Biological Effect of Radiation

EFFECTS OF RADIATION Background Radiation is all around us. It is naturally present in our environment and has been since the birth of this planet. Consequently, life has evolved in an environment which has significant levels of ionizing radiation. It comes from outer space (cosmic), the ground (terrestrial), and even from within our own bodies. It is present in the air we breathe, the food we eat, the water we drink, and in the construction materials used to build our homes. Certain foods such as bananas and brazil nuts naturally contain higher levels of radiation than other foods.

Brick and stone homes have higher natural radiation levels than homes made of other building materials such as wood. Our nation’s Capitol, which is largely constructed of granite, contains higher levels of natural radiation than most homes. | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | How does radiation have an impact on health? Too much radiation, like too much of anything, is harmful. We know about this harm from research and from accidents, and from the effects of the two atomic bombs dropped on Japan in 1945.

The effects can range from mild gastrointestinal problems (such as nausea and vomiting) to changes in the blood, to damage to the central nervous system. Too little radiation, likewise, is also harmful. The world’s flora and fauna, including human beings, have grown up in a radioactive environment. We know from research in which organisms have been shielded from everyday radiation that their growth is stunted. We also know it from comparing populations that receive different levels of radiation because of their location.

Often, the populations receiving the most radiation are healthier and suffer fewer cancers. In between these extremes, it is usual to protect workers when they work in industries that use sources of radiation. Radioactive materials decay spontaneously to produce ionising radiation, which has the capacity to cause significant damage to the body’s internal chemistry, breaking the chemical bonds between the atoms and molecules that make up our tissues. Damage to the DNA of a cell is particularly important.

The body responds by trying to repair this damage, but at high doses it is too severe or widespread to make repair possible, leading to short-term acute health effects. There is also a danger of mistakes in the natural DNA repair process, which can lead in the long-term to cancer. Regions of the body that are most vulnerable to acute radiation damage include the cells lining the intestine and stomach, and the blood-cell producing cells in the bone marrow. The extent of the damage caused is dependent on how long people are exposed to radiation, and at what level.

These can include smaller head or brain size, poorly formed eyes, slow growth and severe learning difficulties. . | | COMMON RADIOISOTOPES AND THEIR USES Americium-241: Used in many smoke detectors for homes and businesses to measure levels of toxic lead in dried paint samples, to ensure uniform thickness in rolling processes like steel and paper production, and to help determine where oil wells should be drilled Cadmium-109: Used to analyze metal alloys for checking stock and sorting scrap Calcium-47: Aid to biomedical researchers studying the cell function and bone formation of mammals.

Californium-252: Used to measure the mineral content of coal ash and to measure the moisture of materials stored in silos Carbon-14: Used in research to ensure that potential new drugs are metabolized without forming harmful by-products. Cesium-137: Used to treat cancers; to calibrate the equipment used to measure correct patient dosages of radioactive pharmaceuticals; to measure and control the liquid flow in oil pipelines; to tell researchers whether oil wells are plugged by sand; and to ensure the right fill level for packages of food, drugs and other products. The products in these packages do not become radioactive. ) Chromium-51: Used in research in red blood cell survival studies. Cobalt-57: Used in nuclear medicine to help physicians interpret diagnostic scans of patients’ organs, and to diagnose pernicious anemia. Cobalt-60: Used to sterilize surgical instruments; to improve the safety and reliability of industrial fuel oil burners; and to preserve poultry, fruits and spices.

Copper-67: When injected with monoclonal antibodies into a cancer patient, helps the antibodies bind to and destroy the tumor Curium-244: Used in mining to analyze material excavated from pits and slurries from drilling operations. Iodine-123: Widely used to diagnose thyroid disorders. Iodine-129: Used to check some radioactivity counters in vitro diagnostic testing laboratories. Iodine-131: Used to diagnose and treat thyroid disorders Iridium-192: Used to test the integrity of pipeline welds, boilers and aircraft parts.

Iron-55: Used to analyze electroplating solutions. Krypton-85: Used in indicator lights in appliances like clothes washers and dryers, stereos and coffeemakers; to gauge the thickness of thin plastics, sheet metal, rubber, textiles and paper; and to measure dust and pollutant levels. Nickel-63: Used to detect explosives and as voltage regulators and current surge protectors in electronic devices Phosphorus-32: Used in molecular biology IN MEDICINE

Radioisotopes have found extensive use in diagnosis and therapy, and this has given rise to a rapidly growing field called nuclear medicine. These radioactive isotopes have proven particularly effective as tracers in certain diagnostic procedures. As radioisotopes are identical chemically with stable isotopes of the same element, they can take the place of the latter in physiological processes. Moreover, because of their radioactivity, they can be readily traced even in minute quantities with such detection devices as gamma-ray spectrometers and proportional counters.