WO2014069991A2

WO2014069991A2 - An esophagus applicator for brachytherapy

Info

Publication number: WO2014069991A2
Application number: PCT/NL2013/050755
Authority: WO
Inventors: Maarten Antonius Christiaan VAN DER ZANDEN; Wilhelmus Petrus Martinus Maria Van Erp; Cor Van De Wardt
Original assignee: Nucletron Operations B.V.
Priority date: 2012-10-29
Filing date: 2013-10-28
Publication date: 2014-05-08
Also published as: NL2009715C2; CN104768613A; WO2014069991A3

Abstract

The invention relates to an esophagus applicator for brachy therapy, comprising a molded plastic body comprising a proximal portion and a distal portion, said body accommodating a plurality of conduits, wherein at least one conduit from the said plurality of conduits is adapted to accommodate a displaceable radioactive source, and a further conduit from the said plurality of conduits is arranged to accommodate a guidewire, said proximal portion being connectable to an after loader device, said distal portion being substantially cone-shaped.

Description

Title: An esophagus applicator for brachytherapy FIELD OF THE INVENTION

The invention relates to an esophagus applicator for

brachytherapy.

The invention further relates to a method of manufacturing an esophagus applicator.

BACKGROUND OF THE INVENTION

In order to treat esophageal cancers, generally, one may use high- dose rate (HDR) brachytherapy to provide precise radiation therapy while sparing surrounding healthy tissues. This type of internal radiation therapy allows for high doses of radiation to be placed in or around esophageal cancer to accurately destroy the cancerous cells. HDR brachytherapy allows administering high doses of radiation with minimal exposure to healthy tissues neighboring the esophagus, such as lungs, heart and stomach.

HDR brachytherapy uses displaceable sources which may be positioned in the body using suitable conduits, applicators, needles or the such. The conduits, applicators, needles are positioned inside the target volume (i.e. the volume that has to be treated with brachytherapy), which ensures that the pre-planned dwell positions for the displaceable sources spatially coincide with the target volume. The radioactive sources are left on or around the tumor to deliver the pre-planned amount of radiation

(therapeutic dose). One usually uses computer guidance and planning systems to control how far the sources penetrate into the pre-positioned catheters and how long they stay in the catheters. Embodiments of suitable esophagus applicators are known from Nucletron, Applicator's Guide, version 308880 [08], 2011.

Difficulties encountered during swallowing constitute a common side effect of esophageal cancer radiation treatment. A feeding tube is often inserted before radiation treatment occurs. In some cases an esophageal stent can be inserted after treatment to keep the esophagus open.

It is a disadvantage of the known esophagus applicators that introduction thereof is only possible by swallowing. Usually this is

implemented by using an endoscope for inserting of a guide wire through the patient's mouth into esophagus. Then, using the pre-inserted guide wire, the applicators or catheters are guided into position and the guide wire is removed from the patient. For example, this procedure is followed when a per se known Bonvoisin-Gerard Esophagus applicator of Nucletron is used. However, due to cancer proliferation the diameter of the esophagus might decrease which causes substantial impediment for swallowing the state of the art esophagus applicators.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved esophagus applicator for brachytherapy. More in particular, it is an object of the invention to provide an esophagus applicator which is easy to insert and to maneuver for treating a target region. Still more in particular, it is an object of the invention to provide an esophagus applicator, which is multi- functional. Still more in particular, it is an object of the invention to provide the applicator which is capable of delivering an improved dose distribution within the target volume.

To this end the esophagus for brachytherapy according to an aspect of the invention comprises a molded plastic body comprising a proximal portion and a distal portion, said body accommodating a plurality of conduits, wherein at least one conduit from the said plurality of conduits is adapted to accommodate a displaceable radioactive source, and a further conduit from the said plurality of conduits is arranged to accommodate a guidewire, said proximal portion being connectable to an afterloader device, said distal portion being substantially cone-shaped. It is found that when providing the applicator with a common body accommodating a plurality of lumens provided there within, the applicator's insertion may be simplified substantially. For example, it is found that such applicator may be inserted via the patient's nose, similar to introduction of the per se known Nasal jejune Feeding tube. It will be appreciated that in order to enable a nasal insertion of the applicator its cross-sectional dimensions should preferably he in the range of about 0.2 - 0.6 cm. It is further found that by providing the body as a molded structure, the inner lumens may be manufactured instantly, which reduces the production costs and ensures geometrical consistency of the applicator as a whole. It will be appreciated that, preferably, the esophagus applicator comprises a plurality of lumens - two, three, four, five or more lumens adapted to accommodate a radioactive source in use.

In the esophagus applicator the body comprises a proximal portion and the distal portion. Preferably, the proximal portion is provided with a secure mechanism, such as a transfer tube, for connecting the lumens of the applicator to a dose delivery channel of an afterloading device. By shaping the distal portion as a cone, introduction of the applicator is further simplified, improving the patient's comfort. The applicator according to the invention is inserted into the patient using a guidewire. The guidewire may be pushed through a dedicated lumen provided in the body during

manufacture thereof.

In an embodiment of the applicator according to an aspect of the invention the lumen provided for the guidewire extends through the distal portion of the molded body obliquely with respect to a longitudinal axis of the body.

It is found that by providing the guidewire lumen cutting through the distal portion of the molded body, handling of the esophagus applicator by a medical specialist is substantially relaxed. First, in this configuration, the medical specialist has a full visual control on the guidewire and the body prior to insertion of the latter into the patient. Secondly, because the guidewire runs obliquely with respect to the longitudinal axis of the body, it does not interfere with the dose delivery lumens, which is advantageous.

In a still further embodiment of the applicator according to the invention the lumens are at least partially displaceable with respect to each other.

This technical measure is based on the insight that it may be advantageous to provide a degree of freedom to the lumens inside the esophagus so that the lumens find their own way about the target volume. It will be appreciated that the esophageal cancer generally presents a substantially spherical object which protrudes through the esophagus wall inwardly. Accordingly, the displaceable lumens will generally surround the cancerous mass, thereby yielding an improved dose distribution within the target region.

In a still further embodiment of the applicator according to a further aspect of the invention the lumens are interconnected by a

degradable material which disintegrates in use thereby disconnecting the lumens from each other.

It is found to be particularly advantageous to provide the applicator having a minimal cross-section during the step of introduction of the applicator into the esophagus. However, when the applicator is introduced, it is advantageous that the lumens adapted to accommodate a radioactive source are displaceable with respect to each other. Accordingly, a suitable (bio)degradable material may be used for maintaining the lumens close to each other during introduction. When the (bio)degradable material is destroyed, the lumens may displace with respect to each other and may take an optimal spatial position surrounding the target volume.

For example, the applicator may be formed such that the body comprises a unitary distal end and a plurality of proximal ends. This configuration is explained in more details with reference to Figure 6. Alternatively, the applicator may comprise the body having a unitary distal end and a unitary proximal end, the lumens running between the unitary distal end and the unitary proximal end are displaceable with respect to each other. This configuration is explained in more detail with reference to Figure 7. This configuration has an advantage that the proximal ends of the applicator are kept together during treatment minimizing the risk of interchanging them by the medical specialist.

Preferably, each proximal end is suitably coded for identification purposes.

In both configurations each lumen adapted to accommodate a radioactive source runs from the unitary distal end to the respective proximal end or the unitary proximal end thereby yielding a plurality of substantially mutually displaceable lumens. Preferably, the applicator comprises two, three, four, five or more lumens adapted to accommodate the radioactive source.

In a still further particular embodiment of the applicator according to a further aspect of the invention, the body and/or the individual lumens are provided with a centering unit for centering the at least one lumen inside an organ in use.

It will be appreciated that when the lumens are fixed inside the body, it is sufficient to provide the centering unit on the body itself. In the alternative embodiment, when the lumens are mutually displaceable, it may be advantageous to provide the centering units on the respective lumens.

It is found to be particularly advantageous to provide the applicator which may be auto-centered inside the esophageal conduit.

Preferably, for the centering unit is a three-dimensionally shapeable object. This feature has an advantage that the shapeable object has some resiliency which results in an improved patient's comfort. Preferably, the shapeable object is an inflatable balloon, a sponge, a torsion spring, a key bolt or one or more displaceable projections. These embodiments are discussed in more detail with reference to Figures. In a still further embodiment of the applicator according to a still further aspect of the invention, at least one lumen from the said plurality of lumens comprises a shielding element for substantially intercepting radiation.

It is found to be particularly advantageous to provide the esophagus applicator, which is capable of delivering asymmetrical dose distribution patterns. It will be appreciated that esophagus is anatomically positioned close to a number of critical organs, such as heart, stomach, etc. Accordingly, for deeply seated tumors, it may be advantageous to allow for dose deposition in a preferred direction, while having one or more directions (away from the source) spared from radiation. Preferably, a shielding element is a heavy-Z material, such as Tungsten. It will be appreciated that the shielding may be provided as a continuous piece of material, or, alternatively, shielding may be implemented from segments. The segments may be interdigitated, or chain-like. Still alternatively, shielding material may be provided as powder in a specific pre-manufactured pocket of the applicator wall. This feature improves flexibility of the applicator adding to patient's comfort during treatment.

In a still further embodiment of the applicator according to a still further aspect of the invention at least one lumen from the said plurality of lumens comprises a radiation dose measuring device.

It is found to be particularly advantageous to provide a real-time dose measurement device, which is positioned inside or near the target volume. Accordingly, dose deposited from the radioactive sources positioned in the esophagus applicator according to the invention may be accurately measured by the detector thereby providing independent information on the actual dose delivery. Preferably, an array of detector elements is provided. Alternatively, or additionally, the detector elements may be provided within different adjacent lumens. The method of manufacturing an esophagus applicator, according to an aspect of the invention comprises the steps of:

- molding a plastic body comprising a proximal portion and a distal portion, wherein the distal portion is substantially cone-shaped;

- co-molding a plurality of conduits in the said body,

- adapting at least one conduit from the said plurality of conduits is adapted to accommodate a displaceable radioactive source;

- adapting a further conduit from the said plurality of conduits to accommodate a guidewire,

- adapting proximal portion to be connectable to an afterloader device.

In an embodiment of the method according, wherein the applicator comprises at least two conduits adapted for accommodating the radioactive source, the method further comprises the step of interconnecting the said conduits using bridges or three-dimensional bodies.

These and other aspects of the invention will be discussed with reference to drawings wherein like reference numerals or signs relate to like elements. It will be appreciated that the drawings are presented for illustration purposes only and may not be used for limiting the scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 presents in a schematic way an embodiment of the esophagus applicator according to an aspect of the invention.

Figure 2 presents in a schematic way a further embodiment of the esophagus applicator.

Figure 3 presents in a schematic way a still further embodiment of the esophagus applicator comprising a shielding element.

Figure 4 presents in a schematic way a still further embodiment of the esophagus applicator. Figure 5 presents in a schematic way an embodiment of the esophagus applicator provided with an obliquely extending guidewire.

Figure 6 presents in a schematic way an embodiment of the esophagus applicator comprising mutually displaceable lumens.

Figure 7 presents in a schematic way a further embodiment of the esophagus applicator comprising mutually displaceable lumens.

Figure 8a presents in a schematic way a still further embodiment of the esophagus applicator comprising a plurality of lumens.

Figure 8b presents in a schematic way a still further embodiment of the esophagus applicator comprising a plurality of lumens.

Figure 9 presents in a schematic way a still further embodiment of the esophagus applicator, wherein a plurality of lumens is interconnected by three-dimensional bodies. DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 presents in a schematic way an embodiment of the esophagus applicator according to an aspect of the invention. The esophagus applicator 10 for brachytherapy, comprises a molded plastic body 2

comprising a proximal portion 6 and a distal portion 4, said body

accommodating a plurality of conduits 3, 5, wherein at least one conduit 3 from the said plurality of conduits is adapted to accommodate a displaceable radioactive source, and a further conduit 5 from the said plurality of conduits is arranged to accommodate a guidewire. The proximal portion 6 is connectable by means of portion 9 to an afterloader device (not shown) and the distal portion 4 is substantially cone-shaped, see view A.

In view B a cross-section of the esophagus applicator shown in view A is presented. The plurality of conduits may comprise a sole source conduit 3 and a sole guidewire conduit 4. However, preferably, the plurality of conduits comprises a plurality of source conduits (shown in Figures 2 and 3) and a guidewire conduit. In view C an embodiment of a placement of the guidewire on the distal portion 4 of the applicator 10 is shown. Preferably, the oblique angle a between the axis of the guidewire conduit 5 and the longitudinal axis X of the body 2 lies between 5 and 30 degrees, more preferably between 10 and 20 degrees.

Cross-sectional dimensions of the source conduits 3 extending in the body of the applicator 10 may be custom selected, depending on the outer diameter of the source which is intended to be positioned within the conduits 3. The sources are preferably automatically transported via a connection tube 9, interconnecting an afterloader device (not shown) and the proximal portion of the body 2.

Figure 2 presents in a schematic way a further embodiment of the esophagus applicator. The esophagus applicator 20 comprises a body 21 having a (central) guidewire lumen 22, which is open at a distal portion 22a of the body 21. The body 21 further comprises a first source lumen 24 and a second source lumen 23 for accommodating corresponding sources for enabling dose delivery. Those skilled in the art would readily appreciate in which way the sources may be stabilized inside the lumens 23, 24. It will be appreciated that the guidewire lumen 22 and the lumens for accommodating a radioactive source may be provided asymmetrically within the body 21.

Figure 3 presents in a schematic way a still further embodiment of the esophagus applicator 30 comprising a shielding element. In the present embodiment the body 31 comprises a central guidewire lumen 32 and two lumens 33, 34 for accommodating the radioactive source. In the right hand side view a cross-section of the esophagus applicator is

schematically presented. The cross-sectional portion of the body 35 may comprise a shielding element 36, which may be firmly attached to the body 35 at a pre-defined position. The shielding element 36 may extend along a desirable portion of the cross-section 35. Alternatively, the shielding element may be provided within a suitable lumen and may be displaceably arranged there within. Still alternatively, suitable shielding may be achieved by providing a portion of the applicator's wall with a powder of a shielding material. It will be appreciated that the powder may be pre- inserted during manufacturing of the applicator, or, alternatively, it may be inserted during use. The advantage of the former embodiment is that minimum handling is required. The advantage of the latter embodiment is that the location shielding may be adapted on demand. Still alternatively, the solid shielding may be provided, which may be displaceable in the applicator. For example, a suitable wire may be attached to the shielding material. In use, the medical specialist may suitably displace the shielding by pulling or pushing the wire. This has an advantage that the local shielding may be adjusted during a procedure, for example, when it is found that there is a longitudinal mismatch between the pre-planned dwell positions of the sources within the application and the actually expected positions.

Figure 4 presents in a schematic way a still further embodiment of the esophagus applicator 40, wherein centering elements are provided. View "a" depicts schematically an embodiment of the esophagus applicator having a body 41 and at least one source lumen 42, wherein an inflatable balloon 43 is provided for urging the applicator to stay within its parked position inside a patient. The balloon 43 may be inflated by a gas or by a suitable liquid, such as saline.

View "b" presents in a schematic way an embodiment of the esophagus applicator having a body 41 and a source lumen 42b, wherein two projections 44a, 44b are provided as anchors. The projections 44a, 44b serve for a substantial centering of the applicator within the esophagus. The projections may be auto-deploying, for example, in response to a slight pull of the applicator backwards. It will be appreciated that any suitable number of pairs of projections described above may be provided along the length of the applicator. View "c" presents in a schematic way a still further embodiment of the esophagus applicator, wherein a plurality of projections 46a, 46b, 46c, 46d, 46e, 46f is provided substantially along the same cross-section of the applicator. These projections are adapted to act as an umbrella, when the applicator is pulled backwards, as is schematically indicated by arrows F. It will be appreciated that it may be advantageous to use an umbrella-like centering unit because the force induced on the esophagus will be

substantially equally distributed along the esophagus lumen. This may increase the patient's comfort during the procedure.

View "d" presents schematically a still further embodiment of the centering elements, wherein an irregularity, such as a bump, is provided on the external surface of the body 42. By pulling the body backwards, the initially flat structure may undergo deformation and a bump may be formed. This bump may be circumferential, which improves centering of the applicator inside the esophagus.

It will be further appreciated that other embodiments of the centering element may be envisaged next, or in place of the ones described above. For example, the sleeve may comprise a specifically arranged lumen for ejecting a centering element, such as a sponge, a torsion spring which may deploy upon ejection from the lumen, a key bolt, or the like. Those skilled in the art would readily appreciate which modifications of the centering elements are possible.

Figure 5 presents in a schematic way an embodiment of the esophagus applicator 50 provided with an obliquely extending guidewire. In this particular embodiment the body 51 comprises an oblique guidewire lumen 52, which is adapted to provide a guidewire port substantially externally from the body of the sleeve. This found advantageous because the guidewire lumen does not interfere with the source delivering lumens 53. The applicator 51 may further comprise radiation detectors 54a, 54b for providing real time information on the dose delivered inside the patient during treatment.

Figure 6 presents in a schematic way an embodiment of the esophagus applicator 60 comprising a plurality of mutually displaceable conduits 63a, 63b, 63c. The esophagus application is manufactured using a molding process. In this particular embodiment the applicator 60 comprises a unitary distal end 62a, wherein all lumens are terminated. It will be appreciated that in the clinical procedure the distal end 62a is to be inserted distally with respect to the treatment volume. The treatment volume is surrounded by the isolated displaceable lumens 63a, 63b, 63c.

In this particular embodiment the applicator 60 comprises a proximal portion 62b which is constituted by the free proximal ends of the lumens 65a, 65b, 65c. The medical specialist suitably handles the proximal ends 65a, 65b, 65c to connect them to an afterloader device (not shown) for supplying a radioactive source inside the respective lumens.

The esophagus applicator 60 is adapted to be inserted through the patient nose into or near the target volume. For this purpose the esophagus applicator may comprise a guidewire (not shown). The guidewire may be provided thorough an inner conduit, having an open end at a distal portion of the distal portion 62a of the applicator, or it may be provided

substantially at an external surface of the applicator, as is depicted in Figure 5.

The applicator 60 may be provided with one or more centering elements, which are discussed with reference to Figure 4.

Figure 7 present schematically a still further embodiment of the applicator according to a still further aspect of the invention. In this particular embodiment the applicator is depicted within the esophagus 70 having a cancerous mass 75. The applicator comprises a proximal unitary end 71 connecting all proximal ends of the source lumens 73a, 73b, 73c, 73d and a distal unitary end 72 connecting all distal ends of the source lumens 73a, 73b, 73c, 73d.

As has been explained in the foregoing the lumens 73a, 73b, 73c, 73d may be manufactured as being separate bodies, interconnected by the proximal and distal ends. However, it may be advantageous to temporarily interconnect the lumens 73a, 73b, 73c, 73d substantially along their length for relaxing insertion of the esophagus applicator inside the patient. The temporarily interconnected lumens 73a, 73b, 73c, 73d may be attached to each other using a (bio)degradable material, which may be substantially instantly destroyed by the body fluids when the lumens are inserted in esophagus. Alternatively, the (bio)degradable material may be forced to disintegrate by flushing the applicator with a suitable fluid, such as water, saline or the like.

View A shows schematically the arrangement of the applicator in a longitudinal projection. In view B a cross-sectional projection is shown. It is seen, that due to the fact that the source lumens 73a, 73b, 73c, 73d are mutually displaceable they surround the cancerous tissue in three- dimensions, which leads to an improved dose distribution within the target volume.

Figure 8a presents in a schematic way a still further embodiment of the esophagus applicator comprising a plurality of lumens. In this particular embodiment, the esophagus applicator 80 comprises three lumens 81a, 82a, 83a adapted to receive a radioactive source (not shown). The lumens are bridged together by means of local bridges 84a, 84b, 84c. This embodiment has an advantage that the lumens may be displaceable with respect to each other between bridged portions. Accordingly, these

displaceable portions may distribute themselves about the lesion in a way schematically depicted in Figure 7. It will be appreciated, however, that the lumens 81a, 82a, 83a may alternatively be bridged along the whole length, or, at least along the portion of the lumen which receives the source in use. This has an

advantage that the overall cross-sectional dimension of the esophagus applicator is minimized yet preserving the pre-determined spatial

orientation of the lumens with respect to each other.

The lumens 81a, 82a, 83a are formed in the respective wall members 81, 82, 83, which are preferably co-molded. The bridging

structured 84a, 84b, 84c are preferably integrated with the outer envelopes of the lumens 84d, 84e, 84f. The envelopes and the bridging elements are preferably co-molded with the lumens. The bridging structures are preferably elastic.

One or more of the lumens walls 81, 82, 83 may be provided with a compartment for accommodating a shielding element 180. As is described with reference to the foregoing, the shielding element may be implemented as a suitable powder, chain, wire, stripe, or the like. Those skilled in the art would readily appreciate the suitable position and dimension of the shielding element in the wall. It will be appreciated that the shielding element may cover a sector or a whole perimeter of the lumen's wall. More in particular, it will be appreciated that any lumen may be provided with the shielding element 190.

Figure 8b presents in a schematic way a still further embodiment of the esophagus applicator comprising a plurality of lumens. In this particular embodiment the esophagus applicator 85 comprises three source lumens 86a, 87a, 88a adapted to receive a radioactive source in use. In this embodiments no additional envelope is provided to form the bridging structures 89a, 89b, 89c. The bridging structures 89a, 89b, 89c are

preferably co-molded with the walls 86, 87, 88 wherein the lumens 86a, 87a, 88a are formed. The bridging structures are preferably elastic. It will be appreciated that the dimension of the bridging

structures 89a, 89b, 89c may be variable along the length of the esophagus applicator thereby optimizing the local cross-sectional dimension of the applicator.

Figure 9 presents in a schematic way a still further embodiment of the esophagus applicator, wherein a plurality of lumens is interconnected by three-dimensional bodies. For ease of comprehension a plane view is provided wherein the applicator 90 is unfolded. It will be appreciated that in use the applicator 90 is rolled-up, connecting the lumen 94 to the lumen 90.

In this particular embodiment the esophagus applicator 90 comprises a plurality of lumens 91, 92, 93, 94 having cone-shaped ends 9 Id, 92d, 93d, 94d. Each lumen is provided with a set of three-dimensional bodies 91a, ...9 In; 94a, ...94n. The three-dimensional bodies may be spheres, triangles, blocks and so on. The three-dimensional bodies are inter- linked by means of bridging structures 95a, 95b, 95c. It will be appreciated that the three-dimensional bodies may also be interlinked with bridging structures along a length of a single lumen.

It is found that by provision of the three-dimensional bodies interlinking the lumens 91, 92, 93, 94 an improvement of the dose

distribution in a cross-sectional direction C-C is achieved. Preferably, the three-dimensional bodies are co-molded with the lumens.

While specific embodiments have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described in the foregoing without departing from the scope of the claims set out below.

Claims

1. An esophagus applicator for brachytherapy, comprising:

- a molded plastic body comprising a proximal portion and a distal portion, said body accommodating a plurality of conduits, wherein at least one conduit from the said plurality of conduits is adapted to accommodate a displaceable radioactive source, and a further conduit from the said plurality of conduits is arranged to accommodate a guidewire, said proximal portion being connectable to an afterloader device, said distal portion being substantially cone-shaped.

2. The applicator according to claim 1, wherein the lumen provided for the guidewire extends through the distal portion of the molded body obliquely with respect to a longitudinal axis of the body.

3. The applicator according to claim 1 or 2, wherein the lumens are at least partially displaceable with respect to each other.

4. The applicator according to claim 1 or 2, wherein the lumens are interconnected by a degradable material which disintegrates in use thereby disconnecting the lumens from each other.

5. The applicator according to claim 3 or 4, wherein the body comprises a unitary distal end and a plurality of proximal ends.

6. The applicator according to claim 3 or 4, wherein the body comprises a unitary distal end and a unitary proximal end, the lumens running between the unitary distal end and the unitary proximal end.

7. The applicator according to claim 5 or 6, wherein each lumen adapted to accommodate a radioactive source runs from the unitary distal end to the respective proximal or the unitary proximal end thereby yielding a plurality of substantially mutually displaceable lumens.

8. The applicator according to claim 7, comprising one or more lumens adapted to accommodate the radioactive source.

9. The applicator according to any one of the preceding claims, wherein each lumen adapted to accommodate the radioactive source comprises an individualized radiopaque marker.

10. The applicator according to any one of the preceding claims, further comprising a centering unit for centering the body or respective mutually displaceable lumens inside an organ in use.

11. The applicator according to claim 10, wherein the centering unit is a three-dimensionally shapeable object.

12. The applicator according to claim 11, wherein the shapeable object is an inflatable balloon, a sponge, a torsion spring, a key bolt or one or more displaceable projections.

13. The applicator according to any one of the preceding claims, wherein at least one lumen from the said plurality of lumens comprises a shielding element for substantially intercepting radiation emanating from the radioactive source in use.

14. The applicator according any one of the preceding claims, wherein at least one lumen from the said plurality of lumens comprises a radiation dose measuring device.

15. The applicator according to any one of the preceding claims, comprising at least two lumens adapted for accommodating a radioactive source, wherein the lumens are at least partially interconnected.

16. The applicator according to claim 15, wherein the lumens are interconnected by bridge structures.

17. The applicator according to claim 15, wherein the lumens are interconnects by three-dimensional bodies.

18. The applicator according to claim 17, wherein the three- dimensional bodies are spheres.

19. A method of manufacturing an esophagus applicator, comprising the steps of:

co-molding a plurality of conduits in the said body,

adapting at least one conduit from the said plurality of conduits is adapted to accommodate a displaceable radioactive source;

adapting proximal portion to be connectable to an afterloader device.

20. The method according to claim 19, wherein the applicator comprises at least two conduits adapted for accommodating the radioactive source, the method further comprising the step of interconnecting the said conduits using bridges or three-dimensional bodies.