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Milliamperes (mA)

The current flow through the cathode filament during exposure, a quantitative factor that changes photon quantity in radiography.

Effect of increasing mA

Produces a greater number of electrons for x-ray production, thereby increasing the number of x-ray photons.

mA and film blackening relationship

Film blackening is proportional to mA; doubling mA doubles the blackening, while halving mA reduces it by half.

Focal Spot Blooming

The increase in actual focal spot size due to increased tube current (mA), which can adversely affect radiograph quality.

Exposure time in radiography

Sets the length of time for an exposure, combined with mA to determine exposure rate.

Reciprocity Law

States that blackening on the film remains constant as long as the total energy exposing the film is constant.

Inverse Square Law

Describes how the intensity of radiation decreases with increasing distance from the source, reducing intensity to a quarter when the distance is doubled.

Characteristics of a high-quality radiograph

Contains maximum information for review, sharp image, appropriate blackening, excellent subject contrast, and minimal distortion.

Quality Evaluation Factors in radiography

Includes density, contrast, definition, and distortion; controlled by technique selection and use of radiographic accessories.

Density in radiography

Blackening on the finished radiograph produced by the development of exposed silver halide crystals in the film emulsion.

Contrast in radiography

Variation in density levels across the film that makes anatomic detail visible.

Definition in radiographic quality

Refers to the clarity and distinctness of the fine structural lines or borders of anatomic parts recorded in a radiograph.

Distortion in radiography

Misrepresentation or undesired change of the size and/or shape of the anatomic part of interest.