A delivery system and method for interstitial radiation therapy comprising substantially axially stiff and radially flexible elongated members made of material which is bioabsorbable in living tissue and a plurality of radioactive seeds dispersed in a predetermined array within the elongate member. The radioactive seeds can be dispersed within assembled half-shells made of the same material. The housing for the radiation seeds can also be manufactured from extruded material. A system for manufacturing the interstitial radiation therapy seed strands that automatically makes the seed strands is also provided. The delivery system and method further customize the member based on a prescription.