Production of X Rays - Dental Radiology.

PARTS AND COMPONENTS OF THE DENTAL X-RAY MACHINE:

General:- The standard structural parts of the dental x-ray machine include a control panel (usually mounted behind a protective shield); a tube head, which houses the dental x-ray tube; and a flexible extension arm from which the tube head is suspended (see figure 1-1).

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 capability.

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.

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.


THREE STEP PROCESS OF X-RAY PRODUCTION:

The First Step:- The first step in x-ray production is to turn on the machine. (If there is doubt on the part of the x-ray technician concerning the operation of the unit, reference should be made to the operator's manual.) When the unit is turned on, the filament of the cathode is heated by electrical current, causing it to emit electrons (see figure 1-3).

Introduction to Dental Radiography.

INTRODUCTION:

1. GENERAL:

Radiography is a highly technical field, indispensable to the modern dental practice, but presenting many potential hazards. The dental radiographic specialist must be thoroughly familiar with the procedures necessary to produce radiographs of diagnostic quality. He must also have a thorough knowledge of the hazards associated with the use of radiation and how to protect himself and the patient against those hazards. This lesson deals with the production, characteristics, and effects of radiation and how it may be used safely in dentistry.

2. DISCOVERY OF X-RAYS:

In 1895, Wilhelm Konrad Roentgen was searching for invisible light by experimenting with a Crookes vacuum discharge tube. This is a glass tube in which the vacuum is nearly complete, having a negative electrode (cathode) and a positive electrode (anode). Many investigators believed that invisible light rays were emitted from the negative electrode when a high voltage current was sent through the tube. With the room darkened and the tube covered with black paper, Roentgen passed a high voltage current through the Crookes tube and was surprised to observe that a fluorescent screen lying on a table at some distance was glowing brightly. He then noted that a shadow was produced when an object was placed between the tube and the screen. Further experimentation revealed that the rays that caused the fluorescent screen to glow also acted upon the emulsion on photographic plates in the same manner as light. Thus it was shown that the rays produced would pass through some substances through which light would not pass. Since Roentgen was unable to determine the exact nature of the rays produced, he referred to them as x-rays (x being commonly used to denote an unknown factor). In later years scientists have referred to them as Roentgen rays.