Patent Number: 061371149
Section: description

As shown in FIG. 1, the irradiation apparatus has a carrier plate 10, on which a transport module 2 that has a transport container 20 is disposed. Carrier plate 10 can pivot horizontally about a shaft 10' to facilitate the removal and insertion of transport module 2 (the outward-pivoted position is shown as a dashed line in FIG. 1). In the inward-pivoted state, the transport container is enveloped by an additional shield 3. Additional shield 3 has an additional-shield half 30, which is permanently connected to the irradiation apparatus, and an additional-shield half 32, which can swing out by means of a hinge 31. The two additional-shield halves 30 and 32 are embodied such that, when hinge 31 is in the open state, transport module 2 can pivot outward with carrier plate 10. However, the cuts of the two additional-shield halves 31 [sic] and 32 are configured such that the section planes do not intersect at least the storage position. of the radiation source, and possibly even transport container 20 (as shown in FIG. 1 and preferred in this regard). This prevents radiation from exiting along the section planes. The irradiation apparatus further has a housing 11 for diverse drives, at least for a transport cable, and diverse control units. Transport container 20 preferably includes an outside cylinder 21, which is bored through eccentrically and preferably comprises tungsten, and in which an inside cylinder 22 fits. A spiral-shaped cable channel is cut into the outside surface of inside cylinder 22. A transport and radiation-protection container of this type can also be used advantageously without the features of the dependent claims, and can be manufactured simply. This spiral-shaped cable channel 23 exits transport container 20 through a connecting cone 24 disposed on a surface of the cylinder formed by outside cylinder 21 and inside cylinder 22. As FIG. 4 shows, transport module 2 has beneath its transport container 20 a drive housing 25, in which assemblies for driving a transport cable 4 are disposed. A radiation source 4' is disposed at one end of transport cable 4. FIG. 4 shows radiation source 4' in its non-operative position. Disposed in drive housing 25 is a storage drum 40, onto and from which transport cable 4 can be wound and unwound. As explained below, transport cable 4 is pressed on storage drum 40 by a pressing band 41. A pressing roller 42, by way of which pressing band 41 is lifted from storage drum 40, is provided in the region of lifting point 42'. Pressing band 41 is guided back to storage drum 40 by means of deflection rollers 43, 44 and 45 and a drive roller 46. As is preferred, the side of pressing band 41 that rests against drive roller 46 is embodied as a toothed belt, which assures reliable driving of pressing band 41, and thus of storage drum 40 and transport cable 4. Behind lifting point 42', prior to entrance into transport container 20, transport cable 4 has a curved region, which forms a further impact sensor 5 that is described below. During normal operation, pressing band 41 is driven by means of drive roller 46, so that transport cable 4 is unwound from storage drum 40. In this way, radiation source 4' is moved out of its non-operative position, through the spiral-shaped cable channel 23 and connecting cone 24, and into a radiating position. Conversely, radiation source 4' can be moved back into its non-operative position by corresponding driving of drive roller 46. For securing radiation source 4' in its transport position during transport of transport module 2, the source has a stop lever 60 (FIG. 5) and a stop 62 on drive housing 25, between which a pin 61 located on storage drum 40 can be stopped when radiation source 4' is in its transport position. Stop lever 60 is further connected to a stop rod 63, which, by means of a gear 64, can press a further stop rod 65 into spiral-shaped cable channel 23, thus stopping transport cable 4. If transport module 2 is positioned on carrier plate 10, stop lever 60 can be pivoted by means of an unlocking pin 66. This pivoting stipulates that stop rod 65 releases transport cable 4 (FIG. 5). This pivoting of stop lever 60 also effects the release of storage drum 40 by pin 61 (this released state has not yet been attained in the representation of FIG. 5). If stop lever 60 has released pin 61, the storage drum can extend radiation source 4'. Storage drum 40 is displaced--as will be explained below in connection with FIG. 6--as it rotates, that is, during the movement of transport cable 4 parallel to the shaft 79 of the storage drum. Therefore, with respect to stop 62, pin 61 already has sufficient spacing to permit free rotation of storage drum 40 after one drum rotation. The spiral-shaped arrangement of pressing band 41 in a spiral-shaped cable-receiving groove 41' of storage drum 40 is shown schematically in FIG. 6. This figure shows pressing band 41 in section at the end of cable-receiving groove 41'. While pressing band 41 is guided in cable-receiving groove 41' over practically the entire length of the groove, in FIG. 6, transport cable 4 is only wound in the left region onto storage drum 40 (shown in a dashed line). In the region of lifting point 42' of the transport channel, pressing band 41 is also lifted from storage drum 40 by means of pressing roller 42 and deflection rollers 43, 44 and 45 and drive roller 46. As shown particularly in FIG. 6, pressing band 41 extends essentially in a plane perpendicular to storage-drum shaft 79. A guide part 49, which slides into cable-receiving groove 41', 41' as a guide shoe and is fixed to the housing, forces rotating storage drum 40 to perform a relative movement with respect to lifting point 42', so that storage drum 40 slides along its shaft (shaft 79) in the illustrated, preferred exemplary embodiment. Storage drum 40 is disposed to be displaced--namely, to slide--on storage-drum shaft 79, as indicated by the double-headed arrow A. In this way, lifting point 42' and the positions of pressing roller 42, deflection rollers 43, 44, 45 and drive roller 46 remain stationary, while, at 46', pressing band 41 returns into the pressing position in the part of cable-receiving groove 41" adjacent to lifting point 42. Mounted on the one side of storage drum 40 (shown as a dashed line in FIG. 7) is a holding element 47 that has a clamping channel 47' for transport cable 4 and a pressing-band holding element 47". A transport-band clamp 47'" is also mounted on this side of the storage drum, the clamp fixing transport band 4 with respect to storage drum 40. Mounted to the other side of storage drum 40 is a tensing device 48 for pressing band 41, which device includes a base plate 48' secured to storage drum 40 by means of screws 48A and onto which a clamping plate 48" having recesses that correspond to the toothing of the pressing band is fastened by means of screws 48B, so that the toothing of pressing band 41 engages the recesses and, in this way, the band is fixed in its position. As FIG. 9 shows, in a normal case, drive roller 46 and thus transport cable 4 are driven by way of a drive shaft 71 that is connected, fixed against relative rotation, to the roller, and a drive disk 71' that is connected to the drive shaft. Drive disk 71' has a toothing, which is engaged by a toothed belt 72. During operation, toothed belt 72 runs over a drive disk 73' mounted on a motor 73. Motor 73 can move between an ON position and an OFF position by way of a tension spring 73" and a pressure magnet 73'" such that, in the currentless state of pressure magnet 73'", drive disk 73' does not engage toothed belt 72, whereas pressure magnet 73'" brings drive disk 73' into engagement with toothed belt 72 during a current flux (FIG. 10). In an emergency, particularly in a power failure, drive shaft 71 is separated from motor 73 by this measure, and can be moved freely, for example to rewind transport cable 4 on storage drum 40. Even in the OFF position, removal of transport module 2 is very simple, because the module need not be separated from the transport-cable drive in a special step. To permit transport cable 4 and thus radiation source 4' to be brought into, for example, the transport or non-operative position in an emergency, the irradiation apparatus has an emergency drive. The emergency drive includes a coupling disk 79', which is connected to the storage-drum shaft 79 embodied as a torque shaft. A second coupling disk 78' is connected to a shaft 78, with shaft 78 being pressed with coupling disk 78' against the first coupling disk 79' by means of a compression spring 77. In contrast, coupling disks 78' and 79' are separated by means of a pull-type electromagnet 76, so that when current flows through pull-type electromagnet 76, the emergency drive is separated from the storage-drum shaft. Pull-type electromagnet 76 can release shaft 78 and thus couple in the emergency drive, particularly in the case of a power failure, but also, for example, through manual operation. For moving the transport cable, the emergency drive has a crank handle 74 and an emergency motor 75, which are connected to shaft 78 by way of toothed wheels 78". Of course, the individual features of the aforementioned transport-cable drive can be used advantageously, independently of the other features of the irradiation apparatus. Impact sensor 5 includes a curved region 50 of transport cable 4, which is guided in this curved region 50 in two elbows 51, which preferably have a bending radius of 4 cm and are spaced slightly from one another. Elbows 51 rest against stops 51' on the inside of the curve, but can be dislocated into a hollow space 52 provided on the outside of the curve. A tension spring 53 holds elbows 51 in their position with respect to stops 51'. If transport cable 4 impacts an object as it advances, it has the tendency to be dislocated into hollow space 52, that is, toward the outside of the curve. If the force exerted on elbows 51 by this movement exceeds the tensile force of tension spring 53, transport cable 4 and elbows 51 are dislocated into hollow space 52. This dislocation is detected by a switch 54. Switch 54 transmits a signal to the electronics of the irradiation apparatus, which prevents further pushing of transport cable 4 through storage drum 40. Transport container 20 has connecting cone 24, through which spiral-shaped cable channel 23 exits, for ensuring a connection between spiral-shaped cable channel 23 of the transport container and a connecting hose 29 that functions reliably and can be produced and released quickly. Moreover, the irradiation apparatus has a connecting cone 26, which can be placed onto connecting cone 24 (FIGS. 12 through 14). To increase the operator's comfort and the operating reliability, connecting cone 26 is connected to the rest of the irradiation apparatus by means of a movable arm 27. To ensure precise placement of connecting cone 26 on connecting cone 24, connecting cone 26 is connected to arm 27 by way of a cardan joint 28. In the center, connecting cone 26 has a cable channel 29', which transitions into a connecting hose 29. Cable channel 29' is disposed in a connecting piece 26' that is connected to the rest of connecting cone 26 by way of a ball bearing 26" for ensuring that connecting hose 29 can rotate with respect to connecting cone 26. The forces acting on connecting hose 29 and the connection between connecting cone 26 and connecting cone 24 can be reduced with this measure. Of course, with this type of connection of a transport container 20 with a connecting hose 29, a reliably functioning, easy-to-operate connection of a transport container 20 with a connecting hose 29 can also be effected independently of the other features of the irradiation apparatus. Extremely thin transport cables and short-range radiation sources in fiber form, particularly beta radiators, as are basically known from EP-A1-0 633 041, can be used with the storage drum according to the invention having a spiral-shaped pressing band. FIG. 15A shows the tip of a transport cable 4 of this type, which can also be curved in a J-shape, for example, for guiding a catheter around narrow curves. A glued, pressed or welded point 4" produces the connection between the fiber-type radiation sources 4' and drive cable 4. FIG. 15B shows a corresponding radiation source without a guide tip, and FIG. 15C shows a cross-section. In the specific embodiments of FIGS. 16 through 20, the spiral-type winding of transport cable 4 and pressing band 41 respectively covering only one winding of the transport cable is effected in a radial direction with respect to storage drum 40, so that transport cable 4 is guided narrowly between the part of an uninterrupted pressing band that covers and presses the cable radially from the outside and the radial outside of the winding of pressing band 41 that is respectively closest to the shaft. For this purpose, the two radially outside surfaces of pressing band 41 possess the complementary surface configuration that can be seen in FIG. 16, namely the preferred groove/spring arrangement of FIG. 16 that has a transport-cable guide groove 41A on the side of the "spring" 41B. This transport-cable and pressing-band guidance can be effected in various forms. For example, the part of the pressing band that does not yet cover or no longer covers the transport cable can be wound onto or unwound from a storage drum 40'. These specific embodiments are illustrated in FIGS. 17 through 20. To take into consideration the different radii, such as inevitably occur at the exit point 42' of the transport cable from storage drum 40 because of the "radial" unwinding process, in the specific embodiment of FIG. 17, it is provided that the two storage drums 40 and 40' are rotatably seated on a common rocker 80, on shafts that are spaced from one another. Exit point 42' remains fixed to the apparatus while storage drums 40 and 40' are guided behind, about the rotation point 81 of rocker 80 under the pulling force of a spring 82, corresponding to the increase or decrease in the radius of transport cable 4 and pressing band 41. The pressing band must guide the transport cable reliably under all operating conditions. Therefore, the pressing band should be subjected to a certain tensile stress. This tensile stress can be exerted, for example, by flat coil springs located in storage spools 40 and 40', which springs counteract one another; the spring force of the restoring coil should always be greater than the force of the advancing coil (FIG. 17). Another option is to generate the tensile stress through pre-stressed rollers that act on the pressing band (FIGS. 18 and 19). This is only possible, however, if the two spools 40 and 40' are mechanically coupled to one another. For this purpose, spools 40 and 40' are rotatably secured on a common drive shaft 23 [sic] in the specific embodiment of FIGS. 18 and 19. It is therefore necessary to dispose deflection rollers 43, 44 and 45 of pressing band 41 such that the pressing band can be guided back and forth between the storage drums 40 and 40' disposed with axial spacing--such as in a gear shift of a bicycle, but with only driving wheels and no driven wheels. Because of the changeable winding diameter on storage drums 40 and 40', the relative speed of storage drums 40 and 40' must change during winding and unwinding of the pressing band if the guidance path of pressing band 41 between the two storage drums is to be kept constant. A relative speed corresponding to the winding diameter can be attained with a gear having two spiral-shaped toothed wheels Z3 and Z4 according to FIG. 20. When pressing band 41 is wound, for example, in ten layers from storage drum 40 onto storage drum 40', the total rotation path of storage drum 40 can be transformed into a single revolution of the two spiral-shaped toothed wheels Z3 and Z4 through a gear reduction of 10:1 by means of toothed wheels Z1:Z2 or Z6:Z5. The variable transmission ratio of these two toothed wheels is selected such that the unwinding and winding speed of the two storage drums 40 and 40' is not a function of the winding diameter. ______________________________________ LIST OF REFERENCE NUMERALS ______________________________________ 10 carrier plate 41A transport-cable 10' shaft guide groove 11 drive housing 41' cable-receiving groove 2 transport module 41" cable-receiving groove 20 transport container 41B spring 21 outside cylinder 41C groove 22 inside cylinder 42 pressing roller 23 spiral-shaped cable channel 42' exit point 24 connecting cone 43 deflection roller 25 drive housing 44 deflection roller 26 connecting cone 45 deflection roller 27 arm 46 drive roller 28 cardan joint 47 holding element 29 connecting hose 47' clamping channel 29' cable channel of connecting cone 47" pressing-band 3 additional shield holding element 30 additional-shield 48 tensing device half, stationary 48' base plate 31 hinge 48" clamping plate 32 additional-shield half, hinged 48A screws 4 transport cable 48B screws 4' radiation source 49 guide part 4" glued, pressed or welded point 5 impact sensor 40 storage drum 50 curved region 40' storage drum 51 elbows 41 pressing band 51' stop 62 stop 52 hollow space 63 stop rod 53 tension spring 64 gear 54 switch 65 stop rod 60 stop lever 66 unlocking pin 61 pin 71 drive shaft 71' drive disk 72 toothed belt 73 motor 73' drive disk 73" tension spring 73''' pressure magnet 74 crank handle 75 emergency motor 76 pull-type electromagnet 77 compression spring 78 shaft 78' coupling disk 78" toothed wheel 79 storage-drum shaft 79' coupling disk 80 rocker 81 rotation point 82 spring 83 drive shaft ______________________________________