A device for administering brachytherapy to a patient includes a vessel that may be in the form of a hollow cylindrical cup, for fleshing into and substantially filling the open-ended cavity. The vessel has a closed outer end, which may be a removable cover, and a source guide penetrates the closed outer end so as to extend deep into the vessel, to receive a radiation source in the source guide. A manipulator can be connected to the radiation source, and also to the source guide, for allowing several different types of manipulation of the source orientation and position within the vessel during the brachytherapy procedure.