Introduction to the Imaging Sciences - Radiation and its Discovery

Vocabulary flashcards covering the discovery of x-rays, radiation safety history, types of energy, radiologic SI units, and properties of x-rays.

Wilhelm Conrad Roentgen

The German scientist who discovered x-rays using a Crookes's tube vacuum tube.

Crookes's Tube

A vacuum tube covered with black cardboard that Wilhelm Conrad Roentgen used during the discovery of x-rays.

Barium Platinocyanide

The fluorescent chemical coating on cardboard that glowed when placed near an energized Crookes's tube, leading to the discovery of x-rays.

First Radiograph

The world's first radiograph, produced on December 22, 1895, showing Bertha Ludwig's hand after a $15$\,minute exposure.

Acute Radiodermatitis

A skin injury resulting from radiation overexposure suffered by many early patients and equipment operators due to long exposure times.

Clarence Dally

Assistant to Thomas Edison who suffered severe radiation burns that resulted in the amputation of his arms and his death in $1904$.

Energy

The ability to do work, which can exist in chemical, thermal, electrical, or electromagnetic forms.

Potential Energy

Stored energy.

Kinetic Energy

Energy in motion, or energy being expended.

Electromagnetic Energy

A form of energy that behaves like both waves and particles.

Exposure

The measure of radiation exposure intensity from the tube, defined as the amount of ionization or electrical charge in a specified amount of air; measured in Coulomb per kilogram ($\text{C/kg}$).

Absorbed Dose

The transfer of radiation energy into matter, such as patient tissue; measured in Gray ($\text{Gy}$).

Dose Equivalent

The unit of measurement used to track occupational radiation exposure; measured in Sieverts ($\text{Sv}$).

Radioactivity

The process of radioactive disintegration or decay in which unstable atoms emit energy from the nucleus to reach stability; measured in Becquerels ($\text{Bq}$).

Speed of X-rays

The velocity of x-rays in a vacuum, equal to the speed of light: $3 \times 10^8$\,m/s ($186,000$\,miles per second).

Polyenergetic Beam

An x-ray beam composed of photons possessing many different energy levels, with the maximum energy established by the radiographer.

Diagnostic Medical Range

The standard energy range of x-rays used in medical imaging, extending from $30$\,kV to $150$\,kV.

Secondary Radiation

Radiation created when an x-ray photon is absorbed by matter and causes a secondary photon to be emitted.