BASIC OF RADIATION; ORIGIN AND UNITS

INAYA MEDICAL COLLEGE (IMC) RAD 243 - LECTURE 2 BASIC OF RADIATION; ORIGIN AND UNITS DR. MOHAMMED MOSTAFA EMAM

LECTURES & CLASS ACTIVITIES https://inayacollegedrmohammedemam.wordpress.com/ Password: drmohammedemam 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 2

Outline Natural & Man-Made Background Sources of Radiation Fundamentals 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 3

Outline Approximately 5,000 natural and artificial radioisotopes have been identified 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 4

Solar Radiation EARTH HAS MANY RADIOACTIVE SOURCES Nuclear Medicine X-Rays Cosmic Rays Consumer Products Radon Radioactive Waste Terrestrial Radiation Each Other Food & Drink Nuclear Power 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 5

Radiation: energy in motion REMEMBER Definitions Radioactivity: spontaneous emission of radiation from the nucleus of an unstable atom Isotope: atoms with the same number of protons, but different number of neutrons Radioisotope: unstable isotope of an element that decays or disintegrates spontaneously, emitting radiation. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 6

REMEMBER Unstable atoms differ from stable atoms because they have an excess of energy or mass or both. Unstable atoms are known as radioactive atoms. E.g. Carbon 14, Uranium 238 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 7

REMEMBER Types of Radiation Non-Ionizing Radiation: Radiation that does not have sufficient energy to dislodge orbital electrons. Examples of non-ionizing radiation: microwaves, ultraviolet light, lasers, radio waves, infrared light, and radar. Ionizing Radiation: Radiation that has sufficient energy to dislodge orbital electrons. Examples of ionizing radiation: alpha particles, beta particles, neutrons, gamma rays, and x-rays. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 8

Solar Radiation EARTH HAS MANY RADIOACTIVE SOURCES Nuclear Medicine X-Rays Cosmic Rays Consumer Products Radon Radioactive Waste Terrestrial Radiation Each Other Food & Drink Nuclear Power 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 9

Terrestrial Radiation Greatest contributor is 226 Ra (Radium) with significant levels also from 238 U, 232 Th, and 40 K. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 10

Terrestrial Radiation Greatest contributor is 226 Ra (Radium) with significant levels also from 238 U, 232 Th, and 40 K. - Common radionuclides created during formation of earth: Radioactive Potassium (K-40) Radioactive Rubidium (Rb-87) 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 11

Uranium series Beginning with naturally occurring uranium-238, this series includes the following elements: 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 12

Uranium series Beginning with naturally occurring uranium-238, this series includes the following elements: 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 13

Uranium series Beginning with naturally occurring uranium-238, this series includes the following elements: astatine, bismuth, lead, polonium, protactinium, radium, radon, thallium, and thorium. The series terminates with lead-206. The total energy released from uranium-238 to lead-206, is 51.7 MeV. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 14

Measuring Radiation There are four different but interrelated units for measuring radioactivity, exposure, absorbed dose, and dose equivalent. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 15

Common Units Radioactivity Exposure Absorbed Dose Dose Equivalent 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 16

Common Units Radioactivity Exposure Absorbed Dose Dose Equivalent 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 17

Radioactivity refers to the amount of ionizing radiation released by a material. The units of measure for radioactivity are the curie (Ci) and Becquerel (Bq). 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 18

Radioactivity Units Rate of Decay / Potential to Decay The curie (symbol Ci); It is a non-si unit of radioactivity = 3.7 X 10 10 Bq. Becquerel (Bq) = 1 disintegration/second (dps). 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 19

Common Units Radioactivity Exposure Absorbed Dose Dose Equivalent 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 20

Exposure Roentgens (R); Charge produced in air from ionization by gamma and x-rays. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 21

Exposure Exposure describes the amount of radiation traveling through the air. Many radiation monitors measure exposure. Exposure unit is the Roentgen (R). 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 22

Common Units Radioactivity Exposure Absorbed Dose Dose Equivalent 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 23

Roentgen Absorbed Dose rad = 1/100 Gray (Gy) Energy deposited/ delivered by any form of ionizing radiation in a unit mass of material; Roentgen Absorbed Dose (rad) 1 rad = 1/100 Gy 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 24

Absorbed Dose Absorbed dose describes the amount of radiation absorbed by an object or person. The units for absorbed dose are the radiation absorbed dose Gray (Gy) and (rad). 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 25

Common Units Radioactivity Exposure Absorbed Dose Dose Equivalent 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 26

Dose Equivalent rem; roentgen equivalent in man Dose equivalent (or effective dose) combines the amount of radiation absorbed and the medical effects of that type of radiation. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 27

Dose Equivalent rem; roentgen equivalent in man Dose equivalent (or effective dose) combines the amount of radiation absorbed and the medical effects of that type of radiation. Units for dose equivalent are the roentgen equivalent man (rem) and Sievert (Sv). 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 28

Dose Equivalent Millirem (mrem) A rem is a large dose of radiation, so the millirem (mrem), which is 1/1000 of a rem, is often used for quantifying and measuring the dose around us; such as the amount of radiation received from medical x-rays and background sources. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 29

Dose Equivalent Millirem (mrem) A rem is a large dose of radiation, so the millirem (mrem), which is 1/1000 of a rem, is often used for quantifying and measuring the dose around us; such as the amount of radiation received from medical x-rays and background sources. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 30

Dose Equivalent rem = Q * rad rem = 1/00 Sievert (Sv) Scale for equating relative hazards of various types of ionization in terms of equivalent risk Damage in tissue measured in rem (Roentgen Equivalent Man). Q:risk of biological injury rem = Q * rad 1 rem = 1/100 Sv 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 31

Why do we want to know it? Dosage and dosimetry are measured and reported in rems. All the Federal and State regulations are written in rems. The regulators must be placated with reports in rems. 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 32

Common Units Radioactivity (Ci) Exposure (R) Absorbed Dose (rad & Gy) Dose Equivalent (rem=q x rad & Sv ) 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 33

Note.. Note that a measure given in Ci tells the radioactivity of a substance, while a measure in rem (or mrem) tells the amount of energy that a radioactive source deposits in living tissue. For example, a person would receive a dose equivalent of 1 mrem from any one of the following activities: 3 days of living in Atlanta 2 days of living in Denver 1 year of watching television (on average) 1 year of wearing a watch with a luminous dial 1 coast-to-coast airline flight 1 year living next door to a normally operating nuclear power plant 16-Feb-15 DR. MOHAMMED MOSTAFA EMAM 34