Objectives Define radiobiology Discuss the history of radiobiology Name the leaders/pioneers of radiobiology and their contributions to the field Define terms related to the measurement of radiation Identify regulations related to the field of radiobiology Provide for the audience five questions and answers List the references used for the presentation Wrap up the presentation with a sound conclusion
Definition of Radiobiology The branch of science concerned with the methods of interaction and the effects of ionizing radiation on living system It’s a combination of biology, physics, and epidemiology Radiation biology encompasses the studies of effects of external radiations and isotope distribution in the environment, and their effects when present as contaminants in the environment and in the body
Discuss the history of Radiobiology A series of incidents spark the birth of nuclear radiology Discovery of x-rays in 1895 by W.C. Roentgen Discovery of radioactivity by Henri Becquerel in 1896 Discovery of radium by Pierre and Marie curie in 1898
History of Radiobiology (cont) 1906, first x-ray fatality in the U.S 1900s through late 1950s and 1960s: we have witnessed the explosion of the field of radiobiology due the observations of other pioneers such as : Becquerel, the Curies,Bergonie and Tribondeau, Ancel and Vitemberger, and many others notable radiologists.
Identify leaders in the field and their contributions to Research Wilhelm Conrad Roentgen discovered x-ray in 1895 Henri Becquerel observed rays by uranium-containing substance in 1896----Marie curie call it radioactivity Discovery of radium by Pierre and Marie Curie in 1898 J. Bergonie and L. Tribondeau observed the effects of radiation on cells, tissues and organs, metabolic activity, proliferation and growth rate—therefore compare to a child or mature adult, the fetus is most radiosensitive
Henry Becquerel Marie Curie & Pierre Curie Wilhelm Conrad Roentgen J. Bergonie and L. Tribondeau
Leaders & Contributions (cont) Ancel and Vitember determined: radiation damage is determined by the amount of biological stress receives the conditions the cell is exposed to before and after radiation Muller made the discovery of radiation’s role in mutation—mutagenesis Puck and Marcus made the discovery of reproductive failure while exposing humans uterine cervix cells to various dose of radiation (1956) The oxygen effects during the 1940s and 1950s, because it increases the killing effect of a given dose of radiation (free radicals)—thus oxygen, a radiosensitizer
Unit Used to Measure Radiation Quantity The ROENTGEN (R) is a measure of the ionization of air that is created by x- and gamma-radiation below 3 MeV. It is the unit of measurement that created the basic tool for defining standards of protection for personnel. 1937 was internationally adopted and is defined as: 1 R = 2.58x10-4 coulomb/kg air
Units Used for Measuring Radioactivity Radioactivity or the strength of radioactivity source is measured in Bequerels (Bq) 1Bq = 1 event of radiation emission per second. Common multiples of the Bq unit are: kBq (kilobequerel), MBq (megabequerel), GBq (gigabequerel).
Units Used for Measuring Radioactivity 1 kBq = 1000 Bq, 1 MBq = 1000kBq, and 1 GBq= 1000MBq 1Bq = 1 desintegration per second An old but still popular unit of measuring radioactivity is the curie 1 Ci = 37 GBq = 37000 MBq
Units Used for Measuring Radioactivity Common multiples of the curie unit are: Ci (curie), mCi (millicurie) and µCi (microcurie) 1Ci = 1000mCi ; 1mCi = 1000µCi 1 Ci = 3.70 x 1010 Bq
Units used to measure Absorbed Most common unit used is the RAD 1 Rad (radiation absorbed dose) = the amount of radiation that deposits energy at the rate of 1.00 x 10-2 J per kilogram in an absorbing material Using the SI unit of measurement, the GRAY (Gy) is used. 1 rad = 0.01 Gy 1 Gy = 100 rad
Units Used to Measure Occupational Exposure Most common unit used is the REM 1 rem represents the amount of radiation received by personnel. Using the SI unit of measurement, the SIEVERT (Sv) is used. 1 rem = 0.01 Sv 1 Sv = 100 rem
Units Used to Measure Radiation Although the National Council on Radiation Protection and Measurement adopted the use of SI units in 1985, traditional units are still in use.
Nuclear Regulatory Commission 10CFDR20 States: Subpart B- Radiation Protection Programs • Each licensee shall develop, document, and implement a radiation protection program commensurate with the scope and extent of licensed activities and sufficient to ensure compliance with the provisions of this part. • (b) The licensee must use, controls based upon sound radiation protection principles to achieve occupational doses and doses to members of the public that are as low as is reasonably achievable (ALARA). • (c) The licensee shall review the radiation protection program content and implementation at least once a year.
NCR 10CFDR20 (cont) Subpart C-- Occupational Dose Limits (a) The licensee shall control the occupational dose to individual adults,to the following dose limits. (1) An annual limit of-- (i) The total effective dose equivalent being equal to 5 rems (0.05 Sv); or (ii) The sum of the deep-dose equivalent and the committed dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 50 rems (0.5 Sv). (2) The annual limits to the lens of the eye, to the skin of the whole body, and to the skin of the extremities, which are: (i) A lens dose equivalent of 15 rems (0.15 Sv), and (ii) A shallow-dose equivalent of 50 rem (0.5 Sv) to the skin of the whole body or to the skin of any extremity. (b) Doses received in excess of the annual limits, including doses received during accidents, emergencies, and planned special exposures, must be subtracted from the limits for planned special exposures that the individual may receive during the current year.
NCR 10CFDR20 (cont) Subpart D- Radiation Dose Limits For Individual Members of the Public • The total effective dose equivalent to individual members of the public from the licensed operation does not exceed 0.1 rem (1 mSv) in a year, exclusive of the dose contributions from background radiation, from any administration the individual has received, from exposure to individuals administered radioactive material • For visitors of patients that cannot be released: a radiation no greater than 0.1 rem (1mSv).
Conclusion Discovery of x-ray by Roentgen—thus the founding father of radiobiology Law of Bergonie and Tribondeau Muller discovery of mutagenesis The roentgen, a unit of radiation quantity Rad measures radiation dose absorbed Rem the unit of dose equivalent or occupational exposure Regulation ( NRC 10CFR20)
Questions 1.Who is regarded as the father of Radiobiology? 2.What is epilation? 3.Who discovers that ionizing radiation produced mutations, and what year? 4.According to the NRC, what is the annual dose limit for the lens of the eye? 5.What is the difference between direct and indirect effects?
Answers 1. Wilhelm Conrad Roentgen 2. radiation induced hair loss 3. H. Muller, 1927 4. 150 MsV (15 rem/year) 5. direct effects—original ionization occurs directly on target indirect effects—original ionization occurs in water, and transfers ionization to target molecule
Work cited Essentials of Radiation Biology and Protection, Steve Forshier, Med,RT www.wikipedia.org www.yahoo.com www.google.com