Chapter 3 Radiation

In dental imaging, the quality of the x-ray beam is controlled by

• kilovoltage

• milliamperage

• exposure time

• source to receptor distance

Tags

NGSS.HS-PS4-5

Identify the kilovoltage range for current dental x-ray machines.

• 50-60 kV

• 60-70 kV

• 70-100 kV

• greater than 100 kV

Answer explanation

The average range for most dental x-ray machines is 65-100kV. Lower settings may not penetrate the tissue adequately and cause high contrast images; higher settings increase the radiation the patient receives and cause low contrast images.

A higher kilovoltage produces x-rays with:

• greater energy levels

• shorter wavelengths

• more penetrating ability

• all of the above

Answer explanation

An increase in kilovoltage increases the quality of the beam. It will demonstrate greater energy and shorter, more penetrating wavelengths.

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-4

Identify the unit of measurement used to describe the amount of electric current flowing through the x-ray tube

• volt

• ampere

• kilovoltage

• force

Radiation produced with high voltage results in:

• short wavelengths

• long wavelengths

• less penetrating radiation

• lower energy levels

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3

In dental imaging, the quantity of radiation produced is controlled by:

• kilovoltage

• milliamperage

• exposure time

• milliamperage and exposure time

Increasing milliamperage results in an increase in:

• temperature of the filament

• mean energy of the beam

• number of x-rays produced

• both a and c

Tags

NGSS.HS-PS4-3

Identify the milliamperage range used for current dental x-ray machines

• 1 - 5 mA

• 6 - 8 mA

• 9 - 15 mA

• greater than 15 mA

Answer explanation

The recommended mA setting for dental imaging is 6-8 mA. A setting above 15 mA may cause excessive heat in the x-ray tube.

The overall blackness or darkness of an image is termed

• contrast

• density

• overexposure

• polychomatic

If kilovoltage is decreased with no other variations in exposure factors, the resultant image will:

• appear lighter

• appear darker

• remain the same

• either a or b