X-ray Shielding
“X-radiation is a powerful and commonly used tool in modern society. Specifically, x-radiation is commonly used as a diagnostic tool in medical and industrial (non-destructive testing) fields. However, exposure to radiation can be damaging to human health. In order to protect users, patients and x-ray technicians, steps have been taken to limit their exposure to x-rays. For example, flexible x-radiation attenuating materials worn as protective aprons have been created in order to protect patients and technicians alike. In addition, x-radiation equipment has been designed to incorporate with shielding properties to reduce x-radiation exposure from the source generator.”
“In the field of x-ray equipment, shielding is required or mandated to reduce leakage of stray radiation to below specified maximum levels. Most shielded components of such equipment, such as x-ray tube housings, intensifier housings, collimators and filter devices, typically use a structural outer layer of metal for mechanical strength. This structural component is commonly machined, cast or forged aluminum, brass or steel. Since the aluminum, brass or steel is effectively radiolucent, the structural component is subsequently lined with a second layer of a material, such as lead, for radiation shielding. The lead shielding is typically held in place with an adhesive or by mechanical means, forming a multi-layer final structure with one layer providing strength and structure and the second layer providing x-radiation shielding.”
“Lead is often the material of choice used for x-radiation shielding in medical and industrial x-ray equipment because it is low in cost and readily available. The use of lead, however, poses significant manufacturing challenges as well as health and environmental hazards. There are two major disadvantages of using lead for radiation shielding: toxicity and the heavy weight of the material. The toxicity of lead has been shown to pose significant health risks to humans. Those adversely affected can include both those involved in processing and those using shielding materials and equipment. The environmental impact resulting from the disposal of products containing lead is also well established and a serious modern-day concern.”
Recent US Patents
9/20/2011
8,022,116
Lightweight rigid structural compositions with integral radiation shielding including lead-free structural compositions
Coppens, Lilley and Jones of Advanced Shielding Components, Pennsylvania, developed lightweight and rigid, lead-free integral radiation shielding structural materials consisting of two radiation shielding elements of antimony, bismuth, iodine, tungsten, tin, tantalum, erbium and barium, or theirs salts, compounds or alloys dispersed in a thermoplastic or thermoset resin that can shield x-rays having energies between 50 kVp and 200 kVp, preferably between 100 kVp and 160 kVp, more preferably