CHAPTER 1 INTRODUCTION TO RADIOBIOLOGY HDR 112 RADIATION BIOLOGY AND RADIATION PROTECTION MR KAMARUL AMIN BIN ABDULLAH

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1 HDR 112 RADIATION BIOLOGY AND RADIATION PROTECTION CHAPTER 1 INTRODUCTION TO RADIOBIOLOGY PREPARED BY: MR KAMARUL AMIN BIN ABDULLAH SCHOOL OF MEDICAL IMAGING FACULTY OF HEALTH SCIENCE

2 LEARNING OUTCOMES At the end of the lesson, the student should be able to:- Explain the history of radiation injury. Describe the firstly discovered of radiation injury. Explain the types ionizing radiation. Slide 2 of 52

3 OUTLINES INTRODUCTION 1.1 Significant Discoveries 1.2 New Dangers Come with Discoveries 1.3 Meeting the Need for Radiation Protection 1.4 Ionization 1.5 Types or Products of Ionizing Radiation 1.6 References Slide 3 of 52

4 INTRODUCTION Since ancient times, philosophers and scientists have been interested in the basic building blocks of our physical universe. In fact the ancient Greeks were the first to believe that all matter in the universe must be made of tiny building blocks or atoms. Slide 4 of 52

5 INTRODUCTION Beginning with the earliest scholars of science throughout history and into this century, scientists have been driven to learn more about the atom and how to control it. Slide 5 of 52

6 1.1 Significant Discoveries It wasn't until the latter part of the 19th century that scientists truly began to make advances in the study of atomic structure and radiation. Slide 6 of 52

7 1.1 Significant Discoveries During the 1600s, Sir Isaac Newton had proven his theories on gravity. Marie and Pierre Curie had begun their studies in chemistry and physics, and Dmitri Mendeleev had introduced the periodic system of elements. Just before the turn of the century, Wilhelm Conrad Roentgen discovered the basic properties of X-Rays; the properties of ionizing radiation and the possibility of using radiation in medicine. Slide 7 of 52

8 1.1 Significant Discoveries Finally, in 1896, Henri Becquerel announced the discovery of radioactivity to the Academy of Sciences in Paris. By the early 1900s the study of radiation was a widely accepted scientific endeavor. Slide 8 of 52

9 1.2 New Dangers Come with Discoveries But, these discoveries did not come without a price. Scientists learned that radiation was not only a source of energy and medicine, it could also be a potential threat to human health if not handled properly. In fact, early pioneers in radiation research died from radiationinduced illnesses (too much exposure). Slide 9 of 52

10 1.2 New Dangers Come with Discoveries For instance, Thomas Edison's assistant died from a radiation-induced tumor as a result of too much x-ray exposure. As new uses for radioactive elements were discovered, potentially fatal incidents of overexposure increased. Slide 10 of 52

11 1.2 New Dangers Come with Discoveries Example 1: Radium Paint During World War I, radium paint (a mixture of radium and phosphor) was used on military aircraft instruments to make them glow in the dark so they would be more visible to pilots flying at night. Slide 11 of 52

12 1.2 New Dangers Come with Discoveries Example 2: Luminous Dial Painters After the war was over, the industry that supported this technology changed their business to paint glow-in-the-dark clocks and watch faces. The young women who were employed in this vocation would form a fine point on their paint brushes by pulling the freshly-dipped brushes between their lips before applying the paint onto the watch faces. Slide 12 of 52

13 1.2 New Dangers Come with Discoveries Slide 13 of 52

14 1.2 New Dangers Come with Discoveries Unknowingly, they were swallowing small amounts of radium and damaging their bodies. Over a two-year period, nine women who had worked as dial painters died of severe and unexplained anemia, accompanied by destructive lesions of the mouth and jawbones. A dentist who had treated one of these women finally made the connection between inflammation of the jawbone marrow, and the radium dial painting. Slide 14 of 52

15 1.2 New Dangers Come with Discoveries Slide 15 of 52

16 1.2 New Dangers Come with Discoveries Example 3: Radium Miners Radium is chemically similar to calcium. Incorporated to bone tissue. Caused: osteoporosis, osteogenic carcinoma, carcinoma of epithelial cells. Slide 16 of 52

17 1.2 New Dangers Come with Discoveries Example 4: Atomic Warfare Is a military conflict or political strategy in which nuclear weaponry is used to inflict damage on an opponent. Could have severe long-term effects, primarily from radiation release. Could last for decades, centuries, or even millennia after the initial attack. Only two nuclear weapons have been used in the course of warfare, both by the United States near the end of World War II. Slide 17 of 52

18 1.2 New Dangers Come with Discoveries Slide 18 of 52

19 1.2 New Dangers Come with Discoveries Example 5: Power Plant Accidents Nuclear power plants - they have various kinds of accidents have occurred, from the mundane to the catastrophic. E.g: Employees have mishaps and equipment breaks down. When accidents occur, they usually result in a minor release of radioactive steam or water. The incident at Chernobyl was the most extreme nuclear accident in history, resulting in deaths from radiation, destruction of the plant and widely-dispersed radioactivity. Slide 19 of 52

20 1.2 New Dangers Come with Discoveries The Three Mile Island nuclear power plant accident March 28, Slide 20 of 52

21 1.2 New Dangers Come with Discoveries Year Events 1895 Discovery of x- ray 1896 a) Becquerel discover radiations emitted by uranium compounds. b) First biological effects e.g.: skin burns, epilation Discoveries of alpha-ray and beta-ray Law of Bergonie and Tribondeau Leukemia in five radiation workers reported British Roentgen Society introduces proposals for radiation protection. Slide 21 of 52

22 1.2 New Dangers Come with Discoveries Year Events First observation of mutations by x- rays in Drosophila. First international recommendations on radiation protection First survival curve for bacteria Atomic bomb in Hiroshima & Nagasaki Hereditary effects of radiation in mice reported First in- vitro radiation survival curve for mammalian cells Chernobyl nuclear reactor meltdown. Slide 22 of 52

23 1.3 Meeting the Need for Radiation Protection By 1915, the British Roentgen Society had adopted a resolution to protect people from overexposure to X-rays. This was probably the first organized effort at Radiation Protection. Slide 23 of 52

24 1.3 Meeting the Need for Radiation Protection By 1922, American organizations had adopted the British protection rules. Awareness and education grew, and throughout the 1920s and 30s, more guidelines were developed and various organizations were formed to address radiation protection in the United States and overseas. Slide 24 of 52

25 1.3 Meeting the Need for Radiation Protection Radiation protection was primarily a non-governmental function until the late 1940s. After World War II, the development of the atomic bomb, and nuclear reactors caused the federal government to establish policies dealing with human exposure to radiation. In 1959, the Federal Radiation Council was established. Slide 25 of 52

26 1.3 Meeting the Need for Radiation Protection The FDR Council was responsible for three things: 1. advising the President of the United States on radiological issues that affected public health 2. providing guidance to all federal agencies in setting radiation protection standards 3. working with the States on radiation issues. Slide 26 of 52

27 1.3 Meeting the Need for Radiation Protection In 1970, Congress created the Environmental Protection Agency (EPA) and radiation protection became a part of EPA's responsibility. Today, EPA's Radiation Protection Division (RPD) is responsible for protecting the public's health and the environment from undue exposure to radiation. This is accomplished by setting safety standards and guidelines. Now, organizations that deal with ionizing radiation must meet these standards to comply with the law. Slide 27 of 52

28 1.3 Meeting the Need for Radiation Protection The Radiation Protection Program is responsible for other protection activities too. For example, there is a team of experts that respond to emergencies involving radioactivity. There is also a laboratory that monitors the environment to determine how much radiation is in the air. Slide 28 of 52

29 1.3 Meeting the Need for Radiation Protection In Malaysia, there is MARPA (Malaysian Radiation Protection Association/Persatuan Perlindungan Sinaran Malaysia) is a nongovernmental organization that was established on 15 September Visit for more info. Slide 29 of 52

30 1.3 Meeting the Need for Radiation Protection It represents a pool of professionals of highest skill in radiation protection and safety. MARPA can be considered a national asset and a resource for experts and specialists in radiation protection and safety. Slide 30 of 52

31 1.4 Ionization Ionizing radiation is produced by unstable atoms. Unstable atoms differ from stable atoms because they have an excess of energy or mass or both. Unstable atoms are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation. Slide 31 of 52

32 1.5 Types or Products of Ionizing Radiation 1. Alpha particles 2. Beta particles 3. Gamma rays (or photons) 4. X-Rays (or photons) 5. Neutrons Slide 32 of 52

33 1.5 Types or Products of Ionizing Radiation neutron or X-ray Slide 33 of 52

34 1.5 Types of Ionizing Radiation: Alpha Particles Alpha Particles: 2 neutrons and 2 protons They travel short distances, have large mass Only a hazard when inhaled Slide 34 of 52

35 1.5 Types of Ionizing Radiation: Beta Particles Beta Particles: Electrons or positrons having small mass and variable energy. Electrons form when a neutron transforms into a proton and/or an electron. Slide 35 of 52

36 1.5 Types of Ionizing Radiation: Gamma Rays Gamma Rays (or photons): Result when the nucleus releases energy, usually after an alpha, beta or positron transition. Slide 36 of 52

37 1.5 Types of Ionizing Radiation: X-rays X-Rays: Occur whenever an inner shell orbital electron is removed and rearrangement of the atomic electrons results with the release of the elements characteristic X-Ray energy. Slide 37 of 52

38 1.5 Types of Ionizing Radiation: Neutrons Neutrons are usually produced when a nuclear transformation is induced (that is, is made to happen, rather than through occurring naturally), for example by taking an atomic nucleus and firing another nuclear particle at it, or when radioactive fission occurs (the breaking up of a large unstable nucleus into two roughly equal nuclei, each around half the size of the original and with the liberation of considerable amounts of energy). Most neutron sources occur in the laboratory (or nuclear reactor) under special conditions Slide 38 of 52

39 Nuclear fission is fundamental to the operation of many types of nuclear reactor. During the fission process, large amount of energy are released from the nucleus that undergoes fission, and this energy can be used to provide electrical power by heating water. Slide 39 of 52

40 1.6 References Bushong, S.C. (2008). Radiologic science for technologist. 9 th ed. Mosby Elsevier Slide 40 of 52