d. X-ray Photon. Electromagnetic rays produced by the x-ray machine. (The
x-ray photon will be dealt with in greater detail in Lesson 4 of this text.)
SOURCES OF RADIATION
a. General. There are two sources of radiation--natural background radiation
and man-made radiation. Both are harmful to man.
b. Natural Background Radiation. There are three sources of natural
background radiation--cosmic, terrestrial radiations from earth and its environment, and
background radiations from naturally occurring radionuclides. Although natural
background radiation may be harmful, man has lived in this environment without
significant injurious effects since his appearance on earth.
c. Man-Made Radiation. Man-made radiation has many sources. Industry,
medical radiation, and dental radiation account for the majority of man made radiation.
Man-made radiation, used improperly, can be significantly more harmful to man than
TYPES OF RADIATION
a. Particulate. Particulate or corpuscular radiation comes from radioactive
decay or disintegration of radioactive materials. Alpha and beta particles are examples
of this type radiation.
b. Electromagnetic. Electromagnetic radiation covers a very wide spectrum
ranging from electrical power to visible light to x-rays and gamma rays. The portion of
the electromagnetic spectrum most important to us in this particular study is the x-ray
Section II. PRODUCTION OF X-RAYS
PARTS AND COMPONENTS OF THE DENTAL X-RAY MACHINE
a. General. The standard structural parts of the dental x-ray machine include a
control panel (usually mounted behind a protective shield), a tube head that houses the
dental x-ray tube, and a flexible extension arm from which the tube head is suspended
(see figure 1-1).
b. The Control Panel. The components of the control panel are switches, dials,
gauges, and lights. Basically, each control panel has the same function. The
arrangement and location of these components will differ, depending upon the make,
model, and year of construction of the dental x-ray unit. An operator's manual is issued
with each unit. The operator should study it until he is familiar with its operational