Radiation shielding is the process of limiting the penetration of radiation into the environment, by blocking with a barrier made of impermeable material. This protective barrier is usually formed of a material with high density, for example lead that absorbs the radiation.
Radiation sources are self-shielded with absorbing material incorporated into the equipment, adjacent to the source to reduce stray radiation to the surrounding area below dose limits.
Rooms with x-ray or other radiation equipment are additionally shielded with lead-lined walls to reduce the radiation exposure to humans within the facility. The amount of shielding required to protect against different kinds of radiation depends on how much energy they have. The shielding calculations are based on the half value layer of the primary radiation beam. Sufficient half value layers of shielding are calculated to reduce the radiation exposure outside the room to reasonable levels.
Personal shielding requirements depending on the type of radiation:
See also Radiation Safety.

Radiation safety concerns the safe use of ionizing radiation. The radiation exposure has to be controlled to protect people and the environment from unnecessary exposure and the damaging effect to the health. Legal regulations require that radiation exposure (individual radiation exposure as well as collective dose) must be kept as low as reasonably achievable.
The electromagnetic spectrum includes x-rays, gamma rays, ultraviolet radiation, visible light, infrared radiation, and radio waves. Additionally, there are several types of particulate radiation e.g., alpha and beta particles. All types of radiation are used in a wide range of medicine, industry, research and communication. Radiation risks can occur due to either long-term low level exposure or short-term high level exposure. A well-functioning dosimetry program is essential for a safe use and for compliance with federal and state regulations.

Three basic rules have to be observed for a safe use of ionizing radiation.

See also Inverse Square Law, Administrative Dose Guidelines and Annual Dose Limit.

Henri Becquerel demonstrated beta particles in 1900. Identical with electrons is there negative charge at -1. Their mass is 549 millionths of one AMU, 1/2000 of the mass of a proton or neutron. Beta particles consist of high energetic electrons emitted by radioactive nuclei or neutrons. By the process of beta decay, one of the neutrons in the nucleus is transformed into a proton and a new atom is formed which has one less neutron but one more proton in the core. Beta decay is accompanied by the emission of a positron (the antiparticle of the electron), a positive charged antineutrino. Beta particles have a greater range of penetration than alpha particles but less than gamma rays or x-rays. The name beta was coined by Rutherford in 1897. The traveling speed of beta particles depends on their energy. Because of their small mass and charge beta particles travel deep into tissues and cause cellular damage and possible cancer.

See also Radiation Shielding.

A broad beam describes a radiation shielding situation in which the beam impinging on a barrier surface is laterally extensive including scattered radiation.

(Scintillation Camera, Scintillation Gamma Camera, Gamma Scintillation Camera or Anger Gamma Camera) A gamma camera is an imaging device used in nuclear medicine to scan patients who have been injected, inhaled, or ingested with small amounts of radioactive materials emitting gamma rays. The gamma camera records the quantity and distribution of the radionuclide that is attracted to a specific organ or tissue of interest.
The first gamma camera was developed and introduced by Hal O. Anger in 1957/58. The structure hasn't changed by today. A gamma camera consists of:

Through this design the simultaneous registration of gamma ray photons is possible, the computer further allows dynamic imaging.

See also Pinhole, Elution, Center of Rotation, First Pass Scintigraphy, and Anger Hal Oscar.