Irradiation device for photodynamic therapy

Abstract

The invention relates to an irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) for photodynamic therapy, comprising a proximal portion (16) and a rod-like light-emitting portion (22, 35) which is arranged distally from the proximal portion (16) and is intended to be introduced into a hollow organ (5, 30), wherein: the light-emitting portion (22, 35) comprises a distal end (17), a lateral surface (33, 71, 81, 403, 503, 504, 722, 723), at least one electrically operable lamp (37), at least one electric line (78) and at least one cooling channel (70, 703, 704, 706, 707); the at least one lamp (37) is distributed on or radially on the inside of the lateral surface (33, 71, 81, 403, 503, 504, 722, 723) in order to emit light from the lateral surface (33, 71, 81, 403, 503, 504, 722, 723) in a plurality of spatial directions; the at least one lamp (37) is connected to the at least one electric line (78) that runs to the proximal portion (16) of the irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15); and the at least one cooling channel (70, 703, 704, 706, 707) is arranged in the light-emitting portion (22, 35) and passes, at least in part, the at least one lamp (37) and is designed to conduct fluid for absorbing heat from the lamp (37) in question.

Description

Title: Irradiation device for photodynamic therapy therapy Description

[0001] The invention relates to an irradiation device for photodynamic therapy (PDT) with the features specified in the preamble of claim 1, in particular for PDT of the inner surfaces of a hollow organ.

[0002] In photodynamic therapy, altered tissue is treated with light and a light-active substance in combination with oxygen present in the tissue. The substance accumulates largely selectively in tissue alterations and, upon subsequent irradiation with light of a suitable wavelength, causes selective damage only to the pathological tissue. When treating tumors on endoscopically accessible, internal body surfaces, it is advantageous to perform large-area, preferably complete and non-point-specific irradiation, or at least to irradiate larger sections of the interior of a hollow organ simultaneously. This can include, for example, longer entire sections of the hollow organ or the entire hollow organ, such as the esophagus, bladder, trachea, colon, rectum, etc.This approach not only targets endoscopically visible pathological tissue areas with radiation, but also treats at least nearly all endoscopically accessible tissue areas inside the hollow organ. Pathological tissue that is difficult or impossible to visualize endoscopically is therefore reliably detected and treated through this near-complete irradiation. By using light to illuminate the surface of the affected hollow organ, treatment time and effort can be minimized. Furthermore, this ensures that areas of pathological tissue within the hollow organ that are difficult or impossible to see do not go untreated.

[0003] For effective treatment, a minimum dose of light irradiation is necessary, meaning a minimum irradiance for a minimum irradiation duration, i.e., a minimum optical power per unit area for a minimum irradiation duration, is required for each tissue segment to be treated. This can depend, among other things, on the photoactive substance and / or the hollow organ or tissue being treated. To keep treatment time and the associated treatment effort as short as possible, the minimum optical power per unit area should be as high as possible. Consequently, larger surfaces to be treated require correspondingly larger amounts of light. Irradiation should also be largely homogeneous to ensure that all relevant tissue areas are irradiated with a minimum dose and that as few tissue areas as possible remain untreated.

[0004] One challenge in performing photodynamic therapy lies in the limited size of the access to the interior of the hollow organ, both with natural access routes, such as access to the bladder via the urethra or to the stomach via the esophagus, and with access routes created artificially for therapy, such as through a targeted incision and / or the insertion of a trocar. If a light source is located outside the hollow organ being treated, a sufficiently sized optical fiber is necessary for insertion into the interior of the hollow organ, as well as a suitable diffuser positioned inside the hollow organ to distribute the light flux. It is also known to use a point light source at a distal The diffuser or point light source can be positioned at the end of an applicator. In the case of large-lumen hollow organs, the diffuser or point light source can be located at correspondingly large distances from the surface to be treated, with the irradiance at the tissue being inversely proportional to the square of the distance between the light source and the tissue. Consequently, considerable amounts of light may be necessary at greater distances to ensure a minimum irradiance. However, this can lead to considerable heat generation at the light source.

[0005] For example, EP 2 382 009 Bl discloses an irradiation device for insertion into a body opening to provide photodynamic therapy. The device comprises a housing designed to be inserted into and secured within the opening, and the housing incorporates an LED lamp system designed to emit radiation from a treatment surface. However, the irradiation device is intended for specific organs where the treatment surface can be positioned very close to the tissue being treated. A sufficient number of light sources at a short distance from the tissue, with a comparatively low amount of light emitted per light source, results in the desired local illuminance at the tissue with minimal heat generation at the light sources.

[0006] Against this background, the invention is based on the objective of providing an alternative irradiation device for photodynamic therapy, wherein the irradiation device enables large-area, homogeneous irradiation of internal surfaces of a hollow organ with sufficient illuminance, causes the lowest possible heat load, particularly at the light source, and can be inserted into the hollow organ through narrow natural or artificial access points.

[0007] This objective is achieved according to the invention by an irradiation device having the features specified in claim 1. Advantageous embodiments of the invention are described in the dependent claims, the following description, and the drawings.

[0008] The irradiation device according to the invention for photodynamic therapy has a proximal section and a rod-shaped light emission section arranged distal to the proximal section for insertion into a hollow organ, wherein the light emission section has a distal end, a cladding surface, at least one electrically operable light source, at least one electrical conductor, and at least one cooling channel, wherein the light sources are distributed on or radially inside the cladding surface in order to jointly emit light from the cladding surface in several spatial directions, wherein the at least one light source is connected to the at least one electrical conductor that runs to the proximal section of the irradiation device, and wherein the at least one cooling channel is arranged in the light emission section and leads past the at least one light source at least sectionally and is configured toto conduct a fluid to absorb heat from the light sources in question.

[0009] Optionally, the at least one light source may comprise at least one electrically operated light source extending over the entire light emission area and / or a plurality of light sources distributed over the light emission area. For example, the at least one light source may comprise at least one organic LED (OLED) extending over an entire area and / or an arrangement of a plurality of inorganic LEDs.

[0010] The irradiation device according to the invention is therefore designed to generate the light required for photodynamic therapy in the region of the distal end. For this purpose, at least one light source is provided, which is supplied with electrical energy via at least one electrical conductor. It is understandable that the at least one electrical conductor can be connected proximally to an electrical supply unit arranged outside the rod-shaped light emission section in order to supply the light source with suitable electrical energy via the at least one electrical conductor.

[0011] The at least one light source is arranged in the region of the distal end. Instead of a single, point-like light source, a more diffuse light distribution is provided. Instead of a single diffuse light source, several light sources can be used, distributed accordingly on or radially inside the outer surface. The outer surface is understood to be an area of ​​the light-emitting section that surrounds a principal axis of the light-emitting section. Preferably, a plurality of light sources are distributed on the outer surface in a specific grid or at specific intervals. Such a grid or the spacing of the light sources can be adapted to the geometry of the hollow organ to be irradiated and to the expected distance between the surface of the hollow organ to be irradiated and the outer surface.For example, in areas where a large distance between the area to be illuminated and the surface of the housing is expected, the light sources can be closer together, i.e., more densely distributed on the surface of the housing. Conversely, in areas where a smaller distance between the area to be illuminated and the surface of the housing is expected, the light sources can be further apart, i.e., less densely distributed on the surface of the housing. Alternatively. In addition, the light sources can be evenly distributed across the surface of the device, but may be supplied with varying currents. The power supply unit of the irradiation device can be adjusted accordingly, or it can be pre-programmed or pre-programmable for specific organs. Light sources located at a greater expected distance from the area to be irradiated can be supplied with a higher current and thus emit more light, whereas light sources located at a shorter expected distance can be supplied with a lower current and thus emit less light. Light is preferably emitted in all radial directions around the main axis of extension, and, if required, homogeneously over the largest possible solid angle. The surface of the device does not necessarily have to be the outermost surface of the light-emitting section.Rather, it is also conceivable that the cladding surface is surrounded by a transparent protective layer, is an inner cladding surface, or is an inner or outer cladding surface of a component that is surrounded by other components.

[0012] The at least one light source is preferably one or more LEDs. These LEDs are particularly preferably designed such that their emission spectrum exhibits a particularly strong overlap with the absorption spectrum of a photoactive substance used. The LEDs can be implemented, for example, as a plurality of inorganic LEDs and / or as at least one planar organic LED, so-called OLED. The LEDs can be mounted as separate components on a conductor track. It is also conceivable that the LEDs, as micro-LEDs, are either mounted directly onto the surface of the device or first onto a thin-walled tube, which is then attached to the surface. These micro-LEDs consist of a multitude of tiny LEDs. Inorganic LEDs are embedded between thin conductive layers, at least one of which is transparent, resulting in a particularly thin light source and making the microLEDs, like a planar OLED, a light-emitting device that, overall, emits light across a flat surface. Furthermore, the OLED or the microLEDs, or their flexible conductive traces, can be printed directly onto the surface of the light-emitting section.

[0013] The at least one cooling channel is provided to cool the at least one light source. For this purpose, a fluid is circulated through the at least one cooling channel. The cooling channel is arranged so that the fluid flows along the light source, thereby enabling the best possible heat absorption by the light source. The thermal resistance between the light source and the fluid should be as low as possible. This could also be achieved by having the at least one cooling channel run directly past the light source or at the smallest possible distance.

[0014] When the interior of a hollow organ being treated is irradiated with light over a large area, comparatively large amounts of light are required, which must be supplied by the light source. This is particularly pronounced when the internal lumen of the hollow organ being treated is quite large, but access to its interior is quite narrow, as is the case, for example, with the bladder and the urethra as its natural access point. In such cases, the distance between the affected tissue and the light source could be considerable, further increasing the total amount of light required to achieve the necessary minimum irradiance even in the most distant tissue areas. Providing large amounts of light requires high electrical power consumption. This, in turn, results in correspondingly high electrical power loss, which is released by the irradiation device as heat.

[0015] The heat is efficiently dissipated by at least one cooling channel, preventing excessively high temperatures at the light source itself and thus reducing the resulting loss of optical performance. Especially when the light source is designed as one or more LEDs, it is important to note that the temperature increase of an LED relative to its surroundings is proportional to both the LED's electrical power consumption and the thermal resistance between the LED and its environment. Using multiple LEDs initially distributes the total light output across several LEDs or, in the case of OLEDs or micro-LEDs, over a larger area, thus requiring less electrical power locally. However, this measure is limited because the surface area from which the light is emitted is also spatially restricted.Increasing the surface area of ​​the casing to accommodate a large number of light sources is hardly feasible, as the rod-shaped light-emitting section must be inserted into the hollow organ from the outside through a natural or artificial opening, thus limiting its size. Furthermore, the complexity, manufacturing effort, and therefore production costs increase with the number of light sources. The direct component costs also rise. Since it makes sense to design the rod-shaped light-emitting section as a disposable item for easy disposal after a single treatment procedure, it should be as inexpensive and simple to design as possible.

[0016] The thermal stress on the at least one light source is reduced by the at least one cooling channel. The light source is cooled by targeted forced convection. Consequently, with increasing cooling, increasing electrical power can be drawn without entering a critical temperature range and thus risking power losses or failures. This is particularly advantageous when the light source is one or more LEDs. Furthermore, the optical output of the entire assembly can be easily increased by raising the potential power consumption of each light source. No further measures, such as modifications to the geometry or materials used for the rod-shaped light emission section, are necessary, thus avoiding any additional costs in this regard. Within certain limits, the controlled, forced convection allows for an arbitrary increase in the optical output of the light source simply by increasing the flow rate of the circulating fluid. This could be achieved by increasing the output of a pump connected to the at least one cooling channel, increasing the outlet height of a bag or canister containing the fluid, or increasing the pressure of a gaseous fluid at a valve of a pressure vessel.

[0017] The procedure described above allows the cooling capacity and, consequently, the optical performance of the irradiation device to be easily scalable within certain limits, without requiring changes to the geometry or materials of the rod-shaped light emission section, nor to the number or size of the light sources. The basic design of the device can therefore be used unchanged for various applications with correspondingly different light output requirements. This enables the creation of a simple and cost-effective basic version of the irradiation device that can be used universally with little or no modification. Furthermore, this allows for cost-effective mass production.

[0018] The concept of the device according to the invention also has the advantage that a device that is already in use for other reasons is already in use.A flowing fluid, in the form of a liquid or a gas, can be used to implement the cooling function. For example, this could be a fluid for rinsing the interior of a hollow organ. A rinsing fluid then also acts as a cooling fluid through the at least one cooling channel of the device according to the invention. Furthermore, the convection current can be used not only to cool the at least one light source but also to cool tissue. For example, continuous irrigation, such as with saline solution, could be performed in the bladder during photodynamic therapy to keep the interior of the bladder clean of blood and suspended particles from the urine, which is released into the bladder from the kidneys via the ureters during treatment. This prevents an undesirable and, above all, uncontrolled attenuation of the light, which could lead to an undefined therapeutic outcome.The rinsing fluid can be required or used in the bladder during application to achieve complete bladder expansion. The fluid, which is necessary for various reasons in this application anyway, can therefore also be used specifically as a cooling fluid for the light source(s) in the device according to the invention.

[0019] The light-emitting section could be designed to be inserted into a body opening to deliver photodynamic therapy. The outer diameter of the rod-shaped light-emitting section could be approximately 5 mm or less.

[0020] The rod-shaped light emission section could form at least one hollow body, which includes at least one cooling channel. The at least one hollow body has an outer surface that defines a volume occupied by the at least one hollow body. Within this volume is at least one cavity. This cavity could constitute at least part of a cooling channel. As will be explained below, many variations of hollow bodies are conceivable that can be used for the irradiation device according to the invention. Elongated hollow bodies with at least one longitudinally extending cavity are particularly advantageous. The hollow body could form the light emission section itself or at least a part thereof.

[0021] The at least one hollow body could have a radially central cavity. Consequently, the at least one hollow body could be a hollow cylinder. The at least one light source can be arranged radially on the outside, radially on the inside, or within one of the two sections of the hollow body. If the light source is located radially on the inside or within one of the sections of the hollow body, the body must be at least partially transparent. If the light source is located on the outside, it can be surrounded by a transparent protective layer. The cavity can be used for various purposes, which are explained below. In addition to its use in imaging devices, the cavity could also be used for mounting on a rod and / or for guiding a fluid. This can enhance the multifunctional design and reduce the dimensions of the rod-shaped light-emitting section.

[0022] The rod-shaped light emission section could further comprise a rod on which the at least one light source is arranged, wherein the rod is at least partially surrounded by the at least one hollow body, and wherein the at least one hollow body is transparent. The rod provides structural stability, allowing a user to hold the hollow body at the proximal end and move the distal end precisely to the examination site. The rod need not necessarily be rigid, but could, as further explained below, be of a different design. The rod will also exhibit a certain degree of shape variability. The at least one hollow body could be flexible and have a thin wall, since the hollow body does not essentially need to perform any mechanical function contributing to strength. It is preferred if the rod is made at least partially of a metallic material to achieve good thermal conductivity.

[0023] The rod could have radially external, axially extending grooves in which the at least one light source and the at least one electrical conductor are arranged. The grooves can be straight. Several grooves can be spaced apart from each other circumferentially and arranged parallel to one another. Several light sources can be arranged in series within each groove. The electrical conductor supplying the light source could run radially inside the respective groove, while the light source could be arranged radially outside on the respective conductor. The grooves can be distributed symmetrically around the circumference.

[0024] The rod could be hollow and form one of the at least one hollow body. If the rod is also a hollow body, the at least one light source could be arranged on its radial outer surface. The cavity, which could be formed inside the rod and especially in the center of its cross-section, can be used for purposes explained below. If the light source is located on an outer surface of the rod, a transparent protective layer or casing could be provided there, which protects the light source from moisture and dirt while still allowing it to emit light.

[0025] The rod could be rigid. Therefore, manipulating the irradiation device to move the distal end is not possible. It's quite simple. One user can hold a proximal end and use it to guide the distal end.

[0026] Alternatively, the rod could be segmented axially, with at least one of the hollow sections being flexible. The rod would then form several segments arranged along the length of the irradiation device. The individual segments could be connected by the hollow section surrounding the rod. Each segment could be a ring or a disc, with the light source mounted on its radial outer surface. It is also conceivable that elastic connectors could be arranged between the individual segments to provide the rod with some residual rigidity. For this purpose, connecting rings made of an elastic, rubber-like material could be placed between the individual segments. As mentioned above, the segments could also simply be connected by the hollow section.

[0027] The at least one hollow body could comprise a hollow cylinder with an inner shell and an outer shell enclosing the inner shell, with the at least one cooling channel located between the inner shell and the outer shell. The hollow body could therefore be designed as a type of annular channel through which the fluid can flow. The at least one cooling channel is preferably arranged directly on the at least one light source. For this purpose, the hollow cylinder can have radial recesses for receiving the light source or projections for surface contact of the light source.

[0028] To ensure a flow-through cross-section of the at least one cooling channel, the outer shell could be supported, at least partially, by the inner shell. This could be achieved, for example, by ribs or similar features extending radially from the inner shell to the extend outwards towards the outer shell. The ribs can be continuous or form interrupted webs that hold the inner and outer shells at a predetermined distance from each other.

[0029] The at least one hollow body could be a hollow cylinder with an inner and an outer wall, wherein a volume formed between the inner and outer walls comprises a plastic, and wherein several axially extending, parallel recesses, spaced apart circumferentially, are arranged within this volume, forming the at least one cooling channel. This allows for the realization of a highly flexible hollow body comprising several independent cooling channels. Even with significant angulation of the rod-shaped light emission section, these channels can ensure a sufficient volume flow. It is conceivable that some of these cooling channels could be used as a forward flow channel and others as a reverse flow channel.

[0030] The at least one cooling channel could comprise at least one forward and one return flow channel, wherein the at least one cooling channel is closed to the outside. Consequently, the fluid does not leave the irradiation device. The forward flow channel preferably runs directly past the light source, while the return flow channel could be located further away from the light source. For example, the return flow channel could run radially further inward than the forward flow channel, such as in a central cavity arranged in the rod-shaped light emission section.

[0031] The at least one forward flow channel or the at least one return flow channel could be formed by the inner radial section. The forward and return flow channels are therefore separated from each other in the radial direction. By using the inner radial A multifunctional design can be supported for the section for the forward or return flow channel.

[0032] The at least one cooling channel could be open to the outside at an outlet near the distal end of the rod-shaped light emission section, so that the fluid conveyed in the at least one cooling channel exits at this outlet. The irradiation device is then particularly simple in design and has a particularly small radial extent, as the fluid is allowed to enter the inner lumen under investigation. This fluid can be, in particular, a rinsing fluid, for example, a saline solution.

[0033] In an advantageous embodiment, a closed or open viewing window, arranged transversely or obliquely to a longitudinal axis of the rod-shaped light emission section, is located at the distal end, with the inner section of the hollow body being dimensioned to accommodate an imaging device, at least temporarily. The irradiation device can therefore be equipped with an imaging device, allowing the distal end to be easily positioned by a user via the viewing window. It is conceivable that the imaging device can also be removed from the hollow body again if the irradiation device is conveniently positioned. In one embodiment, the imaging device can also include a light guide that can be placed in the inner section of the hollow body and is coupled to an image acquisition unit or the like outside the rod-shaped light emission section.

[0034] Furthermore, the rod could also be spirally shaped. This gives the rod a certain flexibility, allowing it to be angled, for example, to guide it in a specific direction. The spiral shape could be achieved by cutting the rod in a spiral pattern.

[0035] At least one of the light sources could be covered by a transparent, electrically non-conductive protective layer. This protects the light source from moisture and dirt. The material should be biocompatible and could, for example, be silicone or a silicone-like material.

[0036] According to the invention, the light emission section has at least three axial subsections. In an axially central subsection, a plurality of light sources distributed across the light emission section can be arranged more densely than in the axially outer subsections. The relative length and / or arrangement of the subsections to one another can be adapted to the hollow organ to be irradiated. The irradiation device can thus be designed to be organ-specific. The outer surface can therefore be more densely populated with light sources in the central subsection, where the expected distance between the outer surface and the inner surface of the hollow organ to be irradiated is greater, and less densely populated with light sources in the axially outer subsections, where the expected distance between the outer surface and the inner surface of the hollow organ to be irradiated is smaller.This is useful, for example, for an organ-specific design of the irradiation device adapted to a spherical hollow organ such as the bladder. As expected, the central subsection is furthest from the inner surface of a spherical hollow organ. It should be noted that the subsections do not necessarily have sharp boundaries with each other; rather, the luminescent medium density can change gradually and / or in steps between the subsections.

[0037] Alternatively or additionally to an organ-specific arrangement of the light sources, according to the invention, the at least one light source in the axially central subsection can be subjected to a higher electrical current than in the axially outer subsections. The relative length and / or arrangement of the subsections to one another can be adapted to the hollow organ to be irradiated. The irradiation device can therefore be designed with an organ-specific current supply, either alternatively or additionally. Thus, the light source can be subjected to a higher current or operated with a higher electrical energy in the central subsection, where the expected distance between the outer surface and the inner surface of the hollow organ to be irradiated is greater, and can be subjected to a lower current or operated with a lower electrical energy in the axially outer subsections, where the expected distance between the outer surface and the inner surface of the hollow organ to be irradiated is smaller.This is useful, for example, for an organ-specific design of the irradiation device adapted to a spherical hollow organ such as the bladder. The middle subsection is, as expected, furthest from the inner surface of a spherical hollow organ. The power supply unit of the irradiation device can be adjusted accordingly for the current, or the power supply unit can be pre-programmed or pre-programmable for the specific organ. It should be noted that the subsections do not need to define sharp boundaries with each other; rather, the current intensity can change gradually and / or in steps between the subsections.

[0038] The invention is explained in more detail below with reference to the exemplary embodiment shown in the drawings. The drawings show: Fig. 1 shows a prior art irradiation device. Figs. 2a, b and 3 to 1 show different embodiments of the irradiation device according to the invention in schematic representations.

[0039] Fig. 1 schematically shows a setup of an irradiation device according to the prior art. Here, an external or separate light source 1 is provided, which is coupled to a light applicator 2 comprising a light guide 3 and a diffuser 4. The light source 1 can be a narrowband emitting laser or a broadband emitting xenon light source, optionally with upstream optical filters to limit the emission band. The diffuser could be made of a transparent plastic with integrated scattering particles.

[0040] The light used for photodynamic therapy is therefore generated outside of an application site 5 in the form of a hollow organ where the therapy takes place. There, the light enters the diffuser 4 through the light guide 3, initially with a more or less pronounced distal bias, where it is expanded and dispersed. However, the emission pattern of the light emitted distally by the light applicator 2 can only be manipulated to a limited extent with the prior art combination of light guide s and diffuser 4, for example, by adjusting the design of the diffuser 4 without excessively increasing its size. Consequently, the expansion and distribution of the light in the sense of achieving the required large-area and homogeneous irradiation is only partially achievable.If longer sections of tubular hollow organs, such as the colon, bladder, esophagus, or trachea, need to be treated, correspondingly long diffusing bodies that radiate laterally would also be required. These are only feasible with considerable effort and high costs. Furthermore, high power losses result from the limited efficiency of the light guide and the scattering body.

[0041] If organ 5 has a large lumen, the distances between the diffusing body and the inner wall of organ 5 are large. Since the resulting irradiance at the tissue is inversely proportional to the square of the distance between the diffusing body 4 and the inner wall, the power loss of the light applicator 2 is considerable, and homogeneous irradiation of large areas of the inner wall is practically impossible. This is particularly pronounced when the dimensions of the light applicator 2 are severely limited by a narrow natural passage, but the distances between the tissue areas to be irradiated and the diffusing body are large, as is the case, for example, with the irradiation of the bladder mucosa, where a comparatively high light power must be transported through the narrow passage of the urethra.

[0042] Furthermore, aging effects, optical degradation, and wear of the light source 1 and the light guide 3 are to be expected, which can result in high maintenance costs for such an irradiation device. Additional calibration steps would also be necessary before use, potentially leading to reduced reliability and safety. If calibration is not performed or is performed incorrectly, faulty light output could result, potentially preventing the desired therapeutic outcome.

[0043] Fig. 2a shows an irradiation device 6 according to the invention, comprising a power supply unit 20, an electrical transmission unit 21 in a proximal section 16, and distal to it a rod-shaped light emission section 22 extending to a distal end 17. The power supply unit 20 can be a current source which The light emission section 22 provides a preferably stabilized, adjustable current. It is designed for insertion into the hollow organ 5, e.g., the bladder, through an access point 34, which may be, for example, a urethra. The rod-shaped light emission section 22 comprises several light sources 37, which are electrically connected to the power supply unit 20 and arranged distributed on a surface 33, generating light for irradiation directly within the hollow organ 5. Alternatively or additionally, the light emission section 22 can be equipped with only a few light sources or with a single, planar light source, which preferably covers the entire, or at least a large part, of the surface 33 and emits light not only from many individual points but also over a planar area.The rod-shaped light emission section 22 is designed such that at least a largely entire area 32 of the interior of the hollow organ 5 can be illuminated with light. A clear outer dimension 36, approximately a diameter, is adapted to the size of the access opening 34.

[0044] The light output is distributed across several essentially point-emitting light sources 37 in the form of LEDs, which are in turn distributed over the surface 33 of the rod-shaped light emission section 22. Alternatively or additionally, a single area-emitting light source, for example in the form of an OLED or a film with micro-LEDs, can be used, preferably extending over the entire surface 33 or large sections thereof. The light sources 37 shown here are preferably inorganic LEDs, all of which are selected such that their emission spectrum exhibits a particularly good overlap with the absorption spectrum of a photoactive substance used for photodynamic therapy. A cooling channel (not shown in Fig. 2a, b) is used to cool the light sources 37, in which a fluid is conveyed and at least some of the waste heat is dissipated. The cooling channel receives the fluid from the light source 37 and transports it away from the light source 37. The cooling channel is positioned in such a way as to optimize heat conduction from the light source 37 into the conveyed fluid.

[0045] This results in the total light generation being distributed across several, essentially point-emitting light sources 37, thus reducing or fractionating the electrical power consumption of each individual light source 37 and leading to lower partial heat output at the individual light sources 37. When using one or fewer area-emitting light sources, the total light generation is distributed across one or more comparatively large areas of the light source(s). By using at least one cooling channel, the individual light sources, especially when implemented as LEDs, can exhibit higher efficiency and achieve a higher luminous flux through targeted heat dissipation. In combination with distributing the light generation across several light sources 37 arranged on the outer surface 33, the total luminous flux can be increased.It is advisable to provide a number of light sources 37 on the outer surface 33 that can be realized within a maximum external dimension 36 and that, with sufficient cooling capacity, can provide the desired light output in virtually all directions. Furthermore, it is advisable to determine the actual number of light sources 37 used while considering the lowest possible manufacturing costs, particularly when designing the rod-shaped light emission section 22 as a disposable or single-use item.

[0046] By implementing such active heat management with forced convection, a minimum irradiance required for therapy can be achieved at each location even with limited external dimensions. The tissue segment to be treated and consequently a minimum total amount of light are provided. This allows for large-area irradiation of the entire inner surface of the hollow organ to be treated, even with a narrow access point. The fluid can be a gas or a liquid. The fluid can be conveyed by a pump, by pressure, or by gravity.

[0047] By using several distributed light sources 37, it is possible in a comparatively simple manner to achieve homogeneous irradiation of the inner surface of the hollow organ 5, even with more complex geometries or shapes. This can be achieved, for example, by varying the current intensity and consequently the light emission of the various light sources 37 in different axial subsections 101, 102, 103, and / or by varying the density / distribution or concentration of the light sources 37 in different axial subsections 101, 102, 103. Figure 2a shows, for example, a first axial subsection 101 in which the light sources 37 are arranged more densely than in a second subsection 102, which is located proximal (or alternatively distal) to the first subsection 101.Distal (or alternatively proximal) to the first subsection 101, a third subsection 103 is arranged in which the light sources 37 are arranged less densely than in the first subsection 101. The density of the arrangement of the light sources 37 can be varied in steps or gradually in the axial direction to suit the shape of the hollow organ 5 to be irradiated. The power supply unit 20 can be adjusted accordingly for the current supply, or the power supply unit 20 can be pre-programmed or pre-programmable according to organ-specific requirements.

[0048] In the embodiment shown in Fig. 2b, with a uniform density of the arrangement of the light sources 37, the light sources 37 could be supplied with a stronger current in a central or middle first axial subsection 101 of the rod-shaped light emission section 22, i.e., where the distance between the outer surface 33 and the inner surface of the hollow organ 5 to be irradiated is comparatively large, in order to adapt to the shape of the hollow organ 5 to be irradiated. In a second and / or third axial subsection 102, 103 of the rod-shaped light emission section 22 located distal and / or proximal to this, i.e., where the distance between the outer surface 33 and the inner surface of the hollow organ 5 to be irradiated is smaller, the light sources 37 could be supplied with a weaker current. A combination of the embodiments according to Figs. 2a, b is also possible.The power supply unit 20 can be adjusted accordingly for the current supply, or the power supply unit 20 can be pre-programmed or pre-programmable according to organ-specific requirements.

[0049] Fig. 3 shows another embodiment of an irradiation device 7 in a longitudinal section and a cross-section. A hollow organ 30 is shown, the internal tissue 31 of which is to be irradiated with light over a large area and simultaneously, i.e., not sequentially. The hollow organ 30 also has a relatively narrow access 34, is spherically shaped by way of example, and has a diameter that significantly exceeds the width of the access 34. The hollow organ 30 could be, for example, the bladder and the access 34 the urethra or an artificial access created, for example, during laparoscopy via the abdominal cavity.

[0050] The irradiation device comprises a rod-shaped light emission section 35, which can be inserted into the hollow organ 30. This section has a suitable outer dimension 36 for this purpose. Its longitudinal extent is adapted to the size of the hollow organ 30, so that it The entire area to be irradiated is at least largely covered. As shown in the embodiments according to Figs. 2a and 2b, the rod-shaped light emission section 35 has a plurality of light sources 37, which are distributed uniformly around the circumference of the rod-shaped arrangement 35. In the axial longitudinal direction, the distribution of the light sources 37 can be uneven (Fig. 2a) or uniform (Fig. 2b). In order to achieve homogeneous irradiation of the inner surface of the hollow organ 30 despite a uniform distribution of the light sources 37 in the axial longitudinal direction (Fig. 2b), the plurality of light sources 37 can, for example, be energized to different intensities depending on their axial position, which would result in varying light emission levels from the light sources 37. The curved inner wall of the hollow organ 30 can thus be irradiated homogeneously.It should be noted at this point that further embodiments are conceivable in which the light sources 37 are not evenly distributed in the circumferential direction, but for example only on one circumferential half of the rod-shaped light emission section 35, if a smaller area is to be illuminated.

[0051] The rod-shaped light emission section 35 has a rigid, exemplary cylindrical rod 72, on the outer surface 71 of which the light sources 37 are arranged. The rod 72 is surrounded by a transparent hollow cylinder 73, for example made of plastic, which, together with its outer surface 71, encloses a cooling channel 70 extending annularly around the rod 72. The hollow cylinder 73 is closed at the distal end of the rod-shaped light emission section 35 and has openings 75 there. A fluid is supplied from the proximal section 16 of the light emission section 35 and flows distally along the cooling channel 70. The fluid flows along the light sources 37 and absorbs heat loss through forced convection. from these. At the distal end, the fluid flows out of the openings 75 and enters the hollow organ 30.

[0052] Fig. 4 shows a slightly modified version of an irradiation device 8. Here, an additional outer shaft 76 is provided, which is arranged in the access point 34 and has an outlet 77 for the fluid. For this purpose, the outer shaft 76 is closed proximally and open distally. The outlet 77 is also arranged proximally, allowing fluid to enter the outer shaft 76 distally. The fluid, which enters the hollow organ 30 via the openings 75, is directed by a resulting pressure difference across the distal end of the outer shaft 76 to the proximal outlet 77.

[0053] The fluid used for cooling can enter the cooling channel 70 via an inlet 74, which is also located proximally. It is possible to additionally equip the inlet 74 and the outlet 77 with a shut-off device, a valve, or similar device, so that the fluid flow rate can be further controlled by actuating the respective shut-off device.

[0054] The power supply to the light sources 37 is provided, for example, via thin, flexible conductor tracks 78 arranged in grooves 80 running along the longitudinal direction of the rod 72 and connected proximally to the power supply unit 20. A protective layer 79, made of an electrically non-conductive medium transparent to the radiation from the light sources 37, such as silicone, is arranged on the rod 72 over the conductor tracks 78 and the light sources 37. This layer covers the conductor tracks 78 and the light sources 37, thus protecting them from external mechanical influences and electrically insulating them, particularly their electrical connections. The protective layer 79 is designed to be as thin as possible so that the cross-section of the cooling channel 70 is reduced as little as possible. This can potentially influence the flow resistance and minimize it. Furthermore, the light sources 37 are thermally integrated particularly well, thus improving the cooling effect.

[0055] In Fig. 5, which shows a further embodiment of the irradiation device 9, instead of the rigid rod 72 an arrangement of several spaced-apart rod segments is shown. 40 are provided, forming a segmented rod 48. This significantly increases the flexibility of the irradiation device. After insertion into the interior of the hollow organ to be treated, angulation can be achieved, for example, by Bowden cables or by the shape of the hollow organ. The rod segments 40 can also be made of a material with high thermal conductivity, such as metal. The individual rod segments 40 are connected to each other, for example, by a tube-like arrangement 41 made of an elastic material, such as silicone. To actually allow angulation, gaps 42 are provided between the individual rod segments 40, which can be made wider as the required angulation capability of the irradiation device 9 increases.

[0056] The light sources 37 are also arranged here in grooves 401, which are provided on the circumference of the individual rod segments 40 on their outer surfaces 81. Flexible conductor tracks 78 extend along the grooves 401 and bridge the gap 42. The cooling channel 70 is designed by way of example such that the tube-like arrangement 41 is designed as a coaxial double-tube arrangement comprising an inner tube 45 or inner sheath 45 and an outer tube 46 or outer sheath 46. To illustrate this, the cross-section of the rod-shaped light emission section 35 is shown on the right side of the drawing plane.

[0057] In addition to the further task of positioning and fixing the rod segments 40, the inner tube 45 is provided to protect the light sources 37 and their electrical connections. It is understood that the tubes 45 and 46 are designed to be as thin-walled as possible in order to minimize the lateral dimensions of the rod-shaped light emission section 35. Since the conductor tracks 78 are arranged in grooves 401, the inner tube 45 can be unprofiled. The embodiment shown here could also be implemented without grooves 401, in which case the inner tube 45 could be profiled.

[0058] The protective layer 79 from the previous embodiment can also be provided. It is particularly thin and designed such that the distance between the light sources 37 and the inner tube 45 is small. To prevent the fluid flow from being pinched and thus blocked, especially when the rod-shaped light emission section 35 is angled, and consequently from overheating the affected light sources 37, the outer tube 46 is supported at a predetermined distance from the inner tube 45 by webs 47 that extend along the longitudinal axis of the tube-like arrangement 41. This creates several first cooling channels 703 that are directly adjacent to the light sources 37. Second cooling channels 704 are formed that run between the light sources 37 and between the first cooling channels 703. The fluid can cool the light sources 37, particularly when flowing through the first cooling channels 703.Instead of the distal openings 75, a closed cooling system could also be created in which the second cooling channels 704 are used as return channels and the first cooling channels 703 as forward channels.

[0059] Fig. 6 shows another variant of an irradiation device 10, in which a single tube 49 has a greater wall thickness than The structure is a hollow cylinder. A volume formed between an inner wall 54 and an outer wall 55 comprises a plastic material with several circumferentially arranged, parallel recesses 701 extending along the longitudinal direction. These recesses 701 are, for example, tubular in shape and each serves as a cooling channel. Several of these recesses 701 are designated as first cooling channels 703, located directly adjacent to a light source 37. These recesses 701 can be used as a forward flow channel. Recesses 701 arranged between adjacent light sources 37, however, form second cooling channels 704 and function as return flow channels. This means that the rod-shaped light emission section 35 does not have any openings 75 at a distal end, but rather forms a closed cooling system.This makes it possible to use the system in organs where continuous rinsing with a liquid is otherwise unsuitable, such as the lungs. Furthermore, the risk of a cooling circuit becoming clogged by detached tissue fragments or other particles that can enter the circuit, as is known from open cooling systems, is virtually eliminated.

[0060] Figure 7 shows another embodiment of an irradiation device 1 1, in which the rod-shaped light emission section 35 is designed as a hollow body and has an inner radial section comprising a cavity 706, which also serves as a cooling channel 706. In this example, the cavity 706 functions as a forward flow channel 50 through which the fluid enters the cavity 706. It flows past light sources 37 on the inside, which are arranged in grooves 402 on a lateral surface 403 of an outer radial section of the light emission section 35. The fluid enters the hollow organ to be treated from distal openings 75, so that this serves as a return flow channel 51.

[0061] In addition to its use as a cooling channel, the cavity 706 can also be used for the at least temporary insertion of an imaging unit 52. This can be a conventional lens optic with a proximal image sensor unit, a flexible endoscope, or an arrangement specifically tailored to the application and design with a distal and / or proximal image sensor unit. The imaging unit 52 can be designed as a removable device or be permanently installed. A thin-walled, transparent tube 45 is also provided here as additional protection for the light source 37 and its electrical connections.

[0062] The rod-shaped light emission section 35 has a distal viewing window 53 through which the imaging unit 52 can look outwards, allowing a user to orient themselves when inserting the rod-shaped light emission section 35 into the hollow organ in order to position it correctly for therapy. It is also conceivable to use lateral viewing windows, which are not shown here. The imaging unit 52 can control the insertion and positioning of the rod-shaped light emission section 35. It can be rigid and guided by its stiffness, or it can be flexible and have control elements, such as a classic flexible endoscope. In the latter case, the rod-shaped light emission section 35 is preferably flexible. It is also conceivable to position the distal viewing window 53 obliquely, i.e., non-orthogonally, relative to the longitudinal axis of the rod-shaped light emission section 35. By rotating or...Rotating the rod-shaped light emission section 35 about its own axis during insertion and placement allows a larger area, i.e., an area with a larger solid angle, to be viewed. Preferably, the inclination of the viewing window 53 is adapted to selected imaging units 52, e.g., rigid endoscopic optics, with a corresponding oblique viewing direction. It is also conceivable to adjust the distal Viewing window 53 can be designed as a diverging lens. This also makes it possible to view a larger area. It is also conceivable to design the distal viewing window 53 as a hood. This also makes it possible to view a larger area.

[0063] The distal viewing window 53 can serve, among other things, as a distal stop for the imaging unit 52 inserted into the rod-shaped light emission section 35. If a corresponding stop is implemented, for example, in the proximal section 16, e.g., via a mechanical locking mechanism, the distal viewing window 53 can also be designed as an open distal or end-face opening – both in an orthogonal and oblique arrangement with respect to the longitudinal axis. In this case, the lateral openings 75 can be omitted; that is, the end-face opening can be used exclusively for the fluid to exit the cooling channel 706, or the end-face opening can be used in addition to the lateral openings 75 for the fluid to exit the cooling channel 706.The radial dimensions of cooling channel 706 and imaging unit 52 are coordinated in such a way that the cooling channel 706 can accommodate the imaging unit 52 at least temporarily for the period of correct placement of the light emission section 35 in the organ 30 to be treated.

[0064] Figure 8 shows a modification of the embodiment shown in Figure 7. Here, an irradiation device 12 is shown in which a rod 72 is provided, which is designed as a hollow body in the rod-shaped light emission section 35 and forms the cavity 706 shown in Figure 7 as the first cooling channel 706. A thin-walled hollow cylinder 73, transparent to the radiation from the light source 37, coaxially surrounds the rod 72, is closed distally, and has a distal viewing window 53. This creates a second cavity 707 as a second cooling channel 707 with an annular cross-section, which is used as a return flow channel 51. The first cavity 706, which functions as the forward flow channel 50, and the second cavity 707 are connected to each other via distal openings 75. Due to the closed design of the cooling system, the fluid does not come into direct contact with the patient at any point. Furthermore, the light sources 37 can be cooled simultaneously via both the forward flow channel 50 and the reverse flow channel 51, thus further increasing their performance.

[0065] The light sources 37 are arranged in grooves 502 formed on a lateral surface 503 of the rod 72. The grooves 502 extend in a longitudinal direction of the irradiation device 12.

[0066] Fig. 9 shows a modification of the embodiment from Fig. 8. Here, an irradiation device 13 is shown in which the rod 72 is segmented and has a series of annular segments 501 spaced apart longitudinally. These can be made of a material with high thermal conductivity, for example, a metal. The light sources 37 are placed directly or indirectly on a cladding surface 504 on this rod. The rod-shaped light emission section 35 is flexible due to the segmentation. The segments 501 are surrounded in flush contact by an inner, elastic, and transparent tube 45. Concentrically to this, an outer, transparent, and elastic tube 46 is arranged, which is held at a distance from the inner tube 45 by webs 47, similar to Fig. 5. The light sources 37 are electrically coupled by flexible conductor tracks 78 and arranged in grooves 505 directly on the segments 501.

[0067] The rod-shaped light emission section 35 includes the cavity 706 as the first cooling channel 706, which can be used as a forward flow channel 50 and for accommodating an imaging unit 52. The second cavity 707, which is located between the inner tube 45 and the outer tube 46 A second cooling channel 707 is formed and serves as a return flow channel 51. This creates a closed cooling system, and the light sources 37 are cooled by the fluid in both flow directions. However, it is conceivable to design this embodiment without the outer hose 45 and to omit the return flow channel 51.

[0068] To optimize the thermal connection of the light sources 37 to the fluid in the second cavity 707, the distance between the light sources 37 and the inner tube 45 is kept as small as possible. Furthermore, the space between the light sources 37 and the inner tube 45 is filled with a transparent material, such as silicone, whose thermal conductivity is many times higher than that of air. In addition, the inner tube 45 has the thinnest possible wall thickness.

[0069] Fig. 10 shows a further modified variant in the form of an irradiation device 14, in which a thin-walled, hollow rod 720 is spirally cut and fitted with light sources 37 along a surface 722. Here too, the hollow rod 720 can be made of a material with high thermal conductivity, such as a metal. Its spiral shape provides it with high flexibility. With a sufficiently thin rod 720, particularly good thermal coupling with the fluid is achieved.

[0070] The rod 720 has a first cavity 706, which functions as a first cooling channel 706 and is preferably a forward flow channel. The rod 720 is further surrounded by an elastic, transparent tube 45. Concentrically and at a radial distance therefrom, an outer tube 46 is provided, such that a second cavity 707 is formed between the tubes 45 and 46, which forms a second cooling channel 707 and in particular functions as a return flow channel. At a distal opening 75 of the first cooling channel 706, the cavities or cooling channels 706 and 707 are fluidically connected to each other (see block arrows in Fig. 10).

[0071] The inner tube 45 is profiled in the area of ​​the light sources 37, such that it is thin-walled in this area to minimize the thermal resistance between the light sources 37 and the second cooling channel 707. Preferably, the inner tube 45 and the outer tube 46 are held at a specific distance from each other by webs 47. More preferably, the inner tube 45, the outer tube 46, and the webs 47 are formed in one piece.

[0072] A flexible conductor track 78, electrically connected proximally to the power supply unit 20 for supplying electrical power to the light sources 37, can extend spirally along the rod 720 and is therefore guided on a solid substrate along its entire length. This minimizes stress on the conductor track when the rod-shaped light emission section 35 is bent, and in particular prevents it from kinking. By implementing only a single conductor track 78, which preferably has a low electrical resistance, manufacturing effort and costs can be minimized.

[0073] If desired or necessary, several spiral rods 720 can interlock and run parallel to each other. This can be achieved by increasing the pitch of the spiral shape of each of the rods 720 and / or by reducing their width. The light sources 37 can be arranged on all rods 720, so that the resulting individual strands are subjected to a lower electrical load. This variant can, for example, form the basis for a very powerful optical irradiation device that can be inserted under optical control into a hollow organ with a narrow and non-straight access, such as the The esophagus can be inserted and placed via the mouth and pharynx, or into a hollow organ that is itself characterized by many curves, such as the large intestine.

[0074] Figure 11 shows an embodiment of the irradiation device 15 with a rod 721, which is exemplarily made of a plastic. A lower thermal conductivity compared to metallic materials can be compensated for by a higher number of light sources 37, each with a lower radiant power, so that less heat loss occurs at each light source 37. The plastic construction particularly supports the design as a disposable or single-use item. The light sources 37 are arranged on a surface 723 of the rod 721.

[0075] The rod 721 is designed as a hollow body to utilize a first cavity 706 as a cooling channel 706 for forced convection. The first cavity 706 can function, for example, as a forward flow channel. In the illustration, a second cavity 707 is realized as a second cooling channel 707 around the rod 721 by means of an outer tube 461, which, as in previous embodiments, serves as a return flow channel.

[0076] To further reduce the temperature generated at the light sources 37, the fluid flow rate can be increased. The wall thickness of the rod 721 is made as thin as possible locally in the area of ​​the individual light sources 37 in order to minimize the thermal resistance between the light sources 37 and the fluid there. In addition, a protective layer 79 on the light sources 37 can be made as thin as possible to further minimize the thermal resistance between the light sources 37 and the fluid. The rod 721 also has, for example, additional recesses 85 on its inner surface in the area of ​​the light sources 37. the shape of indentations in the longitudinal direction to improve the thermal connection of the light source 37 to the cavity 706.

[0077] The rod 721 can also have a thin layer 90 with high thermal conductivity, thus improving the thermal connection of the light sources. The layer 90 can consist of a metallic material or a carbon allotrope, such as graphite.

[0078] The rod 721 can be made of a transparent plastic. Its position on an imaging unit 52 is therefore easily verifiable. Furthermore, the entire tissue surface can be inspected without changing the position of the rod-shaped light-emitting section 35. An additional, distally positioned viewing window 53, as in the preceding embodiments, can assist with insertion and placement in the hollow organ to be treated.

[0079] The rod 721 can be manufactured together with conductor tracks 78 as so-called MID parts (MID = Molded Interconnect Device). These are three-dimensional, injection-molded components in which the conductor tracks 78 are already integrated, thus eliminating the need for their separate production. MID technology is particularly suitable for the manufacture of rigid irradiation devices.

[0080] If an articulated, rod-shaped light emission section is desired, printed electronics could be used. For example, the rod 721 could be equipped with conductive traces 78 or printed with them. It is conceivable to arrange only one or a few light sources in the form of a planar organic LED (OLED) or a film with micro-LEDs on the rod 721, in addition to or as an alternative to the majority of point-emitting and distributed light sources 73. The rod 721 can achieve a high degree of [missing information] through suitable shaping. exhibit flexibility. However, if stiffness is to be increased, a mesh, for example made of metal wires, preferably elastic metal wires, can be incorporated into the rod 721 in a further embodiment. Depending on the thickness and arrangement of the wires, the stiffness can be varied almost arbitrarily and, if advantageous, locally. Furthermore, the flexibility could be influenced by selectively controlling an inlet and an outlet in combination with a correspondingly powerful pump, thereby selectively stiffening the rod by increasing the pressure in the cavities 706 and 707. Reference symbol list 1 light source (state of the art) 2 Light applicator (state of the art) 3 optical fibers (state of the art) 4 Scattering bodies (state of the art) 5 Organ / Hollow organ 6 Irradiation device 7 Irradiation device 8 Irradiation device 9 Irradiation device 10 Irradiation device 1 1 Irradiation device 12 Irradiation device 13 Irradiation device 14 Irradiation device 15 Irradiation device 16 proximal section 17 distal end 21 electrical transmission unit 22 rod-shaped light emission section 30 Hollow organ 31 internal tissue 32 entire area of ​​the interior of the hollow organ 33 Surface area 34 Access 35 rod-shaped light emission section 36 External dimensions 37 light bulbs 40 rod segment 41 tube-like arrangement 42 gaps 43 Surface area 45 inner tube / inner liner 46 outer hose / outer casing 47 Bridge 48 Staff 49 Hose / Hollow cylinder 50 inflows 51 Return / Return flow channel 52 imaging units 53 viewing windows 54 Inner wall 55 Exterior wall 70 Cooling channel 71 Surface area 72 staff 73 hollow cylinders 74 Admission 75 Opening 76 Outer shaft 77 Outlet 78 conductor track 79 Protective layer 80 Nut 81 Surface area 101 first subsection 102 second subsection 103 third subsection 401 Nut 402 Nut 403 Surface area 404 Segment 461 outer hose 501 segment 502 Nut 503 Surface area 504 Surface area 505 Nut 701 Recess 703 first cooling channel 704 second cooling channel 706 Cavity / Cooling channel / First cooling channel 707 second cooling channel 720 spiral rod 721 Staff 722 Surface area 723 Surface area

Claims

Claims: Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) for photodynamic therapy, comprising: a proximal section (16) and a rod-shaped light emission section (22, 35) arranged distal to the proximal section (16) for insertion into a hollow organ (5, 30), wherein the light emission section (22, 35) comprises a distal end (17), a cladding surface (33, 71, 81, 403, 503, 504, 722, 723), at least one electrically operable light source (37), at least one electrical conductor (78), and at least one cooling channel (70, 703, 704, 706, 707), wherein the at least one light source (37) is located on or radially inside the cladding surface (33, 71 , 81 , 403, 503, 504, 722, 723) is distributed to emit light from the lateral surface (33, 71 , 81 , 403, 503, 504, 722, 723) in several spatial directions, wherein the at least one light source (37) is connected to the at least one electrical conductor (78),which extends to the proximal section (16) of the irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15), and wherein the at least one cooling channel (70, 703, 704, 706, 707) is arranged in the light emission section (22, 35) and passes at least sectionally by the at least one light source (37) and is configured to conduct a fluid for absorbing heat from the respective light sources (37), wherein the light emission section (22, 35) has at least three axial subsections (101, 102, 103), wherein a first (101) of the subsections (101, 102, 103) is axially located between a second (102) of the subsections (102, 102, 103) and a third of the subsections (101 , 102, 103) is arranged, wherein, in the first subsection (101) a plurality of arranged distributed over the light emission section (22, 35) The light sources (37) are arranged more densely than in the second and third subsections (102, 103) and / or the irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) has a power supply unit (20) electrically connected to the light sources (37), wherein the power supply unit (20) is configured to supply the at least one light source (37) with a stronger electrical current in the first subsection (101) than in the second and third subsections (102, 103).

2. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claim 1, wherein the at least one light source (37) comprises at least one electrically operable light source extending over the light emission section (22, 35) and / or a plurality of light sources (37) arranged distributed over the light emission section (22, 35).

3. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claim 1 or 2, wherein the rod-shaped light emission section (22, 35) forms at least one hollow body which has at least one cooling channel (70, 703, 704, 706, 707).

4. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claim 3, wherein the at least one hollow body has a radially central cavity (706).

5. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claim 3 or 4, wherein the rod-shaped light emission section (22, 35) has a rod (48, 72, 720, 721) on which the at least one light source (37) is arranged, wherein the rod (48, 72, 720, 721) is at least partially surrounded by the at least one hollow body, and wherein the at least one hollow body is at least partially transparent to light.

6. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claim 5, wherein the rod (48, 72, 720, 721) has radially outer, axially extending grooves (80, 401, 402, 502, 505) in which the light sources (37) and / or the at least one electrical conductor (78) are arranged.

7. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claim 5 or 6, wherein the rod (48, 72, 720, 721) is hollow and forms one of the at least one hollow body.

8. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to one of claims 5 to 7, wherein the rod (48, 72, 720, 721) is rigid.

9. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to one of claims 5 to 7, wherein the rod (48, 72, 720, 721) is segmented in the axial direction, and wherein the at least one hollow body is designed to be flexible.

10. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to any one of claims 3 to 9, wherein the at least one hollow body has a hollow cylinder with an inner shell (45) and an outer shell (46) enclosing the inner shell (45), wherein the at least one cooling channel (70, 703, 704, 706, 707) is located between the inner shell (45) and the outer shell (46).

1. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claim 10, wherein the outer shell (46) is supported at least sectionally on the inner shell (45) to ensure a flowable cross-section of the at least one cooling channel (70, 703, 704, 706, 707). Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to any one of claims 3 to 11, wherein the at least one hollow body is a hollow cylinder (49) with an inner wall (54) and a outer wall (55) is, wherein there is a space between the inner wall (54) and the The volume formed by the outer wall (55) comprises a plastic material, and wherein several axially extending, parallel recesses (701) are arranged in the volume and spaced apart circumferentially, forming the at least one cooling channel (70, 703, 704, 706, 707). Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to one of the preceding claims, wherein the at least one cooling channel (70, 703, 704, 706, 707) comprises at least one forward flow channel (50) and one return flow channel (51), and wherein the at least one cooling channel (70, 703, 704, 706, 707) is closed to the outside. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claims 3 and 12, wherein the at least one forward flow channel (51) or the at least one reverse flow channel (51) is formed by the radially central cavity (706).Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to one of claims 1 to 11, wherein the at least one cooling channel (70,. 703, 704, 706, 707) in an outlet area near the distal end (17) of the rod-shaped light emission section (22, 35) is open to the outside, so that fluid conveyed in the at least one cooling channel (70, 703, 704, 706, 707) exits in the outlet area from the at least one cooling channel (70, 703, 704, 706, 707).

16. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to one of claims 3 to 14, wherein a closed or open viewing window (53) arranged transversely or obliquely to a longitudinal axis of the rod-shaped light emission section (22, 35) is arranged at the distal end (17), and wherein the radially central cavity (706) is dimensioned to accommodate an imaging unit (52) therein, at least temporarily.

17. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to claims 4 to 9, wherein the rod (48, 72, 720, 721) is spirally shaped.

18. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to one of the preceding claims, wherein the at least one light source (37) is covered by a transparent, electrically non-conductive protective layer (79).

19. Irradiation device (6, 7, 8, 9, 10, 11, 12, 13, 14, 15) according to one of the preceding claims, wherein the at least one light source (37) comprises at least one planar extending organic LED and / or an arrangement of a plurality of inorganic LEDs.

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