° angle to the sound direction in both a water bath and an ultrasound phantom with tissue-like properties. To evaluate the contrast of the marking compared to unmarked areas, the grayscale spectra (histograms) of the individual areas of the ultrasound image were averaged and compared using image processing software, with 100% black corresponding to a value of 0 and 100% white to a value of 255.

[0069] The X-ray images were examined using an intraoral X-ray system from Trophy-Radiologie GmbH with digital sensor technology. An aluminum strip with graduated thicknesses of 1, 2, 3, and 4 mm was used as a reference standard. The exposure setting of the X-ray machine was selected so that the four levels were imaged with high contrast differences (70 kV, 10 mA, 0.5 seconds, sensor size 18 x 24 cm). Example 1

[0070] This example describes the production of a marker according to the invention on a catheter.

[0071] A catheter with an outer diameter of 3 mm and a layer thickness of 0.5 mm is manufactured using a tubing extrusion system. The tubing material is a TPU of the type Elastollan® 1180 A10 FC.

[0072] A coating compound is prepared by placing the following ingredients in a beaker and mixing them together. Desmophen® T1777: 34.8%

[0073] Desmodur® BL 3475: 27.9%

[0074] 1-Methoxy-2-propyl acetate: 37.2%.

[0075] The catheter is plugged at one end, immersed in the coating solution, and then withdrawn very slowly at a speed of 1 mm / s. The excess solution is allowed to drain, and the coated tube is dried for 2 minutes at room temperature.

[0076] Tantalum powder with an average particle size of 8 μm is fluidized in a fluid basin using compressed air. The catheter is immersed in the fluidized bed while rotating and remains there until sufficient particles adhere to the sticky coating. After a further drying time of 10 minutes, the tube is irradiated with a pulsed 10-watt Yb fiber laser from FOBA. By selecting suitable laser parameters (laser power: 20%, travel speed: 10 mm / s, pulse frequency: 20 kHz), a temperature increase is caused at the irradiated areas 03 and 04, which leads to crosslinking and curing of the coating. The movement of the laser beam to form the contour and fill the areas is repeated several times so that the local temperature increase is maintained over a period of 20 minutes.

[0077] The circumferential ring markings 03 were programmed as rectangles using the laser marking software and created by axially rotating the tube during laser treatment. The ridges 04 were created on the stationary tube by repeated lasering after each 120° rotation of the tube. After laser treatment, the coated part of the catheter is immersed in 1-methoxy-2-propyl acetate, and the uncured coating compound is rinsed off by movement.

[0078] After a drying time of 10 minutes, the process of dip coating, laser treatment, and rinsing is repeated to form the top layer. The application of particles is omitted in this step. The result is a marking as shown in Fig. 2.

[0079] Fig. 3a shows the ultrasound images of catheter 01 immersed in water at a 45° angle to the transmitted ultrasound. The image of the marked catheter in an X-ray image is shown in Fig. 4. To allow comparison with current practice, a standard (aluminum plate with thickness gradations of 1, 2, 3, and 4 mm) was included with the image.

[0080] The following tables provide an overview of the average brightness values ​​of the various image areas determined from a gray value histogram.

[0081] Both subjective visual observation and digital analysis of the images demonstrate the high functionality of the imaging markers. The marker exhibits very good radiopacity, approximately equivalent to a 2 mm thick aluminum plate.

[0082] Example 2

[0083] This example describes the production of a marking according to the invention on a 22G disposable cannula (outer diameter: 0.7 mm) made of stainless chromium-nickel steel.

[0084] In contrast to example 1, the coating mass is prepared from the following components.

[0085] Bayhytherm® 3246: 90%

[0086] Distilled water: 10%.

[0087] The particles used are hollow glass microspheres of the type 3M™ Glass Bubbles K37 with an average particle size of 40 μm. The marking is formed in the form of three circumferential rings with a width of 3 mm. The sonographic examinations were performed on a commercial ultrasound phantom made of tissue-mimicking material. Fig. 3b shows an ultrasound image of the 0.7 mm thin needle at an ultrasound frequency of 8 MHz at a depth of 1 to 2 cm.

[0088] The following table provides an overview of the mean brightness values ​​of the various image areas in the ultrasound image calculated from a gray value histogram (Fig. 3b).

[0089] Despite the small diameter of the needles, the markings are characterized by very good ultrasound visibility.

[0090] List of reference symbols:

[0091] 01 - Catheter

[0092] 02 - Catheter wall

[0093] 03 - Ring marking

[0094] 04 - Bridge marking

[0095] 05 - PU base layer

[0096] 06 - PU top layer

[0097] 07 - Particle film

Claims

Patent claims:

1. A method for manufacturing a medical device with markings visible for imaging procedures, characterized by the following steps: a. Applying a thin layer of a liquid, thermally curable polyurethane system to the device to be marked; b. Adhering a film of microhollow spheres or metal particles to the polyurethane coating applied in step a); c. Curing the coating mass at defined locations by means of a laser in the form of patterns, such that only a portion of the coating mass cures; d. Rinsing off uncrosslinked coating mass with a suitable solvent; and e. Applying and curing a topcoat.

2. Method according to claim 1, characterized in that the metal particles are 1 to 50 μm, preferably 1 to 10 μm, in size.

3. A method according to claim 1 or 2, characterized in that the metal particles have a density greater than 4 g / cm³ 3 have and consist predominantly of metals with an atomic number greater than 21, with platinum, tantalum, iridium, tungsten, rhenium, gold and alloys of these metals being preferred, but metal compounds such as tungsten carbide, tungsten boride, barium sulfate, bismuth chloride oxide are also suitable.

4. Method according to claim 1, characterized in that the microhollow spheres have a particle size of 10 to 80 μm, preferably 30 to 50 μm.

5. The method of claim 1, characterized in that the microhollow spheres are used in the form of glass and ceramic hollow spheres as well as polymer microspheres.

6. The method of one or more of claims 1 to 10. 5, characterized in that the volume fraction of particles in the coating is 40 to 75%, preferably 50 to 70%.

7. Method according to one or more of claims 1 to 6, characterized in that the markings can be applied in the form of characters, shapes, graphics, scales or patterns.

8. Method according to one or more of claims 1 to 8. 7, characterized in that the particle film is applied by immersion in a fluidizing tank with fluidizing powder, or by spraying or doctor blade application.

9. Method according to one or more of claims 1 to 8, characterized in that the curing of the coating is effected by irradiation with laser light whose wavelength lies in the near-UV and / or visible and / or near-IR range.

10. Medical device with marking for imaging procedures, characterized in that it is produced according to a method according to one or more of claims 1 to 9 is manufactured.

11. Medical device according to claim 10, characterized in that it comprises catheters, needles, stents, cannulas, tracheotomes, endoscopes, dilators, tubes, introducers, markers, stylets, loops, angioplasty devices, trocars or forceps.

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