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, x-rays Non-Ionizing Radiation: It has not sufficient energy to ionize matter like UV, Visible light

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

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/m3)

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 Alopecia Removal of sub-cutaneous fat Dark complexion 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 mSv, and For members of the general public, is 1 mSv per year.

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