Radiation Radiation Radiation is the emission or transmission

Radiation

Radiation • Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium • Ionizing Radiation: It is the radiation that has ability to penetrate tissues and deposit its energy within them alpha rays, beta rays, xrays • Non-Ionizing Radiation: It has not sufficient energy to ionize matter like UV, Visible light

Sources of radiation Natural(Background) Artificial • Cosmic rays • Environmental • Internal body • Medical (x-rays) • Agricultural • Industries • Defense • Miscellaneous

Natural Sources • Cosmic rays: Originate in outer space • Environmental: It can be from terrestrial source like uranium, radium, thorium present in rocks and buildings • Internal from carbon-14 radioactive isotope present in living matter • These are “Background radiation”

Radium and Radon Hazards • These are important contributors to environmental radioactivity • Radon is 2% contributor of all cancer related deaths in Europe • Well & rain water can be very rich in radon • Epidemiological evidence shows a clear link between lung cancer and high concentrations of radon (EPA, 2003) • Radon concentration is usually measured in the atmosphere in Becquerel per cubic meter (Bq/m 3)

Artificial Sources (Medical) • Radiation have saved thousands of lives through the detection and treatment of conditions ranging from hyperthyroidism to bone cancer • Computed tomography (CT) scanners • Nuclear medicines (radiotracers)

Artificial sources (Agriculture) • Radioisotopes were used for producing high yielding crop seeds to increase the agricultural yield • Radiations from certain radioisotopes were also used for killing insects which damage the food grains

Artificial Sources (Daily routine) • Nonstick cookware is treated with gamma rays to keep food from sticking to the metal surface • Reflective signs that have been treated with radioactive tritium and phosphorescent paint • Television, mobiles, luminous watches

Artificial Sources (Defense) • • • At air ports use of cabinet x-ray system Nuclear weapons (Fission Bombs) Thermonuclear weapons Nuclear fall outs or nuclear accidents Chernobyl disaster in USSR 1986 Fukushima disaster in Japan 2011

Units of Radiation • Radiation equivalent man(Rem): It shows biological impact • Absorbed radiation dose (Rad): It is unit of absorbed dose per gm of tissue • Sievert (Sv): unit of absorbed radiation dose. Mostly in milli and micron

Some other units • Relative Biological Effectiveness (RBE): is the ratio of biological effectiveness of one type of ionizing radiation relative to another • Bacquerel

Immediate Effects • Radiation Sickness • Acute radiation syndrome Ø Alopecia Ø Removal of sub-cutaneous fat Ø Dark complexion Ø Softening of muscles

Delayed Effects • • • Leukemia Carcinogenesis Fetal development abnormalities Shortening of life Teratogenesis

Half Life? ?

Why it is a Public Health issue? ?

Radiation Dose • The individual dose limit for radiation workers averaged over 5 years is 100 m. Sv, and • For members of the general public, is 1 m. Sv per year.

Protection Measures • According to International Commission on Radiological Protection (ICRP): Ø Limit time for exposure Ø Reduce distance Ø Use of protective shields Ø Avoid unnecessary x-rays Ø Spend time in open atmosphere Ø Radiation dosimeters

Radioactive wastes • Type A: The radioactive waste from laboratory and academic institutions and decay in almost 100 years • Type B: Medium radioactive material from nuclear plants and retain decaying activity for almost 300 years • Type C: High level radioactive waste from nuclear plants and accidents and remained as it is for >300 years

Methods of Radioactive Wastes Disposal • • Reprocessing and energy reclamation Cooling and solidification Deep thick concrete trench disposal Geological isolation in mines or deserts

Reference: • International atomic energy agency (IAEA)