Concepts of Radiologic Science

1
ConceptsofRadiologicScience
2
Nature of our Surroundings

• All things that are visible can be classified as
  matter or energy
• Matter
• Anything that occupies space and has form or
  shape
• Energy
• The ability to do work

3
Matter

• A primary, distinguishing characteristic of
  matter is mass (measured in kilograms)
• Mass
• The quantity of matter contained in any physical
  object.
• Weight is used to describe the mass of an object
  in a gravitational field.

4
Energy

• Types of Energy (measured in joule)
• Potential energy
• The ability to do work by virtue of position
• Kinetic energy
• Energy of motion
• Chemical energy
• Energy released by a chemical reaction
• Electrical energy
• Represents the work that can be done when an
  electron or an electronic charge moves through an
  electric potential

5
Energy

• Thermal Energy
• The energy of motion at the molecular level
• Nuclear Energy
• The energy contained in the nucleus of an atom
• Electromagnetic Energy
• Ever present, all around us is a state of energy,
  electromagnetic energy. It is the type of energy
  in x-rays

6
Law of Conservation of Energy

• Energy may be transformed from one form to
  another but cannot be created or destroyed. The
  total amount of energy is constant.

7
Albert Einsteins theory of relativity

• Matter and energy
• Are interchangeable
• described by the
• mass-energy
• equivalence equation

8
RadiationThe transfer of energy through space

• Exposed or irradiated
• Matter that intercepts
• radiation and absorbs
• part or all of it

9
Ionizing radiationThe removal of an electron
from an atom
Ionization occurs when an x-ray passes close
enough to an orbital electron of an atom to
transfer sufficient energy to the electron to
cause it to escape from its atom.
10
Sources of Ionizing Radiation

• Natural occurring environmental radiation
• Man made radiation

11
Sources of Natural Occurring Ionizing Radiation

• Cosmic rays
• Particulate and electromagnetic radiation emitted
  by the sun and stars
• Terrestrial radiation
• Emitted from deposits of uranium, thorium, and
  other radionuclide in the earth
• Internally deposited radionuclide
• Natural metabolites such as potassium-40 that are
  internally deposited and have been part of the
  environmental radiation for as long as humans
  have been on Earth

12
Man made Ionizing Radiation

• Diagnostic x-rays
• The largest source of man-made ionizing radiation
• Nuclear power generation
• Research applications
• Industrial sources
• Consumer items
• Watch dials, exit signs, smoke detectors, camping
  lantern mantles and airport surveillance systems

13
History of Radiography

• November 8, 1895
• Roentgen discovered x-rays by accident
• Working with crooks tube and barium
  platinocyanide plate

14
Amazing features of discovery of x-rays

• Discovery was accidental
• There were other people that were working with
  the same substances as Roentgen
• Within a month Roentgen had discovered nearly all
  the properties of x-rays that we know today

15
History of Radiography

• 1896 Pupin introduced the intensifying screen
• 1904 Loenard introduced the double emulsion film
  but wasnt marketed until 1918
• During World War I glass plates were replaced by
  cellulose nitrate for film

16
History of Radiography

• 1898 Thomas A. Edison introduced the fluoroscope
• Edison stopped his research with x-rays after the
  death of his assistant Clarence Daily due to
  x-ray induced injuries
• Early 1900s Rollins, a dentist, introduced
  collimation and filtration
• 1907 Snook transformer was introduced

17
History of Radiography

• 1913 Coolidge tube was introduced and put
  together with the Snook transformer to give the a
  version of the modern x-ray tube
• 1921 potter-Bucky grid was introduced
• 1946 Bell amplifier tube

18
History of Radiography

• 1960 Sonography
• 1970 PET and CT
• 1980 MRI, Digital and PACS
• Today Fusion technology and Magnetoencepholography
  (MEG)

19
Reports of Radiation Injury

• Injuries related to radiation of x-rays were
  common among the early pioneers.
• 1910 with the introduction of shorter exposure
  times, lead aprons, shields and radiation
  monitioring.

20
Today

• ALARA As low as reasonably achievable
• NCRP guidelines
• ICRP giudelines

21
Minimizing radiation exposure today

• Filtration
• Collimation
• Intensifying screens
• Protective apparel
• Gonadal shielding
• Protective barriers

22
The End