In an embodiment a therapeutic member includes a solitary radioactive seed. The seed includes a metallic housing with radioactive material contained within the metallic housing. The metallic housing has a first longitudinal end and a second longitudinal end and a longitudinal length between the first and second longitudinal ends. A polymeric material is molded to completely and monolithically encapsulate the metallic housing of the solitary radioactive seed. The implantable therapeutic member is adapted to be implanted into patient tissue using a hollow needle. A portion of the molded polymeric material extends from one of the first and second longitudinal ends of the metallic housing to reduce a tendency of the seed to migrate and rotate within a patient's body after implantation of the member. The portion of the molded polymeric material, that extends from one of the first and second longitudinal ends of the metallic housing, causes the implantable therapeutic member to have a longitudinal length that is greater than the longitudinal length of the metallic housing.