Device for driving and positioning a source holder in an applicator used in radiotherapy

A device for driving and positioning a radioactive source holder in an applicator tube used in radiotherapy, the applicator tube having a first end and an open second end, said device comprising:

• a guide tube having one end connected to the second end of the applicator tube;
• a cable displaceable longitudinally along the guide tube and the applicator tube between a first position and a second position, the cable having a first end and a second end and the source holder being mounted on the cable in the vicinity of the first end;
• means for driving the cable along the guide tube and the applicator tube including a first drive roller in tangential and sliding contact with the cable, and means for rotating the first roller to drive the cable;
• an encoder having a second roller in tangential non-sliding contact with the cable and having means for detecting an interruption in the rotation of the second roller;
• and
• an end-of-course detector in front of which the second end of the cable is located when the cable is in the first position.

A device for driving and positioning a radioactive source holder in an applicator tube used in radiotherapy, the applicator tube having a first end and an open second end, said device comprising:

• a guide tube having one end connected to the second end of the applicator tube;
• a cable displaceable longitudinally along the guide tube and the applicator tube between a first position and a second position, the cable having a first end and a second end and the source holder being mounted on the cable in the vicinity of the first end;
• means for driving the cable along the guide tube and the applicator tube including a first drive roller in tangential and sliding contact with the cable, and means for rotating the first roller to drive the cable;
• an encoder having a second roller in tangential non-sliding contact with the cable and having means for detecting an interruption in the rotation of the second roller;
• and
• an end-of-course detector located to detect passage of the second end of the cable upon the cable moving beyond said second position.