Remotely operated brachytherapy system for oral cancer

This paper presents the development of a remotely operated brachytherapy system for oral cancer. The purpose of the system is to reduce exposure dose to the operator by keeping him or her at a distance of 1m from radioactive ¹⁹⁸Au sources. The system is designed to enable the operator to perform the same procedure as for conventional brachytherapy treatment without exposure dose. It consists of an applicator manipulator to implant ¹⁹⁸Au seeds, a finger device to firmly grasp organs in the mouth, operational parts for both of them, and a base arm. The applicator manipulator and finger device are fixed on the base arm which is fixed on a radiation shield. The applicator manipulator is a serial manipulator with five degrees of freedom (DOF). The finger device is necessary because organs in the mouth are soft and flexible. Its finger and operational parts are identical three DOF parallel manipulators. This paper details preliminary experiments of grasping and insertion with the system. These experiments verify that an operator can grasp a tongue model with the finger device and can insert the applicator into it with the applicator manipulator. In our developed system, we also confirm that rotation of the applicator needle can reduce insertion force.