A fastener applicator includes a body portion including a handle assembly, a cartridge assembly supported within the body portion, the cartridge assembly including implantable fasteners, a drive assembly supported within the body portion and operatively coupled to the cartridge assembly to engage the implantable fasteners, and an actuation assembly supported within the handle assembly and operatively coupled to the drive assembly to fire a distal-most implantable fastener upon actuation of the actuation assembly. At least one of the implantable fasteners includes a body including a tissue facing surface, a tissue penetrating portion extending from the body, and a capsule affixed to the tissue facing surface of the body, the capsule including radioactive material.