RADIATION CHARACTERISTICS - Vocabulary Flashcards (Lesson 5.1)

Vocabulary flashcards covering key terms and definitions from Lesson 5.1: Radiation Characteristics, including kVp, mA, exposure time, inverse square law, HVL, density, contrast, and related concepts.

Kilovoltage peak (kVp)

Maximum or peak voltage of the x-ray tube; controls the energy/penetrating power (beam quality) of the beam.

Voltage

Potential difference between two electrical charges; higher voltage increases electron speed and energy when they strike the target.

X-ray beam quality

Penetrating power or mean energy of the beam; controlled by kilovoltage peak (kVp).

Wavelength

Energy/penetrating ability of radiation; shorter wavelengths have more penetrating power.

X-ray beam quantity

Number of x-ray photons produced; primarily controlled by milliamperage (mA).

Milliampere (mA)

1/1000 of an ampere; controls the number of electrons in the tube and thus the amount of x-rays produced.

Amperage (A)

Unit of electric current; describes the number of electrons flowing through the cathode filament.

Milliampere-seconds (mAs)

Product of milliamperes and exposure time; determines image density; increasing mA requires decreasing exposure time to maintain density.

Exposure time

The interval during which x-rays are produced; measured in impulses (1/60 second); longer exposure increases the number of x-rays.

Density

Overall darkness or blackness of an image; increases with higher kVp or higher mA; higher density means a darker image.

Contrast

Difference between dark and light areas on an image; low kVp yields high contrast; high kVp yields low contrast.

Distance

The distance the beam travels affects intensity; distances include target-surface, target-object, and target-receptor; intensity decreases with distance.

Inverse square law

Beam intensity is inversely proportional to the square of the distance from the source; doubling distance reduces intensity to one quarter.

Half-value layer (HVL)

Thickness of material (usually aluminum) that reduces beam intensity by half; removes low-energy photons and increases penetrating capability.

Penetrating power

Ability of the x-ray beam to pass through matter; higher energy or shorter wavelength increases penetrating power.

Source-to-receptor distance (SRD)

Distance from x-ray source to the receptor; affects beam intensity via the inverse square relationship.

Inverse relationship between mA and exposure time

As mA increases, exposure time should decrease to maintain constant image density (and vice versa).

Exposure factors

Three settings used to control the beam: kilovoltage (kV), milliamperage (mA), and exposure time.