Radium, cancer associated with

Around the beginning of this century, cancer and illness was associated with excessive use of X-rays. Watch dial painters got mouth cancer from radium in the paint. It soon was realized that radiation has health effects. The measures of energy deposition concepts introduced... 

Radium occurs only in association with uranium (Chapter 31) the observed ratio Ra/U is 1 mg per 3 kg, leading to a terrestrial abundance for Ra of 10 ppm. As uranium ores normally contain only a few hundred ppm of U, it follows that about 10 tonnes of ore must be processed for 1 mg Ra. The total amount of Ra available worldwide is of the order of a few kilograms, but its use in cancer therapy has been superseded by the use of other isotopes, and the... 

For both humans and laboratory animals, one cannot currently distinguish between a radiation-induced cancer and a spontaneously occurring cancer (i.e., from an unknown cause). Therefore, statistical methods are used to determine whether radiation exposure is associated with an increase in cancer in a given study population. There have been several epidemiological studies in which definite dose-response relationships have been established for radiation-induced cancers. The best studied populations include atomic bomb survivors, Tinea capitis irradiation patients, ankylosing spondylitis irradiation patients, radium dial painters, radium therapy radium-224 patients, Thorotrast patients, uranium miners, Chernobyl fallout victims, and Mayak plutonium facility workers. 

Responses of laboratory animals to chronic radium exposure have been studied extensively and are similar to human responses. The large amount of human exposure data available is probably most relevant. Potential symptoms of overexposure to radium include anemia, cataracts, fractured teeth, excess cavities, and cancer. Bone cancer is the most common cancer site associated with high-level radium exposure, but increased risks of liver and breast cancer have also been reported. 

The uranium decay series provides the most important isotopes of elements radium, radon, and polonium, which can be isolated in the processing of uranium minerals. Each ton of uranium is associated with 0.340 g of Ra. Freshly isolated Ra reaches radioactive equilibrium with its decay products to Pb in about two weeks (see Fig. 1.2). Many of these products emit energetic y-rays, which resulted in the use of Ra as a y-source in medical treatment of cancer (radiation therapy). However, the medical importance of radium has diminished greatly since the introduction of other radiation sources, and presently the largest use of radium is as small neutron sources (see Table 12.2). 

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