chap 1

Matter ∙ Anything that occupies space & has mass

Atoms ∙ The building blocks of matter

Mass ∙ The quantity of matter as described by its energy equivalence

∙ The distinguishing characteristic of matter

Weight ∙ The force exerted on a body under the influence of gravity

Matter ∙ Material substance with mass of which physical objects are composed

Atoms & Molecules ∙ The fundamental, complex, building blocks of matter

Energy ∙ The ability to do work

∙ SI Unit: joules (J)

∙ In Radiology: electron volt (eV)

Potential Energy ∙ The ability to do work by virtue of position

Kinetic Energy ∙ The energy in motion

Chemical Energy∙ The energy released by a chemical reaction

Electrical Energy ∙ The work that can be done when an electron moves through an electric potential difference (V)

Thermal/Heat Energy ∙ The energy in motion at the molecular level

Nuclear Energy ∙ The energy that is contained within the nucleus of an atom

Electromagnetic Energy ∙ The type of energy that is used in an x-rays

Theory of Relativity ∙ Albert Einstein ∙ States that matter and energy are interchangeable

Matter-Energy Equivalence ∙ Formula: E=mc2

Radiation ∙ The energy emitted & transferred through space

Visible Light ∙ Radiated by the sun

Exposed/Irradiated ∙ Matter that intercepts & absorbs radiation

UV Light ∙ It causes sunburn

Ionizing Radiation ∙ Any type of radiation that is capable of removing an orbital electron from the atom with which it interacts ∙ Examples: x-rays, gamma rays & UV light

Ionization ∙ The removal of an electron from an atom

Particulate-type Ionizing Radiation - ∙ Examples: alpha & beta particles

Natural Environmental Radiation

∙ Annual Dose: 300 mrem/yr

∙ Cosmic Rays: emitted by sun & stars

∙ Terrestrial Radiation: deposits of uranium, thorium & other radionuclides

∙ Internally-deposited Radionuclides: potassium-40 (natural metabolites)

∙ Radon: largest source

Man-made Radiation

∙ Annual Dose: 60 mrem/yr

∙ Diagnostic X-rays: largest source (39 mrem/yr)

NCRP ∙ National Council on Radiation Protection & Measurements

MSCT ∙ Multislice Spiral Computed Tomography

Medical Applications of Ionizing Radiation

∙ Annual Dose: 50 mrem/yr

Cathode Rays ∙ Electrons

Sir William Crookes ∙ He invented crookes tube

Wilhelm Roentgen ∙ He discovered x-rays

November 8, 1895 ∙ Discovery of x-rays ∙ Wurzburg University in Germany

Barium Platinocyanide ∙ The fluorescent material used by Roentgen

Fluorescence ∙ The emission of visible light only during stimulation

1901 ∙ Roentgen received Nobel Prize in Physics

February 1896 ∙ He published and produced the first medical x-ray image ∙ The first x-ray examination

Radiography ∙ Uses x-ray film & x-ray tube mounted from the ceiling ∙ Provides fixed images

Fluoroscopy ∙ Conducted with an x-ray tube located under the examination table ∙ Provide moving images

X-ray Voltage ∙ Measured in kVp

X-ray tube Current ∙ Measured in mA

Image Blur ∙ Caused: long exposure time

Michael Pupin (1896) ∙ He demonstrated the use of radiographic intensifying screen

Charles L. Leonard (1904) ∙ He demonstrated the use of double emulsion film

Thomas A. Edison (1898) ∙ He developed fluoroscope ∙ Original Fluorescent Material: Barium platinocyanide ∙ Most Recent: Zinc cadmium sulfide & calcium tungstate

Clarence Dally (1904) ∙ The first x-ray fatality

William Rollins ∙ He demonstrated the first application of collimation & filtration

H.C. Snook (1907) ∙ He introduced interrupterless transformer ∙ Snook transformer

William D. Coolidge (1913) ∙ He introduced coolidge x-ray tube

Gustav Bucky (1913) ∙ He invented stationary grid ∙ “glitterblende”

Hollis Potter (1915) ∙ He invented moving grid

1921 ∙ Potter-Bucky grid was introduced

1970 ∙ PET & CT were developed

1980 ∙ MRI become an accepted modality

MEG ∙ Magnetoencephalography

Filtration ∙ It absorbs low energy x-rays ∙ Aluminum or copper

Collimation ∙ It restricts the useful x-ray beam ∙ It reduces scatter radiation ∙ It improves image contrast ∙ Example: adjustable light-locating collimators (common)

Intensifying Screen ∙ It reduces x-ray exposure by more than 95%

Protective Apparel ∙ Lead-impregnated material ∙ Examples: gloves & apron

Light Amplifier (1946) ∙ He demonstrated at Bell Telephone Laboratories

1950 ∙ Light amplifier was adapted for fluoroscopy

1960 ∙ Diagnostic UTZ & gamma camera appeared

Gonadal Shielding ∙ It is used with all persons of childbearing age

Protective Barriers ∙ Lead-lined with a leaded-glass window ∙ Example: radiographic control console

ARRT ∙ American Registry of Radiologic Technologists