Radiography Notes: Prime Factors and X-ray Emission (Vocabulary)

Vocabulary flashcards covering key terms and concepts from the lecture notes on prime factors and x-ray emission.

Prime Factors

The three main factors affecting x-ray emission: mAs, kVp, and distance (SID).

mAs

The product of milliamperage (mA) and exposure time (seconds); determines the quantity of x‑rays reaching the receptor and affects image density.

mA

The tube current; rate of electron flow from cathode to anode; directly proportional to radiation quantity and image density, inversely related to exposure time to maintain density.

Exposure Time

The duration of the x-ray exposure in seconds; used with mA to form mAs.

kVp

Kilovoltage; controls beam energy (quality) and, to some extent, beam quantity; higher kVp increases penetration.

SID

Source-to-Image Distance; distance from the x-ray tube to the image receptor; affects exposure required (farther SID requires more mAs; closer SID requires less).

Primary Factors

The three main factors affecting x-ray emission: mAs, kVp, and distance (SID).

Distance

Another term for SID; the space between the x-ray source and the image receptor that influences exposure.}

Exposure Index

A readout indicating the level of x-ray exposure on a image; underexposure is indicated by a low index, prompting adjustments in mA.

Exposure

The amount of radiation delivered to the image receptor; influences image receptor density.

Density

Radiographic density; overall brightness of the image; directly proportional to exposure.

Visibility

The ability to see details on a radiograph; depends on exposure and image contrast.

Receptor Contrast

The difference in grayscale on the image due to attenuation differences in tissues; part of image quality in the photographic domain.

Sharpness

Clarity of edges and fine detail; related to geometric properties and focal spot size.

Spatial Distortion

Geometric misrepresentation of the size or shape of the object on the image caused by geometry and alignment.

Resolution

Ability to distinguish small details; higher resolution means more image detail.

Anode

Positive electrode in the x-ray tube; tungsten/rhenium disk that serves as the target for electrons to produce x-rays.

Cathode

Negative electrode in the x-ray tube; contains the filament and focusing cup; source of electrons.

Filament

Thin tungsten wire heated to emit electrons (thermionic emission) for x-ray production.

Focusing Cup

A metal cup at the cathode that directs the electron beam toward the anode for better image quality.

Rotor

Component that rotates the anode to distribute heat and prevent overheating.

Stator

External electromagnetic coils that drive the rotor to spin the anode.