Abstract: The present invention provides a device (10), and methods of use thereof, for the targeted delivery of radiation, in vivo. The therapeutic radiation delivered by the device (10) of the present invention can be used, for example, to prevent restenosis after angioplasty. The catheter device (10) of the present invention is especially suited for such treatment because it substantially aids in the delivery of radiation to an intravascular treatment site. In addition, to delivering radiation emitting materials to an intravascular site, the present invention can also incorporate radiation shielding to increase the safety and accuracy of the delivery of the radiation emitting materials.