Radiographic Imaging Sciences Practice Flashcards

Comprehensive vocabulary flashcards covering the discovery of X-rays, basic physics, atomic structure, radiation characteristics, and X-ray circuit components.

Wilhelm Conrad Röntgen

The scientist who discovered X-rays on November 8, 1895, while experimenting with a Crookes cathode ray tube.

Barium platinocyanide

The fluorescent material coating the paper plate that first reacted during the discovery of X-rays.

Natural radioactivity

The spontaneous emission of particles or energy from the unstable nucleus of an atom.

Thomas Edison

Developer of the first commercially practical fluoroscope using calcium tungstate.

William Coolidge

Inventor of the hot-cathode vacuum tube, which improved X-ray output predictability.

Potter-Bucky diaphragm

A moving grid invented by Gustav Bucky and Hollis Potter to reduce scatter radiation.

Clarence Dally

Thomas Edison’s assistant and the first American X-ray fatality, dying in 1904 from radiation damage.

Crookes tube

A partially evacuated (cold-cathode) tube that produced electrons erratically using residual gases.

Coolidge tube

A fully evacuated vacuum tube that uses a heated tungsten filament to allow independent control of intensity and penetration.

Grid Function

Placed between the patient and image receptor to absorb scattered radiation and increase image contrast.

Radiopaque

The characteristic of materials like lead strips in a grid that do not allow X-rays to pass through easily.

Radiolucent

The characteristic of materials like aluminum or plastic fiber in a grid that allow X-rays to pass through easily.

Computed Radiography (CR)

A technology utilizing a cassette with a photostimulable phosphor plate that requires processing in a separate laser reader.

Direct Digital Radiography (DR)

A technology utilizing a built-in flat-panel detector that converts X-rays directly into electronic signals for instant display.

ALARA

The basic principle of radiation protection standing for "As Low As Reasonably Achievable."

3 Cardinal Rules of Protection

Time (minimize), Distance (maximize), and Shielding (use lead aprons/barriers).

Fluorescence

The immediate emission of visible light during exposure to radiation.

Phosphorescence

The delayed emission of visible light after the radiation source has ceased, also known as "afterglow."

Thermionic Emission

The process of "boiling off" electrons from a heated tungsten filament.

Image Intensifier

An electronic device used in fluoroscopy to clean up and brighten the real-time dynamic image.

Bohr Model

An atomic model where electrons orbit a central, dense nucleus of protons and neutrons in discrete energy shells.

Atomic Number (Z)

The number of protons in the nucleus which defines the identity of the element.

Atomic Mass (A)

The total number of nucleons (protons + neutrons) inside the nucleus.

Electron Binding Energy

The energy required to remove an electron from its shell, measured in electron volts ($eV$).

Ionization

The process where an incoming photon or particle transfers enough energy to eject an orbital electron, creating an ion pair.

Maximum Electrons per Shell Formula

The mathematical formula defined as $2n^2$, where $n$ is the principal quantum number.

Octet Rule

The rule stating that the outermost electron shell of any atom can never hold more than 8 electrons.

Isotopes

Atoms sharing the same atomic number ($Z$) but having different atomic mass numbers ($A$) due to different neutron counts.

Half-life

The time required for a radioisotope to decay to exactly half of its original radioactive activity level.

Effective Dose

A radiation metric accounting for the type of radiation and the radiosensitivity of the exposed organs.

X-rays vs. Gamma Rays

Indistinguishable in properties; X-rays are man-made in electron shells, while Gamma rays originate from the nucleus.

Speed of Light ($c$)

The constant velocity at which all electromagnetic radiation travels, equal to $3 \times 10^8\,\text{m/s}$.

Wave Equation

The relationship expressed as $c = \nu \times \lambda$ (Velocity = Frequency $\times$ Wavelength).

Inverse Square Law

The principle that radiation intensity is inversely proportional to the square of the distance from the source: $I_1 / I_2 = (D_2 / D_1)^2$.

Photons

Massless packets of pure energy that make up electromagnetic radiation such as X-rays and gamma rays.

Alpha Particles

Particulate radiation consisting of 2 protons and 2 neutrons with a heavy mass, high ionizing power, and a $+2$ charge.

Beta Particles

Fast-moving electrons emitted from a decaying nucleus with a light weight and a $-1$ charge.

Superconductors

Materials like titanium that exhibit zero resistance to electron flow at ultra-low temperatures.

Ohm's Law

The electrical relationship defined as $V = I \times R$, where Voltage equals Current multiplied by Resistance.

Alternating Current (AC)

Electric current that continually reverses its direction of flow in a sinusoidal waveform.

Mutual Induction

Process where a changing current in a primary coil induces current in a completely separate secondary coil.

Self-Induction

Process where a single coil induces an opposing electromotive force within itself when its magnetic flux lines change.

Induction Motor

A device using an external stator to spin an internal copper rotor to turn the anode target without physical contact.

Step-up Transformer

A device in the secondary circuit that increases voltage while proportionally decreasing current.

Step-down Transformer

A device in the filament circuit that lowers voltage while raising amperage to facilitate thermionic emission.

Rectifiers

Solid-state silicon semiconductors that convert AC into DC to ensure electrons move only from cathode to anode.

Voltage Ripple

The variation in peak voltage; Single-phase is $100\%$, Three-phase is $4\% \text{--} 13\%$, and High-frequency is less than $1\%$".

Autotransformer

A component operating on self-induction that serves as the primary $kVp$ selector by choosing the input voltage.

AEC (Automatic Exposure Control)

A system that measures exit radiation and terminates the exposure once the detector reaches a full pre-set level.

Rheostat

A variable resistor in the filament circuit that serves as the $mA$ selector.