Living matter ionizing radiation, effect

X-rays, gamma, and cosmic rays are similar except for the fact that gamma and cosmic rays are natural. They ionize matter by photoelectric effect, Compton effect, and pair production (electron and positron). These radiations are of very high energy and therefore more penetrating. They cause injury to the tissues of the whole body. Therefore, they are more damaging to the living tissues. 

The effect of ionizing radiation on living matter depends on the quantity of energy absorbed and the extent of ionization in a given type of tissue. Radiation dose for the human body is measured in rem. 

The practical need for the assessment of induced mutations in man continues to grow. In part, the problem is created by the increasing intrusion of ionizing radiation into our lives, as reviewed in the reports of several national and international committees (National Academy of Sciences, 1956 Medical Research Council, 1956, 1960 United Nations, 1962, 1969). These reports present in detail the amount and sources of radiation reaching the public and the nature of the deleterious effects to be expected. It is sufficient to note here that the matter of possible genetic risks continues to be the central issue in discussions of permissible exposure to radiation, and new debates erupt almost yearly. 

We have discussed that ionization and ex tdfion are the two events that take place when radiation Interacts with matter. These events can also take place when radiation interacts with living tissues. This is (ffecfisefy the mechanism by vdilch radiation can have deleterious effects on life (see Boar 13.7. Although eveiy individual in the world is exposed to a small amount of radiation arising from natiunl and man-made sources, exposure to radiation is of more than mundane interest to a biologist who is exposed to radiations from tracer experiments which have become so common and useful. It is erefore useful for a biologist to know what are the tolerable radiation doses and to limit his/her exposure to those levels or levels even lower. 

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