R250 Study Guide

Chapter 1

• What is the definition of matter, mass, and weight?

  • Matter: anything that occupies space and has mass

  • Mass: quantity of matter described by its energy equivalence

  • Weight: force on a mass that is caused by the acceleration of gravity

• What is the difference between element, atom, and molecule?

  • all matter is composed of building blocks called atoms

  • more then one atom together is called a molecule

  • an element are atoms that have the same atomic number and the sam chemical properties

• What is the definition of electromagnetic energy?

  • type of energy in x-rays, radiowaves, microwaves, and visible light

• What are the different types of energy and their definitions?

  • Potential Energy: the ability to do work by virtue of position (the potential to move)

  • Kinetic Energy: the energy of motion

  • Chemical Energy: the energy released by chemical reaction

  • Electrical Energy: work that can be done when an electron moves through an electric potential difference

  • Thermal Energy: the energy of motion at the molecular level

  • Nuclear Energy: energy contained within the nucleus of an atom

  • Electromagnetic Energy: type of energy in x-rays, radiowaves, microwaves and visible light

• What is the mass energy equivalence equation?

  • E=mc² (E=energy .. m=mass .. c=speed of light 3.0×10^8

• What does ionizing mean?

  • the removal of an orbital electron from the atom

• What are forms of natural environmental radiation?

  • Cosmic Rays: radiation from the sun and stars

  • Terrestrial Radiation: deposits of elements in the earth (uranium, throium, radionuclides)

  • Internally Deposited Radionuclides: mainly potassium are natural metabolites

  • Radon: largest source of natural radiation .. produced by the decay of uranium within the earth

• What are forms of man-made radiation?

  • diagnostic x-rays: largest source of man-made

  • nuclear power generation

  • research apps

  • industrial sources

  • consumer items

• Who discovered x-rays and when?

  • Wilhelm Roentgen on November 8th 1895

• When was the first x-ray fatality reported?

  • 1904

• What are the basic radiation protection methods?

  • protective apparel: lead aprons and lead gloves

  • gonadal shielding

  • protective barriers: control rooms(CT, Cath lab, IR, Surgery)

  • Filtration: metal filters filter out low energy x-rays

  • Collimation: reduces scatter and improves image contrast

• What are the different terminologies used for in radiologic science?

  • Air Kerma: kinetic energy released in matter .. Gya .. measured in J/kg .. SI unit of Air Kerma is mGya

  • Absorbed Dose: radiation absorbed per unit mass (different organs and tissue has different mass)

  • Effective Dose: how occupational radiation monitoring devices are measured .. SI unit is Sievert (Sv)

  • Radioactivity: quantity for radioactive material .. SI unit is Becquerel(Bq) .. have nothing to do with x-rays

Chapter 2

• What are the 3 basic measurable quantities?

  • length(meter m), mass(kilogram kg) and time(seconds s)

• What are Newton's laws of motion?

  • Inertia: a body will remain at rest or will continue to move with constant velocity in a straight line unless acted on by external force

  • Force: the force that acts on an object is equal to the mass of the object multiplied by the acceleration produced

  • Action/reaction: for every action, there is an equal and opposite reaction

• What is thermal energy?

  • transfer of heat by the emission of infrared radiation

• What are the three scales that have been developed to measure temperature?

  • fahrenheit, Celcius, Kelvin

• What is the definition of conduction, convection, and thermal radiation?

  • Conduction: the transfer of heat through direct contact between objects

  • Convection: Trasnfer of heat through the movement of a fluid

  • Thermal: transfer of hear by emission of infrared radiation

Chapter 3

• What did the Greeks think matter was composed of?

  • air, earth, fire, water

• Who developed the periodic table?

  • Dmitri Mendeleev

• How many elements have been identified?

  • 118

• What are the fundamental particles of an atom and their charges?

  • Electron(negative charge), proton(positive charge), neutron(neutrally charged)

• What is an atom mostly made up of?

  • mostly empty space

• What is the symbol for atomic mass and atomic number?

  • atomic mass = A

  • atomic mass number = Z

• What are the maximum electron distributions per shell

  • 98

• What is the maximum number of electrons an outer shell can contain in an atom?

  • 8

• What is the definition of centripetal force and centrifugal force?

  • centripetal force: “center seeking force” .. the force that keeps an electron in orbit

  • centrifugal force: the force that maintains distance from the nucleus

• What is the definition of isotopes, isobar, isotone, and isomer?

  • Isotopes: atoms have the same atomic # but different atomic mass

  • Isobar: same atomic mass but different atomic #’s (a bar has a different number of people)

  • Isotone: different atomic mass and different atomic number (a “tone” has two different sounds)

  • Isomer: same atomic number and the same atomic mass (merge together to get the same thing)

• What is the definition of ionic and covalent bonds?

  • covalent: sharing electrons

  • ionic: transfer of an electron from one atom to another

• What is a molecule and what is a compound?

  • molecule: atoms of various combine to form structures that are called…

  • compound: any quantity of one type of molecule to form…

• What kind of nucleus does an alpha particle have?

  • helium atom

• What is beta emission and alpha emission?

  • Beta emission: energy is created in the nucleus and is then ejected with considerable kinetic energy and escapes the atom … results in the small loss of mass and one unit of negative electric charge from the nucleus .. increasing the atomic # by 1 .. changing one element to another

  • Alpha Emission: emits an alpha particle that consists of 2 P+ and 2 N bound together with an atomic mass of 4 .. chemically different after the change .. nucleus is down 4 amu

• What is Radioactive Half-life?

  • the time required for a quantity of radioactivity to be reduced to one-half its original value .. never quite reaches zero .. varies from less than one second to many years

• What are the types of ionizing radiation?

  • particulate radiation

  • electromagnetic radiation

  • the differences between types are: mass, energy, velocity, charge, origin

Chapter 4

• What is a photon?

  • a tiny particle of electromagnetic radiation .. considered the smallest unit of light energy, with no mass and no charge that travels at the speed of light (3.0×10^8)

• What is a sine wave?

  • variations of amplitude over time

• What is a wavelength?

  • the distance from one crest to another

• What is frequency?

  • rate of rise and fall of a wave over a given unit of time

• What is the wave equation?

  • used for both sound and electromagnetic energy .. V=Fxλ

• What is the electromagnetic wave equation?

  • frequency and wavelength are inversely proportional .. c=fλ .. f=c/λ .. λ=c/f

• what are the three most important regions of the electromagnetic spectrum to radiologic science?

  • visible light, x-rays and gamma rays, radiofrequency

• What is the electromagnetic spectrum?

  • with all the various types of energy on the spectrum the photons are essentially the same other than wavelength and frequency .. diagnostic ultrasound is NOT a part of the spectrum ..

• What is visible light?

  • described as wavelengths that travel in a straight line .. the smallest segments on the spectrum yet the only portion we can sense directly

• What is radiofrequency?

  • described in terms of frequency .. covers a big portion on the spectrum .. low energy and long wavelengths .. RF and microwave emissions overlap considerably

• What is ionizing radiation?

  • characterized by the energy contained in the photon .. the frequency of x-radiation is much higher and the wavelength is much shorter .. only difference between gamma rays and x-rays is their origin

• How do x-ray photons and visible light photons behave?

  • visible light behave more like waves

  • x-rays behave more like particles

  • both exhibit both types of behavior → wave particle duality

• What are the 3 degrees of interaction between light and absorbing material?

  • transparency: a window .. allows light to be trasnkitted without being unaltered

  • translucency: foggy glass .. light is still transmitted through but scattered and reduced in intensity

  • Opacity: glass painted black .. no light can pass through

• What is radiopaque vs radiolucent?

  • radiopaque: structures that absorb x-rays (bone)

  • radiolucent: structures that transmit x-rays (lung tissue)

• What is the inverse square law?

  • intensity of electromagnetic radiation is inversely related to the square of the distance from the source

  • I1/I2 = (d2/d1)²

• What is Quantum Theory?

  • also known as quantum mechanics .. a branch of physics that explains the behavior of matter and energy at the atomic and subatomic level

• What is Planck’s Quantum Theory?

  • x-rays are created with speed of light and they exist with velocity or they do not exist at all

  • E=hf (E=energy .. h=Planck’s constant .. f=photon frequency)

• What is the law of conservation of matter?

  • matter can neither be created nor destroyed

• What is the law of conservation of energy?

  • energy can neither be created nor destroyed