An apparatus is described that efficiently resupplies radioactive seeds to a brachytherapy applicator. A seed-holding system includes a holder and a transfer device. The holder, which may be disposable, stores the radioactive seeds and the transfer device, which may be reusable, helps shield and dispense the seeds. The holder is coupled to the transfer device, and the apparatus is mated to an applicator. After seeds have been dispensed, the apparatus may be disconnected from the applicator and the empty holder may be ejected from the transfer device, and replaced with a full holder.