How radiation affects your body?

Radiation Effects, effects observed when ionizing radiation strikes living tissue and damages the molecules of cellular matter. Cellular function may be temporarily or permanently impaired from the radiation, or the cell may be destroyed. The severity of the injury depends on the type of radiation, the absorbed dose, the rate at which the dose was absorbed, and the radiosensitivity of the tissues involved. The effects are the same, whether from a radiation source outside the body or from material within.

The biological effects of a large dose of radiation delivered rapidly differ greatly from those of the same dose delivered slowly. The effects of rapid delivery are due to cell death, and they become apparent within hours, days, or weeks. Protracted exposure is better tolerated because some of the damage is repaired while the exposure continues, even if the total dose is relatively high. If the dose is sufficient to cause acute clinical effects, however, repair is less likely and may be slow even if it does occur. Exposure to doses of radiation too low to destroy cells can induce cellular changes that may be detectable clinically only after some years.


II. Acute Effects


High whole-body doses of radiation produce a characteristic pattern of injury. Doses are measured in grays or rads, 1 gray being equal to the dose absorbed when one kilogram of matter absorbs one joule of ionizing radiation, and 100 rads being equal to 1 gray. Doses of more than 40 grays severely damage the human vascular system, causing cerebral edema, which leads to profound shock and neurological disturbances; death occurs within 48 hours. Whole-body doses of 10 to 40 grays cause less severe vascular damage, but they lead to a loss of fluids and electrolytes into the intercellular spaces and the gastrointestinal tract; death occurs within ten days as a result of fluid and electrolyte imbalance, severe bone-marrow damage, and terminal infection. Absorbed doses of 1.5 to 10 grays cause destruction of human bone marrow, leading to infection and hemorrhage; death, if it occurs, can be expected about four to five weeks after exposure. Currently only the effects of these lower doses can be treated effectively; but if untreated, half the persons receiving as little as 3 to 3.25 grays to the bone marrow will die.

Exposure of small areas of the body—the most frequent kind of radiation accident—leads to localized tissue damage. Damage to the blood vessels in exposed areas causes disturbed organ function and, at higher doses, necrosis (localized tissue death) and gangrene.