The PET scatter phantom is an acceptance testing tool used to determine the imaging systems relative sensitivity to scatter radiation. It can be used to measure the effects of dead-time and the effects of random events generated at different levels of activity of the line source. The test phantom is a right circular cylinder composed of polyethylene. For ease of handling, it consists of 3 segments that are assembled together during testing. A hole is drilled parallel to the central axis of the cylinder, at a radial distance of 45 mm.