Training Module 2 – Version 1.1 For Internal Use Only ® Radiation 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Origin of Radiation and History Nature of Radiation Radiation and Life Radiation Detection and Safety 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Origin of Radiation and History Nature of Radiation Radiation and Life Radiation Detection and Safety 

Training Module 2 – Version 1.1 For Internal Use Only ® Origin of Radiation and History Sources of radiation doses (UK) 

Training Module 2 – Version 1.1 For Internal Use Only ® Cosmic radiation Origin of Radiation and History Radiation doses depending on where we are Background radiation in Europe 

Training Module 2 – Version 1.1 For Internal Use Only ® Origin of Radiation and History 1895 Wilhelm Roentgen discovered X-rays 1896 Henri Becquerel discovered natural radioactivity in uranium 1998 Marie and Pierre Curie identified elemental radium, thorium and polonium 1901 First recorded medical use of a radioactive substance (radium on TB lesion) 1918 Ernest Rutherford observed constituents of the atomic nucleus 1930 Lawrence and Livingstone constructed the first cyclotron 1934 Enrico Fermi produced artificial radioactivity 1942 First controlled uranium fission reaction 1945 Bombs dropped on Hiroshima and Nagasaki 1954 First industrial scale nuclear power reactor in Russia 1964 Hal Anger invented the gamma camera for radionuclide imaging 1972 First patients underwent CT scanning 1986 Chernobyl reactor incident 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Origin of Radiation and History Nature of Radiation Radiation and Life Radiation Detection and Safety 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Composition of matter  Matter is composed of molecules  Molecules are composed of atoms  Atoms are composed of subatomic particles 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Atom model atom electron (-) neutron proton (+) nucleus 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Standard atomic notation X A Z N atomic mass (Z+N) atomic number (number of protons) (number of neutrons) 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Stability of atoms depending on the proton/neutron ratio very unstable unstable stable Unstable atoms decay into stable atoms, emitting α-,β-,γ-radiation 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Radioactive decay Unstable atoms decay into stable atoms, emitting either α-,β- or γ-radiation radiation They are - what we call – radioactive! unstablestable 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Alpha decay nucleus (helium atom nucleus) Very large unstable atoms can transform themselves into smaller atoms by emitting alpha radiation 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Beta decay electron Too many neutrons result in a negatron decay Too many protons result in a positron decay positron 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Gamma decay If the ratio of neutron and protons is within a stable range, but the energy of the nucleus is greater than the resting level, the excess nuclear energy is emitted as a gamma ray. 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Gamma ray Gamma ray is a photon (energy) with a much higher energy than visible light.  Wavelength [m] low energy high energy

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Penetrating properties of radiation α β γ paper copper / perspex lead / concrete 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Bremsstrahlung (‘braking radiation’) β lead / perspex γ The intensity depends on the density of the material; the denser the material the more Bremsstrahlung. 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Half-life time (t ½ ) The half-life of a radioactive material is the time taken for an arbitrary sample to halve its original amount of activity 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Measurement of radioactivity The amount of any radionuclide may be expressed as the number of decays per unit time. The SI unit is Becquerel, but Curie is also still used. One Becquerel (Bq) is defined as 1 radioactive decay per second One Curie (Ci) is defined as 3.7x10 10 radioactive decays per second 1 Ci = 3.7x10 10 Bq = 3.7x10 4 MBq = 37 GBq (M=Mega; G=Giga) 1 Bq = 2.7x Ci = 27 pCi (p=pico) 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Measurement of radioactivity The amount of any radionuclide may be expressed as the number of decays per unit time. The SI unit is Becquerel, but Curie is also still used. One Becquerel (Bq) is defined as 1 radioactive decay per second One Curie (Ci) is defined as 3.7x10 10 radioactive decays per second  Describes the activity of the PRODUCT

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Measurement of absorbed dose The unit of absorbed radiation dose is the gray (Gy) named after L.H.Gray, one of the first radiobiologist. The absorbed dose is a measure of the energy imparted per unit mass of tissue. One Gray (Gy) is equivalent to an absorbed radiation energy of 1 joule per kilogram of tissue In the US the unit rad is still in use. 100 rads being equivalent to 1 Gy 

Training Module 2 – Version 1.1 For Internal Use Only ® One Gray (Gy) is equivalent to an absorbed radiation energy of 1 joule per kilogram of tissue Nature of Radiation Measurement of absorbed dose The unit of absorbed radiation dose is the gray (Gy) named after L.H.Gray, one of the first radiobiologist. The absorbed dose is a measure of the energy imparted per unit mass of tissue.  Describes the intensity of the TREATMENT

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Measurement of dose equivalent The dose equivalent is the unit of absorbed energy that takes into account the estimated biologic effect of the type of radiation that imparts the energy to the tissue. The SI unit is Sievert (Sv). The relative damage for each type of radiation is referred to as its quality factor (QF) dose in Sievert = dose in Gray x QF QF (alpha)=10-20, QF (protons, neutrons)=10, QF (beta, gamma)=1 

Training Module 2 – Version 1.1 For Internal Use Only ® Nature of Radiation Measurement of dose equivalent The dose equivalent is the unit of absorbed energy that takes into account the estimated biologic effect of the type of radiation that imparts the energy to the tissue. The SI unit is Sievert (Sv). The relative damage for each type of radiation is referred to as its quality factor (QF) dose in Sievert = dose in Gray x QF  Describes the amount of personal EXPOSURE

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Origin of Radiation and History Nature of Radiation Radiation and Life Radiation Detection and Safety 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation and Life The biological effects of radiation depend upon Type of radiation (α,β,γ) Amount of radiation (dose) Time of exposure 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation and Life α-radiation:0.04mm5Mev β-radiation:7mm1MeV γ-radiation:65cm1MeV skin muscle  Radiation penetration Radiation Distance Energy

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation and Life Radiation effect after short time exposure Less than 0.5 Svtemporary blood effects Sv10% Nausea and vomiting 4-5 Sv50% lethal Sv100% lethal 50 SvDeath within 1 week 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation and Life The sequence of events resulting in radiation damage Initial Interaction Ionization and excitation to seconds Chemical Damage Free radical production to seconds Biomolecular Damage Proteins and nucleic acid damage Seconds to hours Biological Damage Cell mutation, cell death and animal death Hours to decades 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation and Life Cellular effects All radiation injury results primarily from radiation induced chemical changes in one or more of the complex molecules (mainly DNA) which are present in living cells 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation and Life Radiosensitivity and cell cycle The greatest amount of damage occurs during the period of mitosis where one cell divides into two individual cells 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation and Life Tissue sensitivity Different organs of the body vary in their sensitivity to absorbed doses of radiation The most sensitive organs are generally those with the highest rate of cellular replication These are bone marrow, lung, thyroid, bone, gonads and female breast 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Origin of Radiation and History Nature of Radiation Radiation and Life Radiation Detection and Safety 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Detection and Safety Monitors used for detection of radioactivity pancake probe (α-, β- and γ-radiation) scintillation probe (β- and γ-radiation) high sensitivity monitor reading multiplier 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Detection and Safety Personal dosimetry electronic dosimeter thermo luminescent dose meter (TLD) film badge finger ring (TLD) Dose limits recommended by the ICRP (1991): Occupational:100mSv in 5 years, 50mSv maximum in any year Public:5mSv in any 5 consecutive years 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Detection and Safety Dose calibrator ionization chamber electrometer The exact amount of radioactivity can be assayed in a dose calibrator. A factor appropriate for the energy of the radionuclide is entered and the amount of radioactivity can be read directly. 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Detection and Safety Radiation protection The 3 methods of reducing external exposure relate to: Time of exposure (the less the better) Distance to the source (the more the better) Appropriate Shielding (the more the better) 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Origin of Radiation and History Nature of Radiation Radiation and Life Radiation Detection and Safety 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation α-,β-,γ-radiation and Bremsstrahlung radioactive decay and half-life time absorbed dose and dose equivalent biological effects of radiation principles of radiation protection What is most important to remember? 

Training Module 2 – Version 1.1 For Internal Use Only ® Radiation Further Readings A.C.Percins: Nuclear Medicine – Science and Safety 1995 R.A.Powsner & E.R.Powsner: Nuclear Medicine Physics 1998