Patent Number: 051209730
Section: description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION In its simplest form the device according to the invention consists of a shielded loading and/or storage container 4 for radiation sources, which are not shown in detail. This container 4 is connected via a channel 16 with a switch 17 that can be operated by a drive motor 18. A switch of this kind is described in more detail in European Patent No. 0 128 300. From the switch 17 a further channel 9 leads via a coupling 10 and a connection plate 11 to an applicator 12. The side of the switch 17 remote from the channels 9 and 16 is connected, via a rotatable channel 22, a short channel section 43 and a release means 21, to a fork 20, the channels 23, 24 of which lead to respective drives 25, 26. Such drives are described in more detail, for example in German patent specification 33 35 438. By means of the drives 25, 26 thrust and traction wires (not shown}can be passed through the channels 23, 24, 43 and the rotatable channel 22 either via the channel 16 into the loading and/or storage holder 4 or via the channel 9 to an applicator 12. As shown in FIG. 2, the traction wire 33 moved by the drive 25 has at its end a bush 34 of slightly greater diameter than the traction wire 33 and continues as a pin 35 of smaller diameter. A needle-shaped holder 40 (FIG. 4) filled with radioactive material forms the radiation source that is to be brought from the loading and/or storage container 4 and inserted into the applicator 12. At the end of the needle-shaped holder 40 there is a sleeve 41 with inwardly-facing spring elements 42. The external diameter of the pin 35 is adapted to the internal diameter of the sleeve 41 so that on pushing the pin 35 into the sleeve 41 a clamping connection is formed. If the traction wire 33 is now advanced into the loading and/or storage container 4 by means of the drive 25, with the switch 17 appropriately set, the pin is pushed into the sleeve 41, since the needle-shaped holder 40 is in its end position. If the drive 25 is operated in the opposite direction the needle-shaped holder 40 can be withdrawn by means of the traction wire 33 until it reaches the release means 21. The release means 21 consists in its simplest form of a constriction before the fork 20 through which the cable 33 with the bush 34 and the pin 35 can pass, while the diameter of the sleeve 41 is so great that it strikes against the release 21. At this point the needle-shaped holder 40 is therefore caused to separate from the traction wire 33. The drive 26 is then switched on and the appropriate thrust wire 36(FIG. 3) pushes against the sleeve 41 with its bush 37 and a cylindrical extension 38. In the same way, the cylindrical extension 38 can carry a pin 39 with a diameter small enough for it not to be gripped by the inwardly-facing spring elements 42 of the sleeve 41 so as to avoid a coupling efffective in the direction of traction being reformed. By means of the thrust wire 36 the needle-shaped holder 40 can be moved into the applicator 12 after changing over the switch 17 with the rotatable channel 22. If the thrust wire 36 is now moved back into the starting position, the needle-shaped holder 40 remains in the applicator 12, so that the applicator coupling 10 can be released without difficulty, thus giving the patient with the applicator 12 considerably more freedom of movement. In FIG. 5 a form-locking coupling, effective in the direction of traction, is shown together with the associated release means 21. In this case the needle-shaped holder 40 has a slit sleeve 44, with resilient hooks 45 arranged in the slits. The resilient hooks cooperate with a locking groove 48 in a pin 47 at the end of a traction wire 46. FIG. 5 shows that the pin 47 can be pushed into the sleeve 44 between the resilient hooks 45, but after engagement of the resilient hooks 45 in the groove 48 is firmly connected to the traction wire 46 in the direction of traction. To release the needle-shaped holder 40 from the traction wire 46 the traction wire 46 is withdrawn far enough for oblique faces on the resilient hooks 45 reach the region of wedge surfaces 49 on the release 21. The resilient hooks 45 are thereby opened out and come out of the groove 48, and the traction wire can be released from the needle-shaped holder 40. A channel 43 on the release 21 provides sufficient space for the resilient hooks 45 to move apart in the region of the release 21, but elsewhere ensures precise guidance of the needle-shaped holder 40. FIGS. 6 and 7 illustrate the device according to the invention in detail. A housing 3 is mounted on a carriage 1 with rollers 2, leaving room on the carriage 1 for a shielded loading and/or storage container 4. The loading and/or storage container 4 is connected to the housing 34 through a tube 5. The loading and/or storage container 4 may, for example, have 16 storage channels 7 for radiation sources in the form of the needle-shaped holders 40 shown in FIG. 4. Inside the tube 5 are sixteen corresponding wire channels 6 running to the switch 17. From the same side of the switch 17 channels 15 lead to a connection plate 8, likewise for sixteen wire channels 9. These wire channels 9 end in the applicator coupling 10 which can be coupled to the connection plate 11 for the applicator channels. Sixteen applicators 12 in the form of needles are connected to this connection plate 11. The coupling 10 includes optical means for monitoring proper connection of the connection plate 11 with the coupling 10, in the form of an optical fibre 13 which runs from the coupling 10 to an optical fibre connection 14. This prevents thrust or traction wires and/or radiation sources from being moved out of the coupling 10 when this is not connected with the connection plate 11. In order to position the rotatable channels 22 precisely on the switch 17 for the connections for the channels 6 and 15, a catch 19 engages in the switch 17 in each position to which it is moved. Before each rotation of the switch, a test is carried out by means of a mechanical probe to ensure that there is no wire or radiation container in the switch. Since the wire channels to the patient being treated can be from one to three meters long, the thrust or traction wires moved by the drives 25, 26 must also be correspondingly long, so storage channels 27, 28 are provided on the back of the drives 25, 26 into which the thrust or traction wires can be passed until they come up against limit switches 29, 30 that switch off the drives 25, 26. The device is constructed in the form of a desk and has a front plate 31 carrying LCD indicators and buttons. A container 32 with an accumulator and an electronic control unit are housed in the lower part of the housing 3. By means of the device according to the invention radiation sources can be inserted into and withdrawn from applicators in a programmed manner, without the operators being exposed to radioactive radiation.