Chapter 12 Key Terms

Question 1

15 percent rule

Answer 1

an increase in kVp by 15 percent that causes a doubling in exposure, and vice versa

Question 2

Direct square law

Answer 2

a direct relationship is necessary to compensate for the changes in intensity and film density

Question 3

Exposure maintenance formula

Answer 3

a direct square law; mAs must increase when distance increases, and vice versa, in order to maintain image receptor exposure

Question 4

Milliamperage (mA)

Answer 4

a measurement of x-ray tube current—the number of electrons crossing the tube from cathode to anode per second

Question 5

Milliamperage-second (mAs)

Answer 5

the product of tube current and exposure time

Question 6

Penetrability

Answer 6

the ability of the x-ray to pass through structures and tissues

Question 7

Prime factors

Answer 7

factors related to x-ray emission that are under the direct control of the radiographer; milliamperage, kilovoltage, and distance

Question 8

x-ray quality

Answer 8

a measurement of the penetrating ability of the x-ray beam

Question 9

x-ray quantity

Answer 9

a measure of the number of x-ray photons in the useful beam