Gamma radiation emitters

Table 1 Physical Characteristics of Some Commonly Used Gamma Radiation Emitters...

Using the miner data for this purpose may be overestimating the risk due to indoor exposure, since it includes risks from simultaneous exposure to external gamma radiation, long lived alpha emitters. This effect, however, may be outweighed by the fact... 

Most water systems are required to monitor for radioactivity and certain radionuclides, and to meet maximum contaminant levels (MCLs) for these contaminants, to comply with the Safe Drinking Water Act (SDWA). Currently, USEPA requires drinking water to meet MCLs for beta/photon emitters (includes gamma radiation), alpha particles, combined radium 226/228, and uranium. However, this monitoring is required only at entry points into the system. In addition, after the initial sampling requirements, only one sample is required every three to nine years, depending on the contaminant type and the initial concentrations. 

Radioisotopes are also used in radiation therapy to treat cancer. The goal in radiation therapy is to kill malignant cells, while protecting healthy tissue from radiation effects. Radioisotopes such as yttrium-90, a beta emitter, may be placed directly in the tumor. Alternatively, the diseased tissue may be subjected to beams of gamma radiation. Cobalt-60 used in radiation therapy is prepared by a series of transmutations ... 

The shelf life of fresh strawberries and other perishables is markedly increased when the food is subjected to gamma rays from a radioactive source. The strawberries on the right were treated with gamma radiation, which kills the microorganisms that normally lead to spoilage. The food is only a receiver of radiation and is in no way transformed to an emitter of radiation, as can be confirmed with a radiation detector. 

However, radiation exposure is low if only y rays are emitted, as in the case of isomeric transition (IT) or electron capture (e). Gamma-ray emitters are easily measurable from outside, and y-ray energies in the range between about 50 and 500 keV are most favourable with respect to penetration through tissues and counting efficiency. 

Nickel-63. With a radiological half-life of 96 years, nickel-63 is a beta emitter with a short decay chain and no gamma radiation. Nickel-63 is found in the chemical agent monitors (CAM). The beta radiation from Nickel-63 will not penetrate the dead layer of skin. Efforts should be taken to prevent ingestion, inhalation, or absorption through broken skin. 

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