Joe Armstrong, age 15, of E1 Paso, Tex., for his question:

HOW DOES A PERSON GET RADIATION SICKNESS?

Radiation sickness is the illness that follows a person's exposure to damaging amounts of certain types of radiations. These raadiations come not only from atomic explosions but also from radioisotopes, atom smashers or even certain X ray machines.

Ionization from the radiations cause changes in the atoms of living tissue. Thus often the function of vital substances is lost with radiation sickness.

Some cells are more easily injured than others, but scientists do not know why. Most sensitive are cells of the blood forming organs (bone marrow), the lining of the stomach and intestines, the skin and the sex glands. Most resistant to radiation are the cells of the brain and muscles.

There are several different kinds of radiation sickness, each differing from the others in the amount of radiation received by the individual.

Doctors have found no treatment for radiation sickness, other than transfusions and antibiotics.