From: Jacinta
Date: 9/21/2000
Time: 11:58:42 AM
Remote Name: 10.4.7.155
Radioisotopes are isotopes that are unstable. They undergo spontaneous conversions to a stable form as it emits subatomic particles (alpha, beta or gamma). Each radioisotopes has a half-life which is the time required for exactly one half of the atoms to undergo radioactive decay. Alpha particles are the least harmful due to the fact that the range in air are only a few centimeters, therefore making it impossible to penetrate the skin. Alpha particles cannot however be inhaled because internally they are highly toxic. Beta particles are the more harmful than alpha particles. They are electrons ejected from the nucleus upon the spontaneous transformation of a neutron into a proton. Beta particles if interacting with matter can result in secondary x-ray, excitation and ionization. Gamma rays are the most harmful because they are the most penetrating of the ionizing radiations. A gamma ray is a photon “packet” of electromagnetic radiation that arises in the nucleus. Each radioisotopes has a half-life which is the time required for exactly one half of the atoms to undergo radioactive decay. Radioisotopes are very useful in biochemical reactions and pathways. For example, in medicine: 1) 60Cobalt is used as a radiation source to arrest development of cancer. 2) 131Iodine is used in locating brain tumors, measuring cardiac output, determining liver and thyroid activity. 3) 14Carbon is used in studying abnormalities of metabolism that underlie diabetes, gout, and anemia. 4) 238Plutonium is used in cardiac pacemakers and spacecraft (the heat produced in the decay of the radioactive isotope is converted into electricity by means of thermoelectric junction circuits or related devices.
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