The Dental X-ray Machine

Reference Reading Chapter 2: pp. 15 - 17

X-rays are produced within the dental x-ray machine

The x-ray machine can be divided into 3 study areas◦ Component Parts◦ The x-ray tube◦ X-ray generating apparatus

X-ray Machine

The Dental x-ray machine consists of 3 visible component parts:◦ The Control Panel

◦ The Extension Arm

◦ The Tubehead

Component Parts

The Component Parts of the Dental X-ray Machine

The Control Panel contains:◦ On-off switch and an indicator light◦ The exposure button and an indicator light◦ Control devices to regulate the x-ray beam

Time setting kVp setting mA setting

The Control Panel

Control Panels

Older style Newer Design

The extension arm suspends the x-ray tubehead and houses the electrical wires that extend from the control panel to the tubehead

The extension arm allows for movement and positioning of the tubehead

The Extension Arm

Tubehead The tubehead is a

tightly sealed, heavy metal housing that contains the x-ray tube. The x-ray tube produces the dental x-rays

The component parts of the tubehead include:◦ Metal housing◦ Insulating oil◦ Tubehead seal◦ X-ray tube◦ Transformer◦ Aluminum disk/filter◦ Lead collimator◦ Position Indicating Device (P.I.D.)

Tubehead

Component Parts of the Tubehead

Metal Housing

The Metal Housing, or body, of the tubehead surrounds the x-ray tube and is filled with oil.

It protects the x-ray tube and grounds the high voltage components.

Component Parts of the Tubehead Insulating Oil – the oil

that surrounds the x-ray tube.

It prevents overheating by absorbing the heat created when x-rays are produced

Component Parts of the Tubehead Tubehead Seal – the

aluminum or leaded glass covering of the tubehead that permits the exit of x-rays from the tubehead.

It seals the oil in the tubehead

Component Parts of the Tubehead The X-ray tube – the

heart of the x-ray generating system.

Component Parts of the Tubehead Aluminum Disks –

sheets of 0.5 mm aluminum placed in the path of the x-ray beam.

This filters out the longer wavelength, non-penetrating x-rays.

Text – p. 15, Fig. 2-14

Component Parts of the Tubehead Lead Collimator – a lead

plate with a central hole that fits directly over the opening of the metal housing where the x-rays exit the tubehead.

Restricts the size of the x-ray beam to 2.75 inches at the patient’s face.

Component Parts of the Tubehead

Different tubehead lengths

Position Indicating Device (P.I.D.) – aims and shapes the x-ray beam as it exits the tubehead.

Sometimes called the “cone”

Cathode is the negative electrode of the x-ray tube.

The purpose of the electrodes is to supply the electrons necessary to generate x-rays.

The cathode consists of:◦ Tungsten filament- generates the electrons that

produce the x-rays at the tungsten target◦ Molybdenum cup

Cathode

The anode is the positive electrode within the x-ray tube

The purpose of the anode is to convert the electrons into x-ray photons at the tungsten target.

The anode consists of:◦ The tungsten target◦ The copper stem

Anode