Radiographic Physics and Digital Imaging Vocabulary

Vocabulary flashcards generated from lecture fill-in-the-blank review sheets on x-ray production, primary/remnant beams, exposure factors, interactions, image quality, distortion, and digital receptor concepts.

Digital Detector (DD)

The digital component hit by x-ray photons to create an image.

Rotor

The rotating component labeled inside the x-ray tube.

Stator

The stationary component surrounding the rotor in the x-ray tube.

Anode

The positive side of the x-ray tube, connected to an anode stem and a tungsten/rhenium anode disk.

Cathode

The negative side of the x-ray tube.

Glass Envelope

The glass structure enclosing the x-ray tube.

Filament

The electron source situated in the focusing cup of the x-ray tube.

Target

The location on the anode where accelerated electrons are stopped to create x-ray photons.

Primary Beam

The photon beam located between the x-ray tube and the patient, also referred to as primary radiation entering the patient.

Remnant Beam

The beam leaving the patient toward the detector (remnant radiation) that creates the final image.

Photoelectric Interaction

The interaction mechanism involving the absorption of photons in matter.

Compton Scatter

The interaction in which photons change direction and lose energy.

Transmission

The process where photons pass through matter completely unaffected.

Attenuation

The reduction in x-ray beam quantity and quality as it passes through matter.

Absorbed Radiation

Radiation that is taken up inside the patient.

Scatter Radiation

Radiation traveling away in another direction that reduces contrast resolution.

Radiographer

The professional in control of the prime exposure factors.

mAs

Abbreviation for milliampere-seconds; measures the amount of electrical current in the tube and controls the amount of radiation produced.

kVp

Abbreviation for kilovoltage peak; measures electrical potential pushing current through the tube and controls beam penetrating ability.

SID

Abbreviation for source-to-image distance; the distance between the x-ray tube and the DD.

Inverse Square Law

The physical law describing how distance affects radiation reaching the IR, where intensity ($I$) is inversely related to distance ($D$) squared.

Grid

A device containing lead placed between the patient and DD that reduces scatter radiation and increases contrast, but increases patient dose due to requiring increased mAs.

Exposure Indicator

A value that numerically represents radiation reaching the DD.

Optimal Signal Value

The signal level demonstrated by the exposure indicator's target number.

Quantum Noise (Mottle)

Image noise resulting from insufficient exposure to the DD.

Inherent Filtration

The natural filtering components of the tube housing grouped together, such as insulating oil and the tube envelope.

Added Filter

Filtration made of aluminum or copper placed between the tube and patient to remove low-energy x-rays and reduce patient dose.

Collimator

The most efficient beam-limiting device.

Exit Port

The opening through which the x-ray beam exits the tube housing.

Brightness

The amount of luminescence of a display monitor, which depends on x-rays received by the DD (signal value).

Contrast Resolution

The ability of an imaging system to distinguish subtle signal-value differences between black and white.

Spatial Resolution

A measure describing the sharpness of object edges.

Penumbra

Fuzzy borders on an image resulting from low spatial resolution.

Umbra

Sharp borders on an image resulting from high spatial resolution.

Magnification

Misrepresentation of object size (size distortion).

Foreshortening

A form of shape distortion alongside elongation.