Dental Radiography: X-Ray Beam Characteristics (Chapter 5)

Vocabulary flashcards summarizing essential terms and relationships related to x-ray beam properties and image quality in dental radiography.

Half-value layer

The thickness of a material required to reduce an x-ray beam’s intensity to one-half of its original value.

Kilovoltage peak (kVp)

The tube voltage that determines the energy (penetrating ability) and QUALITY of the x-ray beam.

Milliamperage (mA)

The tube current that, along with exposure time, determines the QUANTITY of x-rays produced.

Quality of an x-ray beam

A measure of beam energy or penetrating power, controlled primarily by kVp.

Quantity of an x-ray beam

The number of x-ray photons in the beam, governed by mA and exposure time.

kVp range in current dental x-ray units

Typically 60–70 kVp.

mA range in current dental x-ray units

Typically 6–8 mA.

Contrast (radiographic)

The difference in degrees of densities (shades of gray) on an x-ray image.

Density (radiographic)

The overall darkness or blackness of an x-ray image.

Effect of increasing kVp

Raises photon energy, increases image density, and lowers image contrast.

Effect of increasing mA

Increases the number of x-ray photons produced and thus raises overall image density.