Dental Radiology

Radiograph with many light and dark areas, but FEW shades of grey is said to have....

High contrast

few shades of gray with high contrast is prooduced with------kVp

low kvp

increasing mA alone results in a film with

increased density

film produced using 90 kVp and 0.25 seconds. what exposure time is needed to produce the same at 75 kVp ?

0.50 seconds

The total energy contained in the xray beam in a specific area at a given time is termed....


Increasing these will increase the intensity of the x-ray beam?

kVp, mA, and exposure time

The HVL is the amount of..

Aluminum needed to reduce the x-ray beam intensity by half.

The kVp range for most dental x-rays is

65-100 kV

A higher kVp produces x-rays with

more penetrating ability

Radiation produced with high kVp results in

short wavelengths

increasing mA results in an increase in

Temp of filament and number of x-rays produced

the mA range for dental radiography is

7 to 15 mA

Thermionic emission occurs in the

negative cathode

which radiation accounts for 70% of all the x-ray energy produced at the anode?

General radiation

Which radiation occurs only at 70 kVp or higher ad accounts for a very small part of dental x-rays produced?

Characteristic radiation

Primary radiation best described as

radiation exists the tubehead

Which type of scatter happens most often with dental x-rays?


why is an increased target film distance required in the paralleling technique?

to avoid image magnification

Thin transparent coating that is placed over the emulsion.

protective layer

flexible piece of plastic that withstands heat, moisture and chemical heat

film base

Chemical compounds that change when exposed to radiation or light are termed

halides crystals

invisible pattern of stored energy on the exposed film is termed?

latent image

Purpose of a lead foil sheet in the film packet is:

to protect film from back scattered radiation

The -----the crystals, the -------- the film speed

The larger the crystals , the faster the film speed

What regulates the flow of electrical current to the filament of the x-ray tube?

low -voltage circuit

What is used to increase the voltage in the high -voltage circuit?

step-up transformer

Process by which unstable atoms undergo a spontaneous disintegration in an effort to attain a more balance nuclear state?(undergo decay trying
to become more balanced )


Who introduced paralleling tech. and exposed first dental radiograph in the US using a live person?

C. Edmund Kells 1896

Introduced bisecting technique?

Weston Price 1904

Introduced Bite-Wing tech?

Howard Raper 1925

Four components of a film packaging?

x-ray film
paper film wrapper
Lead foil sheet
Outer packaging

The higher the speed of the film....

the faster the film exposure and the less radiation to patient

Four basic Components of x-ray film??

Film base
Adhesive layer
Film Emulsion
Protective layer


Softens emulsion, reduces exposed crystals to black metallic silver


Hardens emulsions, cleans away unexposed crystals ( silver halide)

Chemical components that change when exposed to radiation or light are termed?

silver halide crystals- reduced to black metallic silver

Five Rules for Paralleling tech

Film Placement- most cover teeth to be examined
Film Position- parallel to the long axis
Vertical Angulation- CR directed perpend to film
Horizontal Angulation - CR directed thru contact-open
Film Exposure- center x-ray beam to espose film


2 or more atoms joined by chemical bonds


losing or gaining an electron


Emission or propagation of energy though space or matter, waves or particles

Ionizing Radiation

Radiation that is capable of producing ions by removing or adding electrons to an atom.


Wave speed= speed of light


distance b/t crests- energy and penetrating power


# of wavelenths that pass a given point in a certain amount of time.
Low freq./ Long wavelength = decreased energy
High freq/ short wavelength= increase energy

X- radiation

type of High energy, ionizing electromagnetic radiation

Amperage (mA)

# of electrons moving through the cathode filament

Voltage ( kV)

meaurment of electrical force that causes electrons to move from (-) to (+) pole


Controls the current passing from the cathode to the anode

Speed of light

186,000 miles/sec

Produced when radiation strikes matter, reduces penetrating power

Secondary Radiation

When radiation is deflected off matter

Scatter Radiation

Compton Scatter

x-ray photon is deflected form path during passage through matter

Coherent Scatter

x-ray photon that has its path altered by matter
No change in atom occurs, NO ionization