Exposure to ionizing radiation is considered to be dangerous for humans. The rays or particles can do damage to human tissue to an extent that is dose dependent: the more radiation, the more damage. One theory on the relationship between absorbed radiation dose and the probability of health effects is that it is linear without threshold, which would mean that there is a possible risk of health effects with any dose, however small. While there may indeed be no absolutely safe dose, but there are dosages that are considered acceptable for practical purposes and unlikely to produce health effects. The risk of exposure is also dependent to a certain degree on the length of time over which the exposure occurred. The body can tolerate small doses that add up over time better than the same exposure all at once.
All humans are exposed to some radiation simply by living on earth. This naturally occurring or “background” radiation comes from the radioactive decay of naturally occurring radioactive elements in the earth’s crust. In addition to this, other sources of radiation are part of the course of everyday life: dental or medical X rays, microwave radiation, luminous watch dials, color televisions, cosmic radiation, smoke alarms, exit signs; a variety of sources of exposure to extremely small doses which add up slowly over time since dosage of radiation is cumulative over a lifetime. When an exposure occurs over an extended period of time, it is referred to as “Chronic Exposure”. All of us are chronically exposed to radiation naturally and in the course of daily life. Persons working in the nuclear industry or utilizing a radiation source in the course of their work receive additional exposure. Standards have been set to protect such workers from dangerous dosages of radiation. However, these standards tend to change (lower) as more is learned about the effects of radiation on the human body. A principal exists in the field of radiation protection which is referred to by the acronym “ALARA”, which stands for As Low As Reasonably Achievable.
Under this principle all exposures are kept to standardized minimum. In addition, the industry is required to take measures to reduce exposure if they can do so at a reasonable cost. In order to monitor occupational exposures, the worker wears a film badge or “dosimeter” to measure the amount of radiation they are exposed to. Records are kept of the readings so that cumulative dose tabulation can be kept. Recent recommendations have resulted in a lowering of the maximum acceptable exposure. As indicated by the Uranium Institute, “Dose limits are considered to be the maximum acceptable exposure for an individual but they do not represent an acceptable level of exposure for a large number of individuals, or a level of exposure to which an individual can be repeatedly exposed”. There are numerous international, federal and private organizations which disagree on how much exposure is “unhealthy”.
Some feel that any dose of ionizing radiation, no matter how small, has the potential to do cellular damage. Others believe that there is not enough evidence to support such claims. One common agreement, however, is that there is no one standard physiological reaction to specific levels of radiation. Some people are able to tolerate certain types of radiation better than others. Persons exposed to the same sources of “acute” (short-term) radiation can end up later in life with very different physiological results. Ultimately, it is important for those concerned to investigate all current avenues of research.