c. The Extension Arm. The tube head is attached to the metal extension arm
by means of a yoke that can revolve 360 degrees horizontally where it is connected.
The construction of the yoke also provides vertical movement as well.
d. The Tube Head. Inside the metal tube housing is the x-ray tube. The
diagram in figure 1-2 represents a dental x-ray tube head and a dental x-ray tube. This
tube emits radiation in the form of photons (photons will be discussed in Lesson 2) or
x-rays. X-ray photons expose the film. In addition to exposing the film, it also exposes
the patient to radiation. Unless certain protective measures are taken, the x-ray
technician may also be exposed.
Figure 1-1. A representation of a control panel, x-ray tube head, and extension arm.
Figure 1-2. Dental x-ray tube head and dental x-ray tube.