Radiotherapy seeds and applicators

A stopper for controlling movement of a stylet relative to a brachytherapy needle, comprising:

• a body structure;
• a first connector on the body structure, for grasping a needle hub of the brachytherapy needle;
• and
• a second connector on the body structure, for grasping a stylet hub in a manner preventing the stylet from moving both proximally and distally relative to the brachytherapy needle.

A method of inserting a brachytherapy seed into body tissue, comprising:

• providing a needle with a brachytherapy seed therein, with a stylet inserted through a proximal end of the needle and with a stopper including a first connector for grasping a needle hub, and a second connector and a third connector for grasping a stylet hub, wherein the stopper is holding a hub of the stylet in the second connector, which prevents both distal and proximal movement of the stylet relative to the needle;
• inserting a tip of the needle into a tumor;
• pushing the hub of the stylet out of the second connector into the third connector, wherein the third connector prevents distal movement of the stylet hub in a different axial position of the stylet hub relative to the needle, than the second connector;
• and
• removing the stopper, to allow the seed to leave the needle and remain within the tumor.