Abstract: A device for treating an occlusion or constriction, such as a stenosis in a blood vessel or other conduit within the body, as well as for treating a tumor or cancerous area occurring around a conduit or duct in the body is provided. The device includes an insert having a non-radioactive precursor, and a capsule encapsulating the insert. The precursor, containing tungsten which is substantially enriched in tungsten-180, can be activated to emit X-ray radiation and delivered to the treatment site to treat the stenosis or cancerous area. Upon activation by exposure to neutron flux, tungsten-180 is transmuted to contain an amount of X-ray-emitting tungsten-181 sufficient for treatment. The tungsten can also act as an X-ray-opaque marker to facilitate external visualization of capsule after delivery to the treatment site.

Abstract: A storage unit for a quantity of radioactive material in a capsule attached to a leader by which the capsule can be moved, the unit having a straight passage through a body of radiation-shielding material within which the radioactive material can be stored, and a shutter for one end of the passage that is operable between two limits in one of which it closes the passage and in the other of which it locates a hole in register with the passage. A spring-biased tube in the passage fits in a recess around the hole for retaining the shutter in the "open" position, and this tube can be pulled back from the shutter by a fitting attached to the capsule when the capsule is stored, releasing the shutter to return to the first limit. An interlock is provided to prevent accidental opening of the shutter.