This file was derived from: Teletherapy Capsule.jpgA diagram of a typical teletherapy radiation capsule comprised of the following:

A) an international standard source holder (usually lead),
B) a retaining ring, and
C) a teletherapy "source" composed of
D) two nested stainless steel canisters welded to two
E) stainless steel lids surrounding an
F) internal shield (usually uranium metal or a tungsten alloy) that protects a
G) cylinder of radioactive source material, often but not always cobalt-60. The diameter of the "source" is 30mm.