💯 The Applications of Radioactive Isotopes Explained with Clear Examples. Watch this video to find! скачать в хорошем качестве

💯 The Applications of Radioactive Isotopes Explained with Clear Examples. Watch this video to find!

📢 Receive Comprehensive Mathematics Practice Papers Weekly for FREE 😊 Click this link to get: ▶️▶️▶️ https://iitutor.com/email-list/ ◀️◀️◀️ Nuclear medicine uses radiation for diagnostic purposes, therapy and sterilisation. A common diagnostic procedure in medicine involves the use of a tracer. A molecule is synthesised with a radioactive isotope that concentrates in the organ or region to be studied when introduced into the body. Detectors outside the body then use the radioactive emission to image the distribution of the radioactive isotope in the body. A commonly used isotope in medicine is technetium-99 (99Tc) , which readily combines with other atoms and has a half-life of 6 hours. A short half-life is important because the emission is only needed for imaging, and continued emissions after this time could cause harm to the patient. The difficulty with short half-life radio-isotopes is that they must be used very soon after they are produced. Gamma-ray emission from cobalt-60 (60Co) is also used to sterilise surgical dressings and surgical equipment, because viruses and bacteria are killed by high doses of radiation. Radioactivity is used in various industrial applications, most of which rely on the penetrating power and ionising properties of radiation. For example, gamma rays from cobalt-60 are used to examine welds for flaws in pipelines, ships, aircraft, etc. Gamma rays are also used to examine jet turbines for blockages and damage between regular engine services. The alpha-emitter americium-241 (241Am) is used as an ionisation source in smoke detectors, and the absorption of beta and gamma radiation is used to measure the thickness of paper, glass and plastic without touching the material during manufacture. The age of any object made from once living material can be determined by using radioactive carbon dating. When a plant dies it will contain the atmospheric ratio of 14C to 12C, which is 1.3 × 10–12. But as 14C is unstable with a half-life of 5730 years, the ratio of 14C to 12C will gradually decrease in the tissue. By measuring the ratio of 14C to 12C in a once living object, it is possible to determine the fraction of the initial 14C that decayed and calculate how long ago the object died. The use of a named isotope in medicine, agriculture and engineering Medicine • Using isotopes that emit positrons (positively charged beta particles), positron emission tomography (PET) produces maps of any body part. Carbon-11, which has a half-life of 20 minutes, is ingested by the patient. It is used to make glucose and is quickly absorbed into the bloodstream and travels throughout the body. Each positron emitted by C-11 combines with an electron in the body and produces two gamma rays travelling in opposite directions. A computer uses these gamma rays to build up a two- or three-dimensional map of the brain, heart, cancer, or whatever is being examined. • Iodine in our food collects in and is used by the thyroid gland, just below the larynx, to produce the hormone thyroxine, which helps control metabolic rate. iodine-131 can be used to monitor the functioning of the thyroid gland and help in the early detection of the disease called goitre. Agriculture • As tracers, radioactive carbon-14, hydrogen-3, phosphorus-32 or nitrogen-15 is tagged into compounds used by plants or animals and its path followed through the organism. In this way the chemical processes occurring in cells and tissues of organisms are studied. With increased knowledge of how organisms function, scientists can, amongst other things, manufacture fertilisers that work more efficiently, determine growing conditions that produce more product and determine the preferred diets of grazing animals. The path of pesticides through the food chain can also be studied. • Gamma rays from Co-60 are used to sterilise food products and seeds and extend their shelf life significantly. The radiation kills bacteria and viruses that would otherwise cause earlier decomposition of the substances. While these benefits are obvious, many people are opposed to this use on the basis that there may be undetected genetic modifications in the food or seed that could have long-term harmful effects. Engineering • Various radiation sources are used to measure and control the thickness of paper, glass, plastic or metal sheeting. They measure the radiation penetrating the substance and reaching the detector. If the radiation detected varies, the pressure on rollers changes automatically to achieve the desired thickness. • Americium-241 is used in smoke detectors. It emits alpha particles that ionise the air between two parallel plates with potential differences. If there is smoke in the air, some is attracted to the ionised air particles and change the current flow between the plates. This change in current sets off the alarm.